S. Regan Agam; R. Wicaksono; H.A. Nugroho
2026 23rd International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON)
Year: 2026 | Conference Paper | Publisher: IEEE
W.A. Dharma; A.A.A. Rizqi; R. Wicaksono
2026 International Seminar on Intelligent Business and Edge-Computing Research (ISIBER)
Year: 2026 | Conference Paper | Publisher: IEEE
R. Wicaksono; N.A. Setiawan; B. Sun; M. Takei
IEEE Sensors Journal
Year: 2026 | Journal Article | Volume: 26, Issue: 8 | Publisher: Institute of Electrical and Electronics Engineers (IEEE)
T.E. Prabowo; W. Najib; S. Wibirama
2026 International Conference on Current Research in Artificial Intelligence and Data Science (ICCRAIDS)
Year: 2026 | Conference Paper | Publisher: IEEE
T. Krisdiyanto; I. Ardiyanto; S. Wibirama
2026 International Conference on Current Research in Artificial Intelligence and Data Science (ICCRAIDS)
Year: 2026 | Conference Paper | Publisher: IEEE
I. Agustian; I. Ardiyanto; S. Wibirama
Green Technologies and Sustainability
Year: 2026 | Journal Article | Volume: 4, Issue: 2 | Publisher: Elsevier BV
E.Y. Putro; P. Murti; A. Widyaparaga; I.M. Miasa
Atlantis Highlights in Engineering
Year: 2026 | Book Chapter | Publisher: Atlantis Press International BV
X. Yu; Z. Tu; A. Widyaparaga; D. Darlianto; S.H. Chan
Renewable Energy
Year: 2026 | Journal Article | Volume: 256 | Publisher: Elsevier BV
F.T. Dwi Atmaji; Jamasri; H.A. Yuniarto; I.M. Miasa
Array
Year: 2026 | Journal Article | Volume: 30 | Publisher: Elsevier BV
R. Bachmid; A. Widyaparaga; M.A. Bramantya; I.M. Miasa; J.L. Ardi
Year: 2026 | Journal Article | Publisher: Elsevier BV
J.L. Ardi; I.M. Miasa; A. Widyaparaga; M.A. Bramantya; R. Bachmid
Applied Research
Year: 2026 | Journal Article | Volume: 5, Issue: 4 | Publisher: Wiley
Abstract: ABSTRACT
Water scarcity has become a critical global issue due to the continuous increase in clean water demand. Atmospheric water harvesting (AWH) through condensation offers a promising and sustainable alternative. However, its performance is often limited by inefficient droplet shedding. Accumulated droplets increase thermal resistance, block active nucleation sites, and reduce the overall water collection rate. Although surface modifications have been developed to improve nucleation and droplet transport, challenges such as contact line pinning and delayed droplet release remain significant. This study proposes a synergistic enhancement strategy by integrating passive and active approaches through hybrid patterned surfaces combined with mechanical vibration. The hybrid surface forming a leaf‐like pattern was created in two ways first, by polishing with 1000‐grit sandpaper to create a hydrophilic surface. After that, a pattern resembling a leaf‐like pattern was created at a 45‐degree angle using a seal type to cover the hydrophilic surface. Then, the gaps between the patterns were coated using a nano‐ceramic liquid coating to create a hydrophobic area that functions to accelerate the fall of water droplets. Experiments were conducted at a relative humidity of 80% ± 5%. Periodic mechanical vibrations were applied using sinusoidal sweep mode (80–1000 Hz) and monofrequency operation at 240 Hz. The results demonstrate that mechanical vibration accelerates droplet coalescence and shedding, thereby reducing thermal resistance and decreasing the critical droplet size for detachment. Compared to the no‐vibration condition, the water collection rate increased from 151 to 272 g/m
2
h under monofrequency vibration at 240 Hz, corresponding to a 79% enhancement in heat transfer coefficient. These findings confirm that the integration of hybrid surfaces and controlled mechanical vibration effectively improves condensation performance and enhances the efficiency of atmospheric water harvesting systems.
R. Bachmid; A. Widyaparaga; M.A. Bramantya; I.M. Miasa; J.L. Ardi
Results in Engineering
Year: 2026 | Journal Article | Volume: 30 | Publisher: Elsevier BV
F.W. Saputra; B. Arifvianto
Journal of Physics: Conference Series
Year: 2026 | Journal Article | Volume: 3186, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
S45C medium carbon steel is commonly utilized as a hydraulic cylinder rod material due to its excellent toughness and ductility. This research investigates the influence of chromium plating duration on the microstructure, hardness, wear, and corrosion resistance of S45C steel. The electroplating process involved immersing the steel specimens in a solution composed of 250 l of chromic acid and 20 l of sulfuric acid, under a constant current of 84 A/mm
2
, with durations varied from 30 to 150 min. Coating thickness at the surface of the steel specimen was examined as well as its microstructure and hardness. The wear and corrosion rates were determined in this research. The result of this study revealed that the highest hardness, i.e., 10.52 GPa, could be obtained with 60 min of plating, it has been determined that the hardness increased by approximately 7.6 to 8.9 GPa compared to the initial hardness of the S45C steel substrate. The lowest specific wear rate, i.e., 1.520 × 10
−6
mm
3
/kg·m, was obtained using the Ogoshi wear test method. A corrosion rate of 0.03 mm/year was obtained at 30 min of electroplating, while the largest layer thickness, i.e., 130 µm, was achieved after 150 min of electroplating.
B.W.B. Santoso; A. Sugijopranoto; B. Arifvianto; M. Mahardika
AIP Conference Proceedings
Year: 2026 | Conference Paper | Volume: 3358 | Publisher: AIP Publishing
Y.V. Yoanita; I. Perdana; M.A. Muflikhun; B. Arifvianto; M. Mahardika
Materials Letters
Year: 2026 | Journal Article | Volume: 409 | Publisher: Elsevier BV
A. Prasojo; M. Mahardika; R. Dharmastiti; J. Zhou; B. Arifvianto
Journal of Biomimetics, Biomaterials and Biomedical Engineering
Year: 2026 | Journal Article | Volume: 73 | Publisher: Trans Tech Publications, Ltd.
Abstract: The medical grade 316L stainless steel has been widely used for biomedical implants, including bone tissue engineering scaffolds due to its excellent mechanical properties and biocompatibility. The space holder method offers a promising approach to producing highly porous 316L stainless steel scaffolds. However, several challenges in the implementation of this method remain unresolved, particularly the difficulties in controlling the geometrical changes of space holder particles during the compaction of stainless steel/carbamide powder mixtures, leading to inability to control pore characteristics of the scaffolds produced. In this study, the compaction behavior of stainless steel/carbamide powder mixtures was investigated to understand the interactions between metal particles and space holder particles in the preparation of porous stainless steel scaffolds. The impacts of key process parameters on the green density, such as the specific net energy applied during the process and the yield pressure derived from loading-unloading compression cycles, were analyzed with the aid of the Heckel model. The study provides useful insights into these relationships, facilitating the optimization of the compaction process to achieve desired scaffold architecture and contributing to consistent fabrication of porous 316L stainless steel scaffolds.
A.A. Wibawa; B. Arifvianto; R. Dharmastiti; H.D.K. Yulianto; D. Pramono
Jurnal Teknosains
Year: 2026 | Journal Article | Volume: 15, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Denture fabrication plays an important role in restoring oral functions, including mastication, speech, and esthetics, while also helping to prevent temporomandibular joint disorders. Conventional denture bases are commonly fabricated using heat-cured acrylic resin; however, this method still presents several limitations, including longer fabrication time, lower accuracy, and outcomes that are highly dependent on operator performance. The development of additive manufacturing technology offers several advantages, such as high reproducibility, improved accuracy in producing complex geometries, a more efficient digital workflow, and reduced material waste. This study investigated the effect of additive manufacturing using digital light processing (DLP) on the surface roughness and topography of denture bases fabricated with different printing layer thicknesses (50 μm and 100 μm), compared with conventional heat-cured acrylic resin bases. Disc-shaped samples with a diameter of 5 mm and a thickness of 2 mm were analyzed for surface roughness using a profilometer along a 2 mm straight line, while surface topography was observed using scanning electron microscopy (SEM). The results showed significant differences in surface roughness among the groups, where the additive manufacturing group with a 50 μm layer thickness exhibited the smoothest surface (0.96±0.26 μm), followed by the conventional heat-cured group (1.75±0.31 μm), while the additive manufacturing group with a 100 μm layer thickness showed the highest roughness value (4.27±0.55 μm). SEM analysis also revealed crater-like surface defects correlated with variations in layer thickness. These defects were observed more frequently in the additive manufacturing group with a 100 μm layer thickness compared with the 50 μm layer thickness group. These findings confirm the importance of additive manufacturing parameters in determining the final properties of denture bases and indicate the potential for optimizing fabrication techniques to achieve improved denture outcomes.
H.D. Septama; A. Erna Permanasari; R. Ferdiana
2026 IEEE International Conference on Industry 4.0, Artificial Intelligence, and Communications Technology (IAICT)
Year: 2026 | Conference Paper | Publisher: IEEE
N. Arina; I. Hidayah; N.A. Setiawan
2026 18th International Conference on Knowledge and Smart Technology (KST)
Year: 2026 | Conference Paper | Publisher: IEEE
M. Mustafirin; R. Ferdiana; N.A. Setiawan
SoutheastCon 2026
Year: 2026 | Conference Paper | Publisher: IEEE
M. Wahyudi; T. Tumiran; N.A. Setiawan
IEEE Access
Year: 2026 | Journal Article | Volume: 14 | Publisher: Institute of Electrical and Electronics Engineers (IEEE)
E. Firmansyah; R. Wicaksono
JURNAL INFOTEL
Year: 2025 | Journal Article | Volume: 17, Issue: 2 | Publisher: LPPM Institut Teknologi Telkom Purwokerto
Abstract: Electrical impedance tomography (EIT) supports recent advancements in gastric monitoring for telehealth applications. The challenge in providing low-cost EIT is ensuring a stable current injection over diverse tissue conductivities within the abdominal cavity. Three current source circuits based on Howland's current source are investigated to be applied in a low-cost portable bioimpedance analyzer (p-BIA). Those are: a) triple amplifier Howland current source (TAHCS), b) mirrored Howland current source (MHCS), and c) composite mirrored Howland current source (CMHCS). Evaluation has been conducted based on signal-to-noise ratio (SNR), broadness of the frequency range, and output impedance over frequency value and stability. Due to its high SNR value (82.56 to 102.1 dB), broad (500 Hz to 500 kHz) operating frequency, and consistent output impedance over operating frequency (10 to 25 kΩ), CMHCS is a good option in realizing p-BIA in gastric monitoring based EIT.
N.A. Salsabilla; R. Wicaksono; I. Ardiyanto
2025 IEEE International Biomedical Instrumentation and Technology Conference (IBITeC)
Year: 2025 | Conference Paper | Publisher: IEEE
E.D. Kusuma; R. Wicaksono; A.R. Pratama
2025 17th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2025 | Conference Paper | Publisher: IEEE
M.F.F. Abdigusna; R. Wicaksono; S. Wibirama
2025 1st International Conference on Data Science and Geoinformatics (ICDSG)
Year: 2025 | Conference Paper | Publisher: IEEE
R. Wicaksono; M.R. Baidillah; A.D. Baihaqi; D.D. Ritonga
Year: 2025 | Journal Article | Publisher: Elsevier BV
K.A. Nugraha; I. Ardiyanto; S. Wibirama
2025 17th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2025 | Conference Paper | Publisher: IEEE
A. Solaeman; S.A. Ishaq Alfarozi; S. Wibirama
2025 International Conference on Advancement in Data Science, E-learning and Information System (ICADEIS)
Year: 2025 | Conference Paper | Publisher: IEEE
R. Faurina; S. Wibirama; T.B. Adji
2025 5th International Conference on Intelligent Cybernetics Technology & Applications (ICICyTA)
Year: 2025 | Conference Paper | Publisher: IEEE
K.A. Nugraha; I. Ardiyanto; S. Wibirama
2025 5th International Conference on Intelligent Cybernetics Technology & Applications (ICICyTA)
Year: 2025 | Conference Paper | Publisher: IEEE
F.M. Ahsan; I. Ardiyanto; S. Wibirama
2025 1st International Conference on Data Science and Geoinformatics (ICDSG)
Year: 2025 | Conference Paper | Publisher: IEEE
M.D. Nashrullah; A. Sanata; I. Solahuddin; N. Ilminnafik; I. Pranoto; A. Widyaparaga
Journal of Mechanical Engineering Science and Technology (JMEST)
Year: 2025 | Journal Article | Volume: 9, Issue: 1 | Publisher: State University of Malang (UM)
Abstract: This study examined how surface roughness and nanoceramic coating, influences the boiling heat transfer coefficient (BHTC) and critical heat flux (CHF) of a conical cylindrical copper test specimen. Three test specimens exhibiting surface roughness of 0.22 µm, 0.14 µm, and 0.04 µm were analyzed for comparison. Two additional test specimens were treated with nanoceramic coatings utilizing silicon carbide as the base material: one specimen received a single-layer coating and the second was applied with a double-layer coating. The behavior of the bubbles was closely observed with a high-speed camera to deepen the analysis. The experimental results showed that the test specimen with higher surface roughness exhibited higher BHTC and CHF. The 0.22 µm surface roughness specimen demonstrated a 55.69% greater BHTC than the 0.04 µm surface roughness specimen. In contrast, the 0.04 µm surface roughness specimen had the lowest CHF, 426.09 kW/m². Nanoceramic coating also enhanced the BHTC and CHF. The specimen with a single-layer coating had the highest BHTC, 40.81% higher than the uncoated specimen. The specimen with a double-layer coating showed a 60.12% increase in CHF compared to the specimen with a single-layer coating. The bubble observation results indicated that test specimens with higher BHTC and CHF had more active nucleation sites. The quantity of active nucleation sites plays a vital role in producing a large number of bubbles, enhancing heat transfer, and maintaining the surface temperature.
F.T.D. Atmaji; Jamasri; H.A. Yuniarto; I. Made Miasa
Results in Engineering
Year: 2025 | Journal Article | Volume: 27 | Publisher: Elsevier BV
R. Riza; M. Mahardika; B. Arifvianto
2025 IEEE 23rd Student Conference on Research and Development (SCOReD)
Year: 2025 | Conference Paper | Publisher: IEEE
R. Riza; M. Mahardika; B. Arifvianto
Manufacturing Letters
Year: 2025 | Journal Article | Volume: 45 | Publisher: Elsevier BV
D.D. Rahmatika S; B. Arifvianto; R. Dharmastiti
Jurnal Teknosains
Year: 2025 | Journal Article | Volume: 14, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: A prototype of a single-axis prosthetic foot is proposed as an alternative prosthetic foot for patients with disabilities to perform daily activities. Three leading positions within 0-64% of the gait cycle are heel strike, midstance, and toe-off positions used as boundary conditions. The Finite Element Method can analyze a model to determine the values of deformation, stress, and strain that occur in detail. This research is conducted to fabricate an optimal prosthetic foot product or prototype and determine its strength to support the weight of the user's body and provide comfort and safety before being fabricated using 3D printing and resin infusion methods. The fabrication of the prosthetic foot prototype used Fusion 360 software and continued with simulation testing using ABAQUS 6.14 software. The prototype model was designed and evaluated to obtain strength and feasibility before being fabricated with an Anycubic Photon Mono X type DLP 3D printing machine and resin infusion method. The results obtained in this study show that the prototype of a single-axis prosthetic foot can support the human body's weight with loading level P3 or 60 kg, level P4 or 80 kg, and level P5 or 100 kg according to ISO 10328. The mass of the prototype or single-axis prosthetic foot product is 657 grams, according to the criteria, not more than 1.7% of the user's total body weight, with a hardness value of 55.5 HA, and can withstand 50,000 cycles in fatigue testing.
R.H. Widyatmoko; M. Mahardika; B. Arifvianto; A. Sugijopranoto
Advances in Engineering Research
Year: 2025 | Book Chapter | Publisher: Atlantis Press International BV
R.M. Paksi; R. Dharmastiti; D. Kuswanto; B. Arifvianto
AIP Conference Proceedings
Year: 2025 | Conference Paper | Volume: 3280 | Publisher: AIP Publishing
G. Bagaskara; B. Arifvianto; M. Mahardika; Z. Mao; A. Wiranata
Indonesian Journal of Computing, Engineering, and Design (IJoCED)
Year: 2025 | Journal Article | Volume: 7, Issue: 2 | Publisher: Sampoerna University - Faculty of Engineering and Technology
Abstract: This study aims to develop a Python and Gmsh-based program for automating the generation of finite element method (FEM) models and integration with the OpenRadioss solver, enabling more efficient creation of a FEM model for a curved corrugated sandwich structure under projectile impact. Based on the research conducted, the program has been successfully integrated with OpenRadioss and successfully simulated. The simulation results show a graph that closely matches experimental data, indicating that the generated finite element model is acceptable. The time required to generate the model is approximately ±73 s, while conventional methods require at least ±480 s. Additionally, this program has been compared with the latest Graphical User Interfaces (GUI) provided by OpenRadioss, demonstrating the advantages of the developed program in terms of time efficiency, ease of use, and its ability to handle design variations more quickly.
R. Setiyani; U.A. Salim; M. Mahardika; R. Dharmastiti; B. Arifvianto
Jurnal Teknosains
Year: 2025 | Journal Article | Volume: 14, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: The color of denture base material is important in dentistry to achieve a natural gingival aesthetic. No universal standard for denture base color, due to it difficult for dentists and dental laboratory technicians to achieve consistent results. This study proposes a method for identifying the color of artificial gums made from heated cure polymers with coloring agents. This study also examined the effect adding color agent on the hardness of denture base material and the effect of artificial saliva immersion on coloring. New coloring agents, namely pink (P), red (M), and purple (U), were added to create new colors in this study. Seven specimens from light to dark colors were made. The resulting specimens were photographed and analyzed using Adobe Photoshop software to obtain the L*, a*, and b* values for each specimen, which were then analyzed using the CIELAB formula. The results of the material hardness test showed a significant change between the immersion and non-immersion groups (p-value 0.00<0.05), while the group between 10-day and 20-day immersion showed no significant change (p-value 0.65>0.05). In materials without added color, the hardness value is 85.3 - 86.3 HSD, while in materials with added color, the hardness value increases to 85.5 - 87.7 HSD. The results of the saliva immersion test showed changes in the range of 2.51 - 5.98 for 10 days of immersion and 0.85 - 4.22 for 20 days of immersion. Based on these results, most of the color changes are still below the clinical acceptance threshold of less than 4.1. Therefore, it can be concluded that the color changes that occur after soaking are still clinically acceptable.
B.A.I. Kurnia; M. Mahardika; B. Arifvianto; V.L. Jauw
Advances in Engineering Research
Year: 2025 | Book Chapter | Publisher: Atlantis Press International BV
R.H. Widyatmoko; B. Arifvianto; A. Sugijopranoto; U.A. Salim; M. Mahardika
Progress in Additive Manufacturing
Year: 2025 | Journal Article | Volume: 11, Issue: 2 | Publisher: Springer Science and Business Media LLC
B.A.I. Kurnia; M. Mahardika; B. Arifvianto; V.L. Jauw
Advances in Engineering Research
Year: 2025 | Book Chapter | Publisher: Atlantis Press International BV
Y.V. Yoanita; I. Perdana; M.A. Muflikhun; B. Arifvianto; M. Mahardika
Year: 2025 | Journal Article | Publisher: Elsevier BV
M. Ikhlas; S.I. Cahyono; B.T. Prayoga; R. Dharmastiti; B. Arifvianto; M. Mahardika
IPTEK The Journal of Engineering
Year: 2025 | Journal Article | Volume: 11, Issue: 1 | Publisher: Lembaga Penelitian dan Pengabdian kepada Masyarakat ITS
Abstract: Up till now, denture has been widely used for resolving dental problems, especially those due to attrition. The attrition of tooth enamel could lead to wear and lowering the functions of normal teeth. So far, denture is made conventionally by using heat curing method in a mold. However, the complex geometries of teeth and oral cavity has led to the use of the more advanced techniques, such as additive manufacturing. In this research, the denture material fabricated by using digital light processing (DLP) additive manufacturing was studied in term of their liquid absorption capability and wear behavior. The specimen was printed with three build orientations, namely 0°/180°, 90°/90°, and 45°/135°. These are the degree between printing direction against sliding direction. An immersion and wear test were carried out in artificial saliva liquid. The result showed the lowest weight gain and dimensional change in the specimens printed with 90°/90° and 45°/135°. Meanwhile, the specimens prepared with build orientation of 0°/180° or printed with layer parallel to sliding direction demonstrated the smallest value of wear factor, indicating a better wear resistance compared to the others. A visual examination of the worn surface indicated delamination, abrasion and cracking as the possible wear mechanisms of the printed denture materials.
R. Fauzi; A.E. Permanasari; S. Fauziati
International Journal of Advanced Computer Science and Applications
Year: 2025 | Journal Article | Volume: 16, Issue: 8 | Publisher: The Science and Information Organization
H. Hendrik; S. Fauziati; A.E. Permanasari
JUCS - Journal of Universal Computer Science
Year: 2025 | Journal Article | Volume: 31, Issue: 5 | Publisher: Pensoft Publishers
Abstract: Knowledge graphs are a powerful way to represent and organize complex knowledge. They are used in many fields, like healthcare and finance. They allow for more insightful decision-making and discoveries. However, the quality of knowledge graphs depends heavily on their sources. Current methods for evaluating these sources are often slow and not scalable. They struggle to keep up with the large amount of online information. We created a new tool to address this problem. Our tool uses Large Language Models (LLMs) to assess online sources quickly. It evaluates websites based on credibility, relevance, content quality, coverage, comprehensiveness, and accessibility. We tested our tool on Halal tourism websites in Japan. We compared LLM evaluations with human expert judgments. Our comprehensive analysis revealed that certain LLM models, particularly GPT-3.5-turbo, GPT-4, and Mixtral-8x7B-Instruct-v0.1, showed strong correlation with human evaluations. Using a temperature setting of 0.4, these models demonstrated consistent and reliable performance across multiple evaluation runs. Our structured evaluation framework, incorporating weighted criteria validated through both expert input and statistical analysis, provides a robust foundation for automated source assessment. While some models showed varying performance across different criteria, our findings suggest that careful model selection and potential ensemble approaches could optimize evaluation accuracy. Our work contributes significantly to improving knowledge graph construction by demonstrating the viability of LLM-based source evaluation, while also identifying key areas for future research in scalability, cross-domain validation, and automated optimization.
S. Diwandari; A.E. Permanasari; I. Hidayah
2025 International Conference on Advanced Machine Learning and Data Science (AMLDS)
Year: 2025 | Conference Paper | Publisher: IEEE
H. Hendrik; S. Fauziati; A.E. Permanasari
2025 IEEE 14th International Workshop on Computational Intelligence and Applications (IWCIA)
Year: 2025 | Conference Paper | Publisher: IEEE
S. Aminah; I. Hidayah; A.E. Permanasari
2025 IEEE International Conference on Artificial Intelligence and Mechatronics Systems (AIMS)
Year: 2025 | Conference Paper | Publisher: IEEE
D. Wicaksono; A.E. Permanasari; S. Fauziati
Atlantis Highlights in Sustainable Development
Year: 2025 | Book Chapter | Publisher: Atlantis Press International BV
E. Tjandra; N.A. Setiawan
2025 17th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2025 | Conference Paper | Publisher: IEEE
A. Imron; N. Akhmad Setiawan
2025 IEEE International Conference on Artificial Intelligence for Learning and Optimization (ICoAILO)
Year: 2025 | Conference Paper | Publisher: IEEE
N. Arina; I. Hidayah; N.A. Setiawan
2025 8th International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2025 | Conference Paper | Publisher: IEEE
M. Mustafirin; R. Ferdiana; N.A. Setiawan
2025 5th International Conference on Electronic and Electrical Engineering and Intelligent System (ICE3IS)
Year: 2025 | Conference Paper | Publisher: IEEE
F.C. Permana; S. Wibirama; N.A. Setiawan
2025 11th International HCI and UX Conference in Indonesia (CHIuXiD)
Year: 2025 | Conference Paper | Publisher: IEEE
F. Chefana Aulya; P. Mulyono; A. Prasetya
Proceedings National Conference Sinesia
Year: 2025 | Journal Article | Volume: 1, Issue: 2 | Publisher: Yayasan Penelitian dan Pengabdian Masyarakat Sisi Indonesia
Abstract: Red mud merupakan residu dari proses Bayer dengan pH sangat tinggi (11–13) yang berpotensi menimbulkan pencemaran lingkungan. Meskipun demikian, red mud mengandung logam bernilai seperti Fe, Ti, dan unsur tanah jarang (REE), sehingga berpeluang dimanfaatkan melalui fitomining. Penelitian ini mengkaji kemampuan tanaman Vetiver (Chrysopogon zizanioides) dalam mengakumulasi logam serta memperbaiki kualitas media melalui fitoremediasi. Metodologi Response Surface Methodology (RSM) menggunakan Design Expert diterapkan untuk menganalisis pengaruh asam fosfat, asam humat, dan pupuk NPK Mutiara 16-16-16 terhadap respons utama yaitu penurunan pH red mud. Berdasarkan hasil percobaan, penurunan pH berlangsung efektif hingga berada pada rentang 6,5 – 6,8, sehingga kondisi media lebih mendukung pertumbuhan akar dan ketersediaan logam bagi tanaman. Vetiver menunjukkan pertumbuhan stabil pada media yang telah diberi perlakuan dan mampu mengakumulasi logam terutama pada bagian akar. Oleh karena itu, sistem fitoremediasi–fitomining berbasis Vetiver berpotensi diterapkan sebagai solusi pengelolaan red mud yang lebih ramah lingkungan.
D.P. Wenael; M.M. Aziz; P. Mulyono
Advances in Engineering Research
Year: 2025 | Book Chapter | Publisher: Atlantis Press International BV
G. Winoto; P. Mulyono; S. Suyanti; A. Prasetya
Indonesian Journal of Chemistry
Year: 2025 | Journal Article | Volume: 25, Issue: 4 | Publisher: Universitas Gadjah Mada
Abstract: Rare earth elements (REEs) are chemical elements in the III B and lanthanide groups on the chemical periodic table. Extracting REEs from secondary resources (such as coal fly ash) could be environmentally friendlier than extracting REEs from primary resources. Coal fly ash was chosen because of its attractive REE availability and to minimize the pollution problem created by coal fly ash dumping. Citric acid is used as the leaching agent because of its biodegradability, relatively safe vis-à-vis mineral acid commonly used in the REE leaching, and its non-damaging nature to coal fly ash’s properties as construction material. The leaching experiment was conducted at temperature variations of 30, 50, and 85 °C, with liquid-solid ratio (L/S) of 5, 10, and 15 mL/g in 50 mL of 0.01 mol/L citric acid solution. The leaching experiments were conducted in a water bath shaker. It was found that increasing L/S and temperature mainly contributed to increasing cerium leaching capacity.
G.L. Hakim; A. Prasetya; P. Mulyono; H.T.B.M. Petrus
BIS Health and Environmental Science
Year: 2025 | Journal Article | Volume: 2 | Publisher: Universitas Muhammadiyah Magelang
Abstract: As industrialization accelerates, the demand for metals, particularly aluminium, continues to rise. This growth has also led to an increase in by-products from the bauxite ore refining process, namely red mud. The highly alkaline nature of red mud, combined with its heavy metal content, poses significant environmental challenges. However, red mud also contains rare earth elements (REEs) that can serve as valuable secondary resources. An environmentally friendly approach to recovering these metals is phytomining, which utilizes plants and simultaneously contributes to land remediation. This study aims to evaluate the potential of Imperata cylindrica in metal recovery and the remediation of red mud waste. The research began by conditioning the pH of red mud through the addition of citric acid, fertilizers, and by adjusting the red mud composition to levels of 40% based on the optimum result using Response Surface Methodology. Phytomining was initiated once the pH of the substrate (a mixture of red mud and soil) reached an optimal range of 8.0–8.5. The results demonstrated that Imperata cylindrica was capable of absorbing several rare earth metals, including gadolinium (Gd), neodymium (Nd), and cerium (Ce), with concentrations of 119.5 mg/kg, 16.5 mg/kg, and 6.67 mg/kg, respectively, in its roots. Additionally, the plant showed the ability to absorb major components such as iron (Fe) and titanium (Ti), with the metals distributed throughout the plant's roots, stems, and leaves.
R.L.B. Wicaksono; A.D.V. Rohman
International Journal of Global Operations Research
Year: 2024 | Journal Article | Volume: 5, Issue: 4 | Publisher: Indonesian Operations Research Association
Abstract: Insurance fraud, particularly in the automobile sector, poses significant financial risks to insurance companies. This study aims to analyze fraudulent claims in automobile insurance using Decision Tree and Random Forest methods. A dataset consisting of 10,000 entries was utilized, containing variables such as vehicle type, claim amount, and claim status. The Decision Tree method was employed for its interpretability, while Random Forest was used for its superior accuracy. Results indicated that the Random Forest model outperformed the Decision Tree model, achieving an accuracy of 51.37% compared to 50.47%. This research highlights the effectiveness of machine learning techniques in detecting insurance fraud and provides insights for insurers to enhance their fraud detection systems.
A.D. Baihaqi; R. Wicaksono; A.I. Cahyadi
2024 5th International Conference on Biomedical Engineering (IBIOMED)
Year: 2024 | Conference Paper | Publisher: IEEE
K.A. Ibrahim; M.R. Baidillah; R. Wicaksono; S. Akita; M. Takei
IEEE Transactions on Instrumentation and Measurement
Year: 2024 | Journal Article | Volume: 73 | Publisher: Institute of Electrical and Electronics Engineers (IEEE)
R.W. Apriliani; S. Wibirama
2024 7th International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2024 | Conference Paper | Publisher: IEEE
I. Mustamir; A. Nasikun; S. Wibirama
2024 16th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2024 | Conference Paper | Publisher: IEEE
S. Arizi; N.A. Setiawan; S. Wibirama
2024 IEEE International Conference on Artificial Intelligence and Mechatronics Systems (AIMS)
Year: 2024 | Conference Paper | Publisher: IEEE
A.H. Fathiya; A. Nasikun; S. Wibirama
2024 5th International Conference on Biomedical Engineering (IBIOMED)
Year: 2024 | Conference Paper | Publisher: IEEE
N.F. Qinthari; S. Wibirama; R. Ferdiana
2024 2nd International Symposium on Information Technology and Digital Innovation (ISITDI)
Year: 2024 | Conference Paper | Publisher: IEEE
Sucipto; I.M. Miasa; A. Widyaparaga
AIP Conference Proceedings
Year: 2024 | Conference Paper | Volume: 3220 | Publisher: AIP Publishing
P. Murti; E.Y. Putro; A. Widyaparaga; I. Setiawan; W.D. Astuti
2024 2nd International Conference on Power and Renewable Energy Engineering (PREE)
Year: 2024 | Conference Paper | Publisher: IEEE
B. Febrinawarta; I.M. Miasa; A. Widyaparaga; S. Sucipto; W.D. Premiaji
Journal of Engineering and Applied Technology
Year: 2024 | Journal Article | Volume: 5, Issue: 1 | Publisher: Universitas Negeri Yogyakarta
Abstract: In our environment, acoustic sound waves transform into undesirable noise when their intensity exceeds 100 dB, prompting a need for effective mitigation strategies. In recent years, there has been increasing interest in utilising sound/noise and acoustics for energy harvesting, especially for low-power electronic devices committed to clean renewable energy sources. Metamaterials, with a spotlight on metalens, are emerging as a promising solution for precise sound focusing and energy conservation. This study delves into the intricate process of fabricating metalens through Stereolithography (SLA) 3D printing, unravelling their acoustic focusing capabilities. Metalenses, equipped with intricately designed labyrinthine unit cells tailored for manipulating reflected wave phases, materialize through the precision of SLA 3D printing, forming a sophisticated multilateral structure. The experimental framework for acoustic focusing integrates essential components such as a waveguide, speaker array, metalens, acoustic foam, and a sound level meter. The resultant metalens, composed of 22-unit cells with diverse dimensions, distinctly demonstrate robust acoustic focusing capabilities. Calibration procedures are systematically applied to ensure uniformity of speaker array output and to create a carefully controlled acoustic environment. Sound level measurements clearly depict zones of mutually reinforcing resonance heights, while, conversely, there are also zones of mutually attenuating sound. The complex interplay of sound waves through the metalens, intricately guided by the design of the unit cells, decisively determines the degree of acoustic focus achieved. The SLA 3D printed metalens emerges as a compelling manifestation of effective sound concentration, poised for potential applications in the realm of acoustic energy harvesting. Nevertheless, the study's consequential findings beckon further scientific exploration, prompting an in-depth comprehension of the nuanced impacts of input frequency and potential heating phenomena.
B. Arifvianto; C. Irawan; S. Suyitno; U.A. Salim; M. Mahardika
Applied Mechanics and Materials
Year: 2024 | Journal Article | Volume: 920 | Publisher: Trans Tech Publications, Ltd.
Abstract: Fused filament fabrication (FFF) has nowadays become a popular 3-dimensional (3D) printing technique for the fabrication of polymeric components with customized and complex-shape design, including biomedical implants. However, the use of this technique is often constrained by the limited number of polymeric materials that can be printed to form the final product. Despite excellent wear resistance and widely used as the acetabular component of a joint prosthesis, ultra-high molecular weight polyethylene (UHMWPE) is among such the rarely-found filament material in the market. In this research, preliminary work to fabricate UHMWPE filament for the FFF processing is carried out by using extrusion. The influences of extrusion temperature, addition of polyethylene glycol (PEG), and rotational speed of the extruder’s screw on the physical, chemical, and mechanical properties of the extruded UHMWPE filament were determined. The result demonstrated no change in the chemical compositions of the filament due to the processing parameters applied, as noted from the FTIR spectra. The result of the tensile test showed that the highest tensile strength of UHMWPE filaments could reach 23.5 MPa.
K. Rajagukguk; S. Suyitno; H. Saptoadi; I.K.I. Kusumaningtyas; B. Arifvianto; M. Mahardika
Archives of Foundry Engineering
Year: 2024 | Journal Article | Publisher: Polish Academy of Sciences Chancellery
Abstract: An as-cast aluminum billet with a diameter of 100 mm has been successfully prepared from aluminum scrap by using direct chill (DC) casting method. This study aims to investigate the microstructure and mechanical properties of such as-cast billets. Four locations along a cross-section of the as-cast billet radius were evaluated. The results show that the structures of the as-cast billet are a thin layer of coarse columnar grains at the solidified shell, feathery grains at the half radius of the billet, and coarse equiaxed grains at the billet center. The grain size tends to decrease from the center to the surface of the as-cast billet. The ultimate tensile strength (UTS) and the hardness values obtained from this research slightly increase from the center to the surface of the as-cast billet. The distribution of Mg, Fe, and Si elements over the cross-section of the as-cast billet is inhomogeneous. The segregation analysis shows that Si has negative segregation towards the surface, positive segregation at the middle, and negative segregation at the center of the as-cast billet. On the other hand, the Mg element is distributed uniformly in small quantities in the cross-section of the as-cast billet.
K. Rajagukguk; S. Suyitno; H. Saptoadi; I. Kusumaningtyas; U.A. Salim; B. Arifvianto; M. Mahardika
Applied Mechanics and Materials
Year: 2024 | Journal Article | Volume: 918 | Publisher: Trans Tech Publications, Ltd.
Abstract: Direct chill (DC) casting has been considered as one of the promising casting methods that can be used to produce aluminum alloys billet. The process is conducted by pouring aluminum metal into a water-cooled mold. The billet shell begins to form when molten aluminum contact directly with the mold (this is also known as primary cooling). Afterward, the starting block is pulled downwards at a specified casting speed to achieve desired aluminum billet. The start-up phase during the DC casting process is considered a crucial step since it may determine the formation of defects in the casting products. This research aims to investigate the casting defects on the aluminum alloy that were formed during the start-up process of DC casting. The results show that the billet failed to form following the downward movement of starting block. Meanwhile, the billet tended to stick to the mold wall due to several factors, such as too low a pouring temperature, a less-round mold shape, the poor quality of the hot top and graphite ring, and the water that entered the mold during the casting process. It also noted several markers of the casting defects that occurred during the DC casting process such as liquation or bleeding, cold folding, billet stuck in the mold, butt structure, and rough billet surface.
B. Arifvianto; M.J. Abdullah; R. Dharmastiti; S. Suyitno; U.A. Salim; M. Mahardika
Journal of Fibers and Polymer Composites
Year: 2024 | Journal Article | Volume: 3, Issue: 1 | Publisher: Green Engineering Society
Abstract: In recent decades, ultra-high molecular weight polyethylene (UHMWPE) has gained recognition and widespread utilization as an outstanding polymeric biomaterial for load-bearing components in artificial joints. Despite its promise, this material presents challenges in processing with additive manufacturing techniques. Efforts have been underway to investigate and enhance its printability with the additive manufacturing, aiming to facilitate the production of patient-specific implants. This study aims to prepare UHMWPE-based filament through extrusion and subsequently print it with fused filament fabrication (FFF) 3-dimensional (3D) printer to create a simple rectangular sheet. Characterizations by using Fourier-transform infra-red (FTIR) spectroscopy and differential scanning calorimetry (DSC) were conducted to assess the chemical compositions and thermal properties of the UHMWPE filament and its printed forms. The findings of this research demonstrate the feasibility of printing UHMWPE filament filament within the temperature range of 200 - 240 °C. Analysis of the FTIR and DSC spectra reveals no evidence of impurities introduced during the preparation and printing processes that could alter its properties.
A.Z. Adib; J. Pratama; U.A. Salim; S. Suyitno; M. Mahardika; B. Arifvianto
Applied Mechanics and Materials
Year: 2024 | Journal Article | Volume: 920 | Publisher: Trans Tech Publications, Ltd.
Abstract: Fused Filament Fabrication (FFF) continues to experience improvements in terms of its flexibility and functionality, therefore it attracts public attention to use this technology. Multi-Material Additive Manufacturing (MMAM) is an approach in the FFF technology that allows the manufacturing of 3D-printed products composed of two or more materials in a single printing process. MMAM enables the user to apply various configurations to obtain a 3D-printed material with adjustable properties. This study aims to determine the effect of core material on the Shore hardness of the FFF printed parts with the MMAM approach. There were two types of materials combined with the MMAM approach in this work, namely polylactic-acid (PLA) and thermoplastic elastomer (TPE). The Shore hardness test was conducted according to the ASTM D2240-15 standard. The results showed that the thickness of the core material inserted into the printed material had a significant effect on the hardness value of printed multi-material parts. In addition, the hardness value was highly dependent on the modulus of elasticity of the material. Therefore, the hardness value changed following the proportion of the printed material.
M.I. Badranaya; J. Pratama; U.A. Salim; S. Suyitno; B. Arifvianto; M. Mahardika
Applied Mechanics and Materials
Year: 2024 | Journal Article | Volume: 918 | Publisher: Trans Tech Publications, Ltd.
Abstract: A comprehensive understanding of powder flow is essential, particularly in the synthesis of additives in the solid free-forming process and dosage dispensing in pharmaceutical industries. The vibration method is the most widely used for inducing powder flow. In this method, a hopper containing powder is vibrated by a piezoelectric system to allow powder flow. However, there are several drawbacks in this method, particularly in the degree of consistency of the resulting flow. This occurs because the vibration characteristics created have a single axis direction, resulting in which can lead to powder compaction. To resolve this problem, this research is conducted to determine the flow properties of titanium powder dispensed by 2-axis vibration. The titanium (Ti) powder having a size of less than 74 μm in the powder hopper was vibrated for 15 min by a DC motor and the weight of the dispensed powder was measured to evaluate the consistency of the resulting powder flow. The result shows that the powder flow generated by the DC motor was consistent during the period of dispensing. However, the powder flow rate dropped up to 8.6% during 5-10 min of dispensing at a speed of 1800 rpm. In conclusion, the 2-axis vibration by using a DC motor could prevent the powder compacting phenomenon and ensure a consistent flow of micro-sized powders during the dispensing process.
C.P. Wardoyo; M. Mahardika; S. Suyitno; R. Dharmastiti; U.A. Salim; B. Arifvianto
Jurnal Rekayasa Mesin
Year: 2024 | Journal Article | Volume: 15, Issue: 3 | Publisher: Brawijaya University
Abstract: Along with the increasing number of persons with disabilities, the need for prosthetic foot has also increased. However, the irony is that some of the products circulating in Indonesia are still imported from abroad, while the domestic product is quite limited and possesses some drawbacks. This study aims to study the production process of the single axis type of the right-side prosthetic foot as well as to evaluate the performance of this product. The prosthetic foot in this research was made from thermoplastic polyurethane (TPU) resin and prepared with casting by pouring it into a pre-fabricated mold. A single-axis type of right prosthetic product could have been successfully made in this study with men's shoe sizes EU 42 and a mass of 654 g. The result of evaluation of the material and foot prosthetic product showed an average Shore hardness value of 54.3 HA. According to the result of compression test, this prosthetic product was also able withstand the highest compressive load up to 259.76 kgf. Finally, the result of fatigue test showed no damage on the foot prosthetic product until 90.000 cycle.
T. Sriani; M. Mahardika; B. Arifvianto; F. Yusof; Y. Whulanza; G.S. Prihandana; A.S. Baskoro
Polymers
Year: 2024 | Journal Article | Volume: 16, Issue: 21 | Publisher: MDPI AG
Abstract: Polysulfone (Psf) ultrafiltration flat-sheet membranes were modified with hydroxyapatite (HA) powder during preparation using the wet-phase inversion method. HA was incorporated to enhance the protein separation capabilities. The asymmetric Psf membranes were synthesized using NMP as the solvent. Through Scanning Electron Microscopy (SEM) analysis, it was revealed that HA was distributed across the membrane. Incorporating HA led to higher flux, the improved rejection of protein, and enhanced surface hydrophilicity. The permeability flux increased with HA concentration, peaking at 0.3 wt.%, resulting in a 38% improvement to 65 LMH/bar. Whey protein separation was evaluated using the model proteins BSA and lysozyme, representing α-Lactalbumin. The results of protein rejection for the blend membranes indicated that the rejection rates for BSA and lysozyme increased to 97.2% and 73%, respectively. Both the native and blend membranes showed similar BSA rejection rates; however, the blend membranes demonstrated better performance in lysozyme separation, indicating superior selectivity compared to native membranes. The modified membranes exhibited improved hydrophilicity, with water contact angles decreasing from 66° to 53°, alongside improved antifouling properties, indicated by a lower flux decline ratio value. This simple and economical modification method enhances permeability without sacrificing separation efficiency, hence facilitating the scalability of membrane production in the whey protein separation industry.
R. Fauzi; A.E. Permanasari; S. Fauziati
2024 8th International Conference on Information Technology (InCIT)
Year: 2024 | Conference Paper | Publisher: IEEE
Y. Hartika; A.E. Permanasari; S. Fauziati
2024 2nd International Symposium on Information Technology and Digital Innovation (ISITDI)
Year: 2024 | Conference Paper | Publisher: IEEE
S. Diwandari; A.E. Permanasari; I. Hidayah
2024 8th International Conference on Information Technology (InCIT)
Year: 2024 | Conference Paper | Publisher: IEEE
A. Hanifa; A.E. Permanasari; I. Hidayah
2024 5th International Conference on Biomedical Engineering (IBIOMED)
Year: 2024 | Conference Paper | Publisher: IEEE
E. Tjandra; R. Ferdiana; N.A. Setiawan
2024 International Conference on Intelligent Cybernetics Technology & Applications (ICICyTA)
Year: 2024 | Conference Paper | Publisher: IEEE
S. Murnani; N.A. Setiawan; S. Wibirama
IEEE Transactions on Human-Machine Systems
Year: 2024 | Journal Article | Volume: 54, Issue: 5 | Publisher: Institute of Electrical and Electronics Engineers (IEEE)
M.G. Pratama; N.A. Setiawan; R. Ferdiana
2024 10th International Conference on Communication and Signal Processing (ICCSP)
Year: 2024 | Conference Paper | Publisher: IEEE
A. Syaefudin; N.A. Setiawan; M.N. Rizal
2024 International Conference on Smart Computing, IoT and Machine Learning (SIML)
Year: 2024 | Conference Paper | Publisher: IEEE
A. Arham; H.A. Nugroho
Cybersecurity
Year: 2024 | Journal Article | Volume: 7, Issue: 1 | Publisher: Springer Science and Business Media LLC
Abstract: AbstractThe rapid growth of Information and communication technology not only has positive impacts but also unveils opportunities for data and information security threats. In recent years, many researchers have worked on developing methods to enhance data security, particularly through data hiding techniques aimed at safeguarding communications by concealing their existence. With the same objective in mind, this study introduces a novel method for Reversible Data Hiding (RDH) based on a combination of difference expansion (DE) and a modulus function. Our method enables the embedding of 3-bit data into 2-bit Least Significant Bit (LSB) difference values of pixel pairs formed in rectangular blocks. Based on the experimental results, the payload capacity of our method can reach 0.3953 bpp with a PSNR of 53.5900 dB on common images and 0.5764 bpp with a PSNR of 52.9234 dB on medical images. Our method consistently achieves high payload capacity with good visual quality, and our method surpasses previous approaches in terms of performance, payload capacity, and visual quality.
A. Arham; H. Adi Nugroho
Communications in Science and Technology
Year: 2024 | Journal Article | Volume: 9, Issue: 1 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
Abstract: In recent years, reversible watermarking has emerged as a promising technique that safely embeds data in digital images without compromising their originality. This method is particularly useful for sensitive images such as military, art, and medical images, where each pixel contains important information requiring authentication. Researchers have been attempting to develop this method further to increase payload capacity while maintaining visual quality and low computational complexity. In this study, we developed a reversible watermarking with block-based optimization based on Reduced Difference Expansion (RDE) applied to 3×3 pixel blocks, allowing for the embedding of 8?bit data. Based on experimental results from tests conducted on 2 common images and 3 medical images, our method could consistently achieve a payload capacity of up to 0.8924 bpp with a PSNR of 41.077 dB while maintaining good visual quality across various image categories, outperforming previous approaches.
Y. Rahmawati; I. Ardiyanto; H.A. Nugroho
2024 IEEE International Conference on Artificial Intelligence and Mechatronics Systems (AIMS)
Year: 2024 | Conference Paper | Publisher: IEEE
I. Darmiyati; I. Soesanti; H.A. Nugroho
2024 7th International Conference on Informatics and Computational Sciences (ICICoS)
Year: 2024 | Conference Paper | Publisher: IEEE
N. Jayanti; Nazarudin; P. Mulyono
ASEAN Journal of Chemical Engineering
Year: 2024 | Journal Article | Volume: 24, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: Abstract. One of the Oily Sludge (OS) recycling methods is through catalytic cracking. This process involves the reaction breaking down large molecules into smaller ones with the help of a catalyst. Nickel (Ni) metal is often used as a catalyst because it can increase fuel liquid yield while reducing the coke formation. To enhance its performance, Ni metal can be embedded in a carrier material like Silica to form the Ni-Silica catalyst. In this research, OS sourced from a Gas Process Plant is treated with catalytic cracking using Ni-Silica, where the Silica used is derived from an Adsorbent activated with NaOH. Optimization of the cracking conditions is carried out using Response Surface Methodology (RSM) with a Box-Behnken design. The optimized cracking reaction conditions include temperature (713 K, 723 K, and 733 K), time (50 min, 60 min, and 70 min), and catalyst-to-OS ratio of 1:5, 1:6, and 1:7. Statistical analysis indicates that the relationship between the reaction condition variables and the Oil Liquid Product (OLP) falls into the moderate category, as shown by the coefficient of determination (R²) of 0.5. The calculated F-value for the deviation from the mathematical model is smaller than the F-Table value (9.2) at both 5% and 1% significance levels, with a value of 0.6. This indicates that the mathematical model generated can be accepted as the mathematical model within the range of reaction conditions in this study. Calculus analysis reveals that the optimum reaction conditions are a temperature of 717.34 K, a time of 58.58 min, and a catalyst-to-OS ratio of 1:6, 15. Canonical analysis indicates that for OLP, λ1= [-12.38], λ2= [-2.27], and λ3= [4.50], where lambda values indicate that the most sensitive response surface parameter for OLP is temperature, followed by the catalyst-to-sample ratio, and the least sensitive is reaction time.
Keywords: Catalytic Cracking, Ni Metal, OS, RSM, Silica
G. Prameswara; I. Trisnawati; P. Mulyono; A. Prasetya; H.T.B.M. Petrus
Transition Metal Chemistry
Year: 2024 | Journal Article | Volume: 50, Issue: 1 | Publisher: Springer Science and Business Media LLC
K.A. Ibrahim; M.R. Baidillah; R. Wicaksono; M. Takei
Journal of Electrical Bioimpedance
Year: 2023 | Journal Article | Volume: 14, Issue: 1 | Publisher: Walter de Gruyter GmbH
Abstract: Abstract
Conductivity change in skin layers has been classified by source indicator
o
k
(
k
=1: Stratum corneum,
k
=2: Epidermis,
k
=3: Dermis,
k
=4: Fat, and
k
=5: Stratum corneum + Epidermis) trained from feedforward neural network (FNN) in bioelectrical impedance spectroscopy (BIS). In BIS studies, treating the skin as a bulk, limits the differentiation of conductivity changes in individual skin layers, however skin layer classification using FNN shows promise in accurately categorizing skin layers, which is essential for predicting source indicators
o
k
and initiating skin dielectric characteristics diagnosis. The
o
k
is trained by three main conceptual points which are (i) implementing FNN for predicting
k
in conductivity change, (ii) profiling four impedance inputs
α
ξ
consisting of magnitude input
α
|
z
|, phase angle input
α
θ
, resistance input
α
R
, and reactance input
α
x
for filtering nonessential input, and (iii) selecting low and high frequency pair
(
f
r
l
h
)
$$(f_{r}^{lh})$$
by distribution of relaxation time (DRT) for eliminating parasitic noise effect. The training data set of FNN is generated to obtain the
α
ξ
∈
R
10×17×10
by 10,200 cases by simulation under configuration and measurement parameters. The trained skin layer classification is validated through experiments with porcine skin under various sodium chloride (NaCl) solutions
C
NaCl
= {15, 20, 25, 30, 35}[mM] in the dermis layer. FNN successfully classified conductivity change in the dermis layer from experiment with accuracy of 90.6% for the bipolar set-up at
f
6
l
h
=
10
&
100
[
kHz]
$$f_{6}^{lh}=10\,\And 100\,{\rm{[kHz]}}$$
and with the same accuracy for the tetrapolar at
f
8
l
h
=
35
&
100
[
kHz]
$$f_{8}^{lh}=35\,\And 100\,{\rm{[kHz]}}$$
. The measurement noise and systematic error in the experimental results are minimized by the proposed method using the feature extraction based on
α
ξ
at
f
r
l
h
$$f_{r}^{lh}$$
.
K.A. Ibrahim; R. Wicaksono; M.R. Baidillah; K. Ito; M. Takei
Biomedical Physics & Engineering Express
Year: 2023 | Journal Article | Volume: 9, Issue: 5 | Publisher: IOP Publishing
Abstract: Abstract
Free and bound sodium in human skin models have been identified by two proposals: skin’s phantom fabrication and skin’s dielectric properties separation algorithm of bioelectrical impedance spectroscopy (spa-BIS). The spa-BIS consist of conductivity-permittivity separation, contact impedance compensation, and a correlation score algorithm based on the vessel with a bipolar electrode. The skin phantom fabrication comprises a recipe combination with temperature-controlled protocol and sodium molarity calculation. In experiments, the human skin models are created to mimic the electrical properties of skin under
1
MHz
with several different sodium molarities. Based on five types of human skin models with five samples of each group, the free sodium type conductivity and concentration results
R
2
=
0.9903
−
following a linear trendline of concentration change in skin tissues theorems with the fRequency range from
1
kHz
to
1
MHz
,
while the bound sodium type results
R
2
=
0.9061
−
.
The spa-BIS compensate
7
−
16
Ω
of vessel contact impedance. The dielectric properties of each type have been extracted with less than 10% of the average standard deviation, which is considered an accurate identification method of dermis dielectric properties. The algorithm successfully identifies sodium type: free sodium has a negative, and bound sodium has a positive correlation score trend. As an additional discussion, the different time-dependent effects, the different water content, and different agar content analyses have been provided in this study. As a robust analysis method, the spa-BIS has a prominent performance to replace a 23Na-MRI in terms of free and bound sodium identification.
I.N. Rifai; M.R. Baidillah; R. Wicaksono; S. Akita; M. Takei
Biomedical Physics & Engineering Express
Year: 2023 | Journal Article | Volume: 9, Issue: 4 | Publisher: IOP Publishing
Abstract: Abstract
In this study, sodium concentration in the dermis layer is imaged by the square wave open electrical impedance tomography (SW-oEIT) with spatial voltage thresholding (SVT). The SW-oEIT with SVT consists of three steps which are (1) voltage measurement, (2) spatial voltage thresholding, and (3) sodium concentration imaging. In the 1st step, the root mean square voltage
v
̃
is calculated based on the measured voltage
v
under the square wave current
I
through the planar electrodes on the skin domain Ω. In the 2nd step, the m-th measured voltage
v
is converted to a compensated voltage v
* based on the voltage electrodes distance
d
v
and threshold distance
d
Γ
in order to highlight the region of interest of the dermis layer
Ω
d
.
In the 3rd step, sodium concentration is imaged by the Gauss-Newton reconstruction method. The SW-oEIT with SVT was applied to multi-layer skin simulation and ex-vivo experiments under various dermis sodium concentrations c in the range of 5–50 mM. As an image evaluation result, the spatial mean conductivity distribution
σ
*
in
Ω
d
is successfully determined as increasing c on both simulations and experiments. The relationship between
〈
σ
*
〉
and c was evaluated by the determination coefficient R
2 and the normalized sensitivity
〈
S
〉
.
The optimized
d
Γ
with the highest evaluation values of
R
2
=
0.84 and
〈
S
〉
=
0.83 is under the condition of
d
Γ
= 2 mm. Based on the signal evaluation, the SW-oEIT with SVT has a 15.32% higher correlation coefficient CC compared to the conventional oEIT based on sinewave injection.
I.N. Rifai; M.R. Baidillah; R. Wicaksono; S. Akita; M. Takei
Measurement Science and Technology
Year: 2023 | Journal Article | Volume: 34, Issue: 7 | Publisher: IOP Publishing
Abstract: Abstract
Assessing dermis sodium concentration in skin is essential since an excessive amount of sodium is associated with vascular function disorders. In this research, dermis sodium concentration
c
has been quantified by the power spectral density drop
Δ
P
of square-wave electrical impedance spectroscopy (PSDd-sEIS). PSDd-sEIS is composed of three stages: (1) dermis voltage measurement, (2) PSDd calculation, and (3) dermis sodium quantification. In the 1st stage, three electrodes are arranged to measure voltage
v
under the constant current
I
of square-wave. In the 2nd stage,
Δ
P
is evaluated by the first and third harmonic frequency from
v
. In the 3rd stage,
c
is quantified by the developed linear regression. To obtain the highest sensitivity between c and
Δ
P
,
four measurement factors (square-wave frequency
f
sw
,
duty-cycle
γ
, electrode distance d, and electrode diameter ø) were optimized using numerical simulations of a skin model. Experiments on multi-layered skin under various c in the range of 5 nM–50 mM were conducted by PSDd-sEIS hardware with optimized measurement factors of
f
sw
∗
=
100
kHz
,
γ
∗
=
50
%
,
d
∗
=
2
mm
, and
ϕ
∗
=
0.8
mm
. As the results, the quantification of c has a good accuracy with the normalized sensitivity
⟨
S
⟩
=0.87 and determination coefficient R2
= 0.92. The measurement factors of
f
sw
and
γ
affect the power of square-wave excitation to pass through the high resistivity barrier of the stratum corneum, while the measurement factors of d and ø affect the stability of current flow in the dermis.
A. Damayanti; S.S. Kusumawardani; S. Wibirama
2023 IEEE 12th International Conference on Engineering Education (ICEED)
Year: 2023 | Conference Paper | Publisher: IEEE
A.R. Suhari; R. Hartanto; S. Wibirama
2023 International Conference on Advanced Mechatronics, Intelligent Manufacture and Industrial Automation (ICAMIMIA)
Year: 2023 | Conference Paper | Publisher: IEEE
H. Sudibyo; D.V. Cabrera; A. Widyaparaga; B. Budhijanto; C. Celis; R. Labatut
Industrial & Engineering Chemistry Research
Year: 2023 | Journal Article | Volume: 62, Issue: 32 | Publisher: American Chemical Society (ACS)
M. Mahardika; Y. Kurniawan; S. -; M.H. Amrullah; B. Arifvianto
Jurnal Teknologi
Year: 2023 | Journal Article | Volume: 86, Issue: 1 | Publisher: Penerbit UTM Press
Abstract: Recently, punching technology has become one of the promising manufacturing techniques for a thin metallic sheet. The processing parameters used in this technique have been recognized to influence the hole shape produced in the working materials. Therefore, it is important to understand the effect of the punching process parameters on the hole shape and quality over the manufactured materials. This study aims to determine the influence of the punching process on the non-symmetrical hole shape and quality over a commercially pure titanium sheet. The effect of punch speed on the punch force and the sheared surface is also studied, by applying the punch velocities of 10, 35 and 70 mm/s. The sheared surface of the hole was examined at its four different sides, namely K (straight), L (outer radius), N (inner radius) and M (straight). The results show uneven distribution of punch strength as detected at the affected region of the non-symmetrical hole. In addition, the punch force increased with the increase of punch speed. Meanwhile, the sheared surfaces on each side were apparently different. The burnish height on the side of the radius was found to be about 0.038 mm higher than that on the straight side. The burnish height on the radius side increases by 0.43 mm with the increasing punch speed from 10 to 70 mm/s. However, the increased punch velocity did not always increase the burr height. The work hardening that occurs on the straight side is smaller by about 15% than the radius side.
E. Firmansyah; B. Arifvianto; M.A. Muflikhun; M. Mahardika
AIP Conference Proceedings
Year: 2023 | Conference Paper | Volume: 2675 | Publisher: AIP Publishing
A.R. Safaruddin; U.A. Salim; S. Suyitno; M. Mahardika; B. Arifvianto
Solid State Phenomena
Year: 2023 | Journal Article | Volume: 354 | Publisher: Trans Tech Publications, Ltd.
Abstract: Electropolishing has been widely used for surface finishing of metallic products in the industry, owing to its excellent capability of producing metallic components with a homogeneously smooth surfaces. However, this treatment is often constrained by the long duration required for the processing. Therefore, an improvement in this process is needed. The aim of this research is to introduce the use of electropolishing with circulated electrolytes for improving the surface finish of brass. In this work, electropolishing was carried out by using circulated H2SO4 electrolyte for 10 to 30 min in a customized electropolishing chamber. The effect of this treatment on surface morphology, surface roughness, and thickness reduction of the brass specimen was determined. The results showed a better capability of electropolishing with circulated electrolyte in decreasing the brass roughness, i.e., by 84%, than that without electrolyte circulation which only reached 45% during 30 min of the treatment.
G.S. Prihandana; T. Sriani; M.F. Jamaludin; F. Yusof; B. Arifvianto; M. Mahardika
Metals
Year: 2023 | Journal Article | Volume: 13, Issue: 2 | Publisher: MDPI AG
Abstract: Material removal rate in electropolishing is often overlooked because this process generally addressed for surface finish; however, it is paramount on metallic sheet machining possessed with intricate geometry. Electropolishing removes metallic material from the surface of a workpiece based on anodic dissolution process. The material removal rate depends on the current density, electrolyte, the strength of the magnetic field, polishing time and temperature. In this study, three factors of applied voltage, electrolyte composition and magnetic field were evaluated using Taguchi approach to improve the material removal rate in the electropolishing of a pure titanium (99.5%) workpiece. The experiments were undertaken as per Taguchi L9 (33) orthogonal array, and further analyzed using Pareto ANOVA to determine the most significant parameter. It was found that the optimum parametric combination to maximize the material removal rate were, applied voltage of 15 V, ethanol concentration of 20 vol.% and magnetic field of 0.51 T. The experimental results show that the responses in electropolishing process can be improved through this approach.
Sylviani; Selo; A.E. Permanasari
2023 1st International Conference on Advanced Engineering and Technologies (ICONNIC)
Year: 2023 | Conference Paper | Publisher: IEEE
Alfian; A.E. Permanasari; S. Fauziati
2023 3rd International Conference on Electronic and Electrical Engineering and Intelligent System (ICE3IS)
Year: 2023 | Conference Paper | Publisher: IEEE
Y. Swandari; R. Ferdiana; A.E. Permanasari
2023 10th International Conference on Electrical Engineering, Computer Science and Informatics (EECSI)
Year: 2023 | Conference Paper | Publisher: IEEE
M. Wahyudi; Tumiran; N.A. Setiawan
2023 International Conference on Advanced Mechatronics, Intelligent Manufacture and Industrial Automation (ICAMIMIA)
Year: 2023 | Conference Paper | Publisher: IEEE
M. Wahyudi; Tumiran; N.A. Setiawan
2023 4th International Conference on High Voltage Engineering and Power Systems (ICHVEPS)
Year: 2023 | Conference Paper | Publisher: IEEE
M.Y. Raya; Tumiran; N.A. Setiawan
2023 International Conference on Advanced Mechatronics, Intelligent Manufacture and Industrial Automation (ICAMIMIA)
Year: 2023 | Conference Paper | Publisher: IEEE
H.A. Nugroho; R. Nurfauzi
JOIV : International Journal on Informatics Visualization
Year: 2023 | Journal Article | Volume: 7, Issue: 4 | Publisher: Society of Visual Informatics
Abstract: The high mortality rate of malaria makes it a severe disease that spreads throughout all-region by infected female Anopheles mosquitoes, especially in tropical countries. Accurate early malaria detection is one of the ways to reduce the mortality rate. Microscopy-based malaria examinations are still considered the gold standard. Due to numerous large malaria patients with limited parasitologists, an automated detection system is needed as a second opinion to assist parasitologists. This study proposed an optimization method for finding an optimal global threshold value for pre-processing parasite detection. There were three stages of the proposed method. The first is to pre-process digital microscopic images using color channel selection, contrast stretching, and morphological operation. The second is to find the global threshold value using multiple modified Otsu’s. The third is to determine the optimum global threshold value. In the last stage, predicted threshold values are generated using a pattern recognition approach to determine the optimum global threshold value. The proposed method evaluated 468 microscopic images captured from hundreds of thin smear blood slides. The slides are provided by the Department of Parasitology-UGM and the Eijkman Institute for Molecular Biology. The set image contains 691 malaria parasites in all types and life stages of malaria parasites. The proposed method obtained a sensitivity of 99.6 % and the smallest FPs number compared to without the optimization. It indicates that the proposed method has the potential to be implemented in the initial stages of the malaria detection system.
H.A. Nugroho; R. Nurfauzi
FACETS
Year: 2023 | Journal Article | Volume: 8 | Publisher: Canadian Science Publishing
Abstract: Malaria is a life-threatening parasitic disease transmitted to humans by infected female Anopheles mosquitoes. Early and accurate diagnosis is crucial to reduce the high mortality rate of the disease, especially in eastern Indonesia, where limited health facilities and resources contribute to the effortless spread of the disease. In rural areas, the lack of trained parasitologists presents a significant challenge. To address this issue, a computer-aided detection (CAD) system for malaria is needed to support parasitologists in evaluating hundreds of blood smear slides every month. This study proposes a hybrid automated malaria parasite detection and segmentation method using image processing and deep learning techniques. First, an optimized double-Otsu method is proposed to generate malaria parasite patch candidates. Then, deep learning approaches are applied to recognize and segment the parasites. The proposed method is evaluated on the PlasmoID dataset, which consists of 468 malaria-infected microscopic images containing 691 malaria parasites from Indonesia. The results demonstrate that our proposed approach achieved an F1-score of 0.91 in parasite detection. Additionally, it achieved better performance in terms of sensitivity, specificity, and F1-score for parasite segmentation compared to original semantic segmentation methods. These findings highlight the potential of this study to be implemented in CAD malaria detection, which could significantly improve malaria diagnosis in resource-limited areas.
E.S. Nugroho; I. Ardiyanto; H.A. Nugroho
International Journal of Advances in Intelligent Informatics
Year: 2023 | Journal Article | Volume: 9, Issue: 3 | Publisher: Universitas Ahmad Dahlan
Abstract: The occurrence of pigmented skin lesions (PSL), including melanoma, are rising, and early detection is crucial for reducing mortality. To assist Pigmented skin lesions, including melanoma, are rising, and early detection is crucial in reducing mortality. To aid dermatologists in early detection, computational techniques have been developed. This research conducted a systematic literature review (SLR) to identify research goals, datasets, methodologies, and performance evaluation methods used in categorizing dermoscopic lesions. This review focuses on using convolutional neural networks (CNNs) in analyzing PSL. Based on specific inclusion and exclusion criteria, the review included 54 primary studies published on Scopus and PubMed between 2018 and 2022. The results showed that ResNet and self-developed CNN were used in 22% of the studies, followed by Ensemble at 20% and DenseNet at 9%. Public datasets such as ISIC 2019 were predominantly used, and 85% of the classifiers used were softmax. The findings suggest that the input, architecture, and output/feature modifications can enhance the model's performance, although improving sensitivity in multiclass classification remains a challenge. While there is no specific model approach to solve the problem in this area, we recommend simultaneously modifying the three clusters to improve the model's performance.
E.S. Nugroho; I. Ardiyanto; H.A. Nugroho
Skin Research and Technology
Year: 2023 | Journal Article | Volume: 29, Issue: 11 | Publisher: Wiley
Abstract: Abstract
Background
Pigmented skin lesions (PSLs) pose medical and esthetic challenges for those affected. PSLs can cause skin cancers, particularly melanoma, which can be life‐threatening. Detecting and treating melanoma early can reduce mortality rates. Dermoscopic imaging offers a noninvasive and cost‐effective technique for examining PSLs. However, the lack of standardized colors, image capture settings, and artifacts makes accurate analysis challenging. Computer‐aided diagnosis (CAD) using deep learning models, such as convolutional neural networks (CNNs), has shown promise by automatically extracting features from medical images. Nevertheless, enhancing the CNN models' performance remains challenging, notably concerning sensitivity.
Materials and methods
In this study, we aim to enhance the classification performance of selected pretrained CNNs. We use the 2019 ISIC dataset, which presents eight disease classes. To achieve this goal, two methods are applied: resolution of the dataset imbalance challenge through augmentation and optimization of the training hyperparameters via Bayesian tuning.
Results
The performance improvement was observed for all tested pretrained CNNs. The Inception‐V3 model achieved the best performance compared to similar results, with an accuracy of 96.40% and an AUC of 0.98.
Conclusion
According to the study, classification performance was significantly enhanced by augmentation and Bayesian hyperparameter tuning.
E.S. Nugroho; I. Ardiyanto; H.A. Nugroho
2023 3rd International Conference on Electronic and Electrical Engineering and Intelligent System (ICE3IS)
Year: 2023 | Conference Paper | Publisher: IEEE
D. Wahyudi; I. Soesanti; H.A. Nugroho
2023 6th International Conference on Information and Communications Technology (ICOIACT)
Year: 2023 | Conference Paper | Publisher: IEEE
E. Irijanti; H.A. Nugroho; I. Ardiyanto
2023 International Workshop on Artificial Intelligence and Image Processing (IWAIIP)
Year: 2023 | Conference Paper | Publisher: IEEE
D.R. Sawitri; P. Mulyono; R. Rochmadi; A. Budiman
Bulletin of Chemical Reaction Engineering & Catalysis
Year: 2023 | Journal Article | Volume: 18, Issue: 3 | Publisher: BCREC Publishing Group
Abstract: Epoxidized oleic acid can be transformed into vegetable oil-based polyesters through a self-polymerization reaction. This study aims to develop the kinetic model for the polymerization reaction between epoxide and carboxyl groups and the product characterization regarding its functional groups, molecular weight, and thermal stability. The polymerization reaction was carried out at the temperature of 120–180 °C for 2–6 h with the highest conversion of oxirane number up to 97%. Kinetic study showed one-step reaction model between oxirane and carboxylic group gives the activation energy value of 34.71 kJ/mol. Furthermore, the two simultaneous reaction model with further reaction between oxirane group and hydroxyl group also taken into account. The later provides a better agreement between the experimental data and the calculated conversion value. The activation energy values in the first and second steps are 38.61 and 26.00 kJ/mol, respectively. The product characterization showed that adding adipic acid did not significantly affect the polymer's molecular weight and thermal stability. The polydisperse characteristics of the poly(oleic acid) produced in this study enable poly(oleic acid) to be used as a lubricant, a polymer additive, or a precursor to produce polymers with higher molecular weights by taking advantage of the accessibility of OH groups. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
R.A. Amiliana; P. Mulyono; H.T.B.M. Petrus
Materials Science Forum
Year: 2023 | Journal Article | Volume: 1093 | Publisher: Trans Tech Publications, Ltd.
Abstract: Rare Earth Elements (REE) concentrate from the processing of xenotime minerals still contains a mixture of REE and its impurities, so it requires a further separation process to purify the content of each element. The first step to separating each element of REE is to dissolve the REE concentrate in strong acid as a feed for the liquid-liquid extraction or ion exchange column process. The REE concentrate was dissolved in 3 variations of strong acids, namely hydrochloric acid, nitric acid, and sulfuric acid. XRF and FTIR analyses were done before and after the dissolution process. The results showed that sulfuric acid is the best dissolution reagent for the total rare earth elements (71.75%) but is less selective for separating light REE, heavy REE, and their impurities. Better selectivity for separating light REE and heavy REE is shown by dissolution with nitric acid with dissolution levels of 37.32% and 81.91%, respectively. Meanwhile, hydrochloric acid showed the lowest dissolution results for the total element of REE (63.14%) but had the best selectivity to prevent the dissolving of radioactive elements. The results of the FTIR analysis showed that REE-chloride, REE-nitrate, and REE-sulfate bonds had been formed in each dissolving filtrate.
R. Wicaksono; P.N. Darma; K. Sakai; D. Kawashima; M. Takei
Sensors and Actuators B: Chemical
Year: 2022 | Journal Article | Volume: 366 | Publisher: Elsevier BV
R. Wicaksono; P.N. Darma; K. Sakai; D. Kawashima; M. Takei
SSRN Electronic Journal
Year: 2022 | Journal Article | Publisher: Elsevier BV
R. Wicaksono; P.N. Darma; A. Inoue; H. Tsuji; M. Takei
Measurement Science and Technology
Year: 2022 | Journal Article | Volume: 33, Issue: 9 | Publisher: IOP Publishing
Abstract: Abstract
A low-power and handy gastric data acquisition (
g
-DAQ) system has been proposed to identify the gastric processes in the epigastric region with sectorial electrical impedance tomography (
s
-EIT) and K-means sectorial clustering algorithm. The
g
-DAQ with a wearable abdominal sensor investigates gastric retention levels in the epigastric region during the emptying process. A C-runtime engine with Secure Shell protocol optimized an ARM microprocessor and field programmable gate array-based system with bidirectional channels to perform real-time data acquisition. The
s
-EIT algorithm projects the gastric conductivity distribution in the epigastric region into a cross-sectional image. K-means clustering method quantitatively identifies the gastric content images on the epigastric region to monitor the different clustered conductivity
α
k
. The phantom experiments evaluated the
s
-EIT using liver-shaped, bone-shaped, and gastric-shaped phantoms in an abdominal-shaped vessel to distinguish gastric phantom conductivity. In human experiments, the proposed method was applied to measure 15 samples of the emptying process to evaluate the retention level of liquid gastric content. As a result, the proposed
g
-DAQ successfully performed a rapid acquisition at least 50 times faster than the conventional method in terms of the data acquisition rate. The developed
g
-DAQ with 110 mm × 66 mm × 51 mm of dimensions and 0.16 kg of weight took 0.32 sec to measure 208 points per frame and consumed 3.67 Watt of average power operation. By drinking 500 ml of rehydration water with 0.69 S m
−1
of conductivity, In subjects 1–4 and phantoms, the maximum
R
(
t
) was identified on
t
1
as the gastric volume is fully bloated. During 30 min, the emptying liquid content was well-indicated because the minimum
R
(
t
) was identified on
t
15
as an empty state. The mean of the measurement results is −0.0387 with the linear equation
R
(
t
) = −0.0387
t
+ 0.8105. In conclusion, the body mass index did not significantly affect the trendline.
S. Murnani; N.A. Setiawan; S. Wibirama
Communications in Science and Technology
Year: 2022 | Journal Article | Volume: 7, Issue: 1 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
Abstract: Human gaze is a promising input modality for being able to be used as natural user interface in touchless technology during Covid-19 pandemic. Spontaneous gaze interaction is required to allow participants to directly interact with an application without any prior eye tracking calibration. Smooth pursuit eye movement is commonly used in this kind of spontaneous gaze-based interaction. Many studies have been focused on various object selection techniques in smooth pursuit-based gaze interaction; however, challenges in spatial accuracy and implementation complexity have not been resolved yet. To address these problems, we then proposed an approach using difference patterns between gaze and dynamic objects' trajectories for object selection named Difference Gaze Pattern method (DGP). Based on the experimental results, our proposed method yielded the best object selection accuracy of and success time of ms. The experimental results also showed the robustness of object selection using difference patterns to spatial accuracy and it was relatively simpler to be implemented. The results also suggested that our proposed method can contribute to spontaneous gaze interaction.
Dwi Fithriyaningrum; S.S. Kusumawardani; S. Wibirama
IJID (International Journal on Informatics for Development)
Year: 2022 | Journal Article | Volume: 11, Issue: 1 | Publisher: Al-Jamiah Research Centre
Abstract: In the digital era, Learning Management System is widely used to spread information in higher education, particularly at the university level. There are, however, issues with the Learning Management System's accessibility for users with disabilities. This research aims to investigate the accessibility issues of learning management websites of 30 universities in Indonesia. The top 30 universities in Indonesia according to Webometrics 2022 are the basis for this study. Accessibility issues will be identified and examined using the Wave evaluation tool which is in accordance with the Web Content Accessibility Guidelines 2.1 used by ISO 40500. Web Content Accessibility Guideline 2.1 has principles that any web should follow: Perceivable, Operable, Understandable, and Robust. Based on the research findings, The low contrast ratio between text and background, the absence of text explanations in the images, the lack of descriptive text on the links, the absence of text labels on the form, and the absence of text description on the button were the most frequently encountered accessibility issues.
A.D. Ramadhan; A.E. Permanasari; S. Wibirama
2022 2nd International Conference on Intelligent Cybernetics Technology & Applications (ICICyTA)
Year: 2022 | Conference Paper | Publisher: IEEE
N. Nurwidiana; B.M. Sopha; A. Widyaparaga
Sustainability
Year: 2022 | Journal Article | Volume: 14, Issue: 9 | Publisher: MDPI AG
Abstract: Energy transitions as socio-technical processes involves interactions among different actors such as households, firms, and government, thus requiring an integrated approach to explore the transition’s dynamics. The present study aims to simulate the socio-technical transitions of photovoltaics (PV) in Indonesia using an empirically based hybrid simulation-optimization model. The model involves households’ decision-making, PV supply chain, and government interventions. The hybrid simulation-optimization model consists of integer linear programming to optimize PV’s supply chain configuration which was embedded within agent-based modeling and simulation (ABM). The empirical data involving 413 households from 34 provinces in Indonesia was acquired from a survey that was specifically designed based on the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2) to specify and parameterize the model. Export tariff regulation, incentives for PV investment, environmental campaigns, and the combinations of those interventions were evaluated. The findings demonstrate that all of the interventions increase the intention toward PV, but the intention is not necessarily translated into adoption due to either financial or facility constraints. The findings highlight the necessity to include both demand and supply aspects endogenously in the transition model. The export tariffs combined with the incentives, followed by the export tariffs combined with the campaigns, is found to be preferable due to low supply chain unit cost and high reduction of greenhouse gas. Managerial implications and future research are discussed.
H. Nugraha; I. Kusumaningtyas; I.M. Miasa
Journal of Mechanical Design and Testing
Year: 2022 | Journal Article | Volume: 4, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Bejana tekan adalah wadah tertutup yang dirancang untuk menampung fluida yang mempunyai tekanan berbeda dengan tekanan lingkungan. Tekanan operasi bejana tekan dapat berupa tekanan internal, tekanan eksternal ataupun kombinasi antara keduanya. Perancangan bejana tekan mengacu ke ASME VIII divisi 1 menggunakan tekanan operasi internal dalam menentukan tebal shell bejana tekan, sedangkan beban tekanan eksternal dikompensasi dengan penambahan stiffener ring. Analisa tebal shell dengan tekanan eksternal perlu dilakukan untuk mengetahui tebal bejana tekan yang sesuai untuk menahan beban tekanan operasi eksternal. Pada penelitian ini dilakukan simulasi finite elemet menggunakan software Abaqus untuk bejana tekan aplikasi bawah laut pada beban tekanan eksternal 2 MPa. Simulasi dilakukan dengan beberapa variasi ketebalan shell baik tanpa menggunakan stiffener ring dan dengan menggunakan beberapa variasi geometri stiffener ring. Variasi tebal shell pada penelitian ini adalah 2 mm, 3 mm dan 4 mm. Selanjutnya simulasi dilakukan dengan penambahan tiga bentuk stiffener ring yang berbeda. Simulasi dengan tiga tipe stiffener ring dilakukan untuk setiap variasi ketebalan shell secara bergantian. Dari hasil simulasi menggunakan variasi tebal tersebut didapatkan pendekatan shell 2,5 mm tanpa menggunakan stiffener ring mampu menahan beban tekanan eksternal 2 MPa dengan eigenvalue 1,179 dan tegangan von Mises yang terjadi adalah 144,5 yang mana masih di bawah yield stress dari material bejana tekan. Dari hasil simulasi, stiffener ring tipe dua dengan rasio contact 0,022 menunjukan paling optimal menambah kekuatan bejana tekan untuk mencegah buckling ditunjukan dengan eigenvalue yang lebih besar dibandingkan hasil simulasi dari variasi lainya.
Suyitno; E. Pujiyulianto; B. Arifvianto; M. Mahardika; U.A. Salim
Materials Science and Technology
Year: 2022 | Journal Article | Volume: 38, Issue: 5 | Publisher: SAGE Publications
Abstract: The research aims to evaluate the quantitative hot cracking criteria. The quantitative criteria, i.e. the SKK (Suyitno–Kool–Katgerman) and the modified SKK criteria were implemented with various parameters such as the cooling rate, strain rate, grain diameter, packing parameter, Mg content in Al9ZnxMg2Cu, and Cu content in Al9Zn2MgxCu. The validation of the result is also conducted by comparing the implementation result with the experimental data. The results show that the hot cracking initiation based on the SKK criterion occurs at lower stress and higher solid fraction than that based on the modified SKK criterion. This means that hot cracking initiation based on the SKK criteria occurs earlier than that based on the modified SKK criteria. Based on the modified SKK criterion, the critical stress initially decreases sharply and then increases gradually with solid fraction, whereas the critical stress remains decreased based on the SKK criterion.
A.W. Ardyanto; B. Arifvianto; M. Mahardika; M.A. Muflikhun
2022 5th International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2022 | Conference Paper | Publisher: IEEE
F.A. Wibisono; M. Mahardika; B. Arifvianto; A.T. Fismatika; M.A. Muflikhun
Journal of Mechanical Science and Technology
Year: 2022 | Journal Article | Volume: 36, Issue: 7 | Publisher: Springer Science and Business Media LLC
B. Arifvianto; B.E. Satiti; U.A. Salim; Suyitno; A. Nuryanti; M. Mahardika
Progress in Additive Manufacturing
Year: 2022 | Journal Article | Volume: 7, Issue: 6 | Publisher: Springer Science and Business Media LLC
A. Sandi; M. Mahardika; S.I. Cahyono; U.A. Salim; J. Pratama; B. Arifvianto
Conference SENATIK STT Adisutjipto Yogyakarta
Year: 2022 | Journal Article | Volume: 7 | Publisher: Institut Teknologi Dirgantara Adisutjipto (ITDA)
Ardiansyah; R. Ferdiana; A.E. Permanasari
2022 9th International Conference on Electrical Engineering, Computer Science and Informatics (EECSI)
Year: 2022 | Conference Paper | Publisher: IEEE
Ardiansyah; R. Ferdiana; A.E. Permanasari
2022 5th International Conference on Information and Communications Technology (ICOIACT)
Year: 2022 | Conference Paper | Publisher: IEEE
A. Ardiansyah; R. Ferdiana; A.E. Permanasari
Applied Sciences
Year: 2022 | Journal Article | Volume: 12, Issue: 3 | Publisher: MDPI AG
Abstract: Particle Swarm Optimization is a metaheuristic optimization algorithm widely used across a broad range of applications. The algorithm has certain primary advantages such as its ease of implementation, high convergence accuracy, and fast convergence speed. Nevertheless, since its origin in 1995, Particle swarm optimization still suffers from two primary shortcomings, i.e., premature convergence and easy trapping in local optima. Therefore, this study proposes modified chaotic particle swarm optimization with uniform particle initialization to enhance the comprehensive performance of standard particle swarm optimization by introducing three additional schemes. Firstly, the initialized swarm is generated through a uniform approach. Secondly, replacing the linear inertia weight by introducing the nonlinear chaotic inertia weight map. Thirdly, by applying a personal learning strategy to enhance the global and local search to avoid trap in local optima. The proposed algorithm is examined and compared with standard particle swarm optimization, two recent particle swarm optimization variants, and a nature-inspired algorithm using three software effort estimation methods as benchmark functions: Use case points, COCOMO, and Agile. Detailed investigations prove that the proposed schemes work well to develop the proposed algorithm in an exploitative manner, which is created by a uniform particle initialization and avoids being trapped on the local optimum solution in an explorative manner and is generated by a personal learning strategy and chaotic-based inertia weight.
Z. Athiyah; A.E. Permanasari; S. Wibirama
2022 4th International Conference on Biomedical Engineering (IBIOMED)
Year: 2022 | Conference Paper | Publisher: IEEE
A. Ardiansyah; R. Ferdiana; A.E. Permanasari
International Journal of Advances in Intelligent Informatics
Year: 2022 | Journal Article | Volume: 8, Issue: 2 | Publisher: Universitas Ahmad Dahlan
Abstract: Among algorithmic-based frameworks for software development effort estimation, Use Case Points I s one of the most used. Use Case Points is a well-known estimation framework designed mainly for object-oriented projects. Use Case Points uses the use case complexity weight as its essential parameter. The parameter is calculated with the number of actors and transactions of the use case. Nevertheless, use case complexity weight is discontinuous, which can sometimes result in inaccurate measurements and abrupt classification of the use case. The objective of this work is to investigate the potential of integrating particle swarm optimization (PSO) with the Use Case Points framework. The optimizer algorithm is utilized to optimize the modified use case complexity weight parameter. We designed and conducted an experiment based on real-life data set from three software houses. The proposed model’s accuracy and performance evaluation metric is compared with other published results, which are standardized accuracy, effect size, mean balanced residual error, mean inverted balanced residual error, and mean absolute error. Moreover, the existing models as the benchmark are polynomial regression, multiple linear regression, weighted case-based reasoning with (PSO), fuzzy use case points, and standard Use Case Points. Experimental results show that the proposed model generates the best value of standardized accuracy of 99.27% and an effect size of 1.15 over the benchmark models. The results of our study are promising for researchers and practitioners because the proposed model is actually estimating, not guessing, and generating meaningful estimation with statistically and practically significant.
Rinaldi; R. Ferdiana; N.A. Setiawan
2022 IEEE International Conference of Computer Science and Information Technology (ICOSNIKOM)
Year: 2022 | Conference Paper | Publisher: IEEE
N. Wulandari; I. Ardiyanto; H. Adi Nugroho
Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi)
Year: 2022 | Journal Article | Volume: 6, Issue: 2 | Publisher: Ikatan Ahli Informatika Indonesia (IAII)
Abstract: In recent year, marine ecosystems and fisheries becomes potential resources, therefore, monitoring of these objects will be important to ensure their existence. One of computer vision techniques, it is object detection, utilized to recognize and localize objects in underwater scenery. Many studies have been conducted to investigate various deep learning methods implemented in underwater object detection; however, only a few investigations have been performed to compare mainstream object detection algorithms in these circumstances. This article examines various state-of-the-art deep learning methods applied to underwater object detection, including Faster-RCNN, SSD, RetinaNet, YOLOv3, and YOLOv4. We trained five models on RUIE dataset, then the average detection time used to compare how fast a model can detect object within an image; and mAP also applied to measured detection accuracy. All trained models have costs and benefits; SSD was fast but had poor performance; RetinaNet had consistent performance across different thresholds but the detection speed was slow; YOLOv3 was the fastest and had sufficient performance comparable with RetinaNet; YOLOv4 was good at first but performance dropped as threshold enlargement; also, YOLOv4 needed extra time to detect objects compared to YOLOv3. There are no models that are fully suited for underwater object detection; nonetheless, when the mAP and average detection time of the five models were compared, we determined that YOLOv3 is the best acceptable model among the evaluated underwater object detection models.
E.M. Nainggolan; P. Mulyono; A. Prasetya
Key Engineering Materials
Year: 2022 | Journal Article | Volume: 920 | Publisher: Trans Tech Publications, Ltd.
Abstract: This study reports the removal of cadmium ions in aqueous solution as the artificial waste using natural zeolite as the adsorbent. Natural zeolite was characterized by using XRD (X – Ray Diffraction) and XRF (X-Ray fluorescence) analysis. The XRD results show that the natural zeolite derived from Klaten, Jawa Tengah, is mordenite type and the XRF results show that Si/Al ratio is 5.688 % (medium). A batch adsorption method is carried out at room temperature varied adsorbent dose. Equilibrium of adsorption data were analyzed using the Langmuir and Freundlich isotherm model. The values of the parameters constants for the Langmuir equation were qmax = -2.301 mg/g and KL = -1.00067 while the Freundlich equation were Kf = 3.999 and n = 0.845. It was found that the Freundlich adsorption model is better than the Langmuir isotherm model with high coefficient of determination. In this study, the removal efficiency for Cd2+ was 99.4 % for adsorbent dose of 70 g/L. It can be concluded that the natural zeolite of mordenite type is a very potential adsorbent for removal Cd2+. Therefore, the utilization of zeolite should to be encouraged in a larger scale especially in the environmental application.
P. Mulyono; A.S. Yuzki; M.D. Sari; N.R.E. Putri
ASEAN Journal of Chemical Engineering
Year: 2022 | Journal Article | Volume: 22, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: This research aims to investigate the best operating condition for the extraction process of flavonoids from Merremia mammosa root by determining the mass transfer coefficient (Ke). The root was prepared by drying, crushing, and sieving into a homogeneous size and then extracted in a fixed-bed column using 70 wt% of ethanol as a solvent for 2 hours. The obtained samples were then analyzed every 30 min using high-performance liquid chromatography. The parameters investigated in this research were particle size of 1.275, 1.85, and 4.01 mm and solvent flow rate of 3, 6, and 9 mL/s. Based on the experimental data, the value of Ke was calculated using the Hooke-Jeeves numerical method of optimization. The results showed that the decrease in particle size and the increase in solvent flow rate could increase the Ke values, leading to the high concentration of flavonoids extracted using the solvent. The Ke values obtained in this research ranged from 0.3145 m/s to 0.7880 m/s. The empirical equation that shows the correlation between Ke and the parameters can be expressed as Sh = 1.10 × 1014 Re0.0564 (1 − ε)0.8718 with a relative error of 6.13% compared with the experimental data (Sh is the Sherwood number, Re is the Reynolds number, and ε is the porosity of the fixed-bed column).
H. Nurlatifa; R. Hartanto; S. Wibirama
2021 5th International Conference on Informatics and Computational Sciences (ICICoS)
Year: 2021 | Conference Paper | Publisher: IEEE
H.Z. Wijasena; R. Ferdiana; S. Wibirama
2021 International Conference on Artificial Intelligence and Mechatronics Systems (AIMS)
Year: 2021 | Conference Paper | Publisher: IEEE
V.P. Waroy; S. Wibirama; I. Ardiyanto
2021 International Conference on Computer System, Information Technology, and Electrical Engineering (COSITE)
Year: 2021 | Conference Paper | Publisher: IEEE
L. Ardi; N.A. Setiawan; S. Wibirama
IJITEE (International Journal of Information Technology and Electrical Engineering)
Year: 2021 | Journal Article | Volume: 5, Issue: 4 | Publisher: Universitas Gadjah Mada
Abstract: Disability is a physical or mental impairment. People with disability have more barriers to do certain activity than those without disability. Moreover, several conditions make them having difficulty to communicate with other people. Currently, researchers have helped people with disabilities by developing brain-computer interface (BCI) technology, which uses artifact on electroencephalograph (EEG) as a communication tool using blinks. Research on eye blinks has only focused on the threshold and peak amplitude, while the difference in how many blinks can be detected using peak amplitude has not been the focus yet. This study used primary data taken using a Muse headband on 15 subjects. This data was used as a dataset classified using bagging (random forest) and boosting (XGBoost) methods with python; 80% of the data was allocated for learning and 20% was for testing. The classified data was divided into ten times of testing, which were then averaged. The number of eye blinks’ classification results showed that the accuracy value using random forest was 77.55%, and the accuracy result with the XGBoost method was 90.39%. The result suggests that the experimental model is successful and can be used as a reference for making applications that help people to communicate by differentiating the number of eye blinks. This research focused on developing the number of eye blinks. However, in this study, only three blinking were used so that further research could increase these number.
P.P. Jati; A. Widyaparaga
Journal of Mechanical Design and Testing
Year: 2021 | Journal Article | Volume: 3, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: Dalam praktik di industri hulu minyak dan gas (migas), permasalahan aliran dua fasa merupakan bagian penting di semua siklus kegiatan dari desain hingga operasi. Fluida dari sumur produksi menghasilkan campuran minyak, air, gas, dan juga pasir yang sangat mungkin membentuk berbagai macam pola aliran. Sehingga dapat disimpulkan bahwa pemahaman akan pola aliran dan sifat fluida sangat penting untuk analisis, prediksi, dan mitigasi perubahan kondisi reservoir untuk menjaga stabilitas proses produksi. Untuk meningkatkan pemahaman pola aliran salah satunya pola stratified dilakukan penelitian mencari konfigurasi simulasi 2 dimensi campuran minyak dan air menggunakan Computational Fluid Dynamics (CFD). Penelitan yang dilakukan menghasilkan analisis sifat dinamika kecepatan gelombangmelalui perpaduan permodelan simulasi CFD serta image processing-cross correlation serta perbandingan hasil dengan eksperimen.Model yang dipilih untuk memprediksi antarmuka minyak-air di dalam pipa horizontal berdiameter 24 mm dan panjang 1200 mm adalah multiphase Eulerian Multi-Fluid VOF yang dipasangkan dengan model turbulensi shear stress transport (SST) k-ω yang dilengkapi dengan turbulence damping. Analisis dilakukan pada titik dari inlet dengan jarak 10 x diameter (10 D) dan 40 x diameter (40 D) dengan 4 variasi kecepatan. Hasil menunjukkan peningkatan rerata ketebalan film dan kecepatan gelombang seiring denganmeningkatnya kecepatan superfisial air dengan kecepatan superfisial minyak tetap. Dapat disimpulkan model multiphase Eulerian Multi-Fluid VOF yang dipasangkan dengan model turbulensi shear stress transport (SST) k-ω dan turbulence damping pada Ansys Fluent 19 mampu mensimulasikan aliran minyak dan air pada stratified regime denganbentuk gelombang serta dinamika kecepatan gelombang yang saling bersesuaian dengan hasil eksperimen.
M.R. Pradecta; A.I. Majid; A. Widyaparaga
Journal of Physics: Conference Series
Year: 2021 | Journal Article | Volume: 1772 | Publisher: IOP Publishing
Sugiyanto; S. Kamal; J. Waluyo; A. Widyaparaga
Journal of Physics: Conference Series
Year: 2021 | Journal Article | Volume: 1772, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
Standing wave thermoacoustic engine (SWTE) is a device for converting heat to propagate acoustic wave within straight and tubular of the resonator. The advantages of this engine include being able to use the waste heat as a source of heating, no moving parts and environmentally friendly. The utilization of this acoustic wave is to rotate air turbine because its movement that goes back and forth. The type of air turbine that appropriates to this character one of these is Wells bi-directional turbine, which is always rotated in the same direction regardless of the moving air direction. This study aims to investigate the performance of Wells turbine when paired with SWTE in the variation on geometry shape of blade and hub to tip ratio. The Wells turbine was embedded inside resonator of this engine has a diameter of 50 mm in the manner of the hub to tip ratio 0.6. The geometry shape of blade varied with airfoil type of NACA 0015, NACA 0018 and NACA 0024. SWTE was generating 4,67 kPa acoustic pressure and 138 Hz frequency within 52 mm inside diameter, 390 mm length of the resonator. The result was the Wells turbine NACA 0018 has rotational motion 2449 rpm, higher than the others types. Wells turbine NACA 0018 then tested with variations of the hub to tip ratio. Results showed that are generated rotational motion at 2614 rpm, 2449 rpm and 1555 rpm for 0.5, 0.6, 0.7 hub to tip ratio, respectively.. It can be concluded that the Well turbine NACA 0018 with hub to tip ratio 0,5 has best performance compare to the others.
Deendarlianto; M.R. Pradecta; T. Prakoso; Indarto; W.H. Mitrakusuma; A. Widyaparaga
Heat and Mass Transfer
Year: 2021 | Journal Article | Volume: 57, Issue: 7 | Publisher: Springer Science and Business Media LLC
K.A. Yuana; B. Jalaali; E.P. Budiana; Pranowo; A. Widyaparaga; Indarto; Deendarlianto
European Journal of Mechanics - B/Fluids
Year: 2021 | Journal Article | Volume: 85 | Publisher: Elsevier BV
A. Akhmadiansyah; I.M. Miasa
Journal of Mechanical Design and Testing
Year: 2021 | Journal Article | Volume: 3, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: AbstrakPenambahan lubang perforasi pada tubing liner dengan variasi ukuran diameter dan jumlah lubang menjadikan rasio area perforasi meningkat. Dengan rasio area perforasi meningkat tentunya secara profit dapat menambah hasil produksi, namun juga berpotensi dapat menurunkan kekuatan material karena hilangnya sejumlah massa material. Penelitian ini bertujuan untuk mengetahui pengaruhnya terhadap nilai tegangan (σ) dan konsentrasi (Kt) serta variasi perforasi yang memiliki nilai kekuatan sesuai standar. Penelitian berupa studi eksperimental dan numerik untuk menghasilkan model tubing liner berbahan material dan komponen buatan dalam negeri dengan memanfaatkan raw material hasil sumber daya alam Indonesia. Pengujian eksperimental dengan menggunakan material pipa tahan karat stainless steel 304 melalui metode uji tarik (tensile test) dan uji tekan (compressive test). Pengujian ini untuk mendapatkan nilai tegangan (σ) dan regangan (ε) material uji. Secara paralel, simulasi analisis elemen hingga juga dilakukan guna memperoleh data output yang kemudian divalidasi dengan hasil pengujian. Hasil penelitian menunjukkan material pipa tubing stainless steel 304 pada pengujian memiliki nilai tegangan luluh sebesar 364,3 MPa, tegangan tarik maksimum sebesar 597,45 MPa, dan tegangan tekan maksimum sebesar 701,83 MPa, dengan demikian material tubing telah memenuhi standar AISI 304 ASTM A240. Nilai faktor konsentrasi tegangan (Kt) meningkat dari 1,12 hingga 2,39 dan menyebabkan nilai tegangan (σ) pada material semakin berkurang. Faktor konsentrasi tegangan (Kt) yang terjadi dapat menurunkan kekuatan struktur material. Penambahan lubang perforasi pada eksperimen uji tarik menurunkan nilai tegangan sebesar 4,15% dan pada uji tekan sebesar 30,6%. Kombinasi jumlah dan diameter perforasi yang terbaik pada penelitian adalah pada spesimen berdiameter lubang 10 mm karena memberikan nilai tegangan maksimum diatas nilai standar ASTM A240.
C. Irawan; B. Arifvianto; M. Mahardika
JTT (Jurnal Teknologi Terapan)
Year: 2021 | Journal Article | Volume: 7, Issue: 2 | Publisher: P3M Politeknik Negeri Indramayu
Abstract: Currently, fused deposition modeling (FDM) has become a popular 3D printing technique for the fabrication of polymeric parts. In this technique, a polymer filament is melted and deposited layer-by-layer to form 3-dimensional objects. However, there are still limited number of polymer types that has been successfully used as a raw material for the FDM process. Up to now, there is still no filament made from ultra high molecular weight polyethylene (UHMWPE) available in the market. Therefore, a preliminary study concerning the fabrication of such UHMWPE filament needs to be conducted. In this study, the influence of extrusion temperature used in the fabrication of UHMWPE filament on the physical, chemical, and tensile strength of such filament was studied. The extrusion process was carried out by adding polyethylene glycol (PEG) and paraffin oil (PO) to improve the processability of UHMWPE material and with temperatures of 160 oC, 170 oC, and 180 °C. The result of examination by using electron microscope revealed that extrusion process of this polymer was running stable. The characterization by using differential scanning calorimetry (DSC) indicated a decrease in the degree of filament crystallinity as the extrusion temperature decreased. The characterization by using Fourier-transform infrared spectroscopy (FTIR) indicated no changes in the chemical compositions over the filament products with the increasing extrusion temperature applied. Meanwhile, it is also indicated from this study that the maximum tensile strength decreased as the extrusion temperature got lower. In this case, the highest maximum tensile strength could be achived by the UHMWPE filament extruded with temperature of 180 °C, i.e., with an average tensile strength of 22.52 MPa.
D. Oktavian; B. Arifvianto; M. Mahardika
Jurnal Material Teknologi Proses: Warta Kemajuan Bidang Material Teknik Teknologi Proses
Year: 2021 | Journal Article | Volume: 2, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Dewasa ini teknologi additive manufacturing (AM) mengalami perkembangan yang pesat. Salah satu metode additive manufacturing yang saat ini populer di berbagai belahan dunia adalah metode fused deposition modelling. Prinsip kerja metode ini adalah dengan cara mengekstrusi material filamen polimer yang meleleh dan sudah melewati temperatur rekristalisasinya melalui sebuah nozzle, kemudian produk akan terbentuk secara lapis demi lapis yang dibentuk melalui gerakan relatif dari meja mesin. Dalam pengaplikasiannya, material filamen dapat dibuat dalam bentuk komposit sehingga diperoleh sifat-sifat unik tertentu sehingga dapat digunakan pada bidang-bidang tertentu. Salah satunya adalah pada bidang kesehatan, sebagai pembuatan implan atau jaringan tubuh dengan memiliki kekuatan yang tinggi dan bersifat biodegradable. Pada penelitian ini, dilakukan pembuatan filamen komposit PLA-CNT dengan metode ekstrusi. Proses ekstrusi dilakukan dengan variasi temperatur 143, 145, dan 147ºC dengan memberi tambahan polyethylene glycol (PEG) sebagai plasticizer untuk meningkatkan fleksibilitas dan workability. Hasil pengamatan dengan scanning electron microscope (SEM) mengindikasikan bahwa proses ekstrusi berjalan kurang stabil karena terdapat tekstur permukaan yang bergelombang. Dari pengujian karakterisasi differential scanning calorimetry (DSC), derajat kristalinitas pada variasi ekstrusi filamen PLA-CNT mengalami peningkatan seiring meningkatnya temperatur ekstrusi. Pada pengujian karakterisasi fourier transform infrared spectroscopy (FTIR) terdapat perubahan komposisi kimia pada filamen yang signifikan, yang juga sejalan dengan degradasi sifat mekanis. Variasi filamen dengan temperatur ekstrusi 147ºC memiliki nilai kekerasan paling tinggi yaitu sebesar 40,50 MPa.
B. Arifvianto; Y.B. Wirawan; U.A. Salim; S. Suyitno; M. Mahardika
Rapid Prototyping Journal
Year: 2021 | Journal Article | Volume: 27, Issue: 10 | Publisher: Emerald
Abstract: Purpose
The purpose of this study is to investigate the influences of extruder temperatures and raster orientations on the mechanical properties of polylactic-acid (PLA) material processed by using fused filament fabrication (FFF).
Design/methodology/approach
In this research, the PLA specimens were first printed with nozzle or extruder temperatures of 205°C, 215°C and 225°C and then evaluated in terms of their physical, chemical and mechanical properties. An appropriate extruder temperature was then selected based on this experiment and used for the printing of the other PLA specimens having various raster orientations. A series of tensile tests were carried out again to investigate the influence of raster orientations on the tensile strength, tensile strain and elastic modulus of those FFF-processed PLA materials. In the end, the one-way ANOVA was applied for the statistical analysis and the Mohr’s circle was established to aid in the analysis of the data obtained in this experiment.
Findings
The result of this study shows that the chemistry, porosity, degree of crystallinity and mechanical properties (tensile strength, strain and elastic modulus) of the PLA material printed with a raster angle of 0° were all insensitive to the increasing extruder temperature from 205°C to 225°C. Meanwhile, the mechanical properties of such printed PLA material were obviously influenced by its raster orientation. In this case, a PLA material with a raster orientation parallel to its loading axis, i.e. those with a raster angle of θ = 0°, was found as the strongest material. Meanwhile, the raster configuration-oriented perpendicular to its loading axis or θ = 90° yielded the weakest PLA material. The results of the tensile tests for the PLA material printed with bidirectional raster orientations, i.e. θ = 0°/90° and 45°/−45° demonstrated their strengths with values falling between those of the materials having unidirectional raster θ = 0° and 90°. Furthermore, the result of the analysis by using a well-known Mohr’s circle confirmed the experimental tensile strengths and the failure mechanisms of the PLA material that had been printed with various raster orientations.
Originality/value
This study presented consistent results on the chemistry, physical, degree of crystallinity and mechanical properties of the FFF-processed PLA in responding to the increasing extruder temperature from 205°C to 225°C applied during the printing process. Unlike the results of the previous studies, all these properties were also found to be insensitive to the increase of extruder temperature. Also, the result of this research demonstrates the usability of Mohr’s circle in the analysis of stresses working on an FFF-processed PLA material in responding to the changes in raster orientation printed in this material.
M.I. Zulfa; R. Hartanto; A.E. Permanasari
2021 IEEE International Conference on Communication, Networks and Satellite (COMNETSAT)
Year: 2021 | Conference Paper | Publisher: IEEE
S. Afifi; N.A. Setiawan
Communications in Humanities and Social Sciences
Year: 2021 | Journal Article | Volume: 1, Issue: 2 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
Abstract: This paper aims to explore the notion of communication ethics in the Book of Adabul Mufrad by Imam Al-Bukhari. This study used an interpretive paradigm of qualitative text analysis methods by making Hadith as the text to be analyzed. The units of analysis are the texts of Hadith, which were examined closely for the patterns, models, and communication issues contained in them. The selection criteria for the Hadith selected for analysis included: Ethics regarding the communication process, including an explanation of Ethics in speech, and containing specific prohibitions in the communication process. Based on these criteria, 20 hadiths to be analyzed were selected. The results showed four patterns of ethical communication relationships in 20 hadiths chosen in the book of Adabul Mufrad by Imam Al-Bukhari, namely: (1) Relationships with fellow humans in general, (2) Parent-Child Relations, (3) Relationships with neighbors; and (4) Master-Servant Relationship. Furthermore, communication ethics in all forms of relationships showed five communication ethics patterns: (1) monotheism communication, (2) advice communication, (3) compassion communication, (4) communication without discrimination, and (5) communication without insulting. This paper highlights the ethics of Islamic communication as the ethical basis for the communication process in various human communication contexts. The ethical principles of Islamic communication open the entry of missing behavioral aspects of communication-based on religious values. This paper also provides the necessary theoretical framework for including religiosity and divine guidance in communication ethics.
S. Sari; I. Soesanti; N.A. Setiawan
BIO Web of Conferences
Year: 2021 | Journal Article | Volume: 41 | Publisher: EDP Sciences
Abstract: Lung cancer is a type of cancer that spreads rapidly and is the leading cause of mortality globally. The Computer-Aided Detection (CAD) system for automatic lung cancer detection has a significant influence on human survival. In this article, we report the summary of relevant literature on CAD systems for lung cancer detection. The CAD system includes preprocessing techniques, segmentation, lung nodule detection, and false-positive reduction with feature extraction. In evaluating some of the work on this topic, we used a search of selected literature, the dataset used for method validation, the number of cases, the image size, several techniques in nodule detection, feature extraction, sensitivity, and false-positive rates. The best performance CAD systems of our analysis results show the sensitivity value is high with low false positives and other parameters for lung nodule detection. Furthermore, it also uses a large dataset, so the further systems have improved accuracy and precision in detection. CNN is the best lung nodule detection method and need to develop, it is preferable because this method has witnessed various growth in recent years and has yielded impressive outcomes. We hope this article will help professional researchers and radiologists in developing CAD systems for lung cancer detection.
S. Sari; I. Soesanti; N.A. Setiawan
2021 IEEE 5th International Conference on Information Technology, Information Systems and Electrical Engineering (ICITISEE)
Year: 2021 | Conference Paper | Publisher: IEEE
F. Fauzi; A.E. Permanasari; N. Akhmad Setiawan
2021 3rd International Conference on Electronics Representation and Algorithm (ICERA)
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; R. Nurfauzi
2021 17th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; R. Nurfauzi
2021 IEEE International Biomedical Instrumentation and Technology Conference (IBITeC)
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; R. Nurfauzi
2021 4th International Conference on Information and Communications Technology (ICOIACT)
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; E.L. Frannita
2021 4th International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; E.L. Frannita
2021 International Conference on Computer Science and Engineering (IC2SE)
Year: 2021 | Conference Paper | Publisher: IEEE
H.A. Nugroho; E.L. Frannita
2021 International Conference on Computer System, Information Technology, and Electrical Engineering (COSITE)
Year: 2021 | Conference Paper | Publisher: IEEE
D.K. Nugroho; N.A. Setiawan; H.A. Nugroho
2021 9th International Conference on Information and Communication Technology (ICoICT)
Year: 2021 | Conference Paper | Publisher: IEEE
D.R. Sawitri; P. Mulyono; R. Rochmadi; A. Budiman
Jurnal Teknologi
Year: 2021 | Journal Article | Volume: 83, Issue: 6 | Publisher: Penerbit UTM Press
Abstract: Epoxides from vegetable oils are currently gaining more attention to replace petroleum-based monomers for polymer synthesis. As one of unsaturated fatty acids derived from vegetable oil, Oleic acid can be converted into epoxidized oleic acid by chemical epoxidation. Epoxidized oleic acid is a bifunctional monomer that has the potential to be used as raw material for fatty-acid-based polyester synthesis. This paper proposes the Taguchi-based optimization technique for in-situ epoxidation of oleic acid. The combining factors affecting the maximum yield were also determined to obtain a higher quality of epoxidized oleic acid in a relatively short time. Epoxidized oleic acid was characterized and tested for degradation. The characterization result showed the possibility of the polymerization reaction, and the kinetic study showed that the rate of epoxide degradation at room temperature follows second order with a reaction rate constant of2.7235 gr.mmol-1.day-1.
P. Mulyono; S.S. Utami; B. Prayitno; F.R. Salis; F. Faridah
Journal of Sustainability Perspectives
Year: 2021 | Journal Article | Volume: 1 | Publisher: Institute of Research and Community Services Diponegoro University (LPPM UNDIP)
Abstract: Water management is one of the most challenging aspects of campus management. With a large number on campus population and limited water resources, water management is essential for achieving a resilient and healthy campus. In this paper, we explain two targets in UGM water management: water efficiency and water conservation. Both objectives are significantly related; however, each goal has a different approach to the method for the design approach and strategies in the implementations. Water efficiency is included in building new buildings and retrofitting the existing ones. Meanwhile, water conservation is implemented to calculate potential alternative water resources in UGM, including water treatment, to produce freshwater as an additional water supply. We also explain how water management is implemented in UGM from the highest Directorate to the lowest units. Through our method and best practices in UGM, we hope our paper could be a reference for other universities who want to implement a water management program.
G. Prameswara; I. Trisnawati; P. Mulyono; A. Prasetya; H.T.B.M. Petrus
JOM
Year: 2021 | Journal Article | Volume: 73, Issue: 4 | Publisher: Springer Science and Business Media LLC
Hudalizaman; I. Ardiyanto; S. Wibirama
2020 6th International Conference on Science and Technology (ICST)
Year: 2020 | Conference Paper | Publisher: IEEE
H. Nurlatifa; S. Wibirama; R. Hartanto
2020 6th International Conference on Science and Technology (ICST)
Year: 2020 | Conference Paper | Publisher: IEEE
M. Alfaroby E.; S. Wibirama; I. Ardiyanto
2020 12th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2020 | Conference Paper | Publisher: IEEE
I. Ardiyanto; S. Wibirama; F. Nurwanto
Journal of King Saud University - Computer and Information Sciences
Year: 2020 | Journal Article | Volume: 32, Issue: 7 | Publisher: Springer Science and Business Media LLC
S. Wibirama; S. Murnani; N.A. Setiawan
ACM Symposium on Eye Tracking Research and Applications
Year: 2020 | Conference Paper | Publisher: ACM
W.S. Prakoso; I. Soesanti; S. Wibirama
2020 12th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2020 | Conference Paper | Publisher: IEEE
E. Rekayana; A. Widyaparaga
Journal of Mechanical Design and Testing
Year: 2020 | Journal Article | Volume: 2, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Aliran minyak-air dalam pipa akan membentuk pola aliran beragam tergantung dari kondisi perpipaan dan properti fluida. Salah satu pola aliran yang terbentuk adalah aliran stratified wavy. Fokus penelitian ini adalah melakukan simulasi komputasi dinamika fluida (CFD) untuk menganalisa karakteristik tebal film dan frekuensi gelombang dalam aliran stratified wavy yang tervalidasi dengan hasil penelitian eksperimen. Simulasi menggunakan pipa horizontal dengan diameter 24 mm dan panjang 1200 mm. Simulasi menggunakan Ansys Fluent 19 dengan model multiphase Eulerian multi-fluid VOF dan shear stress transport (SST) k-ω. Pada penelitian ini, simulasi mengaktifkan turbulence damping untuk memprediksi antramuka minyak dan air lebih tajam. Hasil simulasi akan diubah kedalam bentuk video dan kemudian akan dianalisa dengan MATLAB menggunakan metode image processing agar diperoleh nilai tebal film dan frekuensi gelombang. Analisis dilakukan pada delapan kecepatan superfisial minyak maupun air. Pengamatan dilakukan di dua titik yaitu titik 240 mm (10D) dan 960 mm (40D). Hasil simulasi menunjukkan rata-rata tebal film cenderung naik seiring meningkatnya kecepatan superfisial air. Terdapat rata-rata deviasi sebesar 15% dari enam belas data pengamatan tebal film di dua titik pengamatan jika dibandingkan dengan hasil eksperimen. Frekuensi gelombang mengalami kenaikan seiring dengan kenaikan kecepatan superfisial minyak maupun air. Frekuensi gelombang menurun ketika titik pengamatan semakin jauh dari daerah masuk fluida. Karakteristik ini tervalidasi dengan hasil eksperimen sebelumnya.
A.I. Santosa; A. Widyaparaga
Journal of Mechanical Design and Testing
Year: 2020 | Journal Article | Volume: 2, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Penelitian mengenai amplitudo gelombang pada aliran dua fasa minyak-air rezim pola aliran stratified wavy telah dilakukan dalam beberapa penelitian sebelumnya. Namun mengingat banyaknya variasi properties fluida kerja, variasi dimensi dan geometri saluran, serta variasi kondisi parameter operasi maka menurut penulis, penelitian yang sudah ada saat ini masih belum mencukupi untuk memahami bagaimana pengaruh perubahan kecepatan superfacial dan jarak dari inlet sumber aliran terhadap amplitudo gelombang. Penelitian dilakukan untuk menginvestigasi perubahan amplitudo terhadap kenaikan kecepatan superfacial dan terhadap jarak inlet pada aliran dua fasa minyak air dalam rezim pola aliran stratified wavy dalam kondisi sebelum dan saat transisi ke rezim aliran non stratified flow pada fluida kerja. Fluida minyak yang digunakan adalah kerosene dengan masa jenis 781,1 kg / m3, viskositas 1,3 mPa·s dan interfacial tension 0,167 mN/m. Kerosene dan air dialirkan pada pipa horizontal yang terbuat dari bahan akrilik dengan diameter 24 mm. Parameter operasi kecepatan superfacial minyak dijaga konstan sebesar 0,073 m/s. Perbandingan aliran kecepatan superfacial air terhadap kecepatan superfacial minyak pada kondisi entry (input ratio) sebesar 1; 2; 3 dan 4. Proses pengambilan data dilakukan pada titik pengamatan 10D, 40D, 100D dan 220D dari inlet, dimana D adalah diameter dalam pipa. Proses perekaman dilakukan dengan high speed camera frekuensi 600 fps. Data ekseperimen diolah dengan menggunakan metode pengolahan citra untuk mendapatkan ketebalan lapisan air rata-rata dan distribusi probabilitas amplitudo pada setiap titik pengamatan. Kenaikan input ratio akan menyebabkan terjadinya kenaikan ketinggian lapisan air rata-rata sebesar 12 % dengan standard deviasi 5,7 %. Peningkatan input ratio ini juga akan meningkatkan besarnya amplitudo rata-rata pada setiap titik pengamatan dengan peningkatan tertinggi terjadi di titik 10 D dan terendah di titik 220 D. Kenaikan input ratio menyebabkan kenaikan amplitudo antarmuka gelombang dan ketebalan lapisan permukaan air.Munculnya droplet pada gelombang merupakan tanda bahwa gelombang mengamai ketidakstabilan dan masuk ke fasa transisi (onset entrainment).
Sugiyanto; S. Kamal; J. Waluyo; A. Widyaparaga
AIP Conference Proceedings
Year: 2020 | Conference Paper | Volume: 2248 | Publisher: AIP Publishing
H.M.I. Paska; A. Widyaparaga; F. Fauzun; A. Ridwan; R. Abdurrahman
Journal of Mechanical Design and Testing
Year: 2020 | Journal Article | Volume: 2, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: The Solar Chimney Power Plant (SCPP) is an energy conversion system that would absorb solar thermal energy and convert heat air into electrical energy using a collector. The main disadvantage of the SCPP is that low efficiency because less solar heat flux can be converted to the electrical power affected by the design of the SCPP. This study was designed the SCPP by theoretical calculation for producing electrical power and experimented by designing the SCPP use a chimney with divergent shape, a collector with convergent shape, a turbine generator with 3 blades, and coating some materials at the collector’s ground to increasing the electrical power. The purpose of this work was to study about the impact of the solar heat flux ( ) to the temperature of air, to the velocity of air, to the power electricity and compare between power generated from theoretical calculations design and the experiments result. The result showed that the SCPP with the optimized design affect the performance of the SCPP’s output power. The power generated in this experiment is 0.1 Watt. That value is greater than output power from theoretical calculations about 42.8% for the same input solar heat flux ( ) 1118 W/m2 both for theoritical and experimental.
Deendarlianto; A. Widyaparaga; T. Widodo; I. Handika; I. Chandra Setiawan; A. Lindasista
Renewable Energy
Year: 2020 | Journal Article | Volume: 146 | Publisher: Elsevier BV
H.S. R; K. Diharjo; P. Setyono; I.M. Miasa
International Journal of Recent Engineering Science
Year: 2020 | Journal Article | Volume: 6, Issue: 1 | Publisher: Seventh Sense Research Group Journals
N.B. Miasa; S.M. Apitsa
Palgrave Studies of Internationalization in Emerging Markets
Year: 2020 | Book Chapter | Publisher: Springer International Publishing
B. Arifvianto; M. Mahardika; U.A. Salim; S. Suyitno
Key Engineering Materials
Year: 2020 | Journal Article | Volume: 840 | Publisher: Trans Tech Publications, Ltd.
Abstract: Surface mechanical attrition treatment (SMAT) has been recognized as a potential surface treatment for improving the strength and the wear resistance of magnesium (Mg) and its alloy. However, this treatment potentially increases the degradation rate of these particular materials. Therefore, additional treatments might be needed to overcome such limitation of the SMAT. In this research, the influence of polishing on the degradation of the SMAT-processed AZ31B Mg alloy was investigated. Weight losses measurement and pH monitoring were carried out to determine degradation behavior of the Mg alloy during an immersion test in 3.5 wt.% NaCl solution. The results showed that the degradability of the Mg alloy decreased with the application of polishing to remove the rough surface layer and the Fe contaminant on the material surface generated by the SMAT. Based on all the findings in this work, it can be concluded that the SMAT is indeed a promising technique for lowering the degradability of AZ31B Mg alloy, but such an advantage was masked by the increased roughness and contamination of the alloy surface with this treatment.
B. Arifvianto; M. Mahardika; U.A. Salim; S. Suyitno
Journal of Engineering and Technological Sciences
Year: 2020 | Journal Article | Volume: 52, Issue: 1 | Publisher: The Institute for Research and Community Services (LPPM) ITB
Abstract: In this research, a comparative study was carried out to examine the surface characteristics of medical-grade 316L stainless steel after blasting treatments by using angular silica particles, spherical slag balls and spherical metallic shot. The surface roughness, morphology, elemental composition and microhardness distribution of the stainless steel were determined and the possible mechanisms in the evolution of the surface characteristics of the steel exposed to the blasting treatments were established. The results showed that all the blasting treatments conducted in this research increased the roughness and hardness of the steel surface. In this case, the roughest stainless steel surface was achieved by the slag ball-blasting treatment, but the stainless steel with the hardest surface and the thickest hard subsurface layer was obtained by the shot-blasting treatment. On the basis of the findings in this research it can be concluded that the physical properties and surface morphology of particles or shot used in the blasting treatment are critical parameters in determining the surface characteristics of blasted stainless steel.
I. Yunianto; A.E. Permanasari; W. Widyawan
2020 12th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2020 | Conference Paper | Publisher: IEEE
I.S. Sakkinah; R. Hartanto; A.E. Permanasari
Proceedings of the International Conference on Online and Blended Learning 2019 (ICOBL 2019)
Year: 2020 | Conference Paper | Publisher: Atlantis Press
S.K. Prilistya; A. Erna Permanasari; S. Fauziati
2020 12th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2020 | Conference Paper | Publisher: IEEE
F.W. Nugraha; S. Fauziati; A.E. Permanasari
2020 Third International Conference on Vocational Education and Electrical Engineering (ICVEE)
Year: 2020 | Conference Paper | Publisher: IEEE
A.E. Permanasari; M. Wisaksono; S.S. Kusumawardani
IJITEE (International Journal of Information Technology and Electrical Engineering)
Year: 2020 | Journal Article | Volume: 3, Issue: 4 | Publisher: Universitas Gadjah Mada
Abstract: Senior high school students need to select a specialization, such as Mathematics and Natural Sciences, Social Sciences, or Language and Culture. This selection process can be improved by using Multi Criteria Decision Making (MCDM) methods. When MCDM methods are implemented, AHP method has accuracy of 61%, whereas AHP-Fuzzy TOPSIS 1 and AHP-Fuzzy TOPSIS 2 have accuracy of 75%. This research implements tests and analyzes new MCDM method, which is Hybrid MCDM Model, in helping aforementioned specialization selection process. There are four basic steps in Hybrid MCDM Model: performing experimental design to obtain attributes' weight and criteria, evaluating MCDM with the three existing methods, performing RSM regression to derive mathematical model, and decision making. This research introduces data normalization to the mathematical model which results in better implementation of Hybrid MCDM Model in the senior high school students' specialization selection process. Hybrid MCDM Model in the senior high school student specialization selection has accuracy of 86%, which includes 11% accuracy improvements compared to other applied MCDM methods.
A. Wijaya; T.B. Adji; N.A. Setiawan
Communications in Science and Technology
Year: 2020 | Journal Article | Volume: 5, Issue: 2 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
Abstract: The multi-class motor imagery based on Electroencephalogram (EEG) signals in Brain-Computer Interface (BCI) systems still face challenges, such as inconsistent accuracy and low classification performance due to inter-subject dependent. Therefore, this study aims to improve multi-class EEG-motor imagery using two-stage detection and voting scheme on one-versus-one approach. The EEG signal used to carry out this research was extracted through a statistical measure of narrow window sliding. Furthermore, inter and cross-subject schemes were investigated on BCI competition IV-Dataset 2a to evaluate the effectiveness of the proposed method. The experimental results showed that the proposed method produced enhanced inter and cross-subject kappa coefficient values of 0.78 and 0.68, respectively, with a low standard deviation of 0.1 for both schemes. These results further indicated that the proposed method has an ability to address inter-subject dependent for promising and reliable BCI systems.
M.A. Manhar; I. Soesanti; N.A. Setiawan
Journal FORTEI-JEERI
Year: 2020 | Journal Article | Volume: 1, Issue: 1 | Publisher: Journal FORTEI-JEERI, Forum Pendidikan Tinggi Teknik Elektro Indonesia
Abstract: Coronary artery disease (CAD) is one of the deadliest diseases in the entire world, including in Indonesia. CAD occurs due to narrowing or blockage of coronary arteries which is usually caused by atherosclerosis. Various studies have been conducted with the aim to predict the nature and characteristics of this disease. Some researches uses the Z-Alizadeh Sani dataset which consists of 54 attributes with two results of classification, CAD and Normal to classify its data. Feature selection is one way to reduce the number of attributes that exist by leaving the attributes that have a high effect on the dataset. In this study, the Boruta method is used as a feature selection to minimize the attributes and leave the attributes with high relative with the dataset. By reducing the attributes in the dataset through the feature selection process, sets of 17 and 18 attributes are selected as attributes with high relative with the dataset. These attributes then used to calculate the accuracy value of the dataset using the several classification methods and 90,3% accuracy is obtained from this study.
H. Ulfatriyani; H.A. Nugroho; I. Soesanti
2020 3rd International Conference on Information and Communications Technology (ICOIACT)
Year: 2020 | Conference Paper | Publisher: IEEE
A. Nugroho; R. Hidayat; H. Adi Nugroho; J. Debayle
Journal of Physics: Conference Series
Year: 2020 | Journal Article | Volume: 1444, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
Ultrasound is widely utilized in radiological screening to achieve early cancer investigations. Alongside this utilization, the need of object detection and segmentation techniques highly increases as crucial procedure of computer aided diagnosis tool. In addition, the industrial revolution 4.0 also demands automation and digitization in every technological development including computer aided diagnosis systems. This paper presents a morphological region-based active contour called MoRbAC to automatically detect the cancerous objects. Global level set active contour is initially employed to quick segment all objects in the whole image. Inhomogeneity in ultrasound images will lead to erroneous segmentation result. Hence, several morphology operations are taken to enhance it. The cancerous objects are then specifically detected by comparative calculation of area similarity. The proposed MoRbAC was tested in the real ultrasound images of breast and thyroid which validated by manual ground truth localization. Measurements of overlapping and disagreement regions are applied as quantitative indexes to demonstrate its performance. Average values of each validation has achieved i.e accuracy 98.58±0.89%, sensitivity 89.58±7.69%, specificity 99.58±0.11%, precision 95.58±2.77%, similarity 92.36±4.67%. In conclusion, the high performance of MoRbAC indicates its potential for practical applications in ultrasound computer aided diagnosis.
I. Wijayanto; R. Hartanto; H.A. Nugroho
2020 3rd International Conference on Information and Communications Technology (ICOIACT)
Year: 2020 | Conference Paper | Publisher: IEEE
I. Wijayanto; R. Hartanto; H.A. Nugroho
Informatics in Medicine Unlocked
Year: 2020 | Journal Article | Volume: 19 | Publisher: Elsevier BV
A. Kusumaatmaja; P. Mulyono
E3S Web of Conferences
Year: 2020 | Journal Article | Volume: 200 | Publisher: EDP Sciences
H. Susilowati; P. Mulyono
BIO Web of Conferences
Year: 2020 | Journal Article | Volume: 28 | Publisher: EDP Sciences
D. Retno Sawitri; P. Mulyono; Rochmadi; A. Budiman
IOP Conference Series: Materials Science and Engineering
Year: 2020 | Journal Article | Volume: 778, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
Epoxidation of unsaturated fatty materials is useful route to synthesize valuable material especially bio-based polymers. Oleic acid (OA, iodine value of 90 gram I2/100 gram) is the most common unsaturated fatty material that can be found in vegetable oils or animal fats. Epoxidation of oleic acid with peracetic acid generated in-situ has been performed in batch system. Kinetic evaluation was conducted by varying the reaction temperature from 40 to 70 °C under constant value of stirring speed, H2O2:OA molar ratio, acetic acid:OA molar ratio, and catalyst concentration. Double bond conversion, oxirane yield, and selectivity of oxirane has been evaluated. The result shows that the degree of side reaction (ie: ring opening) is high in temperature of 60 and 70 °C. Pseudo-homogeneous kinetic model is well fitted in 40 and 50 °C but it gives significant deviation in 60 and 70 °C. The activation energy of oleic acid epoxidation has been found to be 62.2 kJ/mol.
D.R. Sawitri; P. Mulyono; Rochmadi; A. Hisyam; A. Budiman
Journal of Oleo Science
Year: 2020 | Journal Article | Volume: 69, Issue: 10 | Publisher: Japan Oil Chemists' Society
M. Setyawan; P. Mulyono; S. Sutijan; Y.S. Pradana; L. Prasakti; A. Budiman
International Journal of Renewable Energy Development
Year: 2020 | Journal Article | Volume: 9, Issue: 3 | Publisher: Center of Biomass and Renewable Energy Scientia Academy
Abstract: Previous studies of biodiesel production from microalgae have concluded that microalgal biodiesel is not profitable at an industrial scale due to its excessive energy consumption for lipid extraction. Hydrodynamic cavitation lipid extraction is one of the extraction methods which has lower energy consumption. Thismethod enables a fast extraction rate and low energy consumption for cell disruption. In order to achieve optimum process conditions, several influential parameters, which are cavitation generator geometry and driving pressure, need to be scrutinized. The experimental result showed that the maximum yield was obtained at 5 bar driving pressure. The lowest specific extraction energy was obtained at 4.167 bar driving pressure while using one side concave cavitation generator geometry with the ratio of the reduced cross-sectional area of 0.39. The value of the energy extraction requirement 17.79 kJoule/g lipids is less than the biodiesel heating value, and the value of the volumetric mass transfer coefficient is almost 20 times fold greater than the conventional extraction method, therefore this method is promising to be further developed.
I. Trisnawati; G. Prameswara; P. Mulyono; A. Prasetya; H.T.B.M. Petrus
International Journal of Technology
Year: 2020 | Journal Article | Volume: 11, Issue: 4 | Publisher: International Journal of Technology
Sabrina; S. Wibirama; I. Ardiyanto
2019 Asia Pacific Conference on Research in Industrial and Systems Engineering (APCoRISE)
Year: 2019 | Conference Paper | Publisher: IEEE
S. Sugiyanto; S. Kamal; J. Waluyo; A. Widyaparaga
Advances in Science, Technology and Engineering Systems Journal
Year: 2019 | Journal Article | Volume: 4, Issue: 5 | Publisher: ASTES Journal
Deendarlianto; A. Rahmandhika; A. Widyatama; O. Dinaryanto; A. Widyaparaga; Indarto
International Journal of Heat and Mass Transfer
Year: 2019 | Journal Article | Volume: 130 | Publisher: Elsevier BV
Deendarlianto; I. Supraba; A.I. Majid; M.R. Pradecta; Indarto; A. Widyaparaga
Case Studies in Thermal Engineering
Year: 2019 | Journal Article | Volume: 13 | Publisher: Elsevier BV
Anderiansyah; I.M. Miasa
Journal of Physics: Conference Series
Year: 2019 | Journal Article | Volume: 1351, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
This article proposes a model for a real-time monitoring system capable of identifying the occurrence of single event leak in pressurized water pipelines. The model utilizes two accelerometers which are installed on upstream and downstream of the leak. Experiments are conducted on an inch PVC pipeline and the vibration signal results are displayed and recorded into laptop with installed software. The vibration signal derived from each accelerometer are assessed and analysed by Fast Fourier Transformation (FFT) and Cross-Power Spectral Density (CPSD). The results indicate that by using this method, leak can be identified while the sensor’s positioning can be vital in leak detection.
M.B. Reksono; I.M. Miasa
Journal of Physics: Conference Series
Year: 2019 | Journal Article | Volume: 1351, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
The goal of this research was to gather knowledge and to analyze the problem of excessive vibration level of Gas Turbine Generator (GTG) 100 MW system installed in cogeneration power plant in Sumatra Island, Indonesia which supports one of biggest oil and gas industries in Indonesia. The case research related to vibration problem were presented to diagnosis the main causes of excessive vibration that occur in the gas turbine generator during operation. Vibration analysis is one of the most important activities in predictive maintenance. Vibration monitoring system and machinery diagnostic technical specification are presented. The vibration data of this research were collected using online vibration monitoring system Bently Nevada 3500 series and system 1® display software at different bearing locations during transient (shutdown & start-up and steady state (on-line) condition. Assessment on overall vibration levels shall refer to Original Equipment Manufacturer (OEM) alert & danger set points, as well as relevant ISO 20816-2 standard. Finally, recommendation of reducing excessive vibration level is provided to ensure safe and reliable operation of the GTG unit.
A.P. Wijayanto; I. Made Miasa
Journal of Physics: Conference Series
Year: 2019 | Journal Article | Volume: 1351, Issue: 1 | Publisher: IOP Publishing
Abstract: Abstract
A method for detecting leaks in plastic water supply pipes through analysis of the pipe’s surface vibration using an accelerometer is proposed. Various diameter of leaks and distance of leaks are examined. The method involves identification of the changes vibration spectrum in Fast Fourier Transform (FFT) diagram caused on the pipe by various leak scenario. It is showing that FFT diagram on pipe small leak is difficult to be distinguished with FFT diagram with pipe no leak scenario. However, pipe big leak shows narrow frequency dominant in FFT diagram with high values on acceleration. The further leakage points from accelerometer, trend of frequency dominant in the FFT diagram is getting lower.
I.M. Miasa; S. Sucipto; A. Wiranata; S. Alfarizki; N.C. Majid
Journal of Mechanical Design and Testing
Year: 2019 | Journal Article | Volume: 1, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: Sistem perpipaan sangat penting di dunia industri, khususnya industri yang berkaitan dengan fluida seperti industi minyak dan gas. Beberapa gangguan dalam suatu proses produksi atau distribusi sering terjadi akibat adanya permasalahan dalam sistem perpipaan. Salah satu masalah serius di dalam sistem perpipaan adalah getaran akibat aliran dari fluida (flow-induced vibration). Masalah getaran ini bila tidak ditangani secara benar akan menyebabkan kerusakan pada struktur sistem perpipaan dan komponen-komponen yang terkait seperti pompa atau mesin-mesin fluida lainnya. Pada penelitian ini, pengaruh dari karakteristik fluida dan jenis tumpuan pada pola getar (mode shape) akan diinvestigasi secara eksperimental. Karakteristik fluida dinyatakan dalam fraksi udara dan cairan. Dua jenis tumpuan pipa yaitu simply supported dan clamped supported secara detail diinvestigasi. Mode shape dari getaran pipa yang terjadi diukur sebagai fungsi dari karakteristik fluida dan jenis tumpuan. Hasil pengukuran secara eksperimental selanjutnya dibandingkan dengan hasil simulasi yang dilakukan dengan Finite Element Analysis. Hasil dari penelitian ini menunjukkan bahwa clamped support membuat pipa bergetar dengan frekuensi yang lebih tinggi, sedangkan aliran fluida dengan fraksi cairan yang lebih tinggi memberikan level getaran yang lebih tinggi.
B. Arifvianto; Suyitno; M. Mahardika
Materials Science Forum
Year: 2019 | Journal Article | Volume: 948 | Publisher: Trans Tech Publications, Ltd.
Abstract: Surface mechanical attrition treatment (SMAT) has so far been used as a technique for improving mechanical and tribological properties of magnesium and its alloys. However, the effects of the SMAT on corrosion and degradability of these materials are still rarely reported in open literature. In this research, the degradation behavior of AZ31B magnesium alloy after receiving the SMAT was characterized. The degradation behavior of the Mg alloy was determined from the weight losses after an immersion test for 24 h in 3.5 wt.% NaCl solution. During the test, the pH of the solution was also monitored. The results obviously showed higher corrosion rates of the Mg alloy that had been treated by using the SMAT. Interestingly, the degradation rate of the Mg alloy decreased once a longer duration of SMAT was applied. Meanwhile, the pH of NaCl solution increased up to 12 and 13.9 once the non-treated and the SMAT specimens were immersed into the solution, respectively. In addition, the energy dispersive X-ray spectroscopy (EDS) analysis confirmed the presence of corrosion products in all the Mg samples that were similar to those revealed in the literature.
Ardiansyah; R. Ferdiana; A.E. Permanasari
2019 International Conference on Advanced Computer Science and information Systems (ICACSIS)
Year: 2019 | Conference Paper | Publisher: IEEE
F. Setianingsih; A.E. Permanasari; W. Najib
IJITEE (International Journal of Information Technology and Electrical Engineering)
Year: 2019 | Journal Article | Volume: 3, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Abstract— Prof. Soeparwi Veterinary Hospital is one of veterinary medical service providers in Yogyakarta ad Central Java areas in which the transaction and the documentation managing process is still done manually. Therefore, Prof. Soeparwi VH needs a management information system that facilitate them in managing process and documentation of transactions, one of which is through billing or billing subsystem. This subsystem was designed using UML and was developed in a form of web-based prototype using PHP and HTML languages as well as CSS with CodeIgniter framework and MySQL for database. The development of this billing subsystem applied a Rapid Application Development (RAD) model process that focused on the working model and obtained feedback from users to improve the system. Results of this system's development were evaluated with a system feasibility test and functionality test. A system feasibility test was administered by distributing Likert scale questionnaire and analysed them based on a summated rating scale method which showed a result of 85.4%. That result indicates that users strongly agree that the system has met their needs. The system functionality was tested using a black box method and the result was that the system properly functioned. This billing subsystem could process transaction bills automatically included in the calculation. This system produced bills and reports that could be printed and exported. In addition, data was stored in a database so that it supported paperless documentation.
E.H. Budiarto; A. Erna Permanasari; S. Fauziati
2019 5th International Conference on Science and Technology (ICST)
Year: 2019 | Conference Paper | Publisher: IEEE
I. Hidayah; A.E. Permanasari; N. Woro Wijayanti
2019 5th International Conference on Science and Technology (ICST)
Year: 2019 | Conference Paper | Publisher: IEEE
M.F. Lathief; I. Soesanti; A.E. Permanasari
Proceedings of the International Conference on Creative Economics, Tourism and Information Management
Year: 2019 | Conference Paper | Publisher: SCITEPRESS - Science and Technology Publications
S. Murnani; S. Wibirama; N.A. Setiawan
2019 5th International Conference on Science and Technology (ICST)
Year: 2019 | Conference Paper | Publisher: IEEE
T.G. Pratama; R. Hartanto; N.A. Setiawan
Communications in Science and Technology
Year: 2019 | Journal Article | Volume: 4, Issue: 2 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
Abstract: Autism Spectrum Disorder (ASD) classification using machine learning can help parents, caregivers, psychiatrists, and patients to obtain the results of early detection of ASD. In this study, the dataset used is the autism-spectrum quotient for child, adolescent and adult, namely AQ-child, AQ-adolescent, AQ-adult. This study aims to improve the sensitivity and specificity of previous studies so that the classification results of ASD are better characterized by the reduced misclassification. The algorithm applied in this study: support vector machine (SVM), random forest (RF), artificial neural network (ANN). The evaluation results using 10-fold cross validation showed that RF succeeded in producing higher adult AQ sensitivity, which was 87.89%. The increase in the specificity level of AQ-Adolescents is better produced using an SVM of 86.33%.
A. Nugroho; R. Hidayat; H.A. Nugroho
2019 5th International Conference on Science and Technology (ICST)
Year: 2019 | Conference Paper | Publisher: IEEE
A. Nugroho; R. Hidayat; H.A. Nugroho
Proceedings of the 3rd International Conference on Cryptography, Security and Privacy
Year: 2019 | Conference Paper | Publisher: ACM
A. Achban; H.A. Nugroho; P. Nugroho
2019 5th International Conference on Science and Technology (ICST)
Year: 2019 | Conference Paper | Publisher: IEEE
A. Rizal; R. Hidayat; H.A. Nugroho
Indonesian Journal of Electrical Engineering and Informatics (IJEEI)
Year: 2019 | Journal Article | Volume: 7, Issue: 2 | Publisher: IAES Indonesia Section
A. Rachman; R. Hidayat; H.A. Nugroho
Jurnal Edukasi dan Penelitian Informatika (JEPIN)
Year: 2019 | Journal Article | Volume: 5, Issue: 2 | Publisher: Tanjungpura University
Abstract: Saat ini teknologi animasi gerak bibir tengah berkembang secara signifikan seiring dengan perkembangan industri kreatif. Metode yang sering digunakan untuk membuat gerak bibir tersebut adalah peta fonem ke visem. Pembangunan peta fonem ke visem awalnya mengacu pada ketentuan baku susunan fonem yang sudah ada, namun kemudian susunan ini berkembang mengikuti kebutuhan. Fonem vokal mengambil peran terbesar karena energi percakapan terakumulasi padanya. Variasi pengucapan vokal yang sangat beragam menyebabkan susunan keberadaan fonem vokal pada peta juga beragam. Keragaman ini berimplikasi pada akurasi peta fonem ke visem yang juga berujung pada akurasi gerak bibir animasi. Paper ini membahas tentang signifikansi perbedaan tiga macam nada vokal /e/ Bahasa Indonesia baik dari ciri audio maupun dari ciri visual untuk menunjang susunan baku vokal pada peta fonem ke visem. Metode yang digunakan adalah filter LPC untuk mengekstraksi ciri frekuensi forman, Par-CLR untuk mengekstraksi ciri visual, hingga uji statistik untuk mengetahui signifikansi perbedaan. Hasilnya menunjukkan sebagian nada tersebut memiliki perbedaan signifikan satu sama lain. Sehingga peta fonem ke visem akan lebih akurat jika menyertakan unsur ketiga /e/ tersebut.
I. Haitami; P. Mulyono; M. Hidayat
Konversi
Year: 2019 | Journal Article | Volume: 7, Issue: 2 | Publisher: Center for Journal Management and Publication, Lambung Mangkurat University
Abstract: Abstrak - Limbah cair yang mengandung Cr(III) dan Na secara bersamaan sering dijumpai pada hasil kegiatan industri, terutama industri penyamakan kulit. Cr(III) yang merupakan logam berbahaya harus dapat dihilangkan dari limbah cair tersebut. Salah satu metode yang efektif digunakan untuk menangani pencemaran Cr(III) dalam limbah cair adalah pertukaran ion menggunakan resin penukar ion. Prinsip metode ini, yaitu menukarkan ion yang tersedia pada resin penukar ion dengan ion-ion yang berada di sekitarnya. Kehadiran Na dalam larutan tempat dijerapnya Cr(III) dengan menggunakan Amberlite IR-120 H, membuat fenomena ini tergolong sebagai penjerapan multikomponen. Dalam hal ini, penjerapan Cr(III) dan Na oleh Amberlite IR-120 H terjadi secara bersama-sama (simultan). Penelitian ini bertujuan untuk mempelajari laju penjerapan simultan yang terjadi pada berbagai suhu. Di samping itu, ingin dikembangkan model matematis untuk mendekati kinetika penjerapan simultan yang ada. Hasil penelitian menunjukkan bahwa semakin tinggi suhu, maka akan semakin besar laju penjerapan simultan Cr(III) dan Na. Kecenderungan yang sama ditunjukkan oleh nilai konstanta kinetika yang semakin besar seiring meningkatnya suhu. Model matematis yang disusun berdasarkan persamaan laju reaksi cukup sesuai untuk mendekati kinetika penjerapan simultan ini. Berdasarkan nilai energi aktivasi sebesar 56,735 kJ/mol untuk penjerapan Cr(III) yang terjadi, maka dapat dikatakan bahwa laju reaksi adalah laju yang mengontrol proses.Kata kunci: Kromium(III), penjerapan, kinetika, Amberlite IR-120 H, simultan
Herlina; S. Wibirama; I. Ardiyanto
2018 International Conference on Information and Communications Technology (ICOIACT)
Year: 2018 | Conference Paper | Publisher: IEEE
L. Lyta; I. Ardiyanto; S. Wibirama
2018 4th International Conference on Science and Technology (ICST)
Year: 2018 | Conference Paper | Publisher: IEEE
R. Kurnia; R. Ferdiana; S. Wibirama
2018 International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2018 | Conference Paper | Publisher: IEEE
C. Ramdani; I. Soesanti; S. Wibirama
IJITEE (International Journal of Information Technology and Electrical Engineering)
Year: 2018 | Journal Article | Volume: 1, Issue: 4 | Publisher: Universitas Gadjah Mada
Abstract: Fuzzy C Means algorithm or FCM is one of many clustering algorithms that has better accuracy to solve problems related to segmentation. Its application is almost in every aspects of life and many disciplines of science. However, this algorithm has some shortcomings, one of them is the large amount of processing time consumption. This research conducted mainly to do an analysis about the effect of segmentation parameters towards processing time in sequential and parallel. The other goal is to reduce the processing time of segmentation process using parallel approach. Parallel processing applied on Nvidia GeForce GT540M GPU using CUDA v8.0 framework. The experiment conducted on natural RGB color image sized 256x256 and 512x512. The settings of segmentation parameter values were done as follows, weight in range (2-3), number of iteration (50-150), number of cluster (2-8), and error tolerance or epsilon (0.1 – 1e-06). The results obtained by this research as follows, parallel processing time is faster 4.5 times than sequential time with similarity level of image segmentations generated both of processing types is 100%. The influence of segmentation parameter values towards processing times in sequential and parallel can be concluded as follows, the greater value of weight parameter then the sequential processing time becomes short, however it has no effects on parallel processing time. For iteration and cluster parameters, the greater their values will make processing time consuming in sequential and parallel become large. Meanwhile the epsilon parameter has no effect or has an unpredictable tendency on both of processing time.
M.A. Putra; N.A. Setiawan; S. Wibirama
Communication in Science and Technology
Year: 2018 | Journal Article | Volume: 3, Issue: 2 | Publisher: Komunitas Ilmuwan dan Profesional Muslim Indonesia (KIPMI)
P.E. Suryadana; S. Wibirama; I. Ardiyanto
2018 International Conference on Computer Engineering, Network and Intelligent Multimedia (CENIM)
Year: 2018 | Conference Paper | Publisher: IEEE
S. Wibirama; H.A. Nugroho; K. Hamamoto
Entertainment Computing
Year: 2018 | Journal Article | Volume: 26 | Publisher: Elsevier BV
P.V.N. Nugraha; S. Wibirama; R. Hidayat
2018 International Conference on Information and Communications Technology (ICOIACT)
Year: 2018 | Conference Paper | Publisher: IEEE
P. Pranowo; A. Widyaparaga
Modelling and Simulation in Engineering
Year: 2018 | Journal Article | Volume: 2018 | Publisher: Wiley
Abstract: This paper describes a numerical model based on discontinuous Galerkin method for thermoacoustic investigation. Numerical investigation was conducted to study the behaviour of thermoacoustic wave propagations induced by thermal effects in 2-dimensional enclosure. The compressible Navier-Stokes equations are used as the governing equations. The spatial domain was discretized by using unstructured discontinuous Galerkin method and the explicit fourth-order Runge-Kutta was used to integrate the temporal domain. The accuracy of the numerical results was assessed against other numerical methods and linear solutions. The comparisons with linear solutions show excellent agreement and comparisons with flux corrected transport (FCT) method show fair agreement.
P. Sudarmono; Deendarlianto; A. Widyaparaga
Journal of Physics: Conference Series
Year: 2018 | Journal Article | Volume: 1022 | Publisher: IOP Publishing
I. Aditya Dharma; A. Widyaparaga; A. Yuandia
Teknoin
Year: 2018 | Journal Article | Volume: 24, Issue: 1 | Publisher: Universitas Islam Indonesia (Islamic University of Indonesia)
Sugiyanto; S. Kamal; J. Waluyo; A. Widyaparaga
2018 4th International Conference on Science and Technology (ICST)
Year: 2018 | Conference Paper | Publisher: IEEE
Sudarja; F. Jayadi; Indarto; Deendarlianto; A. Widyaparaga
AIP Conference Proceedings
Year: 2018 | Conference Paper | Volume: 2005 | Publisher: Author(s)
Sudarja; A. Haq; Deendarlianto; Indarto; A. Widyaparaga
Journal of Hydrodynamics
Year: 2018 | Journal Article | Volume: 31, Issue: 1 | Publisher: Springer Science and Business Media LLC
I.A. Dharma; A. Widyaparaga; I. Pranoto; Khasani
AIP Conference Proceedings
Year: 2018 | Conference Paper | Volume: 2005 | Publisher: Author(s)
F. Prihandoto; A. Widyaparaga; J. Waluyo; S. Kamal; Sugiyanto
AIP Conference Proceedings
Year: 2018 | Conference Paper | Volume: 2005 | Publisher: Author(s)
E.S. Sijabat; A. Widyaparaga; J. Waluyo; S. Kamal; Sugiyanto
AIP Conference Proceedings
Year: 2018 | Conference Paper | Volume: 2005 | Publisher: Author(s)
B. Surono; R. Sriwijaya; I.M. Miasa
2018 12th South East Asian Technical University Consortium (SEATUC)
Year: 2018 | Conference Paper | Publisher: IEEE
R. Sriwijaya; F.F. Muhammad; M.A. Gaffar; T.P. Purwanto; I.M. Miasa
2018 12th South East Asian Technical University Consortium (SEATUC)
Year: 2018 | Conference Paper | Publisher: IEEE
R.A. Anugrah; A. Widyaparaga; I.M. Miasa; J. Waluyo; Sugiyanto; S. Kamal
AIP Conference Proceedings
Year: 2018 | Conference Paper | Volume: 2005 | Publisher: Author(s)
M. Mahardika; R.A. Wicaksono; M.G. Widiastuti; B. Arifvianto; -. Suyitno
International Journal on Advanced Science, Engineering and Information Technology
Year: 2018 | Journal Article | Volume: 8, Issue: 3 | Publisher: Insight Society
B. Kharsananda; A.E. Permanasari; S. Fauziati
2018 International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2018 | Conference Paper | Publisher: IEEE
Y.E. Kurniawati; A.E. Permanasari; S. Fauziati
2018 4th International Conference on Science and Technology (ICST)
Year: 2018 | Conference Paper | Publisher: IEEE
A. Erna Permanasari; S. Fauziati; A. Kartika Candri
MATEC Web of Conferences
Year: 2018 | Journal Article | Volume: 248 | Publisher: EDP Sciences
Abstract: Given the large volume of data generated in hospitals, the usage of hospital information system (HIS) that may ease the hospital’s workload on managing patient bills is critical. Thus, this paper presents the development of a web based hospital billing system which allows the staffs to manage and store patient bills in such a way that it can integrate bills from various departments. In addition to that, the system has additional features to allow down payments, automatically generate accounting reports, as well as integrate some features of the registration and the pharmacy system. The system design followed the Waterfall approach and was done using the use case diagram, activity diagram, sequence diagram, and entity relationship diagram. The data processed was actual data from the hospital and dummy data for the pharmacy system. The system’s functionality was tested using the black-box method and then evaluated by the hospital staffs using the SUS (System Usability Scale) method. From there, we obtained a score of 77.5 out of 100 from the SUS evaluation and 100% success rate from 102 features tested with the black-box testing method. Therefore, we can conclude that the new system works well and has good usability.
I.K. Hildayanti; I. Soesanti; A.E. Permanasari
2018 International Seminar on Research of Information Technology and Intelligent Systems (ISRITI)
Year: 2018 | Conference Paper | Publisher: IEEE
M.T. Setiawan; S. Wibirama; N.A. Setiawan
2018 4th International Conference on Science and Technology (ICST)
Year: 2018 | Conference Paper | Publisher: IEEE
Sutedi; T.B. Adji; N.A. Setiawan
2018 International Conference on Applied Information Technology and Innovation (ICAITI)
Year: 2018 | Conference Paper | Publisher: IEEE
H. Lalin; I.W. Mustika; N.A. Setiawan
ETRI Journal
Year: 2018 | Journal Article | Volume: 40, Issue: 6 | Publisher: Wiley
B. Nugroho; I. Ardiyanto; H.A. Nugroho
2018 2nd International Conference on Biomedical Engineering (IBIOMED)
Year: 2018 | Conference Paper | Publisher: IEEE
A. Rizal; R. Hidayat; H.A. Nugroho
Indonesian Journal of Electrical Engineering and Computer Science
Year: 2018 | Journal Article | Volume: 12, Issue: 3 | Publisher: Institute of Advanced Engineering and Science
Abstract: <p><em>Lung sound is a biological signal used to determine the health level of the respiratory tract. Various digital signal processing techniques have been developed for the automatic lung sound classification. Entropy is one of the parameters used to measure the biomedical signal complexity. Multiscale entropy is introduced to measure the entropy of a signal at a particular scale range. Over time, various multiscale entropy techniques are used to measure the signal complexity on biological signal and other physical signals. In this paper, a number of multiscale entropy techniques for the lung sound classification are discussed. The results showed that Multiscale Permutation Entropy (MPE) could produce the highest accuracy of 97.98% for five classes of lung sound data. Results achieved for the scale 1-10 producing ten features for each lung sound data. This result is better than other seven entropies. The use of Permutation entropy (PE) on a multiscale scheme was to obtain a better accuracy compared to PE on one scale only</em><em> </em></p>
A. Rizal; R. Hidayat; H.A. Nugroho
2018 4th International Conference on Science and Technology (ICST)
Year: 2018 | Conference Paper | Publisher: IEEE
A. Rizal; H.A. Nugroho; R. Hidayat
Journal of Computer Science
Year: 2018 | Journal Article | Volume: 14, Issue: 8 | Publisher: Science Publications
A. Rizal; R. Hidayat; H.A. Nugroho
International Journal of Advances in Intelligent Informatics
Year: 2018 | Journal Article | Volume: 4, Issue: 3 | Publisher: Universitas Ahmad Dahlan
Abstract: Abnormalities in the lungs can be detected from the sound produced by the lungs. Diseases that occur in the lungs or respiratory tract can produce a distinctive lung sound. One of the examples of the lung sound is the pulmonary crackle caused by pneumonia or chronic bronchitis. Various digital signal processing techniques are developed to detect pulmonary crackle sound automatically, such as the measurement of signal complexity using Tsallis entropy (TE). In this study, TE measurements were performed through several orders on the multiscale pulmonary crackle signal. The pulmonary crackle signal was decomposed using the coarse-grained procedure since the lung sound as the biological signal had a multiscale property. In this paper, we used 21 pulmonary crackle sound and 22 normal lung sound for the experiment. The results showed that the second order TE on the scale of 1-15 had the highest accuracy of 97.67%. This result was better compared to the use of multi-order TE from the previous study, which resulted in an accuracy of 95.35%.
P. Mulyono
Jurnal Teknik Kimia Indonesia
Year: 2018 | Journal Article | Volume: 7, Issue: 1 | Publisher: The Institute for Research and Community Services (LPPM) ITB
Abstract: Copper has been extracted by trtbuthyl phosphate-kerosene from a dilute aqueous solution with a double- stage mixer-settler extraction column. The extraction column used in this experiment was made of glass. The mixer diameter was equal to the diameter of settler was 13 cm. Both the mixer and settler heights were 8 cm. Drop coalescer was mounted in the middle of mixer and settler separator. The diameter of drop coalescer was 6 cm with the thickness of 1 cm. The hole diameter of drop coalescer was 1 mm The stirrer used in this experiment was cross flat blade with the diameter and width of the impeller was 6 cm and 8 mm, respectively. The overall volumetric coefficient of mass transfer (Kca) increased by increasing the flowrate of the continuous phase (Lc) at the constants stirring speed (N) and flowrate of the dispersed phase (Ld). The increase of Lc from 4.1634 cm3/second to 17.9436 cm3/second increased the Kca value from 6.6387x10-5/second to 23.1561x10-5/second or 248.8% The value of Kca was also increase by increasing N at the constant values of Lc and Ld Thie increase of N from 3.3333 rps to 8.3333 rps increased the Kca value from 6.0288x10-5/second to 6.6387x10-5/second or 10.1%.Keywords: Mass Transfer Coefficient, Extraction, Copper, Double-Stage Mixer-SettlerAbstrak Penelitian ini mempelajari perpindahan massa antar fasa pada ekstraksi Cu dart larutan CuSO4.5H2O dengan menggunakan pelarut tributyl phosphate dalam kerosin yang dilakukan dalam kolom ekstraksi double-stage mixer-settler yang dtsusun vertikal. Kolom ekstraksi mixer-settler dibuat darti gelas dengan diameter mixer sama dengan diameter sealer, yaitu 13 cm. Tinggi mixer juga sama dengan tinggt settler, yaitu 8 cm. Diameter drop coalescer 8 cm, tebal 1 cm, dan diameter lubangnya 1 mm. Pengaduk yang digunakan berbentuk flat blade dengan diameter 6 cm dan lebar blade 8 mm. Koeftsien perpindahan massa volumetris keseluruhan (Kca) naik dengan naiknya kecepatan alir fasa kontinyu (Lc) pada kecepatan putaran pengaduk (N) dan kecepatan alir fasa dispersi (Ld) tetap. Kenatkan nilai Lc dart 4,1634 cm3/detik menjadi 17,9436 cm3/detik meningkatkan nilai Kca dart 6,6387x10-5/detik menjadi 23,1561x10-5/detik atau 248,8% Kca juga naik dengan naiknya N pada Lc dan Ld yang tetap. Kenaikan nilai N dart 3,3333 rps menjadi 8,3333 rps meningkatkan nilai Kca dart 6,0288x10-5/detik menjadt 6,6387x10-5/detik atau 10,1%.Kata Kunci : Koefesien Perpindahan Massa, Ekstraksi, Tembaga, Double-Stage Mixer-Settler
I. Fadlilah; A. Prasetya; P. Mulyono
Jurnal Rekayasa Proses
Year: 2018 | Journal Article | Volume: 12, Issue: 1 | Publisher: Universitas Gadjah Mada
Abstract: Unlicensed gold mining activities (PETI) using mercury (Hg) as a gold element binder is called the amalgamation process. Mercury is a heavy metal toxic. The use of mercury can potentially cause pollution in environment, especially the aquatic environment. For overcoming the heavy metals mercury in liquid waste, it needs an alternative wastewater treatment method called chemical precipitation. This study is aimed to recover Hg2+ ions from liquid wastes by using sulphide precipitation and hydroxide methods. This research studied the effect of pH on Hg ions which is deposited in the precipitation process and found out the rate of Hg precipitation formation. Precipitation was done by using sodium sulphide (Na2S) 0.3 M and Ca(OH)2 0.004 M as a precipitation agent with rapid mixing speed for about 200 rpm for 3 minutes and continued with slow mixing for about 40 rpm for 30 minutes. Then, just let the liquid sample be for 24 hours to precipate the precipitate formed. The results show that precipitation method by using a Na2S solution can decrease the content of Hg in HgCl2 synthetic waste. An optimum mass of HgS precipitate of 0,0458 g was achieved pH 9 for 200 mL of wastewater liquid with a removal efficiency percentage up to 99.81%. The concentration of mercury can be derived from 130 ppm to 0.25 ppm. The rate of formation of HgS precipitate was obtained 0.0004g/ hour. While, hydroxide precipitation method can decrease mercury level up to 90,11% at pH 12 and mass of Hg (OH)2 precipitate obtained is 0,2784 g. However, the result of EDX analysis of the precipitate of Hg (OH)2 shows that the content of Hg precipitate is just 0.281%.
M.R. Ulya; I. Perdana; P. Mulyono
Jurnal Rekayasa Proses
Year: 2018 | Journal Article | Volume: 11, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Konsentrasi yang tinggi dari kelarutan silika dalam larutan geothermal menyebabkan masalah dalam pengoperasian produksi uap di PLTP Dieng. Mitigasi silika scaling diperlukan untuk mengurangi resiko kegagalan produksi uap. Dalam penelitian ini, asam silika dalam larutan geothermal direaksikan dengan kalsium hidroksida (Ca(OH)2) membentuk n ano calcium silicate (NCS). Tujuan penelitian ini adalah membentuk endapan NCS dari surfaktan SLS dan Ca(OH)2 ke dalam larutan geothermal. Mempelajari perubahan suhu (30, 50 dan 70°C), pH (7, 8 dan 9), dan konsentrasi surfaktan (0,05, 0,15 and 0,30% (w/v) serta mengetahui kondisi optimum. Pengujian yang dilakukan yaitu pengendapan partikel yang dilakukan di gelas ukur vertical, densitas padatan, densitas larutan, viskositas, dan diameter rata-rata partikel yang mengendap ditentukan dari persamaan diameter stokes. Kemudian membandingkan hasil perhitungan dari diameter stokes dengan particle size analyzer (PSA). Konsentrasi silika yang terlarut dapat diukur dengan metode spectroscopy dan komposisi padatan di uji dengan instrumen EDX dan FTIR. Hasil penelitian menunjukkan bahwa silika terlarut dalam larutan geothermal berkurang dan dapat dikontrol dengan penambahan Ca(OH)2 dan penambahan surfaktan SLS. Semakin besar konsentrasi surfaktan maka ukuran partikel akan semakin kecil. Pembentukan NCS dapat dihasilkan dan disertai juga dengan partikel silika dan garam. Kondisi optimum pembentukan NCS terjadi pada suhu 30 oC pH 9 dan konsentrasi surfaktan SLS 0,30 %w/v.
M. Setyawan; P. Mulyono; Sutijan; A. Budiman
MATEC Web of Conferences
Year: 2018 | Journal Article | Volume: 154 | Publisher: EDP Sciences
Abstract: Biodiesel production from microalgae is one of the solution of the future energy problem, but its production cost is still high. One of the costly stages of this process is the lipid extraction process. It can be reduced by microalgae cell disruption. One of the mechanical method to cell disruption with the lowest energy requirement is hydrodynamic cavitation. This aim of this study is to evaluate the distribution coefficient and the mass transfer coefficient value of lipid extraction of Nannochloropsis sp. assisted by hydrodynamic cavitation and compare with conventional extraction. The hydrodynamic cavitation extraction was done at 34 °C, 1 atm. The conventional extraction was done at 34 °C, 1 atm with stirring speed 260 and 1000 rpm. The experimental result shows that the distribution coefficient dependent on the temperature with the values for 50, 44, 38 and 34 °C were 0.502, 0.394, 0.349, and 0.314 respectively. And it was according to Van’ Hoff equation with the values of ΔH° was 20.718 kJ/mol and ΔS° was 58.05 J/mol/K. The hydrodynamic cavitation extraction was faster than conventional. The mass transfer coefficient values for hydrodynamic cavitation, conventional 260 rpm and 1000 rpm were 7.373, 0.534 and 0.121 1/s respectively.
A.S. Oky; C.W. Purnomo; P. Mulyono
Key Engineering Materials
Year: 2018 | Journal Article | Volume: 789 | Publisher: Trans Tech Publications, Ltd.
Abstract: Slow release fertilizer with pesticide (SRFP) has been formulated to provide nutrientenriched with pesticide using all natural compound. Matrix formulation is used with poultry manure(PM) as the nutrient source as well as the solid matrix for incorporating neem leave (Azadirachtaindica a.juss) and gendarussa leave (Justicia gendarussa burm) extract as the active compounds. Inthis study, the release of nutrient i.e. nitrogen by the addition of the two leave extracts during SRFPpreparation has been investigated using sand bed column leaching test. The leachate solution wasanalysed by Kjedahl method to measure total nitrogen amount released. Different volume of the leaveextract was investigated to study the effect of the extract addition on the release of the nitrogen. It isshown that the higher the volume of the leaves extract added during the granulation process, the fasterthe release of the nutrient.
P. Mulyono; I.M. Bendiyasa; D.B. Wibawa; S. Birowo
Jurnal Teknik Kimia Indonesia
Year: 2018 | Journal Article | Volume: 4, Issue: 3 | Publisher: The Institute for Research and Community Services (LPPM) ITB
Abstract: The volumetric coefficient of heat transfer and the energy storage capacity in a direct contact thermal energy storage system using Na2HPO4.12H2O solution as thermal energy storage medium have been investigated. Hot kerosene was used as a heal transfer fluid. The experiments were carried out by bubbling hot kerosene from the bottom of a column containing Na2HPO4.12H2O solution. The column used in this experiment was made from glass of 3 mm in thickness with an inside diameter of 7 cm and a height of 100 cm. The effects of kerosene flow rate and kerosene bubble diameter on the volumetric coefficient of heat transfer and the storing rate of energy were studied. It was found that the volumetric coefficient of heat transfer was strongly affected by the flow rate of the kerosene and that the effect of the kerosene flow rate on the storing rate of energy was relative v high, while that of the effect of the bubble diameter was neglectable.Keywords: Direct Contact, Thermal Energy Storage System, Na2HPO4.12H2O Solution AbstrakPenelitian ini mempelajari sistem penyimpanan energi panas kontak langsung menggunakan larutan Na2HPO4.12H2O sebagai media penyimpan energi. Kerasin panas digunakan sebagai fluida alir sumber energi panas. Masalah yang dipelajari pada penelitian ini adalah nilai koefisien perpindahan panas volumetris dan kapasitas penyimpanan panasnya. Percobaan dilakukan dengan menggelembungkan kerasin panas dari dasar kolom yang berisi larutan Na2HPO4.12H2O. Kolom yang digunakan dibuat dari gelas dengan ketebalan 3 mm, mempunyai diameter dalam 7 cm, dan tinggi kolomnya adalah 100 cm. Parameter yang dipelajari dalam penelitian ini adalah pengaruh kecepatan volumetris kerosin dan pengaruh diameter gelembung kerosin terhadap nilai koefisien perpindahan panas volumetris dan terhadap kecepatan penyimpanan panasnya. Hasil penelitian menunjukkan bahwa nilai koejisien perpindahan panas volumetris sangat dipengaruhi oleh kecepatan volumetris kerosin sehingga kecepatan penyimpanan panasnya juga sangat dipengaruhi oleh kecepatan volumetris kerosin. Pengaruh ukuran diameter gelembung terhadap nilai koefisien perpindahan panas volumetris dan terhadap kecepatan penyimpanan panasnya sangat kecil sehingga dapat diabaikan.Kata Kunci: Sistem Penyimpanan Energi Panas, Kontak Langsung, Larutan Na2HPO4.12H2O
S. Sunarno; R. Rochmadi; P. Mulyono; M. Aziz; A. Budiman
BioResources
Year: 2018 | Journal Article | Volume: 13, Issue: 1 | Publisher: BioResources
C.W. Purnomo; A. Respito; E.P. Sitanggang; P. Mulyono
Environmental Technology & Innovation
Year: 2018 | Journal Article | Volume: 10 | Publisher: Elsevier BV
P. Mulyono; I.M. Bendiyasa; S. Sarto; T. Mustika; H. Heriyanto
Jurnal Teknik Kimia Indonesia
Year: 2018 | Journal Article | Volume: 5, Issue: 1 | Publisher: The Institute for Research and Community Services (LPPM) ITB
Abstract: Copper is one of the hazardous materials and is found in some industrial waste waters. Extraction is thought to be an effective removal technique for copper from dilute solution. In this study, copper has been extracted by tributhyl phosphate-kerosene from a dilute aqueous solution with a double-stage mixer-settler extraction column. The extraction column used in this experiment was made of glass. The mixer diameter was equal to the diameter of settler was 13 cm. Both the mixer and settler heights were 8 cm. Drop coalescer was mounted in the middle of mixer and settler separator. The diameter of drop coalescer was 6 cm with the thickness of 1 cm. The hole diameter of drop coalescer was 1 mm. The stirrer used in this experiment was cross flat blade with the diameter and width of the impeller was 6 cm and 8 mm, respectively. The overall volumetric coefficient of mass transfer (Kca) increased by increasing the flow rate of the continuous phase (Lo) at the constants stirring speed (N) and flow rate of the dispersed phase (Ld). The increase of Lc from 4.1634 cm3/second to 17.9436 cm3 /second increased the Kca value from 6.6387x10-5/second to 23.1561x 10-5 /second or 248.8%. The value of Kca was also increase by increasing N at the constant values of Lc and Ld The increase of N from 3.3333 rps to8.3333 rps increased the Kca value from 6.0288x10-5 second to 6.6387x10-5 second or 10.1%.Keywords: Mass Transfer Coefficient, Extraction, Copper, Double-stage Mixer-settler AbstrakTembaga (Cu) merupakan logam berat yang bila terbuang ke lingkungan merupakan zat pencemar yang berbahaya. Ekstraksi dapat digunakan dengan efektif untuk memungut Cu dari limbah cair walaupun dalam konsentrasi yang rendah. Penelitian ini mempelajari perpindahan massa antarfasa pada ekstraksi Cu dari larutan CuSO4.5H2O dengan menggunakan pelarut tributyl phosphate dalam kerasin yang dilakukan dalam kolom ekstraksi double-stage mixer-settler yang disusun vertikal. Kolom ekstraksi mixer-settler dibuat dari gelas dengan diameter mixer dan diameter settler 13 cm. Tinggi mixer 8 cm. Diameter drop coalescer 8 cm, tebal 1 cm, dan diameter lubangnya 1 mm. Pengaduk yang digunakan berbentuk flat blade dengan diameter 6 cm dan lebar blade 8 mm. Koefisien perpindahan massa volumetris keseluruhan (Kca) naik dengan naiknya kecepatan alir fasa kontinyu (Lc) pada kecepatan putaran pengaduk (N) dan kecepatan alir fasa dispersi (Ld) tetap. Kenaikan nilai Lc dari 4,1634 cm3/detik menjadi 17,9436 cm3/detik meningkatkan nilai Kca dari 6,6387x10-5/detik menjadi 23,1561x10-5/detik atau 248,8%. Kca juga naik dengan naiknya N pada Lc dan Ld yang tetap. Kenaikan nilai N dari 3,3333 rps menjadi 8,3333 rps meningkatkan nilai K.adari 6,0288x10-5 detik menjadi 6,6387x10-5 detik atau 10,1%.Kata Kunci: Koefisien Perpindahan Massa, Ekstraksi, Tembaga, Double-stage Mixer-settler
S. Wibirama; H.A. Nugroho
2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)
Year: 2017 | Conference Paper | Publisher: IEEE
Noprianto; S. Wibirama; H.A. Nugroho
2017 3rd International Conference on Science and Technology - Computer (ICST)
Year: 2017 | Conference Paper | Publisher: IEEE
M. Pratama; N.A. Setiawan; S. Wibirama
2017 7th International Annual Engineering Seminar (InAES)
Year: 2017 | Conference Paper | Publisher: IEEE
G.S. Nugraha; I. Soesanti; S. Wibirama
Advanced Science Letters
Year: 2017 | Journal Article | Volume: 23, Issue: 3 | Publisher: American Scientific Publishers
P.V. Yulianandra; S. Wibirama; P.I. Santosa
2017 1st International Conference on Informatics and Computational Sciences (ICICoS)
Year: 2017 | Conference Paper | Publisher: IEEE
A.E. Permanasari; A. Nurlayli
2017 International Conference on Sustainable Information Engineering and Technology (SIET)
Year: 2017 | Conference Paper | Publisher: IEEE
M. Abobaker; S. Sulistyo; A.E. Permanasari
Respati
Year: 2017 | Journal Article | Volume: 9, Issue: 27 | Publisher: Pusat Penelitian dan Pengabdian Pada Masyarakat Universitas Respati Yogyakarta
Abstract: The health care system in Libya in recent years does not change significantly, less developed and modernized. This problem is further exacerbated by the revolution that occurred in Libya. The revolution that occurred in 2011 has caused the health care system into collapse. In this study conducted a review for the development of health information systems in Libya by using OpenMRS Framework.At the stage of gathering information using questionnaires concluded that the majority of respondents (about 95.35%) wanted the development of a new system that can resolve the main problems that occurred in Libya, the health information system ineffective and inefficient in which this system has led to wastage of time and increased operating costs. Based on analysis of system vulnerabilities using PIECES method could also be concluded that the current system is not used effectively and efficiently. In this study is also presented on how to implement OpenMRS.Based on the results of the discussion it can be concluded that OpenMRS is a solution that can be taken for the development of a health information system that is fast, low cost, and is an open source application that only requires a little setting in the system of patient management and care. OpenMRS can be implemented to support the health services of a small clinic to the health services with enterprise scale. Therefore, OpenMRS could be the answer to the development of health information systems in various countries around the world, including Libya.
A.E. Permanasari; W. Najib; R.R. Kusuma
2017 International Symposium on Geoinformatics (ISyG)
Year: 2017 | Conference Paper | Publisher: IEEE
L. Rahman; N.A. Setiawan; A.E. Permanasari
2017 2nd International conferences on Information Technology, Information Systems and Electrical Engineering (ICITISEE)
Year: 2017 | Conference Paper | Publisher: IEEE
Maryam; N.A. Setiawan; O. Wahyunggoro
AIP Conference Proceedings
Year: 2017 | Conference Paper | Volume: 1867 | Publisher: Author(s)
Y. Pristyanto; N.A. Setiawan; I. Ardiyanto
2017 1st International Conference on Informatics and Computational Sciences (ICICoS)
Year: 2017 | Conference Paper | Publisher: IEEE
Asroni; N.A. Setiawan; S.S. Kusumawardani
ICoSI 2014
Year: 2017 | Book Chapter | Publisher: Springer Singapore
R. Ferizal; S. Wibirama; N.A. Setiawan
2017 7th International Annual Engineering Seminar (InAES)
Year: 2017 | Conference Paper | Publisher: IEEE
Sutedi; T.B. Adji; N.A. Setiawan
2017 International Conference on Signals and Systems (ICSigSys)
Year: 2017 | Conference Paper | Publisher: IEEE
K.A. Utama; E. Nugroho; N.A. Setiawan
Jurnal Buana Informatika
Year: 2017 | Journal Article | Volume: 8, Issue: 2 | Publisher: Universitas Atma Jaya Yogyakarta
Abstract: Abstract.Hedonic motivation, which is often called as intrinsic motivation, plays a role in encouraging a person to use a system to meet their needs. Currently, the popular systems used in the fulfilment of one's needs are games and social media. It has been recorded that the users of Instagram, which has been ranked as the second most popular social media in America, has increased as many as 100 thousand people since the middle of 2016, with the total registered users of 600 million. This development raises a question of what drives a person to use social media. This study aims to identify factors that affect a person to use Instagram based on Hedonic Motivation System Adoption Model (HMSAM). The data were then analyzed using Partial Least Square (PLS). After the research was conducted on 245 respondents, the results prove that the motivating factors of a person to use Instagram are perceived ease of use, perceived enjoyment, and control.Keywords: hedonic motivation system adoption system (hmsam), structural equation model (sem), partial least square (pls), social media, instagram. Abstrak.Motivasi hedonis atau sering kali juga disebut dengan motivasi intrinsik berperan dalam mendorong seseorang untuk menggunakan suatu sistem demi memenuhi kebutuhannya. Saat ini sistem yang populer digunakan dalam pemenuhan kebutuhan seseorang tersebut adalah game dan social media. Instagram yang menduduki peringkat ke dua sebagai social media terpopuler di Amerika, tercatat mengalami pertumbuhan sebanyak 100 ribu orang sejak pertengahan 2016 dengan total pengguna yang tercatat sebanyak 600 juta orang. Melihat perkembangan tersebut memunculkan pertanyaan apa yang mendorong seseorang untuk menggunakan sosial media. Penelitian ini akan melihat faktor yang mempengaruhi seseorang menggunakan Instagram berdasarkan Hedonic Motivation System Adoption Model (HMSAM) yang kemudian dianalisis menggunakan metode Partial Least Square (PLS). Hasilnya setelah dilakukan penelitian pada 245 responden terbukti bahwa yang menjadi faktor pendorong seseorang menggunakan Instagram adalah percieve ease of use, percieved enjoyment, dan control.Kata Kunci: hedonic motivation system adoption system (hmsam), structural equation model (sem), partial least square (pls), social media, instagram.
H.A. Nugroho
2017 4th International Conference on Electrical Engineering, Computer Science and Informatics (EECSI)
Year: 2017 | Conference Paper | Publisher: IEEE
H.A. Nugroho
Proceeding of the Electrical Engineering Computer Science and Informatics
Year: 2017 | Journal Article | Volume: 4, Issue: 1 | Publisher: Institute of Advanced Engineering and Science
A. Rizal; R. Hidayat; H.A. Nugroho
2017 International Conference on Robotics, Automation and Sciences (ICORAS)
Year: 2017 | Conference Paper | Publisher: IEEE
A. Rachman; R. Hidayat; H.A. Nugroho
2017 4th International Conference on Electrical Engineering, Computer Science and Informatics (EECSI)
Year: 2017 | Conference Paper | Publisher: IEEE
A. Rizal; R. Hidayat; H.A. Nugroho
Far East Journal of Electronics and Communications
Year: 2017 | Journal Article | Volume: 17, Issue: 5 | Publisher: Pushpa Publishing House
Sunarno; S. Herman; Rochmadi; P. Mulyono; A. Budiman
AIP Conference Proceedings
Year: 2017 | Conference Paper | Volume: 1821 | Publisher: Author(s)
R. Wicaksono; E. Firmansyah; B.S.M. Isnaeni
2016 8th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2016 | Conference Paper | Publisher: IEEE
S. Wibirama
2016 1st International Conference on Biomedical Engineering (IBIOMED)
Year: 2016 | Conference Paper | Publisher: IEEE
F. Nurwanto; I. Ardiyanto; S. Wibirama
2016 8th International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2016 | Conference Paper | Publisher: IEEE
T. Satriya; S. Wibirama; I. Ardiyanto
2016 International Symposium on Electronics and Smart Devices (ISESD)
Year: 2016 | Conference Paper | Publisher: IEEE
Deendarlianto; M. Andrianto; A. Widyaparaga; O. Dinaryanto; Khasani; Indarto
Journal of Petroleum Science and Engineering
Year: 2016 | Journal Article | Volume: 147 | Publisher: Elsevier BV
M.E. Yuniza; A. Widyaparaga; R. Wicaksono; P.S. Krisnadevi
The Journal of World Energy Law & Business
Year: 2016 | Journal Article | Volume: 9, Issue: 5 | Publisher: Oxford University Press (OUP)
P. Murti; I. Setiawan; A. Widyaparaga; A.B.S. Utomo; M. Nohtomi
AIP Conference Proceedings
Year: 2016 | Conference Paper | Volume: 1741 | Publisher: Author(s)
I.A. Dharma; F. Arffan; A.R. Prambudi; A. Widyaparaga; I. Pranoto; Khasani
AIP Conference Proceedings
Year: 2016 | Conference Paper | Volume: 1737 | Publisher: Author(s)
K.Y. Putri; A.E. Permanasari; S. Fauziati
2016 1st International Conference on Biomedical Engineering (IBIOMED)
Year: 2016 | Conference Paper | Publisher: IEEE
R.A. Hamid; R. Hartanto; A.E. Permanasari
Prosiding Sains Nasional dan Teknologi
Year: 2016 | Journal Article | Volume: 1, Issue: 1 | Publisher: Fakultas Teknik Universitas Wahid Hasyim
Abstract: Pemanfaatan media penyimpan di kalangan pendidikan, khususnya pendidikan menengah kebawah masih mengandalkan satu perangkat yang digunakan saja. Perangkat yang digunakan tersebut masih juga berfungsi untuk bekerja sehari-hari. Pengembangan media simpan dengan memanfaatkan jaringan masih sebatas beberapa perangkat saja, itupun hanya bisa diakses dalam satu lokasi saja. Rancang bangun cloud data center di sekolah ini bertujuan untuk membuat bank data sekolah yang bisa diakses melalui jaringan internet. Bank data sekolah tersebut akan tersimpan di server yang ada disekolah. Dengan pengaturan jadwal akan tersalin otomatis ke server cloud yang ada di jaringan global internet. Seluruh perangkat dan infrastruktur di sekolah akan terhubung dan terintegrasi dalam satu jaringan lokal sekolah dan jaringan internet. Peningkatan produkstifitas dalam bekerja dibutuhkan sistem yang akan melayani penyimpanan data dan pelayanan salinan data otomatis akan memberikan manfaat besar untuk sekolah. Guru dan siswa akan lebih intensif dalam melakukan proses pembelajaran baik secara online maupun offline. Semua data sekolah maupun data materi pembelajaran tersedia secara online dan bisa dihadirkan secara fisik. Lebih lanjut rancang bangun cloud data center disekolah ini bisa dikembangkan untuk berbagai layanan pendidikan yang lain. Kata Kunci: Cloud data server , Integrasi, Media simpan
F. Dzikrullah; N.A. Setiawan; S. Sulistyo
2016 6th International Annual Engineering Seminar (InAES)
Year: 2016 | Conference Paper | Publisher: IEEE
R. Septiana; I. Soesanti; N.A. Setiawan
2016 4th International Conference on Cyber and IT Service Management
Year: 2016 | Conference Paper | Publisher: IEEE
S. .; T.B. Adji; H.A. Nugroho
Conference SENATIK STT Adisutjipto Yogyakarta
Year: 2016 | Journal Article | Volume: 2 | Publisher: Institut Teknologi Dirgantara Adisutjipto (ITDA)
Triwiyanto; O. Wahyunggoro; H.A. Nugroho; Herianto
2016 International Seminar on Application for Technology of Information and Communication (ISemantic)
Year: 2016 | Conference Paper | Publisher: IEEE
A. Adiningtyas; P. Mulyono
Jurnal Rekayasa Proses
Year: 2016 | Journal Article | Volume: 10, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: The adsorption kinetics of nickel (II) in aqueous solution with activated carbon from coconut shell was studied by measuring the nickel concentration in the solution (C) as a function of time (t). The parameters studied in this study were adsorption temperature (T), particle diameter of activated carbon (d), and mass ratio of activated carbon to aqueous solution (r). It was found that the adsorption rate increased with the increase of the adsorption temperature and the mass ratio of activated carbon to aqueous solution. On the contrary, it was found that the rate of adsorption decreased with increasing the particle diameter of the activated carbon. Keywords: adsorption kinetic, nickel (II), activated carbon, coconut shell Kinetika adsorpsi larutan nikel (II) dalam air dengan karbon aktif tempurung kelapa dianalisis dengan mengukur konsentrasi nikel pada larutan sebagai fungsi waktu. Parameter yang digunakan pada penelitian ini adalah suhu adsorpsi (T), diameter partikel karbon aktif tempurung kelapa (d), dan rasio massa karbon aktif tempurung kelapa dengan larutan nikel (II) dalam air (r). Hasil penelitian menunjukkan bahwa laju adsorpsi meningkat dengan bertambahnya suhu adsorpsi dan rasio massa karbon aktif tempurung kelapa dengan larutan. Sedangkan, laju adsorpsi menurun dengan bertambahnya ukuran diameter partikel karbon aktif tempurung kelapa. Kata kunci: kinetika adsorpsi, nikel (II), karbon aktif, tempurung kelapa
Sunarno; Rochmadi; P. Mulyono; A. Budiman
AIP Conference Proceedings
Year: 2016 | Conference Paper | Volume: 1737 | Publisher: Author(s)
D.S. Fardhyanti; W.B. Sediawan; P. Mulyono; M. Hidayat
PONTE International Scientific Researchs Journal
Year: 2016 | Journal Article | Volume: 72, Issue: 9 | Publisher: Ponte Academic Journal
H. PH; A.A. Setiawan; A. Widyaparaga
ASEAN Journal of Systems Engineering
Year: 2015 | Journal Article | Volume: 3, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Gunung Kidul coastal is an area that has varying heights up to 250 meters above sea level, and dealing directly with the Indian Ocean. Based on the location of the height of the sea surface, with Logarithmic formulation of wind speed, Gunung Kidul coastal has a varying energy class. The method used is an analytical model of constant density atmospheric, assuming that the density of the air from sea level to the top of the atmosphere has a fixed value. Furthermore, the value of wind speed is used as a probability distribution function based on the data period of 24.5 years. The results of the average value of wind energy are grouped according to energy class. On the use of the Poisson probability distribution, the class of potential good of energy is reached at a height of over 450 meters above sea level. While the use of the Normal distribution and Weibull reach potential class good at 100 meters above sea level.
U. Karyani; P. Mulyono; I.M. Miasa
ASEAN Journal of Systems Engineering
Year: 2015 | Journal Article | Volume: 3, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: The purpose of this research is to make juicer machine to produce vegetable milk for small and medium-scale industries, and the machine has been able to be made with a juicer machine dimensions 90 cm X 40 cm X 114 cm. With ½ HP motor power and motor speed 1420 r / min so as to grind soy beans, green beans and corn with a production capacity of each of the milk is on average 15 liters, 12 liters and 12 liters.The first study is to design and create a juicer machine to produce vegetable milk based soy bean, green beans and corn by using some filter size is 60 mesh, 80 mesh and 100 mesh to obtain a best filter size for each type of vegetable milk. And organoleptic test to determine the level of preference for vegetable milk and obtained the most preferred type of vegetable milk is soy milk with a 100 mesh filter.Anti-E.coli test result on vegetable milk as product quality standards, not found any E. coli in each sample tested. While the feasibility of vegetable milk production using a juicer machine is feasible to use in the business of making the three types of vegetable milk because it can give the advantage of 1.20-fold for each unit of the issued capital, the benefits outweigh the effort of making industrial scale vegetable milk usual household. And in terms of the market, producing vegetable milk is still a promising business seen from vegetable milk organoleptic test average of 60% is still loved and considers it important to consume vegetable milk.
S. Diwandari; A.E. Permanasari; I. Hidayah
2015 International Seminar on Intelligent Technology and Its Applications (ISITIA)
Year: 2015 | Conference Paper | Publisher: IEEE
A. Kharista; A.E. Permanasari; I. Hidayah
2015 International Seminar on Intelligent Technology and Its Applications (ISITIA)
Year: 2015 | Conference Paper | Publisher: IEEE
A. Nugroho; H.A. Nugroho; L. Choridah
2015 International Conference on Science in Information Technology (ICSITech)
Year: 2015 | Conference Paper | Publisher: IEEE
H.A. Nugroho; A. Nugroho; L. Choridah
2015 International Conference on Quality in Research (QiR)
Year: 2015 | Conference Paper | Publisher: IEEE
H. Pujiharsono; H.A. Nugroho; O. Wahyunggoro
2015 International Conference on Science in Information Technology (ICSITech)
Year: 2015 | Conference Paper | Publisher: IEEE
A. Rizal; R. Hidayat; H.A. Nugroho
Journal of Computer Science
Year: 2015 | Journal Article | Volume: 11, Issue: 10 | Publisher: Science Publications
D. Fardhyanti; W. Sediawan; P. Mulyono
British Journal of Applied Science & Technology
Year: 2015 | Journal Article | Volume: 8, Issue: 5 | Publisher: Sciencedomain International
Jumina; D. Siswanta; M. Anggraeni; M.I.D. Mardjan; P. Mulyono; K. Ohto
Asian Journal of Chemistry
Year: 2015 | Journal Article | Volume: 27, Issue: 6 | Publisher: Asian Journal of Chemistry
E. Firmansyah; F.D. Wijaya; W.P.R. Aditya; R. Wicaksono
2014 International Conference on Electrical Engineering and Computer Science (ICEECS)
Year: 2014 | Conference Paper | Publisher: IEEE
S. Wibirama; K. Hamamoto
IEEJ Transactions on Electronics, Information and Systems
Year: 2014 | Journal Article | Volume: 134, Issue: 3 | Publisher: Institute of Electrical Engineers of Japan (IEE Japan)
S. Wibirama; K. Hamamoto
2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Year: 2014 | Conference Paper | Publisher: IEEE
T. HIROMATSU; T. KOSHIMIZU; A. WIDYAPARAGA; M. KOHNO; Y. TAKATA
The Proceedings of the Symposium on Stirlling Cycle
Year: 2014 | Journal Article | Volume: 2014.17, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
B. Arifvianto; J. Zhou
Materials
Year: 2014 | Journal Article | Volume: 7, Issue: 5 | Publisher: MDPI AG
Abstract: Bone tissue engineering has been increasingly studied as an alternative approach to bone defect reconstruction. In this approach, new bone cells are stimulated to grow and heal the defect with the aid of a scaffold that serves as a medium for bone cell formation and growth. Scaffolds made of metallic materials have preferably been chosen for bone tissue engineering applications where load-bearing capacities are required, considering the superior mechanical properties possessed by this type of materials to those of polymeric and ceramic materials. The space holder method has been recognized as one of the viable methods for the fabrication of metallic biomedical scaffolds. In this method, temporary powder particles, namely space holder, are devised as a pore former for scaffolds. In general, the whole scaffold fabrication process with the space holder method can be divided into four main steps: (i) mixing of metal matrix powder and space-holding particles; (ii) compaction of granular materials; (iii) removal of space-holding particles; (iv) sintering of porous scaffold preform. In this review, detailed procedures in each of these steps are presented. Technical challenges encountered during scaffold fabrication with this specific method are addressed. In conclusion, strategies are yet to be developed to address problematic issues raised, such as powder segregation, pore inhomogeneity, distortion of pore sizes and shape, uncontrolled shrinkage and contamination.
C.P.B. Randa; A.E. Permanasari
2014 Makassar International Conference on Electrical Engineering and Informatics (MICEEI)
Year: 2014 | Conference Paper | Publisher: IEEE
A.E. Permanasari; I. Hidayah; S. Nugraha
Advanced Science Letters
Year: 2014 | Journal Article | Volume: 20, Issue: 10 | Publisher: American Scientific Publishers
I. Purba; A.E. Permanasari; N.A. Setiawan
2014 Makassar International Conference on Electrical Engineering and Informatics (MICEEI)
Year: 2014 | Conference Paper | Publisher: IEEE
N.A. Setiawan
International Journal of Rough Sets and Data Analysis
Year: 2014 | Journal Article | Volume: 1, Issue: 1 | Publisher: IGI Global Scientific Publishing
Abstract: The objective of this research is to develop an evidence based fuzzy decision support system for the diagnosis of coronary artery disease. The development of decision support system is implemented based on three processing stages: rule generation, rule selection and rule fuzzification. Rough Set Theory (RST) is used to generate the classification rules from training data set. The training data are obtained from University California Irvine (UCI) data repository. Rule selection is conducted by transforming the rules into a decision table based on unseen data set. Furthermore, RST attributes reduction is proposed and applied to select the most important rules. The selected rules are transformed into fuzzy rules based on discretization cuts of numerical input attributes and simple triangular and trapezoidal membership functions. Fuzzy rules weighing is also proposed and applied based on rules support on the training data. The system is validated using UCI heart disease data sets collected from the U.S., Switzerland and Hungary and data set from Ipoh Specialist Hospital Malaysia. The system is verified by three cardiologists. The results show that the system is able to give the approximate possibility of coronary artery blocking.
D. Kurnianto; I. Soesanti; H.A. Nugroho
Jurnal Informatika,Telekomunikasi dan Elektronika
Year: 2014 | Journal Article | Volume: 5, Issue: 2 | Publisher: LPPM Institut Teknologi Telkom Purwokerto
Abstract: <p class="Abstract">Sistem pengenalan identitas personal berdasarkan ciri biometrika adalah suatu sistem pengenalan seseorang berdasarkan pada ciri biometrika yang melekat pada orang tersebut. Iris mata merupakan salah satu ciri biometrik yang handal untuk sistem pengenalan identitas personal. Bagian sistem pengenalan identitas personal berdasarkan biometrik iris yang dianggap paling krusial adalah deteksi lokasi iris, karena akurasi deteksi iris berpengaruh pada tingkat akurasi sistem secara keseluruhan. Lokasi iris pada citra mata dibatasi oleh dua buah lingkaran yang memisahkan antara bagian iris dengan pupil dan sklera. Telah banyak metode-metode yang diusulkan oleh para peneliti untuk menghasilkan deteksi lokasi iris dengan akurat dan cepat. Masalah akurasi, kecepatan waktu eksekusi dan ketahanan terhadap <em>noise</em> merupakan bidang penelitian yang menantang pada deteksi iris. Makalah ini menyajikan metode deteksi iris menggunakan metode <em>black hole</em> dan <em>circle curve fitting</em>. Langkah pertama, mencari batas dalam lingkaran iris yang memisahkan antara daerah iris dan pupil. Dengan metode <em>black hole</em> yang bekerja berdasarkan fakta bahwa lokasi pupil merupakan daerah lingkaran yang paling hitam dan memiliki distribusi nilai intensitas yang seragam, maka lokasi pupil dapat ditentukan dengan teknik pengambangan. Batas lingkaran pupil dapat ditentukan dengan <em>circle curve fitting</em> dari parameter lingkaran daerah pupil. Langkah kedua, mencari batas luar lingkaran iris yang memisahkan antara iris dan sklera. Peta tepi citra iris dicari dengan menggunakan deteksi tepi Canny, kemudian diambil satu komponen tepi arah vertikal yang dapat mewakili batas lingkaran luar iris. Dari komponen tepi tersebut, dihitung jari-jari iris yang berpusat di pusat pupil. Dengan jari-jari iris dan pusat iris maka dapat ditentukan batas luar iris menggunakan <em>circle curve fitting</em>.</p>
S. Wibirama; K. Hamamoto
2013 International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2013 | Conference Paper | Publisher: IEEE
S. Wibirama; K. Hamamoto
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)
Year: 2013 | Conference Paper | Publisher: IEEE
S. Wibirama; S. Tungjitkusolmun; C. Pintavirooj
IEEJ Transactions on Electrical and Electronic Engineering
Year: 2013 | Journal Article | Volume: 8, Issue: 3 | Publisher: Wiley
Abstract: AbstractIn this paper, we suggest a new approach for accurate measurement of three‐dimensional eye movements employing dual‐camera acquisition. Two calibrated mini CCD cameras are used to capture two simultaneous images of one eye. Center‐of‐mass and template‐matching algorithms are utilized to obtain two‐dimensional coordinates of the center of pupil and iris striation. Instead of asking each subject to fulfill intricate calibration steps, a novel and simpler technique to solve geometric distortion is presented by utilizing direct linear transformation (DLT) algorithm which requires only one preliminary calibration procedure for each camera without changing any camera installation. The DLT algorithm is then used to extract three‐dimensional coordinates of the center of the pupil and iris striation from prior two‐dimensional coordinates, allowing the three‐dimensional angular positions of the eye to be computed. Real‐time eyeball visualization based on tracking results is incorporated to help clinicians diagnose eye movements. Experimental results show that our system has high accuracy, as the average errors in the horizontal, vertical, and torsional angular positions were confined to 0.15°, 0.14°, and 0.20°, respectively. Real‐time implementation demonstrates that our system can be used in clinical routines to observe either voluntary or involuntary human eye movements. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A. Widyaparaga; Pranowo
ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels
Year: 2013 | Conference Paper | Publisher: American Society of Mechanical Engineers
Abstract: This study aims to investigate the significance of conjugate heat transfer in the microscale within the slip regime. As within the slip regime the continuum assumption is invalid due to presence of rarefaction effects, the Lattice Boltzmann method (LBM) is employed to overcome the limitations of Navier Stokes based solutions in this regime. We have constructed and compared two case models in which a fluid of higher temperature enters a microchannel. The conditions are set to obtain Knudsen numbers which result in the slip regime being dominant. To investigate the effect of conjugate heat transfer, the two models differed in the aspect that one model did not incorporate conjugate heat transfer and while the other did. The numerical calculation was validated by comparing the velocity profile results to exact theoretical approximations and was found to agree well. The results of comparison of models Case I and Case 2 have shown that temperature profile is affected significantly by conjugate heat transfer. The conjugate heat transfer at the microchannel wall (Case 1) was shown to maintain the initial temperature of fluid longer than compared to a purely isothermal wall (Case 2), thus signifying the importance of the consideration of conjugate heat transfer effects in microfluid models. We have implemented GPU based parallel processing to reduce computation time. The result of the incorporation of GPU processing was found to increase processing speed up to 15 times.
R. Setyanto; K. Diharjo; P. Setyono; I.M. Miasa
Journal of Materials Science Research
Year: 2013 | Journal Article | Volume: 2, Issue: 4 | Publisher: Canadian Center of Science and Education
R.H. Setyanto; K. Diharjo; P. Setyono; I.M. Miasa
2013 Joint International Conference on Rural Information & Communication Technology and Electric-Vehicle Technology (rICT & ICeV-T)
Year: 2013 | Conference Paper | Publisher: IEEE
B. Arifvianto; Suyitno; M. Mahardika
International Journal of Minerals, Metallurgy, and Materials
Year: 2013 | Journal Article | Volume: 20, Issue: 8 | Publisher: Springer Science and Business Media LLC
I. Hidayah; A.E. Permanasari; N. Ratwastuti
2013 International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2013 | Conference Paper | Publisher: IEEE
A.E. Permanasari; I. Hidayah; I.A. Bustoni
2013 International Conference on Information Technology and Electrical Engineering (ICITEE)
Year: 2013 | Conference Paper | Publisher: IEEE
P. Mulyono; A. Pardah
ASEAN Journal of Chemical Engineering
Year: 2013 | Journal Article | Volume: 12, Issue: 2 | Publisher: Universitas Gadjah Mada
Abstract: Extraction of carboxylic acids from dilute aqueous solution using traditional solvents such as ketones, alcohols, ethers, and ester is inefficient because the distribution ratio is rather low. Reactive extraction which exploits reversible chemical complexation is an effective separation process for extraction of carboxylic acids from aqueous streams such as fermentation broths and wastewaters. In the extraction process, selection of the solvent is an important aspect to be considered. Considering its solubility in water, cost and availability, tri-n-butyl phosphate (TBP) seems to be an attractive solvent for the extraction of lactic acid from aqueous solution. The purpose of this experiment is to study the equilibrium of the reactive extraction of lactic acid in aqueous solution with TBP in n-hexane. The parameters studied in this experiment were initial concentration of lactic acid in the aqueous phase, TBP concentration in n-hexane phase, and the extraction temperature. The experiments at ambient temperature were carried out using a separatory funnel, while the experiments at other than ambient temperature were carried out using erlenmeyer flask and water bath shaker to adjust the temperature. In this experiment, the initial concentration of lactic acid was varied from 0.1 to 0.5 gmol/dm3. The range of initial TBP concentrations in n-hexane was 0.1 to 1.0 gmol/dm3 and the extraction temperature range was 283 to 313 K. The experimental results showed that the higher the initial concentration of lactic acid in aqueous solution, the higher the distribution ratio for a fixed TBP concentration and extraction temperature. For a fixed initial concentration of lactic acid in aqueous solution and extraction temperature, the distribution ratio of lactic acid is increased by increasing TBP concentration. The overall equilibrium constants (Kpq) for the experiments using TBP concentration ranging from 0.1 to 1.0 gmol/dm3 at the extraction temperature of 293 K are calculated to be 0.0668 to 0.5144. Kpq for the experiments at the temperature ranging from 283 to 313 K at the initial concentration of lactic acid of 0.2 gmol/L are found to be 0.0122 to 0.8856. The Kpq as a function of temperature (T) in K can be expressed as ln Kpq = 10,596/T - 38.08 with sum of square of error of 0.14.
E. Budiyati; P. Mulyono; S. Purwono
Jurnal Kimia dan Kemasan
Year: 2013 | Journal Article | Volume: 35, Issue: 2 | Publisher: Center For Chemical & Packaging (Balai Besar Kimia & Kemasan)
P. Mulyono; G.M. Amarullah; Z. Arsadduddin
Ifost
Year: 2013 | Conference Paper | Publisher: IEEE
E. Erawati; W.B. Sediawan; P. Mulyono
Jurnal Kimia Terapan Indonesia
Year: 2013 | Journal Article | Volume: 15, Issue: 2 | Publisher: Indonesian Institute of Sciences
Abstract: Bagasse (Saccarum oficinarum L) is a waste of sugar mills that can be utilized for a variety of chemicals. The purposes of this study are to determine the percentage of compounds and physical properties of bio-oil, to determine the effect of variations of particle size and heating rate on the yields of bio-oil. Pyrolysis has been carried out in a reactor made of steel pipe type 5737 with dimension: diameter 7.62 em and a length of 3 7 cm.. The reactor was inserted into the furnace with a diameter of 15.24 em and a length of 40 em. One hundred and fifty grams of bagasse (Saccarum oficinarum L) has been inserted into the reactor without the presence of oxygen at atmospheric pressure. Pyrolysis has been carried out at the particle size of (-20+25) mesh, (-25+30) mesh, (-30+35) mesh, (- 35+40) mesh, and -40 mesh with electrical voltage of 100, 105, 115, and 120 volt. Produced of bio-oil has the following properties: brown color, pH of 2.96 to 3.03, viscosity of 1.3306 to 1.5101 cp, and density of 1.03 to 1.5 g/mL. The largest content of the compound is acetic acid (59, 72%). The highest yields percentage of the particle size is (40,32%) on (-20+25 mesh) with the highest yields percentage of electrical voltage is 38,82% on 105 volt.Keywords : Bagasse, acetic acid, bio-oil, pyrolysis, yields
E. NODA; A. WIDYAPARAGA; T. KOSHIMIZU; M. KOHNO; Y. TAKATA
TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)
Year: 2012 | Journal Article | Volume: 47, Issue: 1 | Publisher: Cryogenic Association of Japan
E. NODA; A. WIDYAPARAGA; T. KOSHIMIZU; N. SAKODA; M. KOHNO; Y. TAKATA
The Proceedings of the National Symposium on Power and Energy Systems
Year: 2012 | Journal Article | Volume: 2012.17, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
M. Mahardika; B. Arifvianto; Suyitno; A. Wibowo; G.S. Prihandana
Procedia Engineering
Year: 2012 | Journal Article | Volume: 50 | Publisher: Elsevier BV
Suyitno; B. Arifvianto; T.D. Widodo; M. Mahardika; P. Dewo; U.A. Salim
International Journal of Minerals, Metallurgy, and Materials
Year: 2012 | Journal Article | Volume: 19, Issue: 12 | Publisher: Springer Science and Business Media LLC
A.E. Permanasari; Wahyuni; W. Najib; Samkhan
2012 International Conference on Computer & Information Science (ICCIS)
Year: 2012 | Conference Paper | Publisher: IEEE
N.A. Setiawan; Sarjiya; Z. Adhiarga
2012 IEEE International Conference on Condition Monitoring and Diagnosis
Year: 2012 | Conference Paper | Publisher: IEEE
A. Widyaparaga; M. Kuwamoto; N. Sakoda; M. Kohno; Y. Takata
Journal of Heat Transfer
Year: 2011 | Journal Article | Volume: 134, Issue: 2 | Publisher: ASME International
Abstract: We have developed a model capable of predicting the performance characteristics of a wiretype Joule–Thomson microcooler intended for use within a cryosurgical probe. Our objective was to be able to predict cold tip temperature, temperature distribution, and cooling power using only inlet gas properties as input variables. To achieve this, the model incorporated gas equations of state to account for changing gas properties due to heat transfer within the heat exchanger and expansion within the capillary. In consideration of inefficiencies, heat in-leak from free convection and radiation was also considered and the use of a 2D axisymmetric finite difference code allowed simulation of axial conduction. To validate simulation results, we have constructed and conducted experiments with two types of microcoolers differing in inner tube material, poly-ether-ether-ketone (PEEK) and stainless steel. The parameters of the experiment were used in the calculations. CO2 was used as the coolant gas for inlet pressures from 0.5 MPa to 2.0 MPa. Heat load trials of up to 550 mW along with unloaded trials were conducted. The temperature measurements show that the model was successfully able to predict the cold tip temperature to a good degree of accuracy and well represent the temperature distribution. For the all PEEK microcooler in a vacuum using 2.0 MPa inlet pressure, the calculations predicted a temperature drop of 57 K and mass flow rate of 19.5 mg/s compared to measured values of 63 K and 19.4 mg/s, therefore, showing that conventional macroscale correlations can hold well for turbulent microscale flow and heat transfer as long as the validity of the assumptions is verified.
E. NODA; T. KOSHIMIZU; A. WIDYAPARAGA; M. KOHNO; Y. TAKATA
The Proceedings of the Symposium on Stirlling Cycle
Year: 2011 | Journal Article | Volume: 2011.14, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
A. Widyaparaga; M. Kuwamoto; E. Noda; N. Sakoda; M. Kohno; Y. Takata
ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, Volume 2
Year: 2011 | Conference Paper | Publisher: ASMEDC
Abstract: In designing a Joule-Thomson microcooler, aiming for a compact size yet maintaining good performance, it is important to find the optimum dimensions of its heat exchanger. We have developed a model capable of predicting the performance characteristics of a wiretype Joule-Thomson microcooler utilizing analytical methods and incorporating changing gas properties via gas equations of state. The model combined the heat exchanger and the JT expander, thus requiring only the inlet gas properties as input. The model results were compared to experimental measurements using C2H4 and N2O as coolant gases. Predicted mass flow rate and temperature drop were in good agreement with the measured values. The long capillary length present in the tested microcooler was revealed to maintain performance of the microcooler for longer heat exchanger lengths due to it functioning as a secondary heat exchanger. Using the calculation results it was possible to correctly estimate the optimum heat exchanger length for C2H4 and for N2O.
A. WIDYAPARAGA; T. KOSHIMIZU; E. NODA; N. SAKODA; M. KOHNO; Y. TAKATA
The Proceedings of the National Symposium on Power and Energy Systems
Year: 2011 | Journal Article | Volume: 2011.16, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
A. Widyaparaga; T. Koshimizu; E. Noda; N. Sakoda; M. Kohno; Y. Takata
Cryogenics
Year: 2011 | Journal Article | Volume: 51, Issue: 10 | Publisher: Elsevier BV
M. Mahardika; G.S. Prihandana; T. Endo; T. Tsujimoto; N. Matsumoto; B. Arifvianto; K. Mitsui
The International Journal of Advanced Manufacturing Technology
Year: 2011 | Journal Article | Volume: 60, Issue: 9-12 | Publisher: Springer Science and Business Media LLC
N.A. Setiawan; P. Venkatachalam; M.A. Fadzil
International Journal of Medical Engineering and Informatics
Year: 2011 | Journal Article | Volume: 3, Issue: 1 | Publisher: Inderscience Publishers
A. Widyaparaga; M. Kuwamoto; N. Sakoda; M. Kohno; Y. Takata
ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels: Parts A and B
Year: 2010 | Conference Paper | Publisher: ASMEDC
Abstract: We have developed a model capable of predicting the performance characteristics of a wiretype Joule-Thomson microcooler intended for use within a cryosurgical probe. Our objective was to be able to predict evaporator temperature, temperature distribution and cooling power using only inlet gas properties as input variables. To achieve this, the model incorporated changing gas properties due to heat transfer within the heat exchanger and isenthalpic expansion within the capillary. In consideration of inefficiencies, heat in-leak from free convection and radiation was also considered and the use of a 2D axisymmetric finite difference code allowed simulation of axial conduction. Two types of microcoolers differing in inner tube material, poly-ether-ether-ketone (PEEK) and stainless steel, were tested and simulated. CO2 was used as the coolant gas in the calculations and experimental trials for inlet pressures from 0.5 MPa to 2.0 MPa. Heat load trials of up to 550 mW along with unloaded trials were conducted. Comparisons to experiments show that the model was successfully able to obtain a good degree of accuracy. For the all PEEK microcooler in a vacuum using 2.0 MPa inlet pressure, the calculations predicted a temperature drop of 57 K and mass flow rate of 19.5 mg/s compared to measured values of 63 K and 19.4 mg/s therefore showing that conventional macroscale correlations can hold well for turbulent microscale flow and heat transfer as long as the validity of the assumptions is verified.
M. Kuwamoto; A. Widyaparaga; N. Sakoda; M. Kohno; Y. Takata
Proceedings of the International Symposium on Innovative Materials for Processes in Energy Systems 2010
Year: 2010 | Conference Paper | Publisher: Research Publishing Services
A. WIDYAPARAGA; M. KUWAMOTO; N. SAKODA; H. KUBOTA; M. KOHNO; Y. TAKATA
The Proceedings of the National Symposium on Power and Energy Systems
Year: 2010 | Journal Article | Volume: 2010.15, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
M. KUWAMOTO; A. WIDYAPARAGA; N. SAKODA; H. KUBOTA; M. KOHNO; Y. TAKATA
The Proceedings of the National Symposium on Power and Energy Systems
Year: 2010 | Journal Article | Volume: 2010.15, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
I.K. Gede Sugita; R. Soekrisno; I. Made Miasa; S. Suyitno
Material Science Research India
Year: 2010 | Journal Article | Volume: 7, Issue: 1 | Publisher: Oriental Scientific Publishing Company
Abstract: The purpose of this study is to investigate the morphology of solidification microstructures 80% Cu-20%Sn on different solidification rate. The commercial pure copper and tin were melted in crucible furnace at temperature 1000oC. The molten metal was casted in permanent moulds which have variation temperature, i.e. 35oC, 200oC, 400oC. The cooling curves of the castings were recorded using a computer aided data acquisition system. The microstructure and mechanical properties of this alloy have been investigated. The results of this research indicate that decreasing the mould temperatures affected on increasing solidification rate that caused to reduce the solidification time. The difference of solidification rate have effected on microstructure morphology. The secondary dendrite arm spacing (SDAS) decreases with increasing solidification rate, the hardness and strength increase correspondingly. The distribution of hardness cast product increased from the center to outside the cast specimens.
A.F.M. Hani; H.A. Nugroho; H. Nugroho
2010 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES)
Year: 2010 | Conference Paper | Publisher: IEEE
A. WIDYAPARAGA; M. KUWAMOTO; N. SAKODA; H. KUBOTA; M. KOHNO; Y. TAKATA
The Proceedings of the Thermal Engineering Conference
Year: 2009 | Journal Article | Volume: 2009, Issue: 0 | Publisher: Japan Society of Mechanical Engineers
B. Arifvianto; Suyitno
International Conference on Instrumentation, Communication, Information Technology, and Biomedical Engineering 2009
Year: 2009 | Conference Paper | Publisher: IEEE
A. Fadzil M. Hani; H. Adi Nugroho
Journal of Biomedical Science and Engineering
Year: 2009 | Journal Article | Volume: 02, Issue: 07 | Publisher: Scientific Research Publishing, Inc.
H.a. Nugroho; D. Ihtatho; H. Nugroho
The MIDAS Journal
Year: 2008 | Journal Article | Publisher: NumFOCUS - Insight Software Consortium (ITK)
Abstract: In CT images, tumors located in a liver are generally identified by intensity difference between tumor and liver. The intensity of the tumor can be lower and or higher than that of the liver. However, the main problem of liver tumor detection from is related to low contrast between tumor and liver intensities. Tumor sometimes presents in a very small dimension and makes the detection even more difficult. In this work, we focus on contrast enhancement of CT images containing liver and tumor based on the histogram processing as a necessary preprocessing for liver tumor identification. Results show that using our proposed method, the contrast of the CT images can be enhanced and results in relatively accurate identification of tumors in the liver.
I.M. MIASA; M. OKUMA
Journal of System Design and Dynamics
Year: 2007 | Journal Article | Volume: 1, Issue: 1 | Publisher: Japan Society of Mechanical Engineers
I.M. MIASA; M. OKUMA; G. KISHIMOTO; T. NAKAHARA
Journal of System Design and Dynamics
Year: 2007 | Journal Article | Volume: 1, Issue: 2 | Publisher: Japan Society of Mechanical Engineers
P. Mulyono; S. Muliati
ASEAN Journal of Chemical Engineering
Year: 2007 | Journal Article | Volume: 7, Issue: 1 & 2 | Publisher: Universitas Gadjah Mada
Abstract: Liquid-liquid mass transfer coefficients for single freely rising drops in the presence of surfactant in an extraction column have been investigated using the system of kerosene-acetic acid-water. The surfactant used in this study was alkyl benzene sulfonate (ABS). The experiments were carried out by bubbling kerosene-acetic acid solution as a series of single drops from the bottom of a column containing water-ABS solution. The column used in this experiment was made from glass of 36 mm inside diameter and constructed of 60, 120, and 180 cm height. The effects of surfactant concentration, column height, and drop diameter on the overall mass transfer coefficient have been studied. The data can all be correlated by Shd = 2.08 x10−5 Red 4.01 We −1.97 (dd / H ) 0.68 with an average deviation of 17.72%. This equation is valid for the ranges of Red from 186.68 to 402.19, We from 0.80 to 3.33, and dd/H from 0.0028 to 0.0105.
N.A. Setiawan
TELKOMNIKA (Telecommunication Computing Electronics and Control)
Year: 2005 | Journal Article | Volume: 3, Issue: 3 | Publisher: Universitas Ahmad Dahlan
S. Akiyama; K. Miasa
Polymer Journal
Year: 1979 | Journal Article | Volume: 11, Issue: 2 | Publisher: Springer Science and Business Media LLC
