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Using a new coefficient conjugate gradient method for solving unconstrained optimization problems
Ranen M. Sulaiman;
Basim A. Hassan
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1642-1648
The conjugate gradient technique is a numerical solution strategy for finding minimization in mathematics. We present a simple, straightforward, efficient, and resilient conjugate gradient technique in this study. To address the convergence difficulty and descent property, the new technique is built on the quadratic model. Under some assumptions, the new improved approach meets the convergence characteristics and the adequate descent criterion. The suggested unique strategy is substantially more efficient than the classic FR method, according to our numerical analysis. The number of function evaluations, iterations and restarts are all included in the numerical results. The computational efficiency of the proposed approach is proved by comparative results.
Improving optical properties of white light-emitting diodes using triple-layer remote structure
Thanh Binh Ly;
Phan Xuan Le
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1242-1250
Inrecent efforts to improve the performance ofwhite light-emitting diode (WLEDs), researchers have focused on angular color uniformity (ACU), an effective index for evaluating the light quality of WLEDs. Inthis article, we also aim for the WLED development by applying three phosphor layers in the remote phosphor structure. The dual-layer phosphor (DLP) remote structure is also included in the research for comparison with the triple-layer phosphor (TLP) in terms of their impacts on the lighting quality of WLEDs. To ensure the diversity and applicability in different scenarios, performancesof multi-layer phosphor structures in WLED devices with average correlatedcolor temperatures (ACCTs) from 5600 K to 8500K are measured. The experimental results have proved that both TLP and DLP structures are suitable to enhance WLEDs’ performance as each structure excels at specific qualities. In particular, at all ACCTs, the DLP structure is getting better in improvingthe color rendering index (CRI), while the TLP is more advantageous to color quality scale (CQS) and light output. The TLP also presents a lower color deviation than the DLP does, which leads to a better color uniformity in WLEDs at all ACCTs.
Ca8MgY(PO4)7:Eu2+,Mn2+ for better angular chromatic harmony and high lumen for white diode
Phuc Dang Huu;
Phung Ton That;
Phan Xuan Le;
Nguyen Le Thai
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1297-1303
The multifunctional phosphor Ca8MgY(PO4)7doping with Eu2+ and Mn2+ ions (CaMn) is utilized to stimulate the rate of light extraction and color harmony of the white light-emitting diode (WLED) package using remote phosphor design with two sheets of phosphor. The CaMn sheet helps to reduce the color variation and light scattering backward mainly caused by high concentration of yellow phosphor YAG:Ce3+ film. The experimental results show a gradual increase of luminous flux and significant reduction of chromatic deviation in direct proportion to the increasing concentration of CaMn phosphor. Meanwhile, with more than 9% wt of CaMn concentration, the reduction of color rendering properties is presented because of the redundant green emission, leading to the lack of blue and yellow emission energies. Good color quality scale that peaks at 63 can be achieved with 2-4%wt. CaMn in the WLED packages. It is advisable to manage the concentration the green phosphor CaMn to attain desirable optical objectives.
Cloud computing security for e-learning during COVID-19 pandemic
Yassen AbdelKhaleq Najm;
Suray Alsamaraee;
Ahmed Adeeb Jalal
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1610-1618
The demand for e-learning services increased during the developments of the COVID-19 virus and its rapid spread, and the recommendations of the World Health Organization (WHO) that social distancing should be required. The rapid transition to the e-learning environment quickly led to the neglect of some security aspects, which led to an increase in cyber attacks targeting computer accounts, which is one of the most important pillars of e-learning. In these papers, the attacks that target the cloud computer used in the most important e-learning have been studied and classified according to the victim using an inductive methodology based on global statistics related to cyber attacks and recent research. And suggest appropriate solutions to avoid its occurrence in the near future and raise the level of protection for those computer clouds.
A Ppreliminary study on the intelligent model of k-nearest neighbor for agarwood oil quality grading
Siti Mariatul Hazwa Mohd Huzir;
Noratikah Zawani Mahabob;
Aqib Fawwaz Mohd Amidon;
Nurlaila Ismail;
Zakiah Mohd Yusoff;
Mohd Nasir Taib
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1358-1365
Essential oils extracted from trees has various usages like perfumes, incense, aromatherapy and traditional medicine which increase their popularity in global market. In Malaysia, the recognition system for identifying the essential oil quality still does not reach its standard since mostly graded by using human sensory evaluation. However, previous researchers discovered new modern techniques to present the quality of essential oils by analyse the chemical compounds. Agarwood essential oil had been chosen for the proposed integrated intelligent models with the implementation of k-nearest neighbor (k-NN) due to the high demand and an expensive natural raw world resource. k-NN with Euclidean distance metrics had better performance in terms of its confusion matrix, sensitivity, precision accuracy and specificity. This paper presents an overview of essential oils as well as their previous analysis technique. The review on k-NN is done to prove the technique is compatible for future research studies based on its performance.
Development of a low-cost teleoperated and semi-autonomous robotic arm
Megat Satria Zainuddin Yaacob;
Jamaludin Jalani;
Amirul Syafiq Sadun;
Abang Muhammad Zaid Abang Zulkarnain
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1338-1346
A safe human-robot physical interaction is required when the robot is used to help humans. This can be achieved by introducing a teleoperated robotic arm in which a human can teach the robot before performing tasks remotely. This paper develops and establishes a three-degree-of-freedom robotic arm and teaching pendant. In particular, a flexible robotic arm is operated in two different modes, namely, the teleoperated mode and the semi-autonomous mode. The teleoperated mode is a manual control using a teaching pendant, where the robot arm replicates various movements of the teaching pendant. On the contrary, the semi-autonomous mode allows the robot to execute a task from one point to another point repetitively after at least one training of the teaching pendant. The Arduino Uno board is employed as a microcontroller, and the integrated development environment ( IDE ) software is used to write and upload the computer code. A series of tests in which the robot performs different tasks is recorded to evaluate the accuracy and consistency of the semi-autonomous and teleoperated modes. The results show that the performance of the proposed low-cost teleoperated robotic arm is reliable and safe to perform various tasks based on the teaching pendant.
Uncertainty and sensitivity analysis applied on commercial tariff with off-peak tariff rider: a case study
Mohammad Nizam Ibrahim;
Anuar Mohamad;
Zainol Asri Abdul Sani @ Salleh;
Mohd Muzafa Jumidali;
Azahar Taib
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1176-1184
Commercial Tariff with Off-Peak Tariff Rider (C1 OPTR) is one type of time-based electricity tariff. The C1 OPTR charges electricity consumers with different electricity rates instead of a flat rate tariff. This paper investigates the C1 OPTR tariff adopted recently by Universiti Teknologi MARA Cawangan Pulau Pinang (UiTMCPP) from its previous flat rate tariff. The investigation involves applying the uncertainty and sensitivity analysis to the average load factor (ALF) model of the UiTMCPP. The ALF model consists of two major factors, namely kilowatt-hour (kWh) and maximum demand (kW). The analysis aims to identify the most contributing factor between the kWh and kW to the uncertainty of the ALF in a systematic way using Monte Carlo simulation. The factor identified is important for improvement by UiTMCPP to ensure that the suitable target ALF can be easily achieved. Based on Sobol uncertainty and sensitivity analysis technique, 60,000 samples for the respective kWh and kW have been generated and executed to produce the output of the ALF model. The result of the uncertainty analysis shows that the ALF output is uncertain between 0.195 and 0.343. Furthermore, the applied sensitivity analysis discovers that the kW is the most contributing factor to the ALF output uncertainty, with the sensitivity index indicating 0.8853.
Synthesis and photoluminescence properties in white light-emitting diodes of oxynitride green phosphor Ba3Si6O12N2
Dieu An Nguyen Thi;
Phan Xuan Le
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1264-1269
Utilizing boron-coated Eu2O3, highly effective Ba3Si6O12N2 green-emitting phosphors were made using a gas reduction nitridation technique under flowing NH3 gas. We found that the synthesized phosphor is a pure phase of Ba3Si6O12N2 based on X-ray diffraction patterns. By modifying an alumina boat crystallized, the Ba3Si6O12N2 green-emitting phosphors from the result were considerably better and had higher emission intensity. Under stimulation at 405 nm, the radiation spectra revealed a typical wide green radiation band attributable to the 4f65d → 4f7 electronic transfer of Eu2+ ions. Generally, the green-emitting Ba3Si6O12N2 phosphors that were created by that method with boron-coated Eu2O3 is a potential phosphor-transformed diodes which emit white illumination white light emitting diodes(pc-WLEDs') element.
Alzheimer’s disease prediction using three machine learning methods
Shaymaa Taha Ahmed;
Suhad Malallah Kadhem
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1689-1697
Alzheimer's disease (AD) is the most common incurable neurodegenerative illness, a term that encompasses memory loss as well as other cognitive abilities. The purpose of the study is using precise early-stage gene expression data from blood generated from a clinical Alzheimer's dataset, the goal was to construct a classification model that might predict the early stages of Alzheimer's disease. Using information gain (IG), a selection of characteristics was chosen to provide substantial information for distinguishing between normal control (NC) and early-stage AD participants. The data was divided into various sizes; three distinct machine learning (ML) algorithms were used to generate the classification models: support vector machine (SVM), Naïve Bayes (NB), and k-nearest neighbors (K-NN). Using the WEKA software tool and a variety of model performance measures, the capacity of the algorithms to effectively predict cognitive impairment status was compared and tested. The current findings reveal that an SVM-based classification model can accurately differentiate cognitively impaired Alzheimer's patients from normal healthy people with 96.6% accuracy. As discovered and validated a gene expression pattern in the blood that accurately distinguishes Alzheimer's patients and cognitively healthy controls, demonstrating that changes specific to AD can be detected far from the disease's core site.
Remote laser welding simulation for aluminium alloy manufacturing using computational fluid dynamics model
Raghad Ahmed Al-Aloosi;
Zainab Abdul-Kareem Farhan;
Ahmad H. Sabry
Indonesian Journal of Electrical Engineering and Computer Science Vol 27, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science
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DOI: 10.11591/ijeecs.v27.i3.pp1533-1541
The process of remote laser welding is simulated in this study to identify the keyhole-induced porosity generation mechanisms and keyhole. Three processes are simulated and discussed: laser power levels, laser-beam shaping configurations, and laser keyhole process. The simulation finding reveals that pore development is caused by strong melt flow behind the keyhole. As verification, the equivalent experimental test is also carried out. According to the findings, a welding speed with a high level helps to keep the keyholes released and prevents the flow of strong melt; a big advanced leaning-angle also provides inactive molten pool flow, making it difficult for bubbles to float to the backside of the molten pool. The conclusions of this study offer crucial insight into the method of porosity of aluminum (Al) alloys laser welding, as well as advice on how to avoid keyhole-induced porosity. It is also obtained that a smaller laser beam with constant power raises the velocity, welding pool depth, and liquid metal temperature.