azli yahya
@my.utm.my
Dr Electrical Engineering
universiti teknologi malaysia
Azli Yahya is an Associate Professor at Universiti Teknologi Malaysia since 2015. He is also a Chartered (CEng) and Professional Engineer (PEng). He holds a Degree in Electro -Mechanical Power System and Masters Degree in Electronic Production from Glamorgan University, UK. He is a doctorate of Loughborough University, UK specializing in Power Electronic System. His areas of researches are Analog/Digital Circuit Design, Power Supply, Electrical Discharge Machining and Biomedical Instrumentation. He has authored or co -authored more than 100 papers published in international/national journals and conferences. At national level, he serves SIRIM as technical committees for Active Medical Devices And Low-Voltage Equipment/System For Healthcare Facilities (SIRIM TC10) and Anaesthetic/Respiratory and Electromechanical Devices (SIRIM TC3)
EDUCATION
PhD in Electrical Engineering
RESEARCH, TEACHING, or OTHER INTERESTS
Electrical and Electronic Engineering, Biomedical Engineering, Industrial and Manufacturing Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Betantya Nugroho, Azli Yahya, Nor Hisham H. Khamis, Abd Rahim Mat Sidek, Raimi Dewan, Trias Andromeda, and Kartiko Nugroho
AIP Publishing
Yahaya Hassan, Azli Yahya, Norhalimah Idris, and Luqman Hafiz Elias
AIP Publishing
M. Harun, M. Z. Ramli, M. A. A. Ahmad, M. Mohd Mokji, A. Yahya, S. Z. Abdul Hamid, and J. Kasim
AIP Publishing
Septianissa Azzahra, Azli Bin Yahya, Eko Supriyanto, Samsurizal, Zainal Arifin, and Yana Agustianingsih
IEEE
A solar thermal-to-electricity conversion system that optimizes the temperature difference between hot and cold sources has been designed using Peltier thermoelectric. The system consists of three main components, namely the heating system, cooler, and drive to position the prototype following the direction of motion of the sun. With a greenhouse effect concept, the heating system at the top keeps the temperature in the acrylic room warm. The hot side of the Peltier is placed with an aluminum plate and andesite stone as heat conductors and storage. The cooling system uses a metal-wrapped fluid as a source of cold temperature equipped with temperature-reducing aluminum foil and nitrogen gas to keep the fluid at a low temperature. Finally, the drive system uses a hydraulic to move the design module following the direction of motion of the sun, whose light will be focused by a convex lens to concentrate. The Peltier is assembled in series and step-up to increase the output voltage to produce maximum results. This prototype design can hopefully contribute to the development of renewable energy.
Sasikala Devi Thangavelu, Eko Supriyanto, Azli Yahya, Mohamad Haider Abu Yazid, Shaman Kalearasu, and Aishriah Kalearasu
IEEE
In high workload areas such as the Intensive or Critical Care Units (ICU/CCU), clinicians are burdened with too many alarms and false alarms, leading to poor user response or no response to alarm signals, which in turn leads to serious patient safety concerns, adverse events such as injury and deaths. Even with the implementation of the IEC international alarm standard, alarm hazards are still seen as the top health technology hazard in healthcare institutions. There are numerous new developments in alarm technology, including in the areas of alarm detection and smart alarm design, aimed at improving the sensitivity and performance of alarm systems. However, there is still a lack of studies on the application of Human Factors Engineering (HFE) principles and AI in designing alarms for medical devices that could improve user response and ensure patient safety. This research aims to develop a fuzzy logic base multimodality clinical alarm monitor software to improve alarm response among the clinicians in ICU/CCU and the performance of the clinical alarm. The research involves testing, verifying, and validating the fuzzy-based multimodality clinical alarm to improve the performance of the alarm system. The proposed fuzzy alarm is compared to the medical professional interpretation of a patient physiological condition extracted from the MIMIC II database. The results show that the proposed fuzzy alarm can match the interpretation of medical professionals with high accuracy. In terms of sensitivity and specificity, the proposed alarms achieve good performance with blood pressure and heart rate specificity and sensitivity at 100%. Meanwhile, sensitivity and specificity for respiratory rate are at 97.59% and 99.68%, while sensitivity and specificity for oxygen saturation are at 100% and 98.04%, respectively. The research concluded that incorporating alarm information systems based on risk, human factor engineering principles, and fuzzy logic into the alarm system significantly improves user response while reducing alarm hazards and optimising the performance of the alarm system.
Thompson Paulus, Nur Amira Zulkiflli, Fatin Aliah Phang Abdullah, Azli Yahya, Siti Zarina Abdul Muji, and Jaysuman Pusppanathan
Penerbit UTM Press
Nephrolithiasis is a process of stone formation in the kidney by crystallization. The increasing prevalence of nephrolithiasis from time to time had sought an alternative from the conventional imaging techniques that is invasive, radiative, and non-rapid usage. This paper enclosed a design simulation study of Magnetic Induction Tomography (MIT) system using COMSOL Multiphysics for renal imaging. MIT is a soft field tomography and non-contact imaging modality which can project the passive electromagnetic properties (conductivity, permittivity and permeability) under the principle of electromagnetic induction. In this research also, 8 copper trans-receiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ was set to imitate the transverse section of human renal. In the methodology, sensor performance analyses were done using frequency ranging from 50 kHz to 2 MHz of the MIT system on radii of calcium oxalate in renal. The sensor response and pattern is discussed in this paper.
Jahanzeb Sheikh, Tan Tian Swee, Syafiqah Saidin, Azli Bin Yahya, Sameen Ahmed Malik, Joyce Sia Sin Yin, and Matthias Tiong Foh Thye
Springer Science and Business Media LLC
Joyce Sin Yin Sia, Tian Swee Tan, Azli Bin Yahya, Matthias Foh Thye Tiong, and Jeremy Yik Xian Sia
IAES Indonesia Section
Maisarah Sulaiman, Aizreena Azaman, Noor Aimie Salleh, and Azli Yahya
Springer International Publishing
Husnir Nasyuha Abdul Halim, Aizreena Azaman, and Azli Yahya
Springer International Publishing
B Nugroho, A Yahya, A R Mat Sidek, T Andromeda, and N H Khamis
IOP Publishing
Electrical Discharge Machining (EDM) is a process that uses electrical discharges to erode electrically conductive material where the electrode and workpiece do not touch. Spark between electrode and workpiece in the EDM process produced magnetic fields. The magnetic fields is found to have an effect on debris circulation in the gap of EDM, so it can decrease the abnormal electrical discharge. An electric current has an effect on the magnetic field produced. EDM uses the RC-generator configuration, so it is able to produce greater currents. This paper presents the calculation current pulse generated by spark of EDM. This calculation can be used to predict peak currents from EDM pulses. Predict peak current is used to find out the maximum magnetic field and determine the maximum current rating of a component. Pulse current calculation can use the equation that has been stated.
Ali Idham Abdullah, Azli yahya, Mohammad Rava, Tan Tin Swee, and Norhalimah Idris
IOP Publishing
Abstract Electrosurgery has been regarding as one of the top forms of surgical interventions. This technology allows surgical procedures to be performed with high accuracy using high-frequency energy waves in order to cut organic tissue. Although there are a lot of benefits to this form of surgery, there are also dangers that originate due to the thermal nature of the procedure. Some of these issues relate to the thermal damge that can be caused by the ESU. Thus, in order to address this issue, this research proposes to use thermal sensors that can sense and read temperature fluctuations, and then by manipulating the ESG, to control the thermal output and ultimately prevent any thermal adamage to the tissue. An experiment is performed using chicken as the main tissue and experimenting with and without the controller. The results of the experiment indicated success, and that the proposed thermal control system can regulate the power and the temperature with the use of the thermal monitoring systems it has in place. The damage observed on the tissue has been observed to be little to none.
M A C Abdullah, A Yahya, and W N W M Shukri
IOP Publishing
Abstract Electrical discharge machining (EDM) is one of the earliest non-conventional machining in order to manufacture very accurate 3-D complex components on any electrically conductive materials. In die-sinking EDM, a pulse discharge occurs in a small spark gap between electrically conductive workpiece and electrode in dielectric medium. This paper proposed a new integrated control system using Programmable System-on-Chip (PSoC) for Die-sinking EDM in order to enhance Material Removal Rate (MRR). The MRR result of EDM-PSoC system is higher than EDM-Ben Fleming system due to the effect off high speed processing data analysis using PID algorithm in PSoC microcontroller and leads to improving system efficiency 41%.
Fandi Hamid, Azli Yahya, Tian Swee Tan, and Kok Yeow You
IOP Publishing
Abstract Modern vehicle architectures are complemented by the use of advanced technologies, primarily in the Engine Control Unit (ECU). This article describes the proposed conceptual design of Electromagnetic Pulse (EMP) for denied vehicular access applications, especially to vehicle (cars) engine ECU. The system mainly consists of five parts, namely power supply, magnetron, isolator, tuner, and pyramidal horn radiator. The magnetron is selected as the means for driving the pulse power generator at an operating frequency of 2.4 GHz. The pyramidal horn radiator with a gain of 15 dB is designed using CST Microwave software and fabricated as well as tested. The performance tests of the designed system are conducted in a laboratory environment and field trials, respectively. The effects of the EMP to the engine ECU are analyzed and discussed in terms of the radiated power, radiation gain, radiation pattern, and significant radiation distance. The expected target distance for stopping a vehicle is at least 3m to 5m.
D Dehghani, A Yahya, and N H Khamis
IOP Publishing
Abstract Electrical discharge machining (EDM) is a non-conventional manufacturing process used broadly in medical applications, aerospace industry and manufacturing in hard material fields. However, information about the process is still in an unfledged stage and it has been becoming a serious obstacle to its more improvements. In this paper, spark discharge condition is studied based on the simulated model of EDM spark pulse generator system equivalent form. Simulated model is verified by comparing with a series of experimental results. Frequency response is established through simplified model of EDM system. Influence of discharge time and stable discharge current on material removal rate (MRR) and stability of the system is analysed. This study is important to select the process parameters, and uses as a guidance to design the EDM spark pulse generator system.
Nor Liyana Safura Hashim, Azli Yahya, and Mohd Azahar Che Abdullah
IOP Publishing
Abstract Surface texturing is a distinct identical feature of discrete dimples or grooves on a surface. In a biomedical application such as hip implant, it has been proven that these dimples can enhance the tribological properties of journal bearings. Realizing the advantages offered by Electrical Discharge Machining (EDM), it was utilized in this research to machine the dimples for the Metal-on-Metal hip implant application. In this research, three sets of inclined angles of 50°, 70°, and 90° were machined on the S24C mild steel material using EDM with pulse currents of 1A, 2A, and 3A. This research focuses on micro-crack formation along the edge of the surface of the dimple after EDM machining, which is critical in a contact sliding bearing.
D Dehghani, A Yahya, and N H Khamis
IOP Publishing
Abstract Electrical discharge machining (EDM) is a stochastic machining process which widely used to generate dies and molds. However, information about the EDM process is still at the earlier stage which lead to experience many challenges for further developments. Experimental analysis is time consuming as well as a costly procedure, due to the highly stochastic and complex nature of the process. Therefore, process modeling is an alternative to reduce the experimental costs related to the technology. This research proposes method to design a mathematical model of electrical discharge machining (EDM) system. The model will be used to understand the effects of machining parameters into the dynamic behaviour of EDM system based on the sparking phases and pulse power generator.
Muhamad Firdaus Mohd Rafi, Arief Ruhullah A Harris, Tan Tian Swee, Kah Meng Leong, Jia Hou Tan, Kelvin Ling Chia Hiik, Tengku Ahmad Iskandar Tengku Alang, Azli Yahya, Joyce Sia Sin Yin, Matthias Tiong Foh Thye,et al.
Penerbit UTM Press
Severe movement or motor disability diseases such as amyotrophic lateral sclerosis (ALS), cerebral palsy (CB), and muscular dystrophy (MD) are types of diseases which lead to the total of function loss of body parts, usually limbs. Patient with an extreme motor impairment might suffers a locked-in state, resulting in the difficulty to perform any physical movements. These diseases are commonly being treated by a specific rehabilitation procedure with prescribed medication. However, the recovery process is time-consuming through such treatments. To overcome these issues, Brain-Computer Interface system is introduced in which one of its modalities is to translate thought via electroencephalography (EEG) signals by the user and generating desired output directly to an external artificial control device or human augmentation. Here, phase synchronization is implemented to complement the BCI system by analyzing the phase stability between two input signals. The motor imagery-based experiment involved ten healthy subjects aged from 24 to 30 years old with balanced numbers between male and female. Two aforementioned input signals are the respective reference data and the real time data were measured by using phase stability technique by indicating values range from 0 (least stable) to 1 (most stable). Prior to that, feature extraction was utilized by applying continuous wavelet transform (CWT) to quantify significant features on the basis of motor imagery experiment which are right and left imaginations. The technique was able to segregate different classes of motor imagery task based on classification accuracy. This study affirmed the approach’s ability to achieve high accuracy output measurements.
Tan Tian Swee, Kelvin Ling Chia Hiik, Tan Jia Hou, Leong Kah Meng, Mohammed Rafiq Abdul-Kadir, Arief Ruhullah A. Harris, Muhamad Firdaus Mohd Rafi, Leo Bodey, Yii Cheng Tay, Azli Yahya,et al.
Penerbit UTM Press
Lie detection has been studied since a few decades ago, usually for the purpose of producing a scheme to assist in the investigation of identifying the culprit from a list of suspects. Heart Rate Variability (HRV) may be used as a method in lie detection due to its versatility and suitability. However, since its analysis is not instantaneous, a new experiment is described in this paper to overcome the problem. Additionally, a preliminary HRV classification model is designed to further enhance the classification model which is able to distinguish the lie from the truth for up to 80%.
Maisarah Sulaiman, Aizreena Azaman, and Azli Yahya
Springer Singapore
Husnir Nasyuha Abdul Halim, Aizreena Azaman, Haidzir Manaf, Syafiqah Saidin, Izwyn Zulkapri, and Azli Yahya
IOP Publishing
Abstract Gait asymmetry is a type of gait characteristics when there is difference in gait parameters statistically, measured bilaterally between left and right limbs. Gait asymmetry assessment is used to observe changes or deviation in gait due to pathological condition, effect of rehabilitation program or to give insight on effect of gait on stability and fall-risk. The assessments of gait asymmetry could be measured by using spatiotemporal, kinetics, kinematics parameters or by analysis of muscle activity signals obtained from surface electromyography (EMG). However, EMG-based assessment for gait asymmetry is not well explored compared to assessment using other gait parameters. This review aims to compare research designs, methods and procedure of previous studies that utilized EMG for gait asymmetry analysis. Therefore, any research in the future that involved gait asymmetry measurement could take note on and produce more reliable findings.
Betantya Nugroho, Azli Yahya, Abd. Rahim Mat Sidek, Trias Andromeda, and Nor Hisham H Khamis
IEEE
EDM is a process of machining electrically conductive materials by precisely controlled electrical discharge through a small clearance gap that occur between an electrode and a workpiece in the presence of a dielectric fluid. Through EDM process, the material of workpiece are melted and gap distance will increase. In order to maintain a stable spark, the gap must be controlled. This paper presents control spark gap system of EDM using PID controller with voltage and position feedbacks. The results show Time Rise (Tr) of PID control with voltage feedback has a value about 75 seconds and Time Rise (Tr) of PID control with voltage and position feedbacks has a value about 18.6 seconds. The average error of gap distance in PID control with voltage feedback is 55.56 and the average error of gap distance in PID control with voltage and position feedbacks is 48.53. Addition of the position feedback is used to increase the rise time and stabilize distance the electrode and the workpiece.
Kartiko Nugroho Juli Purwanto, Azli Yahya, Nor Hisham Haji Khamis, Nuramirah Mohd Nor, Mohammad Razman Shaari, and Abdul Rahim Mat Sidek
IEEE
Amplitude comparison is the simplest method of Radio Direction Finding (RDF) which utilise several directional antennas and compare the signal strength from each antenna to calculate the Angle of Arrival (AoA). There is some jargons mention that more antennas used in amplitude comparison RDF will improve the RDF accuracy. However, a further analysis and real test is still required to support this argument. Therefore, this paper will verify this specific problem by develop 6 antenna RDF system and 4 antenna RDF system then analyse the real test data. A type of printed circuit board log-periodic dipole array (PCB LPDA) antenna is utilised in this paper for the experiment setup. The real test setup and the data collection is explained in this paper to discuss and verify this argument. After the discussion, it is verified that amplitude comparison with 4 antennas has better accuracy than the similar system with 6 antennas.
Ahlam Al-Dhamari, Rubita Sudirman, Nasrul Humaimi Mahmood, Nor Hisham Khamis, and Azli Yahya
Universitas Ahmad Dahlan
At the essence of video surveillance, there are abnormal detection approaches, which have been proven to be substantially effective in detecting abnormal incidents without prior knowledge about these incidents. Based on the state-of-the-art research, it is evident that there is a trade-off between frame processing time and detection accuracy in abnormal detection approaches. Therefore, the primary challenge is to balance this trade-off suitably by utilizing few, but very descriptive features to fulfill online performance while maintaining a high accuracy rate. In this study, we propose a new framework, which achieves the balancing between detection accuracy and video processing time by employing two efficient motion techniques, specifically, foreground and optical flow energy. Moreover, we use different statistical analysis measures of motion features to get robust inference method to distinguish abnormal behavior incident from normal ones. The performance of this framework has been extensively evaluated in terms of the detection accuracy, the area under the curve (AUC) and frame processing time. Simulation results and comparisons with ten relevant online and non-online frameworks demonstrate that our framework efficiently achieves superior performance to those frameworks, in which it presents high values for he accuracy while attaining simultaneously low values for the processing time.