Azura Che soh

Dr. Azura Che soh

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 March 2021 in Micromachines
Verified
Journal Article
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Sarmad Nozad MahmoodSarmad Nozad Mahmood
Sarmad Nozad Mahmood
AIAsnor Juraiza Ishak
Asnor Juraiza Ishak
TSTale Saeidi
Tale Saeidi
ASAzura Che soh
Azura Che soh
Ali Sadeq JalalAli Sadeq Jalal
Ali Sadeq Jalal
Qammer AbbasiQammer Abbasi
Qammer Abbasi
Wireless body area network (WBAN) applications have broad utility in monitoring patient health and transmitting the data wirelessly. WBAN can greatly benefit from wearable antennas. Wearable antennas provide comfort and continuity of the monitoring of the patient. Therefore, they must be comfortable, flexible, and operate without excessive degradation near the body. Most wearable antennas use a truncated ground, which increases specific absorption rate (SAR) undesirably. A full ground ultra-wideband (UWB) antenna is proposed and utilized here to attain a broad bandwidth while keeping SAR in the acceptable range based on both 1 g and 10 g standards. It is designed on a denim substrate with a dielectric constant of 1.4 and thickness of 0.7 mm alongside the ShieldIt conductive textile. The antenna is fed using a ground coplanar waveguide (GCPW) through a substrate-integrated waveguide (SIW) transition. This transition creates a perfect match while reducing SAR. In addition, the proposed antenna has a bandwidth (BW) of 7–28 GHz, maximum directive gain of 10.5 dBi and maximum radiation efficiency of 96%, with small dimensions of 60 × 50 × 0.7 mm3. The good antenna’s performance while it is placed on the breast shows that it is a good candidate for both breast cancer imaging and WBAN.

20 October 2021 in Electronics
Verified
Journal Article
Open access
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Sarmad Nozad MahmoodSarmad Nozad Mahmood
Sarmad Nozad Mahmood
AIAsnor Juraiza Ishak
Asnor Juraiza Ishak
Ali Sadeq JalalAli Sadeq Jalal
Ali Sadeq Jalal
TSTale Saeidi
Tale Saeidi
SSSuhaidi Shafie
Suhaidi Shafie
Qammer AbbasiQammer Abbasi
Qammer Abbasi
This paper represents a miniaturized, dual-polarized, multiple input–multiple output (MIMO) wearable antenna. A vertically polarized, leaf-shaped antenna and a horizontally polarized, tree-shaped antenna are designed, and the performance of each antenna is investigated. After designing the MIMO antenna, it is loaded with stubs, parasitic spiral, and shorting pins to reduce the coupling effects and remove the unwanted resonances. Afterward, the two-port MIMO cells are spaced by 2 mm and rotated by 90° to create three more cells. The antennas are designed using two layers of denim and felt substrates with dielectric constants of 1.2 and 1.8, and thicknesses of 0.5 mm and 0.9 mm, respectively, along with the ShieldIt™ conductive textile. The antenna covers a bandwidth of 4.8–30 GHz when the specific absorption rate (SAR) meets the 1 g and 10 g standards. Isolation greater than 18 dB was obtained and mutual coupling was reduced after integrating shorting pins and spiral parasitic loadings. A maximum radiation efficiency and directive gain of 96% and 5.72 dBi were obtained, respectively, with the relatively small size of 11 × 11 × 1.4 mm3 for the single element and final dimensions of 24 × 24 × 1.4 mm3 for the full assembly. The antenna’s performance was examined for both on-body (breast) and free space conditions using near-field microwave imaging. The achieved results such as high fidelity, low SAR, and accuracy in localization of the tumour indicate that the MIMO antenna is a decent candidate for breast cancer imaging.

18 March 2024 in IEEE Access
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Journal Article
Open access
BASHAR ABBAS FADHEELBASHAR ABBAS FADHEEL
BASHAR ABBAS FADHEEL
NOOR IZZRI ABDUL WAHABNOOR IZZRI ABDUL WAHAB
NOOR IZZRI ABDUL WAHAB
Premkumar MPremkumar M
Premkumar M
Ali Jafer MahdiAli Jafer Mahdi
Ali Jafer Mahdi
MRMohd Amran Mohd Radzi
Mohd Amran Mohd Radzi
BABizuwork Derebew Alemu
Bizuwork Derebew Alemu
This paper introduces a robust approach, integrating a Virtual Inertia Controller (VIC) with a modified demand response controller for an islanded Multi-Microgrid (MMG) system, accommodating high levels of Renewable Energy Sources (RESs). In these MGs, the low inertia in the system has an undesirable impact on the stability of MG frequency. As a result, it leads to a weakening of the MGs overall performance. A novel fractional derivative virtual inertia is integrated into the VIC loop to address this issue. This enhancement aims to fortify the MG’s stability and robust performance, particularly when facing contingencies. Furthermore, a modified demand response controller has been incorporated into the proposed inertia control technique to mitigate the frequency fluctuations and reduce stress on the energy storage system (ESS). Fractional Order Proportional Integral Derivative (FOPID) controllers have been employed to regulate the active power output of the biodiesel generators and the Geothermal station in the MG. The hybrid sparrow search and mountain gazelle optimizer algorithm (SSAMGO) optimizes the parameters for the three-loop controller. Time-domain simulations assess the effectiveness of proposed controllers in enhancing system frequency stability. SSAMGO’s performance was comprehensively evaluated, comparing it to various optimization algorithms in diverse scenarios. The results obtained from the MMG system demonstrate that utilizing the proposed controller technique, optimized with hybrid SSAMGO parameters, yields notable improvements in settling time by 24.68%, 46.20%, 7.52%, and 61.01%, steady-state error values by 72.56%, 98.18%, 98.73%, and 6.67%, undershoot by 105.76%, 144.23%, 19.23%, and 7.69% compared to other state-of-the-art algorithms presented in the literature. Finally, the proposed control technique’s effectiveness and robustness are assessed in comparison to conventional inertia control across various system scenarios. These scenarios encompass random load demand fluctuations, real-time changes in RES, and a wide spectrum of system operations, including situations with reduced damping and inertia and high levels of load variation.

4 May 2018 in Energies
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Journal Article
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Muhammad Ammirrul  Atiqi Mohd ZainuriMuhammad Ammirrul Atiqi Mohd Zainuri
Muhammad Ammirrul Atiqi Mohd Zainuri
MRMohd Amran Mohd Radzi
Mohd Amran Mohd Radzi
ASAzura Che soh
Azura Che soh
NMNorman Mariun
Norman Mariun
NRNasrudin Abd Rahim
Nasrudin Abd Rahim
Ching-Ming LaiChing-Ming Lai
Ching-Ming Lai
This manuscript presents a significant work in improving the current harmonics extraction algorithm and indirectly improving the injection current produced by a single-phase Photovoltaic Shunt Active Power Filter (PV SAPF). Improvement to the existing adaptive linear neuron (ADALINE) technique has been carried out, leading to the formation of a simpler ADALINE; it is expected to perform as fast as the current harmonics extraction algorithm. Further analysis on the DC link capacitor control algorithm, called “self-charging with step size error cancellation”, was also done to inspect the performance of the algorithm in a single-phase photovoltaic shunt active power filter system. Both algorithms, configured in single-phase PV SAPF, were simulated in MATLAB/Simulink (R2012b). A laboratory prototype was developed, and the algorithms were computed on a TMS320F28335 Digital Signal Processing (DSP) board for hardware implementation purposes. From the acquired results, the simpler ADALINE algorithm has effectively performed with lower total harmonic Distortion (THD) and outstanding compensation. The established algorithm of self-charging with step size error cancellation works well with single-phase PV SAPF and has shown less overshoot, a fast response time, and minimal energy losses.

20 January 2023 in Energies
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BASHAR ABBAS FADHEELBASHAR ABBAS FADHEEL
BASHAR ABBAS FADHEEL
NOOR IZZRI ABDUL WAHABNOOR IZZRI ABDUL WAHAB
NOOR IZZRI ABDUL WAHAB
Ali Jafer MahdiAli Jafer Mahdi
Ali Jafer Mahdi
Premkumar MPremkumar M
Premkumar M
MRMohd Amran Mohd Radzi
Mohd Amran Mohd Radzi
AIAndrew Xavier Raj Irudayaraj
Andrew Xavier Raj Irudayaraj
Nowadays, renewable energy (RE) sources are heavily integrated into the power system due to the deregulation of the energy market along with environmental and economic benefits. The intermittent nature of RE and the stochastic behavior of loads create frequency aberrations in interconnected hybrid power systems (HPS). This paper attempts to develop an optimization technique to tune the controller optimally to regulate frequency. A hybrid Sparrow Search Algorithm-Grey Wolf Optimizer (SSAGWO) is proposed to optimize the gain values of the proportional integral derivative controller. The proposed algorithm helps to improve the original algorithms’ exploration and exploitation. The optimization technique is coded in MATLAB and applied for frequency regulation of a two-area HPS developed in Simulink. The efficacy of the proffered hybrid SSAGWO is first assessed on standard benchmark functions and then applied to the frequency control of the HPS model. The results obtained from the multi-area multi-source HPS demonstrate that the proposed hybrid SSAGWO optimized PID controller performs significantly by 53%, 60%, 20%, and 70% in terms of settling time, peak undershoot, control effort, and steady-state error values, respectively, than other state-of-the-art algorithms presented in the literature. The robustness of the proffered method is also evaluated under the random varying load, variation of HPS system parameters, and weather intermittency of RE resources in real-time conditions. Furthermore, the controller’s efficacy was also demonstrated by performing a sensitivity analysis of the proposed system with variations of 75% and 125% in the inertia constant and system loading, respectively, from the nominal values. The results show that the proposed technique damped out the transient oscillations with minimum settling time. Moreover, the stability of the system is analyzed in the frequency domain using Bode analysis.

27 May 2016 in Energies
Verified
Journal Article
Open access
PDF file
Muhammad Ammirrul  Atiqi Mohd ZainuriMuhammad Ammirrul Atiqi Mohd Zainuri
Muhammad Ammirrul Atiqi Mohd Zainuri
MRMohd Amran Mohd Radzi
Mohd Amran Mohd Radzi
ASAzura Che soh
Azura Che soh
NMNorman Mariun
Norman Mariun
NRNasrudin Abd Rahim
Nasrudin Abd Rahim
SHShahrooz Hajighorbani
Shahrooz Hajighorbani
This paper presents improvement of a harmonics extraction algorithm, known as the fundamental active current (FAC) adaptive linear element (ADALINE) neural network with the integration of photovoltaic (PV) to shunt active power filters (SAPFs) as active current source. Active PV injection in SAPFs should reduce dependency on grid supply current to supply the system. In addition, with a better and faster harmonics extraction algorithm, the SAPF should perform well, especially under dynamic PV and load conditions. The role of the actual injection current from SAPF after connecting PVs will be evaluated, and the better effect of using FAC ADALINE will be confirmed. The proposed SAPF was simulated and evaluated in MATLAB/Simulink first. Then, an experimental laboratory prototype was also developed to be tested with a PV simulator (CHROMA 62100H-600S), and the algorithm was implemented using a TMS320F28335 Digital Signal Processor (DSP). From simulation and experimental results, significant improvements in terms of total harmonic distortion (THD), time response and reduction of source power from grid have successfully been verified and achieved.