kein huat chua | Universiti Tunku Abdul Rahman (original) (raw)

Papers by kein huat chua

IEEE Access

The use of Convolutional Neural Networks (CNN) for the application of wood defects detection has ... more The use of Convolutional Neural Networks (CNN) for the application of wood defects detection has gained significant attention in recent years. In industrial settings, these tasks are typically performed in a strict and consistent environment, making the use of large and complex CNN models unnecessary. Despite this, recent research has continued to focus on the use of such models to achieve increasingly accurate detections. These models require costly machines for inference, making adoption less likely especially for manufacturers in the developing nations. In view of this limitation, this paper proposes a set of strategies to achieve a highly efficient CNN model for fast and accurate wood defects detection based on the YOLOv4-Tiny architecture. The model has been improved with Efficient Channel Attention (ECA) to better select multi-scale features from the backbone network and has been drastically reduced in size through an iterative pruning and recovery process. This results in an 88% reduction in model parameters while retaining accuracy comparable to most state-of-the-art (SOTA) methods. Consequently, the model can perform near real-time inference directly on a general-purpose embedded processor without external hardware accelerators. This research hopes to motivate the development of efficient defect detectors that can run on low-cost embedded devices.

2022 IEEE Industry Applications Society Annual Meeting (IAS)

IOP Conference Series: Earth and Environmental Science

Battery-based energy storage has emerged as a cost-effective solution for peak reduction due to t... more Battery-based energy storage has emerged as a cost-effective solution for peak reduction due to the decrement of battery's price. In this study, a battery-based energy storage system is developed and implemented to achieve an optimal peak reduction for commercial customers with the limited energy capacity of the energy storage. The energy storage system is formed by three bi-directional power converter rated at 5 kVA and a battery bank with capacity of 64 kWh. Three control algorithms, namely fixed-threshold, adaptive-threshold, and fuzzybased control algorithms have been developed and implemented into the energy storage system in a campus building. The control algorithms are evaluated and compared under different load conditions. The overall experimental results show that the fuzzy-based controller is the most effective algorithm among the three controllers in peak reduction. The fuzzy-based control algorithm is capable of incorporating a priori qualitative knowledge and expertise about the load characteristic of the buildings as well as the useable energy without over-discharging the batteries.

2022 IEEE International Conference in Power Engineering Application (ICPEA)

Electric locomotives can reduce traffic congestion and carbon footprints, especially those with r... more Electric locomotives can reduce traffic congestion and carbon footprints, especially those with regenerative braking energy (RBE) recovery. However, the amount of regenerated energy is affected by the aerodynamics of the running train. This paper aims to investigate the effects of the aerodynamics of running trains on RBE. A railway power supply and distribution networks for MRT Line 2 in Malaysia are modeled using ETAP - eTraX software. The rolling stocks parameters are obtained from the manufacturer's datasheet. The running resistance of the train in the open-air and tunnel are derived and modeled based on the developer's parameters. The results show that the energy consumptions of the train moved in the tunnel is 2.15 times higher than that of open-air for the case with RBE. Besides, the RBE obtained from the train moved in the open-air is 2.5 times higher than that of the train moved in the tunnel.

2021 IEEE Industry Applications Society Annual Meeting (IAS)

This paper presents the damping-improvement outcomes of a large-scale offshore wind farm (OWF) ba... more This paper presents the damping-improvement outcomes of a large-scale offshore wind farm (OWF) based on doubly-fed induction generator (DFIG) fed to a two-area four-generator power system using a generalized unified power-flow controller (GUPFC). Two proportional-integral-derivative (PID) damping controllers and two fuzzy logic controllers (FLCs) of the proposed GUPFC are designed to improve the damping of the dominant modes of the studied multi-machine power system under different operating conditions, respectively. Eigenvalue analysis and nonlinear-model simulations are both performed to examine the effectiveness of the proposed GUPFC equipped with the designed damping controllers. The comparative simulation results show that the proposed GUPFC joined with the designed FLCs demonstrates better damping performance for improving the damping of the dominant modes of the studied multimachine system subject to different disturbances than the designed PID damping controllers.

2019 1st International Conference on Electrical, Control and Instrumentation Engineering (ICECIE), 2019

A reputable Surge Protection Device (SPD) manufacturer designed, tested and produced SPD complyin... more A reputable Surge Protection Device (SPD) manufacturer designed, tested and produced SPD complying with the internationally accepted standard such as UL 96A, UL1449, IEC 61643, IEC 62305 and etc., where this standard put in place the requirement on the thermal disconnect to prevent SPD from overheated catching fire, housing material from releasing toxic gases and so on. Therefore, when an SPD which carried international approval, the selection is mainly focused on the let-through voltage, kA rating and protection class or zone per ANSI/IEEE C62.4 and IEC 62305–4. This is sufficient when the application is for a safe area (no present of explosive gases). However, when the application involves the presence of explosive gas in a hazardous area, for example, in the Oil and Gas industry, additional consideration will be required. This paper discussed the application and consideration of SPD for hazardous areas with various explosion protection techniques.

Received Mar 17, 2021 Revised May 27, 2021 Accepted Jun 10, 2021 Nonintrusive load monitoring (NI... more Received Mar 17, 2021 Revised May 27, 2021 Accepted Jun 10, 2021 Nonintrusive load monitoring (NILM) based energy efficiency can conserve electricity by creating awareness with the behaviour change and shrinking CO2 emissions to the environment. However, the lack of effective models and strategies is problematic for policymakers to forecast quantitatively CO2 emissions. This paper aims to study the impact of NILM on CO2 emissions in Malaysia. Firstly, the predictive models were established based on Malaysia open data from 1996 to 2018. After that, scenario simulations were conducted to predict CO2 emissions and NILM impact on environmental degradation in 2019-2030. The results revealed that a 12% reduction in electricity consumption due to NILM could contribute to a 10.2% shrinkage of the total CO2 emissions. The result also statistically confirmed Malaysia to achieve a 45% reduction of CO2 intensity in 2030. With NILM, the carbon reduction can be further enhanced to 60.2%. The outc...

Journal of Electronic Science and Technology, 2017

This paper outlines the barriers and potential benefits of using standby diesel generators in mit... more This paper outlines the barriers and potential benefits of using standby diesel generators in mitigating the peak demands for commercial and industrial customers. The feasibility of utilizing the standby diesel generators to reduce the electricity bills for customers is carried out by using the hybrid optimization model for electric renewable (HOMER) software. The size of the standby diesel generator and its operational duration are determined based on the lowest cost of electricity obtained from the evaluations. The economic assessments demonstrate that there is potential to reduce the electricity bills for commercial and industrial customers under the existing fuel price and tariffs. The commercial customers under the tariff C2 have the highest potential to save their electricity bills with the use of standby diesel generators for peak reduction. This study demonstrates the potential of the standby diesel generators in peak reduction.

Journal of Electronics and Advanced Electrical Engineering, 2021

Harmonic distortion is one of the most important power quality issues in third rail electrificati... more Harmonic distortion is one of the most important power quality issues in third rail electrification systems. The use of rectifiers and inverters in the third rail system can inject a significant amount of harmonic distortion to the electrical network. This paper aims to investigate the harmonic distortions for a DC urban third rail system at various operating conditions. The electrical network of Mass Rapid Transit Line 2 (MRT 2) Malaysia is modelled using ETAP software. The model had considered the effect of the inter-phase transformer in the 12-pulse rectifier. The current injection method is used to measure harmonic distortion at Point of Common Coupling (PCC) at the 132 kV and 33 kV buses. A normal and degraded operating conditions of power supply are investigated. From the simulation results, it is found that the 11th and 13th order harmonics have exceeded the statutory limit at 33 kV network for the normal operating condition. For the degraded operating condition, only the 11t...

International Journal of Electrical and Electronic Engineering & Telecommunications., 2018

 Isolated areas are usually located a distance away from the main power grids where supplies of ... more  Isolated areas are usually located a distance away from the main power grids where supplies of electricity rely on diesel generators. Although the initial investment cost of diesel generators is usually low, the fuel cost can be very high over a period of time. Consequently, renewable energy sources such as photovoltaic systems (PV) and micro-hydro generators are used in conjunction with diesel generators to reduce fuel costs. However, poor management and coordination of the energy sources may not solve the issue of high fuel consumption. In order to address this effectively, an innovative energy storage system has been developed to coordinate with various energy sources to reduce the fuel consumption to a minimum. The energy storage system is controlled by a fuzzy controller, which is able to extend the shutdown period of diesel generators and hence minimize fuel consumption. The performance of the energy storage system, as verified in MATLAB/Simulink, indicates that the fuel consumption is reduced by 8%.

Journal of Energy Engineering, 2017

AbstractCommercial and industrial customers are subject to monthly maximum demand charges, which ... more AbstractCommercial and industrial customers are subject to monthly maximum demand charges, which can be as high as 30% of the total electricity bill. A battery-based energy storage system (BESS) ca...

2010 IEEE International Conference on Power and Energy, 2010

Abstract This paper presents an improved performance of a Permanent Magnet Synchronous Motor (PMS... more Abstract This paper presents an improved performance of a Permanent Magnet Synchronous Motor (PMSM) using a hybrid Fuzzy/Proportional-Integral (PI) controller. Hybrid control has an advantage of integrating a superiority of two or more control ...

Energy, 2017

Commercial and industrial customers are subject to the monthly maximum demand charges which can b... more Commercial and industrial customers are subject to the monthly maximum demand charges which can be as high as 30% of the total electricity bills. Battery-based energy storage system (BESS) can be used to reduce the monthly maximum demand charges. A number of control strategies have been developed for the BESS to reduce the daily peak demands. A fuzzy control algorithm is developed to reduce the daily peak demands with the limited capacity of the BESS. Its performance is evaluated at two different buildings, namely building A and B. The fuzzy controller forecasts the load profile one day in advance using the historical load data. Then during the day of peak reduction, the controller will adjust the power output of BESS using the latest state of charge and operation time. The performance of the fuzzy controller is compared with other two controllers developed in the past. The experimental results show that fuzzy controller is the most effective approach for the peak reduction under the limited capacity of the BESS.

International Journal of Power Electronics and Drive Systems (IJPEDS)

The proposed scheme is employed for the efficient operation of a DC-DC-based buck converter. This... more The proposed scheme is employed for the efficient operation of a DC-DC-based buck converter. This protection scheme shows the optimal placement of a varistor in the power electronics converter side under different surge conditions. Advanced varistors have excellent electrical material properties and electrothermal behavior for the enhancement of power absorption capability. Varistors have been examined widely in the last four decades that are employed for surge protection applications. The advantage of power surge protection using varistor-based power devices is vital due to the great sensitivity of the equipment integrated into the grid and emerging power electronics-based DC systems with low and high voltage ratings. In this research, a varistor can be placed to protect the switching devices such as MOSFETs in power electronic-based buck converter side due to uncertain overvoltage under differential surge. The proposed MATLAB simulation study shows the peak voltage stress on the g...

2022 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS)