DSpaceCRIS@UNITENThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://dspace.uniten.edu.my/jspui2019-04-25T19:55:58Z2019-04-25T19:55:58Z50901A computational intelligence scheme for the prediction of the daily peak loadNagi, J.Yap, K.S.Nagi, F.Tiong, S.K.Ahmed, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/50142017-11-14T04:52:28Z2011-01-01T00:00:00ZTitle: A computational intelligence scheme for the prediction of the daily peak load
Authors: Nagi, J.; Yap, K.S.; Nagi, F.; Tiong, S.K.; Ahmed, S.K.
Abstract: Forecasting of future electricity demand is very important for decision making in power system operation and planning. In recent years, due to privatization and deregulation of the power industry, accurate electricity forecasting has become an important research area for efficient electricity production. This paper presents a time series approach for mid-term load forecasting (MTLF) in order to predict the daily peak load for the next month. The proposed method employs a computational intelligence scheme based on the self-organizing map (SOM) and support vector machine (SVM). According to the similarity degree of the time series load data, SOM is used as a clustering tool to cluster the training data into two subsets, using the Kohonen rule. As a novel machine learning technique, the support vector regression (SVR) is used to fit the testing data based on the clustered subsets, for predicting the daily peak load. Our proposed SOM-SVR load forecasting model is evaluated in MATLAB on the electricity load dataset provided by the Eastern Slovakian Electricity Corporation, which was used in the 2001 European Network on Intelligent Technologies (EUNITE) load forecasting competition. Power load data obtained from (i) Tenaga Nasional Berhad (TNB) for peninsular Malaysia and (ii) PJM for the eastern interconnection grid of the United States of America is used to benchmark the performance of our proposed model. Experimental results obtained indicate that our proposed SOM-SVR technique gives significantly good prediction accuracy for MTLF compared to previously researched findings using the EUNITE, Malaysian and PJM electricity load datasets. © 2011 Elsevier B.V. All rights reserved.
2011-01-01T00:00:00ZImproving SVM-based nontechnical loss detection in power utility using the fuzzy inference systemNagi, J.Yap, K.S.Tiong, S.K.Ahmed, S.K.Nagi, F.http://dspace.uniten.edu.my/jspui/handle/123456789/50162017-11-14T06:30:21Z2011-01-01T00:00:00ZTitle: Improving SVM-based nontechnical loss detection in power utility using the fuzzy inference system
Authors: Nagi, J.; Yap, K.S.; Tiong, S.K.; Ahmed, S.K.; Nagi, F.
Abstract: This letter extends previous research work in modeling a nontechnical loss (NTL) framework for the detection of fraud and electricity theft in power distribution utilities. Previous work was carried out by using a support vector machine (SVM)-based NTL detection framework resulting in a detection hitrate of 60%. This letter presents the inclusion of human knowledge and expertise into the SVM-based fraud detection model (FDM) with the introduction of a fuzzy inference system (FIS), in the form of fuzzy if-then rules. The FIS acts as a postprocessing scheme for short-listing customer suspects with higher probabilities of fraud activities. With the implementation of this improved SVM-FIS computational intelligence FDM, Tenaga Nasional Berhad Distribution's detection hitrate has increased from 60% to 72%, thus proving to be cost effective. © 2011 IEEE.
2011-01-01T00:00:00ZNontechnical loss detection for metered customers in power utility using support vector machinesNagi, J.Yap, K.S.Tiong, S.K.Ahmed, S.K.Mohamad, M.http://dspace.uniten.edu.my/jspui/handle/123456789/50262017-11-14T07:17:51Z2010-01-01T00:00:00ZTitle: Nontechnical loss detection for metered customers in power utility using support vector machines
Authors: Nagi, J.; Yap, K.S.; Tiong, S.K.; Ahmed, S.K.; Mohamad, M.
Abstract: Electricity consumer dishonesty is a problem faced by all power utilities. Finding efficient measurements for detecting fraudulent electricity consumption has been an active research area in recent years. This paper presents a new approach towards nontechnical loss (NTL) detection in power utilities using an artificial intelligence based technique, support vector machine (SVM). The main motivation of this study is to assist Tenaga Nasional Berhad (TNB) Sdn. Bhd. in peninsular Malaysia to reduce its NTLs in the distribution sector due to abnormalities and fraud activities, i.e., electricity theft. The fraud detection model (FDM) developed in this research study preselects suspected customers to be inspected onsite fraud based on irregularities in consumption behavior. This approach provides a method of data mining, which involves feature extraction from historical customer consumption data. This SVM based approach uses customer load profile information and additional attributes to expose abnormal behavior that is known to be highly correlated with NTL activities. The result yields customer classes which are used to shortlist potential suspects for onsite inspection based on significant behavior that emerges due to fraud activities. Model testing is performed using historical kWh consumption data for three towns within peninsular Malaysia. Feedback from TNB Distribution (TNBD) Sdn. Bhd. for onsite inspection indicates that the proposed method is more effective compared to the current actions taken by them. With the implementation of this new fraud detection system TNBD's detection hitrate will increase from 3% to 60%. © 2010 IEEE.
2010-01-01T00:00:00ZAnalysis of real-time multiple source video streaming via wireless 5.8 GHz for intelligent traffic management systemBaskaran, V.M.Tiong, S.K.Jamaludin, M.Z.http://dspace.uniten.edu.my/jspui/handle/123456789/66012017-12-08T09:51:59Z2007-01-01T00:00:00ZTitle: Analysis of real-time multiple source video streaming via wireless 5.8 GHz for intelligent traffic management system
Authors: Baskaran, V.M.; Tiong, S.K.; Jamaludin, M.Z.
Abstract: This paper evaluates the performance of live compressed motion image transmission in coherence with the development of the Multiple Video Streaming and Compression (Multiple-VSCS) software, as applied for the Intelligent Traffic Management system. Motion Images of multiple sources are captured, jointly compressed and streamed real time via utilization of the 5.8 GHz OFDM Outdoor Wireless LAN network. Experiments were performed and analyzed to ascertain the reliability and potency of this application with improved bitstream rates as low as 50kbps and compression ratio rates as high as 1800:1, under various compression parameters settings as well as different video formats. This paper also includes performance analysis of video stream rates with comparison into varying compression formats and Quantization Factors retrospective to Quality of Service (QoS). Projections were also performed as behavioral study on the effects of the available bandwidth with increased video capture sources and streaming processes.
2007-01-01T00:00:00ZAnalysis of real-time multiple source video streaming via wireless 5.8 GHz for intelligent traffic management systemBaskaran, V.M.Tiong, S.K.Jamaludin, M.Z.http://dspace.uniten.edu.my/jspui/handle/123456789/66082017-12-08T09:52:02Z2005-01-01T00:00:00ZTitle: Analysis of real-time multiple source video streaming via wireless 5.8 GHz for intelligent traffic management system
Authors: Baskaran, V.M.; Tiong, S.K.; Jamaludin, M.Z.
Abstract: This paper evaluates the performance of live compressed motion image transmission in coherence with the development of the Multiple Video Streaming and Compression (Multiple-VSCS) software, as applied for the Intelligent Traffic Management system. Motion Images of multiple sources are captured, jointly compressed and streamed real time via utilization of the 5.8 GHz OFDM Outdoor Wireless LAN network. Experiments were performed and analyzed to ascertain the reliability and potency of this application with improved bitstream rates as low as 50kbps and compression ratio rates as high as 1800:1, under various compression parameters settings as well as different video formats. This paper also includes performance analysis of video stream rates with comparison into varying compression formats and Quantization Factors retrospective to Quality of Service (QoS). Projections were also performed as behavioral study on the effects of the available bandwidth with increased video capture sources and streaming processes. © 2005 IEEE.
2005-01-01T00:00:00ZScalable real-time video encryption technique via wireless LAN 5.8 GHz for intelligent traffic management systemBaskaran, V.M.Tiong, S.K.Jamaludin, M.Z.http://dspace.uniten.edu.my/jspui/handle/123456789/66072017-12-08T09:52:02Z2005-01-01T00:00:00ZTitle: Scalable real-time video encryption technique via wireless LAN 5.8 GHz for intelligent traffic management system
Authors: Baskaran, V.M.; Tiong, S.K.; Jamaludin, M.Z.
Abstract: This paper analyzes and applies scalable encryption methods to secure live video transmission in coherence with development of the Multiple Video Streaming and Compression (Multiple-VSCS) software, as applied for the Intelligent Traffic Management system. Motion images are captured, jointly compressed, encrypted and streamed real time via utilization of the 5.8 GHz OFDM Outdoor Wireless LAN network. Theoretical comparisons are made with current and previous encryption standards to ascertain the appropriate encryption solution. The selected standard is then developed and embedded into the H.263 video compression standard with different configurations at the DCT process to analyze the behavior of the encrypted stream rates with respect to quality of the scrambled images. The behavior is based on the amount of DCT coefficients subjected to encryption process with differences in the bit rates averaging between 40% and 90% under these conditions. © 2005 IEEE.
2005-01-01T00:00:00ZPerformance study of multiple source video streaming via wireless 5.8 GHz for intelligent traffic management systemBaskaran, V.M.Tiong, S.K.Jamaludin, M.Z.http://dspace.uniten.edu.my/jspui/handle/123456789/66092017-12-08T09:52:02Z2005-01-01T00:00:00ZTitle: Performance study of multiple source video streaming via wireless 5.8 GHz for intelligent traffic management system
Authors: Baskaran, V.M.; Tiong, S.K.; Jamaludin, M.Z.
Abstract: This paper describes the performance evaluation on the Multiple Video Source Capture and Streaming software (Multiple-VSCS) developed for the Intelligent Traffic Management system. Motion Images captured from multiple independent capture devices are compressed and streamed to a remote location via the 5.8 GHz Wireless LAN network. The compression algorithm used here is the current ITU H.263 codec. Performance evaluation tests measured the compressed video stream rate at an average of 500 kbps with total bandwidth utilization at 1.02 %. The performance evaluation will also include measurements of video transfer rates, compression ratio rates with comparison to theoretical ratios. Projections are also made with correlation to increased video transfer rates from multiple sources at different compression formats. © 2005 IEEE.
2005-01-01T00:00:00ZOptimization of the Time of Task Scheduling for Dual Manipulators using a Modified Electromagnetism-Like Algorithm and Genetic AlgorithmAbed, I.A.Koh, S.P.Sahari, K.S.M.Jagadeesh, P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/66832018-01-03T01:52:13Z2014-01-01T00:00:00ZTitle: Optimization of the Time of Task Scheduling for Dual Manipulators using a Modified Electromagnetism-Like Algorithm and Genetic Algorithm
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Jagadeesh, P.; Tiong, S.K.
Abstract: A method based on a modified electromagnetism-like with two-direction local search algorithm (MEMTDLS) and genetic algorithm (GA) is proposed to determine the optimal time of task scheduling for dual-robot manipulators. A GA is utilized to calculate the near-optimal task scheduling for both robots, and the MEMTDLS is recommended as a suitable alternative in obtaining multiple solutions at each task point for both manipulators with minimal error. During the course of the tour, the robots move from point to point with a short cycle time, while ensuring that no collision occurs between the two manipulators themselves or between the dual manipulators and the static obstacles in the workspace. The movement and the configurations of the manipulators at the task points were illustrated using a simulator that was developed via Visual Basic.Net. The method is verified using two simulators that are used as examples for two identical four-link planar robots that work in the environment, with square-shaped obstacles cluttered at different locations. © 2014 King Fahd University of Petroleum and Minerals.
2014-01-01T00:00:00ZSolving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travelAbed, I.A.Koh, S.P.Sahari, K.S.M.Tiong, S.K.Tan, N.M.L.http://dspace.uniten.edu.my/jspui/handle/123456789/57892018-01-03T01:49:09Z2014-01-01T00:00:00ZTitle: Solving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travel
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Tiong, S.K.; Tan, N.M.L.
Abstract: A new modification of Electromagnetism-like (EM) algorithm which incorporating the Record-to-Record Travel (RRT) local search algorithm; namely MEMR has been developed to solve the problem of Inverse Kinematics (IK) for a four Degree-of-Freedom (DOF) manipulator. The proposed method is able to generate multiple robot configurations for the IK test performed at different end effect or positions. In addition, the comparison between the proposed MEMR and Genetic Algorithm (GA) was carried out using two mathematical test functions; De Jong and Rastrigin. The tests results show that the proposed MEMR is comparable in performance to GA in terms of both convergence speed and error rate. © Maxwell Scientific Organization, 2014.
2014-01-01T00:00:00ZModeling of energy efficiency in heterogeneous networkAbdulkafi, A.A.Tiong, S.K.Chieng, D.Ting, A.Ghaleb, A.M.Koh, J.http://dspace.uniten.edu.my/jspui/handle/123456789/57952018-01-03T02:05:18Z2013-01-01T00:00:00ZTitle: Modeling of energy efficiency in heterogeneous network
Authors: Abdulkafi, A.A.; Tiong, S.K.; Chieng, D.; Ting, A.; Ghaleb, A.M.; Koh, J.
Abstract: Cellular networks are undergoing transformation from conventional homogeneous macro Base Stations (BSs) to Heterogeneous Network (HetNet). This new paradigm not only offers a significant improvement in the overall network capacity or user data rate; it also promises an improvement in the overall network Energy Efficiency (EE). In this study, a theoretical model for evaluating the EE in HetNet is developed. A HetNet generally consists of different types of Base Stations (BSs) which operate in harmony towards a set of common goals defined by the network operator such as coverage and capacity improvement. Each BS may differ in terms of transmit power, achievable data rate, coverage, BS density and EE, under different network deployment scenarios. The results show that the picocell strongly impacts the Energy Efficiency (EE) of the HetNet as compared to microcell. More specifically it is observed that certain ratios of microcells and picocells per macro BS will result in sub-optimal of Area Energy Efficiency (AEE). It is shown that the AEE of HetNet also increases as the percentage area of macro BS overlaid by smaller cells and the density of micro/picocells increases. © Maxwell Scientific Organization, 2013.
2013-01-01T00:00:00ZAvoiding self nulling by using linear constraint minimum variance beamforming in smart antennaSalem, B.Tiong, S.K.Koh, S.P.Darzi, S.http://dspace.uniten.edu.my/jspui/handle/123456789/57982018-01-03T02:43:17Z2013-01-01T00:00:00ZTitle: Avoiding self nulling by using linear constraint minimum variance beamforming in smart antenna
Authors: Salem, B.; Tiong, S.K.; Koh, S.P.; Darzi, S.
Abstract: The beam forming technique is important in smart antenna systems to enhance the data rates, null steering and coverage. This study presents two methods of beamformeing algorithm; Minimum Variance Distortion less Response (MVDR) and Linear Constraint Minimum Variance (LCMV). MVDR and LCMV techniques form radiation beams based on the received weight vector of the desired signal. The LCMV technique is found to be efficient than the MVDR in self-null even if the interference signal is closer from the desired signal. Simulation has been carried out to validate these two techniques. The four elements of the linear array smart antenna are used in our simulation program with the operation frequency around 2.3 GHz, noise power 0.5dB and the spacing between elements is 0.5 λ. The result of the simulation reveals that both the modes are capable of providing high output power; however they need the direction of all the incoming sources, which is practically difficult to obtain. Nevertheless the MVDR beam forming minimizes the multi-path fading problem, by adding the multi-path signal, which increases the strength of the desired signal and nullifies the interference. © Maxwell Scientific Organization, 2013.
2013-01-01T00:00:00ZLink performance enhancement for image transmission with FEC in Wireless Sensor NetworksYap, D.F.W.Tiong, S.K.Koh, J.Andito, D.P.Lim, K.C.Yeo, W.K.http://dspace.uniten.edu.my/jspui/handle/123456789/58072018-01-03T03:57:50Z2012-01-01T00:00:00ZTitle: Link performance enhancement for image transmission with FEC in Wireless Sensor Networks
Authors: Yap, D.F.W.; Tiong, S.K.; Koh, J.; Andito, D.P.; Lim, K.C.; Yeo, W.K.
Abstract: Wireless Sensor Networks (WSN) is formerly created to support text-based data communication. However, by improving link level mechanism of WSN with Error Control Codng (ECC), reliable multimedia transmission could be realized. This paper addresses the performance issue of transferring multimedia data, particularly still image data, using real sensor motes platform. An X-ray image is transferred from one mote to other mote in one hop scenario. Forward Error Correction (FEC) and interleaving technique are used to design the code that capable of handling both erasure and noise in the received packet. The results show that erasure code can effectively combat the effect of random noise in one packet despite its number as well as recover small quantity of lost packet. Fdermore, the scheme can increase the image PSNR (Peak Signal to Noise Ratio) up to 18.41 dB as compared to the uncoded counterpart © 2012 Asian Network for Scientific Information.
2012-01-01T00:00:00ZComparison between genetic algorithm and electromagnetism-like algorithm for solving inverse kinematicsAbed, I.A.Koh, S.P.Mohamed Sahari, K.S.Tiong, S.K.Yap, D.F.W.http://dspace.uniten.edu.my/jspui/handle/123456789/58042018-01-03T03:46:34Z2012-01-01T00:00:00ZTitle: Comparison between genetic algorithm and electromagnetism-like algorithm for solving inverse kinematics
Authors: Abed, I.A.; Koh, S.P.; Mohamed Sahari, K.S.; Tiong, S.K.; Yap, D.F.W.
Abstract: A comparison study between Electromagnetism-Like Algorithm (EM) and Genetic Algorithm (GA) has been presented in this work to solve the Inverse Kinematics (IK) of a four-link planar robot manipulator. The comparison is focused on some points for both algorithms like the accuracy of the results and the speed of convergence. Different target points have been taken to check the performance of each algorithm to solve the IK problem. The results showed that EM algorithm needs less population size and number of generations to get the true solution. There are multiple robot configurations at the goal points and both algorithms are able to find these solutions at each point. Self developed software simulator is used to display some of these solutions at each goal position. © IDOSI Publications, 2012.
2012-01-01T00:00:00ZA hybrid artificial immune systems for multimodal function optimization and its application in engineering problemYap, D.F.W.Koh, S.P.Tiong, S.K.Prajindra, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/59982018-01-03T03:43:27Z2012-01-01T00:00:00ZTitle: A hybrid artificial immune systems for multimodal function optimization and its application in engineering problem
Authors: Yap, D.F.W.; Koh, S.P.; Tiong, S.K.; Prajindra, S.K.
Abstract: Lately, the field of Artificial Immune Systems (AIS) has attracted wide attention among researchers as the algorithm is able to improve local searching ability and efficiency. However, the rate of convergence for AIS is rather slow as compared to other Evolutionary Algorithms. Alternatively, Particle Swarm Optimization (PSO) has been used effectively in solving complicated optimization problems with simple coding and lesser parameters, but it tends to converge prematurely. Thus, the good features of AIS and PSO are combined in ordertoreduce their shortcomings. By comparing the optimization results of the mathematical functions and the engineering problem using hybrid AIS (HAIS) and AIS, it is observed that HAIS has better performances in terms of accuracy, convergence rate and stability. © Springer Science+Business Media B.V. 2011.
2012-01-01T00:00:00ZComparison of supervised learning techniques for non-technical loss detection in power utilityYap, K.S.Tiong, S.K.Nagi, J.Koh, J.S.P.Nagi, F.http://dspace.uniten.edu.my/jspui/handle/123456789/58082018-01-03T04:05:17Z2012-01-01T00:00:00ZTitle: Comparison of supervised learning techniques for non-technical loss detection in power utility
Authors: Yap, K.S.; Tiong, S.K.; Nagi, J.; Koh, J.S.P.; Nagi, F.
Abstract: Non technical losses (NTLs) originating from electricity theft and other customer malfeasances are a problem in the electricity supply industry. In recent times, electricity consumer dishonesty has become a universal problem faced by all power utilities. Previous work carried out for NTL detection resulted in a Support Vector Machine (SVM) based detection framework. The present study performs a comparative study for NTL detection using supervised machine learning techniques such as the: Back-Propagation Neural Network (BPNN) and Online-sequential Extreme Learning Machine (OS-ELM). Model testing is performed using historical customer consumption data for three towns within peninsular Malaysia. The detection hit-rate of all compared models is obtained from TNB Distribution (TNBD) Sdn. Bhd. for onsite customer inspection. Experimental results obtained indicate that the BPNN detection model achieves the lowest average detection hit-rate of 36.07%, while the OS-ELM model obtains a slightly higher average detection hit-rate of 51.38%. The previously proposed SVM-based NTL detection model outperforms the BPNN and OS-ELM by far with the highest average detection hit-rate of 60.75%. This indicates that the use of a SVM-based soft-margin approach results in a better generalization performance for the application of NTL detection as compared to the BPNN and OS-ELM schemes. © 2012 Praise Worthy Prize S.r.l. -All rights reserved. - All rights reserved.
2012-01-01T00:00:00ZGlobal optimal analysis of variant genetic operations in solar trackingFam, D.F.Koh, S.P.Tiong, S.K.Chong, K.H.http://dspace.uniten.edu.my/jspui/handle/123456789/58102018-01-03T07:10:15Z2012-01-01T00:00:00ZTitle: Global optimal analysis of variant genetic operations in solar tracking
Authors: Fam, D.F.; Koh, S.P.; Tiong, S.K.; Chong, K.H.
Abstract: Genetic Algorithms (GAs), Evolution Strategies (ES), Evolutionary Programming (EP) and Genetic Programming (GP) are some of the best known types of Evolutionary Algorithm (EA)where it is a class of global search algorithms inspired by natural evolution. Lots of research has been carried out in solar tracking system using different types of Evolutionary Algorithm. In this research, genetic algorithm is explored to maximize the performance of solar tracking system. This work evaluates the best combination of GA parameters by always fine-tuning the position of solar tracking prototype to receive maximum solar radiation. Both software and hardware have been developed to simulate related genetic algorithm results using a combination of variant genetic operators. Under conventional genetic algorithm operation, it is concluded that genetic algorithm with selective clonal mutation is able to produce the best fitness value at 0.98027 with both axles X and Y with inclination of +2 degree to the sun position.
2012-01-01T00:00:00ZPerformance comparison of MVDR and LCMV beamforming algorithm in 2.3 GHz adaptive antenna systemSalem, B.Tiong, S.K.Koh, S.P.Hock, G.C.http://dspace.uniten.edu.my/jspui/handle/123456789/58122018-01-03T07:36:49Z2012-01-01T00:00:00ZTitle: Performance comparison of MVDR and LCMV beamforming algorithm in 2.3 GHz adaptive antenna system
Authors: Salem, B.; Tiong, S.K.; Koh, S.P.; Hock, G.C.
Abstract: The blind beamforming technique is employed in the broadband wireless mobile systems to enhance the cellular systems in the aspect of capacity, data rates, null steering and coverage. This paper presents two methods of beamforming algorithm; Minimum Variance Distortionless Response (MVDR) and Linear Constraint Minimum Variance (LCMV). MVDR and LCMV techniques form radiation beams based on the received weight vector of the desired signal. Simulation has been carried out to validate these two techniques. Four elements of the linear array antenna are used in our simulation program with the carrier frequency around 2.3 GHz, noise power 0.5dB, and the spacing between elements is 0.5 λ. The result of the simulation reveals that both the modes are capable of providing high output power; however direction of all the incoming sources is required, which is practically difficult to obtain. Nevertheless the MVDR beamforming, minimizes the multi-path fading problem, by adding the multi-path signal, which increases the strength of the desired signal and nullifies the interference. Overall, the MVDR technique is more accurate than the LCMV to null to find the interference source and directing radiation lobe with high power towards the desired signal. © 2012 Praise Worthy Prize S.r.l.-All rights reserved.
2012-01-01T00:00:00ZPath selection technique for highly transmission ratio and reliable routing in ManetJassim, H.S.Yussof, S.Tiong, S.K.Chong, K.H.Koh, S.P.http://dspace.uniten.edu.my/jspui/handle/123456789/58192018-01-03T08:12:02Z2011-01-01T00:00:00ZTitle: Path selection technique for highly transmission ratio and reliable routing in Manet
Authors: Jassim, H.S.; Yussof, S.; Tiong, S.K.; Chong, K.H.; Koh, S.P.
Abstract: Mobile ad-hoc network (MANET) is collection of wireless nodes that operates without using a centralized network infrastructure such as a base station. Since the wireless range is limited, the nodes mutually cooperate with their neighbors in order to extend the overall communication range of the network for forwarding packets. Ad-hoc On-demand Distance Vector (AODV) is one of the commonly used protocols in ad-hoc networks. AODV is a dynamic routing protocol that is able to find the shortest path from a source node to a destination node in MANET based on hop count. However, due to the nature of MANET, it is very easy to introduce malicious nodes in MANET. These malicious nodes may try to compromise the routing protocol functionality and make MANET vulnerable to security attacks which lead to unreliable routing. Therefore, security has become a primary concern in providing protected communication among nodes in MANET. In this study, we propose a Reliable Dynamic Trust-based Routing (RDTR) protocol by integrating a trust mechanism with a shortest path routing algorithm for establishing and maintaining trustworthy routes in MANET. © Asian Network for Scientific Information.
2011-01-01T00:00:00ZInvestigation of induction motor parameter identification using particle swarm optimization-based RBF neural network (PSO-RBFNN)Rashag, H.F.Koh, S.P.Tiong, S.K.Chong, K.H.Abdalla, A.N.http://dspace.uniten.edu.my/jspui/handle/123456789/58202018-01-03T08:14:54Z2011-01-01T00:00:00ZTitle: Investigation of induction motor parameter identification using particle swarm optimization-based RBF neural network (PSO-RBFNN)
Authors: Rashag, H.F.; Koh, S.P.; Tiong, S.K.; Chong, K.H.; Abdalla, A.N.
Abstract: High dynamic performance of induction motor drives is required for accurate system information. From the actual parameters, it is possible to design high performance induction motor drive controllers. In this paper, improving the induction motor performance using intelligent parameter identification was proposed. First, machine model parameters were presented by a set of time-varying differential equations. Second, estimation of each parameter was achieved by minimizing the experimental response based on matching of the stator current, voltage and rotor speed. Finally, simulation results demonstrate the effectiveness of the proposed method and great improvement of induction motor performance. © 2011 Academic Journals.
2011-01-01T00:00:00ZArtificial immune system based remainder method for multimodal mathematical function optimizationYap, D.F.W.Koh, S.P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/58172018-01-04T02:57:20Z2011-01-01T00:00:00ZTitle: Artificial immune system based remainder method for multimodal mathematical function optimization
Authors: Yap, D.F.W.; Koh, S.P.; Tiong, S.K.
Abstract: Artificial immune system (AIS) is one of the nature-inspired algorithm for solving optimization problems. In AIS, clonal selection algorithm (CSA) is able to improve global searching ability compare to other meta-heuristic methods. However, the CSA rate of convergence and accuracy can be further improved as the hyper mutation in CSA itself cannot always guarantee a better solution. Conversely, Genetic Algorithms (GAs) and Particle Swarm Optimization (PSO) have been used efficiently in solving complex optimization problems, but they have an inclination to converge prematurely. In this work, the CSA is modified using the best solutions for each exposure (iteration) namely Single Best Remainder (SBR) - CSA. Simulation results show that the proposed algorithm is able to enhance the performance of the conventional CSA in terms of accuracy and stability for single objective functions. © IDOSI Publications, 2011.
2011-01-01T00:00:00ZA swarm-based artificial immune system for solving multimodal functionsYap, D.F.W.Koh, S.P.Tiong, S.K.Prajindra, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/60002018-01-04T02:47:51Z2011-01-01T00:00:00ZTitle: A swarm-based artificial immune system for solving multimodal functions
Authors: Yap, D.F.W.; Koh, S.P.; Tiong, S.K.; Prajindra, S.K.
Abstract: Artificial Immune Systems (AIS) have attracted enormous attention among researchers because the algorithms are able to improve global searching ability and efficiency. Nevertheless, the rate of convergence for AIS is relatively slow compared to other metaheuristic algorithms. On the other hand, genetic algorithms (GAs) and particle swarm optimization (PSO) have been used successfully in solving optimization problems, although they tend to converge prematurely. Therefore, the good attributes of AIS and PSO are merged in order to reduce this limitation. It is observed that the proposed hybrid AIS (HAIS) achieved better performances in terms of convergence rate, accuracy, and stability against GA and AIS by comparing the optimization results of the mathematical functions. A similar result was achieved by HAIS in the engineering problem when compared to GA, PSO, and AIS. Copyright © 2011 Taylor & Francis Group, LLC.
2011-01-01T00:00:00ZA comparative analysis on the performance of particle swarm optimization and artificial immune systems for mathematical test functionsYap, D.F.W.Koh, S.P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/58372018-01-05T01:47:01Z2009-01-01T00:00:00ZTitle: A comparative analysis on the performance of particle swarm optimization and artificial immune systems for mathematical test functions
Authors: Yap, D.F.W.; Koh, S.P.; Tiong, S.K.
Abstract: Over the years, the area of Artificial Immune Systems (AIS) has drawn wide attention among researchers as the algorithm is able to enhance local searching ability and efficiency. Alternatively, Particle Swarm Optimization (PSO) has been used effectively in solving optimization problems. This paper compares the optimization results of the mathematical functions using AIS and PSO. The numerical results show that both PSO and AIS give comparable fitness solutions with the former performing about 56 percent faster than the latter. Conversely, for simpler mathematical functions, AIS performs marginally faster than PSO at about 14 percent while maintaining good accuracy of the objective value. © 2009, INSInet Publication.
2009-01-01T00:00:00ZEffects of second order dispersion in free space optical communicationYap, D.F.W.Wong, V.C.Koh, S.P.Tiong, S.K.Mohd Tahir, M.A.E.http://dspace.uniten.edu.my/jspui/handle/123456789/58352018-01-04T08:32:08Z2010-01-01T00:00:00ZTitle: Effects of second order dispersion in free space optical communication
Authors: Yap, D.F.W.; Wong, V.C.; Koh, S.P.; Tiong, S.K.; Mohd Tahir, M.A.E.
Abstract: Free Space Optic (FSO) can be considered as an attractive option to fiber optic. FSO has the capability to go beyond the limit of fiber optics. Unfortunately, due to the effects of dispersion in the atmosphere, FSO, as a point-to-point communication system that requires line-of-sight transmission; suffers from attenuation and signal loss. Thus, practical and detailed research is needed to improve this wireless system. In this study, simulation on FSO propagation using measured parameter values was carried out in order to gain better understanding on the pulse behavior in free space with better level of accuracy. Using MATLAB and experimental parameter values, a more precise model can be obtained and analyzed. This will allow some level of prediction on the behavior of the propagating light pulse in the atmosphere and subsequently the FSO system performance can be further improved. © 2010 Asian Network for Scientific Information.
2010-01-01T00:00:00ZParallel distributed computational microcontroller system for adaptive antenna downlink transmitter power optimizationSankar, K.P.Tiong, S.K.Koh, S.P.J.http://dspace.uniten.edu.my/jspui/handle/123456789/60032018-01-05T03:43:14Z2009-01-01T00:00:00ZTitle: Parallel distributed computational microcontroller system for adaptive antenna downlink transmitter power optimization
Authors: Sankar, K.P.; Tiong, S.K.; Koh, S.P.J.
Abstract: This paper presents a tested research concept that implements a complex evolutionary algorithm, genetic algorithm (GA), in a multi-microcontroller environment. Parallel Distributed Genetic Algorithm (PDGA) is employed in adaptive beam forming technique to reduce power usage of adaptive antenna at WCDMA base station. Adaptive antenna has dynamic beam that requires more advanced beam forming algorithm such as genetic algorithm which requires heavy computation and memory space. Microcontrollers are low resource platforms that are normally not associated with GAs, which are typically resource intensive. The aim of this project was to design a cooperative multiprocessor system by expanding the role of small scale PIC microcontrollers to optimize WCDMA base station transmitter power. Implementation results have shown that PDGA multi-microcontroller system returned optimal transmitted power compared to conventional GA. © 2009 WASET.ORG.
2009-01-01T00:00:00ZScaling effects on the dynamic characteristics of long-wavelength vertical-cavity surface-emitting lasers (VCSELs)Yap, D.F.W.Koh, S.P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/58542018-01-08T07:19:38Z2008-01-01T00:00:00ZTitle: Scaling effects on the dynamic characteristics of long-wavelength vertical-cavity surface-emitting lasers (VCSELs)
Authors: Yap, D.F.W.; Koh, S.P.; Tiong, S.K.
Abstract: The influence of the oxide aperture radius on the characteristics of a long-wavelength vertical-cavity surface-emitting laser (VCSEL) lasing at 1550 nm is presented in this paper. While previous works in the literature mostly investigate the scaling effects of short-wavelength VCSELs. The importance of studying the effects of long-wavelength operation should not be underestimated, as it could be used in fiber optics communication to mitigate dispersion and attenuation of the channel. Using the oxide-confined VCSEL model, the dynamic operations were examined taking into account the carrier-noise, photon-noise and phase-noise, including feedback of the external cavity. Our simulations show that by reducing the oxide aperture up to a given optimal radius, an improvement in the device's characteristics can be demonstrated. Below this value, performance degradation is expected due to increased diffraction losses, reduced confinement factor and enhanced spontaneous emission. © 2007 Elsevier Ltd. All rights reserved.
2008-01-01T00:00:00ZAnalysis of In-P based 1.55νm electrically pumped vertical-external- cavity surface-emitting lasersYap, D.F.W.Low, A.L.Y.Koh, S.P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/58552018-01-08T07:22:15Z2007-01-01T00:00:00ZTitle: Analysis of In-P based 1.55νm electrically pumped vertical-external- cavity surface-emitting lasers
Authors: Yap, D.F.W.; Low, A.L.Y.; Koh, S.P.; Tiong, S.K.
Abstract: In this paper, theoretical analysis of the In-P based 1.55νm electrically pumped vertical-external-cavity surface-emitting lasers is presented. Computational experimental results show that short-cavity VCSELs (vertical-cavity surface-emitting lasers) with weak external feedback exhibit an increase of 37% output power compared with the conventional VCSELs. In addition, with an optimized external feedback, the -3dB modulation bandwidth can be increased by approximately 5% and having a wider eye opening in a 40Gbits-1 transmission system. © IOP Publishing Ltd.
2007-01-01T00:00:00ZPendulum-like algorithm as a local search techniqueAbed, I.A.Koh, S.P.Sahari, K.S.M.Tiong, S.K.Younis, H.A.-K.Abed, A.A.http://dspace.uniten.edu.my/jspui/handle/123456789/69482018-01-11T08:27:25Z2016-01-01T00:00:00ZTitle: Pendulum-like algorithm as a local search technique
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Tiong, S.K.; Younis, H.A.-K.; Abed, A.A.
Abstract: The Pendulum-like algorithm is based on the concepts of the pendulum. All the ideas that are derived have been embedded into the suggested method. The Pendulum-like algorithm introduced, is expected to provide very good results in solving the optimization problems. This is due to the fact that Pendulum-like algorithm is a method with directed force which is reduced gradually with approximation to the global solution and it also uses the idea of back and forth movement to enhance the solution. Thus, the Pendulum-like algorithm would be integrated with the attraction-repulsion mechanism to introduce a very promising problem solving algorithm. The parameters of the proposed algorithm are evaluated and tested to prove the effect of each one on the algorithm. Also, the results of the algorithm are simulated the same behavior for the parameters of physical pendulum. © 2016 IEEE.
2016-01-01T00:00:00ZOptimization of the Time of Task Scheduling for Dual Manipulators using a Modified Electromagnetism-Like Algorithm and Genetic AlgorithmAbed, I.A.Koh, S.P.Sahari, K.S.M.Jagadeesh, P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/69842018-01-11T08:27:44Z2014-01-01T00:00:00ZTitle: Optimization of the Time of Task Scheduling for Dual Manipulators using a Modified Electromagnetism-Like Algorithm and Genetic Algorithm
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Jagadeesh, P.; Tiong, S.K.
Abstract: A method based on a modified electromagnetism-like with two-direction local search algorithm (MEMTDLS) and genetic algorithm (GA) is proposed to determine the optimal time of task scheduling for dual-robot manipulators. A GA is utilized to calculate the near-optimal task scheduling for both robots, and the MEMTDLS is recommended as a suitable alternative in obtaining multiple solutions at each task point for both manipulators with minimal error. During the course of the tour, the robots move from point to point with a short cycle time, while ensuring that no collision occurs between the two manipulators themselves or between the dual manipulators and the static obstacles in the workspace. The movement and the configurations of the manipulators at the task points were illustrated using a simulator that was developed via Visual Basic.Net. The method is verified using two simulators that are used as examples for two identical four-link planar robots that work in the environment, with square-shaped obstacles cluttered at different locations. © 2014 King Fahd University of Petroleum and Minerals.
2014-01-01T00:00:00ZSolving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travelAbed, I.A.Koh, S.P.Sahari, K.S.M.Tiong, S.K.Tan, N.M.L.http://dspace.uniten.edu.my/jspui/handle/123456789/69852018-01-11T08:27:44Z2014-01-01T00:00:00ZTitle: Solving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travel
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Tiong, S.K.; Tan, N.M.L.
Abstract: A new modification of Electromagnetism-like (EM) algorithm which incorporating the Record-to-Record Travel (RRT) local search algorithm; namely MEMR has been developed to solve the problem of Inverse Kinematics (IK) for a four Degree-of-Freedom (DOF) manipulator. The proposed method is able to generate multiple robot configurations for the IK test performed at different end effect or positions. In addition, the comparison between the proposed MEMR and Genetic Algorithm (GA) was carried out using two mathematical test functions; De Jong and Rastrigin. The tests results show that the proposed MEMR is comparable in performance to GA in terms of both convergence speed and error rate. © Maxwell Scientific Organization, 2014.
2014-01-01T00:00:00ZUsing Electromagnetism-like algorithm and genetic algorithm to optimize time of task scheduling for dual manipulatorsAbed, I.A.Sahari, K.S.M.Koh, S.P.Tiong, S.K.Jagadeesh, P.http://dspace.uniten.edu.my/jspui/handle/123456789/69872018-01-11T08:27:45Z2013-01-01T00:00:00ZTitle: Using Electromagnetism-like algorithm and genetic algorithm to optimize time of task scheduling for dual manipulators
Authors: Abed, I.A.; Sahari, K.S.M.; Koh, S.P.; Tiong, S.K.; Jagadeesh, P.
Abstract: A method based on Electromagnetism-Like algorithm (EM) and Genetic Algorithm (GA) is proposed to determine the time-optimal task scheduling for dual robot manipulators. GA is utilized to calculate the near-optimal task scheduling for the two robots. On top of that, the EM is recommended as a suitable alternative to obtain multiple solutions at each task points for both manipulators with less error. During the course of the tour, the dual robots move from point to point with less cycle time, while ensuring that no collision occurs between the two manipulators or between the dual manipulators and the static obstacles in the workspace. The movement and the configurations of the manipulators at the task points were visualized using a simulator developed via Visual Basic. Net. The method is verified using two simulators acting as examples for two identical four-link planar robots working in the environment, with square-shaped obstacles cluttered at different locations. © 2013 IEEE.
2013-01-01T00:00:00ZComparison between genetic algorithm and electromagnetism-like algorithm for solving inverse kinematicsAbed, I.A.Koh, S.P.Mohamed Sahari, K.S.Tiong, S.K.Yap, D.F.W.http://dspace.uniten.edu.my/jspui/handle/123456789/69942018-01-11T08:27:48Z2012-01-01T00:00:00ZTitle: Comparison between genetic algorithm and electromagnetism-like algorithm for solving inverse kinematics
Authors: Abed, I.A.; Koh, S.P.; Mohamed Sahari, K.S.; Tiong, S.K.; Yap, D.F.W.
Abstract: A comparison study between Electromagnetism-Like Algorithm (EM) and Genetic Algorithm (GA) has been presented in this work to solve the Inverse Kinematics (IK) of a four-link planar robot manipulator. The comparison is focused on some points for both algorithms like the accuracy of the results and the speed of convergence. Different target points have been taken to check the performance of each algorithm to solve the IK problem. The results showed that EM algorithm needs less population size and number of generations to get the true solution. There are multiple robot configurations at the goal points and both algorithms are able to find these solutions at each point. Self developed software simulator is used to display some of these solutions at each goal position. © IDOSI Publications, 2012.
2012-01-01T00:00:00ZNew development of analysis tool for optimizing generation cost with gas emission via an electromagnetism like algorithmAlbert, F.Y.C.Koh, S.P.Chen, C.P.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/57842018-02-08T00:54:56Z2016-01-01T00:00:00ZTitle: New development of analysis tool for optimizing generation cost with gas emission via an electromagnetism like algorithm
Authors: Albert, F.Y.C.; Koh, S.P.; Chen, C.P.; Tiong, S.K.
Abstract: This paper addresses the preliminary new development results of the evolutionary algorithm technique to optimize the formulated problems incorporating the generation cost with emission gas as objective function or constraints. The power generation cost with emission gas are a complex problem which also the major concerns in electric power generation systems in the Environmental or Economic Dispatch Problems (EDP). Thus, due to environmental concern the electrical utilities required to minimize the emission level while optimizing the thermal generating units at a minimum generating cost and hence, satisfying the load demand and the emissions. In this work the electromagnetism-Like algorithm (EML) has been employed for optimizing generation cost and emission constraints economic dispatch problem. The proposed decision analysis tool software in this work will optimize the generation cost with emission gas objective function. The best generation cost with emission gas solution are obtained from different fuel technology via the developed software. © 2016 Penerbit UTM Press. All rights reserved.
2016-01-01T00:00:00ZHigh performance of space vector modulation direct torque control SVM-DTC based on amplitude voltage and stator flux angleRashag, H.F.Koh, S.P.Chong, K.H.Tiong, S.K.Tan, N.M.L.Abdalla, A.N.http://dspace.uniten.edu.my/jspui/handle/123456789/57972018-02-09T01:02:51Z2013-01-01T00:00:00ZTitle: High performance of space vector modulation direct torque control SVM-DTC based on amplitude voltage and stator flux angle
Authors: Rashag, H.F.; Koh, S.P.; Chong, K.H.; Tiong, S.K.; Tan, N.M.L.; Abdalla, A.N.
Abstract: Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM), amplitude of voltage in direct- quadrature reference frame (d-q reference) and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in α and β frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steadand transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range. © Maxwell Scientific Organization, 2013.
2013-01-01T00:00:00ZDTC-SVM based on PI torque and PI flux controllers to achieve high performance of induction motorRashag, H.F.Tan, N.M.L.Koh, S.P.Abdalla, A.N.Chong, K.H.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/57882018-02-09T00:59:50Z2014-01-01T00:00:00ZTitle: DTC-SVM based on PI torque and PI flux controllers to achieve high performance of induction motor
Authors: Rashag, H.F.; Tan, N.M.L.; Koh, S.P.; Abdalla, A.N.; Chong, K.H.; Tiong, S.K.
Abstract: The fundamental idea of direct torque control of induction machines is investigated in order to emphasize the property produced by a given voltage vector on stator flux and torque variations. The proposed control system is based on Space Vector Modulation (SVM) of electrical machines, Improvement model reference adaptive system, real time of stator resistance and estimation of stator flux. The purpose of this control is to minimize electromagnetic torque and flux ripple and minimizing distortion of stator current. In this proposed method, PI torque and PI flux controller are designed to achieve estimated torque and flux with good tracking and fast response with reference torque and there is no steady state error. In addition, design of PI torque and PI flux controller are used to optimize voltages in d-q reference frame that applied to SVM. The simulation Results of proposed DTC-SVM have complete excellent performance in steady and transient states as compared with classical DTC-SVM. © Maxwell Scientific Organization, 2014.
2014-01-01T00:00:00ZAn adaptive error correction system for microwave transmission systemsCheah, C.L.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/87142018-02-20T06:01:45Z2009-01-01T00:00:00ZTitle: An adaptive error correction system for microwave transmission systems
Authors: Cheah, C.L.; Tiong, S.K.
Abstract: This paper proposes an adaptive error correction system for microwave transmission systems. Unlike most previous adaptive error correction systems which change to a stronger code for error correction based on either packet losses or erroneous condition, the proposed system is able to do so before an error occurs. Simulation results show that the proposed system can maintain the output bit error rate (BER) below a target BER by assigning an appropriate value of waiting delay before changing to a weaker code.
2009-01-01T00:00:00ZComparison of supervised learning techniques for non-technical loss detection in power utilityYap, K.S.Tiong, S.K.Nagi, J.Koh, J.S.P.Nagi, F.http://dspace.uniten.edu.my/jspui/handle/123456789/89082018-02-21T04:42:08Z2012-01-01T00:00:00ZTitle: Comparison of supervised learning techniques for non-technical loss detection in power utility
Authors: Yap, K.S.; Tiong, S.K.; Nagi, J.; Koh, J.S.P.; Nagi, F.
Abstract: Non technical losses (NTLs) originating from electricity theft and other customer malfeasances are a problem in the electricity supply industry. In recent times, electricity consumer dishonesty has become a universal problem faced by all power utilities. Previous work carried out for NTL detection resulted in a Support Vector Machine (SVM) based detection framework. The present study performs a comparative study for NTL detection using supervised machine learning techniques such as the: Back-Propagation Neural Network (BPNN) and Online-sequential Extreme Learning Machine (OS-ELM). Model testing is performed using historical customer consumption data for three towns within peninsular Malaysia. The detection hit-rate of all compared models is obtained from TNB Distribution (TNBD) Sdn. Bhd. for onsite customer inspection. Experimental results obtained indicate that the BPNN detection model achieves the lowest average detection hit-rate of 36.07%, while the OS-ELM model obtains a slightly higher average detection hit-rate of 51.38%. The previously proposed SVM-based NTL detection model outperforms the BPNN and OS-ELM by far with the highest average detection hit-rate of 60.75%. This indicates that the use of a SVM-based soft-margin approach results in a better generalization performance for the application of NTL detection as compared to the BPNN and OS-ELM schemes. © 2012 Praise Worthy Prize S.r.l. -All rights reserved. - All rights reserved.
2012-01-01T00:00:00ZA computational intelligence scheme for the prediction of the daily peak loadNagi, J.Yap, K.S.Nagi, F.Tiong, S.K.Ahmed, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/89132018-02-21T04:42:12Z2011-01-01T00:00:00ZTitle: A computational intelligence scheme for the prediction of the daily peak load
Authors: Nagi, J.; Yap, K.S.; Nagi, F.; Tiong, S.K.; Ahmed, S.K.
Abstract: Forecasting of future electricity demand is very important for decision making in power system operation and planning. In recent years, due to privatization and deregulation of the power industry, accurate electricity forecasting has become an important research area for efficient electricity production. This paper presents a time series approach for mid-term load forecasting (MTLF) in order to predict the daily peak load for the next month. The proposed method employs a computational intelligence scheme based on the self-organizing map (SOM) and support vector machine (SVM). According to the similarity degree of the time series load data, SOM is used as a clustering tool to cluster the training data into two subsets, using the Kohonen rule. As a novel machine learning technique, the support vector regression (SVR) is used to fit the testing data based on the clustered subsets, for predicting the daily peak load. Our proposed SOM-SVR load forecasting model is evaluated in MATLAB on the electricity load dataset provided by the Eastern Slovakian Electricity Corporation, which was used in the 2001 European Network on Intelligent Technologies (EUNITE) load forecasting competition. Power load data obtained from (i) Tenaga Nasional Berhad (TNB) for peninsular Malaysia and (ii) PJM for the eastern interconnection grid of the United States of America is used to benchmark the performance of our proposed model. Experimental results obtained indicate that our proposed SOM-SVR technique gives significantly good prediction accuracy for MTLF compared to previously researched findings using the EUNITE, Malaysian and PJM electricity load datasets. © 2011 Elsevier B.V. All rights reserved.
2011-01-01T00:00:00ZHigh performance of space vector modulation direct torque control SVM-DTC based on amplitude voltage and stator flux angleRashag, H.F.Koh, S.P.Chong, K.H.Tiong, S.K.Tan, N.M.L.Abdalla, A.N.http://dspace.uniten.edu.my/jspui/handle/123456789/89992018-02-21T04:49:49Z2013-01-01T00:00:00ZTitle: High performance of space vector modulation direct torque control SVM-DTC based on amplitude voltage and stator flux angle
Authors: Rashag, H.F.; Koh, S.P.; Chong, K.H.; Tiong, S.K.; Tan, N.M.L.; Abdalla, A.N.
Abstract: Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM), amplitude of voltage in direct- quadrature reference frame (d-q reference) and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in α and β frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steadand transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range. © Maxwell Scientific Organization, 2013.
2013-01-01T00:00:00ZImproved close loop stator flux estimation of direct torque control driveRashag, H.F.Koh, S.P.Abdalla, A.N.Tan, N.M.L.Chong, K.H.Tiong, S.K.Jaber, A.S.http://dspace.uniten.edu.my/jspui/handle/123456789/90042018-02-21T04:49:51Z2012-01-01T00:00:00ZTitle: Improved close loop stator flux estimation of direct torque control drive
Authors: Rashag, H.F.; Koh, S.P.; Abdalla, A.N.; Tan, N.M.L.; Chong, K.H.; Tiong, S.K.; Jaber, A.S.
Abstract: In conventional direct torque controlled (DTC) induction motor drive, there is usually undesired torque and flux ripple. In this paper close loop stator flux estimation of DTC with space vector modulation under heavy load at low speed was proposed. First, brief description of stator currents in direct-quadrature reference frame with voltage model. Second, close loop stator flux feedback used through PID controller to correct the value of stator flux estimation and eliminate error. In addition, low pass filter also used instead of pure integration to avoid saturation problem. Finally, simulation results show that the flux and torque ripples are greatly reduced when compared with open loop of stator flux estimation. © 2012 Published by Elsevier Ltd.
2012-01-01T00:00:00ZNon-technical loss analysis for detection of electricity theft using support vector machinesNagi, J.Mohammad, A.M.Yap, K.S.Tiong, S.K.Ahmed, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/89302018-02-21T04:42:19Z2008-01-01T00:00:00ZTitle: Non-technical loss analysis for detection of electricity theft using support vector machines
Authors: Nagi, J.; Mohammad, A.M.; Yap, K.S.; Tiong, S.K.; Ahmed, S.K.
Abstract: Electricity consumer dishonesty is a problem faced by all power utilities. Finding efficient measurements for detecting fraudulent electricity consumption has been an active research area in recent years. This paper presents a new approach towards Non-Technical Loss (NTL) analysis for electric utilities using a novel intelligence-based technique, Support Vector Machine (SVM). The main motivation of this study is to assist Tenaga Nasional Berhad (TNB) in Malaysia to reduce its NTLs in the distribution sector due to electricity theft. The proposed model preselects suspected customers to be inspected onsite for fraud based on irregularities and abnormal consumption behavior. This approach provides a method of data mining and involves feature extraction from historical customer consumption data. The SVM based approach uses customer load profile information to expose abnormal behavior that is known to be highly correlated with NTL activities. The result yields classification classes that are used to shortlist potential fraud suspects for onsite inspection, based on significant behavior that emerges due to irregularities in consumption. Simulation results prove the proposed method is more effective compared to the current actions taken by TNB in order to reduce NTL activities. ©2008 IEEE.
2008-01-01T00:00:00ZDetection of abnormalities and electricity theft using genetic support vector machinesNagi, J.Yap, K.S.Tiong, S.K.Ahmed, S.K.Mohammad, A.M.http://dspace.uniten.edu.my/jspui/handle/123456789/89292018-02-21T04:42:19Z2008-01-01T00:00:00ZTitle: Detection of abnormalities and electricity theft using genetic support vector machines
Authors: Nagi, J.; Yap, K.S.; Tiong, S.K.; Ahmed, S.K.; Mohammad, A.M.
Abstract: Efficient methods for detecting electricity fraud has been an active research area in recent years. This paper presents a hybrid approach towards Non-Technical Loss (NTL) analysis for electric utilities using Genetic Algorithm (GA) and Support Vector Machine (SVM). The main motivation of this study is to assist Tenaga Nasional Berhad (TNB) in Malaysia to reduce its NTLs in the distribution sector. This hybrid GA-SVM model preselects suspected customers to be inspected onsite for fraud based on abnormal consumption behavior. The proposed approach uses customer load profile information to expose abnormal behavior that is known to be highly correlated with NTL activities. GA provides an increased convergence and globally optimized SVM hyper-parameters using a combination of random and prepopulated genomes. The result of the fraud detection model yields classified classes that are used to shortlist potential fraud suspects for onsite inspection. Simulation results prove the proposed method is more effective compared to the current actions taken by TNB in order to reduce NTL activities.
2008-01-01T00:00:00ZIntelligent detection of DTMF tones using a hybrid signal processing technique with support vector machinesNagi, J.Yap, K.S.Tiong, S.K.Ahmed, S.K.Nagi, F.http://dspace.uniten.edu.my/jspui/handle/123456789/89252018-02-21T04:42:17Z2008-01-01T00:00:00ZTitle: Intelligent detection of DTMF tones using a hybrid signal processing technique with support vector machines
Authors: Nagi, J.; Yap, K.S.; Tiong, S.K.; Ahmed, S.K.; Nagi, F.
Abstract: Efficient methods for DTMF signal detection are important for developing telecommunication equipment. This paper presents a hybrid signal processing and artificial intelligence based approach for the detection of Dual-tone Multifrequency (DTMF) tones under the influence of White Gaussian Noise (WGN) and frequency variation. Key innovations include the use of a Finite Impulse Response (FIR) bandpass filter for reduction of noise from DTMF input samples, and Support Vector Machines (SVM) for intelligent classification of the detected DTMF carrier frequencies. The proposed hybrid DTMF detector scheme is based on power spectrum analysis by means of the Discrete Fourier Transform (DFT). The Goertzel's Algorithm is used to estimate the seven fundamental DTMF carrier frequencies. The tone detection scheme employs decision logic to detect valid DTMF tones from low and high DTMF frequency groups. Comparison of this hybrid DTMF tone detection model with existing DTMF detection techniques proves the merits of this proposed scheme. © 2008 IEEE.
2008-01-01T00:00:00ZDual-tone multifrequency signal detection using support vector machinesNagi, J.Tiong, S.K.Yap, K.S.Ahmed, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/89272018-02-21T04:42:18Z2008-01-01T00:00:00ZTitle: Dual-tone multifrequency signal detection using support vector machines
Authors: Nagi, J.; Tiong, S.K.; Yap, K.S.; Ahmed, S.K.
Abstract: The need for efficient detection of Dual-tone Multifrequency (DTMF) tones for developing telecommunication equipment is justifiable. This paper presents an artificial intelligence based approach for efficient detection of DTMF tones under the influence of White Gaussian Noise (WGN) and frequency variation, using Support Vector Machines (SVM). Additive WGN in the DTMF input samples is removed by filtering out unwanted frequencies. Detection of DTMF carrier frequencies from input samples employs a traditional software based approach using the power spectrum analysis of the Discrete Fourier Transform (DFT) signals. The Goertzel's Algorithm is used to estimate the seven fundamental DTMF carrier frequencies. A SVM classifier is trained using the estimated fundamental DTMF carrier frequencies, and is validated using the input samples for classification of low and high DTMF frequency groups. The tone detection scheme employs decision logic using a rule-base expert system for classification of low and high DTMF frequency groups, corresponding to valid DTMF frequency groups. Comparison of this hybrid DTMF tone detection model with existing DTMF detection techniques proves the merits of this proposed scheme. This hybrid DTMF tone detection scheme is simulated in a MATLAB environment and results from performance tests are given in this paper. © 2008 IEEE.
2008-01-01T00:00:00ZDTC-SVM based on PI torque and PI flux controllers to achieve high performance of induction motorRashag, H.F.Tan, N.M.L.Koh, S.P.Abdalla, A.N.Chong, K.H.Tiong, S.K.http://dspace.uniten.edu.my/jspui/handle/123456789/89902018-02-21T04:49:46Z2014-01-01T00:00:00ZTitle: DTC-SVM based on PI torque and PI flux controllers to achieve high performance of induction motor
Authors: Rashag, H.F.; Tan, N.M.L.; Koh, S.P.; Abdalla, A.N.; Chong, K.H.; Tiong, S.K.
Abstract: The fundamental idea of direct torque control of induction machines is investigated in order to emphasize the property produced by a given voltage vector on stator flux and torque variations. The proposed control system is based on Space Vector Modulation (SVM) of electrical machines, Improvement model reference adaptive system, real time of stator resistance and estimation of stator flux. The purpose of this control is to minimize electromagnetic torque and flux ripple and minimizing distortion of stator current. In this proposed method, PI torque and PI flux controller are designed to achieve estimated torque and flux with good tracking and fast response with reference torque and there is no steady state error. In addition, design of PI torque and PI flux controller are used to optimize voltages in d-q reference frame that applied to SVM. The simulation Results of proposed DTC-SVM have complete excellent performance in steady and transient states as compared with classical DTC-SVM. © Maxwell Scientific Organization, 2014.
2014-01-01T00:00:00ZSolving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travelAbed, I.A.Koh, S.P.Sahari, K.S.M.Tiong, S.K.Tan, N.M.L.http://dspace.uniten.edu.my/jspui/handle/123456789/89952018-02-21T04:49:47Z2014-01-01T00:00:00ZTitle: Solving the inverse kinematics for robot manipulators using modified electromagnetism-like algorithm with record to record travel
Authors: Abed, I.A.; Koh, S.P.; Sahari, K.S.M.; Tiong, S.K.; Tan, N.M.L.
Abstract: A new modification of Electromagnetism-like (EM) algorithm which incorporating the Record-to-Record Travel (RRT) local search algorithm; namely MEMR has been developed to solve the problem of Inverse Kinematics (IK) for a four Degree-of-Freedom (DOF) manipulator. The proposed method is able to generate multiple robot configurations for the IK test performed at different end effect or positions. In addition, the comparison between the proposed MEMR and Genetic Algorithm (GA) was carried out using two mathematical test functions; De Jong and Rastrigin. The tests results show that the proposed MEMR is comparable in performance to GA in terms of both convergence speed and error rate. © Maxwell Scientific Organization, 2014.
2014-01-01T00:00:00ZPath selection technique for highly transmission ratio and reliable routing in ManetJassim, H.S.Yussof, S.Tiong, S.K.Chong, K.H.Koh, S.P.http://dspace.uniten.edu.my/jspui/handle/123456789/90612018-02-21T04:53:18Z2011-01-01T00:00:00ZTitle: Path selection technique for highly transmission ratio and reliable routing in Manet
Authors: Jassim, H.S.; Yussof, S.; Tiong, S.K.; Chong, K.H.; Koh, S.P.
Abstract: Mobile ad-hoc network (MANET) is collection of wireless nodes that operates without using a centralized network infrastructure such as a base station. Since the wireless range is limited, the nodes mutually cooperate with their neighbors in order to extend the overall communication range of the network for forwarding packets. Ad-hoc On-demand Distance Vector (AODV) is one of the commonly used protocols in ad-hoc networks. AODV is a dynamic routing protocol that is able to find the shortest path from a source node to a destination node in MANET based on hop count. However, due to the nature of MANET, it is very easy to introduce malicious nodes in MANET. These malicious nodes may try to compromise the routing protocol functionality and make MANET vulnerable to security attacks which lead to unreliable routing. Therefore, security has become a primary concern in providing protected communication among nodes in MANET. In this study, we propose a Reliable Dynamic Trust-based Routing (RDTR) protocol by integrating a trust mechanism with a shortest path routing algorithm for establishing and maintaining trustworthy routes in MANET. © Asian Network for Scientific Information.
2011-01-01T00:00:00ZSpace-Charge-Limited Dark Injection (SCL DI) transient measurementsYap, B.K.Koh, S.P.Tiong, S.K.Ong, C.N.http://dspace.uniten.edu.my/jspui/handle/123456789/88112018-02-21T04:29:39Z2010-01-01T00:00:00ZTitle: Space-Charge-Limited Dark Injection (SCL DI) transient measurements
Authors: Yap, B.K.; Koh, S.P.; Tiong, S.K.; Ong, C.N.
Abstract: It is not an easy task to probe the mobility of nanoscale thin layers without using expensive and sophisticated equipments such as Time-of-flight photocurrent charge carrier mobility measurement. We present here a powerful yet cost-effective technique, namely the Space-Charge-Limited Dark Injection (SCL DI) Transient Measurement that allows us to confirm an ohmic injecting interface, to determine the mobility values of the bulk materials and to study the injection efficiency of the interfaces of the semiconductor materials. © 2010 IEEE.
2010-01-01T00:00:00ZThermal stress test for PLEDYap, B.K.Koh, S.P.Tiong, S.K.Ong, C.N.http://dspace.uniten.edu.my/jspui/handle/123456789/88102018-02-21T04:29:38Z2010-01-01T00:00:00ZTitle: Thermal stress test for PLED
Authors: Yap, B.K.; Koh, S.P.; Tiong, S.K.; Ong, C.N.
Abstract: This work presents thermal stability studies of PLEDs involving the comparison of electrical performance before and after thermal treatment. Two cycles of continuous thermal stress test from room temperature to 100 deg Celsius did not significantly affect the total photoluminescence intensity from the light-emitting polymer in the PLED suggesting that the layer of light-emitting polymer is intact. However, the rapid degradation of the electrical performance of the PLED right after the first cycle of thermal stress test suggests that the electrodes have degraded hence hindering charge injection into the polymeric layer. © 2010 IEEE.
2010-01-01T00:00:00ZAn automated gravimetric & PWM based fluid dispensing system with GA parameter fine tuningSim, E.Y.S.Koh, S.P.Tiong, S.K.Yap, B.K.http://dspace.uniten.edu.my/jspui/handle/123456789/88122018-02-21T04:29:39Z2009-01-01T00:00:00ZTitle: An automated gravimetric & PWM based fluid dispensing system with GA parameter fine tuning
Authors: Sim, E.Y.S.; Koh, S.P.; Tiong, S.K.; Yap, B.K.
Abstract: In this paper we present a gravimetric and Pulse Width Modulation (PWM) based fluid dispensing technique for a maximum dispense batch of 30kg. In addition, a Genetic Algorithm (GA) Parameter Fine Tuning technique is presented as well. Based on the combination of both techniques, the system is able to dispense up to 50 samples with an accuracy of +/- 2g with the dispensing speed varies between 50 seconds to 60 seconds for a 5.2kg batch within one dispense valve. The reported dispensing technique is based on PWM technique in the dispensing sequence and GA technique in the parameter fine tuning. This technique could overcome limitations of the volumetric dispensing and manual parameter tuning presently applied in the coatings industry. The fast and accurate system which is modularly built out of individual dispense valve is able to handle different fluids with varying viscosity. The working principles of the system as well as its accuracy results are presented. ©2009 IEEE.
2009-01-01T00:00:00ZA hybrid genetic algorithm and linear regression for prediction of NOx emission in power generation plantBunyamin, M.A.Yap, K.S.Aziz, N.L.A.A.Tiong, S.K.Wong, S.Y.Kamal, M.F.http://dspace.uniten.edu.my/jspui/handle/123456789/89032018-02-21T04:42:00Z2013-01-01T00:00:00ZTitle: A hybrid genetic algorithm and linear regression for prediction of NOx emission in power generation plant
Authors: Bunyamin, M.A.; Yap, K.S.; Aziz, N.L.A.A.; Tiong, S.K.; Wong, S.Y.; Kamal, M.F.
Abstract: This paper presents a new approach of gas emission estimation in power generation plant using a hybrid Genetic Algorithm (GA) and Linear Regression (LR) (denoted as GA-LR). The LR is one of the approaches that model the relationship between an output dependant variable, y, with one or more explanatory variables or inputs which denoted as x. It is able to estimate unknown model parameters from inputs data. On the other hand, GA is used to search for the optimal solution until specific criteria is met causing termination. These results include providing good solutions as compared to one optimal solution for complex problems. Thus, GA is widely used as feature selection. By combining the LR and GA (GA-LR), this new technique is able to select the most important input features as well as giving more accurate prediction by minimizing the prediction errors. This new technique is able to produce more consistent of gas emission estimation, which may help in reducing population to the environment. In this paper, the study's interest is focused on nitrous oxides (NOx) prediction. The results of the experiment are encouraging. © Published under licence by IOP Publishing Ltd.
2013-01-01T00:00:00Z