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Über dieses Buch

The proceeding is a collection of research papers presented, at the 9th International Conference on Robotics, Vision, Signal Processing & Power Applications (ROVISP 2016), by researchers, scientists, engineers, academicians as well as industrial professionals from all around the globe to present their research results and development activities for oral or poster presentations. The topics of interest are as follows but are not limited to:

• Robotics, Control, Mechatronics and Automation
• Vision, Image, and Signal Processing
• Artificial Intelligence and Computer Applications
• Electronic Design and Applications
• Telecommunication Systems and Applications
• Power System and Industrial Applications
• Engineering Education

Inhaltsverzeichnis

Frontmatter

Electronic Design and Applications

Frontmatter

A Fast Transient Voltage Regulator Design with All Ceramic Output Capacitor for Mobile Microprocessors

The need to have fast transient response of the voltage regulator is driven by the increasing current slew rate of the mobile microprocessor. Hence, optimizing the switching frequency of the voltage regulator becomes an important step to achieve a balance between preserving the efficiency of the voltage regulator and improving the transient response. Besides, output capacitor solution with multilayer ceramic capacitor has also become more popular due to its small size and cheap cost. A fast transient voltage regulator with all ceramic output capacitors for mobile microprocessor is proposed in this study. The outcome of the study shows that the voltage regulator designed is stable with the proposed type and number of multi-layer ceramic capacitors. More importantly, the actual transient results correlate well with the simulation results in which minimal transient droop and overshoot are observed with a dynamic current load step with a slew rate of 10.5 A/1 µs.

C. H. Lee, N. S. Ahmad

Autonomous Agent for Universal Verification Methodology Testbench of Hard Memory Controller

Pre-silicon verification process is important in an application having integrated chip design cycle. It is considered one of the biggest bottle-neck in modern day design projects. This paper intends to describe a testbench architecture that will improve verification efficiency and productivity for a Hard Memory Controller’s Sideband verification from the perspective of the test writer. The testbench architecture described by Universal Verification Methodology is reused, adapted and improved to allow higher level of automation within the testbench. The implemented autonomous agent is analyzed and compared against the regular agent for its efficiency in terms of lines of code need to be written by the test writer. The result obtained shows that the autonomous agent implemented in the architecture reduces the test writer’s burden by at least 60 % and up to 78 %.

R. Logeish Raj, Rosmiwati Mohd-Mokhtar

Performance Comparison of the Improved Power-Throughput AES and Blowfish Algorithms on FPGA

The demand for wireless broadband access through mobile devices has increased impressively causing wireless security to be a very serious concern. Most of wireless communication standards implement an advanced encryption standard (AES) algorithm for protection against various classes of wireless attack such as interception, fabrication, modification and reply attacks. However, the AES is a complex algorithm that consumes more memory, time, and battery power. In this paper, the performance of the proposed AES and Blowfish algorithms with improved power-throughput are analysed and compared using Virtex6 field programmable gate array (FPGA) in terms of their architecture, throughput and power consumption. The results show that the proposed Blowfish has reduced slices usage and power consumption by 1 and 6 % respectively, and increased the throughput by 36 %.

R. Ahmad, W. Ismail

Development of At-speed Interconnect Test to Capture Marginal Open Defect on FPGA

This paper highlights the development of FPGA interconnect at-speed test to capture marginal open defect on Altera® Stratix V devices. The need for at-speed test was due to the increasing number of marginal open defects, resulting from manufacturing process complexity anticipated on nanometer (nm) scale IC fabrication process. Towards the final implementation, there are few unique design implemented in order to generate the at-speed clocks and the pipelined scan enable signals to support Launch on Shift (LOS) method. Meanwhile, the ability to test the interconnect on at-speed frequency required new routing tool control variables to limit the interconnect path lengths and device power consumption. The LOS test patterns used in this research managed to cover up to 81 % of the overall routing resources for marginal open defect effectively. Furthermore, the test was successfully implemented at frequencies up to 400 MHz and proven to be sensitive to routing delay to capture marginal open defects.

Fahmy Hafriz bin Mohamed Sultan, Zuraini binti Dahari, Yien Yien Koh, Neil Da Cunha, Jia Tian Ng

A Low Power Comparator Design for Analog-to-Digital Converter Using MTSCStack and DTTS Techniques

This paper presents a low power comparator using Multi Threshold Super Cut-off Stack (MTSCStack) and Dual Threshold Transistor Stacking (DTTS) techniques using a 130 nm CMOS process technology. MTSCStack is proposed in order to decrease the leakage power in active mode and retaining the logic state of the comparator during the idle state. On the other hand, DTSS is proposed to decrease the leakage current with less impact on the delay. Based on the results, the total power consumption especially dynamic power has been reduced significantly by decreasing the VDD of the comparator. The static power and dynamic power of the post-layout proposed comparator is 797 pW and 17.55 µW respectively with delay of 1.08 ns.

Pragash Mayar Krishnan, Mohd Tafir Mustaffa

Testing of Embedded SRAMs Using Parasitic Extraction Method

The limitation with the existing testing techniques is, if the test does not consider all the aspects of SRAM parameters, including parasitic memory effect, then it will result as an incomplete test. This paper presents a new parasitic extraction testing method for embedded SRAMs, employing defect-induced layout. The defect injection in a circuit is due to an open/short between wires, or missing contacts etc. In this work, only node-to-node short defects are considered. Our test results proved that using parasitic extraction method existing faults as well as undefined faults could be detected. The existing faults identified are Stuck At Fault, (SAF), Undefined Read Fault (URF), Read Destructive Fault (RDF), Undefined Write Fault (UWF), Random Read Fault (RRF), Incorrect Read Fault (IRF), and No Access Fault (NAF). The undefined faults identified are Bit-Line Delay Fault (BDF), Initialization Order Fault (IOF), Un Stabilized Write Fault (USWF), Un Stabilized Read Fault (USRF), and Write Before Access Fault (WBAF). In addition, the complete fault model dictionary is also an outcome of this work.

Muddapu Parvathi, K. Satya Prasad, N. Vasantha

A New Pixel Readout Circuit for X-Ray Image Sensor

A new high speed Complementary Metal Oxide Semiconductor (CMOS) pixel readout circuitry consuming a small area is proposed. The whole schematic is designed using Silterra 0.18 $$\mu $$μm CMOS technology and consists of 12 small-sized MOSFETs that are one-third smaller than other solutions. The time taken to capture an image of the inner body is better than that in the literature, although the same input current is used. Simulation result shows that at the minimum input current of 3 nA, the image for the three pixels at the same row can be obtained clearly at every clock cycle.

Nuha Binti A. Rhaffor, Ruhaifi Bin Abdullah Zawawi, Shukri Bin Korakkottil Kunhi Mohd, Asrulnizam Bin Abd Manaf, Othman Bin Sidek

Impact of Internal Capacitance and Resistance to the Noise Parameter Performance

This paper reports preliminary investigation of internal resistance and capacitance influence to the characterized noise parameter performance. Device Under Test (DUT) for this project is fabricated using 0.13 $$\upmu $$μm process technology. The observation is performed by looking directly at the measurement results of scattering parameter and noise parameter. All uncertainties related to the measurement have been removed by the means of calibration and deembedding. Data for the internal resistance and capacitance are extracted from the scattering parameter measurement. For comparison, the measurements were conducted at two sets of gate voltage (Vg) biasing, assuming noise levels are proportional to the amount of voltage stimulated. As for the result, it is found that the lower internal resistances will result in lower R$$_n$$n and NFmin.

S. Korakkottil Kunhi Mohd, Norlaili Mohd Noh, Awatif Hashim, Asmaa Nur Aqilah Zainal Badri, Yusman Mohd Yusof, N. Rhafor, R. Abdullah Zawawi, Mohd Tafir Mustaffa, Asrulnizam Abd Manaf

Key Policy-Attribute Based Fully Homomorphic Encryption (KP-ABFHE) Scheme for Securing Cloud Application in Multi-users Environment

Recently, cloud technologies has become a cost-effective data solution among the small and medium-sized enterprises (SMEs). However, there is a raising concern on its security. This paper proposed the Key Policy-Attribute Based Fully Homomorphic Encryption (KP-ABFHE) scheme for providing an end-to end data protection in multi-users cloud environments. The proposed KP-ABFHE scheme is able to perform the computation while providing fine-grained access on the encrypted data. The proposed scheme is able to handle a monotonic access structure over a set of authorized attributes, without sacrificing the computation capabilities of homomorphic encryption. In addition, this paper proves that the proposed scheme is secure under a selective-set model with the hardness of Decision Ring-LWE$${_{d,q, \chi } }$$d,q,χ problem.

Soo Fun Tan, Azman Samsudin

Numerical Computations and Optimizations

Frontmatter

Study of Eddy Current Density Distribution in a Contactless Breast Cancer Detection Mechanism Using Magnetic Induction Spectroscopy

Breast cancer is a throbbing disease that no longer needs an introduction. This is especially true among women due to their unique breast structure that naturally has more breast tissues compared to that of man’s. It is been forecasted that in 2015, a minimum of 60290 new cases of breast cancer will be reported. The goal of this study is to analytically evaluate the changes in the induced Eddy current densities as a function of di-electrical properties of the breast tissue with respect to tumor positioning as well as its size. This is achieved by running numerical simulations on the proposed mechanism of magnetic induction to detect tumors among healthy breast tissue via a 2D breast model configuration. The analytical results presented in this article, proved that the multi frequency magnetic induction principle is viable in detecting the breast lesions as small as 0.2 cm non-invasively through the distributions of the induced Eddy current density. While important pattern of the induced current were reflected when the tumors are located at the far ends of the breast diameter. The minimum results computational time with the proposed system is 10 s.

Gowry Balasena, Shahriman Abu Bakar, Zulkarnay Zakaria, Ryojun Ikeura, Zuradzman Mohamad Razlan, Hazry Desa, Wan Khairunizam Wan Ahmad, Cheng Ee Meng, Mohd Afendi Rojan

Improving the Reference Impedance for Fast S-Parameter Convolution via an Analytical Method

In this work, an analytical method to calculate an improved reference impedance to reduce the computational cost in a fast S-parameter convolution method is presented. The method is based on the definitions of S-parameters and is originally used to calculate the approximate characteristic impedances of transmission lines with modified ground structures. Test cases show that the developed method improves the overall computational cost by roughly 29–65 % with only a small computational overhead.

Mohd Ridzuan Khairulzaman, Patrick Goh

Optimal Chiller Loading Using Improved Particle Swarm Optimization

Reducing energy consumption is one of the most important for optimal electric-driven chiller operation. Therefore, even small reduction in power consumption will achieve significant energy savings. This paper adopts improved particle swarm optimization (IPSO), which is aiming to reduce energy consumption, and improve the performance of chillers. The method has been validated by real case study, and the results have demonstrated the effectiveness for saving energy and kept the cooling demand at satisfactory level.

Perumal Nallagownden, Elnazeer Ali Hamid Abdalla, Nursyarizal Mohd Nor, Mohd Fakhizan Romlie

Artificial Intelligence and Computer Applications

Frontmatter

A Dynamic Scatter Search Algorithm for Solving Traveling Salesman Problem

Scatter Search (SS) is a population-based evolutionary metaheuristic algorithm that selects solutions from a specific memory called a reference set (RefSet) to produce other diverse solutions. In this work, a dynamic SS algorithm is proposed to solve the symmetric traveling salesman problem (TSP). To improve the performance of SS, a dynamic RefSet update and a dynamic population update are proposed. To test the performance of the proposed algorithm, computational experiments are carried out on the basis of the benchmark instances of the problem. The computational results show that the performance of the proposed algorithm is effective in solving the TSP.

Aymen Jalil Abdulelah, Khalid Shaker, Ali Makki Sagheer, Hamid A. Jalab

Investigation on MLP Artificial Neural Network Using FPGA for Autonomous Cart Follower System

The future of the autonomous cart follower system will be equipped with lots of sensory data, due to the ever lower cost of sensory devices. This provides design challenge on handling large data and firmware complexity. This paper investigates an alternative approach of running the autonomous cart follower system on neural network model using Field Programmable Gates Array (FPGA). A microcontroller based autonomous cart follower system is modified to use the FPGA board and implemented via the System on Chip (SOC) approach. The neural network model is trained off line then implemented as software code in the SOC. By observation the firmware footprint of the neural network model remains small size regardless of the neural network size. The result shows that with 40 % more additional resource utilization, the overall system improvement of 27 times is achieved with the usage of hardware acceleration block in SOC compared to SOC without hardware acceleration.

Liew Yeong Tat, S. S. N. Alhady, W. A. F. W. Othman, Wan Rahiman

Phishing Webpage Detection Using Weighted URL Tokens for Identity Keywords Retrieval

Phishing is an online identity theft that has threatened Internet users for more than a decade. This paper proposes an anti-phishing technique based on a weighted URL tokens system, which extracts identity keywords from a query webpage. Using the identity keywords as search terms, a search engine is invoked to pinpoint the target domain name, which can be used to determine the legitimacy of the query webpage. Experiments were conducted over 1000 datasets, where 99.20 % true positives and 92.20 % true negatives were achieved. Results suggest that the proposed system can detect phishing webpages effectively without using conventional language-dependent keywords extraction algorithms.

Choon Lin Tan, Kang Leng Chiew, San Nah Sze

An Analysis of Heterogeneous Swarm Evacuation Model

In an emergency situation, members of a crowd often exhibit unpredictable behavior which can lead to major catastrophes if not well managed. The focus of this work is to analyze the crowd dynamics of heterogeneous agents, at differing densities, within an enclosed arena. Each individual reacts differently to a panic, based on diverse factors like physical contact, emotion, attraction, sights and many others. It is the combination of these individual behaviors that ultimately affects crowd behavior. When a panic occurs, the motivation of each agent is to leave the arena as soon as possible by obeying the flocking rule, the follower rule, and obstacle avoidance rule. The analysis of this work focuses on evacuation time and response rate to clear the arena under the influence of type of agent, and crowd density. Result shows that as the percentage of agents with greater knowledge of the arena increases, the evacuation time and response rate are improving. Secondly, as the the crowd density increases, the response rate to clear the arena is getting quicker, however the average evacuation time is getting slower.

Siti Juliana Abu-Bakar, W. A. F. W. Othman, S. S. N. Alhady

STCM: Secured Trust-Based Communication Method in Vulnerable Mobile Adhoc Network

Mobile Adhoc network is shrouded with various issues where majority of the problems encircle around routing and security issues. The root cause of such unsolved issues is dynamic topology and decentralized architecture. A closer look into the existing literatures shows that cryptography is the frequently used technique to ensure security in communication of mobile Adhoc network; however, there are associated issues with cryptographic implementation in security. Hence, this paper introduces a scheme based on trust factor which is less recursive and less computationally complex scheme as compared to conventional cryptographic based approaches. The proposed system applies a novel design of control message that uses simple tree to maintain certificates and performs authentication of nodes based on trust factor of node with respect to identity and behavioral pattern of the mobile nodes. The outcome of the study shows better security and communication performance in comparison to frequently used routing approaches.

Burhan UI Islam Khan, Rashidah F. Olanrewaju, Asifa Mehraj Baba, Nurul Fariza Zulkarnain, Sajad Ahmad Lone

Dengue Incidence Prediction Using Model Variables with Registered Case Feedback

This study discussed building of localized dengue incidence prediction models for districts of Selangor. System identification with Linear Least Square estimation method is used to build a number of model orders with varied lag-time and the most accurate model is selected for each district. Model accuracy is measured using Mean Square Error (MSE) value, with smaller MSE value, represents better accuracy. The flow of study is started with identification of significant weather variables. It was found that all three weather variables namely mean temperature, relative humidity and rainfall are significant predictors. Further inclusion of dengue incidences feedback data into the model was found to enhance the model accuracy. Model accuracy is further tested by comparing between single and ensemble model of few districts. Ensemble model is built using dengue prediction model of its district together with its neighbouring districts, and was found to be better predictor in two out three districts. Therefore, it was concluded that ensemble models predict better in some cases, and single models are better in other cases, depending on rate of human movement between neighbouring districts.

Loshini Thiruchelvam, Vijanth S. Asirvadam, Sarat C. Dass, Hanita Daud, Balvinder Singh Gill

Vision, Image and Signal Processing

Frontmatter

Improved Time-Domain Threshold Determination for Sparse Channel Estimation in OFDM System

Channel estimation is one of the most essential requirements in Orthogonal Frequency Division Multiplexing (OFDM) system and its exactness severely impacts the performance of the entire system. The most significant tap (MST) selection approach requires prior knowledge of channel statistics which increases complexity and a reduced spectral efficiency. Therefore, in order to tackle the approach of sparse channel estimation in OFDM systems, an improved time domain threshold (ITDT) for sparse channel estimation is thus proposed. The proposed ITDT aims at achieving an improved channel estimation performance with no prior knowledge of channel state information and noise standard deviation. At the start, an initial channel impulse response is obtained by Least Square (LS) approach. Next, a novel ITDT is proposed to obtain the estimated coefficient of noise by extracting the non-zero channel taps. Simulation results indicate a better normalized mean square error (NMSE) of 20-dB gain for a same NMSE for the proposed ITDT compare to the non-sparse LS time domain estimator.

Anthony Ngozichukwuka Uwaechia, Nor Muzlifah Mahyuddin

User Specific Weights Based on Score Distance and EER for Weighted Sum Rule Fusion

In weighted sum rule fusion, proper weights assignment for different biometric sources is very important. The effective weights assignment procedure based on individual score performance is the vital key in adaptive weighted sum fusion. In this paper, an adaptive user specific weighted sum based on score distance is devised to determine optimal weights. It integrates the performance of the biometric source represented by its Equal Error Rate (EER) and score distance in weights estimation procedure. Although the designated weighted sum fusion requires less setting and less exhaustive search of fusion parameters, it can obtain better performance than previous approaches. The proposed technique outperforms the existing user specific weighted fusion schemes in all experiments by consistently achieves a minimum EER value.

Nordiana Binti Mukahar, Haryati Binti Jaafar, Bakhtiar Affendi Bin Rosdi

Optical Setup for Solar Wafer Edge Chip Inspection

Limitations of typical camera orientations used to image solar wafer edge chipping by existing systems are demonstrated. A new design with multi-angle light source and a camera set-up which would enable the top surface and the side of a wafer to be viewed simultaneously is proposed. The capability of the new design is demonstrated and it was found that the proposed set-up is able to overcome existing limitations and obtain images that show good contrast between the defective area and its background. This would simplify the requirements for image processing for automated detection systems.

Thai Li Lim, Teow Wee Teo, Mohd Zaid Abdullah

Automatic Detection and Counting of Circular and Rectangular Steel Bars

The steel industry heavily relies on manual labor and the use of photoelectric sensors and complex counting machines to count steel bars. In the last decade, research on the automatic detection and counting of steel bars by using image processing and computer vision techniques have seen much progress. Nevertheless, most of past research focused mainly on circular shaped steel bars from a direct frontal camera angle. In this paper, we propose a method that is adaptable to both circular and rectangular shaped steel bars, and robust towards different camera angles and lighting intensity. The captured digital image first undergoes an essential pre-processing stage followed by edge detection which extracts the steel bar edges. For circular shaped steel bars, we apply Hough Transform followed by a post-process while the rectangular ones can be accurately found based on a series of morphological operations. Experiments conducted on a variety of challenging conditions demonstrate the capability of our approach to a good measure of success.

Muhammad Faiz Ghazali, Lai-Kuan Wong, John See

Comparison of Matching Methods for Copy-Move Image Forgery Detection

Copy-Move is one of the most common image forgery types, where a region of an image is copied and pasted into another location of the same image. Such a forgery is simple to achieve but hard to be detected as the pasted region shares the same characteristics with the image. Although plenty of algorithms have been proposed to tackle the copy-move detection problem, those algorithms differ in two things; matching method and type of features. In this paper, we focus on analyzing and comparing four matching methods in terms of accuracy and robustness against different image processing operations. Such analysis and comparison provide indispensable information for the design of new accurate and reliable copy-move detection techniques.

Osamah M. Al-Qershi, Bee Ee Khoo

Business Card Reader with Augmented Reality Engine Integration

Business cards are widely in use these days as formal greetings by the business professionals to make collaborations with talents of another company and their clients. The existing paper-based business cards can hardly contain too much information and the font sizes are rather tiny, causes inconvenience to individuals who suffer from vision defects, straining their eyes while accessing the information from the cards. Along with the significant growth of usage in mobile devices, this project intended to develop a Business Card Application Reader (BCAR) to provide the essential functionalities to maximize the usage of the information on the business cards. Applying the concept of augmented reality technology integrated with Vuforia library, the application is further enhanced to retrieve the business card information with over 96 % of accuracy using the image recognition technique. The application also promotes interactivity and provides new marketing campaign solution for businesses.

Vincent Hing, Hee Kooi Khoo

Gait Silhouette Extraction from Videos Containing Illumination Variates

We present a heuristic method to automatically adjust pixel intensity per frame from video by analyzing its colour type and level of brightness before initiating silhouette extraction phase. As this is performed at the pre-processing phase, our proposed method aims to show that it is an improvement or solution for videos containing inconsistency of illumination compared to normal background subtraction. We are introducing two modules; a prior processing module and an illumination modeling module. The prior processing module consists of resizing and smoothing operations on related frame in order to accommodate the subsequent module. The illumination modeling module manipulates pixel values in each frame to improve silhouette extraction for a video containing inconsistency of illumination. This proposed method is tested on 1072 videos including videos from an external KTH database.

Amalina Ibrahim, Wan-Noorshahida Mohd-Isa, Chiung-Ching Ho

Leveraging Textural Features for Recognizing Actions in Low Quality Videos

Human action recognition is a well researched problem, which is considerably more challenging when video quality is poor. In this paper, we investigate human action recognition in low quality videos by leveraging the robustness of textural features to better characterize actions, instead of relying on shape and motion features may fail under noisy conditions. To accommodate videos, texture descriptors are extended to three orthogonal planes (TOP) to extract spatio-temporal features. Extensive experiments were conducted on low quality versions of the KTH and HMDB51 datasets to evaluate the performance of our proposed approaches against standard baselines. Experimental results and further analysis demonstrated the usefulness of textural features in improving the capability of recognizing human actions from low quality videos.

Saimunur Rahman, John See, Chiung Ching Ho

Moiré Fringe Segmentation Using Fuzzy Inference System

The analysis of geometric moiré patterns is always carried out using image processing techniques and computational methods. Good segmentation of moiré fringes is desirable to reduce the uncertainty in moiré pattern analysis. In this work, a moiré fringes segmentation approach based on a fuzzy inference system (FIS) is proposed. Feature selection based on amplitude parameters and the construction of the FIS for the segmentation are described. An average recognition rate of 81.17 % is recorded for moiré fringe detection using FIS. Qualitative comparison of the moiré patterns before and after segmentation is made to confirm the applicability of the FIS-based segmentation approach.

Wing Hon Woo, Kin Sam Yen

Macroalgae Recognition Based on Histogram Oriented Gradient

The distribution of the marine algae is an important indication of the biodiversity changes in the aquatic ecosystem which algae biologist normally monitors. One of the most prominent instances is the monitoring of the invasive alga, e.g. Caulerpa taxifolia, through conducting regular surveys. It usually involves highly trained algae biologist to annotate the obtained video in order to detect the location where the alga would be likely present within survey area. This may constitute to a lengthy and demanding task which could be prone to observer-induced error. Hence, a framework is proposed herein to automate the analysis of underwater image to deduce if it contains the targeted alga, which is Caulerpa taxifolia. The framework employed HOG feature descriptor for object detection. Its efficiency and reliable was verified by the experiments using our consolidated database.

Ching Soon Tan, Phooi Yee Lau, Tang Jung Low

Efficiency Improvement in the Extraction of Histogram Oriented Gradient Feature for Human Detection Using Selective Histogram Bins and PCA

Histogram of Oriented Gradient (HOG) feature which was originally proposed by Dalal and Triggs is widely used in vision-based human detection. However, HOG feature extraction method produced a large feature pool which is computationally intensive and very time consuming, causing it not so suitable for real time application. This paper proposed a method to reduce the HOG feature extraction time without affecting too much on its detection performance. The proposed method performs feature extraction using selective number of histogram bins. Higher number of histogram bins which can extract more detailed orientation information is applied on the regions of image that may contain human figure. The rest of the regions in the image are extracted using lower number of histogram bins. This will reduce the feature size without compromising too much on the performance. To further reduce the feature size, Principal Component Analysis (PCA) is used to rank the features and select only the representative features. A linear SVM classifier is used to evaluate the performance of the proposed method. Experiment was conducted using the INRIA human dataset. The test results showed that the proposed method is able to reduce the feature extraction time by 2.6 times compared to the original HOG and 7 times compared to the LBP method while providing comparable detection performance.

Chi Qin Lai, Soo Siang Teoh

Head Pose Estimation from Undistorted Wide Field of View (WFoV) Kinect for Socially Acceptable Wheelchair

Socially acceptable wheelchairs require information about human location and pose to generate a motion that is safe and comfortable to the people around. A WFoV Kinect camera is one of the prominent sensors to obtain such information from a wide coverage of distant targets. However, the task is challenging since the expanded RGB and depth images suffers from distortion, and the head detection were far less than perfect. In this paper, we propose an empirical framework that can alleviate the mentioned problem using laser assisted undistortion strategy and depth based segmentation procedure. Initially, Kinect RGB and depth images are corrected using an inverse radial distortion model. Next, the depth data is rectified using a neural network filter based on laser-assisted training. Following that, possible human regions are validated by employing geometrical depth features. The verified depth regions are further processed in its corresponding RGB location, to determine plausible head regions using Haar-like features with the Adaboost classifier. Finally, the obtained head regions are fed to the pose estimation stage that constructed using boosted-based particle filter. Experimental results demonstrate the feasibility of the proposed approach.

Razali Tomari, Wan Nurshazwani Wan Zakaria, Rafidah Ngadengon

Density-Based Denoising of Point Cloud

Point cloud source data for surface reconstruction is usually contaminated with noise and outliers. To overcome this deficiency, a density-based point cloud denoising method is presented to remove outliers and noisy points. First, particle-swam optimization technique is employed for automatically approximating optimal bandwidth of multivariate kernel density estimation to ensure the robust performance of density estimation. Then, mean-shift based clustering technique is used to remove outliers through a thresholding scheme. After removing outliers from the point cloud, bilateral mesh filtering is applied to smooth the remaining points. The experimental results show that this approach, comparably, is robust and efficient.

Faisal Zaman, Ya Ping Wong, Boon Yian Ng

Classification of Four Class Motor Imagery for Brain Computer Interface

In this paper, four class motor imagery classification has been studied for brain computer interface. Feature investigations were conducted on the Enobio device, firstly with all 8 channels (F3, F4, T7, C3, C4, Cz, T8 and Pz) and subsequently with 3 selected channels (C4 left hand, C3 right hand, C3 and C4 both hand and Cz both feet) in alpha and beta rhythm in order to establish the active networks. Five volunteers were participated, the volunteers were instructed to perform motor imagery tasks, such as to imagine the opening and closing of the left and right hand, both hands, and both feet movement. Electroencephalogram (EEG) data were collected and offline signals processing were performed. Discrete wavelet transform (DWT) was used for feature extraction, while difference classifications methods such as multilayer perceptron (MLP), RBFNetwork, and K-Nearest Neighbors (KNN) were implemented. Best classification of MLP over KNN and RBFNetwork was noticed, whereas the highest accuracy was achieved at sym8 wavelet using DWT based feature extraction. On average over the subjects the selected channel accuracies were in the range of 86.61 %. Whereas for all the channels, accuracies were in range of 78.37 %. The study has shown that the classification accuracy can significantly improve by using specific channels for the EEG classification rather than using all EEG channels a time.

Eltaf Abdalsalam, Mohd Zuki Yusoff, Nidal Kamel, Aamir Saeed Malik, Dalia Mahmoud

Detection of Oxygen Precipitate Dark Rings in Solar Cell Luminescence Using Gray Level Co-occurrence Matrix

The presence of dark swirls or rings in luminescence image of a solar cell is usually caused by oxygen precipitate during fabrication of a solar cell. This is not desirable as it could cause a drop in efficiency of the cell. An application of gray level co-occurrence matrix (GLCM) is presented to detect such dark swirls or rings in both photoluminescence (PL) and electroluminescence (EL) images. It was found that the energy values calculated from a GLCM has a good separation between defective and non-defective images. A threshold was established based on the energy values and was then used to perform classification. Experiments have shown that this method provides a good result with minimal under-rejection and over-rejection rate for both PL and EL.

Teow Wee Teo, Mohd Zaid Abdullah

Automatic Segmentation of CMRIs for LV Contour Detection

Research on detecting, recognising and interpreting cardiovascular magnetic resonance images (CMRIs) has started since the 1980s. Time consuming and the need of expert evaluation are the key problems in the manual tracing efforts of CMRIs in a routine investigation. CMRIs manual tracing is also dependent on image quality, and there is no one-size-fits-all MRI setting for an optimum image result. In this paper, we present an approach using 2-Standard Division (2-SD) correlation along with the Sum of Absolute Difference technique and Otsu Watershed to automatically detect the left ventricle (LV) wall and blood pool in the effort to automatically assist the assessment of cardiac function. We test the approach using the Sunnybrook Cardiac Data, a standard benchmark dataset. The results shown that the proposed method had improved the automatic detection of the epicardium and endocardium.

Amjad Khan, D. N. F. Awang Iskandar, Hamimah Ujir, Wang Yin Chai

Enhancement of Cell Visibility and Contrast for Fluorescence Microscope Images by Subjective and Objective Analysis of Several Visual Aspects

Automated detection and identification of abnormal cells in the human body is a critical application for medical image computing. Enhancement and de-noising of images remain challenging tasks and imperative steps for image analysis algorithms. Indeed, due to its early role in the process, the results of advanced operators for feature extraction will highly depend on the quality of enhanced image produced. Depending on the presence of different noise types, particular algorithms will respond better. This paper presents a comprehensive comparison between several linear and non-linear filters applied on fluorescence microscope images for the localization and counting of specific cancer phenotypes from mouth cell samples. The objective analysis proposed is evaluating the PSNR and Delta-SNR (the SNR to SNR measure between original images and filtered ones) for blood sample sequences taken from Cancer Research Malaysia. Thirty Fluorescence microscope images with low contrast and non-uniform illumination have been tested and analysed. Non-linear algorithms seem to show improved contrast and background removal abilities compared to linear blurring and approximating filters.

Abed Alrahman Mkayes, Nicolas Walter, Naufal M. Saad, Ibrahima Faye, Sok Ching Cheong, Kue Peng Lim

Robotics, Control, Mechatronics and Automation

Frontmatter

Stability of Discrete-Time Internal Model Control Against Several Perturbations

Internal Model Control (IMC) is a popular control approach that integrates the model of the plant into the controller. In most cases, it is common to have a mismatch between the plant and the model due to noise and disturbance. Actuator constraints may also be another source of instability or performance degradation in IMC. This has lead to the development of IMC structure to sustain its robustness against many different types of uncertainties. This note presents a stability analysis of discrete-time IMC which is subject to saturation and a bounded uncertainty. The stability is guaranteed via one of the discrete counterparts of Popov criterion, namely Jury-Lee criterion (This work was supported by Fundamental Research Grant Scheme (203/PELECT/6071267), Ministry of Education of Malaysia.).

Kevin Choo, N. S. Ahmad

Deflection Analysis of a Robotic Bed on the Applied Loads and Its Postures for a Heavy-Ion Therapeutic System

In this paper, we present two preliminary experiments, under laboratory environment, in order to determine whether or not our robotic bed needs a deflection correction function due to patient’s various weights and its postures. We measured (1) robotic arm’s deflection with various loads from 0 to 80 kg, and (2) variation of carbon bed’s deflection with various postures in which the bed is tilted by ±20° roll and pitch angles respectively. Experimental results show that the robotic arm’s deflection measured up to 2.6 mm and the variation of carbon bed’s deflection measured greater than 0.5 mm when the tilted angle was more than 15°. We, therefore, concluded that the deflection correction function is necessary for our robotic bed especially in the case of head/neck treatment in which the tilted angle is needed to be more than 15°.

Hongseok Choi, Jong-Oh Park, Seong Young Ko, Sukho Park

An Autonomous Lane-Keeping Ground Vehicle Control System for Highway Drive

In this paper, a control system for lane-keeping ground vehicle is designed. Under the assumption of highway driving condition, with an uncertain road curvature, a lane keeping vehicle control system is developed. The closed loop control system is obtained by implementing a PID (proportional, integral and derivative controller) control strategy. For a MIMO (multi-input multi-output) vehicle model, a loop of PID controllers is designed to ensure the lane keeping criteria of the vehicle is satisfied. Several simulation results have demonstrated the functionality of lane-keeping feature of the vehicle.

Ahmed Sharmin, Rahiman Wan

Performance Difference with Respect to the Number of Wheels on the Cricket Bowling Machine

Cricket is one of the sports played in Malaysia. The national team is under the supervision of the Malaysia Cricket Association (MCA). Currently, most the player training is done manually. Therefore, this study focuses on the development of the cricket bowling machine as a mean to ease the training session as well as analyzing the machine’s performance through experimental data. Two machines have been designed and fabricated to analyze the difference in performance between a single rotating wheel mechanism and two counter rotating wheel mechanism to propel the ball. The ball speed ratio is based on the linear wheel speed. As the wheel speed increases, the single-wheel ball speed ratio ranged from 47 to 50 % with a gradient of −0.0032. On the other hand, the two-wheel ball speed ratio ranged from 68 to 95 % with a gradient of −0.0245.

Fernandez Dhanaraj Davaraj, Muhamad Iqbal Nor Faizal, Muhammad Ridwan Sunandar, Anwar Hasni Abu Hassan

Comparison of Mamdani and Sugeno Fuzzy Logic Performance as Speed Controller

This paper compares the output from Mamdani-based fuzzy logic controller and Sugeno-based fuzzy logic controller in controlling speed of an Remote Controlled (RC) car. There are two inputs involved which are deviation and distance and one output which is the speed to be input to the RC car motor. Results from randomized data simulation test shows that Sugeno-based fuzzy logic controller produces desirable result in contrast to Mamdani-based fuzzy logic controller in controlling the speed of the RC car.

Izzati Saleh, S. S. N. Alhady, Wan Rahiman

Development of Swarm Robots for Disaster Mitigation Using Robotic Simulator Software

Swarm robotics come into the picture of replacing humans on life-risking jobs because of its decentralization concept, i.e. a damaged unit do not affect the entire system performance. Airborne type swarm robotics have high flexibility since they can bypass most obstacles. Swarm robotics can be utilized to scout unknown terrain, target searching or S.A.R applications. In this project, simulation to visualize the swarm quadcopters’ performance onto an assigned environment using robotic software simulator called V-REP software is presented. Robotic simulator software take account of real-life physics which increases the accuracy for simulation and retrieves reliable results from the simulation. Hence, robotic simulator software could replace real-life testing for at least initial ideas exploration to real-life situation.

Yeong Yie, Mahmud Iwan Solihin, Ang Chun Kit

An Assistive Robotic Hand Based on Human Computer Interface (HCI) and Shape Memory Alloy (SMA) Actuator

Rehabilitation and assistive robotics is an emerging field of research where researchers are trying to develop tailored made robotic devices to address the challenge of disability. This paper presents a study on feedback controlled wearable robotic hand for grasping. The proposed design is compact and sufficiently light to be used as an assistive hand. It is tendon driven and joint-less structure that has the potential to be used as an assistive device for stroke patients. The concept has been implemented for index and thumb fingers as a first prototype to enable grasping. Shape memory alloy (SMA) actuator and bias force mechanism are used for the purpose of hand’s flexion and extension. This paper describes the mechatronic design of the wearable hand, simulation, modeling, and development of the actuation unit and sensory system. Experiments of open loop controller were conducted to understand the hand characterization and grip force provided by index finger. A feedback controller (proportional controller) was implemented for this prototype with gripping force as the feedback parameter. It was observed that approximately 2.25 A current caused 4 cm displacement for SMA actuator. The maximum temperature of the SMA actuator was achieved to be 100 °C. The attainable gripping force was around 2 N for a load free finger. The conducted experiments showed promising results that encourages further development on this.

Alala Ba Hamid, Mohatashem Makhdoomi, Tanveer Saleh

Development of Rao-Blackwellized Particle Filter (RBPF) SLAM Algorithm Using Low Proximity Infrared Sensors

Simultaneous Localization and Mapping (SLAM) algorithm are often developed using accurate sensor such as laser rangefinder. However, recently more consumer-oriented robots are usually equipped with low-end sensor such as low-proximity infrared sensor due to its lower cost. This has motivated this research work to implement RBPF-SLAM algorithm using infrared sensor only. Despite of the sparseness and noisiness characteristics of infrared sensor, it is used as the only robot’s perception in the RBPF-SLAM algorithm developed. The performance of this algorithm is investigated and analyzed. The result shows a decent and satisfactory map.

Norhidayah Mohamad Yatim, Norlida Buniyamin

Trust Evaluation in a Multi-robotics System Through Direct Learning

In a mission that requires collaboration or cooperation, trust is an important social norm to ensure success. This paper presents the study of embedding the concept of trust in a multi robots system, similar to the social norm of trust between humans. The proposed framework called TD Trust enables the robots to learn and evaluate trust on other robot through experience. To achieve this, reinforcement leaning technique is used to empirically evaluate the trust between robots through observation and experience. This framework is then tested in a simulation study by comparing the performance of a system with the trust model embedded and without.

G. Rishwaraj, S. G. Ponnambalam, Chu Kiong Loo

Stabilization of Inverted Pendulum: A Multirate Output Feedback Based Discrete Time Sliding Mode Control

This paper presents the application of multirate output feedback with discrete time sliding mode control (SMC) for controlling the inverted pendulum system. The SMC are well known as completely insensitive to parameter variations and external disturbance. Normally, in order to design controller, the state feedback from the entire state variable is utilized. However not all of the state feedbacks are always available. Therefore, the concept of the multirate output feedback (MROF) in which the output state that are always available at any situation is proposed. The nominal plant model for inverted pendulum system is fourth order with additional of external disturbance. Simulation results verify the proposed controller’s performance even though nonlinearity present in the inverted pendulum system.

R. Ngadengon, Y. M. Sam, J. H. S. Osman, R. Tomari, W. N. Wan Zakaria

Stability Criteria for Classical Digital Phase-Locked Loops

A Classical Digital Phase-Locked Loop (CDPLL) is a hybrid system as it contains both analog and digital components. For a CDPLL with an XOR-gate phase detector (PD), it is useful to analyse its stability since its performance is affected by the nonlinear behavior of the PD. This paper presents the stability analysis of CDPLL in continuous and discrete-time domains. Four criteria are used, Circle and Popov for continuous-time domain, and Tsypkin and Jury-Lee for the discrete-time domain. Numerical examples are included to show the different stability margins provided by the aforementioned criteria.

Siti Juliana Abu Bakar, Nur Syazreen Ahmad

Brief Reviews: Time Synchronization Protocols in Wireless Sensor Network—Centralized Versus Distributed

Rapid developments in the areas of sensor design, information technologies, and wireless networks have caused the wireless sensor network (WSN) emerges as a key role in many fields of science and industry. Time synchronization is essential in WSN to ensure all nodes in the WSN are synchronized and coordinated. In this paper, a brief introduction of WSN is given. Then, this paper reviews the widely discussed time synchronization protocols developed in the past and compares the protocols in two group, centralized and distributed.

Yeong Chin Koo, Muhammad Nasiruddin Mahyuddin

Modeling and Adaptive Control Design for a Quadrotor

In this paper, a detailed mathematical model for a quadrotor is presented. The quadrotor dynamics is defined using matrix notation and since the dyadic notation is not used, the equation is easy to be modeled and also to be considered for controller design. Moreover, an adaptive controller is designed for a simple motion of the quadrotor including taking-off, hovering and landing. The generated model and the designed adaptive controller of an indirect scheme could be utilized as a basis for further investigations.

Ali Safaei, Muhammad Nasiruddin Mahyuddin

Telecommunications, RF, Antenna and Applications

Frontmatter

Lumped Element Equivalent Circuit Modelling for RF Energy Harvesting Antenna Array

An approximate LC lumped element equivalent circuit model antenna array for RF harvesting is presented. The array consists of two identical parallels of a resonant circuit that aimed to provide an alternative energy sources for energizing low power devices. The entire structure of spiral inductor array exhibits an aperture size of 14.3 mm × 7.0 mm at a center frequency of 956 MHz. The proposed design is fed by a 50 O microstrip line. A simple of LC lumped element equivalent model and using a magnetic frills model approach is described and to predict the characteristic of spiral antenna array. The results obtained for the resonant circuits through the circuit analysis are compared using the finite integration technique commercial solver and Agilent advanced design system. A good agreement between simulation and measurement results is successfully confirmed.

Chia Chao Kang, Mohd Fadzil Ain, Ali M. J. Zalzala, Ihsan A. Zubir

Dual-Frequency Integrated Power Dividing E-Shaped Antenna

This paper presents an E-shaped antenna design which resonates at two different frequencies, 2.4 and 2.5 GHz. The antenna exhibits three output ports and integrates a power divider function which splits the 2.4 GHz signal equally along the in-phase ports at both its side wings. In this work, Sonnet is adopted in simulating the design and the resultant return losses for all three ports indicate remarkable matching (<–10 dB) at its respective frequency of concern.

Kim Huat Yeap, Widad Ismail, Kim Ho Yeap, Soon Leng Yap

PCB Level Shielding Effectiveness Evaluation in Near Field by Using Electromagnetic 3D Scanner

Shielding always play a main role in the effort to control electromagnetic interference of an electronic device. Metal shield cans had been widely used in electronic industry to ensure the compliance of products to Electromagnetic Compatibility (EMC) standard. The rapid growth of technology evolution urges wireless electronics devices to become thinner, smaller, and faster; they are operating in higher frequency, commonly up to Giga-Hertz. These smaller form factors make the PCB layout getting more compact and the spacing between components greatly reduced. These limitations earn a drawback that high frequency nature of the signals easily coupled among traces and components. Therefore, in this paper, a near field PCB-level shielding effectiveness evaluation method of small shield cans using a 3D Electromagnetic scanner is proposed. To verify the measurement result, a reliable simulation tools, Computer Simulation Technology (CST) Microwave Studio was applied. From the simulation and real measurement, decent and accurate results were obtained.

Yih Jian Chuah, Mohd Tafir Mustaffa

Implementation of Signal Flow Graph Rules Analysis on Short-Open-Load-Thru Calibration Algorithm

The error correction procedures are important in VNA calibration measurement in order to achieve accurate performance. By understanding the concept of error correction, the mathematical analysis related to this feature can be applied easily in further investigation. This paper reviews a mathematical analysis of short-open-load-thru (SOLT) calibration algorithm by using signal flow graph rules. In order to understand the concept of error correction represented by signal flow graph rules, the analysis will start with one-port calibration, before proceeding to two-port calibration. Then, it can be implemented to short-open-load-thru (SOLT) calibration algorithm.

Rashidah Che Yob, Nor Muzlifah Mahyuddin, Mohd Fadzil Ain

PLL-Based Frequency Synthesizer Analysis and Simulation

Phase-locked loop (PLL) forms the basis of frequency synthesizers which have been widely used in radio communications. One of the main building blocks in a frequency synthesizer is the digital divider placed in the feedback path which determines the scaling factor of the synthesizer. In order to synthesize a high frequency output, a higher scaling factor is required and this also demands for a higher loop gain to maintain its performance. However, as the PLL is inherently nonlinear, the usual linear approximation method is not valid to guarantee the stability of the synthesizer in general. In this work, we present a nonlinear analysis of the frequency synthesizer which resembles a Lur’e system with a sector- and slope-bounded nonlinearity in z-domain. One of the absolute stability methods suitable for such a system, namely the Jury-Lee criterion, has been used to search for the maximum loop gain and the scaling factor for which the synthesizer remains locked. The optimization problem is formulated in terms of a linear matrix inequality (LMI) which is computationally more attractive than frequency-based conditions (This work was supported by Fundamental Research Grant Scheme (203/PELECT/6071267), Ministry of Education of Malaysia.).

Pei Ni Goh, N. S. Ahmad

A 1.8 GHz and 2.4 GHz Multiplier Design for RF Energy Harvester in Wireless Sensor Network

Nowadays, RF energy harvesting has become increasingly popular in green technology due to the high rise of the television base stations, mobile phone base stations, Wi-Fi, Bluetooth and others. Many works have been done on harvesting the RF energy. However, the RF energy available around is too small and the conversion efficiency at the multiplier part is very low. Thus in this work, the multiplier part of the RF energy harvesting circuit has been designed to change the low RF energy collected from the receiving antenna from AC to DC focusing on low RF input. Two different frequencies will be focused on 1.8 and 2.4 GHz. Dickson multipliers are designed, simulated and optimized using Advanced Design System. The final Dickson multiplier design for each frequency satisfied the requirement set to operate at a low input power with efficiency of 6.5 % (0.96 V) and 5 % (0.76 V) at 0 dBm for 1.8 GHz and 2.4 GHz respectively. This paper can be a reference for future design of 1.8 and 2.4 GHz RF energy harvesting circuit.

Ye E. Sun, Nor Muzlifah Mahyuddin

RFID Technology on Tracking and Monitoring Applications

This paper presents the impact of passive radio frequency identification (RFID) technology with Java Database Connectivity (JDBC) for the application of campus bus tracking and student monitoring. In this research, the system is developed to track USM charter buses which operate on a selected route and to monitor the number of students using a tagged bus. The system composes of 3 main mechanisms; passive RFID tags at ultra-high frequency (UHF) together with the support of a passive RFID reader and a JDBC-based back-end database system that records the detected data. The proposed system will eliminate the need for manual data recording in tracking a tagged vehicle or monitoring the passenger’s ridership pattern.

V. Priyashman, W. Ismail, J.H. Khor

Design Optimization of Split Ring Resonator Array

Split Ring Resonator (SRR) is widely used in research area due to its compactness characteristics and low implementation cost. SRR can be incorporated with microstrip line and can be tested for various purposes. This paper, will present about the wide properties of SRR in term of different size, spacing and rejection of SRR during transmission. From the result, it shows that when the size of SRR increases, the resonance frequency decreases. This is due to the inverse relationship between the SRR dimension and the resonance frequency which also involves the inductance value. Moreover, the effect on SRR separation also will be studied. As the distance separation between SRR decreases, the coupling between SRR will be increased.

Nur Ahlina Yusop, Nor Muzlifah Mahyuddin

Development of All Optical Signal Regeneration Method for 100 Gb/s Differential Phase Shift Keying Degraded Signal

In long haul communication systems signal is transmitted at extensive distance. Today, most of the systems have signal regeneration are not efficient enough to regenerate the 100 Gb/s signal for low Bit Error Rate (BER) of 10−10 at lower than −10 dBm received power with noise mitigation. In this paper, a new all-optical signal regeneration technique is demonstrated for 100 Gb/s degraded Differential Phase Shift Keying (DPSK) signal that regenerate the signal quality using matlab Simulink model. The developed technique has achieved the 10−15 BER at −15 dBm with noise (amplitude and phase) mitigation up to 90 % for degraded signal compared to existing signal regeneration that are limited to offer the BER of 10−10 at −9 dBm not more than 60 Gb/s transmission systems. The proposed technique will be helpful to improve the performance of existing signal regeneration systems in terms of BER at low power penalty.

Bhagwan Das, M. F. L. Abdullah, Nor Shahida Mohd Shah

An Improved IDCT-OFDM with Partial Transmit Sequence

Orthogonal frequency division multiplexing (OFDM) has been adopted as a standard for various high data rate wireless communication systems due to the spectral bandwidth efficiency, robustness to frequency selective fading channels, etc. However, implementation of the OFDM system entails several difficulties. One of the major drawbacks is the high peak-to-average power ratio (PAPR), which results in intercarrier interference, high out-of-band radiation, and bit error rate performance degradation, mainly due to the nonlinearity of the high power amplifier. In this paper, a new technique that implements inverse discrete cosine transform (IDCT) along with PTS concept to get an improved PAPR reduction level were introduced. Simulations are performed with QAM modulation, 64 subcarriers and variety number of partitions and admitted angle phases. A comparison between the proposed technique with OFDM, PTS, and GDCT Precoded OFDM with PTS was conducted and the simulation result shows that the proposed technique surpass all three technique in term of PAPR reduction. Furthermore, the proposed technique can reduce the maximum OFDM PAPR level to 0 dB.

A. A. A. Wahab, Adnan Haider Yusef Sa’d

Multi-hop Performance of Smart Power Meter Using Embedded Active RFID with Wireless Sensor Network

The implementation of Smart Power Meter (SPM) using embedded active RFID tag with Wireless Sensor Network (WSN) for identification and monitoring of data is presented to analyze and improve the link quality of multi-hop performance in real environment application. In the proposed system, ZigBee (IEEE 802.15.4) protocol standard with radio frequency of 2.4 GHz was embedded into a household Power Meter (PM) to obtain a higher performance in the data monitoring system. This proposed system, anti-collision algorithm is an effective method to handle and support the link quality through the single and multi-tag via multi-hop communication with several time intervals between messages sending as well. The finding indicated that the proposed SPM has successfully received massages of about 0.89 and 1.44 % higher than the standalone RFID for single and multiple tags over four hops communication respectively, with there is no difference at statistical significance level of 95 % reliability.

W. Boonsong, W. Ismail

Analysis of Hybrid Ring Coupler Double-Balanced Mixer and MMIC Double-Balanced Mixer for Ka-Band Wireless Communication Systems

This paper reports the architecture design of 26–32 GHz downconverter passive double-balanced mixers used for RF front-end circuit design. The performance of the simulated lumped hybrid-ring coupler double-balanced mixer and the monolithic microwave integrated circuit (MMIC) double-balanced mixer are going to be compared throughout this paper. Both designs are compared based on the conversion gain, intermediate frequency (IF) return loss and RF to IF signals isolation. The MMIC surface mount package is mounted in a 50 Ω test fixture which eliminates the need for wire bonding.

Mohamad Faiz Omar, Mohd Fadzil Ain, Khairul Anuar Norhassim, Arjuna Marzuki, Mohd Zaid Abdullah, Zainal Arifin Ahmad

Investigation of the DGS-CDRA Design with the Aperture Coupling Technique for Wide Band Application

In this paper, a design of wideband antenna by tuning the aperture slot parameters and using two dielectric pellets is investigated and discussed. The performance of the resonant frequencies, impedance bandwidth and radiation pattern of the DGS-CDRA (Defected Ground Structure Cylindrical Dielectric Resonator Antenna) are analyzed. The design achieved a wideband impedance bandwidth of 4.0 GHz (50.74 %) by using two slots aperture and thick substrate. Two dielectric pellets with the same type and size are coupled to a microstrip line through two rectangular slots. The slots positions are tuned along (below) microstrip line to a position where impedance bandwidth from both dielectric pellets are merged and form a wide impedance bandwidth. Subsequently, performance of the antenna is being analyzed based on the simulation results of return loss and radiation pattern. The design is fabricated and the measurement results of impedance bandwidth are compared with the simulation results.

S. M. Che Abdullah, N. M. Nor, M. A. Zakariya, S. M. Ali, H. Daud

Investigation of DGS CDRA for High Gain Applications

A single element rectangular aperture coupled cylindrical dielectric resonator antenna (CDRA) with a plane reflector is proposed. A plane reflector is integrated at the back of the proposed CDRA to provide unidirectional radiation pattern with the improvement in gain and sidelobe level. The gain of the DRA is improved by reducing the back radiation caused by the aperture coupling. The peak gain of the antenna has been enhanced about 4.3 dB from 4.7 to 9.0 dBi at 5.18 GHz. The measured impedance bandwidth achieved for the proposed DRA is 0.2 GHz for S11 < −10 dB from 5.17 to 5.37 GHz. The radiation pattern with broadside radiation and low back radiation has been obtained. The experimental and measured results show that the antenna is high gain, small in size and satisfies the basic requirements of WLAN 802.11a.

Mohd. Azman Zakariya, Syed Muzammil Ali, Zuhairi Baharudin, Muhammad Zaka Ur Rehman, Shuhaida Masni Che Abdullah, Abid Muhammad Khan, Muhammed Talha Khan

Analysis of Passive Frequency Multiplier Designs for K-Band Wireless Communication Systems

This paper reports the passive frequency multiplier designs used to obtain a pre-determined multiplies output frequency of 20 to 26 GHz in modern communication system. The performances between the simulated lumped frequency multiplier modeling design and the Monolithic Microwave Integrated Circuit (MMIC) frequency multiplier design are going to be compared throughout this paper. Both designs are analyzed based on the results of the output power frequency obtained. The MMIC frequency multiplier fabricated using Pseudomorphic High Electron Mobility Transistor (PHEMT) technology and packaged into Quad Flat No-leads (QFN) package with Surface Mount Technology (SMT) application. The commercial MMIC surface mount package is matched to 50 Ω and fully blocked.

Mohamad Faiz Omar, Mohd Fadzil Ain, Khairul Anuar Norhassim, Arjuna Marzuki, Mohd Zaid Abdullah, Zainal Arifin Ahmad

Improved Low Cost Substrate Integrated Waveguide Symmetrical Window Bandpass Filter

Substrate integrated waveguide (SIW) has been recently emerged to be a promising technology in the development of microwave and millimetre-wave field. SIW is the integration of rectangular waveguide and planar circuit, exhibiting advantages from both technologies. In this paper, the design of low cost SIW technology for bandpass filter is discussed. The design of SIW symmetrical window bandpass filter is explained in detail. 5th order 0.5 dB ripple of Chebyshev filter response is used to design SIW symmetrical window bandpass filter. The measured results shows that the fabricated prototype is able to operate within X-band frequency with passband of 8.6 to 10.6 GHz. The design procedures in obtaining width of symmetrical windows and length of SIW window cavity are shown in detail in this paper. The filter design that fulfills the specifications is fabricated on a single layer Duroid RO4003C substrate using printed circuit board (PCB) process. The simulated result and measured result are compared and analyzed. Hence, it can be concluded that the measured bandwidth of the design is operating within X-band frequency range, which at 8.6 Hz until 10.6 GHz. The average value of measured S11 has minimum of −20 dB and the average value of measured S12 has maximum of −2 dB.

M. L. Fong, M. Rafiee, H. Y. Cha, M. S. Aftanasar

Biomedical, Bioengineering and Applications

Frontmatter

Automatic Detection of Embolic Signal for Stroke Prevention

Transcranial Doppler (TCD) ultrasound is an essential tool in clinical diagnosis to determine the occurrence of embolism in stroke patients. However, it requires manual attention and the accuracy will deteriorate due to fatigue factor. Instead of depending on human observer as a gold standard to detect the emboli, this study proposes an automated emboli detection system based on three detection methods i.e. time-domain intensity, frequency-domain intensity and time-frequency intensity hybrid. Experimental studies of 240 samples of six data sets were employed. The performance evaluations of each method are measured in term of accuracy percentage and processing speed while human observation is also done as the golden standard for accuracy comparison. The best result is achieved by the time-frequency intensity hybrid method where 90.74 % of the embolic signals and 100 % of the non-embolic signals were successfully identified. The performance of this method is promising as the accuracy achieved by human observation was 87.45 and 100 % for embolic signals and non-embolic signals, respectively.

Noor Salwani Ibrahim, Ng Yan Duan, Dzati Athiar Ramli, Haryati Jaafar

Analysis of Finger Vein Feature Extraction Using Cross-Sectional Profile Approach

Finger vein identification technique has drawn much attention among scholars recently. As a result, various methods have been proposed in order to design robust identification systems. There are four important steps in executing finger vein identification techniques which are data accusation, feature extraction, pattern matching and decision of the identification. This study focuses on extraction methods by introducing repeated line tracking and maximum curvature which work based on the cross-sectional profile of the finger vein image. The experimental results revealed that these methods are feasible to be used for finger vein feature extraction.

Amir Hajian, Dzati Athiar Ramli

Computational Fluid Dynamics Simulation on Blood Velocity and Vorticity of Venous Valve Behaviour

In this work, a computational fluid dynamics (CFD) is used to analyze the effect of different opening between two valves of a normal popliteal vein. This study was focusing on the velocity and also vorticity of blood along the popliteal vein distribution. Based on the observation and analysis of the data, the different size of orifice between the first valve and second valve influencing the velocity and vorticity of the blood flow. The rotational motion of blood particle at the same spot will increasing the probability of blood accumulating which helping in development of thrombus. The effect of the irregularities in the blood flow will cause valve insufficiency that will lead to various disease related to venous vessel such as heart attack, deep vein thrombosis (DVT), pulmonary embolism (PE)and the worst is death. A series of experiment has been conducted by changing the size of valve orifice for the first and second valve along the vein distribution. The result of the CFD simulation shows a significant result of blood flow in term of velocity and vorticity.

Nur Shazilah bt Aziz, Nabilah bt Ibrahim, Kamil Abdullah, Noor Hafizzatul Izzah bt Mat Harun

Study of Vein Mechanism on Pregnancy Condition for Early Diagnosis of Deep Vein Thrombosis

In this paper, the study is conducted as an effort to provide better visualization of ‎vein mechanism properties between healthy subjects and pregnant subjects. Here, ‎it is proposed to evaluate the vessel condition for the pregnant subject ‎and comparison to the healthy subject is done. Pregnancy had been one ‎of the risk factor that contributes to the development of thrombus in the vessel ‎which called Deep Vein Thrombosis (DVT). The DVT condition usually ‎diagnosed using the ultrasound which is non-invasive, by monitoring the ‎development of thrombus in the vessel. In this study, evaluation on two important ‎parameters which are the measurement of the vessel wall displacement and also ‎the blood flow velocity in the vein was done. It is believed that these two ‎elements are crucial to construct a clinical model of Deep Vein Thrombosis ‎‎(DVT) risk factor, which constitutes an important contribution for predicting ‎probability of the development of Deep Vein Thrombosis (DVT) and help in ‎preventing this condition.

Noor Hafizzatul ‘Izzah bt Mat Harun, Nabilah bt Ibrahim, Nur Shazilah bt Aziz, ‎Wan Nurshazwani binti Wan Zakaria, Nik Farhan bin Nik Fuad‎

Sensors and Sensing Techniques

Frontmatter

Measuring Solar Ultraviolet Exposure Dose on EBT3 Film Through the Application of Visible Absorbance Spectroscopy

External Beam Therapy 3 (EBT3) film is the latest model of the EBT film that has been designed to overcome Newton’s Rings artifact and the orientation problem of film during scanned process that occur in radiotherapy procedure. The original colour of the film (light green) will become darken (dark green) depending on the cumulative energy received on the film. This paper examined the applicability of EBT3 film in measuring solar ultraviolet (UV) exposure dose. The solar UV energy obtained through conventional UV meter was correlated with the colour changes of EBT3 film. The colour changes of the films were analyzed using visible absorbance spectroscopy technique. The 5 best wavelengths (A506.77 nm, A604.68 nm, A658.17 nm, A692.99 nm, A699.83 nm) in the experiment produce calibration result with R2 = 98.5 % and RMSEC = 301.59 mJ/cm2; and predicted result with R2 = 98.3 % and RMSEP = 381.92 mJ/cm2, which mean high correlation between UV irradiance with colour changes of EBT3 film. The EBT3 film gave a good response toward UV dose with the increases in the absorbance of the film with the exposed dose. This means that the measurement of UV dose can be performed using EBT3 film.

Mohd Amirul Tajuddin, Ahmad Fairuz Omar

Robot Hand Fingertip Design Validation

Among the challenges in designing robot hand is to make it feature packed but still maintaining a compact human-hand sized without compromising its robustness. The previous work had elaborated the design process of a three-fingered robot hand until a functioning prototype is successfully produced. However, the performance of the robot hand for grasping was insufficient. This paper will discuss the enhancement in the existing design to incorporate force sensing ability with better grip-ability of the fingertip. The improved design fingertip was fabricated using rapid prototyping machine. Then, two miniature load cells were fitted into the fingertip to enable force sensing in two directions namely x-axis and z-axis. The fingertip maintains the easy-to-replace feature, improving the tip surface for better grasping and creating canal-shaped gap to have a compliant-like material effect when the fingertip is subjected to any external force. From the calibration result, it can be observed that the measured force is linearly related to the applied force in both x and z axes to prove the feasibility of the proposed design.

J. Jaafar, K. Nasir, R. L. A. Shauri

Spectrometry Evaluation of B10 Averrhoa carambola L. and Sala Mango Physical Attributes

The physical quality attributes of B10 carambola and Sala mango are normally graded based on its colour index and size (weight). For colour classification, the indexing process is conducted by trained staffs from Federal Agricultural Marketing Authority (FAMA). However, this method is highly subject to error since the evaluation is made through human visual perception. This paper presents an innovative application of visible and near infrared (NIR) spectroscopy in quantitative measurement of carambola and mango physical quality, two of the Malaysian most popular tropical fruits. For comparative analysis, the spectroscopy measurement was conducted using reflectance and interactance techniques. The best algorithm for predicting carambola and mango index has been generated by MLR + SG (reflectance: R2 = 0.934; RMSEP = 0.489) and MLR + MSC (reflectance: R2 = 0.931; RMSEP = 0.504) respectively. On the other hand, the best algorithm for predicting carambola and mango weight has been generated by MLR + SG (interactance: R2 = 0.754; RMSEP = 17.454 g) and MLR + SG (reflectance: R2 = 0.769; RMSEP = 89.122 g) respectively.

Ahmad Fairuz Omar, Ommi Kalsom Mardziah Yahaya

Power Systems, High Voltage Engineering, and Renewable Energy

Frontmatter

LLC Resonant DC-DC Converter for High Output Voltage Applications

This presents an LLC resonant DC-DC converter for high output voltage applications. The proposed converter consists of four main parts which are a full bridge (FB) inverter, a resonant tank (LLC), a high voltage transformer (HVT) and a HV bridge rectifier. The proposed converter can regulate the output voltage by narrowly varying the switching frequency. The LLC resonant circuit is utilized to retrieve the energy trapped in the leakage inductance of the transformer and to achieve the zero voltage switching (ZVS) feature. The resonant circuit also increases the conversion efficiency. A low power prototype of proposed converter is implemented to verify its benefits. The experimental results from the laboratory prototype are given to validate the operation of converter.

Nor Azura Samsudin, Shahid Iqbal, Soib Taib

Incremental Unsupervised Learning Algorithm for Power Fluctuation Event Detection in PV Grid-Tied Systems

Obstacles for solar photovoltaic (PV) system to be a reliable energy source is its intermittent and stochastic output power. The randomness output power could trigger power fluctuation event. Subsequently, more power quality issues such as frequency fluctuation, voltage variation and harmonic distortion could happen. Thus, this paper introduces a Self-Organizing Incremental Neural Network (SOINN) to predict the output power and subsequently detect the power fluctuation events in order to enhance the reliability of a PV grid-tied system. The SOINN is developed from the growing neural gas and competitive hebbian learning. It could be trained without predefined the structure of the network. To train the SOINN, input data to the PV system such as irradiance and temperature are used. The trained SOINN will be compared with the Self-Organizing Map (SOM) network. Results show that the SOINN prediction engine achieves an accuracy of 100 % in identifying power fluctuation event through predicted output power.

Ken Weng Kow, Yee Wan Wong, Rajparthiban Kumar Rajkumar, Rajprasad Kumar Rajkumar, Dino Isa

Effect of Nano-Alumina on Electric Tree Growth in SiR Nanocomposites

Nowadays, nano technology is one of the new approaches used in enhancing the strength of polymeric insulating material. This paper presents the process of electric tree growth within 30 min after tree inception (TIV) in unfilled Silicone Rubber (SiR) as well as in SiR/Alumina nanocomposites up to 3 vol.%. Once TIV occurred, fixed 8 kVrms, 50 Hz Ac supply voltage was stressed to the specimen in order to monitor the electrical tree growth process within this period of time. The result shows that the tree growth pattern appears regularly in Branch tree type during the growth process for unfilled SiR while Bush tree type can be observed more frequently by increasing nano-alumina up to 2 vol.%. However at 3 vol.%, the fastest electrical tree growth can be observed and most of the trees tend to appear in Pine Branch tree pattern due to the slight agglomeration in filler dispersion. The result shows that, up to 2 vol.% for homogenous dispersion of filler, nano alumina can act as a resistance of electrical growth but further filler increasing up to 3 vol.% lead to the worst propagation rate.

M. Hafiz, M. Fairus, M. Mariatti, M. Kamarol

A Modeling of Small Photovoltaic Power Plant Connected to Grid

In this paper a modelling and simulation of a small Photovoltaic (PV) Power Plant system connected to grid through MATLAB programming was presented. The model contains a detailed representation of the main components of the system that are the solar array, DC-DC boost converter, maximum power point tracking (MPPT), controller, inverter control circuit and utility grid. By controlling magnitude of DC-DC converter and inverter frequency, the active and reactive power changes that send to grid can be controlled. The results have been confirmed by legitimacy of models and control plans.

Syafrudin Masri, Paaventhan Raj

Minimal Cut Sets Deduction Using a Simple Method via Tracing Minimal Paths to Assess Reliability of Power Systems

A reliability study on random occurrences of undesirable failures or events during the lifetime of a physical system is conducted. Fault tree analysis is a powerful technique through which the reliability and safety of power systems can be assessed and suggestions for improvement can be provided. A minimal cut set (MCS) represents the combinations of component failures that can lead to the failure of the entire system. Fault tree analysis is the process of identifying the combinations of basic events that cause the occurrence of the top event. Top event is a main event of interest, for which the logic model is constructed. As the system becomes more interconnected, the MCS form that is graphically represented by a fault tree will be difficult to establish. This paper reports on a new method to deduce MCS by following a failure path based on a fault tree to assess the reliability of power systems. This method uses the incidence matrix and logic for numerous flow paths from the power sources to the loads. The proposed matrix can be presented as input data to any computer program (or simulation). Finally, the proposed method can be applied in complicated networks. An illustration shows the details and characteristics of the proposed method.

Athraa Ali Kadhem, Noor Izzri Abdul Wahab

Effect of Nano Titanium in SiR/EPDM Composite on Electrical Surface Tracking Under Incline Plane Test

Nowadays, the incorporation of inorganic nano-particles such as alumina and silica into polymeric material had produced a better electrical properties than polymer alone. Especially, in minimizing the effects of surface tracking in high voltage insulation material due to environmental stress. However, the investigation on surface tracking with composite of nano-titanium in SiR/EPDM polymeric material still unknown. Therefore, this paper presents the effect of various nano-titanium concentration in SiR/EPDM composite on the electrical surface tracking. The nano-composites have been prepared into several batches for instance unfilled, 1 and 2 vol.% concentration. The properties of nano-composites such as tracking time, leakage current magnitude and surface condition were analyzed under Incline Plane Tracking (IPT) test. The experimental setup was carried out based on the IEC 60587 standard with a constant applied a.c voltage at 4.5 kVrms and 0.6 ml/min contamination flow rate. The results revealed that the effects of nano-titanium in SiR/EPDM composite significantly influenced the properties of surface tracking. The increment of nano-titanium with 1 and 2 vol.% were found to have a good resistance to surface tracking on the composite.

M. Fairus, M. Hafiz, M. Mariatti, M. Kamarol

Evaluation of the Economic and Environmental Aspects of Using Photovoltaic Water Pumping System

Desertic areas suffer from a lack of water, whether for drinking or irrigation. Moreover, the wide speared of these areas makes connecting it with electricity lines tough and expensive. Stand-alone Photovoltaic (PV) array showed it effectiveness in solving these problems in many places of the world. In this paper, the Software HOMER and REPS.OM used as numerical methods to design a PV water pumping system suitable for Omani rural and desertic areas depending on hourly meteorological data. The optimum design used to supply an irrigation pumping system. The selected system capital cost as well as its energy costs compared to diesel generator and systems in literature. The comparison shows that the proposed system results in a proper cost of energy and lower environmental pollution.

Ali H. A. Al-Waeli, Atma H. K. Al-Kabi, Asma Al-Mamari, Hussein A. Kazem, Miqdam T. Chaichan

Harmonic Behavior of Different Branded LED Lamps and Their Respective Cost Effectiveness

Changing incandescent lamps and Compact Fluorescent lamps (CFL) to light emitting diodes (LED) is one of the ways in enhancing energy efficiency in a building. LED lamps consume less power, longer lifespan and are environmental friendly because it is recyclable and does not contain mercury. However, LED lamps like CFL lamps create power quality (PQ) problem. LED lamps using electronic driver intended for changing AC to DC supply, switching and shifting of the driver can cause harmonic distortion for the connected system. Connecting a massive number of LED lamps can cause problems to the grid with the generated harmonic. This paper analyses the harmonic behavior for different branded of LED lamps based on IEC 61000-3-2 standard. Simulation of LED lamps will carry out by PSCAD/EMTDC software. Good quality LED lamps will produce lower harmonic distortion and the prices are also reasonable, so it can be high economical for the consumer. Thus, cost-effective of using LED lamps will be included in this paper.

Soo Chin Chong, Dur Muhammad Soomro

Implementation of Adaptive Neuro-Fuzzy Inference System in Fault Location Estimation

This paper proposed a new scheme using hybrid intelligent technique that combines artificial neural network and fuzzy inference system. This technique, known as Adaptive Neuro-Fuzzy Inference System (ANFIS) has associated with the advantage of wavelet transform as a pattern recognition method. The algorithm used to identify the type of fault either single line to ground, double line, double line to ground or three phase occur on a power transmission line. Other than that, this scheme is capable to analyze the fault location without the knowledge of line parameters. A power clustering algorithm called Gustafson Kessel is implemented for better performance. Alternative Transient Program/Electromagnetic Transient Program (ATP/EMTP) is used for simulation purposes and Matlab for further analysis. Outcomes indicated that the scheme is efficient and has a high percentage of accuracy.

Amalina Abdullah, Channarong Banmongkol, Naebboon Hoonchareon, Kunihiko Hidaka

Inter-area Oscillation Damping in Power Systems with Deep Penetration of Wind Energy

The rapid growth of energy demand in the recent years mandated exploiting energy resources alternative to the conventional fossil fuel-based resources. Nowadays, the renewable energy resources became a fundamental component of the current power systems. Numerous challenges are induced by these recent bulk systems such as low-frequency inter-area oscillations. This paper investigates three methods to damp inter-area oscillation in power systems with deep penetration of wind energy, which are: incorporating power system stabilizers in the automatic voltage regulator controls of the conventional generator, implementing a static var compensator in one of the system busbars, and implementing a high voltage dc transmission system to connect weakly-tied areas within the system. These methods helped increase inter-area oscillation damping when implemented in a modified system based on the classical two-area system.

Dalia M. Eltigani, Syafrudin Masri

The Energy Efficiency Improvement and Management Program for Academic’s Building, Engineering Campus, Universiti Sains Malaysia

This paper presents the case study on the energy efficiency improvement and proposes the energy management program to reveal the potential of energy saving in School of Chemical Engineering (SCE)’s building, Engineering Campus, USM, which has high energy index among the academic building. The effective solution to control the energy conservation is by taking care the energy efficiency on the energy consumption in buildings through the Energy Audit and the Efficient Energy Management (EEMs) program. With reduction in consumer load, there is an opportunity to lower the load curve along with saving in energy bill due to the lowering the energy consumed.

Amir Halim, Syafrudin Masri

Electrical Machines, Drives and Power Electronics

Frontmatter

A Novel Five Switches Single Phase Full-Bridge Voltage Source Inverter

This paper presents a novel five switches single phase full-bridge voltage source inverter. In this topology, a control circuit is connected at the lower arm of a full-bridge switches to control the output voltage across the full-bridge inverter. The switch at the lower arm of the full-bridge controls the output of full-bridge inverter by increasing or reducing the voltage level at the lower arm of the bridge. This switch of lower arm is controlled by a high frequency sinusoidal pulse width modulation (SPWM) switching signal. While the power switches of full-bridge inverter operate with square wave switching signal at line frequency to unfold DC-AC. Hence, a sinusoidal shape of output ac voltage is achieved from the proposed inverter. Experiment is carried out to verify the performance of proposed topology. Experimental results with rated power 1000 W are presented to testify and validate the analysis, design and performance of proposed topology. From the presented results, it is shown that the proposed topology has nearly sinusoidal output voltage and current waveforms.

Muhammad Faizal Abdullah, Shahid Iqbal, Dahaman Ishak

The Fabrication and Characterization of Short-Stroke Tubular Linear Permanent-Magnet Motor

This paper describes the characterization and fabrication of tubular linear permanent-magnet motor (TLPMM). The motor is single-phase moving-magnet with a quasi-Halbach magnetization patterns. The soft magnetic composite (SMC) material, Somaloy 700, has been used for the fabricated stator core of the TLPMM and a single ring coil has been placed in this stator. Meanwhile, the translator consists of permanent-magnet (PM) rings, Neodymium Iron Boron (NdFeB) rode on a supporting tube made of ferromagnetic material. This kind of motor has a simple structure, high force capability, and high efficiency. Therefore, the proposed motor with these characteristics is possible to drive the piston in a reciprocating compressor of the refrigerator applications with more energy saving. Based on the simulation results from the Finite-Element Analysis (FEA), it is possible to fabricate a TLPMM with efficiency more than 94 %. Moreover, it is shown that the proposed motor has a capability to operate the reciprocating compressor in the refrigeration applications.

Izzeldin Idris Abdalla, Taib Ibrahim, Nursyarizal Bin Mohd Nor

LLC Resonant Converter Based Incremental Conductance Maximum Power Point Tracking System for PV Applications

Maximum power point tracking is one of the crucial element in photovoltaic (PV) power systems. Most of the conventional maximum power point tracking (MPPT) systems utilize pulse width modulated (PWM) dc-dc converter. PWM dc-dc converters usually have higher switching loss and high electromagnetic interference. On the other hand, resonant converters show good efficiency, soft switching capabilities and capable of high frequency operation over the conventional PWM converters. This paper proposes an incremental conductance MPPT using LLC resonant converter for PV power systems. The converter and the MPPT algorithm are implemented using MATLAB Simulink environment. The simulation results show the good performance of LLC resonant converter for maximum power tracking under varying environmental conditions.

Adrian Soon Theam Tan, Shahid Iqbal, Dahaman Ishak, Syafrudin Bin Masri

Investigation on Raspberry Pi Microcontroller as Digital Processing Controller in Back to Back Converter

This paper is about, the investigation of the Raspberry Pi as a microcontroller for back-to-back converter. The Matlab-Simulink is used as the communication medium between the software and the microcontroller and at the same time, controllers have been developed based on the mathematical formulas in the MATLAB. Three types of controllers have been designed and simulated which are voltage, current and power controllers with the PID and Hysteresis control mechanism in order to see the respond to the given reference signals at the converter output. Two of controllers, which are the voltage and current controls have been tested in hardware setup that consists of single phase diode bridge, 3-phase inverter and a resistive load. Those tests have shown, the Raspberry Pi is managed to generate the gate signals for the converter which respond to the controller without any programming code written in the Matlab.

Shamsul Aizam Zulkifli, Ibrahim Mamat, Muhammad Nor Hafiz Mokhtarudin, Shahrizan Ahmad Shah

Modeling of Steady State and Transient State of the Power Electronic Distribution Transformer

This research study presents a new type of power electronic distribution transformer (PEDT), aimed to overcome the disadvantages of the traditional electromagnetic distribution transformers. This new proposed model is named as power electronic distribution transformer incorporating power electronic converters in both primary and secondary sides, in addition to the high-frequency transformer. Moreover, the PEDT is capable of providing many advantages, such as power factor improvement, voltage sag/swell, reactive power compensation, harmonics elimination, self-protection and size reduction as compared to the conventional electromagnetic transformer. MATLAB/Simulink is used to simulate the proposed model. The simulation results show that the model is capable of offering an additional DC bus on the primary side as well as high power conversation ratios and power quality improvement.

K. Y. Ahmed, N. Z. Yahaya, V. S. Asirvadam, K. Ramani, N. M. Shannan

Fault Diagnosis of Voltage Source Inverter for Induction Motor Drives Using Decision Tree

In this paper, open-circuit faults of voltage source inverter for induction motor drives are investigated. Decision tree, which is an expert system that based on knowledge history with simple model, is applied to detect and classify the faults. Input data for fault diagnosis are collected and extracted from time-domain current signals. Knowledge data are set up from simulation and experiment for building and testing decision tree, and its evaluation results illustrate the potentiality of this method.

Ngoc-Tu Nguyen, Huu-Phuc Nguyen

Study on Vibrations and Noises in the Amorphous Steel Core Transformer Caused by Magnetostriction Effect

In this paper, general mathematical model with relevant factors to investigate the magneto mechanical coupling in magnetic core are considered. Experimental measurements of vibration and audible noise in amorphous steel cores of the transformer have been carried out. The results of the mathematical model were compared to the results of simulation by finite element method (FEM) of the previous research and experimental measurements. Magnetostrictive noise and vibration levels in the amorphous steel core have been identified higher than silicon steel core. Experimental results have shown the use of iron clamps on the leg and yoke with a reasonable clamping force permits a reduction in vibration amplitude and noise.

Do Chi-Phi, Phung Anh-Tuan

A Novel Bidirectional Two-Stage Inverter Based UPS System

This paper presents a novel bidirectional two-stage inverter based UPS system. In this system, a two-stage inverter is implemented where it consists of two power converters namely full-bridge LLC resonant DC-DC converter with high-step-up voltage conversion ratio and conventional full-bridge inverter. The system can be divided into two operating modes which are normal mode and backup mode. During normal condition, the grid is available and supplies the load as well as charges the battery through the bidirectional system. While on this condition, the system is operating in normal mode. When grid start failing, the bidirectional system switched to backup mode and converts battery power to supplies the load. This system offers several advantages such as reduced in power electronic interface, and low voltage regulation during grid failure. The steady state of the system is simulated and tested in MATLAB-Simulink.

Muhammad Faizal Abdullah, Shahid Iqbal, Dahaman Ishak

Analytical Subdomain Model of Surface-Mounted PM Synchronous Machine Using Virtual PM Blocks to Optimize Magnet Segmentations for Underwater Vehicle Applications

This paper presents an analytical subdomain model which can consider infinite numbers of virtual permanent magnet (PM) blocks to represent the segmented magnets per pole in any combination of slot and pole numbers of the semi-closed surface-mounted permanent magnet synchronous machines. From the case study discussed in this paper for a three-phase, 6 s/4p surface-mounted PMSM designed specifically for the underwater vehicle applications, the optimum magnet pole-arcs of the two segmented magnets per pole are 147.0° elect. for each magnet pole and 11.3° elect. for the airgap spacing between the magnet segments. The cogging torque and the total harmonic distortion of the phase back-EMF are drastically reduced by 88 % and 26 %, respectively, when comparing the results to the optimum magnet pole-arc of one magnet segment per pole machine, under similar constraint of PM volume. These analytical results are validated by 2D finite element analysis, where good agreement has been achieved.

Tow Leong Tiang, Dahaman Ishak, Mohamad Kamarol

Hybrid-Bridge LLC Series Resonant Converter for Deeply Depleted PEV Battery Charging

In this paper, a hybrid-bridge LLC series resonant converter with low circulating current and reduced switching losses for on-board battery charging of plug-in electric vehicle (PEV) is presented. Full-bridge (FB) is utilized in LLC converter with narrow range switching frequency within below resonance frequency region for depleted battery charging. To cover the charging voltage range for deeply depleted battery, the converter operates using half-bridge (HB) in both above and below resonance frequency regions. For both modes, the converter uses two fixed voltage levels at input to keep the switching frequency in narrow range. MATAB Simulink is used to simulate the converter with 3 kW maximum output power. Simulation results show that the LLC converter covers the wide charging voltage range 100–420 V for deeply depleted to fully charged battery using the constant-current, constant-voltage (CC-CV) charging, having lower turn-off current of power switches and low circulating current in resonant tank.

M. Imran Shahzad, Shahid Iqbal, Soib Taib

Backmatter

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