Conference Publications

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Prabakaran A/L Poopalan

The frequency dependent electrical parameters, such as impedance, electric modulus, dielectric constant and AC conductivity for ferroelectric Ba0.8Sr0.2TiO3 thin film have been investigated within the range of 1 Hz and 106 Hz at room temperature. Z* plane shows two regions corresponding to the bulk mechanism and the distribution of the grain boundaries-electrodes process. M" versus frequency plot reveals a relaxation peak, which is not observed in the ε″ plot and it has been found that this peak is a non-Debye-type. The frequency dependent conductivity plot shows three regions of conduction processes, i. e., a low-frequency region due to DC conduction, a mid-frequency region due to translational hopping motions and a high-frequency region due to localized hopping and/or reorientational motion.http://dx.doi.org/10.5755/j01.ms.17.2.490

Publication

Large Sized Slug on Solid State Lighting Stress and Temperature Analysis

( 2013)

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Vithyacharan Retnasamy

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Rajendaran Vairavan

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Phak Len Al Eh Kan

Publication

Hybrid logarithmic number system arithmetic unit: A review

( 2013)

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M.K Zakaria

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Logarithmic number system (LNS) arithmetic has the advantages of high performance and high-precision in complex function computation. However, the large hardware problem in LNS addition/subtraction computation has made the large word-length LNS arithmetic implementation impractical. In this paper, the concept of merging the LNS and Floating Point (FLP) operation into a single arithmetic logic unit (ALU) that can execute addition/subtraction and division/multiplication more faster, precise and less complicated has been reviewed. The advantages of using hybrid system were highlighted while comparing and explaining about FLP and LNS.

Publication

Biological sequence alignments: A review of hardware accelerators and a new PE computing strategy

( 2014)

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Muhammad Imran Ahmad

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Khaled Benkrid

One of the most challenging tasks in sequence alignment is its repetitive and time-consuming alignment matrix computations. In addition, performing sequence alignment in hardware, i.e. FPGA requires more hardware resources as the number of processing elements is replicated to increase performance throughput. This paper first reviews the existing FPGA-based biological sequence alignment core architectures and then proposed an efficient scheduling strategy, the so-called overlap computation and configuration (OCC) towards realizing optimized biological sequence alignment core architecture targeting for pairwise sequence alignment. In this research work, double buffering-based core architecture have been proposed and implemented on Xilinx Virtex-5 FPGA. Results have shown that this approach gained more than 10K times speed-up as compared to the GPP solution.

Publication

The design revolution of logarithmic number system architecture

( 2014)

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Publication

Analysis of FXP adders and multipliers for speed- and area-efficient LNS arithmetic unit

( 2014)

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J. N. Coleman

This paper portrays the selection of hardware unit architectures to be implemented in the new LNS based on a 32bit system. The implementations of the LNS multiply and divide only require a FXP adder, while the LNS addition and subtraction function comprised of several memories, FXP adders and multipliers together with other supporting logics. Thus, in choosing the best FXP adders and multipliers, each of the arithmetic is functionally verified and synthesised using Synopsys Design Compiler in Faraday 0.18 μm CMOS technology based on a 32-bit system. Two types of performance measurement, which are the worst-case delay and the silicon area, are chosen as the evaluation arguments. From conducted analytical studies, the CLA/CSLA adder and Booth recoded with Wallace tree multiplier were the best FXP adder and multiplier blocks to be applied in the system since they were the fastest designs. Using these blocks, the synthesis of the LNS system produced an approximately 7.10 ns of critical delay for addition and subtraction, and solely 1.16 ns for multiplication and division. The total area for a complete LNS architecture was 599,871 μm2, in which 65% the size of previously designed LNS architecture of ELM. © 2014 IEEE.

Publication

Design and analysis of a two-stage OTA for sensor interface circuit

( 2014)

Siti Nur Syuhadah Baharudin

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Asral Bahari Jambek

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This paper discusses the design of an operational transconductance amplifier (OTA) circuit foruse in a capacitive sensor interface circuit. The OTA converts a differential voltage input into the current as part of a switched capacitor integrator module. In this paper, a two-stage OTA is proposed which has high gain, high output swing and low noise. The circuit wasimplemented using 0.13μm Silterra CMOS technology and simulated using the Mentor Graphic Design Architect software package. The results show that the OTA is able to achieve74dB gain and 20KHz bandwidth when operated using a 2.5V power supply, with a total power consumption of 1.3mW. © 2014 IEEE.

Publication

An efficient processing element architecture for pairwise sequence alignment

( 2014)

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Muhammad Imran Ahmad

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Asral Bahari Jambek

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M. K. Md Kamil

Publication

Longitudinal, lateral and transverse axes of forearm muscles influence the crosstalk in the mechanomyographic signals during isometric wrist postures.

( 2014)

Md. Anamul Islam

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Kenneth Sundaraj

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R. Badlishah, Ahmad

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Sebastian Sundaraj

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Nizam Uddin Ahamed

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Md. Asraf Ali

Problem statementIn mechanomyography (MMG), crosstalk refers to the contamination of the signal from the muscle of interest by the signal from another muscle or muscle group that is in close proximity.

Purpose

The aim of the present study was two-fold: i) to quantify the level of crosstalk in the mechanomyographic (MMG) signals from the longitudinal (Lo), lateral (La) and transverse (Tr) axes of the extensor digitorum (ED), extensor carpi ulnaris (ECU) and flexor carpi ulnaris (FCU) muscles during isometric wrist flexion (WF) and extension (WE), radial (RD) and ulnar (UD) deviations; and ii) to analyze whether the three-directional MMG signals influence the level of crosstalk between the muscle groups during these wrist postures.

Methods

Twenty, healthy right-handed men (mean ± SD: age = 26.7±3.83 y; height = 174.47±6.3 cm; mass = 72.79±14.36 kg) participated in this study. During each wrist posture, the MMG signals propagated through the axes of the muscles were detected using three separate tri-axial accelerometers. The x-axis, y-axis, and z-axis of the sensor were placed in the Lo, La, and Tr directions with respect to muscle fibers. The peak cross-correlations were used to quantify the proportion of crosstalk between the different muscle groups.

Results

The average level of crosstalk in the MMG signals generated by the muscle groups ranged from: 34.28-69.69% for the Lo axis, 27.32-52.55% for the La axis and 11.38-25.55% for the Tr axis for all participants and their wrist postures. The Tr axes between the muscle groups showed significantly smaller crosstalk values for all wrist postures [F (2, 38) = 14-63, p<0.05, η2 = 0.416-0.769].

Significance

The results may be applied in the field of human movement research, especially for the examination of muscle mechanics during various types of the wrist postures.

Publication

Arithmetic addition and subtraction function of logarithmic number system in positive region: An investigation

( 2015)

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Logarithmic number system or LNS has become an optimal choice in digital image processing instead of floating point (FP) system based on latest researches in LNS. Digital image processing which deals with a lot of complex operations such as multiplication and division, makes LNS as a great choice of implementation. However, the implementation had been restricted by the addition and subtraction function in LNS arithmetic as these functions entail complex procedures and circuitry. As its huge potential to be a substitution of FP, there is an urgent need for LNS to improve the performance of both operations. Hence, various studies had been conducted in this area, however most of the research concern the implementation of these operations in the negative region. Therefore, this study is conducted with the objective on the exploration of both LNS addition and subtraction operations in the positive region and highlights the potential areas for design modifications and improvements. Then, these enhancements will be combined with other arithmetic functions in creating an optimum LNS design to be utilized in any digital image processing system.

Publication

An Analysis of Interpolation Implementation for LNS Addition and Subtraction Function in Positive Region

( 2016)

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Interpolation is among of the most popular approach used in approximating the values in logarithmic number system (LNS) arithmetic design. This method that often combines with lookup tables (LUTs) manages to produce efficient LNS design in area, latency and accuracy. Current research proves that the combination of interpolators with co-transformation in LNS subtraction had shown extreme improvements in terms of speed and area, which is comparable to floating point (FLP) performance. Taking the advantage, this research had been conducted to analyze the implementation of these three interpolators, which are Taylor, Lagrange and modified Lagrange, in a 32-bit environment of the LNS addition and subtraction procedures with the first-order co-transformation in positive region. The designs were analyzed in two categories, which are the accuracy towards FLP and the total memory consumption. The best interpolator was selected based on the most optimum area consumption design with manageable accuracy in FLP limit. The outcome of this analysis could benefit further improvements in LNS design.

Publication

Machine vision for laser defect in PV solar modules

( 2016)

R. Shuaimi

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This paper presents a new methodology in inspection on laser scribe defect of PV thin film solar modules. The work focuses on the application of machine vision as an inspection tools which has successfully integrated in other manufacturing environment as pattern recognition utility. Compared to manual inspection by human, machine vision system could offer better measurement accuracy as scribe defects are extremely hard to detect due to their small sizes and complexity of the detection process. Studies were made to identify machine vision system screening capabilities to define different scribe defect by their inspection criteria. Current result with paper and broad samples indicates that the propose system can be used effectively to replace human evaluators that currently employs in manufacturing quality control. © 2016 IEEE.

Publication

Implementation of LNS addition and subtraction function with co-transformation in positive and negative region: A comparative analysis

( 2016)

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The European Logarithmic Microprocessor (ELM) had been an outstanding breakthrough in logarithmic number system (LNS) research history. The processor successfully reaches the par ability of floating-point (FLP) processor with its rapid and accurate design towards FLP. The design was able to improve the LNS addition and subtraction procedure, which are the drawbacks of any implementation of LNS arithmetic. ELM's subtraction operation had adopted a unique approach, which is the first-order co-transformation to overcome the singularity-to-zero issue of the non-linear function in negative region. Therefore, this research had been introduced to extensively compare and analyze the ELM-based addition and subtraction procedures with the same co-transformation technique implemented in positive region. In achieving this, two aspects are considered, which are the accuracy towards FLP and the memory consumption of both procedures in both regions. Conclusively, the exact ELM-based implementation in positive region of both operations could be realized and achieved comparable accuracy and memory area with a slight modification of the operation procedure. The outcome of this analysis could benefit further investigation of optimizing the LNS design for hardware implementation.

Publication

A review on the Skyrme Hartree-Fock model and related topics

( 2017)

Nooraihan Abdullah

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Khairul Anwar Mohamad Khazali

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Publication

Structural and electrical properties of Barium Titanate (BaTiO3) and Neodymium doped BaTiO3 (Ba0.995Nd0.005TiO3)

( 2017)

Tuan Amirah Tuan Sulong

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Rozana Aina Maulat Osman

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Mohd Sobri Idris

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Zul Azhar Zahid Jamal

Barium titanate (BaTiO3) and Neodymium (Nd) doped BaTiO3 with composition Ba0.995Nd0.005TiO3 were prepared using conventional solid state reaction method to study the dielectric properties of materials. Pure phase samples were found at final heating temperature of 1400°C for overnight. X-ray diffraction analysis reveals the changes in the lattice parameter and unit cell volume of the pure perovskite tetragonal structure with space group (P4mm). Electrical analysis is carried out to investigate the dielectric properties, conductivity behaviour and dielectric loss of BaTiO3 and Ba0.995Nd0.005TiO3. Ba0.995Nd0.005TiO3 have a broaden dielectric peaks with high permittivity of 8000 and reasonably low loss tan δ which is about 0.004 (1 kHz).

Publication

Kinetics, mass transport characteristics, and structural changes during air-drying of purple yam (Dioscorea Alata L.) at different process conditions

( 2017)

Flordeliza C. De Vera

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Leif Anthony B. Comaling

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Iya Ray Alyanna M. Lao

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Alvin R. Caparanga

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This experiment was designed to follow the 2k factorial design to study the effects of the three drying parameters on the drying characteristics and effective moisture diffusivity and to fit each run performed on the best thin-layer drying kinetics model. Raw purple yam samples were pre-treated and undergone the designed drying procedures at which the weight of the samples were recorded every minute until such time that the sample weights become constant. Scanning Electron Microscopy (SEM) is utilized for qualitative analysis of the dried samples. The number of pores per unit area and the overall aesthetics of the surface of the dried samples were compared also using SEM. Considering the qualitative analysis conducted on the samples from the images of SEM, dried samples from run 2 has the most desirable conditions such as high temperature and low air velocity for drying because the samples from this run have large pore diameters with minimal cell breakages.

Publication

Digital fringe projection for hand surface coordinate variation analysis caused by osteoarthritis

( 2017)

Wan Mokhdzani Wan Nor Haimi

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Cheek Hau Tan

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Vithyacharan Retnasamy

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Rajendaran Vairavan

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Muhammad Hafiz Ab Aziz

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Nor Roshidah Yusof

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Nor Azura Malini Ahmad Hambali

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Ahmad Syahir Ahmad Bakhit

Hand osteoarthritis is one of the most common forms of arthritis which impact millions of people worldwide. The disabling problem occurs when the protective cartilage on the boundaries of bones wear off over time. Currently, in order to identify hand osteoarthritis, special instruments namely X-ray scanning and MRI are used for the detection but it also has its limitations such as radiation exposure and can be quite costly. In this work, an optical metrology system based on digital fringe projection which comprises of an LCD projector, CCD camera and a personal computer has been developed to anticipate abnormal growth or deformation on the joints of the hand which are common symptoms of osteoarthritis. The main concept of this optical metrology system is to apply structured light as imaging source for surface change detection. The imaging source utilizes fringe patterns generated by C++ programming and is shifted by 3 phase shifts based on the 3 steps 2 shifts method. Phase wrapping technique and analysis were applied in order to detect the deformation of live subjects. The result has demonstrated a successful method of hand deformation detection based on the pixel tracking differences of a normal and deformed state.

Publication

Design of 5 V DC to 20 V DC switching regulator for power supply module

( 2017)

Nor Afiqah Azmi

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Azizi Harun

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