Journal Articles

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  • Publication
    Frequency dependent electrical properties of ferroelectric Ba₀.₈Sr₀.₂TiO₃ thin film
    ( 1970)
    Ala’eddin A. SAIF
    ;
    Zul Azhar Zahid Jamal
    ;
    Zaliman Sauli
    ;
    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
      4  18
  • Publication
    Development of multiband fractal planar inverted F antenna (F-PIFA) for mobile applications
    ( 2009)
    Saidatul Norlyana Azemi
    In the past few years, demand in unification of wireless hardware has propelled new development of antenna. With the advances on antenna technology, it becomes attractive to enhance the capabilities of antenna in many areas such as mobile communication and wireless application. The requirements of ubiquitous antenna are small in size, simple, robust, have a shielding mechanism, multisystem and wide bandwidth. The reason is, currently, there are five bands that are assigned for world mobile services. Due to the aforementioned issues, a novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity design is presented in this research. This research is conducted in order to develop an antenna with low cost, small in size, high performance, and capable to operate at multiple frequency bands. The F-PIFA development processes include specification definition, selection of the dielectric material and construction of prototype using CST software tools. In conducting this research, the production of prototypes is divided into three stages. The first stage is to develop three different iteration of F-PIFA and to evaluate its performance. The second stage is to fabricate, measure the antenna performance as well as the SAR value. Finally, the design is investigated and improved for future works. This research has successfully produced an antenna with good efficiency without degrading bandwidth and gain of the F-PIFA. The antenna has a total dimension of 27mm x 27mm is designed and optimized in order to receive GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telecommunication System) and HiperLAN (HigH Performance Radio LAN) with the frequency range from 850-960 MHz, 1900 MHz to 2100 MHz, 1885 to 2200 MHz for 3G and 4800 MHz to 5800 MHz for HiperLAN respectively. This omni-directional antenna invented here have 65-90% efficiency with peak gain value that is 3.57 dB, and be able to produce less than 2W/kg SAR value.
  • Publication
    Nano-silver microcavity enhanced UV GaN light emitter
    ( 2009)
    Ahmed, Naser Mahmoud
    ;
    Zaliman Sauli
    ;
    Uda Hashim
    ;
    Zul Azhar Zahid Jamal
    We report results of measurements that help to clarify the role of silver in the reflection of UV emission light from GaN. A GaN as an active layer was sandwiched between two silver metal reflectors. GaN layer on sapphire showed a photoluminescence (PL) peak around 364 nm and its full width half maximum was about 6.7 nm. Two types of microcavity, were fabricated: half-cavity GaN/sapphire/silver and full-cavity silver/ GaN/sapphire/silver. Photoluminescence measurements showed a two-fold intensity enhancement in half-cavity back mirror. In the full cavity samples, the amplitude of the photoluminescence is enhanced ten times when we used 50 nm silver as a front mirror. A tremendous more than 16-fold enhancement is obtained when silver mirror of 25 nm was used as a front mirror. The increase in the photoluminescence intensity is explained in terms of competition between increasing absorption in the cavity, silver surface plasmon coupling and increasing optical field-enhancement due to resonator.
      3  8
  • Publication
    A 1.5 V, 0.85-13.35 GHZ MMIC low noise amplifier design using optimization technique
    ( 2009)
    Arjuna Marzuki
    ;
    Ali Yeon Md Shakaff
    ;
    Zaliman Sauli
    This paper describes how a broadband, 1.5 V, 0.85-13.35 GHz low noise amplifier in 0.15 μm 85 GHz PHEMT process is synthesized to simultaneously meet multiple design specifications such as bandwidth, noise figure, power gain and power consumption. Power-constrained synthesis technique is used to design the broadband amplifier. The simulated peak S21 is 19.8 dB, maximum noise Figure is 2.5 dB, 3-dB bandwidth is 12.5 GHz and power consumption is 73.5 mW. The calculated Figure of merit (FOM) is better than many reported broadband low noise amplifier (LNA).
      2  4
  • Publication
    Design and development of pyramidal microwave absorber using agricultural waste
    ( 2011)
    Nornikman Hassan
    Agriculture waste has potential to be used as an alternative material for the microwave absorber that used in the RF anechoic chamber. Compared to the current material that used in the commercial market such as polystyrene and polyurethane, the agricultural waste is low cost material and environmental friendly. This rice husk pyramidal microwave absorber can operate effectively in the microwave frequency range from 7 GHz to 13 GHz. In this research, agricultural waste of rice husks from paddy is used as the main material that mixed with resin and hardener agent for the pyramidal microwave absorber design. Other agricultural waste like rice straw and kenaf are also used to compare its reflection loss performance with rice husk absorber. Polyester is used as resin that mixed with agricultural waste and methyl ethiyl ketone peroxide (MEKP) hardener. Other resin like Urea Formaldehyde (UF) and Phenol Formaldehyde (PF) are also used to compare its reflection loss performances. There are six main stages in designing and development of the rice husk pyramidal microwave absorber. The first stages are fabricating the agricultural waste particle board. Secondly, the stage is continuing with deriving the dielectric properties value of the agricultural waste mixture particle board using the free space measurement technique. The third stage is to define the best reflection loss result of the agricultural waste pyramidal microwave absorber using CST Microwave Studio simulation software. The dielectric properties that used in this simulation are taken from the free space measurement technique result that had been done before. Various parameters that affect the performance of the pyramidal microwave absorber are investigated in the parametric study section. The parametric study that taken care in this simulation are different shape, dimension, resin percentage, carbon coating thickness, distance of source signal, angle of source signal, and polygonal side. Then, it continued by fabrication process of the rice husk pyramidal microwave absorber using pyramidal shape with square base mould. The last stage is to measure the reflection loss performances of the fabricated rice husk pyramidal microwave absorber. In this section, the result of the simulation and fabrication of the pyramidal microwave absorber are compared. Measurement results show close agreement with the simulation result. In the other side, the commercial and fabricated absorber is also considered to compare it reflection loss. It show that the reflection loss performance is better than - 30 dB in the range between 7 GHz and 13 GHz.
  • Publication
    A low complexity OFDM modulator/demodulator based on discrete hartley transform
    ( 2011)
    Zakaria Sembiring
    The investigation upon to discrete Hartley transform (DHT) to replace the conventional complex-valued and mature discrete Fourier transform (DFT) as the OFDM modulator and demodulator was carried out in this research. The overall project is divided into two parts as follows: firstly, the proposed system is simulated under various parameters such as BER versus SNR and the quality of image versus given value of SNR. Secondly, the simulation model has been developed using excellent software for simulation, MATLAB. Statistically analysis has been investigated to measure the accuracy of the system performance and also the complexity of the system. Simulation results show that the system complexity is reduced in term of multiplication and addition number. For number of subcarriers, N = 64, 52 % of multiplication and 28 % of addition numbers are reduced. The system performance is measured in term of plotted graph of BER versus SNR and quality of received image versus SNR, where the BER value is 10-3 and quality of image is similar with the original image when the given value of SNR = 30 dB.
  • Publication
    Development of video image acquisition for traffic surveillance using open source software
    ( 2011)
    Zainab Nazar Khalil Wafi
    The Research works to presents an innovative approach in monitoring system by applying new programming methods which can be used for Traffic/Road Surveillance Systems. Nowadays, the development of traffic surveillance on the road is compulsory as highways and roads are getting crowded especially in the cities. These crowded situations would increase the number of accidents on the roads. The Traffic Surveillance System performs image recognition and object tracking processing. A camera is used to monitor specific roads (highways, motorways, junctions…etc) and communicate with the main server. The main server integrates the target image from the camera after processing it in several steps then communicates with another computer by sending the image to it. A prototype implementation of traffic surveillance is based on OpenCV programming under GNU-Linux supported by socket programming. The objectives of traffic surveillance system are tracking moving vehicles, counting them and detecting the abnormal movement in specific places. This is done by analyzing the frames captured and processing them using OpenCV functions. The use of open source resources such as OpenCV functions in GNU- Linux provides an easy method to use the computer vision framework besides it can run vision code in real time. The traffic surveillance works in real-time process for (5-33 fps) of video stream in a rainy day and a sunny day. Traffic surveillance system accepts video images either from the camera captures or from the files. It tracks the moving vehicles using image processing and recognition algorithms such as converting to Gray scale and Mixture of Gaussian method; it marks each moving vehicle with a rectangle box and counts them. The system consists of: capturing part, tracking part, detecting abnormal movement from specific points and streaming the view to the other connecting computer. Besides it could minimize the frame processing in the case of the frame capture with high resolution. The system has successfully been tested in three different processor speeds which are 1.2 GHz CPU, 2.0 GHz CPU and 2.6 GHz CPU. The results are quite accurate and are measured in mille second. The system works in outdoor environment which is complex with wavering tree branches and flow of rain. Besides it updates frame by frame in any module of background views especially from the upper view of the road in order to get a significant images of all the objects. The results could be recorded by saving the requested group of photos in any image format. The CPU processing speed with the frame size process represents one of the key factors of the performance analysis of traffic surveillance. Processing speed comparison of the processing steps results in different resolutions for frame size made. And, a significant result is found by reducing the calculation time of processing when the frames size captured are reduced. The experiment was done by using 9 different views each with 700 frames consist of different views of moving vehicles in sunny or rainy situations on the roads of Perlis state. These experiments successfully detected the movements of all types of vehicles.
  • Publication
    Smart network traffic monitoring system
    ( 2012)
    Naufal Alee
    The rapid Internet development has eventually increased the network traffic as well. Therefore, the IP-based network traffic measurement has attracted network administrators and organizations for commercial, social and technical purposes. The need for traffic measurement is to understand the network itself in terms of the reliability and performance. Thus, Network Analyzer (NA) is developed to be able to analyze network traffic. Developments in embedded system technologies making it possible to design new low operational-cost but highly flexible NA systems. The core of the developed system is an embedded hardware running a scaled-down version of Linux Operating System (OS), a popular choice of operating system for embedded applications. This research proposed a new design and development of a Smart Network Traffic Monitoring (SNetMon) system based on single board computer (SBC) and using open source embedded GNU/Linux OS. The system is capable of capturing network packet, analyze and display data. The system is a portable device for network administrator to analyze network traffic. The main hardware components of SNetMon system are TS-7800 SBC, LCD panel and SD card. SNetMon software system is also a portable software which able to run on large variety of device platform. It is composed of three modules; Capturing Packet Module (CPM), System Control Module (SCM) and View Module (VM). CPM is developed using C language to capture, extract, analyze and store data. SCM is developed using PHP language to control CPM, query selected data and save into JavaScript Object Notation (JSON) format. VM is developed using Hyper Text Markup Language (HTML), Cascading Style Sheet (CSS) and JavaScript language. It will be loaded and processed from the client side by web-browser, analyze the data and to plot graphs. SNetMon system performance is compared between PC and Wireshark, a well known de facto standard network analyzer. Result depicted show data capture rates of SNetMon is very much identical with wireshark (less than 0.1%) during execution. The performances of two difference GNU/Linux kernels, 2.6.21 and 2.6.34, are reported. Results indicate that the new kernel has better performance, more bandwidth and low latency. The results prove that SNetMon on SBC system design and implementation is highly competitive even though it has low processing power and memory.
  • Publication
    Dual-band planar bowtie monopole for a fall-detection radar and telemetry system
    ( 2012)
    Ping Jack Soh
    ;
    Marco Mercuri
    ;
    Gokarna Pandey
    ;
    Guy A. E. Vandenbosch
    ;
    Dominique M. M.-P. Schreurs
    A dual-band planar bowtie monopole for a fall-detection radar and telemetry system is presented. Unidirectionality is successfully enabled by a full ground plane. A compact radiator footprint is achieved by closely spacing two bowtie elements for transmit–receive operation, combined with a simple and effective technique for mutual-coupling reduction. The radar antenna shows target location and speed detection capabilities of up to 4 m with resolution of 30 cm and fall-detection success rate of 95%. Its telemetry capability is then validated practically by frame transmissions through this antenna, which are successfully received by a base station located 5 m away.
  • Publication
    Development and analysis of wearable textile antenna (WTA) design for ISM and hiperlan applications
    ( 2012)
    Nurul Husna Mohd Rais
    In recent years, there has been growing interest in utilizing wearable textile antennas for Body Area Network (BAN) antenna applications. Availability of conductive textiles allowed manufacturing of light-weight and flexible wearable antennas made entirely out of textiles. The proposed antenna is designed and optimized for both ISM (Industrial, Science and Medical) and HiperLAN (High Performance Radio LAN) applications, where operating frequency ranges from 2400 to 2480 MHz and 5150 to 5750 MHz, respectively. Previously, conventional microstrip antenna designs fabricated using rigid printed circuit board (PCB) laminates are unable to conform to BAN's flexibility and deformity prerequisites. On the contrary, the proposed antenna in this investigation is fabricated using conductive textiles, which are built using a combination of conductive polymer/metal fibers and normal fibers. The development procedure of this Wearable Textile Antenna (WTA) starts with its specification definition, materials selection, simulation using CST Microwave Studio software and finally, design prototyping and measurements. Due to the manual fabrication procedure employed, the antenna designed is to be as simple as possible. The proposed basic rectangular radiator is then improved using slots and slits to enable dual-band resonance and broad bandwidths. Its main structural design concept is based on a suspended plate antenna - a 60 × 45 mm rectangular radiating element is suspended over a 80 × 60 mm ground plane using a 5 mm foam substrate. The antenna has undergone several investigations to ascertain its overall performance. Performance of the antenna investigated in free space, placements on different body locations and under different bending radii. S11, gain and efficiency of the antenna in free space and in proximity of human body showed good agreements, indicating design robustness under various operating conditions.
  • Publication
    Implementation and analysis of GMM-based speaker identification on FPGA
    ( 2012)
    Phak Len Al Eh Kan
    The use of highly accurate identification systems is required in today’s society. Existing systems such as pin numbers and passwords can be forgotten or forged easily and they are no longer considered to offer a high level of security. The use of biological features (biometrics) is becoming widely accepted as the next level for security systems. One of the biometric is the human voice and it leads to the task of speaker identification. Speaker identification is the process of determining whether a speaker exists in a group of known speakers and identifying the speaker within the group. Speaker specific characteristics exist in speech signals due to different speakers having different resonances of the vocal tract. These differences can be exploited by extracting Mel-frequency Cepstral Coefficients (MFCCs) from the speech signal. A statistical modelling process known as Gaussian Mixture Model (GMM) is used to model the distribution of each speaker’s MFCCs in a multi-dimensional acoustic space. GMM involves with two phases called training and classification. The training phase is complex and is better suited for implementation in software. The classification phase is well suited for implementation in hardware and this allows for real time processing of multiple voice streams on large population sizes. Several innovative techniques are demonstrated which enable hardware system to obtain two orders of magnitude speed up over software while maintaining comparable levels of accuracy. A speedup factor of eighty six is achieved on hardware-based FPGA compared to a software implementation on a standard PC for this approach.
  • Publication
    On-body characterization of dual-band all-textile PIFAs
    ( 2012)
    Ping Jack Soh
    ;
    Stephen J. Boyes
    ;
    Guy A. E. Vandenbosch
    ;
    Yi Huang
    ;
    Soo Liam Ooi
    Antenna performance in terms of reflection coefficient, bandwidth, radiation pattern and efficiency is expected to be severely influenced during on-body deployment. Besides addressing the need for a systematic on-body evaluation procedure, this work presents an in-depth discussion on the measured degradation relative to free space operation. Considering a practical deployment scenario, the two antenna designs are first optimized in proximity of a human-emulating box using a commercial simulator. Shield It textile is chosen to build the antenna's conductive components, and this prototype is then benchmarked against another similarly-dimensioned prototype constructed using copper foil. For each material, two dual-band prototypes are fabricated, one resonating at 2.45 GHz and 5.2 GHz, and the other at 2.45 GHz and 5.8 GHz. Two realistic on-body deployment locations are chosen to be investigated, on the chest and back, considering two antenna orientations - one radiating away from the user, and the other radiating along the body. Free space and on-body reflection coefficient, bandwidth and radiation pattern are evaluated for each prototype in an anechoic chamber, while a reverberation chamber is utilized to determine their efficiency. All measurements were carried out using the same human volunteer. Evaluations show that coupling distance and conductivity are the main factors in determining efficiency rather than on-body location, given that evaluations are carried out while the antenna keeps its planar form.
      1  3
  • Publication
    Modified global and modified linear contrast stretching algorithms: new colour contrast enhancement techniques for microscopic analysis of Malaria slide images
    ( 2012-10-03)
    Aimi Salihah Abdul Nasir
    ;
    Mohd Yusoff Mashor
    ;
    Zeehaida Mohamed
    Malaria is one of the serious global health problem, causing widespread sufferings and deaths in various parts of the world. With the large number of cases diagnosed over the year, early detection and accurate diagnosis which facilitates prompt treatment is an essential requirement to control malaria. For centuries now, manual microscopic examination of blood slide remains the gold standard for malaria diagnosis. However, low contrast of the malaria and variable smears quality are some factors that may influence the accuracy of interpretation by microbiologists. In order to reduce this problem, this paper aims to investigate the performance of the proposed contrast enhancement techniques namely, modified global and modified linear contrast stretching as well as the conventional global and linear contrast stretching that have been applied on malaria images ofP. vivaxspecies. The results show that the proposed modified global and modified linear contrast stretching techniques have successfully increased the contrast of the parasites and the infected red blood cells compared to the conventional global and linear contrast stretching. Hence, the resultant images would become useful to microbiologists for identification of various stages and species of malaria.
  • Publication
    Development of a novel intelligent wireless sensor actor network for agricultural applications
    ( 2013)
    Naseer Sabri Salim
    Deployment of a successful wireless sensor actor network requires intelligent processing schemes, effective power consumption and reliable communication links. A novel intelligent wireless sensor-actor network (IWSAN) based on Fuzzy Inference System for agricultural greenhouse climate control is presented in this research. The two most important mutual effects agricultural greenhouse climate parameters are considered which are the temperature and humidity during diurnal and nocturnal time. Design, simulation and implementation of IWSAN for agricultural greenhouse climate control based on Fuzzy Inference System is outlined both for off the shelf and handmade platforms. The integration of artificial intelligence with WSAN proves superior features in comparison with traditional wired control systems and simple wireless monitoring and acting network. IWSAN proves high efficiency of controlling task of ±0.5 and ±1 tolerance of setting points, scalability, mobility and cost effective of handmade platform, beside flexibility of using the system in various geographical areas besides the capability of tuning the whole system for other agricultural tasks. New Dynamic Check-In Interval technique (DCI) is modelled and developed to prolong the lifetime of network sensor nodes. It is implemented as software embedded in sensor nodes while a proposed hardware solution is conducted. The DCI technique of software implementation offers maximum of 10days while 367days for proposed hardware solution with a threshold value of 0.5. IWSAN of non beacon start network topology provides a 1.24 year lifetime for sensor nodes based 1 minute sleep period and powered by 210mAh battery. In agricultural greenhouse, unreliable link quality of IWSAN may raise unpredictable packet loss that is considered as a factor of more noteworthy effect on the performance of the control system. The system reliability of IWSAN in the greenhouse is high with minimum success rate of packet transmission of 85% and achieves settled performance during one week of operation. The unpredictability in the system performance is minimized when one or more sensor nodes are failed. Vegetation path loss in the greenhouse is modelled as a function of antenna heights, separation distance and various foliage depths, simulated with square grid distribution scheme and programmed to assist nowadays well known WSN simulators. The maximum partitioning distance for reliable communication in vegetation field is determined where network connectivity based on MED vegetation model shows perfect connectivity of 100% of foliage depth less than 50m while ITU model exposes less connectivity of about 88%.
  • Publication
    Interrogation of surface roughness and bond force effect
    ( 2013)
    Zaliman Sauli
    In the macro world surface roughness is a feature undoubtedly not to be ignored. In the current trend towards the nano-scale feature in the devices related to the semiconductor and other various niche, surface roughness is being propelled as an important element. In this work the surface roughness at nano level is investigated for the adhesion interaction and influence. The samples for the roughness feature and ranges were prepared using controlled plasma etching. The wire bonding bond force parameter was chosen as the factor to be tested and shear test as the response. The shear value ranged from 13g to 22g for the low to high bond force respectively for the lower range surface roughness, for the higher surface roughness the value ranged 5g to 9g respectively. The interaction shows surface roughness has tangible effect on adhesion for a more thorough detailed investigation.
  • Publication
    Improved addition and subtraction in logarithmic number system: Technique and analysis
    ( 2013)
    Rizalafande Che Ismail
    ;
    N. Norzahiyah
    ;
    Asral Bahari Jambek
    Logarithmic Number System (LNS) is an alternative beside Floating Point (FLP) when an application requires a large dynamic range in the number processed. It allows simple implementation of multiplication and division using a Fixed Point (FXP) method without rounding error. In contrast, LNS addition and subtraction become more complex procedure. Therefore over the year, difference ways of improving the addition and subtraction function have been purposed. In this paper several techniques have been discussed and analysed such as direct lookup table, interpolation, table partitioning and co-transformation for approximating LNS addition and subtraction.
  • Publication
    Synthesis of multilevel and binary sequences with good correlation properties
    ( 2013)
    Siti Julia Rosli
    In radar systems the very low side lobes that can be achieved with amplitude and phase modulated pulse trains especially particularly in systems requiring a large dynamic range. Moreover, the excellent self-clutter rejection performance is obtained without sacrificing the ability for the separation of close targets (no main lobe widening). The additional expense of encoding and decoding in amplitude and phase may be justified for radars that must cope with land clutter or operating in a dense-target environment. To choose a suitable transmit waveform is an important problem in radar design. This is so because, the waveform controls resolution, clutter performance and also bears heavily on the system cost. Theoretical studies which provide the basis for technical advances have not so far solved the general signal design problem. The knowledge about the properties of the pulse trains shows that, a class of signals particularly well suited to digital processing of increasing practical importance. Two properties of such sequences are of interest. One is the energy ratio (ER) defined as the ratio of the total energy of the sequence to the energy of the largest pulse. The other property is the total side lobe energy (SLE) which is the energy in the side lobes of the autocorrelation function of the sequency. The work presented in this research is mainly concerned with the synthesis of multilevel and binary waveform of any desired length that has high energy ratio and low side lobe in their autocorrelation function (ACF). For the design of multilevel sequences in iterative technique is proposed, this techniques employed the properties of optimum inverse filtering and shown to be effective for the generation of multilevel sequences in any desired lengths. The method of clipping proposed in this research converts a multilevel sequence to binary sequence in same lengths while it is still retaining at low side lobe in autocorrelation function. It is shown that the iterative method based on inverse filtering and the method of clipping provide effective techniques for the generation of multilevel sequences that have high energy ratio and low side lobe energy in their autocorrelation function. Such sequences can then be effectively used to improve the range and Doppler resolution of radars.
  • Publication
    Mechanomyogram for Muscle Function Assessment: A Review
    ( 2013)
    Md. Anamul Islam
    ;
    Kenneth Sundaraj
    ;
    R Badlishah Ahmad
    ;
    Nizam Uddin Ahamed
    Background: Mechanomyography (MMG) has been extensively applied in clinical and experimental practice to examine muscle characteristics including muscle function (MF), prosthesis and/or switch control, signal processing, physiological exercise, and medical rehabilitation. Despite several existing MMG studies of MF, there has not yet been a review of these. This study aimed to determine the current status on the use of MMG in measuring the conditions of MFs. Methodology/Principal Findings: Five electronic databases were extensively searched for potentially eligible studies published between 2003 and 2012. Two authors independently assessed selected articles using an MS-Word based form created for this review. Several domains (name of muscle, study type, sensor type, subject’s types, muscle contraction, measured parameters, frequency range, hardware and software, signal processing and statistical analysis, results, applications, authors’ conclusions and recommendations for future work) were extracted for further analysis. From a total of 2184 citations 119 were selected for full-text evaluation and 36 studies of MFs were identified. The systematic results find sufficient evidence that MMG may be used for assessing muscle fatigue, strength, and balance. This review also provides reason to believe that MMG may be used to examine muscle actions during movements and for monitoring muscle activities under various types of exercise paradigms. Conclusions/Significance: Overall judging from the increasing number of articles in recent years, this review reports sufficient evidence that MMG is increasingly being used in different aspects of MF. Thus, MMG may be applied as a useful tool to examine diverse conditions of muscle activity. However, the existing studies which examined MMG for MFs were confined to a small sample size of healthy population. Therefore, future work is needed to investigate MMG, in examining MFs between a sufficient number of healthy subjects and neuromuscular patients.
  • Publication
    Performance evaluation of enhanced-TCP in wireless IPv6 network
    ( 2013)
    Yew Been Seok
    The TCP congestion control algorithm is used to minimise the congestion in a network and to improve the performance of TCP. The TCP congestion control algorithm is originally designed to operate in wired network. When the TCP congestion control algorithm is implemented in a wireless network, the TCP congestion control algorithm assumptions are violated and result in performance degradation in a wireless network. This thesis presents the enhanced-TCP Vegas congestion control algorithm to optimise the performance of TCP in a wireless IPv6 network. Three enhancements are proposed in the enhanced-TCP Vegas algorithm. The first enhancement is to minimise the bursty traffic flow at the TCP sender network. The first enhancement is called Packet Spacing. The second enhancement is to optimise the probing of the transmission rate into the network. The second enhancement is called Progressive CWND. The third enhancement is to differentiate between the real congestion and the spurious congestion in the wireless network. The third enhancement is called Congestion Measure. The proposed algorithm is implemented in ns-2. The simulation experiment is conducted in two scenarios. The first scenario investigates the performance of TCP Vegas algorithms in single TCP connection network. The results of simulation experiment show that the enhanced-TCP Vegas algorithm, which combines the packet spacing, progressive CWND and congestion measure methods performs compared with the other TCP congestion control algorithms that are used in this research. The second scenario investigates the performance of the enhanced-TCP Vegas in multiple TCP connections. The results of simulation experiment show that: (i) as the number of TCP connection in a network increases, the packet delay, network throughput and network efficiency increases; (ii) the throughput fairness increases as the packet size increases. However, as the number of TCP connection increases, the variation of the throughput fairness for all the packet sizes decreases. The proposed algorithm shows poor throughput fairness against standard TCP Vegas algorithm; (iii) as the number of TCP connections in network increase, the handover recovery time increases accordingly. The proposed algorithm exhibits lesser handover recovery time compared to the standard TCP Vegas algorithm; (iv) the appropriate packet size of FTP file is inversely proportional to the number of TCP connection in a network; (v) as the buffer size in a network increases, packet delay, network throughput and network efficiency increases. Additionally, this research presents the appropriate packet size and buffer size to be used over the multiple TCP connections network by using the proposed algorithm.
  • Publication
    Robust and secured data hiding schemes using digital image steganography
    ( 2013)
    Nagham Hamid Abdul Mahdi
    Transmitting data over a public network such as the Internet necessitates increasing the security of data communications; especially with the highly sensitive document transfer. Steganography techniques have been introduced and developed to provide security to these applications. Fundamentally, the steganography goal is not only to hinder the adversary from decoding a hidden message, but also to prevent an adversary from suspecting the existence of covert communications. It does not replace cryptography but rather improves the security using its obscurity features. If one's suspicious is raised while using a steganography technique, the goal of the latter will be defeated regardless whether or not a plaintext is revealed. In this research, two steganography techniques for digital images were developed. The first algorithm provides a new and efficient steganographic system, called Characteristic Region-Based Image Steganography (CR-BIS). It combines both the robustness of Speeded-Up Robust Features technique (SURF) and Discrete Wavelet Transform (DWT) to achieve characteristic region steganography synchronization. It avoids hiding data in the whole image by dynamically selecting characteristic regions for the process of embedding. Such a dynamic manner of region selection increases the security of embedded data. The experimental results showed that CR-BIS provided stego-images with a good perceptual quality; this was indicated by the obtained high Peak Signal to Noise Ratio (PSNR) values, up to 48.30 dB. The second algorithm, namely, an Improved Robust and Secured Steganography (IRSS), is an improvement of Mali et al.’s algorithm, which has a reliability defect as some data cannot be retrieved at the extraction phase. IRSS has overcome the problem of information loss via adopting the concept of the embedding map. Besides, it has been proved experimentally that IRSS outperformed the original one in terms of stego-image quality; this was demonstrated by the achieved PSNR values, which were between (37.28-39.74) dB. In the two proposed algorithms, the embedded secret information can be correctly recovered without referring to the original cover-image. In addition, improving the robustness of the stego-system by Error Correcting Codes (ECC) insertion and adding redundancy bits to the secret embedded message is defined and evaluated, in order to suggest an appropriate robustness enhancing method for the proposed algorithms. As a popular ECC, Reed- Solomon Code (RS-Code) was used to produce correction bits equal to the number of bits produced by a specific redundancy factor. It has been concluded from the experimental results that RS-code improved the robustness of CR-BIS algorithm more than the addition of redundancy does. On the other hand, adding redundancy bits to the message has a much better effect on the robustness of IRSS algorithm.