Now showing 1 - 9 of 9
  • Publication
    Compact Meandered Monopole Antenna for Dual-Bands WLAN Application
    ( 2021-07-26)
    Bohari S.
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    Faudzi N.M.
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    Razali A.R.
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    Mozi A.M.
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    A compact meandered dual-bands monopole antenna for the application of a wireless local area network (WLAN) is proposed. This antenna has two operating frequency bands which are 2.4 GHz and 5.2 GHz and denoted as lower and upper operating bands respectively. In the antenna design, a meandered arms structure has been proposed to obtain a compact size monopole antenna with an overall dimension of 30 mm x 21 mm. Furthermore, the dual-bands operating frequency is achieved with the contribution of two meandered arms structure as well as a partial ground plane proposed in the antenna design. The copper layer traces with the thickness of 0.035 mm has been used as the radiating patch and the partial ground plane has been printed at the back side of the FR-4 substrate with the permittivity, ϵ_r of 4.5 and the thickness of 1.6 mm. The proposed antenna has a simple design, small size, easy to fabricate and low cost. The measured and simulated results were compared to analyse the performance of the designed antenna. From the simulation, the operating frequencies achieved are at 2.44 GHz and 5.23 GHz, while from the measurement at 2.50 GHz and 4.44 GHz. Other antenna parameter such as radiation pattern and gain has also been evaluated and analysed.
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  • Publication
    Parametric studies on effects of defected ground structure (DGS) for dual band bandstop microstrip filter
    A dual-band bandstop microstrip filter is proposed and designed by using microstrip resonator with Defected Ground Structure (DGS). The DGS are placed in the ground plane to obtain high attenuation of the bandstop filter response. The proposed is designed by using R04003C printed circuit board with dimension of 38 mm x 20 mm. Simulated result shows an insertion loss of -12.31 dB, a return loss at -1.75 dB for center frequency at 2.4 GHz and insertion loss of -22.93 dB, a return loss of -0.78 dB for center frequency at 5.8 GHz The results of simulated in different parameters of DGS is analysed and discussed.
  • Publication
    Traffic engineering provisioning of multipath link failure recovery in distributed SDN controller environment
    ( 2024-02-08)
    Kelian V.H.
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    Mohd Warip M.N.
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    Ehkan P.
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    A revolutionary networking technology called Software-Defined Networking (SDN) enables better networking flexibility. In contrast to the conventional network, it provides another option for network development. SDN is characterized by the separation of the control and data planes in network architecture, implementation, and management. The central component of the network is the controller, which constitutes the control plane. The appropriate selection of a controller, along with determining the number and placement of controllers, plays a crucial role in optimizing resource utilization and guaranteeing network availability and network performance. Since SDN is still in its beginnings of development, it is virtually certain that further study will be needed in areas like design, particularly on the control plane, since the architecture directly affects the network's total performance. Furthermore, despite its intended purpose of managing networks on a large scale, SDN still presents challenges in effectively addressing network dynamics, such as the occurrence of link failures. This study presents a concept for the implementation of an SDN architecture. The proposed approach involves utilizing an Open Network Operating System (ONOS) open-source distributed SDN controller. The purpose of this implementation is to analyze network performance metrics and assess network availability. This study investigates the distributed SDN controller's performance on different scale networks: NSF, AEON, and TM topologies. Several metrics have been analyzed, including throughput, link failure detection, and Round-Trip-Time (RTT). The experiments use Mininet for emulation and Wireshark for real-time data packet capture and analysis. According to the study results, there is a positive correlation between network design complexity and controller load. The experiment emphasizes the resilience of distributed controllers, such as ONOS, in effectively recovering from link failures. This research will help academics and businesspeople who use distributed SDN controllers choose a controller and evaluate its effectiveness on the analyzed network architectures.
  • Publication
    Comparative Study of Parallelism and Pipelining of RGB to HSL Colour Space Conversion Architecture on FPGA
    ( 2020-03-20)
    Pakhlen Ehkan
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    Siew, Soon Voon
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    RGB colour model is a basic colour model and complements together to produce full colour range but it is unable to produce sufficient information for digital image analysis. However, HSL is capable to provide other useful information such as colour in degree, saturation of the colour and brightness of colour. In this work, RGB to HSL mathematical conversion algorithm is implemented on FPGA chip. Parallelism and pipelining capabilities of FPGA helps to speed up conversion performance. The RGB to HSL equation is implemented by using two architectures which are parallel and 7-stages pipeline architectures. The designed parallel and pipeline converters have one clock and seven clock cycle of data latency respectively. The parallel and pipeline architectures for RGB to HSL converter have been achieved rate of accuracy by hardware verification up to 99% and 98% and possessed maximum operating frequency merit of 50 MHz and 120 MHz respectively.
  • Publication
    The Performance Analysis of K-Nearest Neighbors (K-NN) Algorithm for Motor Imagery Classification Based on EEG Signal
    ( 2017-12-11)
    Nurul E’zzati Md Isa
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    Most EEG-based motor imagery classification research focuses on the feature extraction phase of machine learning, neglecting the crucial part for accurate classification which is the classification. In contrast, this paper concentrates on the classifier development where it thoroughly studies the performance analysis of k-Nearest Neighbour (k-NN) classifier on EEG data. In the literature, the Euclidean distance metric is routinely applied for EEG data classification. However, no thorough study has been conducted to evaluate the effect of other distance metrics to the classification accuracy. Therefore, this paper studies the effectiveness of five distance metrics of k-NN: Manhattan, Euclidean, Minkowski, Chebychev and Hamming. The experiment shows that the distance computations that provides the highest classification accuracy is the Minkowski distance with 70.08%. Hence, this demonstrates the significant effect of distance metrics to the k-NN accuracy where the Minknowski distance gives higher accuracy compared to the Euclidean. Our result also shows that the accuracy of k-NN is comparable to Support Vector Machine (SVM) with lower complexity for EEG classification.
  • Publication
    Deep-Learning Assisting Cerebral Palsy Patient Handgrip Task Translation
    ( 2021-07-26) ; ;
    Phaklen Ehkan
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    Muslim Mustapa
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    An electro-encephalography (EEG) brain-computer interface (BCI) can provide the brain and external environment with separate information sharing and control networks. EEG impulses, though, come from many electrodes, which produce different characteristics, and how the electrodes and features to enhance classification efficiency have been chosen has become an urgent concern. This paper explores the deep convolutional neural network architecture (CNN) hyper-parameters with separating temporal and spatial filters without any pre-processing or artificial extraction processes. It selects the raw EEG signal of electrode pairs over the cortical area as hybrid samples. Our proposed deep-learning model outperforms other neural network models previously applied to this dataset in training time (∼40%) and accuracy (∼6%). Besides, considerations such as optimum order for EEG channels do not limit our model, and it is patient-invariant. The impact of network architecture on decoder output and training time is further discussed.
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  • Publication
    Parametric analysis on the effect of open circuit stub resonator towards the performance of ultra-wideband stepped impedance low pass filter
    This paper presents the parametric studies on the effect of open circuit stub resonator (OCSR) towards the performance of Chebyshev Ultra-Wideband Stepped Impedance Low Pass Filter (SILPF). The SILPF is realized by loading OCSR to the high impedance line of the main design in order to overcome the drawback of conventional SILPF. The filter can produce sharp transition band and also wide stopband bandwidth. The design of SILPF is based on 5th order Chebyshev with 0.1 dB ripple. The filter is designed to operate at cut-off frequency 7.30 GHz. By investigating the effect of varying dimension of OSCR’s selected parameters, this paper is able to highlight the susceptibility of modifying cut-off frequency, fc and also transmission zeroes frequency, fz in order to be used for different applications. Thus, the combination of SILPF and OCSR and also rectangular patch combined feed-line structure exhibits wide rejection bandwidth better than −20 dB from 8.20 GHz up to 23.38 GHz. The filter design is simulated on Roger 4003 with relative dielectric constant, εr of 3.38 and also the substrate thickness, h of 0.508. This proposed simulated filter design has shown promising result and could be further analyzed for experimental works and fabrication. Therefore, the filter is beneficial for communication and radar systems particularly to avoid the interference and harmonic as well as the spurious response signals.
  • Publication
    Design of C-band Low-noise Amplifier (LNA) Using E-pHEMT Device for Satellite Communication System
    A low-noise amplifier (LNA) plays an indispensable role in a communication system for amplification purposes at the transceiver. LNA design in radio frequency (RF) circuits involve various key attributes, namely noise figure (NF), gain, and power consumption. This paper focuses on the design of a C-band LNA for satellite communication system with a centre frequency of 6 GHz using ATF-55143 enhancement-mode pseudomorphic high-electron-mobility transistor (E-pHEMT) technology. The LNA performance is augmented by adding inductors to the drain and gate of the ATF-55143 transistor. Smith chart impedance matching technique is implemented to foster a more precise matching for input and output of the LNA. In this work, the C-band LNA is biased at VDS of 2.7 V and IDS of 10 mA. Electromagnetic (EM) software is used to design and simulate the performance of the LNA circuit layout. Simulation results indicate NF of 2.66 dB and power gain (S21) of 12.29 dB. The LNA consumes 27 mW from a 3 V DC supply.
  • Publication
    Toward Adaptive and Scalable Topology in Distributed SDN Controller
    The increasing need for automated networking platforms like the Internet of Things, as well as network services like cloud computing, big data applications, wireless networks, mobile Internet, and virtualization, has driven existing networks to their limitations. Software-defined network (SDN) is a new modern programmable network architectural technology that allows network administrators to control the entire network consistently and logically centralized in software-based controllers and network devices become just simple packet forwarding devices. The controller that is the network's brain, is mostly based on the OpenFlow protocol and has distinct characteristics that vary depending on the programming language. Its function is to control network traffic and increase network resource efficiency. Therefore, selecting the right controllers and monitoring their performance to increase resource usage and enhance network performance metrics is required. For network performance metrics analysis, the study proposes an implementation of SDN architecture utilizing an open-source OpenDaylight (ODL) distributed SDN controller. The proposed work evaluates the deployment of distributed SDN controller performance on three distinct customized network topologies based on SDN architecture for node-to-node performance metrics such as delay, throughput, packet loss, and bandwidth use. The experiments are conducted using the Mininet emulation tool. Wireshark is used to collect and analyse packets in real-time. The results obtained from the comparison of networks are presented to provide useful guidelines for SDN research and deployment initiatives.
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