Journal Articles

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https://hdl.handle.net/20.500.14170/1818

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  • 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).
      8  20
  • 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.
      1  6
  • Publication
    A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems
    (De Gruyter, 2023)
    Aymen Abdalmunam Hameed
    ;
    Anuar Mat Safar
    ;
    Montadar Abas
    ;
    Junita Mohd Nordin
    ;
    Norizan Mohamed Nawawi
    In this paper, we propose a new adaptive layered asymmetrically-clipped optical orthogonal frequency division multiplexing (ALACO-OFDM) technique as a method to improve the spectral efficiency of optical system, especially visible light communication (VLC). Particle swarm optimisation (PSO)-based LACO-OFDM method is used for this purpose and the channel capacities are studied. Simulations using variable layers are carried out to validate the theoretical steps. The simulation results indicate that the ALACO-OFDM technique has significantly improve the spectral efficiency compared to previous techniques such as ACO-OFDM. Moreover, it is shown that channel capacities of different layers are significantly improved when electrical power is increased.
      2  23
  • Publication
    A patch antenna with enhanced gain and bandwidth for sub-6 GHz and sub-7 GHz 5G wireless applications
    (MDPI, 2023)
    Shehab Khan Noor
    ;
    Muzammil Jusoh
    ;
    Ali Hanafiah Rambe
    ;
    Thennarasan Sabapathy
    ;
    Hamsakutty Vettikalladi
    ;
    Ali M. Albishi
    ;
    Mohamed Himdi
    This paper presents a novel microstrip patch antenna design using slots and parasitic strips to operate at the n77 (3.3–4.2 GHz)/n78 (3.3–3.8 GHz) band of sub-6 GHz and n96 (5.9–7.1 GHz) band of sub-7 GHz under 5G New Radio. The proposed antenna is simulated and fabricated using an FR-4 substrate with a relative permittivity of 4.3 and copper of 0.035 mm thickness for the ground and radiating planes. A conventional patch antenna with a slot is also designed and fabricated for comparison. A comprehensive analysis of both designs is carried out to prove the superiority of the proposed antenna over conventional dual-band patch antennas. The proposed antenna achieves a wider bandwidth of 160 MHz at 3.45 GHz and 220 MHz at 5.9 GHz, with gains of 3.83 dBi and 0.576 dBi, respectively, compared to the conventional patch antenna with gains of 2.83 dBi and 0.1 dBi at the two frequencies. Parametric studies are conducted to investigate the effect of the parasitic strip’s width and length on antenna performance. The results of this study have significant implications for the deployment of high-gain compact patch antennas for sub-6 GHz and sub-7 GHz 5G wireless communications and demonstrate the potential of the proposed design to enhance performance and efficiency in these frequency bands.
      16  1
  • Publication
    A Point-of-Care immunosensor for human chorionic gonadotropin in clinical urine samples using a cuneated polysilicon nanogap Lab-on-Chip
    ( 2015)
    S. R. Balakrishnan
    ;
    Uda Hashim
    ;
    Subash Chandra Bose Gopinath
    ;
    Prabakaran A/L Poopalan
    ;
    H. R. Ramayya
    ;
    M. Iqbal Omar
    ;
    R. Haarindraprasad
    ;
    P. Veeradasan
    Human chorionic gonadotropin (hCG), a glycoprotein hormone secreted from the placenta, is a key molecule that indicates pregnancy. Here, we have designed a cost-effective, label-free, in situ point-of-care (POC) immunosensor to estimate hCG using a cuneated 25 nm polysilicon nanogap electrode. A tiny chip with the dimensions of 20.5 × 12.5 mm was fabricated using conventional lithography and size expansion techniques. Furthermore, the sensing surface was functionalized by (3-aminopropyl)triethoxysilane and quantitatively measured the variations in hCG levels from clinically obtained human urine samples. The dielectric properties of the present sensor are shown with a capacitance above 40 nF for samples from pregnant women; it was lower with samples from non-pregnant women. Furthermore, it has been proven that our sensor has a wide linear range of detection, as a sensitivity of 835.88 μA mIU-1 ml-2 cm-2 was attained, and the detection limit was 0.28 mIU/ml (27.78 pg/ml). The dissociation constant Kd of the specific antigen binding to the anti-hCG was calculated as 2.23 ± 0.66 mIU, and the maximum number of binding sites per antigen was Bmax = 22.54 ± 1.46 mIU. The sensing system shown here, with a narrow nanogap, is suitable for high-throughput POC diagnosis, and a single injection can obtain triplicate data or parallel analyses of different targets.
      19  3
  • Publication
    A reconfigurable WiMAX antenna for directional and broadside application
    ( 2013-04-25)
    Muzammil Jusoh
    ;
    M. F. Jamlos
    ;
    M. R. Kamarudin
    ;
    Thennarasan Sabapathy
    A novel reconfigurable compact patch array antenna for directional and broadside application is proposed. The presented antenna has successfully been able to function for directional beam at 320° or 35° and divisive broadside beam at 43° and 330°. This is realized in the unique form of aperture coupled spiral feeding technique and positioning of the radiating elements at 0°, 90,° and 180°. The switchable feature is effectively performed by the configuration of three PIN diodes. All PIN diodes are positioned at the specific location of the aperture coupled structure. It is discovered in simulation that the switches can be represented with a copper strip line or touchstone (TS) block . The proposed antenna design operates at 2.37 GHz to 2.41 GHz and has a maximum gain of 6.4 dB and efficiency of 85.97%. Such antenna produces a broadside HPBW with a wider bandwidth covering from −90° to 90° compared to the normal microstrip antenna which could only provide HPBW of −50° to 50°. Moreover, the proposed antenna has small physical dimension of 100 mm by 100 mm. The simulation and measurement results have successfully exhibited the idea of the presented antenna performance. Therefore, the antenna is sufficiently competent in the smart WiMAX antenna application.
      9  9
  • Publication
    A Review of Antennas for Picosatellite Applications
    ( 2017)
    Abdul Halim Lokman
    ;
    Ping Jack Soh
    ;
    Saidatul Norlyana Azemi
    ;
    Herwansyah Lago
    ;
    Symon K. Podilchak
    ;
    Suramate Chalermwisutkul
    ;
    Mohd Faizal Jamlos
    ;
    Azremi Abdullah Al-Hadi
    ;
    Prayoot Akkaraekthalin
    ;
    Steven Gao
    Cube Satellite (CubeSat) technology is an attractive emerging alternative to conventional satellites in radio astronomy, earth observation, weather forecasting, space research, and communications. Its size, however, poses a more challenging restriction on the circuitry and components as they are expected to be closely spaced and very power efficient. One of the main components that will require careful design for CubeSats is their antennas, as they are needed to be lightweight, small in size, and compact or deployable for larger antennas. This paper presents a review of antennas suitable for picosatellite applications. An overview of the applications of picosatellites will first be explained, prior to a discussion on their antenna requirements. Material and antenna topologies which have been used will be subsequently discussed prior to the presentation of several deployable configurations. Finally, a perspective and future research work on CubeSat antennas will be discussed in the conclusion.
      24  1
  • Publication
    A review of implantable and ingestible antenna for wireless capsule endoscopy system
    (AIP Publishing, 2023)
    Wei Wen Tai
    ;
    Muhammad Solihin Zulkefli
    ;
    Ping Jack Soh
    Wireless medical devices are utilized to obtain physiological signals from the human body to an external monitoring device. The in-body antenna plays a crucial role in ensuring the transmission of physiological signals for implantable or ingestible wireless medical devices. One of the wireless medical devices that involve implantable and ingestible antennas is capsule endoscopy. The implantable one is to be implanted surgically into the human body while the ingestible one is swallowed like a multi-vitamin to perform a wide variety of diagnostic and therapeutic functions in the gastrointestinal (GI) tract. A review of both antennas and their application is presented. Besides, the design of such in-body antenna in the wireless capsule endoscopy especially in current technologies (e.g Wi-Fi, WLAN, Bluetooth, IoT) is extremely challenging and intriguing owing to it deals with the challenges related to the selection of operating frequency band, type of antenna design, and antenna miniaturization technique. Most of the antenna is facing the issue with bandwidth, transmission rate, the robustness of the communication links, size constraint, components arrangement in capsule, and others that could directly affect the patient safety and performance of capsule endoscopy in the human body. Nevertheless, the application of such implantable and ingestible antenna in wireless capsule endoscopy is incessant and rapid growth along with the evolution of technology, thus eliminating any concerns related to the aforementioned challenges and their invasive nature. In this paper, comparative reviews on the design consideration of the in-body antennas are discussed.
      12  2
  • Publication
    A sight of view on electrical impacts, structural properties and surface roughness of tungsten trioxide thin film: effect of substrate temperatures in WO₃/Si device fabrication
    (IOP Publishing, 2023)
    Evan T Salim
    ;
    Azhar I Hassan
    ;
    Farhan A Mohamed
    ;
    Mohamad Halim Abd. Wahid
    ;
    Makram A Fakhri
    Monoclinic WO₃ thin films have been effectively deposited by a simple spray pyrolysis technique at a molar concentration of 0.01 M on a glass substrate in the temperature range of 473 to 673 K. These WO₃ films were used as an interlayer between the metal and the semiconductor, which formed the basic structure of the photodetector. Effect of substrate temperature on WO₃ films during the process of the deposition was systematically interpreted with respect to the structural, morphological, optical and electrical properties of the WO₃ films. The x-ray diffraction pattern revealed the polycrystalline nature of the prepared films with monoclinic phases. At the substrate temperature of 623 K, the nano-thin films were strongly bonded to each other as observed from the FE-SEM images. Visible and ultraviolet spectroscopies indicated the band gap (Eg) of the WO₃ thin film is 3.30 eV. The dc electrical study recorded a sharp increase in the electrical conductivity of the prepared film at substrate temperature of 623 K for tungsten trioxide. It is worth noting that all diodes showed a positive photoresponse under illumination. In particular, the photodetector with the thickness of 300 nm showed higher responsivity 0.02 A/W and detection specificity 8.29 × 1010 Jones.
      9  1
  • Publication
    ABCS antenna for wireless body area network at 26 GHz
    (AIP Publishing Ltd., 2023)
    Muhammad Afifi
    ;
    Saidatul Norlyana Azemi
    ;
    Amiza Amir
    ;
    Soh Ping Jack
    The paper presents the design and investigation of a wearable textile antenna (receiver) and transmitter antenna operating in the wireless body area network (WBAN) of 26 GHz band for 5G mobile networks. The wearable antenna with an overall size of 30 mm x 40 mm x 1.26 mm achieves good impedance matching, high gain, and directive radiation pattern. Both antennas were designed using CST Microwave Studio to validate the simulation results. A rectangular radiating patch comprises a Shieldit electrotextile situated on one side of a non-conductive substrate panel with the ground plane. The bed sheet cotton fabric is used as the non-conductive substrate due to its widespread use in daily clothing with a dielectric constant is 3.2 and the loss tangent is 0.0027. In addition, the wearable antenna successfully achieved the high gain and efficiency of 12 dB and 90.83% respectively. Moreover, the antenna operating at 26 GHz with -40.48 dB return loss, which is less than the -10 dB in requirement. The simulated results show that this proposed wearable antenna is best suited for wireless body area network applications. Hence, the wearable antenna is simple, compact and easy to fabricate.
      1  13
  • Publication
    An Augmented Reality (AR) marker-based application for smart campus: UniMAP residential college
    (Institute of Advanced Scientific Research, 2020)
    Rusnida Romli
    ;
    Sen, Ng Wen
    ;
    Nur Hafizah Ghazali
    ;
    Nik Adilah Hanin Zahri
    Augmented Reality nowadays is getting wide usage with all application in human daily life. This paper of research is about the design and development of Augmented Reality (AR) for smart campus urbanization using the student’s residential college. The technique used in this application is marker-based. Then analyze the efficiency of positioning the object on the right place on display screen with the image processing to get the tag from the image and set as the image marker. The image triggered is analyze either it is projected on the image or slightly change from the actual position. The scope of this research is direct and specific as it will help newcomers or visitor to the hostel area to get information and direction easily with this application. There are many area and information inside as the users should know with the guidance of the application. This research is to make an Android-based application with the interfaces of Augmented Reality to demonstrate and testify the proficiency of virtual data and information shown on the device screen and the feasibility of the augmented object plotted and registered at certain places of hostel. Thus, by using this AR technology to enhance user experience in the hostel area with direction and right information instantly. The contribution of this research trying to reach were those first-time visitors when they arrived at the hostel as there is lack of information for them to locate themselves in such a large campus area and assisting them especially in the term of information and directions. Information is easier and capable to receive by the user as they require only a smart phone to operate the advance feature from the AR application. Furthermore, it does not need any of internet connection in order to use the application and can be operated in offline. With the specified and unique images, users are able to view the virtual object in an entertaining AR environment at the same time better presentation of info can also be delivered.
  • Publication
    An introduction to double stain normalization technique for brain tumour histopathological images
    ( 2024)
    Fahmi Akmal Dzulkifli
    ;
    Mohd Yusoff Mashor
    ;
    Rafikha Aliana A Raof
    ;
    Hasnan Jaafar
    Stain normalization is an image pre-processing method extensively used to standardize multiple variances of staining intensity in histopathology image analysis. Staining variations may occur for several reasons, such as unstandardized protocols while preparing the specimens, using dyes from different manufacturers, and varying parameters set while capturing the digital images. In this study, a double stain normalization technique based on immunohistochemical staining is developed to improve the performance of the conventional Reinhard’s algorithm. The proposed approach began with preparing a target image by applying the contrast-limited adaptive histogram equalization (CLAHE) technique to the targeted cells. Later, the colour distribution of the input image will be matched to the colour distribution of the target image through the linear transformation process. In this study, the power-law transformation was applied to address the over-enhancement and contrast degradation issues in the conventional method. Five quality metrics comprised of entropy, tenengrad criterion (TEN), mean square error (MSE), structural similarity index (SSIM) and correlation coefficient were used to measure the performance of the proposed system. The experimental results demonstrate that the proposed method outperformed all conventional techniques. The proposed method achieved the highest average values of 5.59, 3854.11 and 94.65 for entropy, TEN, and MSE analyses.
      1  19
  • Publication
    Android-based timetable manager for university students using rule-based algorithm
    (AIP Publishing Ltd., 2023)
    Lim Yan Yi
    ;
    Norfadila Mahrom
    ;
    Calvin Lim
    Currently, there are several drawbacks in the existing university timetable system, including students do not know the class hour of subjects that they are going to register during the registration period. This situation has resulting in clashing in the class hour of the registered subjects. In addition, some students are not aware of this situation until it is too late from them to drop and register other subjects. This particularly happened to those who has more than two registered subjects clash and resulting in overlook at the rest of clashed subjects. Besides, students find it is inconvenient to view the timetable through the current timetable system. Thus, the development of an Android based mobile application that able to notify students if the class hour of the subjects they registered are overlapping is presented in this paper. The application also able to manage the student timetable by reporting details such as venue, day and the time of clashed subjects. Then, the application will suggest student to select elective subjects or subjects that students wish to retake to prevent clashing in class hour. The software development of the application is based on the Agile model and using rule-based algorithm. The application is developed in Android Studio by using Java as the programming language and all data is stored in Firebase Realtime Database. In conclusion, this paper presents results of the application that has successfully designed and developed.
      2  13
  • Publication
    Camera motion estimation and object extraction using multiple consecutive frames with ghost and noise removal for Pan-Tilt-Zoom camera
    ( 2014)
    Syaimaa' Solehah Mohd Radzi
    This research presents a new algorithm for extracting moving objects using Pan-Tilt- Zoom (PTZ) camera. Previously, system that uses moving camera faces some problems, including misalignment between current and template frames, appearance of unwanted objects (ghost), illumination changes, shadow and crowd. This research developed an algorithm to avoid misalignment images, remove ghost and noises. The proposed algorithm consists of six steps, which are camera motion estimation, object extraction, removing ghost, detecting shadow, refining shadow and noises elimination. This research proposed to apply camera motion estimation twice, which is between three consecutive frames. Keypoints of each image are detected using Speed-up Robust Features (SURF) detector, then produces homography matrix. The homography contains rotation and translation of one image from another image. It is used to warp previous frames with respect to the current frame. In object extraction, current frame is compared to both compensated previous frame 1 and compensated previous frame 2 using Wronskian Change Detector (WCD). Detecting changes using multiple frames produces ghost, which is actually moving objects in previous frames. Then, this research has developed a ghost removal technique, in which two output images of object extraction are compared each other, pixel by pixel. Then the existing method of shadow removal, Normalized Cross-Correlation (NCC) technique is applied to refine the output image. Some pixels may be misclassified as shadow pixels. Therefore, refinement of shadow detection is done so that the actual shadow is removed, while the false detected shadows are returned to be background entities. To remove other noises, a 3x3 noise filter has been created. The filter is used to scan the output image where the centre of the 3x3 window will look for white pixel. Number of white pixel in the whole window (filter) will be compared to the threshold. Finally, morphological operator is used to remove undesirable foreground pixels. The developed algorithm had been tested on seven image conditions; striped background, objects move slowly, camouflage object, small moving object, multiple moving objects, objects move towards the camera and shadow. The developed algorithm has successfully extracted moving object, removed ghost, removed shadow, noises and detected illumination changes. Based on the manual calculation and visual observations, this system has the highest average accuracy which is 95.13%, followed by single WCD 93.99%, Background Subtraction 93.42%, Luminance Ratio 92.92%, HSV Histogram 91.85% and Greyscale Histogram 91.47%.
      11  1
  • Publication
    Characterization of doped ZnO thin film for Ammonia gas sensing application
    (Institute of Physics, Polish Academy of Sciences, 2023)
    Shazlina Johari
    ;
    Fatin Amira Hasbullah
    ;
    Anis Syafiqa Rosman
    ;
    Muhammad Mahyiddin Ramli
    ;
    Mohd Fairus Ahmad
    ;
    Norizah Abd Karim
    ;
    Nurul Huda Osman
    ;
    D. Darminto
    ;
    Ali Hussain Reshak
    ;
    Sebastian Garus
    This paper reports on the characterization of Sn- and Al-doped zinc oxide thin film for potential ammonia gas detection. The sol–gel method has been used to deposit the dopant onto the glass substrate at an annealing temperature of 500◦C for three different doping concentrations, which are 0.5, 1.0, and 1.5 at.%. The method used to produce this thin film is sol–gel, as it is cheap, easy, and can be employed at low temperatures. The studies involve the investigation of the morphological structures and electrical and optical properties of doped ZnO. In terms of structural properties, scanning electron microscope images of Sn- and Al-doped ZnO change as the dopant concentration is increased. The doped thin film response and recovery towards 200 ppm of ammonia were observed and recorded. Both dopants show good gas sensing response. The recorded resistance reading suggests that Al is the superior dopant in gas sensing as it produces a low resistance reading of 230 Ω as opposed to 140 kΩ produced by Sn-doped ZnO thin film.
  • Publication
    Coconut shell, coconut shell activated carbon and beta-silicon carbide reinforced polymer composite: an alternative dielectric material for wireless communication application
    (Institute of Advanced Engineering and Science (IAES), 2020)
    Been Seok Yew
    ;
    Martini Muhamad
    ;
    Saiful Bahri Mohamed
    ;
    Wee Fwen Hoon
    The effect of coconut shell (CS), coconut shell activated carbon (CSAC) and beta-silicon carbide (β-SiC) in polymer composites was investigated. Elemental composition, surface morphologies and structural analyses of the fillers were performed using carbon, hydrogen, nitrogen and sulfur (CHNS) analyser, scanning electron microscope (SEM) and X-ray Diffractometer (XRD). The dielectric properties of the composites were measured using open-ended coaxial line method. CS and CSAC fillers had positive influence on the dielectric properties (ε’, ε” and σ) of the polymer composites, contributed by the orientation polarizations arises from polar nature of the amorphous CS and CSAC fillers. β-SiC filler had insignificant influence on the dielectric properties of the polymer composites due to its single polarization of the crystalline structure filler. This finding is in agreement with XRD patterns of CS and CSAC fillers that revealed the presence of amorphous structure with broad diffraction peaks that were detected at 2ϴ=22.236°, 34.8604° and 2ϴ=23.985° and 44.015°, respectively. The amorphization structure in the polymer composites allows the displacement and conduction currents that were induced from electric field to flow through the polymer composites when subjected to electromagnetic energy, thus increased the dielectric properties of the composites.
      8  1
  • Publication
    Colossal permittivity and dielectric behaviour of (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ and (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramics
    (Springer Nature, 2023)
    Ku Noor Dhaniah Ku Muhsen
    ;
    Rozana Aina Maulat Osman
    ;
    Mohd Sobri Idris
    The influence of pentavalent elements (Nb⁵⁺, Ta⁵⁺) with Fe³⁺ on TiO₂ ceramic were investigated. The (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ and (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramics have been synthesized and realized that the effect of Nb in the system has developed lattice expansion, although Nb and Ta exhibit similar ionic radii. The colossal permittivity value for (Nb₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramic is about εr ≥ 104 which is slightly higher than the (Ta₀.₅Fe₀.₅)₀.₁Ti₀.₉O₂ ceramic. According to the dielectric analysis, both ceramics exhibit colossal permittivity below 10³ Hz which contributed by the electron-pinned defect-dipole (EPDD) model. However, the low εr values in the high-frequency region are associated with the internal barrier layer capacitor (IBLC) model. In addition, the grain boundary resistance is far greater than the grain resistivity (Rgb≫ Rg) which confirmed the existence of the IBLC effect by equivalent circuit analysis.
  • Publication
    Comparative analysis of image processing techniques for enhanced MRI image quality: 3D reconstruction and segmentation using 3D U-Net architecture
    (MDPI, 2023)
    Lim Chee Chin
    ;
    Apple Ho Wei Ling
    ;
    Yen Fook Chong
    ;
    Mohd Yusoff Mashor
    ;
    Khalilalrahman Alshantti
    ;
    Mohd Ezane Aziz
    Osteosarcoma is a common type of bone tumor, particularly prevalent in children and adolescents between the ages of 5 and 25 who are experiencing growth spurts during puberty. Manual delineation of tumor regions in MRI images can be laborious and time-consuming, and results may be subjective and difficult to replicate. Therefore, a convolutional neural network (CNN) was developed to automatically segment osteosarcoma cancerous cells in three types of MRI images. The study consisted of five main stages. First, 3692 DICOM format MRI images were acquired from 46 patients, including T1-weighted, T2-weighted, and T1-weighted with injection of Gadolinium (T1W + Gd) images. Contrast stretching and median filter were applied to enhance image intensity and remove noise, and the pre-processed images were reconstructed into NIfTI format files for deep learning. The MRI images were then transformed to fit the CNN’s requirements. A 3D U-Net architecture was proposed with optimized parameters to build an automatic segmentation model capable of segmenting osteosarcoma from the MRI images. The 3D U-Net segmentation model achieved excellent results, with mean dice similarity coefficients (DSC) of 83.75%, 85.45%, and 87.62% for T1W, T2W, and T1W + Gd images, respectively. However, the study found that the proposed method had some limitations, including poorly defined borders, missing lesion portions, and other confounding factors. In summary, an automatic segmentation method based on a CNN has been developed to address the challenge of manually segmenting osteosarcoma cancerous cells in MRI images. While the proposed method showed promise, the study revealed limitations that need to be addressed to improve its efficacy.
      16  1
  • Publication
    Comparative analysis on virtual private network in the internet of things gateways
    ( 2022-10-01)
    Mohd Idzaney Zakaria
    ;
    Mohd Natashah Norizan
    ;
    Muammar Mohamad Isa
    ;
    Mohd Faizal Jamlos
    ;
    Mustapa Muslim
    A virtual private network (VPN) connects a private network to the internet, primarily the public network, through a secure tunnel. Using a local area network (LAN) segment, users can send and receive data from their colleagues in different locations on the network. The development of VPN allows users to gain access to company applications and databases. Therefore, data can be transmitted through a secure tunnel without the need to configure port forwarding for the internet of things (IoT) gateway, allowing users to access it from any location in the world. A method such as dataplicity and pitunnel was examined to compare with the conventional setting. This research paper examines the current deployment of VPN connections in IoT gateways, discussing their characteristics, benefits, and drawbacks, as well as comparing them. The advantage of this method is that the IoT gateway is always accessible and has internet connectivity, which is a significant benefit. Dataplicity is a more trustworthy option because they offer excellent assistance for both the backend and frontend environments.
      1  14
  • Publication
    Comparison between conventional OCDMA and subcarrier multiplexing SAC OCDMA system based on single photodiode detection
    ( 2017-12-11)
    N. A. A Ahmad
    ;
    Junita Mohd Nordin
    ;
    Syed Alwee Aljunid Syed Junid
    ;
    Mohd Rashidi Che Beson
    ;
    Rosdisham Endut
    This paper demonstrates the comparison between conventional OCDMA system and subcarrier multiplexing (SCM) SAC-OCDMA system by applying Recursive Combinatorial (RC) code based on single photodiode detection (SPD). SPD is used in the receiver part to reduce the effect of multiple access interference (MAI) which contributes as a dominant noise in incoherent SAC-OCDMA systems. From this analysis, the performance of SCM OCDMA network could be improved by using lower data rates and higher received power. The hybrid SCM OCDMA system shows better performance compare to conventional OCDMA system although the number of users involved is very high. This is because, for hybrid SCM OCDMA system, the number of users can be increased by increasing the number of subcarriers without affect the number of code length and optical codes. Increasing the number of subcarriers will enhance the power consumption by applying hybrid SCM system in OCDMA compared to the conventional OCDMA system. This is because increasing the number of users for hybrid SCM system does not affects the number of code length and the number of optical codes but only increase the number of subcarriers. Thus, hybrid SCM OCDMA system has to increase spectral efficiency and produce better performance compared to conventional of OCDMA system
      1  16