Azizi Harun
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Preferred name
Azizi Harun
Official Name
Azizi, Harun
Alternative Name
Harun, Azizi
Harun, A.
Bin Harun, Azizi
Main Affiliation
Scopus Author ID
15063856600
Researcher ID
V-6892-2019

Research Output

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  • Publication
    Signal propagation analysis for low data rate wireless sensor network applications in sport grounds and on roads
    ( 2012)
    David L. Ndzi
    ;
    M. A. Mohd Arif
    ;
    Ali Yeon Md Shakaff
    ;
    Mohd Noor Ahmad
    ;
    Azizi Harun
    ;
    Latifah Munirah Kamarudin
    ;
    Ammar Zakaria
    ;
    Mohd F. Ramli
    ;
    Mohammad Shahrazel Razalli
    This paper presents results of a study to characterise wire- less point-to-point channel for wireless sensor networks applications in sport hard court arenas, grass fields and on roads. Antenna height and orientation effects on coverage are also studied and results show that for omni-directional patch antenna, node range is reduced by a factor of 2 when the antenna orientation is changed from vertical to horizontal. The maximum range for a wireless node on a hard court sport arena has been determined to be 70m for 0dBm transmission but this reduces to 60m on a road surface and to 50m on a grass field. For horizontal antenna orientation the range on the road is longer than on the sport court which shows that scattered signal components from the rougher road surface combine to extend the communication range. The channels investigated showed that packet error ratio (PER) is dominated by large-scale, rather than small-scale, channel fading with an abrupt transition from low PER to 100% PER. Results also show that large-scale received signal power can be modeled with a 2nd or der log-distance polynomial equation on the sport court and road, but a 1st order model is sufficient for the grassfield. Small-scale signal variations have been found to have a Rice distribution for signal to noise ratio levels greater than 10 dB but the Rice K-factor exhibits significant variations at short distances which can be attributed to the influence of strong ground reflections.
  • Publication
    Design of 5 V DC to 20 V DC switching regulator for power supply module
    ( 2017)
    Nor Afiqah Azmi
    ;
    Sohiful Anuar Zainol Murad
    ;
    Azizi Harun
    ;
    Rizalafande Che Ismail
    ;
    Mohd Nazrin Md Isa
    ;
    M. A. Zulkifeli
    This paper presents the design of 5 V to 20 V DC switching regulator for power supply module. A voltage multiplier which consists of cascaded diode-capacitor combination is used in order to obtain a high voltage power supply. Due to power loss that has occurred in a stray of component arrangement, the proposed design employs a pulse width modulation (PWM) controller circuit with an inclusion of a capacitor, diode, and inductor components. The input supply of 5 V DC to LT1618 controller circuit has produced 20.35 V based from simulation results. Meanwhile, the measurement results of 19.36 V are obtained and the feedback signal is required for the purpose of stabilizing the output. The proposed design can reduce the components as well as the PCB size, thus minimizing the overall cost of making a switching regulator for power supply module. © 2017 Author(s).
  • Publication
    Signal propagation modelling for vehicle-to-infrastructure communication under the influence of metal obstruction
    ( 2021-12)
    Jamie Siregar Cynthia Turner
    ;
    Shahriman Abu Bakar
    ;
    Azizi Harun
    ;
    Mohd Sani Mohamad Hashim
    ;
    Zuradzman Mohamad Razlan
    ;
    D L Ndzi
    ;
    Rizalafande Che Ismail
    ;
    Sohiful Anuar Zainol Murad
    ;
    Mohd Nazrin Md Isa
    ;
    Shaiful Nizam Mohyar
    ;
    Mohammad Fadzli Ramli
    ;
    M K N Zulkifli
    Connected car has become one of emerging technology in the automotive industries today. This development preludes a rise in vehicular communication studies that primarily targets radio channel modelling on vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication mode. Considering vehicular obstruction, vast channel propagation studies have focused more on V2V mode while others consider the typical urban scenarios consisting of high traffic volumes of moving vehicles. Due to challenging propagation mechanisms and high complexity in such areas, radio propagation models applied in simulators assume an obstacle-free environment rather than considering the least effect imposed by metal obstruction on communication signal. Besides, there are limited studies pertaining to metal obstruction that considers several under-explored environments such as actual parking lots, junctions and other road infrastructure support. As such, this paper demonstrates signal attenuation analysis caused by the presence of metal objects in low density over obstacle-free environment on actual parking lot via V2I mode. Two scenarios such as LOS and NLOS conditions consisting of obstacle-free, cars and buses as static metal objects are evaluated. The aim of this research is to characterize signal strength caused by metal blockage on radio wave propagation predicated on the presence of vehicles as a subject of obstruction in comparison to obstacle-free vehicular environment. The validity of data is shown through received signal strength indicator (RSSI) and approximation analysis (RMSE) to demonstrate the efficiency of obtained measurements. The results demonstrated that Log-normal shadowing model yields the best fit to low-density metal obstruction scenario with smallest RMSE of 4.78 under bus obstruction whereas 5.72 under car obstruction.
  • Publication
    Electrical conductivity (EC) sensing system for paddy plant using the internet of things (IoT) connectivity
    ( 2020-01-08)
    Othaman N.N.C.
    ;
    Mohd Nazrin Md Isa
    ;
    Sohiful Anuar Zainol Murad
    ;
    Azizi Harun
    ;
    Shaiful Nizam Mohyar
    This paper presents the design and development of an IoT-based electrical conductivity system for measuring paddy soil nutrients. Relationship between electrical conductivity (EC) and the influence of soil temperature in precision farming will be discussed. In this work, the EC algorithm was modelled and verified using MATLAB and realized on Node MCU (ESP8266) microcontroller. Results showed that the measured data from the developed system is closed to the calibration solution conductivity that is 1.413mS/cm and 12.88mS/cm. It is also noted that the recorded electrical conductivity value increases with temperature.
  • Publication
    Speed and Area Efficient FXP Adders and Multipliers: A Comparative Analysis for LNS System
    ( 2020-12-18)
    Basir M.S.S.M.
    ;
    Rizalafande Che Ismail
    ;
    Siti Zarina Md Naziri
    ;
    Mohd Nazrin Md Isa
    ;
    Sohiful Anuar Zainol Murad
    ;
    Azizi Harun
    In this paper, a variety of adder and multiplier are compared to be implemented in a new logarithmic number system (LNS). Both adder and multiplier are designed with a generic very high-speed integrated circuit hardware description language (Verilog) program. This makes it possible to achieve the optimum performance in latency and area of 0.18µm CMOS technologies LNS chip. Consequently, the optimal configurations vary with speed and area of the schemes and in some cases can be compact area, O(n), fast in latency O(log2 n) or optimized. The program was scripted based on fixed-point (FXP) adders and multipliers that yet will be implemented in LNS system. The functionality of the scheme was tested before synthesized. Outcomes show that Ladner Fisher (LF) adder and modified Baugh Wooley multiplier contribute to fast in latency and consume minimal area.
      4  11
  • Publication
    Investigating the thermal characteristic of copper alloys valve seat towards engine performance enhancement of MODENAS CT115 through steady-state analysis
    ( 2021-10-25)
    Zainol M.A.A.
    ;
    Mohamad Aniq Syazwan Mohamed Hassan
    ;
    Shahriman Abu Bakar
    ;
    Zuradzman Mohamad Razlan
    ;
    Anas Abdul Rahman
    ;
    Mohd Sani Mohamad Hashim
    ;
    Nur Saifullah Kamarrudin
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Azizi Harun
    ;
    Ishak Ibrahim
    ;
    Mohd Khairul Faizi Abd Rahman
    ;
    Muhammad Faiz Hilmi Rani
    MODENAS CT115 engine is a single overhead camshaft (SOHC) engine, with a rated power of 8.8 horsepower at 9000 rpm. One of the main concerns of engine research is the overheating of engines. Overheating can affects the performance of an engine by leading to a loss of strength and thermal strain. To prevent failure, thermal analysis is used to determine the flow of heat with precision to optimise temperature distribution. The investigation is done using ANSYS Thermal simulation on the CAD model of the engine cylinder head, intake and exhaust valve, and intake and exhaust valve seat insert. The comparison to the existing valve seat insert is made using three different valve seat insert materials: Beryllium-copper C17200, Bronze-copper C61300, and Brass C36000. The research results proved that Brass C36000 provides the best thermal reduction and heat transfer increment compared to the existing valve seat insert material.
      1  24
  • Publication
    Engine performance enhancement by improving heat transfer in between exhaust valve and valve seat through CFD (transient thermal) simulation
    ( 2021-05-03)
    Mohamad Aniq Syazwan Mohamed Hassan
    ;
    Shahriman Abu Bakar
    ;
    Zuradzman Mohamad Razlan
    ;
    Nur Saifullah Kamarrudin
    ;
    Aziz I.A.
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Mohd Sani Mohamad Hashim
    ;
    Azizi Harun
    ;
    Ishak Ibrahim
    ;
    Ibrahim Z.
    ;
    Mohd Khairul Faizi Abd Rahman
    ;
    Muhammad Faiz Hilmi Rani
    ;
    Rishan Murali
    The combustion of the internal combustion engine results in high heat and pressure produce as exhaust gas. The high-temperature exhaust gas will transfer the heat to surrounding via convection, conduction, and radiation. In the combustion chamber, the exhaust valve and its seat will reach high temperatures due to hot gases exit through the engine exhaust port. This high temperature must be reduced to avoid damaging the engine. In this project, the existing material of the valve seat is tested using computational fluid dynamics simulation for heat analysis. Simulation of transient thermal is conducted to study the detailed behavior of heat transfer of the valve and valve seat in the engine. Four copper-based material of the valve seat is selected which is beryllium copper, chromium copper, brass, bronze are simulated. In the simulation, the brass valve seat has the highest heat absorbance rate which averagely 30% higher than cast iron valve seat in terms of temperature differences. Most of the copper-based valve seat can absorb averagely 10% to 30% more heat than cast iron valve seat depends on the material's thermal conductivity.
      3  17
  • Publication
    Effect of roadways plantation on signal propagation analysis in connected autonomous vehicle communication
    ( 2019)
    J S C Turner
    ;
    Shahriman Abu Bakar
    ;
    Azizi Harun
    ;
    Mohd Sani Mohamad Hashim
    ;
    Zuradzman Mohamad Razlan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Zunaidi Ibrahim
    ;
    Abu Hassan Abdullah
    ;
    M A Fadzilla
    ;
    K A A Kassim
    ;
    M S A Khalid
    ;
    Z Jawi
    ;
    M H M Isa
    ;
    S A Z Murad
    ;
    Rizalafande Che Ismail
    At present, the development of autonomous vehicle has altered the outlook of modern transportation worldwide. The state-of-the-art vehicular communication for transportation system is advancing, especially in vehicle to infrastructure (V2I) communication. An effective communication between vehicle and infrastructure has become a significant part of autonomous transportation criteria. The necessity for high quality of service communication inspire for good planning and preparation in communication process. Per se, this paper proposes vegetation attenuation models for advance planning of communication process between vehicle to infrastructure, defined mainly by plants, trees and vegetation along the roadways in Malaysia. The channel measurement performed in Universiti Malaysia Perlis test-bed having large tall trees and low shrubs along the routes resulted in several interesting results which would shape the planning of CAV communication. It is observed that communication close to low plantation or shrub requires high power consumption as the range is significantly reduced. It is also learned that certain types of plantations allows for different level of signal attenuation depending on the antenna heights. The research also found out that the attenuation profile follows strictly the log normal distribution and as such certain planning could be made to reshape the communication process to cater for this.
      2  23
  • Publication
    Integration of asset tracking system through trilateration method as detection mechanism
    ( 2019)
    M A Fadzilla
    ;
    Shahriman Abu Bakar
    ;
    Azizi Harun
    ;
    Mohd Sani Mohamad Hashim
    ;
    Zuradzman Mohamad Razlan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Z. Ibrahim
    ;
    Abu Hassan Abdullah
    ;
    J.S.C Turner
    ;
    K.A.A Kassim
    ;
    M.S.A Khalid
    ;
    Z. Jawi
    ;
    M.H.M Isa
    ;
    Rizalafande Che Ismail
    Demands for localization system has been growing rapidly in the last several years both for an outdoor and indoor area. In conjunction with this, the capability and reliability of this system to precisely locate and track objects of interest for the indoor area has catered researchers and study on how to do so. One of the major ideas on making it more advance is by incorporating the use of wireless devices into the system. There are numbers of issues that could interrupt the efficiency and success of the system. One of the main problems is the signal loss mainly caused by the attenuation of the signal as they propagate through from the transmitter to the receiver. These attenuations are mostly due to the surface types the signal are traveling on and the objects that are in the Line of Sight in between the transmitter and receiver. In order to ensure the most reliable and efficient wireless connection between transmitter and receiver, a propagation study on the signal is needed for us to analyze and find the best way to trade off the signal attenuation based on the environment surrounding the system. By doing so, a thorough system that has models that can work efficiently even if we are to consider the attenuation factors. The system consists of nodes installed inside the research institute that acts as both transmitter and receivers. The transmitter and receiver will then process the signal that will then determine their location. The receiver is connected to the laptop in order to get a real-time reading so that we will be able to locate the transmitter. A networked of nodes are installed inside the research institute for experiment and the layout of the research is conferred for future references. Data from the experiment are then analyzed and a model for the signal propagation alongside the research institute is created. This model will be able to apprehend the signal attenuation despite the surrounding environment such as furniture and walls. A completed asset tracking system with models of signal attenuation will be built in the future for a more efficient signal transmission.
      25  2
  • Publication
    Signal propagation in aquaculture environment for wireless sensor network applications
    ( 2012)
    Azizi Harun
    ;
    David Lorater Ndzi
    ;
    Mohd F. Ramli
    ;
    Ali Yeon Md Shakaff
    ;
    Mohd Noor Ahmad
    ;
    Latifah Munirah Kamarudin
    ;
    Ammar Zakaria
    ;
    Yanyan Yang
    This paper presents results of signal propagation studies for wireless sensor network planning in aquaculture environment for water quality and changes in water characteristics monitoring. Some water pollutants can cause widespread damage to marine life within a very short time period and thus wireless sensor network reliability is more critical than in crop farming. This paper shows that network coverage models and assumptions over land do not readily apply in tropical aquaculture environment where high temperatures are experienced during the day. More specifically, due to high humidity caused by evaporation, network coverage at 15 cm antenna height is better than at 5 m antenna heights due to the presence of a superrefraction (ducting) layer. For a 69 m link, the difference between the signal strength measured over several days is more than 7 dBm except under anomaly conditions. In this environment, the two-ray model has been found to provide high accuracy for signal propagation over water where there are no objects in close proximity to the propagation path. However, with vegetation in close proximity, accurate signal variation predication must consider contributions from scattered and diffused components, taking into account frequency selective fading characteristics to represent the temporal and spatial signal variations.
      1  7