Siti Marhainis Othman
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Siti Marhainis Othman
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Siti Marhainis, Othman
Alternative Name
Marhainis, Siti
Othman, S. M.
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Scopus Author ID
55210362500
Researcher ID
ABF-6513-2020

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Identification of ARX Model for Thermoelectric Cooling on Glass Windows

2022-01-01 , Mohd Saifizi Saidon , Nasrul Amri Mohd Amin , ‘Aqilah Che Sulaiman , Mohd Rizal Manan , Siti Marhainis Othman , Wan Azani Wan Mustafa , Arith F.

Thermoelectric cooling (TEC) is a solid-state heat pump that uses the Peltier effect to dissipate the heat generated by the electronic packaging system. TECs are widely used in aerospace, military, scientific work and industry due to small size, lack of moving parts, and ease of integration. In this study, a cooling system integrated with TEC is developed in a testing area (lecturer’s office) with the aim to reduce the temperature of the hot glass window area due to solar radiation that passes through it. This cooling system used direct TEC, for keeping the cooling temperature on the window to about 26 °C which is equivalent to an air conditioning setting temperature of 26 °C set during the experiment. This work includes experimental and modelling studies conducted on cooling systems integrated with TEC. The main target of this study is to develop a dynamic model of a cooling system integrated with TEC. The black box modelling approach in producing a mathematical model was selected based on the ARX model that corresponds to the actual dynamic state of the cooling system. The best model was finalized based on the best match on curve patterns when comparing the real and estimated models using the system identification tools in MATLAB, and also had the least error. The accuracy of the models was compared and analysed. The results showed that the 4th order of the ARX model produced a higher best fitting and standard deviation values of 78.14% and 0.030769. This system accuracy is almost within the acceptable range for most error calculations in the validation method. In addition, the ARX model is found incapable of achieving the highest fitting due to the losses from the dynamic environment and losses from the TEC itself. Still, the use of this black box model used in this study is a significant variation where system parameters can be identified even offline.

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Robot Face and Its Integration to the Mobile Robot for Wireless Signal Collection in the Fingerprinting-Based Indoor Positioning System

2021-12-01 , Sarhan M.A.H. , Abdul Halim Ismail , Mohd Nasir Ayob , Hashim M.S.M. , Muhamad Safwan Muhamad Azmi , Hassrizal Hassan Basri , Siti Marhainis Othman , Muhammad Juhairi Aziz Safar

The wireless data collection for instance the Received Signal Strength (RSS) of the Wireless Fidelity (Wi-Fi) remained unfavourable in the Indoor Positioning System utilizing the signal fingerprinting approach. This is because the enormous sampling time and routines works making it tedious human labour. To alleviate this issue, we propose to use a robot for wireless data collection. The robot, named 'ICSiBOT' is a service robot with multiple purpose such as assisting human in daily lives, guest or hospitality robot and man others. This paper mainly describes the ICSiBOT robot face with speech recognition technology and the integration of the robot face to the motion controller. The experimental was conducted to see the correlation between the synthesized instructions from the speech in terms of distance need to be travelled i.e., the location for wireless signal collection and translate them into actual distance travelled. The results showed that the robot is able to travel to the specific distance as instructed to the robot face.

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Model Reference Adaptive Controller Design for Electrohydraulic Actuator System with varying disturbance

2022-01-01 , Siti Marhainis Othman , Wong Kar Yi , Rustam R.A. , Rahmat M.F. , Mohd Shuhanaz Zanar Azalan , Muhamad Safwan Muhamad Azmi , Hashim M.S.M. , Siti Nurul Aqmariah Mohd Kanafiah

The objective of this study is to design and analyze the performance of the designed controllers on the presence of varying mismatched disturbances. This research provides a clear the selected approaches for the controllers’ design implementation of the electro-hydraulic actuator (EHA) system, an adaptive controller, the Model Reference Adaptive controller (MRAC). Subsequently, this research is considered another controller, the Proportional Integral Derivative (PID) for comparing the best control performance for the electro-hydraulic actuator system with varying mismatched disturbance. PID controller has been tuned by using two different tuning techniques. The Trial-and-error and Ziegler-Nichols tuning method have been proposed for attaining the desired control system response in this research. Simulation results show that the MRAC provides the best response performance among the designed methods for every specific disturbance setting at 0 N, 5000 N and 10,000 N. The MRAC method dominantly achieves the faster response in rise time for every disturbance respectively.

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Hand-held shelf life decay detector for non-destructive fruits quality assessment

2024 , Nurul Syahirah Khalid , Nordiana Shariffudiin , Shazmin Aniza Abdul Shukor , Humairah Mansor , Masturah Tunnur Mohamad Talib , Sukhairi Sudin , Ismail I. Ibrahim , Mohd Zamri Hasan , Siti Marhainis Othman , N.D.N Dalila , M.Thaqif B.N Ashimi

Perishable food such as fruits have a limited shelf life and can quickly degrade if not properly stored. One method for detecting decay in these foods is the use of ethylene gas. Ethylene is a naturally occurring hormone that is released by fruits as they ripen. By measuring the levels of ethylene in the storage area, it is possible to detect when fruits and vegetables are starting to degrade. This information can then be used to act, such as removing spoiled produce and adjusting storage conditions, to extend the shelf life of the remaining products. By utilizing ethylene gas for early detection of decay, it is possible to improve food safety and reduce food waste. The project aims to utilized ethylene gas from perishable food such as fruits before decay. This project proposed portable or hand-held detection ethylene gas by including temperature and humidity. The sensor will be measuring the level of ethylene gas, temperature and humidity. Next, machine learning method; K-Nearest Neighbour(KNN) were used to evaluate the accuracy of the proposed system. This project, a hand-held decay detector for perishable food products is believed can help to prevent food waste by detecting early signs of spoilage in fruits.

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Temperature control using fuzzy controller for variable speed vapor compression refrigerator system

2022-01-01 , Siti Qurrata Ain , Mohd Saifizi Saidon , Siti Marhainis Othman , Aziz A.A. , Wan Azani Wan Mustafa , Wan Khairunizam Wan Ahmad

Keeping the cold chain vaccine is crucial to a stable immunisation programme; however, faulty processes may occur more frequently than are often thought in developing nations. This paper discusses the quick and accurate control process for designing fuzzy controllers for variable speed vapor compression refrigerator system. The suggested controller is based on the fuzzy logic intended to improve performance while keeping the cooler’s constant internal temperature and increasing the refrigerator efficiency. Despite the external changes such as the outside temperature change or the volume change in the refrigerator vaccine, the fuzzy logic controller is utilised to maintain the interior temperature. However, a variable speed compressor (VSC) must be used to control the thermophysical characteristics, which dramatically alter the temperature with a small pressure change. In this case, fuzzy rules of the sort developed by Mamdani are used to build up the system. The programming platforms utilised to implement the model include MATLAB, SIMULINK, and Fuzzy Logic Toolbox (FLT). The efficiency of fuzzy logic controller design membership will be compared to ensure that the refrigerator temperature is more accurate and until it achieves the best performance, maintains a temperature of 5°C, and adapts to its surroundings. From the research done, the membership 2 with load shows the near accurate temperature of 5°C with steady-state error ±1.97°C.

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Characteristic Study of Supercapacitor's Discharging Process Base on BLDC Motor

2023-01-01 , Mohd Azri Abd Aziz , Mohd Saifizi Saidon , Muhammad Izuan Fahmi Romli , Siti Marhainis Othman , Wan Azani Wan Mustafa , Al-Dolaimy F. , Alkhayyat A.

Energy storage has become a key issue for achieving goals connected with increasing the efficiency of both producers and users. In particular, supercapacitors currently seem to be interesting devices for many applications because they can supply high power for a significant amount of time and can be recharged more quickly than electrochemical batteries. Supercapacitors, as similar to conventional capacitors build on two plates separated by a dielectric and an electrolyte, can store more energy than conventional capacitors because they can produce two distinct layers of separated charges between plates, which are typically made of porous, carbon-based materials. The supercapacitors module serves as the power supply for the discharging process as called Energy Storages (ES). The main purpose of this research is to investigate the behaviour and properties of discharged supercapacitors. The design is created using Simulink and includes a circuit schematic and scope label. Using Brushless Direct Current Motor (BLDCM) as a load, study proposed steady state condition and dynamic state condition of BLDCM operation are investigated. With comparison to battery, preliminary finding state that value of SoC and voltage of battery higher but value of current less than supercapacitor in a certain amount of time.

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Intelligent Classification Procedure for Plasmodium Knowlesi Malaria Species

2022-01-01 , Siti Nurul Aqmariah Mohd Kanafiah , Mohd Yusoff Mashor , Mohamed Z. , Jusman Y. , Hasimah Ali , Nordiana Shariffudin , Siti Marhainis Othman

Plasmodium knowlesi (PK) is the fifth most prevalent malarial parasite species that causes serious health problems. Generally, PK present in a thin blood smear is observed using a microscope to differentiate between trophozoites (PKT), schizonts (PKS), gametocytes (PKG), and white blood cells (WBCs). This process is time-consuming and strenuous for the human eye. This study developed an intelligent classification procedure for PK using image processing and classification methods. The processes involved starting from image acquisition, and contrast enhancement based on Combination Local and Global Statistical Data (CLGSD), and local contrast stretching (LCS). Subsequently, a segmentation procedure was developed to segment the malaria images into two regions, namely malarial parasites and background regions. The proposed 16 feature sets were extracted, which consisted of the size of the object, size ratio of the object per infected RBC, and seven moments for each object shape based on size and perimeter. Finally, to validate the procedure performance, the proposed procedure was tested using 800 malarial parasites and WBC images. The results showed that the proposed procedure can classify three stages of PK, namely PKT, PKS, and PKG, as well as WBCs with an accuracy of 99.56% for training and 98.84% for validation, using a multi-layer perceptron (MLP) trained using the Levernberg-Marquardt (LM) algorithm.

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Efficiency analysis of a passive daylighting system based on Northern Malaysia’s climate

2025-04 , Mohd Sani Mohamad Hashim , Muhammad Amin Zulkifli Din , Abdul Halim Ismail , Mohd Hafif Basha Mohamad Jamel Basha , Nasrul Amri Mohd Amin , Ng Yi Fei , Muhamad Safwan Muhamad Azmi , Siti Marhainis Othman , Nur Saifullah Kamarrudin

Daylighting design strategy is important in order to have adequate lighting source in a room and necessary to decrease energy consumption for artificial lighting. Passive daylighting system utilizes daylight by collecting, reflecting and diffusing the natural light throughout a given area. The purpose for this study is to monitor, compare and analyse an optimum light pipe system design that can scatter daylight into a room based on three case studies. Lighting analysis was conducted using Autodesk 3ds Max Design software throughout the project based on the actual geographical parameters of Universiti Malaysia Perlis, Malaysia and also using the real sun azimuth on working hours. The results were compared according to the respective designs in order to observe the maximum internal illuminance and the average internal illuminance. The results show that the straight geometry with low aspect ratio produces the highest interior light intensity among other light pipe systems and the average internal illuminance values in the room was able to reach the minimum requirement of a small room which is 200 – 500 lux.

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Automatic Recognition System of Iron Deficiency Anaemia in Human RBC using Machine Learning Techniques

2023-01-01 , Siti Nurul Aqmariah Mohd Kanafiah , Jusman Y. , Shazmin Aniza Abdul Shukor , Ibrahim W.N.A.B.W. , Nordin S.A. , Tohit E.R.B.M. , Ali H.B. , Nordiana Shariffudin , Siti Marhainis Othman

Iron Deficiency Anaemia (IDA) is the most common blood disorder. According to WHO, 30% of women aged 15-49 years, 37% of pregnant women, as well as 40% of children aged 6-59 months are anaemic globally. Anaemia can cause premature birth and affect mental, physical, and cognitive development, which in turn will lead to birth weight problems and stunted birth. The process of detecting IDA is usually captured based on a thin blood smear utilizing microscopic observation. Nevertheless, this process can be time-consuming. Moreover, it is challenging to identify the difference between IDA and normal red blood cells (RBCs) because the size is similar based on the observation of the human eye. It will cause difficulty in giving drug treatment to patients. A computeraided diagnosis (CAD) method was created to automatically distinguish between IDA and normal RBCs. The processes started with image acquisition, image processing, and recognition. Additionally, a Graphical User Interface (GUI) is also used to display images. In conclusion, recognition was done using the Multilayer Perceptron (MLP) method. The findings indicate that the proposed automated system is effective at distinguishing between IDA as well as normal RBCs, having an accuracy of 97.58% with regard to training and 98% regarding validation utilizing Levenberg-Marquardt (LM) trained MLP.

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Design and implementation of closed-loop PI control strategies in real-time for Linear ARMAX Models of Vapour Compression Refrigeration System using R600a Refrigerant

2022-01-01 , Rajaie M.N. , Mohd Saifizi Saidon , Siti Marhainis Othman , Wan Azani Wan Mustafa

The objective of the research undertaken in this paper is to design a control strategy using a Linear Auto-Regressive Moving-Average Exogenous (ARMAX), which is a mathematical modelling method in real time, which to be implemented into the closed-loop Proportional-Integral controller. The ARMAX model is developed using SIMULINK tool from the MATLAB R2020a software. The Vapour Compression Refrigeration System consists of an evaporator, an expansion valve, a condenser and a compressor which was modified to a variable speed compressor. This modification is required due to the usage of R600a refrigerant that has thermophysical properties that can be described as with a slight change in its pressure will cause a considerable change in its temperature [1]. R600a refrigerant was chosen for this paper, despite the difficulty is due to it is more environmental-friendlier refrigerant compared to other types of refrigerant [2]. Two types of ARMAX model were designed, the first type of ARMAX model will have a polynomial order of na= 2, nb= 2, nc= 1 while the second type of ARMAX model will have a polynomial order of na= 2, nb= 2, nc= 2. Both types of controller were tested and compared the performance in terms of settling time, steady-state error, overshoot and peak-time. From the test conducted, it was found that the controller with the ARMAX model will have a polynomial order of na= 2, nb= 2, nc= 1 has a better overall performance.

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