Universiti Teknikal Malaysia Melaka: UTeM Open Journal System
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Comparative Study on the Performances of PV System with Various Combinations of Converter Topologies and PWM Types
Get PDFIncreasing demand for electricity generated from renewable energy sources forced power utility provider to develop more and larger power plant. In Malaysia, among renewable energy sources, photovoltaic (PV) is the most reliable. Hence, large-scale PV power plants have been developed and many more to be developed in the future. In case of large GridConnected PV (GCPV) power plant, the converter which is nonlinear load will generate Total Harmonic Distortion (THD) into the electrical power system. Harmonic generated by the PV system may downgrade the quality of power grid and affect the reliability and safety. In addition, other main concerns in GCPV system are switching losses of the switching devices in the converter and the cost of the converter. These performances can be improved by the right choice of Pulse Width Modulation (PWM) type and converter topology. This paper will discuss which PWM type and converter topology should be chosen to produce the optimal performance based on THD, switching losses and cost. In general, the best combination is a two-level converter with continuous PWM (CPWM) where the cost is almost half compared to the three-level converter and having optimal value in the combined performance of THD and switching losses
Wearable Kinesthetic System in Post-stroke Rehabilitation: A Review of Sensor in Body Motions Detection
Get PDFThis paper presents a system with various kinematics parameters considered to capture and classify body gestures for user’s recovery. The concepts involved are briefly explained in this paper. Basically, two devices concepts are explained, which are the Upper Limb Kinesthetic Garment (ULKG) and OPAL technologies. The method of literature search used is discussed in methodology, while detailed information from reviews on particular devices is analysed. Then, the performance and feedback from users are compiled to indicate usability on both devices under the results section. Both ULKG that used conductive elastomer (CE) and OPAL sensor are compared to figure out which sensor is more appropriate for users
Microcontroller-Based Power Monitoring and Switching Device for Appliances over a ZigBee Network
Get PDFMicrocontroller-Based Power Monitoring and Switching Device (PMAS) for Appliances over a Zigbee Network aims to develop a system that can provide aid to its user in consuming power more efficiently. This study aims to create a system for monitoring electrical consumption of home appliances through an Android application. It will also be focusing on the recording of electrical data so that its user may be able to track how much power they are consuming over a certain period of time. The microcontroller in the power monitoring and switching (PMAS) adapter will read and measure electrical data, such as voltage, current, and power. This data will then be transmitted to a hub that will be utilizing a ZigBee network, connected in a star topology. This gateway sends and receives data to and from the web server database, which the Android App accesses to display the information to the user through text and graphs. The app also has switches that can turn the adapter on or off. This study provides users with an easy to install and non-intrusive system to monitor and control the power consumption of home appliances using an Android app
Users’ Acceptance Study of OAuth Manager Module for Social Login in Mobile Environment
Get PDFSocial login is a way that allows social network users to use their credential to log in to other applications. Currently, many developers make use of Open Authorization (OAuth) protocol to implement social login (SL). The design of OAuth protocol works well on workstations and desktops as they uniformly use web browsers to access web applications. However, it is exposed to security issues when it is moved to the mobile environment. Although native mobile applications are installed on the mobile devices, this protocol will call system browsers to complete the task; hence, exposing users to token redirection attacks. In overcoming the issue, this study attempts to evaluate a method called OAuth Manager Module (OMM) that aims to improve the security of this protocol in a mobile environment. It provides client isolation to prevent malicious actions during the social login process. A controlled experiment was conducted to evaluate user acceptance towards OMM. A within-subject design was conducted on thirty participants who participated in this study on a voluntary basis. The results show that users perceived OMM useful and easy-to-use compared to social login with system browser. However, in overall, users are still worried about the security of using social logins on mobile devices. This study can further serve as a foundation for various research on the security aspect of social login
The Applications of Shape-Changing Rigid Body Mechanisms in Arts and Engineering
Get PDFDesign of shape-changing or shape-morphing machines is an area of growing importance. Shape-change can potentially be applied soon to vary the cross section of a wing, create wind or liquid flow control by morphing shapes to locally influence downstream fluid behavior, or vary the size of a car seat to meet a wider array of human anthropometric needs. Rigid body shape-change mechanisms offer many advantages including the high capacity to endure substantial loads while achieving large displacements. Their design techniques are also well-established. The goal of this research project is to develop the synthesis theory to address planar rigid-body shape-change where significant differences in arc length define the problem. A MATLAB-based software was developed to facilitate visual assessment of the process and results. Lastly, this paper illustrates several mechanization examples that apply the segmentation process, and the fundamental mechanism synthesis to guide the motion of the chain of rigid bodies to progress to the subsequent positions
High Speed Low Power CMOS Comparator using Forward Body Bias Technique in 0.13 µm Technology
Get PDFThis paper presents the design of high speed and low power CMOS comparator using a forward body bias technique in 0.13-µm technology. Three types of CMOS comparators’ topologies have been designed in order to compare the performances of speed and power with the conventional comparator. Based on the analysis, the double-tail dynamic comparator is chosen since it shows better performance for high speed and low power. Therefore, a modified high-speed, low power double-tail dynamic comparator is proposed by using a forward body bias technique in order to reduce the supply voltage. The proposed dynamic comparator is implemented in Silterra 0.13-μm CMOS technology with the supply voltage of 1.2 V and sampling frequency of 500 MHz using Cadence EDA tool. The simulation results show that the total power of 152.67 µw with the delay of 72.5 ps is obtained. It can be seen that the proposed dynamic comparator has significantly reduced both the power and delay time compared to the previous design
Design and Analysis of Frequency Selective Surface (FSS) Using Complementary Techniques on Glass
Get PDFThis paper presents the design of square Frequency Selective Surface (FSS) based on a complementary technique for energy saving glass (ESG) application. In this paper, there are four designs of FSS that have been presented which are a square patch (Design A), square patch rectangular slot (Design B), complementary square patch with a rectangular slot (Design C) and complementary square patch with rectangular slot and square loop (Design D). All design used glass as a substrate and aluminum as the conductive patches. The unit cells of each design are simulated using CST Microwave Studio software. The simulation process is based on the characteristics of reflection coefficient (S11) and transmission coefficient (S21) of the FSS. The simulation result shows that Design B exhibit pass band at 5.2 GHz. While, Design D produce dual pass band at 1.7 GHz and 5.2 GHz. Therefore, this design can be used to improve the transmission of the wireless communication signal
A comprehensive study on the efficiency of three different types of the variable metric method in determining the unknown Rocket inner heat flux
Get PDFIn this paper, the unknown heat flux is estimated with Davidon-Fletcher-Powell (DFP), Broydon–Fletcher–Goldfarb–Shanno (BFGS) and Symmetric Rank-one (SR1) version of variable metric method (VMM). The numerical techniques used in this study solved the inverse problems with various boundary and environmental conditions very efficiently. The results shows the sensitivity of measurement errors and different parameter including changes of slope and angle which can be functions of an unknown parameter. Further, the speed of convergence is assessed and the convergence behavior is found. The accuracy of results show that this study is a powerful reference for comparing results obtained based on the three proposed techniques. The solution procedure introduced a general cheap and fast method which can be used for the inverse heat conduction problem in rocket nuzzle and same heat conduction, radiation and convection problems
BOARD’S EQUITY OWNERSHIP AND THE PERFORMANCE OF BAILED-OUT BANKS IN NIGERIA
Get PDFThis paper extends an earlier proposed framework and thus empiricallyexamining the effect of board equity ownership on the performance of banksin an era of post banking crisis that called for a bailout reform in Nigeria.This board attribute is selected based on the peculiar problem of the bankingsector, and based on the board functions that captures monitoring (agencytheory based). Based on a survey data, the result of our analysis revealed asignificant relationship between board of directors’ equity ownership andbanks performance. We therefore, suggest more regulation and enforcementof this as it motivates and compels boards to be more vigorous at monitoringCEOs/top managements
Industrial Solid Waste Management for Better Green Supply Chain: Barriers and Motivation
Get PDFMoving towards green supplychain activity requires an effective wastemanagement that is applicable and efficientfor all industries. The aim of this paper is tofind out the barriers and the motivation of themanufacturing companies to implement solidwaste management. Barriers are found includeslack of technique and technologies, lack of policyenforcement and responsibility and insufficientof awareness and knowledge. Motivation that ledthe manufacturing companies to implement solidwaste management through encouragement ofgovernment, encouragement of non-governmentorganization and socio-psychological incentive. Anumber of databases in fields such as sociology,social sciences, psychology, and economics wereused to acquire literatures on the topic. Thefindings of the paper include the types of factorsthat motivate and demotivate the manufacturingcompanies to implement industrial solid wastemanagement effectively. The paper ends withrecommendations on future research on howthese factors will help manufacturing companiesto implement industrial solid waste managementeffectively and future research for betterenvironment