Pusat Pengajian Kejuruteraaan Elektrik dan Elektronik - Tesis
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- Publication3d facial verification using stereo vision(2010-04-01)Tai, Shu WornFace recognition has been a focus in research for the last couple of decades because of its wide potential applications and its importance to meet the security needs of today’s world. This project proposes a face recognition system that uses passive stereo vision to capture three-dimensional (3D) facial information and 3D matching using a simple Sum of Squared Difference (SSD) algorithm. So far, the reported 3D face recognition techniques assume the use of active 3D measurement for 3D facial capture. However, active methods employ structured illumination (structure projection, phase shift, gray-code demodulation, etc.) or laser scanning, which is not desirable in many human recognition applications. An advantage of passive method is that it costs lower than active method. This system uses a stereo camera to locate, track, and recognize a person’s face. This algorithm improves state-of-the-art monocular 2D object recognition techniques by additionally considering the facial 3D surface, which is relatively stable under different lighting conditions. First, faces are detected and their surfaces are reconstructed from the stereo images. Afterwards, a 3D face is composed by joining 2D image data and appropriate depth data. The 3D face is then decomposed into its principal components. The principal components are used to recognize a 3D face by comparing characteristics of the current face to those of known individuals in a database. The result is an efficient and accurate face recognition algorithm.
- Publication3d networked virtual representation(2009-04-01)Tan, Hong PingThree dimensional (3D) virtualization has been a popular method to observe and present data and simulation results. Although many robotic applications have applied 3D virtualization technology for simulation, there is not much applications which incorporate 3D technology into computer networking to develop a networked virtual environment (net-VE) with teleoperation ability. This project aimed to realise such system, where multiple users able to control and view the virtual mobile robots, in addition, able to teleoperate a real mobile robot through the virtual environment. This project presented the system, 3DVR©, which has all the features of a net-VE system with teleoperation function. 3DVR© is being developed using Python scripting language, and Panda3D® engine for 3D virtualization. The implementation of 3DVR© shows 3D virtualization of 3D models and environment in a graphical user interface (GUI) with functions in aiding the users to view and navigate around the virtual environment. There are four operation modes in 3DVR©; which are local virtual robot simulation, local real robot teleoperation, mobile robot teleoperation through local area network (LAN), and mobile robot teleoperation through internet. The four operation modes are successfully demonstrated with virtual mobile robot models and the results obtained are promising.
- PublicationA benchmark low voltage of microgrid network(2010-04-01)Zulkifli, Nurul AsiahA study about microgrid network has been conducted to explore new and environmental friendly renewable energy. A few relevant papers concerning the microgrid network as higher energy efficiency and by facilitating the integration of renewable sources that is potential in the future market have been collected and studied. New renewable and efficient energy resources offers an alternative solution which integrating a network that is microgrid network. Microgrid can be connected to the main power network or be operated autonomously, similar to power systems of physical islands. Microgrid network is usually connected to an electrical distribution network in an autonomous way and employs various distributed generation technologies such as micro-turbines, fuel-cell, photovoltaic arrays, wind turbines and others system together with energy storage devices such as battery, condenser and flywheel. In addition, the benchmark low voltage provides the guidelines in the design of low voltage microgrid network. Moreover, standardizing case study grids to provide benchmark networks suitable for microgrid design would further enhances their merit and utility. Microgrid may potentially offer various advantages to end-customers, utilities and society, such as; improved energy efficiency, minimized overall energy consumption, improved services quality and reliability and also cost efficiency electricity infrastructure replacement.
- PublicationA study and loss modeling of rf to dc converter(2010-04-01)Mohd Naim, Nor ‘AdilahSensors without battery are one of the essential requirements in passive sensor. A rectifier circuit is used to convert the coupled AC electro-magnetic waveforms to a DC voltage and serve as a power supply for the rest parts of the sensor circuits. The RF transmitter transmits sufficient energy to power up the sensor at large distances. However, the rectifier output is limited on the amount of power that can be transmitted by transmitter and the path loss associated with electromagnetic propagation. Apparently, there is a little power that reaches the sensor. Therefore, the power harvesting circuit design must maximize the operating distance in order to activate the sensor by converting the limited incoming RF power to DC power with a sufficient voltage. The initial design of the rectifier was based on a full-wave regulator voltage doubler and later modified to the cascade doubler circuit. Some simulations are done by using Multisim simulation tools during the design of the rectifier. The high frequency rectifier has been designed using Eagle layout tools and the layout has been fabricated. There are another designs needed in this project which is feeding board of antenna. Computer Simulation Technology (CST) software was used to draw the schematic of feeding board in order to get the layout drawing for the design. Some calculations are performed during MAX757 design to determine the value of resistor that should be used. When the circuit board has been fabricated measurement part started. Measurement part includes of transmitter and receiver antenna, rectifier and voltage regulator. From measurement, both antennas working perfectly in the range of UHF and the voltage regulator is working in stand alone with the output is 3.489 V. The minimum operating for Ceramic antenna is 725 MHz while LPRS antenna is 624 MHz. For the rectifier part, it was working but the desired output cannot be obtained due to some loss efficiency such as impedance mismatch, path loss, threshold voltage and sensitivity of Schottky diode and losses in the circuit. It is obtained when comparing the input power (25 dBm = 316 mW) with the output power of rectifier (1.2V x 0.012μA = 0.144 μW). When the rectifier connected with voltage regulator, the output is lower than 1.8 V due to the loading effect problem. After taking note the causes of loading effect, a test is done to verify the problem. The test result shows the loading effect occur with the combination of rectifier and voltage regulator.
- PublicationAdopting j2me for the development of mobile phone application(2010-04-01)Paul, Yung Han FuiMobile phone has been a widespread application throughout all stage and standard of life. Java is ideally suited to become the standard application development language for mobile phone because it provides us with lots of benefits. Hereto some of the most important ones are Cross Platform Compatibility, Object Oriented Programming, Huge Java Developer Community, Security, and the its Dynamic nature. In this project, Java 2 Micro Edition (J2ME) has been used primarily to develop a context-aware application that feeds the user information about the current weather with SQL server running in the background to generate XML. This application will give the user a real-time update on the current weather in certain location which can be accessed from the mobile phone. It is a very useful and significant application especially for those taking weather factors as a major concern in realizing their activity or reaching particular destination.
- PublicationAnalysis of harmonic current produced by ac-dc converters with various firing angles(2009-04-01)Nik Hassan, Nik Mohd FaridThe main propose of this project is to analyze harmonic input current produced by AC to DC converter by varying firing angle.Generally,the analysis of input current can be defined as changes to Total Harmonic Distorted. This overall project analyzes 2 variables to relate firing angle with thyristor by differences of the total harmonic distorted.The AC to DC converter that is used is single phase AC to DC converter and three phases AC to DC converter.The AC to DC one phase converter used 4 thyristor while 3 phase AC to DC converter used 6 thyristor as as switch.The resistance being assumed in this analysis is pure resistance.The values of capacitor and inductor resistance are not considered. The purpose of doing so is to neglect the value of Power Factor for the AC to DC circuit.In this Project,3 steps is taken to analyze the relationship of firing angle in thyristor to the total harmonic distorted.The first step is to use theories of input waveform current harmonic changes and this value is interpreted by Fourier Series.Based on the results obtained from the three methods,for single phase control rectifier,it can is observed that the firing angle is directly proportional to THD,and the range varying angle obeys the standard introduced by IEEE for THD,which is less than 20% for angles of 0° to 40°.For three phase control rectifier,it is observed that the firing angle increases with respect to THD,and no range firing angles obeys the standard of IEEE.This is because based on the experiment,3 phase controlled rectifier,when the varying angle of thyristor is 0°,the THD value is 26.7%,and exceeded the standard fixed by IEEE.
- PublicationAnalysis of power flow by using pscad and matlab(2010-04-01)Sng, Wei NianIn power engineering, power flow studies, also known as load flow studies, are the backbone of power system analysis and design. The great importance of the power flow studies are the planning, operation, economic scheduling and exchange of power between utilities. The power system of today is a complex interconnected network consists of generation, transmission and sub-transmission, distribution and loads. The load flow problem usually comes with many nonlinear algebraic equations. The power flow computations can also be complicated and challenging due to large number of buses and high complexity of the system. Therefore, computer-aided softwares are applied to give solution to the load flow problems. In this project, the power flow problems are solved by using PSCAD/EMTDC simulation and MATLAB software. The objective of this project is to develop the power flow models using PSCAD schematic layout and solve the load flow problems using both PSCAD simulation and MATLAB software. The results from the PSCAD are compared with the MATLAB results and the percent difference of the results are determined and analysed. The methodology developed in this project involves understanding the theories of power flow analysis, power flow solution using PSCAD simulation and MATLAB software as well as comparison of results obtained. After comparing the outcomes from the three cases, the percent difference of the results between PSCAD and MATLAB is in the range of 0% to 0.13%. Both PSCAD simulation and MATLAB software are capable of handling power flow computations of different power systems with good estimate of results.
- PublicationAnalysis of power system harmonic effect on power distribution transformer(2010-04-01)Hayon, Nor HalimThe increases use of non – linear load has increased the level of harmonics in electrical power system. The increases of harmonics cause the reducing of the transformers life expectancy. The used of rating system called K – Factor is to ensure that the transformer can operate safely when supplying non-sinusoidal load current. The effect of harmonic on distribution transformer is reported in this thesis. The experiment was conducted at three phase transformer with capacity of 500 VA. The effect of harmonics on distribution transformer has been investigated by connecting non – linear load to the output of transformer. The load used in the experiment are resistance and rectifier. In addition, the effect of harmonic to the transformer such as losses, power rating, power factor and temperature rise. The analyzing the derating method also introduced to reduce the harmonic effect on transformer. The derating method is suggested accordance to BS7821 standard. The results show that the temperature increased linearly when total harmonic distortion increases. The power loss also increased linearly when total harmonic distortion increased. The power factor of transformer decreased linearly when total harmonic distortion increased. For %THDi 24.3%, 38.8%, 64.3%, 70.8% and 80.7%, the percentage of derating transformer is 92.59%, 89.91%, 86.82% , 85.51% and 85.40%.
- PublicationAnalysis of rf-to-voltage power detector for outdoor application(2009-04-01)Ng, Gua BinThis is a dissertation regarding the analysis of RF power detector for outdoor application. RF power detector is an apparatus provided for detection of the output power from an RF power amplifier for purposes of controlling the output power. It is important in wireless communication system since each system has a specific power regulation and strength. This leads to the need for selectivity and good control of the output signal’s level. This became a fundamental issue in the design of any communication system. Therefore, AGC circuits become an important system especially for any device or system where wide amplitude variations in the output signal could lead to a lost of information or to an unacceptable performance of the system. Since there are various types of power detector available in the market, logarithmic amplifier was utilized to be implemented in AGC circuit after considering some factors. Before implementing on practical environment, analysis on log amp and AGC circuit is done by using ADS software. After that, the AGC practical circuit is presented and analyzed on breadboard according to the simulation circuit. From the analysis, the performance of AGC practical circuit is better in between 500 kHz and 1 MHz frequency range with a 40dB dynamic range.
- PublicationArtificial neural network for gas-oil flow pattern recognition using capacitance tomography data(2009-04-01)Tan, Kim LengThe technique to recognize the oil and gas flow pattern in a pipe is needed in the oil and gas industry to monitoring the condition of the oil and gas pipe system. Any mistake or malfunction may lead to serious loss and endanger the workers and environments. Generally there are lots of flow pattern such as Empty, Full, Stratified, Bubble, Core and Annular. The Electrical Capacitance Tomography (ECT) technique is used to take the cross sectional data of the pipe. The Artificial Neural Networks (ANNs) is used to recognize the flow patterns. This project uses the Multilayer Perceptron (MLP) as the ANNs model. The MLP is trained, validated, and tested with the ECT data. The ECT data is divided into three groups, training, validation, and testing. The Matlab software is used to build the MLP architecture. The learning algorithms used for this project is the Levenberg-Marquardt algorithms and the Quasi-Newton algorithms. Result show that trained MLP is able to give a percentage of accuracy of 99.102% in oil and gas flow pattern recognition. This shows that the MLP is suitable to be used in the oil and gas flow pattern recognition.
- PublicationAttenuation in vegetation(2010-04-01)Hashim, Yus’aimanThis is the final report of the project to investigate 2.4GHZ frequency transmitted between two points with object and without obstacle (line of sight). The report provides summering previous model of signal propagation through vegetation. To study losses of signal strength (energy or power) when transmit between two points with different situation or vegetation density. Comparison result between measurement with analytical mathematical will be discuss in this paper. To discuss vegetation losses when signal traveling in different density and different parameters with the same temperature. The core of the challenge in this project to understand the cause of error between models given compare with measurement. Conclusion, solve the problems and find another method or alternative way to reduce losses at the same time improve performance
- PublicationAutomation of voltage using analog voltage margining card(2009-04-01)Loh, Han YangIn this project, voltage automation scripts for Analog Voltage Margining Card (AVMC) are being developed. The AVMC card is a card used to support analog validation of a target test system. It supports margining of target voltage supplies through voltage and simulated current controls. AVMC is used to replace ADM1066 chip for the voltage margining due to its accuracy and flexibility. Voltage automation scripts are written using bash language because it is suited for automation tasks. For the scripts to work, an operating system called System Validation Operating System (SVOS) such that user can margin the voltage by entering a single command. The voltage margining scripts generated is being tested on two types of Intel board which are Pinetrail and Tigerhill. Seven Pinetrail and five Tigerhill boards are used for testing the voltage margining scripts. When running a script on a board, the output voltage on the board is being measured using a digital multimeter. The measurement is then compared to the actual or desired value of the user. Voltage margining had been carried out to each available board and it shows that the scripts work. Hence, the voltage margining scripts for AVMC had been successfully developed and is currently used for running test purposes in Intel.
- PublicationAutonomous navigation using stereo vision(2010-04-01)Lok, Sook WanObstacle detection is the main issue for safe navigation and it can be achieved by applying stereo vision. In stereo vision, two cameras placed horizontally from one another on the mobile robot platform. These cameras are used to obtain differing views on a scene, in a manner similar to human binocular vision. The first step is camera calibration by using Matlab Camera Calibration Toolbox. The camera calibration process estimates camera’s intrinsic parameters and calculates extrinsic parameters of the camera. The result of the calibration process is used for image rectification to transform the corresponding epipolar lines in all images so that they become collinear with each other. Rectification is able to eliminate errors caused by lens distortion and camera displacement. This greatly simplified the implementation of the stereo matching algorithms. Stereo matching algorithm is used to find the corresponding points in stereo image and produce disparity map, which is inversely proportional to object distance. In this project, using a predefined window size, two different stereo matching algorithms, Sum of Absolute Differences (SAD) and Sum of Squared Differences (SSD) are implemented and their performance is compared. A pair of points is considered to match if the SAD or SSD value is small enough and minimum among all values computed within the possible disparity range. The disparity map generated is analyzed and processed to find the distance between the objects. The performance of SAD and SSD are quite similar. However, the processing time of SSD is longer than that of SAD because it requires an extra step in the squared calculation. As a conclusion, by using stereo matching algorithms to extract 3D depth information, the mobile robot is able to distinguish obstacles from the free space ahead. It is able to move forward by avoiding obstacles.
- PublicationBuffer design for the inductively-degenerated lna for w-cdma application(2009-04-01)Wong, Pi WeIn this thesis, a 0.18μm CMOS buffer design for a PCSNIM W-CDMA LNA was proposed and analyzed in detail. This buffer is a simple class-AB voltage follower which uses a capacitor as feedback and a cascode current mirror as the biasing circuitry. Together with the PCSNIM LNA, this buffer design was simulated using Cadence SpectreRF. This design was implemented using Silterra 0.18μm technology and draws 0.99mA current from the voltage supply of 1.8V. This buffer operates with the PCSNIM LNA in the frequency range of 2110MHz to 2170MHz. At frequency 2.14GHz, the S21 is 17.57dB, S12 is - 67.19dB while S11 and S22 are -16.41dB and -24.45dB respectively. The NF is 1.82dB and NFmin is 1.65dB. The P1dB is -25.11dBm and IIP3 is -14.56dBm. Comparing to common drain buffer, this buffer has 16.65% lower gain but 16.69% higher linearity. Besides of that, it consumes 37.34% lower current.
- PublicationBuilding a clock for analog to digital converter timing test(2010-04-01)Heng, Yeh EnThis thesis presents the building of a low-cost, high precision clock for the ADC timing test. There are sixteen clock stimuli required to drive the ADC chip. The 40-pin device-under-test (DUT) ADC is having a resolution as high as 12-bit. The frequency of the designed clock is 2 MHz and the voltage level is 3.3V. The proposed approach utilizes the use of simple digital logic gates to perform all the sixteen clock generation. In short, the circuit is divided into three parts; constant frequency ring oscillator, duty cycle adjustment circuit and voltage regulation circuit. Extra care is emphasized in selecting the most appropriate logic gates for circuit as different family and manufacturer of the gates leads to different results. In the proposed methodology, the model is built on a printed circuit board for a more stable performance. The test methodology was verified in simulation using MULTISIM as well as in hardware. Results show that the proposed methods in generating clocks are easy and accurate. The concept involved in the whole circuit is not complicated and easy to be comprehended. Besides, a 6-bit digital counter is constructed as the supplementary circuitry to test the digital-to-analog converter (DAC). The DAC is meant to translate back the digital output from the ADC to the analog output. Comparison between the DAC analog output and the original analog input is essential to verify the performance of the ADC. As a conclusion, the proposed clock design is the best options compared to others.
- PublicationCircuit analysis simulation for lightning impulse system(2010-03-01)Sapri, Mohd NazlanThe world’s hunger for energy is a growing matter of concern. The people need to find a sustainable amount of energy to meet the world’s future needs and demands. The amount of energy generated from renewable energy sources need to be increased. Many types of renewable energy sources have been used in many countries today. However, there are still no country using lightning as an alternative energy source. Lightning is a very impressive phenomenon that occurs naturally and contained enormous amount of energy in a single stroke. This paper demonstrates the simulation of lightning impulse system using PSPICE software. The main objective is to determine the ability of lightning as energy source generated from renewable sources. The overall lightning impulse system consists of arrestor, transformer and a battery. Since lightning is not applicable in PSPICE, it is designed using equivalent circuit referring to IEC Standard 60060-1. The high voltage from lightning is then stepped down using transformer with a set of impedance to suppress high magnitude of current flow to the system. The ability of lightning as power source is determined through the study of the magnitude of changes variant appears on the battery.
- PublicationClassification of sonar signals using artificial neural network voting scheme(2010-04-01)Hamzah, Nor ShaadahSONAR is a technique that uses sound propagation to navigate, communicate with or detect other objects. In this project, sonar data set are obtained from cylinder at aspect angles spanning 90 degree and from the rock at aspect angles spanning 180 degree. Each pattern is a set of 60 numbers in the range 0.0 to 1.0. Each number represents the energy within a particular frequency band, integrated over a certain period of time. An intelligent system from Artificial Neural Network (ANN) has been applied to the classification of SONAR returns from undersea targets, which are bounced off a metal cylinder and those bounced off a roughly cylindrical rock. Multilayer Perceptron (MLP) ANNs are used to identify and classify each sonar signal. The Bayesian Regularization back-propagation learning algorithm was used to train the network. MLPs that give small average error has been chosen to form an MLP ensemble, and to integrate with a voting system. In this project, MLPs with one and two output classes has been implemented. The performance of both types of MLP output classes are compared.This ensemble system are tested using the verification data set and its performance is compared with single MLPs without the voting scheme. The result show that MLP with one output class can classify sonar signals better than MLPs with two output classes. While, MLP ensemble gives better sonar signal classification than single MLPs. The results demonstrate the feasibility of applying the MLP ensemble to increase the classification performance of classifying the sonar signals.
- PublicationControl strategy of permanent magnet brushlessdc motor using matlab / Simulink(2009-04-01)Manan, NoradzimThe Permanent Magnet Brushless DC motor (PMBLDC) has a permanentmagnet rotor, and the stator windings are wound such that the back electromotive force (BEMF) is trapezoidal. Therefore it requires rectangular shaped stator phase currents to produce constant torque. The trapezoidal back EMF implies that the mutual inductance between the stator and rotor is nonsinusoidal. The objective of this project is to develop a simulation of PMBLDC using Matlab / Simulink software. The result of this simulation is to show theperformance of the PMBLDC by referring its stator current, speed, torque and back electromotive force (BEMF). This result will be compare with the ideal waveform obtained from theory. In this simulation model, the PMBLDC is controlled by hysteresis current controller and PI controller for motor speed.
- PublicationDesign a 24 v dc-to-230 v ac 100w single-phase inverter for photovoltaic application(2009-04-01)Tiang, Tow LeongIn this project, a 100W single phase full bridge inverter will be designed and constructed to convert 24VDC to 230VAC for photovoltaic application. The application used in this project is to control the speed of the single phase induction motor. The speed of the induction motor is changing when the frequency of the single phase inverter is changed. The inverter has been divided into two main parts. That is switching circuit and single phase full bridge inverter. The switching circuit is implemented by using PIC microcontroller, optocoupler and MOSFET driver. There are two types of switching technique i.e. SPWM and single PWM switching techniques. The switching circuit will trigger the power MOSFETs by sending the signal to the gate. The frequency of the inverter will be change if the switches are pressed and send the signal to the microcontroller. The single phase full bridge inverter is built by using four power MOSFETs and the input voltage is 24V. The output voltage of the inverter is stepped up by using a transformer to 230Vrms to run the induction motor. The frequency range is from 30Hz to 70Hz and the speed of the motor is from 754 rpm to 2020 rpm. The efficiency of the inverter is about 84.5%. The THD output voltage of SPWM switching technique is 5.6 % while the THD output voltage of single PWM switching technique is 42.5 % for a resistive load of 300 Ω. PSIM is a simulation tools that used to simulate the project. The hardware is implemented on veroboard and breadboard as well as constructed on the plastic.
- PublicationDesign a large capacity variable voltage of dc power supply(2010-04-01)Ibrahim, Amin ShaharuddinIn this project, a large capacity variable voltage of DC power supply will be designed and constructed. The main function in this project is to convert single phase AC signal to DC signal. The output DC voltage is variable when the firing angle of thyristors is changed. Resistor and highly inductive load are used as load of converter in this project because the load current of converter cannot reach zero and it flow continuously without ripple. The converter has been divided into two main parts. There are switching circuit and single phase full wave converter. The switching circuit is implemented by using a phase control IC, SIEMENS TCA 785. The main reason that this IC being suggested in this project is that it provides two outputs Q1 and Q2 that can be used to trigger a pair of thyristors simultaneously. The switching circuit hardware implement produce firing angle from 0° to 180°. Amplifier circuit is used to amplify 25mA from output of IC TCA 785 to 210mA in order to trigger large thyristor which has minimum gate current of 150mA. The single phase full wave converter is built using four thyristor and input voltage is 240AC. From simulation result, average DC voltage of the single phase full wave converter varied from the 0V to 216.08V. The maximum power can supply by this converter is 4.68kW. In this project, the firing angle of DC converter is limited until because only in this range converter acts as DC converter and for firing angle , it acts as inverter.