2012
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Item A Novel Approach for Diagnosis of Breast Cancer using Ultrasound Imaging(Department of Electrical and Electronic Engineering, Islamic University of Technology (IUT), Board Bazar, Gazipur-1704, Bangladesh, 2012-11-15) Quader, NiamulBreast cancer continues to be the most occurring cancer in women around the globe. With advancements in medical procedures, breast cancers are now virtually treatable in their early stage. Early detection, in turn, is vastly improved with community-wide organized sustainable programs. However, such schemes demand resources, and sizable amount of fund is being wasted for biopsy of benign lesions. Ultrasound imaging, because of its low ionization, effectiveness in diagnosing lesions of younger women and lesser resource intensiveness makes it a viable option for mass population programs. It has been shown to be effective in prevention of significant number of unnecessary biopsies. Thus, ultrasound imaging modality remains a prominent tool for diagnosis of breast cancer. Rigorous work is being done to improve overall imaging modality. In light of breast cancer, quantization of acoustic and morphometric features has proven to give good Receiver Operating Characteristic (ROC) area performance. However, ambiguity may still be there at concluding a lesion to be benign. The natural trend for such scenarios is the follow-up checkups recommended by experts. With thousands of follow-up checkups occurring each year, the need for a systematic study is imminent. We develop an effective algorithm that systematically processes over-time-data with the use of thin plate spline smoothing. This is followed by systematic categorization of different sets of physiological changes in light of benign and malignant lesions. Finally a versatile community wide scheme is outlinedItem Development of an Adaptive Neuro-Fuzzy Controller for Speed Control of Induction Motor Drives(Department of Electrical and Electronic Engineering, Islamic University of Technology (IUT), Board Bazar, Gazipur-1704, Bangladesh, 2012-08-30) Azim, Md. RiyasatRobust and precise speed control is of critical importance in high performance drive applications. Control schemes for AC machines are complicated as compared to DC machines since they exhibit nonlinear relationships between process variables e.g. speed and manipulated variables e.g. current, torque etc. Direct torque control (DTC) scheme offers faster and simpler control of AC machines with high dynamic performance but without extensively using coordinate transformations and hence with lesser computational burden on the processor. Artificial intelligent controllers (AIC) are capable of overcoming the limitations of the mathematical model dependent conventional fixed gain and existing adaptive controllers. In this thesis, an adaptive neuro-fuzzy inference system (ANFIS) based controller is proposed to improve the dynamic behavior of DTC based induction motor drive which offers the combined advantages of the flexibility of fuzzy logic and adaptability of neural networks. Hence the developed adaptive neuro-fuzzy controller can be utilized to minimize the effects of unavoidable system disturbances such as, system parameter variations, sudden impact of load changes etc. Since the use of intelligent controllers are very limited in the drives industry due to the relevant computational burden on the microprocessor, therefore, in order to reduce the computational burden, linear linguistic variables with an optimum number of membership functions have been selected for the adaptive neuro-fuzzy controller developed in this thesis. The effectiveness of the proposed NFC based DTC scheme of the IM drive is consolidated through the development of a simulation model using MATLAB/Simulink. The results obtained from the simulation of the proposed system are compared with the results from simulation of the same system using conventional proportional integral (PI) controller. The results have shown promising improvements both in the transient and steady state responses of the system. Further, as an integral part of the thesis, a fuzzy logic controlled dynamic voltage restorer (DVR) system has been developed in order to protect the induction motor drive system from the power quality problems (like- voltage sag, swell etc.). The DVR system was developed and simulated in MATLAB/Simulink environment to verify its functionality. The simulation results have confirmed the ability of the DVR system to perform at an expected level when used in conjunction with the induction motor drive. The DVR system kept the induction motor drive performance intact under both symmetrical and asymmetrical system fault conditions.Item A novel approach for diagnosis of breast cancer using ultrasound imaging(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Quader, NiamulBreast cancer continues to be the most occurring cancer in women around the globe. With advancements in medical procedures, breast cancers are now virtually treatable in their early stage. Early detection, in turn, is vastly improved with community-wide organized sustainable programs. However, such schemes demand resources, and sizable amount of fund is being wasted for biopsy of benign lesions. Ultrasound imaging, because of its low ionization, effectiveness in diagnosing lesions of younger women and lesser resource intensiveness makes it a viable option for mass population programs. It has been shown to be effective in prevention of significant number of unnecessary biopsies. Thus, ultrasound imaging modality remains a prominent tool for diagnosis of breast cancer. Rigorous work is being done to improve overall imaging modality. In light of breast cancer, quantization of acoustic and morphometric features has proven to give good Receiver Operating Characteristic (ROC) area performance. However, ambiguity may still be there at concluding a lesion to be benign. The natural trend for such scenarios is the follow-up checkups recommended by experts. With thousands of follow-up checkups occurring each year, the need for a systematic study is imminent. We develop an effective algorithm that systematically processes over-time-data with the use of thin plate spline smoothing. This is followed by systematic categorization of different sets of physiological changes in light of benign and malignant lesions. Finally a versatile community wide scheme is outlined.Item Development of an adaptive neuro-fuzzy controller for speed control of induction motor drives(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Azim, Md. RiyasatRobust and precise speed control is of critical importance in high performance drive applications. Control schemes for AC machines are complicated as compared to DC machines since they exhibit nonlinear relationships between process variables e.g. speed and manipulated variables e.g. current, torque etc. Direct torque control (DTC) scheme offers faster and simpler control of AC machines with high dynamic performance but without extensively using coordinate transformations and hence with lesser computational burden on the processor. Artificial intelligent controllers (AIC) are capable of overcoming the limitations of the mathematical model dependent conventional fixed gain and existing adaptive controllers. In this thesis, an adaptive neuro-fuzzy inference system (ANFIS) based controller is proposed to improve the dynamic behavior of DTC based induction motor drive which offers the combined advantages of the flexibility of fuzzy logic and adaptability of neural networks. Hence the developed adaptive neuro-fuzzy controller can be utilized to minimize the effects of unavoidable system disturbances such as, system parameter variations, sudden impact of load changes etc. Since the use of intelligent controllers are very limited in the drives industry due to the relevant computational burden on the microprocessor, therefore, in order to reduce the computational burden, linear linguistic variables with an optimum number of membership functions have been selected for the adaptive neuro-fuzzy controller developed in this thesis. The effectiveness of the proposed NFC based DTC scheme of the IM drive is consolidated through the development of a simulation model using MATLAB/Simulink. The results obtained from the simulation of the proposed system are compared with the results from simulation of the same system using conventional proportional integral (PI) controller. The results have shown promising improvements both in the transient and steady state responses of the system. Further, as an integral part of the thesis, a fuzzy logic controlled dynamic voltage restorer (DVR) system has been developed in order to protect the induction motor drive system from the power quality problems (like- voltage sag, swell etc.). The DVR system was developed and simulated in MATLAB/Simulink environment to verify its functionality. The simulation results have confirmed the ability of the DVR system to perform at an expected level when used in conjunction with the induction motor drive. The DVR system kept the induction motor drive performance intact under both symmetrical and asymmetrical system fault conditions.Item Design and analysis of a model predictive unified power flow controller (MPUPFC) for improving power system stability(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Shahriar, Md. ShoaibThis thesis addresses model predictive controller (MPC) as an effective solution for improving the oscillations in a single machine infinite bus (SMIB) power system connected with a FACTS device named unified power flow controller (UPFC). UPFC is mainly used in the transmission systems which can control the power flow by controlling the voltage magnitude, phase angle and impedance. Linearized model of UPFC connected with SMIB system is modeled by five state equations. System oscillations of the plant are attempted to be controlled with power system stabilizer (PSS) and proportional integral (PI) controller. MPC was introduced to damp out the oscillations to improve the performances those of obtained using PSS and PI controller. As a controller, MPC not only provides the optimal control inputs, but also predicts the system model outputs to reach the desired goal. So, model predictive unified power flow controller (MPUPFC), a combination of UPFC and MPC along with proper system model parameters can provide a satisfactory performance in damping out the system oscillations in order to obtain a stable system. Simulation is done in Matlab simulation software. Responses are shown for four different states controlling four different control signals of UPFCItem Performance analysis of model predictive controller in non linear applications(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Ridwan, Abdur RaquibThis thesis is concerned with depicting the performance of MPC as a controller in nonlinear systems covering various fields of engineering. The Adaptive PID controller is used as the generic means of controller comparison. Main Emphasis and theme of this thesis is to visualize the performance of MPC as a controller for the flight control of the Micro Aviation Vehicle Ornithopter. The velocity, altitude and angular position are taken as the flight outputs to be controlled. A two dimensional model of the ornithopter is selected because it accommodates the inseparability of thrust and lift in its system which is instrumental for describing the flight operation of the ornithopter. Both the acceleration phase and steady state cruise motion control of the ornithopter is considered. The entire nonlinear mathematical model describing the equations of motion of the ornithopter is simulated in the Simulink Environment of the Matlab Software. The performance of the Model Predictive Controller for the flight control of MAV ornithopter is evaluated by comparing the responses with that of an Adaptive PID controller. Although a very improved and significant flight control of the ornithopter is possible with the Model Predictive Controller, a disturbance prone scenario, changing wind direction and speed is needed to completely visualize the impact of Model Predictive Controller in the flight control of an ornithopter. Moreover a better system model comprising a three dimensional mathematical model is required to successfully proceed with further altitude and velocity control. Other directional outputs such as the angular velocity, acceleration can also be investigated. Hence this thesis can be considered as the basis of properly understanding the control mechanism of the Model Predictive Controller and finally would serve as the platform from which the flight control of ornithopter can be investigated with Model Predictive Controller under more realistic and practical instances in which the ornithopter needs to be controlled.Item Design and analysis of a wideband microstrip antenna for high speed WLAN(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Al-Arif, S. M. Masudur RahmanThe wired local area network is becoming wireless day by day. The allocation of frequency spectrum for this Wireless LAN is different in different countries. This presents a myriad of exciting opportunities and challenges for design in the communications arena, including antenna design. The high speed WLAN has many standards and most antennas available do not cover all the standards. The objective in thesis is to design a suitable antenna that can be used for high speed WLAN application. The primary goal is to design antenna with smallest possible size and better polarization that covers all the high speed WLAN standards ranging from from 4.90 GHz to 5.82 GHz. Many works are going on throughout the world in field of antenna designing. Recent works on this field is studied in this thesis to find out most suitable antenna shape for the specific application. Zeland’s IE3D simulation software has been used to design and simulate antenna for WLAN frequency band. A parametric study has been presented in process to the designed antenna for an effective bandwidth of 4.9- 5.825 GHz. Return loss -10 dB or lower is taken as acceptable limit. Finally single E shape microstrip patch antenna having a dimension of 24×19 mm2 is demonstrated with a frequency band of 4.89 GHz to 5.83 GHz. The antenna presents a good current distribution and radiation pattern for all four standards of WLAN that falls inside this frequency range.Item Development of a smart controller for a switched reluctance motor drives(Department of Electrical and Electronic Engineering, Islamic University of Technology, 2012-11-15) Hasan, Md RezaulNowadays, switched reluctance motors (SRMs) attract more and more attention. Switched reluctance machines have emerged as an important technology in industrial automation. They represent a real alternative to conventional variable speed drives in many applications. It not only features a salient pole stator with concentrated coils, which allows earlier winding and shorter end turns than other types of motors, but also features a salient pole rotor, which has no conductors or magnets and is thus the simplest of all electric machine rotors. Simplicity makes the SRM inexpensive and reliable, and together with its high speed capacity and high torque to inertia ratio, makes it a superior choice in different applications. However, the control of the SRM is not an easy task. The motor flux linkage appears to be a nonlinear function of stator currents as well as rotor position, as does the generated electric torque. Apart from the complexity of the model, the SRM should be operated in a continuous phase-to-phase switching mode for proper motor control. This makes the control of SRM a tough challenging. This thesis attempts to first create a MATLAB model of multiphase SRM using the equations governing the dynamic behavior of linear inductance profile SRM. Based on this model, an example case study of single phase SRM operation has been. Small signal analysis of linearized single phase SRM was simulated. Performance analysis of the speed control loop, current control loop and overall SRM drive using PI controller was simulated in MATLAB environment and later all those were simulated again after PI controller was tuned by genetic algorithm. Performance improvement of genetically tuned PI controller is proved in this thesis.