بایگانی بخش thesis

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Ali Akbar Shams Baboli

Improving the Face Recognition Accuracy with the new method Multilinear Discriminant Analysis(MDA) Abstract With the improvement of communication and identification and determination of people identity problems for achieving the information, transfer the money and controlling the import and exporting the people of country and different places become important topics to invest in. Biometrics is methods to automatically verify or identify individuals using their physiological or behavioral characteristics. The necessity for personal identification in the fields of private and secure systems made face recognition one of the main fields among other biometric technologies. The importance of face recognition rises from the fact that a face recognition system does not require the cooperation of the individual while the other systems need such cooperation. Feature extraction methods try to reduce the feature dimensions Used in the classification step. There are especially two methods used in Pattern recognition to reduce the feature dimensions; Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA). These algorithms transform the input image data into a 1-D vector, which ignores the underlying data structure so these methods suffer from curse of dimensionality and often leads us to the small sample size problem. For solving these problems we proposed a new algorithm MDA that transform the image into a tensor with its own order. MDA with optimizing the new criterion, DTC, achieves multiple subspaces that the number of these subspaces determined with the order of the tensor. Performance of this algorithm is evaluated with 3 standard databases. With the respect to these results, our proposed algorithms improve the face recognition accuracy and the time of finding these optimum results and also avoiding the curse of dimensionality and the SSS problem. Student : Ali Akbar Shams Baboli Superviser: Dr. Rezai rad Defense date : Sat. 14/12/1389 Time :12:30 Place: class 303

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Seyyed Mohammad Sadegh Moosavi

Department of Electrical Engineering M.Sc. Thesis Defense 269 Simulation of Iris Recognition Systems by Using Active Contours in Segmentation Stage abstract A biometric system provides automatic recognition of an individual based on some sort of unique feature or characteristic possessed by the individual. Biometric systems have been developed based on fingerprints, facial features, voice, hand geometry, handwriting, the retina, and the one presented in this thesis, the iris. Biometrics based on iris has been widely used in recent years because of the useful features of iris. The iris recognition system is to be composed of a number of sub-systems, which correspond to each stage of iris recognition. These stages are segmentation – locating the iris region in an eye image, normalisation – creating a dimensionally consistent representation of the iris region, and feature encoding – creating a template containing only the most discriminating features of the iris. The input to the system will be an eye image, and the output will be an iris template, which will provide a mathematical representation of the iris region. The segmentation stage is critical to the success of an iris recognition system, since data that is falsely represented as iris pattern data will corrupt the biometric templates generated, resulting in poor recognition rates. The unacceptable performance of traditional segmentation methods like Hough Transform in boundary detection leaded to developing Active Contours. Hence, current research is directed toward resolving the drawbacks of some active contours such as Balloon and Greedy in order to segment iris images. In fact, three different Iris Recognition systems have been developed based on the mentioned active contours as well as Hough transform. The simulation results show that the proposed active contours yield better results than Hough transform from both view points of Accuracy and time. Besides, the employed data-base is CASIA Iris Database. Student: Seyyed Mohammad Sadegh Moosavi Supervisor: Dr. Ahmad Ayatollahi Referees: Dr. G. Rezaei-Rad , Dr. S. B. Shokoohi , Dr. M. H. Ghasemian-Yazdi Defense Date: Saturday, March, 5, 2011 11 AM Location: Class No. 303, Department of Electrical Engineering

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Seyed Mohammad Seyedzadeh

FACULTY OF ELECTRICAL ENGINEERING Master of Science Thesis Defence Using AES Algorithm to Improve Fault Tolerance in Encryption of Satellite Images Abstract Security information in the satellite images is rapidly growing and has been the focus of many researches. Illegal access to satellite networks for the purpose of accessing satellite data has proved the vulnerability of most of these data to Hacking threats. To overcome these threats, the security of satellite data can be achieved by encryption. Currently, most of the Earth Observation (EO) Satellites are equipped with the onboard encryption system for protection of the data that are transmitted to the earth Stations. Regarding to the fact that satellites operate in the Harsh Radiation Environment, each electronic onboard system and typically encryption processors are prone to Single Event Upsets. To increase the Fault Tolerance of the AES algorithm in the encryption of satellite image, this thesis proposes architecture based on the Hamming code error detection and correction method. This architecture can detect and correct single bit fault through the encryption process. The architecture uses a module for the detection and correction of faults in each transformation in each round of the AES algorithm. This module detects and corrects the fault that occurs during the encryption. The fault propagation in the proposed architecture is simulated by a java program and then validated in 5 operation modes of the AES algorithm. Synthesizing of this architecture was done by the ISE software. The value of Efficiency, Overhead, Throughput, Maximum Frequency, and Power were 1.1 Mbps/slice, 16%, 24.2 Gbps, 188.718 MHz, and 1232 mW respectively. These results show that the proposed architecture has more satisfactory performance than the other architectures mentioned in the thesis. Student : Seyed Mohammad Seyedzadeh Supervisor: Dr. Sattar Mirzakuchaki Referees: Dr. Houshang Hasibi, Dr. Karim Mohammadi, Dr. Hadi Shahriyar Shahhoseini Date of Defense: March 5, 2011 Time:13 Place: Class 305 Faculty of electrical engineering

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Meisam Rezaeian

Department of Electrical Engineering Session Defense of MSc Thesis 269 MicroGrid Online Management Using Multi-Objective Optimization Abstract: The MicroGrid (MG) concept assumes a cluster of loads and microsources operating as a single controllable system that provides both power and heat to its local area. This thesis presents scheme of optimal management of microgrid using multi-objective genetic algorithms (MOGA) aimed at reduction of cost and emission with satisfying constraints, electrical and heat loads. microgrid structure, system component models, objective functions and problem solving method is described. Proposed MG consists of a diesel generator, a fuel cell, a micro turbine, a wind turbine, a photovoltaic array and battery storage. Recovered heat by micro-turbine and heater can be used to supply heat demand. Also heat penalty, hourly revenue and outgo from sold and purchased power added to the cost function. The main goal of this thesis is to demonstrate impacts of using CHP system, heat penalty and also sale and purchase price changes on management and operation of microgrid. Therefore optimization problem solves as multi-objective for several scenarios to supply loads and satisfy constraints during twenty-four hour period. Simulation by MATLAB demonstrates the accuracy of results on proposed microgrid. Student: Meisam Rezaeian Advisor: Dr. Sh. Jadid Opponents: Dr. S. H. Hosseini, Dr. M. Kalantar, MSc. A. Kazemi Date: Wednesday, 1389/12/18 Time: 1-3 pm Location: Department of Electrical Engineering Building, Class 303.

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Abolfazl Mosaddegh

Electrical Engineering Department Master of Science Defense Meeting Determination of DG Capacity to Maintain the Coordination between Fuses and Reclosers in Order to Prevent the Reliability Degradation Abstract The Structure of distribution systems are conventionally radial and for this reason, the downstream feeders of the network are just supplied with the main available source and also the protection systems are designed with respect to radial structure of the networks. If the fault occurred in these networks, the fault current is solely fed by one source. Connecting Distributed Generations (DGs) to networks, its structure is not radial anymore and in the fault situations, the fault current is fed by all available sources i.e. DGs participate to supply the fault current. In this dissertation, two strategies are introduced to maintain the coordination between fuses and reclosers in distribution systems. In the first strategy, the DGs capacity in the network is determined whereas with these capacities, the coordination between protective components of fuse and recloser is maintained correctly. In the second strategy, the protective settings of micro-processor reclosers are changed in order to keep the coordination of protective devices with maximum DGs capacity. The micro-processor reclosers can be performed by multiple operation curves while the simple reclosers only operate with one operation curve. Choosing the test system RBTS bus 2, the simulations are done and the results are derived for mentioned test system. Finally, the reliability calculations are presented and compared in three cases of without any DGs in the network, the network in presence of DG with respect to strategies (coordination is maintained) and the network in presence of DG with maximum DG capacity (miscoordination may be occurred). The results show the effect of maintaining the coordination of protective devices on reliability of distribution systems. By: Abolfazl Mosaddegh Supervisor: Prof. Ahad Kazemi Referees: Prof. Seyyed Mohammad Shahrtash; Prof. Davood Arab Khaburi; Prof. Seyyed Hosein Hoseinian Date of Defense: Monday March 07, 2011 Time: 17-19 Place: Class 303 Electrical Engineering Department

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چهارشنبه ۱۱ اسفند ۱۳۸۹ -

Arash Alizadeh Vandchali

Design and Simulation All Optical Switches Based on Nonlinear Photonic Crystal Device Abstract The main purpose from designing photonic devices is increasing the effective use of optic fibbers bandwidth. One of the devices to achieve this is using photonic switch. Photonic switches are variously used to increase switching Speed. Recently, photonic crystal switches are variously fascinated due to specific characteristics of photonic crystals in controlling and conduction of light. Here an all optical photonic crystal switch based on MZI has been proposed to achieve maximum switching speed and lowest consuming power. The amount of nonlinearity of each switch can be a good factor in determining its quality and performance. To increase the nonlinearity, here we put a polymeric material with high nonlinearity Kerr effect in one arm of the MZI waveguide Kerr nonlinear index of n2=3 × 10-15(m2/W). Necessary analysis has been done to obtain switch parameters such as length of the arm and required power for switching. Since having a bend with low dissipation is considered in switch design, rectangular structure has been used. With considering this fact that photonic crystal wave guide based on rode has great band width and great group speed velocity. Therefore general structure is selected as rectangular photonic crystal with dielectric rods in background of air. All the results have been verified through the mathematical equations and simulations with two numerical techniques: FDTD and PWE. In most cases identifying the band structure of one or some parameters are important for optimizing photonic crystal designs. Material used here is SiGe and has refractive index of n0=3.6. To find the optimized value for lattice, the centre of this band gap considered as designed frequency, here maximum band gap lattice constant is a=0.602?m then r=0.155 × a=0.0933?m. First we designed 1 × 1 all optical switch based on MZI 1By doing calculations, switching occurs at I= 7(W/mm). Direct coupler has been designed to eliminate ring mode in MZI output. Designed coupler has new structure with vertical bends. Next we designed one 1 × 2 that switching occurs at I= 11(W/mm). Finally we designed one 2 × 2 switch, which switching occurs when input intensity of light exceeds 4.7W/?m and essential phase difference for switching obtained when the intensity of input light reaches 6.5W/?m . These switches have capability to have good performance in integrated photonic crystal circuit and also applications in WDM lattice. STUDENT: Arash Alizadeh Vandchali Supervisor: Dr.Shahram Mohammad nejad Defence date:11/12/89 time:15:00

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پنجشنبه ۲۸ بهمن ۱۳۸۹ -

Mohammad Akbari

Electrical Engineering Department Master of Science Thesis Defense Session 269 Performance Improvement of FHSS-Based Cognitive Radio Network in The Presence of Jamming, Using Secure Cooperative Spectrum Sensing Techniques Abstract A serious threat to cognitive radio networks which sense the spectrum in a cooperative manner is the transmission of false spectrum sensing data by malicious secondary nodes. This enforces the system to acquire authentication. This issue is beyond regular authentication of data origin which assurances that messages are indeed from who they claim they are from. Actually, the decision maker needs to determine the reliability or trustworthiness of the shared data. This thesis utilizes the potential benefits of cooperative spectrum sensing method in a way that it can become applicable when the CR nodes encounter wireless channel uncertainty and some CR nodes that behave maliciously. To this end, after estimating the channel and the PU signal statistics accurately, they are employed to determine the likelihood of CR sensing reports in a MAP hypothesis test scheme for decision about channel occupancy. Also, a computational trust evaluation algorithm is proposed to determine the trustworthiness of each CR user's data and eliminate the effect of SSDF attackers. Defense against Primary User Emulation Attacker (PUEA) is the second issue that is considered in this thesis. To this end, an adaptive transmission technique for frequency-hop packet transmission is proposed and its performance is evaluated for certain channels with unknown attacker’s signal parameters. The power in the transmitted signal and the rate of the error-control code are adapted in a way that provides an energy-efficient communications. The performance of the adaptive transmission system is evaluated for channels with some PUE attackers that occupy some fraction of the spectrum band with time-varying partial-band interference and propagation loss. By: Mohammad Akbari Supervisor: Dr. Abolfazl Falahati Reference Committee: Dr. M. Soleimani; Dr. B. Abolhasani; Dr. A.F. Ahmadi Date of Defense: Saturday, February 26, 2011 Time: 3.0 pm Place: Class 303, Electrical Engineering Department

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پنجشنبه ۲۸ بهمن ۱۳۸۹ -

Milad Ghazal

Iran University of Science and Technology School of Electrical Engineering 269 Robust Observer Design for Stator Winding Fault Detection in Induction Motors Abstract In this thesis, two methods are proposed to detect stator winding fault in induction motors. The first method is based on a model based approach and a robust observer is presented to detect stator winding faults despite the load variations. Since the proposed observer should be robust, Unknown Input Observer (UIO) is used as robust observer. In the UIO design procedure, for flexible design, the stator currents and speed of induction motor are assumed as measurement signals. After designing a nonlinear UIO, an Extended Kalman Filter (EKF) is used for speed estimation of the induction motor. Therefore, speed measurement is relieved. Simulation results of stator winding fault with various short-inter-turns are shown to evaluate ability of the proposed approach. Finally, an experimental study on a 5-hp induction motor is performed under simulated short-turn stator winding. The results verify that faults can be reliably detected, and hence the proposed method can be used to improve safety and efficiency of the motors in industrial plants. In the second method, a Wiener Filter method has been proposed for detecting stator winding fault in induction motors. This filter is used for estimating and removing useless components from stator currents in order to detect stator winding fault with high reliability. Since the Park’s vector modulus is sensitive to abnormality in three-phase stator currents, it will be used for detection purposes. Finally, the validation of proposed method will be verified by experimental data from a 5-horespower induction motor. Student: Milad Ghazal Supervisor: Dr. Poshtan Referee teachers: Dr. Shahri , Dr. Momeni Date of defense:27 Feb 2011 Location: 303 room

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چهارشنبه ۲۰ بهمن ۱۳۸۹ -

AbbasAli kazemian

Iran University of Science and Technology Electrical Engineering Department Defense for Degree of Master of Science in Electronic 269 Using Partial Differential Equations (PDEs) FOR Image Denoising Abstract: In this article, a new method is presented for the elimination noise from images, which makes use of the anisotropic diffusion equations and the wavelet transformation. In the existing methods for image noise elimination that are based on the wavelet threshold marking, the existing approximate coefficients in the wavelet transformation, which contain the overall information of the image, are not affected by threshold demarcation. Therefore, the final image (obtained after the noise elimination) will have a limited improvement. Since noise affects both the detail and approximate coefficients of the image, we apply the noise elimination technique based on the anisotropic diffusion equations, on the image's approximate coefficients in order to alleviate the problem associated with the wavelet-based noise elimination methods. By using the anisotropic diffusion equations, the existing noise data in this sub-band will also be preserved. STUDENT: AbbasAli kazemian Supervisor: Dr.Ahmad Ayatollahi Defence date:27/11/89 time:16:00

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سه شنبه ۱۹ بهمن ۱۳۸۹ -

Alireza Ghorbani

Iran University of Science and Technology Electronics Department Degree of Master of Science in electronics Defense session Design a current operational amplifier with high CMRR and low power Current-Mode processing has attracted great attention in recent decades. Current –Mode circuits are distinguished from voltage-mod ones in two main criteria; 1) Instead of voltage, they process current signals as the main variable and data. 2) Ideally there should be no high impedance nodes in their signal paths. In this thesis the current operational amplifier are introduced and their important specifications are noted. Moreover an overall review is performed on the researches that dealt with improvement in specification of this block. In this thesis various methods are proposed to improve the specification of current operational amplifier which any one is introduced to improve some of the current operational amplifier specifications. Designing of the current output stage with ultra high output impedance (13GΩ) , ultra low power consomptions (86µW) and a current follower with very low input resistance (38mΩ) , low power consomptions (145µW) and high CMRR (110dB) are some of the results of this thesis. HSPICE simulator is used to perform simulation and the simulation results are given to prove the validity of works. By: Alireza Ghorbani Supervisor: Dr. Seyed Javad Azhari Jury : Dr. Shamsi; Dr. Ayatolahi; Dr. Abrishamifar Sunday 6th February 2011,Time:13:00 Seminar room, first floor, electrical and electronic engineering faculty, Iran university of science and technology (IUST)

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یکشنبه ۳ بهمن ۱۳۸۹ -

Mahdi Anvari

Electrical Engineering Faculty Defense of Master Thesis 269 The Analysis & Simulation of the Power Systems of Tabriz POLYNAR Factory Abstract This project is studying the harmonic impedance of Tabriz POLYNAR Factory. In the first step, the Voltage and Current of different loads in the factory are measured with special measuring devices. In the second step, the waveform of these measurands and their harmonic contents are extracted using MATLAB Simulink blockset. Then according to the extracted parameters, a suitable Load Model is selected and simulated in MATLAB Simulink blockset. Finally, the results of these two methods, are compared and their equivalent Harmonic impedance and Resonance impedance are extracted. Graduate Student : Mahdi Anvari Supervisor : Abbas Shoulaei (Professor) Jury : Alireza Jalilian ,Davood Arab Khaboori (Assistant Professor) Reza Gandhari (Assistant Professor) Date and Time : Sunday , 2011-01-24 at 14:00 Location : Electrical Engineering Faculty, Room No. 206

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یکشنبه ۳ بهمن ۱۳۸۹ -

Vahid Faraji

Departman of Electrical Engineering Master of Science Defense Simulation of Direct Torque Control for Induction Motor Drive system Fed by Indirect Matrix Converter Abstract In thesis proposed a direct torque control (DTC) scheme for induction motor drive system fed by indirect matrix converter. DTC is a high performance motor control scheme with fast torque and flux response. However, the main disadvantage of conventional DTC is electromagnetic torque ripple. By suitably selecting switching pattern, conventional problem of DTC such as electromagnetic torque and flux ripple of the motor is effectively reduced. Using this switching strategy, the advantages of the DTC schemes and the benefits of the indirect matrix converter can be combined. New methods of improving torque ripple are introduced in this thesis. In the rectifier stage, in order to reduce losses caused by circuit snubber the rectifier four-step commutation method is employed. To improve the dynamic behavior of motor, Active Learning Method (ALM) is implemented on the DTC. The ALM uses its own modeling technique called the ink drop spread (IDS) method. Since the indirect matrix converter has an intermediate dc link, the control process can be separated into rectifier stage modulation and inverter stage modulation. Indirect space vector modulation (ISVM) for input current is applied on the rectifier bridge, while the inverter and motor can be seen as constant current load in DC link and ISVM for output voltage is applied on the inverter bridge. The modulation processes of rectifier stage and inverter stage are considered simultaneously. By : Vahid Faraji Supervisor : Dr. Davood Arab Khaburi Jury: Dr. Mokhtari, Dr. Vahedi, Dr. Kalantar Date of Defense: Saturday: januery 29 2011 Room No. 206

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یکشنبه ۳ بهمن ۱۳۸۹ -

Mahdi Taheri

Department of Electrical Engineering M. Sc. Thesis Defense 269 Routing Security in Wireless Ad Hoc Networks Mobile ad hoc networks are a special type of mobile wireless networks where a collection of mobile network devices from a temporary network without any aid of an established infrastructure. However, the fact that there is no central Infrastructure and that the devices can move randomly gives rise to various kinds of problems, such as routing and security. Many algorithms are proposed for security in routing process for wireless ad hoc networks. Too much of secure routing protocol in ad hoc networks focused in authentication, and they disregarded the data confidentiality after rout discovery. Hence, in this thesis, we propose secure routing algorithm, named High Secure Routing Protocol in wireless ad hoc networks with two methods (HSAODV1 and HSAODV2). These protocols have two phases: In the first one, at the first step the source, destination and intermediate nodes authenticate by use of digital signature and asymmetric algorithms, after in the next step, the protocol utilizes one way function for data confidentiality increased. In the second one, at the first step the source, destination and intermediate nodes authenticate by use of one way hash function, the next step of the HSAODV2 is same as HSAODV1 with little different. We base the design of HSAODV1 and HSAODV2 protocols in part on the AODV ad hoc network routing protocol. Our protocols are robust against multiple routing attacks such as blackhole attack. In order to assess the functionality of this algorithm, the security matrix and the normalized routing overhead are evaluated for proposed method in three steps. For simulating the algorithms NS-2 network simulation tool is used. In the first step of simulation, the packet delivery ratio, average end to end delay and normalized routing overhead are evaluated for proposed algorithms. In the second step of simulation, the blackhole attack is simulated in AODV, HSAODV1 and HSAODV2 protocols then the security matrix and the normalized routing overhead are compared for these protocols and AODV. In the last step of simulation for performance analyze, the proposal algorithms are compared with AODV and SAODV protocols . Student: Mahdi Taheri Supervisor: Dr. Majid naderi Adviser: Dr. H. Taheri, Prof. K. Mohammadi, Dr H. S. Shahosseini Defense Date: Monday 31 January Time: 2:30 PM Location: Class No. 204, Department of Electrical Engineering

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چهارشنبه ۲۱ مهر ۱۳۸۹ -

Fatemeh Muhammadi- Monavar

Iran University of Science and Technology Electrical Engineering Department Master of Science Defense Notice 269 Bandwidth Increment of Microstrip Patch Antenna using AMC Structures Abstract An invasive weed optimization ( IWO) algorithm design methodology is presented for improving the bandwidth of a microstrip patch antenna using jerusalem cross-shaped frequency selective surfaces (JC-FSSs). The IWO is employed to obtain optimal dimensions of the patch antenna and JC-FSS element in order for the whole structure to work at 5.8GHz with consideration of the gain. It is shown that choosing an appropriate particular shape like jerusalem cross, for the FSS element rather than a pixelized grid geo metry, allows for a superior antenna design in term of computational efficiency. Simulation results show that for this novel design, return loss bandwidths of about 10.44% have been achieved. However, considering the gain to be greater than 5 dB reduces the bandwidth to 8.41%. In general by introducing this novel jerusalem cross artificial magnetic conductor (JC-AMC) in lieu of the conventional perfect electric conductor (PEC) ground plane, the bandwidth enhancement of about 60% has been obtained. In order to check the competence of the design, the antenna-AMC structure is also synthesized. This antenna shows measured relative bandwidth of BW = 10.41%. Keywords : Artificial magnetic conductor (AMC), invasive weed optimization (IWO) algorithm, wideband patch antenna, jerusalem cross-shaped frequency selective surfaces (JC-FSSs) By: Fatemeh Muhammadi- Monavar Supervisor: Dr. Nader Komjani Decision Group: Dr. Jalil Rashed- Mohasel; Dr. Ahmad Chaldavi; Dr. Majid Tayarani Defense Date: October 18, 2010 (Monday) Defense Time: 17:30 Location: Room No. 305 ( Electrical Engineering Department)

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چهارشنبه ۲۱ مهر ۱۳۸۹ -

Arvin Morattab

Faculty of Electrical Engineering Announcement for M.Sc Thesis defense session 269 a distributed model predictive control design for formation flying of spacecraft Abstract Spacecraft formation flying is defined as a group of more than one satellite which cooperates together in a common space mission while maintaining a specific geometrical formation in space. This will provide the possibility of doing complex space missions using small, rigid and cheap micro and nano satellites with more accuracy in comparison with previous huge, flexible and expensive ones. Despite its advantages, some concerns comes about with new technology of formation flying which are formation maintenance, fuel minimization and equalization, practical limitations for satellites and formation, collision avoidance between spacecrafts during maneuvers, decrease of communication bandwidth, computation reduction and robustness to probable faults in system. In this thesis we first review different dynamical models and control methodologies for formation flying of spacecrafts. Comparing these control methods, we choose distributed model predictive control algorithm as a suitable control strategy and show that it satisfies all properties of a desirable formation flying controller. Also to prevent satellites form collision between two successive sample times during a maneuver, we propose a new method to overcome the problem. Finally the proposed control algorithm is validated through simulations on a network structure and the results show the effectiveness of the method. Keywords: spacecraft formation flying, model predictive control, distributed control, collision avoidance, fuel equalization Student: Arvin Morattab Supervisors: Dr. Mohamadreza Jahed Motlagh, Dr. Hossein Bolandi Advisor: Dr. Javad Poshtan Jury: Dr. Hamidreza Momeni, Dr. Mohammad Shahri Date of Defence: Saturday, October 16, 2010 time: 13:00 Location: Class No.305, new building of EE department

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چهارشنبه ۲۱ مهر ۱۳۸۹ -

Mohammadreza Ghazanchaei

Iran University of Science & Technology (IUST) Master Thesis Presentation Session 269 Modeling and Sensitivity Analysis of Cylindrical Hysteresis Motors Simple construction with conventional three phase stator windings, solid rotor hysteresis ring and self starting torque are the main features of hysteresis motors. These advantages make the hysteresis motor suitable for applications, such as compressors, pumps, timing, and recording equipment. Hysteresis motor is a synchronous motor that uses the hysteresis characteristics of the magnetic materials. It is known that the magnetic characteristics of the motor could be easily affected by hysteresis material, structural dimensions and winding distributions. To consider those effects, it would be desirable to adopt the finite element method (FEM). In almost previous studies, 2D finite element (FEM) techniques for simulating of hysteresis motors have been developed. In this thesis the performance characteristics of conventional and hybrid hysteresis motor through a 3D finite element analysis (FEA) is provided. Meantime, In this study effect of different parameter variation on performance characteristics of a prototype motor is investigated and optimal parameter quantities are extracted through a 3D finite element method (FEM). Based on output results of sensitivity analysis and with consideration on objective functions and constrains a new motor is produced with optimal parameters. In this study, the application of complex permeability concept is implemented in order to model the hysteresis loop in the shape of inclined ellipse. Finally, in order to validate the simulation an experimental set up is provided and output characteristics of conventional hysteresis motor are measured. Keywords : Conventional hysteresis motor , Finite Element Model, Complex Permeability, Sensitivity analysis Student: Mohammadreza Ghazanchaei Supervisor: Dr. Abolfazl Vahedi Examiners: Prof. Abbas Shoulaei, Dr. Alireza Jalilian, Dr. Javad Shokrollahi Moghani Dissertation presentation: Wednesday 20 October 2010 Place: Class 305, Electrical Engineering department

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دوشنبه ۲۹ شهریور ۱۳۸۹ -

Mojdeh Abdi Khorsand

Iran University of Science & Technology School of Electrical Engineering Degree of Master of Science in Electrical Engineering Determining the Optimal Amount of Reserves by Considering Wind Power Generation in Power System Using Stochastic Optimization Abstract This thesis presents a stochastic mixed-integer linear programming model by an emphasis on economic valuation of reserves in power systems with high penetration of wind power. The results are compared with the deterministic schedule of reserve requirement. The main purpose of this thesis is to determine a sufficient amount of reserve for a power system. This model considers the generators and network constraints. In this stochastic security model, Wind generation uncertainty is modeled through a set of scenarios representing all plausible realizations of this stochastic process. Each scenario has a probability based on a scenario tree that is located in objective function. The goal is to minimize the weighted-average generation cost over the entire scenarios. Also, To obtain optimal amount of reserves, the value of lost load and load shedding are considered in objective function. Additionally, this thesis focuses on the development of a model for interruptible load participation within the operating reserve in energy and reserve scheduling with high penetration of wind power. The characteristics of the procurement of interruptible load such as maximum interrupted time and minimum connected time, different offer in each IL’s agent, maximum and minimum IL’s quantity participation are explicitly considered. Moreover, A methodology for wind-thermal scheduling in a power system with high penetration of wind power subject to cost and air pollutants emission reduction is presented in this thesis. Because of simultaneous minimizing total operating cost and air pollutants emission, a Multiobjective Mathematical Programming (MMP) is introduced . The proposed approach is tested on a 3-buses system and IEEE-RTS system for 24 hours. The usefulness of the multiobjective wind-thermal approach was demonstrated through an IEEE 30-bus test system. The results showed that using the stochastic approach significantly reduces the reserves requirement and makes possible lower operation cost compared to the deterministic reserve criterion and the stochastic approach leads to a more efficient utilization of energy and reserve resources. Also, the participation of interruptible load in reserves market increases system security and decreases system operation cost. Finally, It is concluded that using multiobjective approach with aim of reducing total operating cost and air pollutant emission makes scheduling more efficient. By: Mojdeh Abdi Khorsand Supervisor: Dr. Hossein Heydari Date: Sunday 26-September-2010 08:00am

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دوشنبه ۲۹ شهریور ۱۳۸۹ -

Fatemeh Sadat Arzanforoosh

School of Electrical Enginnering Master of Science Dissertation Present 269 The Effect of Electromagnetic Waves on Cockroach Abstract Robot design and implementation for better human life has been under development for years; in recent years a new interest is developing for small size robots, and as a result some attention has been paid to the benefit of controlling small size insects for specific purposes. Bio-robotic is a new developing field to explore and employ new concepts in this area. First researchers started with stimulating small insects like cockroaches for their special capabilities; it was first begun with direct stimulation with special electrodes to investigate the response from insect. Direct stimulation has led to designing a chip controller which is attached to back part of the cockroach body. This method has its own drawbacks like the heavy weight of the chips for some kinds of insects, falling off the back of the cockroach and short battery life. Therefore, Indirect control and stimulation became of interest soon. A unique stimulation method which has been under research for some times is electromagnetic wave stimuli. Static electric fields, static magnetic field and radio frequency waves are among the stimuli waves. Here we used electromagnetic waves in the range of 100 to 500 MHz. Experiments conducted here showed that the cockroach is responding to the stimuli by avoiding the electromagnetic field. Increasing the frequency causes more abrupt avoidance by the insect, which may be the result of wave's impact on antennas dielectric constant . Keywords : Periplaneta cockroaches, electromagnetic waves, antennas equivalent circuits and dielectric constant. Student : Fatemeh Sadat Arzanforoosh Supervisor: Dr. Gholamali rezaii raad Dissertation Committee: Dr. M.H.Ghasemian, A. Erfanian Date: 31/6/89 Time: 11 Place: School of Electrical Eng. Seminar Room

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سه شنبه ۲۳ شهریور ۱۳۸۹ -

Seyyed Meysam Seyyed Barzegar

Electrical Engineering Department M.Sc Thesis Oral Defense 269 Electric Islanding Detection Using Negative Sequence Voltage Component and Wavelet Transform Abstract One of the challenging protection problems is distribution network islanding since may cause serious problems for network equipment specially distributed generators. As most basic treatment to protect networks facing islanding, islanding detection has been discussed in this dissertation in depth. Used method to do that is passive one. Passive method is characterized by measuring detection parameters at distributed generators terminals. Main used detection parameter is negative sequence voltage component. Regarding various network fluctuations occurring at different situations in terms of generation and consumption equilibrium, the accuracy of detection method may be impacted. Therefore, beside negative sequence voltage component employing synchronous generator field voltage, positive sequence impedance, voltage harmonics distortion factor and defining indices based on voltage wavelet transform output have been considered in order to distinguishing condition caused by islanding from other six network changes. Connect and disconnect loads and capacitor banks, symmetric and asymmetric faults, voltage fluctuations, and voltage notch are those changes which have been distinguished from network islanding in this dissertation. Since passive methods treat based on determining threshold limit for detection parameters, inaccurate determining of these limits may lead to incorrect results. As r result, pattern recognition methods have employed to overcome this problem and omitting threshold limit determining step. Use of Support Vector Machine (SVM) and Neural Network (NN) to classify trained data in island and non-island classes, have demonstrate the efficiency of abovementioned methods to detect island situation. Simulation results show that proper characteristic selection has a major effect on data classification capability. Student: Seyyed Meysam Seyyed Barzegar Supervisor: Dr. Shahram Jadid Jury Committee: Dr. Bathaee, Dr. Shahrtash, Dr. Kalantar Date: 22 September 2010 Time:13 Place: EE Department Seminar Room

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سه شنبه ۲۳ شهریور ۱۳۸۹ -

Mohammad Miranbeigi

Electrical Engineering Faculty MSC Oral Defence Notice 269 Design of Model Based Predictive Control for Supply Chain Management Systemsabstract A supply chain is a network of facilities and distribution entities (suppliers, manufacturers, distributors, retailers) that performs the functions of procurement of raw materials, transformation of raw materials into intermediate and finished products and distribution of finished products to customers. Between interconnected entities, there are two types of process flows: information flows, e.g., an order requesting goods, and material flows, i.e., the actual shipment of goods. The significance of the basic idea implicit in the model predictive control has been recognized a long-time ago in the operations management literature as a tractable scheme for solving stochastic multi period optimization problems, such as production planning and supply chain management, under the term receding horizon. A move suppression term that penalizes the rate of change in the transported quantities through the network increases the robustness of the control system. In this paper, we applied centralized model predictive controller and decentralized model predictive controller to both supply chain management systems dynamic models without information cycles and with it. Also we added a move suppression term to cost function that increase system robustness toward changes on demands. Through illustrative simulations, it is demonstrated that the model can accommodate supply chain networks of realistic size under deterministic and stochastic input disturbances. By: Mohammad Miranbeigi Supervisor: Dr. Aliakbar Jalali Advisor: Dr. Mohammadreza Jahedmotlagh Jury: Dr. Houman Sadjadian , Dr. Sajjad Ozgoli Defence date: 18/09/2010 Saturday Time: 12 am Where: Electronic Research Center

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سه شنبه ۲۳ شهریور ۱۳۸۹ -

Hamed Zekri

Iran University of Science and Technology Electrical Engineering Department MSC Oral Defense Notice 269 Cost-Causality Based Tariff Design for Distribution Networks with Distributed Generation Abstract The increasing penetration of DG in the power systems has changed the concept of the distribution networks. In traditional distribution networks, the costs of these networks were allocated only to demand customers, not generation because these networks were viewed as serving demand only. In this sense, traditional distribution networks were considered passive networks unlike transmission networks which serve both generation and demand and have always been considered active networks. The introduction of DG transforms a distribution network from a passive network into an active network. Present tari ff s schemes at distribution level have been conceived using the traditional concept of distribution. These tari ff s have been designed for networks which only have loads connected. These tari ff s that normally average costs among network users are not able to capture the real costs and benefits of some customers like DG. Consequently, traditional tari ff s schemes at the distribution level can a ff ect the competitiveness of DG and can actually stop its development. In this work a cost-causality based tari ff is proposed for distribution taking into account new distribution networks tend to be active networks. Two methodology based on the same philosophy used for transmission pricing are used. The first is nodal pricing for distribution networks, which is an economically e ffi cient pricing mechanism with which there is a great deal of experience and confidence from its use at transmission level. The second is an extent-of-use method for the allocation of fixed costs that uses marginal changes in a circuit’s current flow with respect to active and reactive power changes in nodes, and thus was called Amp-mile method. The proposed schema for distribution pricing results to give adequate price signals for location and operation for both generation and loads. This tariff schema considers the benefits of DG presence in distribution networks, and increases its revenue rather than classic tariff design. In fact, under the proposed tariff design, DG has rewarded for its contribution in line losses and usage reduction. By: Hamed Zekri Supervisor: Dr. Aliakbar Jalai Advisor: Dr. Shahram Jadid Jury: Dr. Mohammad Farrokhi, Dr. Masoud Tafreshi When: Date: Tuesday September 14th Time: 17:30 Where: Electronic Research Center

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سه شنبه ۱۶ شهریور ۱۳۸۹ -

Abbas Pahnabi

Department of Electrical Engineering MA Dissertation Defense Meeting Simulation and optimization of vector control of interior permanent magnet synchronous motors in order to increase efficiency Abstract This thesis has tried to casualties engine to achieve maximum efficiency, according to engine speed and torque acts to be minimum. In order to achieve this goal, the optimum amount of ‌ current components in rotor flux rotating machine base at any speed and load and specified as command values will be used. This analysis with using the parameters and all equations of machine losses will prove.Then Simulation results using this method with current control methods, and compared the advantages and disadvantages will be discussed. More Equations of vector control permanent magnet synchronous motor drive system, in the stator flux control and optimization system introduced in the efficiency of this machine is also studied. More The results of optimal control of internal permanent magnet synchronous motor efficiency in rotor flux machine d-q with stator flux results of this control system x-y will be compared. Student: Abbas Pahnabi Supervisor: Dr. Davod Arab Khaboory Jury: Dr. Alireza Jalilian, Dr. Abolfazl Vahedi, Dr. Mohammad Reza Zolghadri Time of Defense: 10 AM Date of Defense: 1389.6.30 Location: Seminar Hall of Faculty of Electrical

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سه شنبه ۹ شهریور ۱۳۸۹ -

Amir Mousa Haddadi

Iran University of Science and Technology Electrical Engineering Department M.Sc.Thesis Presentation Power Flow Control with Combination of Series FACTS Devices and Phase Shifter Abstract Because of the increasing demand for electric power and limitations of transmission expansion, optimal and safe usage of power systems is very important . Flexible AC transmission systems (FACTS) are suggested as useful and effective tools for realization of this goal. Although these devices have definitive merits but their usage is not widespread because of cost considerations, especially those with more complicated structure like unified power flow controller (UPFC). Thus new combinations of series FACTS controllers (like thyristor controlled/switched series capacitor) and phase shifter are studied in this thesis. These combinations are cost effective and their abilities are similar to that of UPFC. After introducing these new combinations, their steady-state and dynamic operation is analyzed. Transient stability constrained optimal power flow and dynamic stability assessment are used to show the effectiveness of introduced controllers. Power injection model of FACTS controllers is also extracted for steady-state analyses. A fuzzy logic controller is used in order to control dynamic operation of FACTS controllers. Results show that introduced controllers are very effective for steady-state and dynamic control of power systems. A computer program is developed to conduct optimal power flow with FACTS devices in different test systems and with different objective functions. Student: Amir Mousa Haddadi Supervisor: Dr. Ahad Kazemi Examining Committee: Dr. Tavakoli Bina, Dr. Shoulaie, Dr. Jalilian Date: Monday, 13 September 2010 Location: Electronic Research Center Time: 10:00 A.M.

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سه شنبه ۹ شهریور ۱۳۸۹ -

Bahamin Sabouti

Iran University of Science and Technology School of Electrical Engineering 269 Msc Thesis Oral Defense Notice Design and Simulation of a Systolic Arithmetic Unit for an Elliptic Curve Cryptographic Processor Abstract With increasing amount of sensitive transferred information through the Internet, network security and cryptography has become vital. Elliptic curve crypto systems which are based on finite field arithmetic due to less computation, less chip area, less required memory and high security have been used in smart cards, mobile phones, etc. Besides the high security encryption methods, high-speed encryption and decryption are also evaluation factors for an encryption system. The most important part of in crypto processors is used finite field arithmetic unit. In this thesis, an arithmetic unit for use in fast and efficient elliptic curve crypto-processor has been designed in which units have been designed to be systolic. Student: Bahamin Sabouti Supervisor: Dr. Hadi Shahriar Shah Hosseini Referees: Dr. Mahmoud Salmasi Zadeh; Dr. Majid Naderi; Dr. Ali Sadr Date: Monday 13-Sep-2010 Time: 9 AM Location: Seminar Room; Electronic Research Center

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چهارشنبه ۳ شهریور ۱۳۸۹ -

Mahmoud Vaghefinejad

Department of Electrical Engineering MA Dissertation Defense Meeting Transmission loss allocation through power flow tracing considering cross effects of active and reactive power and unusual power flow Abstract Transmission loss allocation is one of the important issues in deregulated system. Transmission loss have to be allocated in a fair and convincing manner between all participants of market. Based on different approaches, several methods have been introduced for transmission loss allocation in literatures. In this work a new tracing method based on proportional sharing principle presents, for the determination of generator’s and load’s share in transmission loss. The proposed method needs no exhaustive search or prior determination of feed paths and requires no matrix inversion or additional nodes for representing losses. In this method active and reactive power trace simultaneously, not separately as most of the available methods and takes into consideration the cross effects of active and reactive power on reactive and active power loss. Also the method deals with unusual power flow such as lines with reactive power infeed from both ends and lines with different flow directions of active and reactive power. Student: Mahmoud Vaghefinejad Supervisor: Dr. Heydar Ali Shayanfar Jury: Dr. Shahram Jadid, Dr. Mohsen Kalantar, Dr. Masoud Aliakbar Golkar Time of Defense: 10 AM Date of Defense: 1389.6.15 Location: Seminar Hall of Faculty of Electrical

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سه شنبه ۲۲ تیر ۱۳۸۹ -

Ahmad Ghanaatian-Jahromi

Iran University of Science and Technology School of Electrical Engineering MS Thesis Defense 269 Design of A UWB Pulse Generator Abstract In this thesis, a new optimal waveform for Ultra-wideband (UWB) radio is proposed. This new waveform is extracted through mathematical analysis for achieving high spectral utilization under the restrictions imposed by the U.S. Federal Communications Commission (FCC) spectral masks. Exploiting Inverse Fourier Transform (IFT) of FCC mask, the required analog signals are extracted through robust calculations. Normalized effective signal power (NESP) of the proposed method is calculated to be 95.27% which shows better efficiency compared to the other methods in the literature. In addition, the method is employed to achieve an optimal pulse for the main UWB band (3.1 GHz to 10.6 GHz) and a block diagram for analog realization is proposed. Simulation results verified that the presented technique is very promising and has better performance compared to the other pulses in literature. Finally a circuit level realization of the designed pulse is proposed to complete the work while the simulation results show high spectral efficiency and confirm the advantage of using this pulse in UWB transmitters. . By: Ahmad Ghanaatian-Jahromi Supervisor: Dr. Adib Abrishamifar Co Supervisor: Dr. Ali Medi Referees: Dr. Sattar Mirzakoochaki, Dr. Hossein Shamsi July 17, 2010 Time: 10 School of Electrical Engineering, Seminar Room

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سه شنبه ۲۲ تیر ۱۳۸۹ -

Khosro Khandani

Iran University of Science and Technology Electrical Engineering Department Master of Science Thesis Defense Session 269 Design of Disturbance Rejection 2-DOF Fractional-Oder PID Controllers for Time Delay Systems Abstract Fractional-order PID controllers in which the order of integrating and derivative operators are of non-integer order, have widely attracted attention in recent years. Since there are two extra parameters in these controllers, they can be adjusted more precisely to achieve the desired performance. However, finding these parameters is a more complicated task. In addition stability analysis of fractional systems differs from existing methods for stability analysis of integer order systems. In this project fractional PID controllers in a 2-Degree-Of-Freedom structure have been applied to time delay systems. Owing to the dead time in time delay systems, they need a compensator which can remove undesirable effects of the dead time so that an appropriate response can be achieved. The purpose is to obtain the desired response in presence of disturbance. In order to obtain the optimal parameters of the controller particle swarm optimization technique and genetic algorithm have been used. By assuming interval uncertainty for the parameters of the plant, robust stability of the system with the optimal controller designed by particle swarm optimization and genetic algorithm, has been analyzed. This controller cannot be applied to the systems with long time delays. To solve this problem a filter with a gain higher than the gain of the plant is added to the system. By adding this dominant gain filter, non-minimum-phase effects of the dead time are removed. Selecting a fractional order filter rather than an integer order one, phase shift effect which may appear in phase behavior of the system by using integer order filters is reduced. This compensator also has an acceptable performance in disturbance rejection. Student: Khosro Khandani Supervisor: Dr. Ali Akbar Jalali Advisor: Dr. Mohammad Reza Jahed Motlagh Examiners: Dr. Hooman Sajjadian; Dr. Mohammad Saleh Tavazoei Date: 21 July, 2010 Time: 10 A.M. Location: Seminar Hall of Electrical Engineering Department

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سه شنبه ۲۲ تیر ۱۳۸۹ -

mehdi arabghobadi

School of Electrical Engineering Thesis defense meeting of the Masters 269 Simulation of sensorless vector control of induction motor using MRAS in low speed region Abstract In this Thesis, a method is presented for compensating the inverter output voltage, which does not depend to inverter switches specifications. In this method, the required pulse wide for compensating output voltage is obtained by use of sixth harmonic feedback of stator current in synchronous reference frame. In this way, the produced distortion in output voltage which is created as a result of the dead time effect and the zero current clamping, at low frequency and in light load, is compensated. This method is applied in indirect vector control induction motor. To include dead time between one leg related switches, a method is presented to prevent short circuit in DC link, which doesn’t lead to difference creation between reference voltage and inverter output voltage. Combination of this method with inverter output compensation by use of sixth harmonic feedback is used for inverter output voltage compensation in induction motor sensor less vector control. In sensor less vector control for rotor speed estimation, at first, reference frame on the base of rotor flow estimation has been used. The model which has used as a reference is such that rotor resistance variation and DC offset trace is compensated in it. With this combination speed control at low frequency has made possible. Simulation results show that speed estimation method is sensitive to noise. To solve this problem, reference model on the base of stator current estimation is used. A method is presented to estimate stator current which does not depend to stator resistance and current estimation does not require derivative. Thus, the presented method is stable to stator resistance variation, DC offset and noise effect and at low speed is applicable. Student: mehdi arabghobadi Supervisor : Dr. hossyn heydari Arbitration Committee : Dr. abas sholay; Dr. davod arabkhabori; Dr.javad shokrolahi moghani Date of Defense: Monday 28/4/89 Time: 10 Location: Seminar Room, School of Electrical Engineering

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سه شنبه ۲۲ تیر ۱۳۸۹ -

Maryam Najmafshar

Iran University of Science and Technology School of Electrical Engineering Msc Thesis Oral Defence Notice 269 Performance Analysis of OFDM-based Multihop Wireless Systems with Adaptive Modulation in Fading Channels Abstract As information and communication technology develops, the demand for ubiquitous communication networks with fast and high quality grows. Next wireless networks, are so dynamic in terms of their performance. One of the most fundamental characteristics of wireless channels is fading. Since the current view on multipath fading recognizes that random fading increases the number of degrees of freedom available for communication, these degrees of freedom and also broadcasting nature of wireless signals need to be exploited in the emerging standards. By using multihop transmission besides these characteristics we can enhance the performance of wireless connection without any increase in device complexity (unlike MIMO technology). In this research, we provide a performance analysis of a two-hop OFDM based network with fixed relays under MQAM modulation, in terms of average throughput and probability of outage. Although using relays has the benefits of multihop systems, this increases the complexity of analysis because of an increase in the number of paths which can carry a symbol. Referring to the analytical calculations and simulation results we have shown that using selective OFDMA relaying scheme makes more improvement in system performance which is an increase in throughput for a boundary user up to 60 percent in comparison with single hop system. Moreover, this method leads to a dramatically reduce in probability of outage in all reviewed cases. For example we need more than 20 dB less power in transmitter by using selective OFDMA relaying method to achieve outage probability equal to . Student: Maryam Najmafshar Supervisor: Dr. Vahid Tabataba Vakili Referees: Dr. Seyed Mohamad Razavizadeh; Dr. Bahman Abolhassani; Dr. Ali Asghar Beheshti Shirazi Date: Saturday 89/4/26 Time: 17 PM Location: Room 205 Electrical Engineering department

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سه شنبه ۲۲ تیر ۱۳۸۹ -

Maryam Najmafshar

Iran University of Science and Technology School of Electrical Engineering Msc Thesis Oral Defence Notice 269 Performance Analysis of OFDM-based Multihop Wireless Systems with Adaptive Modulation in Fading Channels Abstract As information and communication technology develops, the demand for ubiquitous communication networks with fast and high quality grows. Next wireless networks, are so dynamic in terms of their performance. One of the most fundamental characteristics of wireless channels is fading. Since the current view on multipath fading recognizes that random fading increases the number of degrees of freedom available for communication, these degrees of freedom and also broadcasting nature of wireless signals need to be exploited in the emerging standards. By using multihop transmission besides these characteristics we can enhance the performance of wireless connection without any increase in device complexity (unlike MIMO technology). In this research, we provide a performance analysis of a two-hop OFDM based network with fixed relays under MQAM modulation, in terms of average throughput and probability of outage. Although using relays has the benefits of multihop systems, this increases the complexity of analysis because of an increase in the number of paths which can carry a symbol. Referring to the analytical calculations and simulation results we have shown that using selective OFDMA relaying scheme makes more improvement in system performance which is an increase in throughput for a boundary user up to 60 percent in comparison with single hop system. Moreover, this method leads to a dramatically reduce in probability of outage in all reviewed cases. For example we need more than 20 dB less power in transmitter by using selective OFDMA relaying method to achieve outage probability equal to . Student: Maryam Najmafshar Supervisor: Dr. Vahid Tabataba Vakili Referees: Dr. Seyed Mohamad Razavizadeh; Dr. Bahman Abolhassani; Dr. Ali Asghar Beheshti Shirazi Date: Saturday 89/4/26 Time: 17 PM Location: Room 205 Electrical Engineering department

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Ali Ghaffari nejad

School of Electrical Enginnering Master of Science Dissertation Present 269 Medical Image Registration by Mutual information abstract Mutual information (MI) criterion as a similarity measure is a concept assessing the likeness of two images or probability distribution. Increasing the similarity between to images, by any means, would help us to estimate the total structure and behavior of an image, in case we have the other image in hand. Registration of medical images is one of the common issues in current medical practices, which is developing very rapidly in both new findings and new areas of research. Alignment of functional images, which mostly show soft organs, with structural images, that basically depicts hard parts of the body, is the main objective of the medical image registration. Despite the intrinsic difference between functional and structural images of the same scene, there are still some similarities in image intensity values of the same organ in both images. Similarity between corresponding tissues in two images can be increased by applying a transform to one image. Measuring the amount of similarity among two images is upon to MI. Therefore, we expect that the best alignment between images occur when the likeness of images is the maximum amount according to MI criterion. In this thesis we present an improved algorithm for medical image registration based on MI criterion, along with a new configuration for normalized form of MI that has smoother variations which makes it possible for heuristic algorithms to play a role in registration algorithm. Keywords : Image registration, Mutual information, Entropy, Similarity measure Student : Ali Ghaffari nejad Supervisor : Dr. Ahmad Ayatollahi Dissertation Committee : Dr. H.Behnam , Dr.M. Pooyan Date: 22/4/89 Time: 16 Place: School of Electrical Eng. Seminar Room

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Mohammad Nasser Saadatzi

Iran University of Science and Technology Electrical Engineering Department Master of Science Thesis Defense 269 Robust Multivariable Controller for Linear and Angular Velocities of Electrically-Powered Wheelchair Abstract Robust multivariable controller for linear and angular velocities of electrically-powered wheelchair (EPW) is presented. Because of inaccessibility to a real EPW, at first, a virtual one is extended using MATLAB and CATIA in order to perform experiments and verification of the controller. The virtual EPW (VEPW) takes into account complicated motion of castors, resistant forces exerted to wheels, nonlinear behavior of gearboxes, core saturation of electric motors, etc. Uncertain weight and uncertain center of gravity (COG) of occupant are studied precisely. By combination of geometric features of EPW and electric DC motors dynamics, dynamic equations of system are acquired in the form of a 2-input-2-output transfer function matrix. An additive unstructured perturbation matrix is calculated by variation of occupant weight within the range of 40 kg. to 120 kg. and variation of COG in the range of seat. In order to achieve performance objectives and robust stability, two controllers are designed using characteristic loci method and two-degree-of-freedom structure including a disturbance observer and proportional-integral controller. The designed controllers, finally, are implemented on the VEPW and their performances are studied for whole uncertainty range of occupant weight and COG. Student: Mohammad Nasser Saadatzi Supervisor: Dr. Javad Poshtan Advisor: Dr. Alireza Mohammadshahri Referees: Dr. Behzad Asayee, Dr. Aliakbar Jalali Defense Date: July 11th, 2010 Defense Place: Seminar room

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Rahim Khorsandi Gavgani

Iran University of Science and Technology Electrical Engineering Department Defense meeting of M.SC Thesis Determination of Equivalent Salt Deposit Density on High Voltage Insulators by Artificial Neural Network Abstract Electric power transmission network are near different source of pollution so the insulators surface leakage current increases and probability of flashover can increased. During the past years several criteria to assess contamination has been introduced, one of the most common is ESDD . There are Different methods to determine ESDD . Some of them include regression - based method to find mathematical relationships between different parameters which can important effect on pollution . These methods some times haven’t any answer, because during the mathematical operations to calculate the amount of ESDD, in some cases it is necessary to obtain the inverse matrix but matrix’s Determinant is zero. The Other methods for determination of ESDD use sampling measurement of actual contamination there for they are time consuming and expensive . In order to solve the mentioned problems, using a smart method is appropriate because these methods typically have suitable speed and accuracy . Artificial neural network has been selected so we don’t need obtaining of mathematical relationship between the parameters. In this thesis, using a MLP neural network structure and change the number of hidden layer neurons ESDD levels with appropriate accuracy is obtained. Simulations results show that the number of layers of neural network have important influence on accuracy of ESDD prediction. Amount of pollution divided to four group low, medium, high and very high. Artificial neural network can online predict the ESDD of polluted insulator. During prediction of ESDD by ANN, some parameters such as temperature, wind velocity, insulator dimension and rain have more influence. Normalization of data between -0.9 to 0.9 causes that effect of all data calculated in prediction so accuracy of obtained ESDD value is better than references. Student: Rahim Khorsandi Gavgani Supervisor: Dr. Ahmad Gholami Dr.Kalantar,Dr.Heydari,Dr.Shahvarani Defence Date:7 july 2010 Time:10:12 Location:Electrical Engineering Department

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سه شنبه ۱۵ تیر ۱۳۸۹ -

BEHROOZ SHEYKHLOEI

Iran University of Science and Technology Electrical Engineering Department Defense meeting of M.SC Thesis Fault Location On Overhead Lines Based On Traveling Waves And Wavelet Transform Abstract: The main purpose of this research is introducing an effective technique for determination of fault locationof overhead lines. The proposed method is based on the frequency and time decomposition of voltage signals that traveling waves theory and wavelet transform are used. Application of CVT for providing data samples of transient voltages is another subject that is mentioned. Two significant methods wich have been broadly classified are: 1)frequency approach has very complicated transmission line equation, and Selection of logic answers are very difficult for them. 2) High frequency Traveling wave approach) has very rapid responses, with enough accuracy, though it has inherent problems. In this research EMTP/ATP for overhead line simulation and MATLAB capability for signal analyses are used. At the end of the thesis a useful algorithm for fault location is described and defined. Comparison of estimated results of this algorithm, different types and resistance faults, and real locations is accurate and acceptable. Reducing errors and costs because of measurement devices reduction, is another advantage of this method. By: BEHROOZ SHEYKHLOEI Adviser: AHMAD,GHOLAMI Ph.D. Judgment members :Dr.Gharepetyian- Dr. Shahrtash -Ms. Kazemi Defense Date: Monday 5 July 2010 Tim: 8.30-10.30 Location :Electrical Engineering Department

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Morteza Daneshkar Allam

Department of Electrical Engineering Defense Notification of Master of Science thesis 269 A Combine Method to Solving Permutation Ambiguity for Blind Source Separation in Convolutive Mixture in Frequency Domain Abstract: Blind Source Separation is an attractive signal processing issue due to many desirable application. Using this approach one can separate observed signals from their mixture. Many methods exist for solving the BSS problem that separation of signals in time–frequency plane is one of them. In all time-frequency methods, using a time-frequency transformation observed signals are first transformed form time to time-frequency plane. After separating the signals, each signal can then be turned back to time domain. Using this method to separate, causing two permutation and scaling ambiguity. The scaling ambiguity is solved problem but permutation ambiguity is open problem. Since many ways to solve this problem is presented, but none of these methods so far have been unable to fully solve this problem. We proposed in this thesis presents a new combination method is a combination of initializing and Direction Of Arrival methods for solving permutation ambiguity. In this way our entire frequency spectrum divided into sections and perform initializing and DOA estimation in each sector for solving permutation ambiguity. This reduces the propagation error in the Initializing method and speed up the convergence of the ICA algorithm. Student: Morteza Daneshkar Allam Supervisor: Dr. Mohammad Hoseain Kahaei Referees: Dr.Tabatabavakili , Dr.Abolhasani, Dr. ardebilipour

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Ahmad Mirzaei

School of Electrical Enginnering Master of Science Dissertation Present 269 Detection of Seizures and Epilepsy using Non-Linear and Chaotic Methods abstract Epilepsy is a common neurological disorder, offering 1% of people around the world. No certain cure has yet been found for this brain problem. Nearly 75% of all patients are brought to a normal state with anti epilepsy medicines or by neurosurgery. For the last decades many studies have been conducted in order to determine the onset of an epilepsy seizure. EEG signals are useful means for this purpose. EEG signals are recorded periods of brain activities in a definite long duration. Traditional methods of diagnosis based on Trial and error for their time inefficiency have become a boring procedure while a high rate of failure. Obviously such error and miss diagnosis have adverse effects of healing procedure. This work is a simulation study using hybrid methods of wavelet-entropy to detect the onset of a seizure. Entropy parameters are chaotic which measures the amount of randomness in EEG signals. Student : Ahmad Mirzaei Supervisor : Dr. Ahmad Ayatollahi Cosupervisor : Dr. A. M. Nasrabadi Dissertation Committee : Dr. A.Sadr , Dr.M. Pooyan Date: 22/4/89 Time: 16 Place: School of Electrical Eng. Seminar Room

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Karim nasiri moghaddam

Iran University of Science and Technology Electrical Engineering Department Defense meeting of M.SC Thesis Recognazing of Sag voltage in 20 kV sample station feeders in Distribution System Abstract : Power Quality has many different definitions. For Electrical company power quality means non existence of interruption on end and present the statistic in base of there ideas. There are some different reasons for power Quality investigation in field of voltage sag. Sensitive loads in some consumption is a reason for this investigation. From view point of consumption power quality means another thing and has a great importance. Main goal of this thesis is estimating of voltage by modeling and simulation of sample network and applying difference fault and inspection network status due to fault time. Verifying Voltage sag in 20 kv feeders and his effect on other feeders and so finding the methods for solving this problems .there for needing of Verifying of distortion and informing the customer at the being of a industrial project is essential .for opposition this distortion the necessary actions in customers section is a cheaper method as prevention . By: Karim nasiri moghaddam Adviser: Alireza jalilian, Ph.D. Judgment members :Dr.sholaie - Dr. haidari -Dr. ghandehari Defense Date: Monday 13 July 2010 Tim: 10-12 Location :Electrical Engineering Department

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سه شنبه ۱۵ تیر ۱۳۸۹ -

Ehsan Darabi

Electrical Engineering Faculty M.Sc. Oral Defense Notice 269 Design, construction and uncertainty analysis of a 3-Axis Flux-Gate magnetometer Abstract: To provide a sensor for attitude determination system of a satellite, the idea came up to construct an instrument able to measure the earth's approximately constant magnetic field. There are a few procedures to get along with the matter among which the "Flux-Gate" seems most appropriate for the situation. Based on a specific viewpoint that is offered throughout the current thesis, a Flux-Gate magnetometer is divided to 3 separate issues; "Excitation Circuit", "Sensitive Part or Sensor Head" and "Output Electronic Circuit". Sensitive part composing two sets of winding known as excitation and pick-up coils beside a ferromagnetic core is supposed as our Flux-Gate's heart. Excitation circuit provides a periodic current through excitation winding and causes a regular and distinct change to core's magnetic state and also large enough to magnetically saturate the core. When saturation occurs, core's reluctance suddenly collapses and permits the external flux inside the core. Thus a periodic voltage typed signal turns up at Pick-Up coil. The finishing task is to process the picked up voltage so that both magnitude and direction of the DC magnetic field nearby the sensor head exactly measured. Also there are a few sources of uncertainty inside those three units that may cause errors to extracted DC voltage. They are briefly described in the text. By: Ehsan Darabi Supervisor: Dr. Husain Bolandi Advisor: Dr. Javad Poshtan Jury: Dr. Ali Reza Mohammad Shahri; Dr. Mehrzad Nasirian Presentation time and place: 5:00 P.M., Sunday, July 18th, 2010 Seminar Hall, Electrical engineering faculty

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سه شنبه ۸ تیر ۱۳۸۹ -

Mehdi Hamidkhani

Iran University of Science and Technology Electrical Engineering Department Oral defence of Msc thesis 269 Wide-Band Microstrip Patch Antennas Using Parasitic Elements and Defected Ground Structures on Different Substrates Today with regard to the needing for miniaturized communication block have been raised small antennas applications. Microstrip patch antennas are suitable candidates for such applications. But size of these antennas is large in low frequencies. Several methods have been proposed for the miniaturization of antennas in some references, which have some shortcomings, such as reduction of impedance band widths. Realization of both good, impedance bandwidth and small antenna size is difficult and are almost contradictory. That is, improvement of one, deteriorates the other. Moreover, reduction of antenna size caused to perturbation in radiation pattern and reduction of gain and radiation efficiency. In this work, present some of novel methods for reduction of antenna size and increasing bandwidth; as minimum perturbation in radiation pattern, efficiency and gain of antenna occur . In one of methods, a square patch with mitred corners on low dielectric substrate together with some of smaller square parasitic patches on a substrate with high permittivities is introduced, which tends to reduce the antenna size, generate circular polarization, and increase the frequency bandwidth. In another method, for the increase of antenna bandwidths. We use appropriate feeding systems, impedance matching techniques and increase of substrate thickness. These techniques have been use in such a way to produce antenna miniaturization. Then production structure integrated using SIW technique. In third method, design a miniaturized multiband microstrips antennas with helical slot patterns on patches. Then, a novel microstrip notch filter with slotted patch resonator is introduced which may be used for rejection of spurious signal frequencies and prevention of wave interference (for example rejection of the WLAN frequency bands from the UWB communication systems). Finally, survey influences body on UWB antenna and introduce a method for reduction of influences Body on radiation antenna. By: Mehdi Hamidkhani Supervisor: Dr. Oraizi Refers: Dr.Komjani, Dr.Vajed samiei and Dr.Rashed mohassel defence date: 2010/07/06 Time: 17:00

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سه شنبه ۸ تیر ۱۳۸۹ -

Mohsen Parsa

Iran University of Science and Technology Electrical Engineering Department Msc Defense Session 269 Biped Robot Motion Control Through Disturbance Observer Abstract Research on the legged robots has been started since 1970. Because of the intrinsic instability and walking stability constraint, legged robot motion control, especially in bipeds, is more complicated than wheeled robots or manipulators. However, tolerating these difficulties, legged robots have more moving abilities than wheeled robots encountering uneven and discontinuous surfaces. In this thesis, nonlinear model predictive control (NMPC) of a five links biped robot is considered. Gait generation and motion control phases are done by the NMPC simultaneously and real-time. Based on this idea, biped control is not based on trajectory following and is trajectory free. Letting the NMPC to decide about both the walking pattern and control of the biped has advantages such as reaching to more optimal walking while considering the actuator and physical constraints of the biped. But the NMPC is a model based control which suffers from uncertainty and disturbances. In order to robust the controller, nonlinear disturbance observer is applied to the control loop. Thus, having the NMPC trajectory free advantages, the controller has sufficient robustness to unavoidable uncertainty and disturbances. In contrast to the NMPC advantages, computation time of it is a big deal which restricts the NMPC efficiency. In order to reduce the computation time, the main NMPC responsibilities are divided to three smaller NMPCs which are solved in series. Although these NMPCs are solved in series, the computation time is reduced. Student: Mohsen Parsa Supervisor: Dr. Farrokhi Advisor: Dr. Sajjadian Refrees: Dr. Shahri; Dr. Moosavian Defense Time: Jun 29 2010 at 10:00 Location: Seminar Room

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سه شنبه ۸ تیر ۱۳۸۹ -

Mohammad Hoseyn Akbarpour

Iran University of Science and Technology Electrical Engineering Department Defense meeting of M.SC Thesis The Simulation Impact of Phase Shifting Transformer on Real Network For Preventing of Building New Transmission Line Abstract : Development of transmission systems is a necessity in power network. One of the requirements of this development is making new trans miss lines, but building of new lines is expensive and time consuming. Because of capability of phase shifting transformers in voltage phase angle change, there upon their capability for controlling active power flow, one of the applications of P.S.T, this idea purposed that instead of building of new transmission lines, to be installed in network a P.S.T. There for two discrete sample network 14 bus IEEE standard, and 230 KV & 400 KV Azarbaijan regional electric company planned network for the year 1393, are selected to accomplish selective idea on them, and to check if they are practical. Each candidate line eliminate in these networks and step by step a P.S.T is installed after simulation network in Digsilent. In this network every line is omitted one by one and one P.S.T is installed over each line that can be connected to bus's in each two sides, sequence and multiple load flow study runs equal numbers of steps that active power loading on P.S.T for a allowable range and in two sides, power entrance, exiting, so that it can use quantities of busbar voltage and power flow across lines. assessment two index "Voltage Profile" and "Line Loading" calculation with along network power loss index (as an other index) after normalization and admixture in one final index that is named: "composition assessment index" its accrete possibility technical witting for P.S.T's suitable location instead of introduction of a new line. Afterwards for suitable cases, P.S.T's rated power arrow with contingency study and range of voltage phase variation arrows by an number of tap chenger's step. Finally out put analysis shows that after installing a P.S.T in nerwork and Preventing some new lines results in affecting on P.S.T's ability for permanent improvement lines loading and probable improvement voltage profile and probable reduction for network's loss. By: Mohammad Hoseyn Akbarpour Adviser: MOHSEN KALANTAR, Ph.D. SADEGH JAMALI, Ph.D. Judgment members :Dr.Gharepetyian- Dr. Shayanfar -Dr. Jaliliyan Defense Date: Monday 5 July 2010 Tim: 9-11 Location :Electrical Engineering Department

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سه شنبه ۸ تیر ۱۳۸۹ -

shahram hedayati

Iran University of Science and Technology Electrical Engineering Department Oral defence of Msc thesis 269 Analysis, design and optimization of novel fractal radiator and fractile array Fractal geometries are widely used in radiating systems and even microwave devices to benefit from their interesting properties. Application of fractal geometries to the design of antennas leads to their miniaturization and multi-band characteristics. Since the generation of fractal configurations have an iterative procedure, then they can achieve long linear dimensions and high surface areas in a limited volume. However, in this project we present the novel structures and application of those in the micro strip antenna and then we compare the miniaturization performance of proposed fractals antenna with that of other fractals. First proposed structure in this thesis is Giusepe Peano fractal geometry, which realizes its miniaturization while maintaining its gain and bandwidth. These novel fractal geometries used for different micro strip antennas and we survey characteristics of these . In another section of this thesis the combined fractal proposed, that these structures are common fractal that combined together for approach higher degree of freedom that further miniaturization of antenna may be achieved. In another section of this project we proposed the novel geometries for monopole fractal antennas, in this section we introduced Lebesgue fractal geometries and use of this for design of multi-band antennas with circular polarization in all of the bands. In final section, we use wavelet basis functions in the method of moment and present novel algorithm for selection dominant basis functions and then we used MLMDA method in method of moment, required storage memory and cpu time reduced with respect to the common method of moment. By: shahram hedayati Supervisor: Dr. Oraizi Refers: Dr.Hojjat Kashani,Dr.komjani and Dr.hakak defence date:2010-07-06 Time: 15 Place:

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سه شنبه ۸ تیر ۱۳۸۹ -

Arash khodadadi

School of Electrical Engineering Oral Defence of Master Thesis 269 Parameter Identification in Nonlinear Regression Using Bayesian Filters This thesis is devoted to three main topics: state estimation in nonlinear systems, nonlinear function approximation and optimal control of nonlinear systems with uncertain dynamics. The common theme among all of these is the Bayesian state estimation in nonlinear dynamic systems. In this research, first two methods for Bayesian state estimation are compared: the Unscented Kalman filter which is a popular method in nonlinear state estimation and the Cubature Kalman Filter which is one of the most recently developed filters in nonlinear Bayesian filters literature. The performance of these filters is investigated using both simulation and theoretical analysis. The results show that the Cubature Kalman filter can achieve the same performance as the celebrated Unscented Kalman filter but with less complexity. Next, it is shown that how a nonlinear function approximation problem can be seen as the problem of state estimation in a nonlinear dynamic systems. Then the method of training neural network using Bayesian filters is explained and after that, for the first time, the Cubature Kalman filter is employed to train a radial basis network to solve two problems: first, approximation of a nonlinear function with two inputs and second prediction of a chaotic time series. The aim of the rest of this thesis is to develop a stable optimal controller for nonlinear systems with uncertain dynamics. The reinforcement learning (RL) provides the necessary theoretical basis for designing optimal controller for nonlinear systems with unknown dynamics. But, one of the main issues the RL-based controllers suffer from is the lack of stability guarantee. In this thesis, a robust controller is employed to ensure the stability of the closed-loop system. This control strategy restricts the possible action space of the RL agent such that the whole system will remain stable. To use this control strategy in continuous state and action spaces, the value of each action in each state is approximated using Bayesian trained neural networks. Performance of the developed controller is investigated in comparison to a constant gain controller with some simulations. At the end of this thesis, one of the previous solutions to the exploration-exploitation dilemma in RL is extended to the continuous state environment. This extension is done in regard to the Bayesian filter based RL framework. Name: Arash khodadadi Supervisor: Dr.Javad Poshtan Advisor: Dr. Babak Nadjar Araabi Referees: Dr. Mohammad Farokhi, Dr. Hamid Khaloozadeh Date: July 4, 2010 Time:17

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سه شنبه ۸ تیر ۱۳۸۹ -

Shaho Ghanei

Iran University of Science and Technology Electrical Engineering Department 269 Session of defence for fulfillment of the degree of Master of Science Detection of rotor eccentricity fault in BLDC motors operating under Nonstationary conditions Abstract: Diagnosis and Condition monitoring of BLDC motors due to their rapidly growing applications, especially in harsh and critical ones, have a special importance. Early detection of faults could allow preventive maintenance to be performed and provide sufficient time for controllers to shut down the affected process. Rotor is one of the major sources of faults in motors. On-time detection of rotor eccentricity fault in BLDC motors operating in Nonstationary conditions by using modified Motor Current Signature Analysis method (MCSA) is the main emphasis of this research. In order to simulate the transient electrical and mechanical parameters of the healthy and faulty motor, the two dimensional Finite Element Method (FEM) is used. Since in Nonstationary conditions motor current signal is Nonstationary, the ordinary Motor Current Signature Analysis method can not be used. In this research a novel method is proposed. Current of the motor which is operating in Nonstationary condition, will be sampled based on rotor angle instead of time. Then order analysis is implied on the sampled current signal of healthy and eccentric rotor motor. Finally by comparing the order analysis of these two signals, feature of the rotor eccentricity fault will be extracted and the detection scheme will be completed. Student: Shaho Ghanei Supervising professor: Dr A.R. Rahmati Outside defence committee member: Dr Sh. Kaboli Defence committee members: Dr S. Mirzakouchaki ; Dr A. Abrishamifar Date of the defence : Monday, June 28, 201 Time: 8 AM Place: Seminar room, Electrical Engineering Building No. 1

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سه شنبه ۸ تیر ۱۳۸۹ -

BEHROOZ SHEYKHLOEI

Iran University of Science and Technology Electrical Engineering Department Defense meeting of M.SC Thesis Fault Location On Overhead Lines Based On Traveling Waves And Wavelet Transform Abstract : The main purpose of this research is introducing an effective technique for determination of fault location of overhead lines. The proposed method is based on the frequency and time decomposition of voltage signals that traveling waves theory and wavelet transform are used. Application of CVT for providing data samples of transient voltages is another subject that is mentioned. Two significant methods wich have been broadly classified are: 1)frequency approach has very complicated transmission line equation, and Selection of logic answers are very difficult for them. 2) High frequency Traveling wave approach) has very rapid responses, with enough accuracy, though it has inherent problems. In this research EMTP/ATP for overhead line simulation and MATLAB capability for signal analyses are used. At the end of the thesis a useful algorithm for fault location is described and defined. Comparison of estimated results of this algorithm, different types and resistance faults, and real locations is accurate and acceptable. Reducing errors and costs because of measurement devices reduction, is another advantage of this method. By: BEHROOZ SHEYKHLOEI Adviser: AHMAD,GHOLAMI Ph.D. Judgment members :Dr.Gharepetyian- Dr. Shahrtash -Ms. Kazemi Defense Date: Monday 5 July 2010 Tim: 8.30-10.30 Location :Electrical Engineering Department

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دوشنبه ۳۱ خرداد ۱۳۸۹ -

Asiye Aghazade

Department of Electrical Engineering MA Dissertation Defense Meeting Coordinated Design among PSS and TCSC(STATCOM) for Damping Oscillations in Power System Abstract For increasing the stability of power system oscillations the initiation of a supplementary exciting control is an economical, effective and simple method. In multi-machine systems only use of traditional PSS don’t provide enough damping for inter-area oscillations. In power systems FACTS devices in addition to basic control duties for example voltage regulation and injection of reactive power can damp power system oscillations. In any case local control without coordination of FACTS devices and PSS, may lead to unstable interactions so design of coordinated parameters of PSS and FACTS device stabilizers is an important subject in power engineering which this thesis propose two coordination methods between PSS and two FACTS devices (TCSC and STATCOM). In these methods reaching to maximum damping of oscillations in test system with reducing interaction between power system stabilizer and power oscillation damping. Student: Asiye Aghazade Supervisor: M r. Ahad Kazemi Jury: Dr. Alireza Jalilian, Dr. Mohsen Kalantar, Dr. Seyyed Hossein Hosseiniyan Time of Defense: 9 AM Date of Defense: 1389.4.7 Location: Seminar Hall of Faculty of Electrical

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دوشنبه ۳۱ خرداد ۱۳۸۹ -

Mohammadjavad Jannati

Electrical Engineering Department Final Defense Session of MSc Thesis 269 A New Method to Improve Performance of Cooperative Communication in Underwater Acoustic Systems Abstract: In this thesis cooperative communication approach in underwater acoustic systems is studied. For this purpose, firstly, features of acoustic waves and sound are studied. After that cooperative communication in radio channels is studied. Then work is extended by working on underwater acoustic channel and its features. In this thesis a new method to improve performance of underwater acoustic channel called “adaptive frequency controlled transmission” is proposed. Then cooperative communication in underwater acoustic channels is simulated. “Amplify and forward” and “decode and forward” schemes are adapted and applied to underwater acoustic channel. After that, combination of cooperative approaches and adaptive frequency controlled method is applied to underwater acoustic channel. In continuation, work on active nodes and rayleigh fading in underwater acoustic channel is begun by using alamouti coding and transmission scheme. Finally combination of alamouti approach and adaptive frequency controlled scheme applied to underwater acoustic communication channel and made proper performance improvement on it. Simulations of this thesis shows that approach of cooperative communication can make proper improvement on bit error rate performance of underwater acoustic communication in underwater channels. Student: Mohammadjavad Jannati Supervisor: Dr. Vahid Tabatabavakili Referees: Dr. Kahaei; Dr. Abolhasani; Dr. Mohamedpoor Date: 21th of June 2010 by 3 PM Location: Class 203 of electrical engineering department

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دوشنبه ۳۱ خرداد ۱۳۸۹ -

Mohsen Hejazi

School of Electrical Engineering Final Defense session of The MSc Thesis A New Method for Cooperative Spectrum Sensing in Cognitive Radio Networks over Correlated Channels Abstract Monitoring and detecting the presence of primary users and unoccupied bands of frequency spectrum (spectrum holes) is the basic functionality of a cognitive radio network. A variety of methods has been proposed to provide efficient and robust spectrum sensing. However, shadowing and fading effects degrade the performance of these methods significantly. In this thesis, we exploit multi-antenna and cooperative spectrum sensing to lower effects of fading and shadowing. In addition, we consider both spatial-correlation among antennas and spatial-correlation among users, as it appears in practical applications, in our performance evaluation. Generally, the well-known energy detector is used for spectrum sensing. Energy detector has a low complexity but suffers from uncertainty in noise statistics and its performance in low SNR values is unsatisfactory. To overcome these problems of energy detectors, we employ cyclostationarity based spectrum sensing. In our theoretical analysis, we drive a closed-form equation for the false alarm probability of cyclostationarity-based multi-antenna cooperative spectrum sensing over different channels as well as a closed-form equation for the detection probability of this method over AWGN channels. To implement an optimal fusion rule for cooperative spectrum sensing, the false alarm probability and the detection probability of each secondary user (SU) must be known at the secondary base station. However, these statistics are usually unknown or may vary with time. In this thesis, we proposed an adaptive spectrum sensing method which is based on estimation of the probabilities of SUs and thus, there is no need for any knowledge about SUs at the base station. Moreover, we modified this method for the case of mobile users. Simulation results show that our new method can track changes closely and the sensing performance is near optimal method. Student: Mohsen Hejazi Supervisor: Dr. Abolhassani Referees: Dr. Tabataba-vakili; Dr. Beheshti; Dr. Nasiri. Defense date: 20th of June by 3 PM Auditorium of Electrical Engineering Department

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شنبه ۲۹ خرداد ۱۳۸۹ -

Mahdi Ebrahimzadeh

Department of Electrical Engineering Master of Sciences Degree Defense Design of a Current Controlled Oscillator, with Improved Features, Emphasizing in Phase Noise Reduction Abstract A low voltage and high quality factor active inductor is designed. By biasing bulk terminals to a positive voltage we reduce the supply voltage of design. Adding a feedback resistor made the active inductor to have very high quality factor and an independent inductance and quality factor tuning. The active inductor was simulated with ADS simulator and TSMC RF 0.18 µm CMOS designkit. The active inductor has a quality factor equal to 12370 and supply voltage of 0.8 V and 1.9 mW power dissipation. Moreover, A method to decrease the phase noise of the sinusoidal oscillators is implemented. The method is based on using a dynamic transistor biasing in a typical oscillator topology. This method uses the oscillator impulse sensitivity function (ISF) shaping to reduce the sensitivity of the oscillator to the transistor noise and as a result reducing the oscillator phase noise. This method is used to decrease the phase noise of an active inductor based LC oscillator. An oscillator based on the method shows a phase noise of -101 dBc/Hz at 1MHz offset frequency, thereby showing about 5.5 dB phase noise decreasing in comparison with the reference constant bias topology. This result is obtained from the simulation based on TSMC RF 0.18µm CMOS technology in ADS simulator. Student : Mahdi Ebrahimzadeh Advisor : Dr Seyed Javad Azhari Jury: Dr Ayatollahi, Dr Mirzakouchaki and Dr Shamsi Date : Sunday 1389/4/6 at 10 AM Place : Seminar Saloon, Electronic Research Center

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سه شنبه ۲۵ خرداد ۱۳۸۹ -

Khadijeh Nakhaei

Iran University of Science and Technology School of Electrical Engineering MS oral defence meeting 269 Utilizing RL to Evaluate trust Value in Wireless Sensor Networks Abstract: Wireless Sensor Networks (WSNs) is temporarily formed, operated and managed by the nodes themselves. In a complex WSN, malicious nodes are well disguised, and they can attack the entire network on specific purpose by utilizing the natural cooperation of nodes. The error-prone characteristic of sensor nodes can also cause instability in WSN. Therefore, how to choose one or more suitable sensor nodes to collaborate towards a better system performance is a critical issue. Trust model can help the elements of a network to decide whether a neighbor node is being uncooperative or malicious. Trust is more important in self-configurable and autonomous systems, such as Wireless Sensor Networks (WSN). As these networks are often deployed in open environment, so they are susceptible to be attacked by some adversaries. Traditionally cryptographic mechanisms such as authentication and encryption can avoid some of these threats. In recent years utilizing of trust management is being an important security mechanism for WSNs. In this Thesis, we propose a scalable and distributed trust model for WSNs and study the resistance of that against oscillating behavior and collusion attacks. In the proposed trust model, a node maintains direct trust value for its direct neighbors, besides with indirect trust values which is obtained by other nodes. These two direct and indirect trust values are composed to find the total trust of neighbors. Trust value is a number in interval [0,1] and it has got trust specifications. The simulation results show that our model is resistant against collusion and oscillating attacks. Also it is shown that the percentage of selection trustworthy servers is not changed in networks by different number nodes. Keywords: Wireless Sensor Networks, Trust Model, Direct Trust, Indirect Trust, Radio Range Student : Khadijeh Nakhaei Supervisor : Dr. Hadishahriar Shahhoseini Judgment Group : Dr. Shahriari, Dr. Abolhasani, Dr. Naderi Defence Date : Sunday 20.06.2010 Time : 8:00Am Place : Seminar room, School of Electrical Engineering

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سه شنبه ۲۵ خرداد ۱۳۸۹ -

Zeinolabedin Samadi

Faculty of Electrical Engineering Master of Science Defense Session 269 Relay Network Design Using Of Precoding At The Transmitter And Linear Processing At The Relays Abstract Future wireless networks are expected to provide ubiquitous high data rate coverage with reduced infrastructure cost in dense environment. Multihop transmission technique, which uses intermediate relays to aid the signal transmission from the source to the destination without increasing the signal transmission power, has emerged as an essential technique to meet this ambitious requirement. In multihop transmission systems, in one way, the interference caused by the source signals to other co-channel signals could be suppressed by transmitting at lower power level without sacrificing received signal quality. Therefore power efficiency is enhanced. On the other hand, possible detrimental shadowing effects present when the source signals propagate to the destination can be mitigated by re-transmitting the signals at the relay. As a result, with the help of relays, the source is able to transmit signals to destination possibly out of its communication range. The multiple-input-multiple-output (MIMO) transmission technology is well known to improve the spectral efficiency by transmitting multiple data streams across multiple antennas. When the channel state information (CSI) is available to all the nodes in a MIMO relay network, the covariance matrix of the signals transmitted from the antennas of S and R, or equivalently the source and relay precoding matrices can be optimally designed based on the CSI to maximize the performance measures, e.g., the instantaneous information rates. In this thesis, we aim to design a MIMO fixed relay network that uses linear processing for enhancing multiuser transmission in the downlink of a cellular system. The amplify and forward (AF) scheme and half duplex mode is considered. We employ zero-forcing dirty paper coding (ZF-DPC) at the transmitter and employ optimized power allocation in the precoder design at the base station and at the relays according to achievable sum rate at the users, neglecting the direct links from the base station to the users and with certain structure at the relays. Student: Zeinolabedin Samadi Advisor Prof. : Dr. Falahati Referee Committee: Dr. Tabataba vakili, Dr. Kahaei, Dr. Razavi zadeh Date Of Defense: Tuesday 2010/6/15 Time: 17:30 Location: Electrical Engineering Faculty Seminar Saloon

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سه شنبه ۲۵ خرداد ۱۳۸۹ -

Jamal Nazem Razavi

Department of Electrical Engineering MA Dissertation Defense Meeting Calculation of Available Transfer Capacity with considering system uncertainties and its application in transmission expansion Abstract Available Transfer Capacity is defined as the capability of transmission systems to transfer the electrical power above the level which is already committed. By now, too many methods have been proposed to calculate the value of ATC and to model this variable in operation and planning phases, but in most of them, the effects of system uncertainties have been neglected. Power systems are stochastic in nature due to the uncertain operation of their components and participants. The uncertainties associated with hourly load fluctuations and equipment unavailabilities lead to the chronological variation of different variables and states in power systems in both operation and planning phases. Line flows, bus voltages, different prices and the other variables and indices like available transfer capacity are stochastic and cannot be expressed as a determined quantity. Besides, different market participants have different criteria and objectives. This leads to more uncertainties due to the uncertainties associated with their decisions. Different uncertainties are considered in this work, in order to calculate a more reliable value for ATC. This projects the effect of stochastic nature of power systems in the value of the available transfer capacity by the Monte Carlo simulation and Stochastic Algebraic also Hybrid of two methods are studied. Then we calculate Probabality Density Function of ATC and will illustrate model stochastic ATC for transmission expansion. Student: Jamal Nazem Razavi Supervisor: Dr. Mohsen Kalantar Jury: Dr. Shahram Jadid, Dr. Hosein Heidary, Dr. Seyed Mohamad Taghi Bathaeei Time of Defense: 8:30 AM Date of Defense: 1389.3.31 Location: Seminar Hall of Faculty of Electrical

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سه شنبه ۲۵ خرداد ۱۳۸۹ -

Ali Abooee

School of electerical Engineering 269 Oral Defence of Master Thesis Design of robust controllers for hyperchaotic systems Abstract: In this thesis, robust controllers for autonomous hyperchaotic system in the presence of desirable factors such as additive matched unstructured uncertainty, external disturbance and nonlinear control input are designed. Hyperchaotic systems have two positive lyapunov exponents and are more complex than low dimensional chaotic systems. In practice, due to physical constrains, control signals may fail to be apply linearly so other nonlinear forms of assumed control signal are exerted to system which are called nonlinear control inputs. In such occasions, designed goals of closed loop hyperchaotic system must be achieved. Adopting sliding mode control as basic method to design robust controllers, different sliding surfaces such as estimative sliding surface and proportional integral sliding surface are defined. To overcome chattering phenomenon which suppose to be a major weak point in sliding mode controllers, a new approach is discussed through analysis as well as simulation results. This approach contains replacing sign function with functions such as saturation function and fuzzy function. Fuzzy function introduces fuzzy-sliding mode control in hyperchaotic systems. In addition to sliding mode control advantages, this method remove high frequency switching by fuzzy controllers. Next, in this thesis, sliding mode control and H∞ control are combined to reach following gaols: 1: Reduction of H∞ norm of the closed loop transfer function from disturbance to controlled output of hyperchaotic systems. 2: Ability to meet certain performance indices. LMI technique is used to solve H∞ problem. Considering each of designed controllers, stability of closed loop hyperchaotic systems is proved analytically. Initial studies of this thesis led to introduction of two new hyperchaotic systems which their properties are discussed. Design controllers are simulated to exhibit their strong performance. Name: Ali Abooee Supervisor: Dr. Mohammad Reza Jahed Motlagh Advisor: Dr. Zahra Rahmani Cherati Date: 19 June 2010 Time : 8:30