Show: 25 50 75 100 Results

Search results: 25 out of 1,954

مقترح بروتوكول توجيه الانترنيت الاشياء بالاعتماد على شبكات الاستشعار اللاسلكية == Proposed Routing Protocol For Internet of Things Based On Wireless Sensor Networks

Author name: عمر عبد الستار حماد
Supervisor name: ضياء جاسم كاظم
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: The routing protocol designed for Internet of Things (IoT) systems has to be adapted with different applications requirements in order to enhance the performance of IoT applications. Therefore, the main objective of this thesis is proposing a routing protocol for wireless sensor network employed to serve IoT systems. A new IoT architecture was proposed with explaining the main functions of each layer forming the proposed architecture. The proposed routing protocol acted according to the tasks specified in this architecture. In addition, an IoT application was proposed to be applicable in some utility organizations. The link quality, node depth and energy were used as metrics to make routing decisions. In this work, different cases were proposed to exhibit the usage of these metrics and show the differences of using each of them, then examine different techniques which deal with link quality and the difference between using node - to - node link quality and end - to - end link quality. Improvements were added to the proposed routing protocol to achieve the perfect integration with suitable Media Access Control (MAC) protocol with taking into consideration the behavior of IoT application. Regarding this orientation, two approaches were suggested; the first includes the proposed routing protocol, application with high data rate and MAC protocol without sleeping capabilities; while the second approach included the proposed routing protocol, application with dynamic data rate and MAC protocol with sleeping capabilities. Comparison with other protocols was essential to show the improvements achieved by this work, thus protocols designed to serve the same purpose such as AODV, REL and LABILE were chosen to compare the proposed routing protocol with. To add integrative and holistic, some of important features such as actuating and mobility were added and tested. These features were greatly required by some of IoT applications and improving the routing protocol to support them made it more suitable for IoT systems. The proposed routing protocol was simulated using Castalia - 3.2 and all proposed approaches were examined to show the enhancement achieved by each approach. The results showed better performance when using end - to - end link quality. The results also showed the effect of MAC protocol if decreasing energy consumption was required. Sleeping MAC was the best choice when used with the proposed routing protocol while reducing the data rate. The proposed routing showed better performance than other protocols did regarding Packet Delivery Ratio (PDR) and latency. It preserved network reliability since it did not generate routing or data packets needlessly. Routing protocol with added features (actuating and mobility) showed good performance. But that performance was affected by increasing the speed of mobile nodes.

تصميم مسيطر وتحليل مولد حثي ثنائي التغذية مع سرعة الرياح المتغيرة == Controller Design And Analysis of Doubly - Fed Induction Generator With Variable Speed Wind

Author name: سراج منهل حمید
Supervisor name: حسین ثاني رشك
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: The Wind Energy is one of renewable energy and has become very popular and more attractive, as a result of many factors, some of these factors are, rising oil prices, worldwide awareness of the decline in world oil production, an raise in the price of natural gas. Therefore the need for renewable energy has been very important.This work deals with Doubly Fed Induction Generator (DFIG) based wind turbine. By studying the performance of DFIG connected to the grid with constant and variable speed wind. Three cases are considered and implemented using Matlab/Simulink. The first case is studied the effect of the size of capacitance at DC - bus with constant wind speed using space vector pulse width modulation (SVPWM) switching frequency 10KHZ and two values of capacitance.The second case is studied the effect of three phase fault condition, at 33KV line.The third case is that when the input is variable speed wind, the simulation results illustrate that is with variable wind speed and conventional values of PI controllers gains the generator system behavior show increasing in rising time and maximum overshoot of generated power, the control circuit is needed for optimization to improve the generated power. This optimization can be made by tuning the controllers parameters with optimal values, so the optimization is made by using Particle Swarm Optimization (PSO). The new optimal controllers parameters(PI - PSO) make the system more efficient from the results by reducing the ripple of DC - Voltage and maximum overshoot. And the generated active power get more smooth and rising time has been reduced.

تصميم ترميز تحويل لوبي في القنوات الاسلكية == Design of Luby Transform Code Over Wireless Channel

Author name: نبيل احمد مصدق
Supervisor name: وائل عبد الحسن هادي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Communications Engineering
Degree: Master
University: University of Technology - Electrical Engineering Department - Electronic Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: ترميز التحويل لوبي) هو نوع من الترميز النافوري يعمل بدون اي معلومات عن القناة. في هذا العمل، تم تصميم LT code)) باستخدام ماتلاب، التصميم يتكون من ثلاثة اجزاء ( Encoder ,Decoder, channel ). في الجزء الخاص بتصميم الـ (Channel ) استخدمنا (( flat fading ch | Luby transform code (LT Code) is a type of fountain codes operating without any information about channel. In this work, LT code design of LT code implemented by using Mat lab as simulation software, our design consists of three parts (encoder, channel and decoder). In the channel design, flat fading channel will be used as a noisy channel to measure the performance of LT code over this type of channels. From the result obtained, SNR improvement by (30dB) at (BER=?10?^( - 4)) compared with data effect by the fading channel without coding with BPSK modulation model under different values of degree of distribution (d). Other type of modulation model (QPSK) used to measure the effect of changing the modulation type on the code performance. From the results obtained, SNR improvement by (31dB) at (BER=?10?^( - 4)) compared with data effect by the fading channel without coding. The degree of distribution (d) is a critical point of design, two types of distribution presented in this work, robust soliton distribution (RSD) and ideal soliton distribution (ISD). (ISD) works poorly in practice, (RSD) is a practical way used to get the degree of distribution in design by adding two extra parameters (c and ? ) which provide the spike element (k/R) in high degree distribution to ensure the continued of decoding process. As a result obtained the value of (c) has a major effect on the spike position on high degree (c=0.15,k/R=10 and c=0.2,k/R=7) with selective value of ?=0.5.The successful decoding probability for two types of degree distribution is very important, the value of successful decoding probability for (ISD) for low number of encoding packets (50 - 100) packet is greater than the value of successful decoding probability for (RSD). In the high number of encoding packets (>150) the value of successful decoding probability for (RSD) is greater than the value of successful decoding probability for (ISD).Encoding time for two type of distribution also discussed in this work, based on the results obtained the encoding packets time when using (RSD) is less than the encoding packets time when using (ISD).

تخمين حالة منظومة الشبكة العراقية استنادا الى تقنية امثلية الحشد الجزيئي == Iraqi Super Grid Network State Estimation Using Particle Swarm Optimization (PSO) Techniqu

Author name: انمار جاسم حميد
Supervisor name: افانين انور عبود
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: يعتبر تخمين حالة منظومات القدرة الكهربائية من الامور المهمة في تشغيل منظومات القدرة وخصوصا في حالة الحمل الزائد على شبكة الطاقة الكهربائية من خلال دوره في ضمان تشغيل اكثر اقتصاديا وامانا. تم في هذا العمل دراسة تخمين حالة منظومة القدرة واقتراح طريقة فعا | Due to the increasing stress on power system networks, state estimation recently became a main matter in the operation of power systems through its important role in ensuring the secure and economical operation of the power system. This work presents a study of a problem of power system state estimation, and proposes an efficient and reliable optimization approach to solve the power system state estimation problem. Two programs have been proposed and implemented in order to overcome the disadvantage of the classical optimization problem and search for the optimal solution of state estimation in power systems, the first program is a conventional state estimation program based on Weighted Least Square (WLS) method, and the second program is an intelligent program based on Particle Swarm Optimization (PSO) technique. All programs have been implemented using MATLAB and have been developed to solve the state estimation problem of the Iraqi Super Grid network (400kV). The proposed programs have been examined and tested on the 14 - bus IEEE and 30 - bus IEEE test standard system. The results were compared with those of the previous published papers. Then, the two programs were applied on the Iraqi Super Grid network (400 kV). The tests proved that the two methods are very efficient and suitable for on - line applications since they are concise and require few computations. The results show that the convergence of the (PSO) technique to the optimal solution is more accurate than (WLS) method. On the other hand, the PSO has an acceptable execution time compared with the freezing time of Iraqi Supervisory Control and Data Acquisition (SCADA) system approved by the Iraqi national grid.

تصميم وتنفيذ رادار تضمين التردد ذو الموجة المستمرة لنظام السرعة التكيفي للسيارات == Design And Implementation of Frequency Modulation Continuous Wave Radar For Adaptive Cruise Control of Car Applications

Author name: تمارا زهير فاضل
Supervisor name: منال حمادي جاسم
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Technology - Electrical Engineering Department - Electronic Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: The traffic accidents became significantly obsession and concern for all members of society, and has become one of the most important problems that sap physical, human resources and human potential. The researches show that the damaged property and other costs may equal 3% of world’s gross domestic product, which have been required to work in finding solutions and suggestions and put them into practice to reduce these incidents.The insertion of preventive safety applications into the car system can avoid the above mistakes. In this work, a design and implementation of Frequency Modulation Continuous Wave (FMCW) radar system working at 77GHz for Adaptive Cruise Control (ACC) technology is proposed. Using MATLAB R 2013 which is a flexible system to estimate the speed and distance in accordance to vehicle ahead, which reduces the forces on the rate of accidents by warning the driver when two vehicle become too close.Also, the principle of FMCW radar is presented to generate Linear Frequency Modulated Continuous Wave (LFMCW) sweep waveform through frequency bands with triangular frequency modulation using Voltage Control Oscillator (VCO), a triangle sweep pattern adopt will resolve ambiguity without Doppler processing. which improves the decision making before hardware implementation.Proteus Professional v8 and Micro C PRO v 6.1 compiler is used for Peripheral Interface Controller (PIC) to design a proposed collision warning circuit with PIC16F887 and RS_232 serial port to send data using USART terminal for (short, middle, large) test range.A serial communication interface is used for sending the simulation results from MATLAB FMCW radar system to hardware easy PIC v7 board with PIC16F887 to forward collision warning circuit to alerts the driver of collision risk, Liquid Crystal Display (LCD) shows radar status (short, middle, large) in accordance to range between the vehicle that FMCW radar installed and the vehicle ahead.Graphic Liquid Crystal Display (GLCD) shows the car position and road lines. Piezo Buzzer will start singing to alerts the driver from danger road.The simulation design is achieving the desired performance, one parameter warrants further attention. In the FMCW configuration, the sweep time is about 25 microseconds. Therefore, the system needs to sweep a 140 MHz band within a very short period. Such an automotive radar may able to meet the cost requirement.

تقييم اداء الكشف المباشر والمتشاكه في نظام اتصال الليفة الضوئية == Performance Evaluation of Direct And Coherent Detections In Optical Fiber Communication System

Author name: علاء عبد الزهرة جعفر
Supervisor name: علي يوسف فتاح
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Technology - Electrical Engineering Department - Electronic Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: تطورت خدمات الاتصالات بشكل متسارع في السنوات القليلة الماضية خصوصا في المسافات بعيدة المدى وبمعدل نقل البيانات بدقة عالية وخسائر قليلة في جميع انحاء العالم. وقدمت تقنيات مختلفة لزيادة سعة الارسال في انظمة اتصالات الالياف الضوئية بواسطة جمع مسارات البيانا | In recent years, there has been an extensive development of optical fiber services. They provide transmission over long distances at a high data rate with few losses all over the world. Different techniques have been introduced to increase the transmission capacity of optical fiber communication systems by a multiplexed high data rate stream into an optical fiber such as Dense Wavelength Division Multiplying (DWDM) technique. Since the deployment of DWDM technique, the focus on introducing large system capacity with high system performance, different detection techniques have been introduced to enhance the system performance with high sensitivity. In this work, two types of detection techniques (direct and coherent detection) have been evaluated and compared with each other. These detection techniques have been evaluated based on several models of encoding format such as Return to Zero - Differential Phase Shift Keying (RZ - DPSK) and Non Return to Zero - Differential Phase Shift Keying (NRZ - DPSK) at 10 Gb/s as a data rate.These systems were first simulated with a single channel to analyze the performance with no Stimulated Raman Scattering (SRS), Cross Phase Modulation (XPM) and Four Wave Mixing (FWM) effects. Whereby the system of 8×10 Gb/s is simulated at 200 GHz, 100 GHz and 50 GHz as channel spacing. Three types of dispersion compensation schemes are used in the link channel. These systems are simulated using (Optisystem version 10.0) software package. The performance of the designed systems are evaluated through Q.factor verses input power and Bit Error Rate (BER) verses Signal to Noise Ratio (SNR).The polarization interleaving is used with the WDM systems to decrease the nonlinear effects and the crosstalk arising among the adjacent channels.The obtained results of the 67% RZ - DPSK arrived to the threshold power at input power less than of the 50% RZ - DPSK, as well as the 50% RZ - DPSK system arrived to maximum Q.factor lower than 33% RZ - DPSK. This is due to the pulse duration of 33% RZ - DPSK is smaller than of 50% and 67% RZ - DPSK.The results show that the coherent detection technique has better performance than the direct detection technique. The coherent detection technique has Q.factor equal to 45, while the direct detection has Q.factor equal to 27 at the same input power ( - 5dBm), while the coherent detection technique arrived to the threshold power at the input power less than of the direct detection technique.The BER of the 33% RZ - DPSK with coherent detection with 10 Gb/s at 300 km as transmission distance achieved ?10?^( - 12.9) at SNR of 10 dB, while for the 33% RZ - DPSK with direct detection is achieved a BER of ?10?^( - 8.8) with SNR of 10 dB.The performance of the proposed systems has been improved extrusivly with increase the space channel, where the performance of the systems at 200 MHz as channel spacing has best performance than 50 MHz as channel spacing.By adapting coherent detection with 33% RZ - DPSK technique of 200 MHz as channel spacing, DWDM system can carry high data rate with long - haul transmission distance.

تصميم وبناء هوائي عريضة الشريط باستخدام المواد المسماة مابعد المادة == Design And Implementation of Ultra - Wideband Metamaterial Antenna

Author name: مروه مكي حمد
Supervisor name: طه احمد عليوي | سليمان مرتضى عباس
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Baghdad
Language: English
University location: Baghdad
First pages:
Abstract: This study focused on designing and analyzing patch antennabased metamaterial with the aid of partial ground plane. High Frequency Structure Simulation (HFSS) software was used to build and analyze a proposed unit cell of 4×4 mm² and resonant frequency of around 12 GHz. The unit cell was constructed from a patterned patch and ground plane that are connected with via through an FR - 4 substrate. The unit cell performances were studied in terms of S - parameters, effective refractive index, and dispersion properties. And it was found that the metamaterial properties appeared in the frequency band from 11 GHz to 14 GHz, where the unit cell exhibited less than 1 refractive index. A theoretical investigation based on TLM was developed to extract the values of thebasic lumped, RLC, elements network. It was found that the proposed unit cell behave like an unbalanced case of a passive constant k band elimination filter in the mentioned earlier frequency band. A parametric study based on numerical simulation was invoked to arrive to the optimal design through monitoring the effects of adding the MTM structures on the antenna performance. Therefore, this parametric study was optimized to achieve maximum bandwidth with relatively best gain.Finally, the optimal design was fabricated, measured and compared with the numerical results, obtained from Computer Simulation Technology (CST) and HFSS, in term of radiation pattern, S11 spectrum and gain. The experimental results confirmed that the gain of the antenna was 5.8 dBi at 10 GHZ with excellent matching over a wide range of frequencies. Furthermore, acceptable agreement was achieved between measured and simulated results in terms of S11 spectrum and radiation patterns at 10 GHz.

الشبكات المتعلمة الرقمية متعددة الاصناف المحورة لاغراض فحص كريات الدم الحمراء == Modified Multi - Category Digital Learning Network For Red Blood Cell Inspection

Author name: سهاد قاسم غلام حسين حداد
Supervisor name: محمود حمزة المفرجي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronic Engineering
Degree: Master
University: University of Technology - Electrical Engineering Department - Electronic Engineering Branch
Language: English
University location: Baghdad
Key words:
  • Pattern Recognition
  • RAM - based Weightless Neural Network
First pages:
Abstract: A pattern recognition system based on the n - tuple technique is developed and evaluated for use in classifying non - deterministic data with particular reference to medical image. The pattern recognition system presented in this work fulfills the requirements of simplicity and efficiency making it attractive to practical use in present day for industrial and medical environments. It is an effective solution for providing healthcare with reduced cost, especially for the rural areas and far away patients. Ordinary doctors (not specialist in blood diseases), will be able to perform extra - ordinary tasks.In this work Digital Learning Network has been designed for classification of different shapes of abnormal Red Blood Cells. Digital Learning Network is of low cost hardware and implementation, and one shot learning, using networks of RAMs. Many parameters have been investigated in details which affect the recognition rate. These parameters are presented to allow the system to be optimized, giving an increase in the performance of the system. Modification method of Feedback Digital Learning Network, which is an improving process of Digital Learning Network, has been implemented. The obtained results show that high performance (96.6%) can be achieved, providing evidence of the validity of the proposed technique.

اعادة تشكيل واضافة متسعات في قطاع توزيع كهرباء بغداد == Reconfiguration And Capacitor Placement In A Baghdad Distribution Sector

Author name: اديب ناصر حسين
Supervisor name: ثامر محمد عبد الوهاب
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: يعد تخطيط شبكات التوزيع الكهربائية من الاولويات في الوقت الحاضر في العراق نظرا للزيادة الهائلة في الاحمال الكهربائية والتوسعات المفروضة على الشبكات نتيجة التوسع العمراني الكبير والسريع.يتحقق الاداء الامثل للشبكة بتقليل المفاقيد‘ تحسين الجهد (Voltage pr | Planning of electrical distribution networks is considered of highest priority at the present time in Iraq, due to the huge increase in electrical power demand and expansions imposed on distribution networks as a result of the great and rapid urban development. Optimum performance of the electrical network is achieved by reducing losses, improving voltage profile and alleviating overload for the system components. Such operation provides for energy salvage and redundancy in the electrical network. A planning method is proposed in this work to achieve optimum operating conditions of the network by combining the network reconfiguration in conjunction with the insertion of capacitors of optimal sizing and locations. This method is classified as a huge discrete non - linear optimization problem due to the large number of variables along with the presence of constraints and objectives. The power losses and voltages in buses for all cases are obtained by backward/forward load flow method. The proposed planning of distribution networks is based on the powerful and advanced CYMDist software as a tool for the simulation of distribution networks and performing the required analysis. CYMDist is practical and efficient analysis software, which is used by many electrical companies worldwide as well as the Iraqi ministry of electricity.Optimal network reconfiguration and capacitor placement methods are tested on IEEE 33 - bus and IEEE 34 - bus test systems, respectively. The results show excellent matching as compared with previous work mentioned in the literature.The work is implemented on an actual sector from Baghdad city distribution network, which is Al_Bayaa 11kV, 145 bus, four feeders system. The presented results show that minimum active power losses with improved voltage profile had been achieved. So the network can operate normally without any constraints violation.

تصميم هوائي ضوئي يعمل ضمن نطاق تحت الحمراء الترددي باستخدام تقنية البلازمونك == Optical Antenna Design In Ir Range Using Plasmonic Technology

Author name: هادي كريم شمخي
Supervisor name: محمد ناظم عباس
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: Optical antennas, resonant structures, which efficiently collect free - space light and focus it into a nanoscale volume using plasmonic, are indispensable in the burgeoning field of nanophotonics. In this work, resonance behaviors of the fundamental resonance mode of diabolo gold metal bar optical antennas were investigated. The relationship between the near - field enhancement, absorption, and scattering spectra of localized plasmonic elements was explored. It was found that as the waist of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance increased significantly. Also reduction of the diabolo waist width caused redshift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field. Oppositely, it was found that as the length of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance decreases significantly. Also reduction of the diabolo length caused blue - shift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field.Grating surface diabolo antenna design was proposed. It was found that grating superstructure perturbed the optical properties of SPPs (Surface Plasmon polarions) and enabled the control of resonance wavelength of the antenna. The grating reduced the power that flow out from the antenna and enhanced the localized electromagnetic fields intensity. The grating also increased surface plasmon currents because of the formation of bound surface states. As a result, the absorption spectra and near field intensity were enhanced but at the same time, the scattering spectra and the far field pattern were reduced.Titanium - Gold grating surface diabolo antenna was proposed. It was found that titanium metal strengthen the grating perturbation of the optical properties of SPPs and allowed wide range of wavelength shifting (3.5 ?m). Because Gold and Titanium have difference electrical resonance characteristics, less plasmon damping occurred, resulting in lower scattering efficiency and narrower plasmon line widths.Finally, system modelling and simulations is done by using electrical department super computer (24 parallel MP and 64 GB RAM) and COMSOL multiphysics 4.4 software.

تحليل الاضطراب لتوربينة الرياح المربوطة مع منظومة القدرة == Disturbance Analysis of A Wind Turbine Connected With Power System

Author name: احمد نجم عبد الامير
Supervisor name: كنعان علي جلال
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: نظرا لزيادة الطلب على الطاقة في السنوات الاخيرة نتيجة للتوسع السكاني والصناعي ولتقليل التلوث الناتج من الوقود التقليدي والحفاظ على البيئة مما دعت الحاجة الى استخدام مصادر بديلة للطاقة, والتي يجب ان تمتاز بعدة ميزات اهمها انها صديقة للبيئة وغير قابلة للنفا | According to increasing the demand for energy in recent years as a result of the expansion of the population and to reduce pollution from conventional fuels, the need arises to find alternative sources of energy which must be characterized by several features, most important of which is friendly to the environment and sustainable. In this work, the effect of different types of disturbances on the performance of fixed speed of wind turbine generator type Squirrel Cage Induction Generator (SCIG) connected to the power system has been investigated, because it has features which make the best choice in some cases, despite the less efficiency compared with other types of generators. Also, this work aims to study and analysis the effect of (STATCOM) on the wind turbine generators because of its advantages in improving voltage stability of the grid and improving the quality of the productive power. The proposed work is performed using MATLAB/Simulink. The intelligent systems have been used to obtain the best performance in terms of extracting more power from wind energy as well as increase the stability of system in situations of disturbances and the results obtained have been compared with conventional control systems.Three types of controllers are proposed in this work; the first controller is the Proportional - Integral (PI) based on classical trial and error method, the second controller is PI - controller based on Particle Swarm Optimization (PSO) technique for optimal tuning (gain) to improve the performance of the system. The results obtained proved that the PI - controller based on Particle Swarm Optimization (PSO) technique is better than based on trial and error method. The third controller is (Nonlinear Auto regressive - Moving Average) NARMA - L2 based on (PSO). Finally, the results of the proposed controllers show that NARMA - L2 controller is more effective on the stabilization and improves the performance of the system compared with PI - PSO controller

تقييم اداء المسافية بوجود اجهزة FACTS == Distance Protection Performance Evaluation In Presence of Facts Devices

Author name: امير عقيل محمد
Supervisor name: قيس متي الياس
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: With limited enhancement or expansion of the transmission infrastructure, the contemporary power systems are operating under more stressed conditions. It becomes important to fully utilize the existing transmission system to supply load demand as much as possible, thus eliminating or reducing the need for new transmission investment. Flexible AC Transmission System (FACTS) technology provides a method to fully utilize the existing transmission lines as well as new and upgraded lines. However, the implementation of FACTS devices in the transmission system has introduced new power system dynamics that must be addressed in the area of power system protection, such as rapid changes in line impedance, line current and voltage. This thesis reports the results of comprehensive study carried out to explore the impact of mainly two of the FACTS devices, Static Synchronous Compensator 'STATCOM' and Unified Power Flow Controller 'UPFC', on the distance protection relaying system in order to identify important issues that protection engineers need to consider, that is during the stages of design and operation of the protection system. Simulation studies are carried out using MATLAB/SIMULINK. First, the distance relay has been modeled and validated with FACTS device models using test systems from literature. Then the distance relay performance is analyzed and evaluated for various fault and loading conditions in the presence of FACTS devices. A comprehensive study and results for one of the Iraqi 400kV transmission lines (KDS4 - NSRP transmission line) are presented and useful recommendations can be presented to the General Directorate of electrical Power Transmission for Middle Euphrates region / Iraqi Ministry of Electricity. II Abstract Generally, the results show that the apparent impedance seen by the distance relay would be different from that of the system without FACTS devices. Due to this, the distance relay may malfunction, resulting in undependable operation of the power system protection during faults. Furthermore, the results show clearly the dependency of the distance relay operation on many design and operational factors. These include the FACTS device type and its use purpose, the FACTS device connection point or location, the fault type and fault point location along the line, the power flow,...etc.

تبؤ الاحمال الكهربائية للشبكة العراقية للمدة القصيرة باعتماد نظام المنطق الضبابي == Short - Term Electrical Load Forecasting For Iraqi Power System Based On Fuzzy Logic System

Author name: هدى منهي عبد العباس
Supervisor name: Firas Mohammed Tuaimah
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: Load forecasting is used by participants in electric energy generation, transmission, distribution, and marketing for a variety of decision - making processes, such as economic dispatch, unit commitment, hydro - thermal coordination, transaction evaluation, and expansion planning. However, the need for accurate forecasts has intensified in the last decade due to the energy industry deregulation. Taking this into account as well as the rapid fluctuations in demand and abrupt changes in weather condition, access to reliable models for accurate forecast of load demand is essential. Due to the need for accurate load forecasts, numerous statistical and artificial intelligence methods have been proposed for the short - term load forecasting problem.In this study, the Multiple Linear Regression (MLR) method, which is one of the statistical methods, and an Interval Type - 2 Takagi - Sugeno - Kang Fuzzy Logic System (IT - 2 TSK FLS), which is one of the artificial methods and an extension of the conventional fuzzy logic system, were applied. Developed models were trained using the genetic algorithm. With the purpose of an objective assessment, the available dataset was split into training samples (80%, ????????????) and test samples (20%, ??????????). The training data used in this study covered the period from January 1, 2012 to February 1, 2012 for winter season and the period from July 1, 2012 to August 1, 2012 for summer season. The actual load forecasting period started from January 22, till 28, 2012 for winter model and from July 22 till 28, 2012 for summer model.This work suggested two models; the first model was for hourly (24 hour) load forecasting for one day ahead and the second model was for one week ahead in hourly forecasting (from one until 168 hour). For each model, winter and summer seasons were presented. The Main average percentage error (MAPE) term is an index that provides information about the bias of the model and how close forecasts or predictions are to the eventual outcomes. Experiments conducted with real datasets for the Iraqi power system showed that IT2 TSK FLS models precisely approximated future load demands with an acceptable accuracy.The real data for Iraqi power system were taken from Iraqi Operation and Control Office which belongs to the Ministry of Electricity.A computer program, written in MATLAB programming languages, was developed to represent the proposed method.

تحسين تخطيط المسار للروبوتات المتنقلة والمستقلة بالحركة باستخدام خوارزميات الامثلية القائمة على مبدا التجمعات == Improvement of Path Planning For Autonomous Mobile Robots Using Population - Based Optimization Algorithms

Author name: فرح مهدي علي
Supervisor name: نزار هادي عباس
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: Autonomous mobile robots are used in various applications such as dangerous regions. These applications demand robust and adaptable methods for path planning.Path planning optimization problem is a fundamental problem for robot navigation; its purpose is to find a collision - free path from the initial position to a target position. Many real - world optimization problems have become increasingly large, complex and dynamic, which require the development of methods and solutions whose efficiency ismeasured by their ability to find acceptable results within a reasonable amount of time.The Artificial Bee Colony (ABC) and Bacterial Foraging Optimization (BFO) algorithms are used for solving hard optimization problems, including path planning. BFO algorithm is a simple and powerful searching technique. On the other hand, Artificial Potential Field (APF) as a real time obstacle avoidance method is quite simple in theory, but it is easy to bring local minimum problem and failing to find a path in the narrow channel. Therefore, a method for hybridizing APF with BFO is introduced to make use of both methods' advantages. This thesis presents efficient and reliable four optimization algorithms to solve the path planning problem. The first two algorithms are developed based on ABC algorithm as global path planning; they specifically are modified version of ABC algorithm called Directed ABC (DABC) algorithm and a new fitness function added to ABC algorithm named Minimum Angles (MAABC) algorithm was developed. The other two algorithms were proposed based on BFO and APF algorithms as local path planning; they were namely improved versions of BFO algorithm with adaptive step size (ASBFO) algorithm and a proposed version of BFO algorithm with an adaptive tumble (ATBFO) algorithm.The developed algorithms were simulated using MATLAB R2011b package. The simulation results showed that these algorithms could find the shortest paths for even crowded environments. Moreover, these algorithmswere compared with other researchers’ work to evaluate their performance. Additionally, a comparison was made between the executing time of the proposed local path planning algorithms (ASBFO and ATBFO algorithms) and the real tracked military robot (e.g., Talon) to verify the capability of the proposed methods. Both algorithms achieved fast run time, approximately three times faster than Talon for complex environment, which made them practically efficient.

تجزئة الحزمة لالغاء الضوضاء المتكيف في تنقية الاشارة الكلامية == Subband Decomposition For Adaptive Noise Cancellation In Speech Enhancement

Author name: حوراء فاضل عبيد
Supervisor name: منال جميل الكندي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: Al-Nahrain University - College Of Engineering - Department Of Electronic And Communications Engineering
Language: English
University location: Baghdad
First pages:
Abstract: Nowadays speech processing methods are usually implemented in the time or frequency domain. Filter bank can be considered as a divide and conquer approach within signal processing, since large problems are sub - divided into many smaller problems. While filter banks are essential components of speech processing, and in signal processing in general, they will have the focus in present days. An adaptive filter is a filter that self adjusts its transfer function according to its optimizing algorithms. Least mean square algorithm has slow convergence when used with nonstationary signals like speech and it has high computational cost but normalization of step size (or input signal) leads to a useful variant of the LMS algorithm known as the normalized LMS (NLMS) algorithm, which gives better convergence characteristics than the LMS because it uses a variable step - size with respect to the input signal power.To improve the convergence rate and/or computational complexity and also to overcome the disadvantage of a full band adaptive filtering, a structure is illustrated that is subband adaptive filtering; this will converge faster at a lower computational cost for speech and white noise inputs.This research shows most types of subband decomposition structures and makes comparison among them based on their performance to cancel the noise with minimum computational complexity, maximum convergence speed and maximum noise cancellation with lowest delay.Moreover three new hybrid tree configurations or the tree decom - position are proposed to maximize the overall performance of adaptive noisecancellation system.They are given the abbreviations HTPSAF1,HTPSAF2 and HTPSAF3. These three systems use polyphase filter bank that has showed a noticeable increase in the convergence speed and large reduction in the computational complexity due to the lower number of coefficients that can be achieved for the analysis/synthesis filters, which in turn will result in minimum delay in the reconstructed output speech signal.The algorithm of subband decomposition structures has been described theoretically then modeled under MATLAB simulation program using built - in filters and real input signals.

تصميم وتنفيذ منظومة مقاييس متوزعة ذكية == Design And Implementation of A Smart Distributed Metering System

Author name: مهند غازي خميس
Supervisor name: عدي عبد اللطيف عبد الرضا
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Baghdad
Language: English
University location: Baghdad
First pages:
Abstract: This work is concerned with designing and implementing a smart energy metering system that consists of two smart energy meters and a billing center. The designed smart energy meter is a single phase meter in which the amount of consumed energy is calculated using PIC18F45K22 (which is a Peripheral Interface Controller (PIC)) and utilizing ACS758 (which is a Hall - effect based liner current sensor Integrated Circuit (IC)).The amount of consumed energy is sent to the billing center (which is implemented by using a laptop) for issuing the bills. The billing center receives the consumption data and sends the switching commands by utilizing an external communication technology. After comparing various communication technologies, ZigBee is chosen for this work.Two smart energy meters are implemented to test various communication conditions, such as multi - hopping. The design of the two smart energy meters differ only in the ZigBee addresses in the network.The program for the PIC's in the smart meters is written with MikroC PRO V6.0.1, while the program for the laptop in the billing center is written with Visual BASIC 6.

تحسين استقرارية منظومة الشبكة العراقية (kV 400) باستعمال افضل جهاز من اجهزة ال FACTS == Stability Improvement of The (400kV) Iraqi Grid Using The Best FACTS Device

Author name: شيماء شكري عبد الحليم
Supervisor name: رشيد حميد الربيعي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering - Power and Machinery
Degree: Master
University: University of Technology - Electrical Engineering Department - Electrical Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: يعتبر نظام القدره الكهربائيه من الانظمه الضخمه والمعقده لاحتوائها على عدد كبير من محطات التوليد وخطوط النقل واجهزة السيطرة لذلك فانه يخضع الى تغيرات مفاجئه في مستويات الحمل، حيث اصبح من الصعب جدا الحفاظ على نظام مستقرمع التغيرات التي يشهدها النظام, لذلك | Electrical power system has become large and complicated so it is susceptible to sudden changes in load levels. Stability is an important concept which determines the stable operation of power system.The modern trend is to employ Flexible Alternating Current Transmission System (FACTS) devices in the system for effective utilization of transmission resources. The FACTS devices contribute to power flow improvement besides they extend their services in transient stability improvement as well, study and analyze the stability of system through rotor angle and voltage. The objective of this work is to improve the transient stability of the Iraqi National Super Grid System (INSGS) by using best FACTS device in different optimal locations under fault conditions. Two test systems are studied, the first system is IEEE 9 - bus test system, and the second system is the Iraqi (400 kV) electrical network 24 - bus bars, three phase to ground fault, temporary fault and permanent fault are tested. The load flow program was implemented using Newton - Raphson method and the numerical solutions of non - linear differential equations are solved using Trapezoidal method. The programs that are used in this work are implemented using MATLAB 7.12.0(R2011a) package based on Power System Analysis Toolbox (PSAT version 2.1.6)software.copyright © 2002 - 2010 by Federico Milano as Graphical User Interface. A comparison has been made between five types of FACTS (UPFC, SSSC, TCSC, SVC, STATCOM) at optimal locations of the Iraqi grid and 9 - bus test system to get optimal FACTS devices by (voltage stability and rotor angle stability). The results obtained show that Unified Power Flow Controller (UPFC) is an optimal device for improvement the stability by damping the voltage and rotor angle oscillations.

التشوه بالتوافقيات في اشارات التدفق للمتحسس السعوي الحيزي المثبت خارجيا == Harmonic Distortion In The Flow Signals of Externally Mounted Capacitive Spatial Filter

Author name: مروه مالك حسوني
Supervisor name: عباس احمد الشالجي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: Al-Nahrain University - College Of Engineering - Department Of Electronic And Communications Engineering
Language: English
University location: Baghdad
First pages:
Abstract: This thesis investigates the performance of some windows on the flow signals that are generated from the planar capacitance spatial filter (PCSF) according to the moving of the solid particle in the channel of the filter. The sensor that operates as non - invasive device for solid flow measurement utilizes the thin wall of a dielectric pipe section as a shielding layer to protect the sensor from erosion, rust and moisture, and to make it more versatile.The finite - difference model equations are solved using successive over relaxation (SOR) methods. The waveforms show that the response of the PCSF is spatially - biased towards particle flowing closer to the plane of sensing electrodes and that the resulting flow signal is non - sinusoidal. The SOR method that is used to compute the PCSF potential fields has been investigated using a mesh of 110 by 32 nodes, and the algorithm was programmed in MATLAB (Release 2013a) using an Intel core ™ i3 PC,CPU processor.To study the effect of the total harmonic distortion (THD) content on the flow signals that are calculated with respect to the fundamental frequency of the power spectrum density through a specific quantitative criterion, this work comprises a comparative study among three types of windows; Hanning, Hamming, and a subOptimal window called the Kaiser window.The effect of particle flying heights, relative permittivity and size on the THD of the flow signal were examined. It was found that theTHD of flow signals at heights closer to the plane of sensing electrodes is high and decreasing gradualy when the particle flying height is far above the sensor. All the three windows used in this work have better suppression of harmonics distortion as compared with unwindowed (raw) flow signal.

تمثيل وتنفيذ العاكس ثلاثي الطور رباعي السيقان بواسطة طريقة المتجه الفضائي بتضمين عرض النبضة == Modeling And Implementation of Space Vector PWM Four - Leg Three Phase Inverter

Author name: لؤي كمال عبد القادر
Supervisor name: فاضل عباس مهدي القرملي
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electrical Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: The thesis considers a three - phase four - leg inverter, which is used to supply unequal loads without using a transformer. In the literatures, a three - dimensional modulation technique, requiring complex mathematical algorithms were proposed for this kind of inverter. In this research a different approaches are discussed through two kinds of controller; first type is based on the separation control method of the fourth - leg of the inverter from the other phases for one type for modulation. This research applied to the three - phase inverter of the traditional SVM techniques avoiding the employment of complex procedures. The voltage modulation method based on a triangular carrier waveform for the three - phase four - leg voltage source converter. The four - leg converter can produce three - phase output voltages independently from the additional forth - leg. The proposed modulation method for the four - leg inverter is implemented with a single carrier by a simple useful “offset voltage” concept. The second type is equivalent to the so - called three - dimensional space vector PWM method, but its implementation is much easier. The simultaneously synthesized equations of the maximum magnitude of unbalanced three - phase voltage.The feasibility of the proposed modulation technique types verified by computer simulation and experimental results. These results show that both types of “Carrier - Based Pulse Width Modulation (PWM) technique” and “Three Dimensional Space Vector Modulation Technique” are easier implemented than conventional type by using microcontroller component (PIC16F874A/877A) instead of digital components (DSP & FPGA). So this thesis offers a prototype for this circuit with low cost and low harmonics, but with more complex control circuit.

تحليل الاتصال بين القمر الصناعي والطائرة باستخدام نموذج تعقب الشعاع == Analysis of Satellite - To - Aircraft Communications Using Ray Tracing Model

Author name: علي محمد علي
Supervisor name: جابر سلمان عزيز
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Communications Engineering
Degree: Master
University: Al-Nahrain University - College Of Engineering - Department Of Electronic And Communications Engineering
Language: English
University location: Baghdad
First pages:
Abstract: While the aircraft flying above the earth surface, the signal transmitted from the satellite to the aircraft suffered from changes in it's characteristics at the aircraft receiver's antenna according to many factors affecting the direct and reflected power from the earth surface such as the distance difference, the nature of the earth surface, elevation angle, Doppler shift, etc… This Thesis introduces a proposed algorithm to analyze and simulate the communication link between the Satellite and the aircraft taking into account all the parameters that affect the magnitude of the power and signal characteristics received at the aircraft antenna. The proposed method uses the ray - tracing technique in this simulation to analyze the communication link between the Satellite and aircraft. The simulation developed in this thesis has minimized the error percentage as much as possible taking into account most of the factors that might affect the characteristics of the signal received by the aircraft from the satellite. This simulation considers the free space loss, specular reflection losses, scattering factor, earth curvature effect, etc…,also the simulation takes into account the Doppler effect that caused by the aircraft movements. The simulation measures the received signal strength and fading characteristics of satellite to aircraft communication to determine the effectiveness of communication and to establish parameters which can be useful to the communication system designer in Iraq and the rest of the world. MATLAB® v6.5 used in the simulation as application software, the simulation also applied to MATLAB® v7.0.

تحليل المسار النازل لنظام الاتصال اللاسلكي التكيفي المتعدد المداخل والمخارج والمستخدمين == Analysis of Adaptive Downlink Multiuser Mimo Wireless Communication System

Author name: عمر جبار ابراهیم
Supervisor name: رعد سامي فياض
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Communications Engineering
Degree: Master
University: Al-Nahrain University - College Of Engineering - Department Of Electronic And Communications Engineering
Language: English
University location: Baghdad
First pages:
Abstract: Multiple - input multiple - output (MIMO) wireless communication systems have received significant attention due to their enormous channel capacity potential in rich scattering environment. Such systems need to consider multiuser transmission / reception in their design. This thesis investigates theoretically the ergodic capacity of multiuser MIMO systems operating with adaptive techniques to enhance their performance. The ergodic capacity of multiuser MIMO system is analyzed and simulated for three types of channels : additive white Gaussian noise (AWGN) channel, uncorrelated Rayleigh fading (URF) channel, and semicorrelated Rayleigh fading (SRF) channel. The downlink SRF channel for each user is modeled by assuming that the fading is correlated at the transmitter but uncorrelated at the receiver side. The simulation results are compared to those related to a single - user system and used as a guideline to present an adaptivetechnique to enhance the capacity of MIMO system operating in SRF channel. The adaptive technique is based on a tradeoff between time division multiple access (TDMA) and block diagonalization (BD).Simulation results are presented using MATLAB environment to address the dependence of ergodic capacity of a MIMO communication on various system and channel parameters. The results indicate clearly that the threshold level of angle between users ? employed in the adaptive system must be chosen carefully to maximize the ergodic capacity. The optimum threshold ?th is equal to 24°, 42° and 47°, for angle spread ? = 5°, 50° and 75°, respectively

طرائق الكشف للتضمين الترددي المتعامد للرابط النازل في نظام تطور طويل الامد (LTE) == Detection Methods For Ofdm Downlink In Long Term Evolution (LTE) System

Author name: اكرم جبار عبد الحسين حسن
Supervisor name: يمان اسماعيل مجيد
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Baghdad
Language: English
University location: Baghdad
First pages:
Abstract: GPP3 التطور على المدى الطويل (LTE) هو تقنية الجيل الرابع اللاسلكية ذات النطاق العريض. هدفه الرئيسي هو تعزيز الكفاءة الطيفية باستخدام تقنيات التضمين الترددي المتعامد بالتقسيم (OFDM). ومع ذلك، ياتي هذا التحسن في الاداء بزيادة التعقيد الحسابي في اجهزة الاستق | 3GPP Long Term Evolution (LTE) is the fourth generation mobile wireless broadband technology. Its key objective is to enhanced spectral efficiency by using Orthogonal Frequency Division Multiplexing (OFDM) techniques. However, this performance improvement comes at the cost of increased computational complexity in the receiver. The goal of this work is to introduce a detection method that gives a better performance with reasonable computational complexity for LTE mobile communication system. An approximated linear baseband model for the two modulation techniques used by the LTE system (which is the Quadrature Phase Shift Keying (QPSK) and sixteen - level Amplitude Modulation (16 - QAM)) have been derived. Three receivers have been simulated and tested. The three receivers use Least Square (LS) channel estimator. These receivers uses channel compensator, decision feedback equalizer and perturbation algorithm. The LTE communication system has been simulated using MATLAB®7 programming language. The results of the computer simulation show that the perturbation algorithm gives an enhancement in the receiver performance of about 2 dB in different mobile channels than decision feedback equalizer and about 5 dB than channel compensator at the 10 - 3 of BER.

بناء خوارزمية تزامن لانظمة (OFDM) باستخدام معالجة الاشارة الرقمية == Dsp - Based Synchronization Algorithm Implementation For OFDM System

Author name: رائد ستار جبر
Supervisor name: محمود عبد القادر عبد الستار
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language: English
University location: Baghdad
First pages:
Abstract: تعدد الارسال للتردد بالتقسيم المتعامد (OFDM) هو مفتاح تمكين التكنولوجيا لمعظم انظمة الاتصالات اللاسلكية الحالية ذات معدل نقل البيانات العالي. والميزة الرئيسية للـ (OFDM) مقارنة بالطرق التقليدية هو انه يحول القناة ذات النطاق العريض الى قنوات فرعية ضيقة متو | Orthogonal Frequency Division Multiplexing (OFDM) is the key enabling technology for most current high data - rate wireless communication systems. The primary advantage of OFDM over conventional schemes is that it converts a wideband channel into parallel narrowband sub - channels allowing relatively simple channel estimation and frequency domain equalization. It is as an effective technique for coping with channel impairments like multipath propagation and Inter Symbol Interference (ISI) by making use of an appropriate cyclic prefix. One of the major drawbacks of OFDM is that it is more sensitive to synchronization errors than its single carrier counterparts. This thesis describes a real - time implementation of a timing and frequency synchronization for OFDM system using MATLAB software Simulink, DSP processor TMS320C6713 and Code Composer Studio (CCS). The hardware interface converts the baseband signal from the PC to the DSP Processor. Basic transmission and reception performances are evaluated in real time using Real Time data Transfer (RTDX). The practical results and performance evaluation of the synchronization algorithms in OFDM system is presented and discussed. The results are plotted for different offsets of CFO and STO with different values of signal to noise ratio. Also the bit error rate (BER) and the mean square error (MSE) of the system is analyzed. The results show that the time offset more effect than frequency offset because of ISI and ICI occurs when time offset occur in the system. The synchronization algorithm is found to be robust for both CFO and STO simultaneously. It can handle offset of about CFO = 500 Hz and STO = 14 samples simultaneously without wasting extra bandwidth. This algorithm used for synchronization more robust for 16QAM compared with 4QAM modulation.

التركيب السليكوني النانوي في الخلايا الشمسية == Nanostructured Silicon Based On Solar Cells

Author name: نور احمد سلمان
Supervisor name: ثائرة زكريا الطيار
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Electronic Engineering
Degree: Master
University: University of Technology - Electrical Engineering Department - Electronic Engineering Branch
Language: English
University location: Baghdad
First pages:
Abstract: تعتبر الخلايا الشمسية تكنولوجيا واعدة وقابلة للتجديد حيث ازداد الطلب عليها نتيجة لزيادة الاهتمام بالطاقة الكهروضوئية. ان التحسين المستمر لكفاءة الخلايا الشمسية بايجاد التقنيات والمفاهيم الجديدة يجب ان يمتد على نحو متزايد باعتبارها واحدة من اهم مصادر الط | The demand for solar cells has been growing rapidly with an increasing social interest in photovoltaic energy. The improvement of energy conversion efficiency of solar cells is performed by developing the technology and concepts that have been increasingly extended as one of the key components in our future global energy supplement. But, the main problem of photovoltaic modules are their rather high production and energy cost. Three generations of solar cell technologies have been established in the previous century.Nanostructured silicon substrates based on p - type crystalline Silicon (c - Si) have been prepared in this work. Electrochemical Etching (ECE) of the Silicon (Si) wafers in Hydrofluoric (HF) acid was employed to synthesize porous layers consisting of silicon nanostructures. The process was carried out at different etching time and different current densities which are considered as effective parameters in ECE process. It is found that a homogeneous porous layer could be obtained with porosity value of (87%) when the current density is (60 mA/ cm2) and the etching time of (10 min). Among the Transparent Conductive Oxide (TCO) materials available, Zinc Oxide (ZnO) films show promising electrical and optical properties in combination with low cost alternatives. It can function as Anti - Reflecting Coating (ARC), window material, transparent electrode and active layer in heterojunction solar cells. n - type ZnO thin films are grown on p - type nanostructured silicon substrates by using Pulsed Laser Deposition (PLD) technique with Q - switching Nd : YAG laser beam Second Harmonic Generation (SHG) [?=(532 nm), number of pulses (140) pulses, and laser energy (820 mJ)], vacuum of (10 - 3 Torr), ambient oxygen pressure of (10 - 1 Torr), and substrate temperature of (400 °C). The morphological, optical, chemical and structural properties were investigated using Atomic Force Microscopy (AFM), Ultraviolet - Visible (UV - VIS) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and X?Ray Diffraction (XRD) techniques, respectively.Surface morphology and optical properties results show densely packed highly crystalline growth of ZnO thin film on nanostructured silicon substrate grown at optimum condition with an average grain size around (88.57 nm). The average roughness, root mean square, and ten - point height estimated from AFM quantitative analysis, are found to be (3.02 nm), (3.62 nm), and (8.76nm) respectively. The thickness is calculated and found to be (100 nm). The film shows high transparency (above 80%) and the estimated Energy - gap (Eg) is found to be about (3.4 eV). This is important for its applications as transparent conductive films and solar cell windows. The chemical and structural properties results characterize ZnO at (420 cm - 1) and (766 cm - 1) absorption bands respectively and the thin film is polycrystalline with hexagonal Wurtzite structure.

محاكاة GSM/EDGE وGSM لنظام الاتصالات المتنقلة == Simulation of GSM And GSM/EDGE Mobile Communication Systems

Author name: اسامة علي عبد الله
Supervisor name: رعد سامي فياض
General topic: Electrical, Electronic and Communications Engineering
Specific topic: Communications Engineering
Degree: Master
University: Al-Nahrain University - College Of Engineering - Department Of Electronic And Communications Engineering
Language: English
University location: Baghdad
First pages:
Abstract: The introduction of global system for mobile communication (GSM) air interface has undoubtedly created a new area in telecommunications. In view of its extensive use in real world applications, it is highly desirable to further investigate the performance of the GSM system under different operating conditions and environments. Furthermore, there is increasing interest in using high - level modulation to provide enhanced data rate for GSM evolution (EDGE).This thesis investigates the performance of both GSM and GSM/EDGE systems operating in Raleigh fading channel. The results are reported for different models of fading channel in order to describe various environments. A detailed SIMULINK model is developed in MATLAB environment to simulate the GSM system. Furthermore, a MATLAB software package is developed to simulate extensively the EDGE system. Both simulation models are handled to characterize each essential part in these systems. The simulation takes into account channel coding, modulation type, interleaving and burst building, multipath channel effect, channel estimation, and detection process.The simulation results indicate clearly that to achieve a bit error rate (BER) of 1x10P - 5 P in additive white Gaussian noise (AWGN) channel, the signal - to - noise (SNR) ratio should be 5.25, 3.75 and 12.25 dB when GSM, MCS - 1 EDGE (GMSK modulation), and MCS - 7 EDGE (3?/8 - 8PSK modulation) systems are used , respectively. These values are to be compared with R12R.43, R1R0.21 and R2R1.05 dB, respectively, for HT100 - type fading channel. The MSC - 1 system offers the best BER characteristics followed by GSM system. The MCS - 7 offers the worst BER characteristics among the three systems.
1 ... 42 43 44 45 46 ... 79