Show: 25 50 75 100 Results

Search results: 25 out of 1,954

تحري سريان القذرة المستمرة مع اضافه متسعات التوازي في شبكه التوزيع الكهربائية == Investigation of Continuation Power Flow and Capacitor Placement in Electrical Distribution System

Author name: علاء سعد حسين
Supervisor name: قاسم عبد الرزاق الانباري
Degree: Master
Language: English
University location: Baghdad
First pages:

التعرف على الشخص اعتمادا على القزحيه الملونه البيومتريه والتحويلات الكونتورية == Person Identification Based on Colored Iris Biometric and Contourlet Transform

Author name: ضحى حسين حميد
Supervisor name: ماهر خضير محمود
Degree: Master
Language: English
University location: Baghdad
First pages:

تحسين اداء منظومات الطيف المنتشر المتعدد الوصول بالقفز الترددي باستخدام المتتاليات الفوضوية == Enhancing the Performance of Frequency Hopping Multiple Access Spread Spectrum System Using Chaotic Sequences

Author name: سهاد قاسم نعيم
Supervisor name: ماهر خضير محمود العزاوي
Degree: Master
Language: English
University location: Baghdad
First pages:

اداء السرعة للمسيطر الاتجاهي لمحرك تزامني بمغناطيس دائم مغذى بمحول مصفوفة غير مباشر == Speed Performance Based Vector-Controlled Permanent Magnet Synchronous Motor Fed by Indirect Matrix Converter

Author name: زينب محمود عبد
Supervisor name: تركي كحيوش حسن
Degree: Master
Language: English
University location: Baghdad
First pages:

تصميم وتحليل هوائي متغير الرقعة لتطبيقات Wi - Fi وWiMAX == Design and Analysis of Microstrip Patch Antenna for Wi-Fi and WiMAX Applications

Author name: زينب سعدون جميل
Supervisor name: رعد حمدان ظاهر
Degree: Master
Language: English
University location: Baghdad
First pages:

تاثير توزيع مستخدمي النقال في سعة انظمة الاتصالات الوصول المتعدد بتقسيم الزمن وتقسيم الترميز == Mobile Distribution Effect on TDMA and CDMA Capacity

Author name: دلال كنعان طاهر
Supervisor name: عضيد حسن سلومي
Degree: Master
Language: English
University location: Baghdad
First pages:

تصميم ومحاكاة وبناء ملف حثي لاغراض التقسية السطحية لمسنن من الفولاذ الكاربوني CK-45 == Design, Simulation and Implementation of an Induction Coil for Surface Hardening of a Carbon Steel (CK-45) Gear

Author name: حمدان فراس صبيح
Supervisor name: عصام محمود عبد الباقي | صاحب محمد مهدي
Degree: Master
Language: English
University location: Baghdad
First pages:

تصميم هوائي شريطي دقيق ذو نطاق فائق الحزمة الترددية (UWB) ذو خصائص قطع الحزمة == Design of UWB Microstrip Antenna with Band Reject Characteristics

Author name: براء علي كريم
Supervisor name: عضيد حسن سلومي
Degree: Master
Language: English
University location: Baghdad
First pages:

تخمين خسائر المحرك الحثي ثلاثي الطور بواسطة طريقة العنصر المحدد == Losses Estimation of Three Phase Induction Motor by Finite Element Method

Author name: احمد نعيم عبد الصاحب
Supervisor name: عامر مجبل علي
Degree: Master
Language: English
University location: Baghdad
First pages:

تحليل وتصميم منظومة فوتوفولتائية تغذي مضخة ري ذات محرك حثي ثلاثي الطور باستخدام تقنية تضمين عرض النبضة للمتجه الفضائي == Analysis and Design of a Photovoltaic System Fed Three-Phase Induction Motor as Irrigation Pump Using Space Vector Pulse Width Modulation Technique

Author name: احمد ثائر محسن
Supervisor name: عصام محمود عبد الباقي
Degree: Master
Language: English
University location: Baghdad
First pages:

توزيع المجال الكهربائي لمحولة 33\0،416 كيلوفولت وتقييم العوازل باعتماد طريقة العنصر المحدد == Electric Field Distribution of 33/0.416kV Transformer and Insulation Assessment Based on FEM

Author name: ابراهيم جليل جبر
Supervisor name: قاسم رشيد حميد
Degree: Master
Language: English
University location: Baghdad
First pages:

بوابات CNOT حتمية مقترحة مبنية على التحويل الفوتوني المتشاكه == Proposed Deterministic CNOT Gates Based on Coherent Photon Conversion

Author name: جواد عبد الكاظم حسن
Supervisor name: Khalil Hajim
Degree: Doctorate
University: University of Baghdad
Language: English
University location: Baghdad
First pages:

تصميم وتنفيذ قناة المتكيفة لنظام الاتصالات المتنقلة باستخدام مصفوفة البوابات المنطقية المبرمجة == Design and Implementation of Adaptive Channel for M - ary Mobile Communication System Using FPGA

Author name: وسن سمير رشيد
Supervisor name: هادي طارش زبون
Specific topic: Electronic Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:

تصميم و تصنيع هوائي شقي من النوع الجزئي لتطبيقات الاتصالات اللاسلكيه ثنائية النطاق الترددي == Design and Fabrication of Printed Fractal Slot Antennas for Dual - band Communication Applications

Author name: سيفان فهمي عبد الكريم
Supervisor name: جواد كاظم علي
Specific topic: Communications Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:

دراسة وتحليل الاظمحلال في قناة النظام الخلوي GSM == A study and analysis of fading in GSM mobile channel

Author name: علاء عدنان سليم
Supervisor name: عايد خلف السامرائي
Specific topic: Communications Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:

تقليل استهلاك القدرة في تصميم دوائر السيموس المتكاملة بالاعتماد على الخوارزمية الجينية == POWER MINIMIZATION IN CMOS INTEGRATED CIRCUITS DESIGN BASED ON GENETIC ALGORITHM

Author name: علي طويج شاهين
Supervisor name: سليم محمد رضا طه
Degree: Doctorate
University: University of Baghdad
Language: English
University location: Baghdad
First pages:

تكامل منظومة الملاحة INS/DGPS) (لمرحلة هبوط الطائرة == Integration of (INS/DGPS) System For Airplane Landing Phase

Author name: هدى ناجي عبد الرضا
Supervisor name: فرج محل محمد | سمير عبد الخالق عزيز
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: تستخدم على نحو متزايد في )INS( ومنظومة الملاحة )GPS( منظومة تحديد الموقع العالمي مجموعة واسعة من التطبيقات. منظومة تحديد الموقع العالمي هو نظام الملاحة الذي يوفر درجة الاشارات على الاقل )GPS( عالية من دقة تحديد الموقع وتقدير السرعة للمستخدم. يتلقى مستلم م | Global positioning system (GPS) and Inertial Navigation System (INS) are increasingly used for positioning and attitude determination in a wide range of applications. The GPS is a navigation system which provides highly accurate position and velocity esti

حساب توزيع الطاقة الممتصة في راس الانسان باستخدام نطاق الفرق الزمني المحدد لانظمة الاتصالات المتنقلة == Computation Of Sar Distribution In Human Head For Cellurlar Mobile Communication Systems Using Fdtd

Author name: هويدا كمال عبد الفتاح
Supervisor name: عضيد حسن سلومي
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: Widespread wireless communications system in the last few years, leads people to ask many questions about the advantages and disadvantages of those systems, especially about electromagnetic waves pollution and their effect on human health.The mobile device is frequently used by the general public from adult to child, one of the main sources of electromagnetic waves and very close to the human head. Therefore the focus of this research on the impact of electromagnetic waves from mobile to human health by measuring the Specific Absorption Rate (SAR), at the human head and the hand through SEMCAD - X that uses the Finite Different Time Domain (FDTD). SAR computation uses (FDTD) in the way the limited space of time, to calculate the specific absorption rate. The results have been compared with standards averaged over any 1 g of tissue and averaged over any 10 g of tissue. It didn't exceed the applicable standard.This work evaluates specific absorption rate (SAR) at different ages of three people. Firstly, old man, who was estimated to head 100% size of header used in the program SEMCAD - X. Secondly Adult man was estimated his head by 85% size of header used in program, and finally the child who was estimated his head by 65% size of header used in the program SEMCAD - X, the design hand has been used with all cases.The design of the mobile phone software works in four different packages of frequencies; the packets are the center frequencies 900MHz 1800MHz, 2100MHz and 2400MHz, when increased frequency the SAR increased but in the some state and frequency decreasing.The Evaluation of SAR in the head and the hand of the user device and the generic phone, the highest value of SAR decreases with increasing distance between the generic phone and the user's head and reducing the proportion was 50% for the old man, 40% for adult man and 35% for child. It can be noted that the angle of the rotation of the various frequencies is not fixed, while the ratio approximately is 25% for each angle of rotation.Also, it can be noted that for fixed frequency, the input power is increased to a double and the SAR have been used increased almost to a double.The different positions show that the methods of holding generic phone have a significant impact on the value of SAR. Therefore, the value of SAR can be reduced into 90% when using the correct method.The evaluation of SAR in these cases shows their influence on children and it was much greater than the adult human or old human by parentage 40% old man and 35% adult man.

تمييز الحروف العربية المعزولة المكتوبة بخط اليد باستخدام الشبكات العصبية == Recognition Of Isolated Handwritten Arabic Letters Using Neural Networks

Author name: نهلة ظاهر حبيب بهية
Supervisor name: منذر نعمان التكريتي
Specific topic: Electrical Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: يتناول هذا البحث مشكلة تمييز الحروف العربية المعزولة المكتوبة بخط اليد باستخدام الشبكات العصبية. ان نظام تمييز الحروف العربية المقترح يتكون من ثلاث مراحل وهي : مرحلة مسح صور الحروف العربية ثم مرحلة معالجة الصور واخيرا مرحلة التدريب والتصنيف.ان المرحلة الاخ | This thesis presents an algorithm for recognition of an off - line isolated handwritten Arabic letters using neural networks.The handwritten recognition system present in this work consists of three modules : - 1 - Arabic letter scanning module 2 - Arabic letter preprocessing module 3 - Learning and recognition module.The proposed neural network in the third module is trained in two stages : The first stage employs Self - Organizing Map learning algorithm for clustering the input pattern, which are based on a database of 196 letters collected from 7 independent persons.In the second stage each of the similar output cluster is considered as a subnet introduced to neural network trained by Back - propagation learning algorithm for classification. Several networks architecture are designed in the second stage using 1 - hidden and 2 - hidden layers with 5 and 28 output nodes in the output layer with different number of hidden nodes and learning rate.To examine the efficiency of the system a database of 196 letters collected from other 7 independent persons are used, (in order to test the ability of the trained network to generalize). The results show that clustering the input pattern, using 1 - hidden layer and 28 nodes in output layer improve the network performance. The system was implemented using (IBM - PC) of type Pentium 3.The programming language used to design the system was c++ version 5.02.

استراتيجية السيطرة على المقوم ثلاثي الاطوار المضمن بعرض النبضة (PWM) نوع رافع للجهد ولمصدر تغذية متغير الحالات

Author name: منتظر كاظم عبد الله
Supervisor name: تركي كحيوش حسن
Specific topic: Electrical Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: In this thesis, a proposed control strategy is presented to improve the performance of the PWM boost type rectifier when operating under different supply voltage conditions (balanced, unbalanced, and distorted three - phase supply voltages). The proposed control strategy is classified into two parts, the first part is voltage controller and the second part is current controller. In the voltage controller, Repetitive Controller (RC) is used to reduce the even order harmonics in the regulated output dc voltage (5.62V (P.P.)) so small output capacitor (480µF) is used instead of large capacitor (920µF) that is used with the conventional controller (PI controller connected in series with a LPF). RC also reduces the even order harmonics (0.014A (P.P)) which appears in the reflected dc current (IMAX), this leads to reduce the odd order harmonics (0.01A) which appears in the input currents. While in the current controller, enhanced Phase Locked Loop (EPLL) technique is used to obtain sinusoidal and balanced three phases, to construct the reference currents, which are in phase with the fundamental supply voltages Therefore, the supply - side power factor is kept close to unity (0.9036 for extremely distorting case). As a result the calculations of the reference currents in the proposed control strategy does not require Clarke or Park transformations, the same for the calculations of the positive or negative sequence components. A proportional controller is used to give excellent tracking between the line and the reference currents. Using this approach makes the control strategy easy to understand and also it saves calculation time of the control algorithms if implements in real time. The complete system with the proposed control strategy is simulated using Matlab/Simulink (Version 2012). The obtained results for the complete system using repetitive voltage controller are compared to the results of the system with using the conventional voltage controller. The results with the repetitive controller show better responses and stable operation in the steady state under different input voltage conditions, as well as in the transient response under different disturbances.

مبدل فوتوفولطائي مايكروي احادي المرحلة نوع فلايباك المغذي للشبكة == Single Stage Grid - Connected Flyback Photovoltaic Microinverter

Author name: مصطفى عباس فضل
Supervisor name: تركي كحیوش حسن
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: Solar energy systems based on photovoltaic (PV) cells have attracted considerable interest in recent years due to their abilities of clear and seemingly limitless generated energy. Solar energy systems based on microinverter architectures are earning in publicity as they are less prone to shading and PV cell malfunction since each PV panel in the system has its own low power inverter.In this thesis two alternative modes of operation for the current source flyback microinverter are suggested : the discontinuous conduction mode (DCM), where a constant switching frequency (CSF) control method is applied, and the boundary conduction mode (BCM) between continuous conduction mode (CCM) and DCM, where a variable switching frequency (VSF) control method is used. These two control methods are analytically studied and compared in order to establish their advantages as well as their suitability for the development of an inverter for grid - connected PV applications.An optimum design methodology is developed, aiming for an inverter with the smallest possible volume for the maximum power transfer to the public grid and wide PV energy exploitation. The main advantages of the current source flyback microinverter are very high power density and high efficiency due to its simple structure, as well as high power factorregulation. The design and control methodology are validated by Powersimulation software (PSIM) and a laboratory hardware prototype is buildusing analogue and digital devices.The microcontroller type (PIC - 18F45K22) is used to implement perturb and observe (P&O) maximum power point tracking (MPPT) algorithm, and C language is used for programing the microcontroller. The simulation and experimental results are obtained to verify the proposed flyback microinverter.

تحقيق دائرة المعدل الثابت للانذار الكاذب باستعمال منظومة البوابات المنطقية المبرمجة موقعيا == Modified GO - CFAR Implementaion Using FPGA

Author name: مصطفى صبحي كمال
Supervisor name: رفعت طالب حسين | حكمت نجم عبد الله
Specific topic: Electrical Engineering
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: هذه الاطروحة تتعلق بتحليل ومعالجة تاثير الضوضاء المحيطية (Clutter) لمنظومة الرادار النبضي، يتطلب رادار الكشف الالي للهدف استعمال عتبة الية (Adaptive threshold) لتحقيق معدل ثابت للانذار الكاذب وذلك لغرض السيطرة على الانذار الكاذب الذي تسببه تغيرات في الضوض | This thesis deals with the analysis and processing of clutter for pulsed radar system. Automatic target detection radar requires adaptive thresholding achieved by Constant False Alarm Rate (CFAR) circuit in order to control the false alarm caused by variations in clutter background.This work focus on worst radar environment that happens when abrupt variation in clutter background merged with multi - interfering target, to detect target in such environments it need robust CFAR algorithm that excise the target spikes and clutter edges from CFAR window in order to give best possible estimation to the noise background. two important algorithms studied which are CA - CFAR and OS - CFAR algorithms in additional to the modified CA - CFAR algorithm. All these algorithms were simulated with mat lab v6.1 and applied them to three different clutter models that represent different environment cases the CA - CFAR family failed to handle model two and three also OS - CFAR family except OSGO - CFAR that handle all models successfully. For modified CA - CFAR family only modified GO - CFAR handle all models successfully and comparing with OSGO - CFAR the modified GO - CFAR need less hardware and processing time because it did not need sorting process that is essential for OSGO - CFAR. Therefore, the modified GO - CFAR is chosen to implement by using FPGA and another important feature in modified GO - CFAR algorithm that is parallel processing since the spike selection process is done at the same time with summing of samples process that make this algorithm much less in processing time from any other algorithm that work in the same environment. The FPGA chip that used to implement modified GO - CFAR algorithm need only three signals from the radar receiver to mach with the receiver circuit correctly which are time base clock signal period reset trigger signal and the pulse duration time. Therefore, the FPGA chip can work effectively with almost any radar receiver system

مسيطر السرعة المثالي بالاعتماد على المتجه المسيطر لمسوق محرك التيار المستمر عديم الفرش == Optimal Speed Controller Based On Vector Controlled For A Brushless DC Motor Drive

Author name: مصطفى بشار عبد الملك
Supervisor name: تركي كحيوش حسن
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: اصبحت محركات التيار المستمر عديمة الفرش شائعة جدا في الكثير من المجالات مثل في الصناعة والتطبيقات المنزلية؛ وذلك يعود الى مميزاتها العديدة على محركات التيار المستمر ذوات الفرش والمحركات الحثية؛ مثل كفائتها العالية, كثافة قدرتها العالية وحجمها الصغيرنسب | Brushless DC (BLDC) motors have become very popular in various fields such as in industry or home appliances; and that is due to their many advantages over the brushed DC motors and the induction motors such as their higher efficiency, high power density and respectively low volume. The traditional and most popular way to drive BLDC motor is by using six - step or trapezoidal technique. This technique however has several problems such as high torque ripple and high distortion in the currents. This thesis presents a BLDC motor drive system where the performance of the motor is improved on various aspects. The first aspect is to improve the speed response by using particle swarm optimization (PSO) technique to find the optimal parameters of the speed controller. The second aspect is to reduce the torque ripple associated with the traditional driving technique and also improve the dynamic response of the motor by using vector or field - oriented control to drive the motor. The third aspect is improving the total harmonic distortion (THD) of the voltages and currents by using multilevel inverter. The last aspect is driving the motor in sensorless operation for reduced cost and for applications where speed and position sensors cannot be used; this operation uses a flux - linkage observer with a phase - locked loop (PLL) structure to estimate the position and speed of the rotor. The control methods are modeled using MATLAB/Simulink program and the results show that the proposed systems has significant improvement in performance as compared with the traditional technique in terms of speed response, torque ripple and THD of the voltages and currents

التاثيرات الكهربائية والبصرية لتشويب اغشية اوكسيد الخارصين (ZnO) المكونة لمتحسس الاشعة فوق البنفسجية بالفضة == Electrical And Optical Effects Of Ag Doped ZnO Thin Film Based MSM UV Photodetectors

Author name: محمد وسام ناجي
Supervisor name: منير عبود هاشم | غصون محسن علي
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: يستخدم اوكسيد الخارصين (ZnO) لكشف الاشعة فوق البنفسجية وذلك لكبر فجوة الطاقة وكبر طاقة اثارة الربط لهذا الشبه موصل. اوكسيد الخارصين كذلك يمتلك سرعة اشباع عالية وفولتية انهيار عالية. في هذا العمل تم تصنيع متحسس اشعة فوق بنفسجية نوع (معدن - شبه موصل - معدن) با | Zinc Oxide (ZnO) has been commonly used for ultraviolet detection due to large band gap and excition binding energy. ZnO has high breakdown electrical field, also has a much larger saturation velocity. In this work three ultraviolet Metal Semiconductor Metal (MSM) photodetectors were fabricated, based on ZnO and Silver (Ag) doped Zinc Oxide (SZO) with (2% and 4 % doping ratios) thin films. The technique used to prepare the thin films was sol - gel and spin coating technique by using Si (100) p - type. Silver interdigitated (IDT) electrodes were deposited on the films by a vacuum coating deposition technique to form the three devices.The electrical properties for the fabricated photodetectors (PDs) were studied using Semiconductor Characterization System (SCS) at room temperature ( 27 C^o). The applied voltage was in the range of ( - 5 to 5) V.The SEM images showed a non - uniform distribution of the Ag dopants, these dopants formed clusters and these clusters increased as the amount of Ag dopants increased. The mobility, carrier concentration, and roughness for the SZO films increased when compared to undoped film. The optical bandgap and the transmittance are decreased when the doping ratio is increased. The saturation current (I - S) was decreased by a factor of 4, and 12 for the devices based on Ag doped ZnO (with 2% and 4 % doping ratios) thin films, respectively. The sensitivity was significantly increased with increasing the doping ratio. This enhancement attributed to the roughness of the Ag dopants (clusters). The detectivity was increased for the devices based on SZO films. The high detectivity with low saturation current made the devices based on SZO films suitable for optoelectronic applications and integrated circuits. From the experimental data and analysis, it was found that the PD with ZnO : Ag 4 % doping ratio has higher responsivity and gain of 0.523 A/W and 257 , respectively. This is confirmed by thin film and device characterization which makes this PD suitable for UV detection purposes.

النمذجة التحليلة لاداء الثنائي الضوئي p - i - n == Analytical Modeling Of A P - I - N Photodiode Performance

Author name: محمد شهاب احمد
Supervisor name: منیر عبود ھاشم
Degree: Master
Language: English
University location: Baghdad
First pages:
Abstract: The analysis of a silicon p - i - n photodiode with a uniform doping concentration in each layer is presented. The theoretical treatment aims at investigating the device operation and performance to obtain optimum values of photodiode parameters when operates as a photodetector.Large bandwidth, good responsivity, device speed and quantum efficiency at wavelength of interest, combined with its low operating voltage and capability, make this diode promising for optoelectronic receiver circuits for use in optical communication systems and computer interconnections.High speed silicon p - i - n photodiode which operate at 700 nm wavelength is reported. By using a reverse bias voltage to control electric field, a high quantum efficiency of 80% is attained corresponding to bandwidth of 6.5 GHz at depletion width of 5.36 ?m and biasing voltage of 27.5 V. The minimum detectable incident light signal power is 3.9 ?W corresponding to signal to noise ratio of 6.5*104. The results show that, there is trade - off between quantum efficiency and bandwidth. Since the intrinsic layer of a p - i - n photodiode can be made with a lightly doping concentration, a p - ? - n photodiode is also treated mathematically with a software tool, and the results obtained are very close to those for a p - i - n photodiode. The results are achieved with the aid of MATLAB programming tool version 8.1.0.604 (R2013a).
1 ... 40 41 42 43 44 ... 79