البحث — المستودع الرقمي العراقي

المستخلص: 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).

الصفحات الاولى:

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الاتصالات

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: وائل عبد الحسن هادي

اسم المؤلف: نبيل احمد مصدق

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

المستخلص: 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.

الصفحات الاولى:

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: منال حمادي جاسم

اسم المؤلف: تمارا زهير فاضل

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

المستخلص: 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.

الصفحات الاولى:

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: علي يوسف فتاح

اسم المؤلف: علاء عبد الزهرة جعفر

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

المستخلص: 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.

الصفحات الاولى:

الكلمات الدلالية:

Pattern Recognition
RAM - based Weightless Neural Network

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: محمود حمزة المفرجي

اسم المؤلف: سهاد قاسم غلام حسين حداد

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

المستخلص: 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.

الصفحات الاولى:

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: ثائرة زكريا الطيار

اسم المؤلف: نور احمد سلمان