8393 research outputs found
Sort by
Use of Orthogonal Frequency Division Multiple Access (OFDMA) In cellular systems
No full textThe aim of this project is to design an OFDMA cellular radio system and emphasis it‟s
suitability for broadband wireless access in metropolitan areas.Recently there has been an increase in demand for digital services provided over cellular radio
system. wireless revolution, or more correctly evolution, is in full swing worldwide. In our thesis
we present a short history of mobile wireless telephony with an emphasis on the relevant air
interface technologies. The thesis cover a simulation of an orthogonal frequency division multi
access (OFDMA) cellular radio system using Matlab M-files .the transmitter and receiver
accommodate orthogonal divison multiplexing (OFDM) as a modulation scheme the obtained
result cover performance study of the system and it‟s satisfaction to the intended objective
POWER ELECTRONIC INVERTER CIRCUITS
No full textThis project proposes a microcontroller-based single and three phase inverter designs
using Pulse Width Modulation technology (PWM). This technique is beneficial for reducing
harmonics which in turn reduces the cost and size of the circuit.The word ‘inverter’ in the context of power-electronics denotes a class of power
conversion (or power conditioning) circuits that operates from a DC voltage source or a DC
current source and converts it into AC voltage or current. The ‘inverter’ does reverse of what
AC-to-DC ‘converter’ does. Even though input to an inverter circuit is a DC source, it is
common to have this DC derived from an AC source such as utility AC supply. Thus, for
example, the primary source of input power may be utility AC voltage supply that is ‘converted’
to DC by an AC to DC converter and then ‘inverted’ back to AC using an inverter. Here, the
final AC output may be of a different frequency and magnitude than the input AC of the utility
supply.
Power-electronics inverters vary in their types and applications. They are used in
uninterruptable power supplies (UPSs), high voltage DC transmission, solar modules and
induction heating. However, principle remains the same no matter what size the power inverter
happens to be.
This project proposes a microcontroller-based single and three phase inverter designs
using Pulse Width Modulation technology (PWM). This technique is beneficial for reducing
harmonics which in turn reduces the cost and size of the circuit.
The project goals were partially met. The design was checked using computer simulation.
The hardware implementation of the simple H-bridge square wave inverter was achieved
successfully as well as the PWM switching signal of the single phase inverter. However,
problems were encountered in changing the frequency of this sinusoidal PWM signal and others
were appeared in the driving circuitry of the three phase inverter. Solutions for those problem
and further improvements of the design were suggested to be implemented in the future
OPTICAL CHARACTER AND WORD RECOGNITION OF ARABIC PRINTED TEXT
No full textthe project objective to:Prepare a general study about the OCR field, Convey the standard methods used in OCR systems and design others that suit the Arabic language and Design an Arabic OCR system that will be able to recognize an Arabic printed text.The Optical Character Recognition (OCR) is defined as the process of automatic conversion of scanned images of machine printed or handwritten documents into a format that a computer can process. Many OCR systems are well developed and implemented for different languages such as English and Japanese. However, Arabic suffers from the lack of research. This thesis represents a design of an Arabic OCR system. It is designed to recognize a range of sizes between 18 to 72 points of Times New Roman font. Basically, a set of unique and robust features are selected to define each Arabic letter. These features are extracted from templates images and saved for a later comparison. A proposed algorithm is used to segment the Arabic text into letters. These letters are then passed to a feature extraction stage which extracts those pre-defined features from the letter. The extracted features and the saved ones are compared together to recognize the letters. A recognized letter is written in a text file
Electrical Machine Testing and Control Using Matlab Simulink
No full textThis project describes the MATLAB/Simulink realization of Electrical machines laboratory.This project describes the MATLAB/Simulink realization of Electrical machines laboratory. The DC motor Speed control methods, namely field resistance, armature voltage and armature resistance Control methods, and induction motor experiment test these simulation techniques are developed to support and enhance undergraduate electric of machine course laboratory work. A MATLAB/Simulink implementation of three induction motor tests, namely dc, no-load and blocked-rotor tests performed to identify equivalent circuit parameters. The proposed tests have been successfully modeled and simulated for a given machines and result is found in numerical and graphical farms when is satisfactory , simulation tools must be developed for induction motor experiments to serve as useful preparatory exercises before students come to the laboratory
IP Based Multimedia Services in Mobile Communications
No full textThis project is about the IMS system and SIP protocol also aims to
develop client/server java application and VOIP call. All applications are
implemented using the SDS simulator which is a trademark of ericsson company.
In the client/server application, client application which is installed in a personal
computer sends a message to the SIP application sever (SIP AS) (main component in
the SDS) then SIP AS sends a message to the client.
VOIP call application is implemented between two personal computers in a peer-topeer
network.There is a growing interest, both in the Internet and in the telecommunication
industries, in multimedia communication services. An increasing number of Internet
users who used to just surf the web or send emails are now becoming addicted to
services such as Instant Messaging (IM), online gaming, and voice and video on the
Net. These are examples of multimedia communication services delivered over the
Internet that are enabled by the Session Initiation Protocol (SIP) in conjunction with
other protocols.
The third generation of cellular system (3G) comes with new concept called IP
Multimedia subsystem (IMS) which is a key component in 3G architecture that aims
to offer Internet services everywhere and at any time using the same technologies that
used in the Internet (e.g. SIP protocol).
This project aims to study in general, the IMS system and SIP protocol also aims to
develop client/server java application and VOIP call. All applications are
implemented using the SDS simulator which is a trademark of ericsson company.
In the client/server application, client application which is installed in a personal
computer sends a message to the SIP application sever (SIP AS) (main component in
the SDS) then SIP AS sends a message to the client.
VOIP call application is implemented between two personal computers in a peer-topeer
network
Design And Implementation Of A Convolutional Encoder With Viterbi Decoder
No full textin this project Convolution encoding with
forward error correction Viterbi decoding was designed using trace back survivor
method with 16-bits trellis decoding.
The encoder and decoder designs were implemented on a Spartan 3AN FPGA Starter kit
(supported with XC3S700AN). Verilog language was used as a design entry. The system
was implemented on the kit using direct programming technique.Communication systems plays a major role in our lives specially that we live in the
informational revolution era, nowadays communication systems have reached extremely
high data rates; however it’s important to ensure that data reach destination correctly, for
this purpose channel coding used by adding redundancy bits to ensure that any error
occurs during transmission will be detected then corrected.
The use of re-transmission methods is not efficient and has large latency measure up to
the rising speed and data rates of communication links, the need of new techniques arise
here to be compatible with those systems, in this project Convolution encoding with
forward error correction Viterbi decoding was designed using trace back survivor
method with 16-bits trellis decoding.
The encoder and decoder designs were implemented on a Spartan 3AN FPGA Starter kit
(supported with XC3S700AN). Verilog language was used as a design entry. The system
was implemented on the kit using direct programming technique
Groundwater quality assessment using GIS, the case of Omdurman area, central Sudan
No full text11 pages (22-33) SJS 6(1) 2014Omdurman area, located west of the River Nile and White Nile is witnessing rapid urban expansion and land use change. Several axial irrigation schemes have developed accelerating the demand for water supply. This indeed, will place more pressure over the available groundwater resources. In order to measure any change of groundwater quality it is necessary to initially evaluate the background condition. This contribution employs a GIS- based Groundwater Quality Index (GQI) which synthesizes different variable water quality data (e.g. Cl-, Na+ and SO42+) by indexing them numerically relative to the World Health Organization (WHO) standards in order evaluate the overall groundwater quality in the study area. The GQI computed for Omdurman area indicated that the water quality is generally high (mean GQI = 90 out of 100) with respect to the WHO standards. Spatially the groundwater quality of the study area increased from the central area in the northeastern direction and decrease in the southeastern direction. This result was interpreted in terms of general groundwater flow, the recharge zone, geology and soil composition. Drilling at close distances and over pumping specially in the central region might create local variations of groundwater flow resulting in mixing of waters of different qualities deteriorating the quality of water in previously safe zones. This is expected due to the low hydraulic gradient (< 0.001) characterizing some parts of the study area as well as the minimum recharge far from the River Nile and the White Nile. المستخلص منطقة أمدرمان الواقعة غرب نهر النيل و النيل الابيض تشهد تمدد عمراني سريع و تغير في إستخدامات الارض. العديد من مشاريع الري المحوري نمت لتزيد في الطلب على المياه. الشيء الذي سيضع حتماَ عبأَ إضافياَ على المصادر المتوفرة للمياه. من الضروري تحديد نوعية المياه الاساسية لنتمكن من قياس التغير فيها. هذه الدراسة تستخدم مؤشر نوعية المياه الجوفية القائم على نظام المعلومات الجغرافية و الذي يعمل على تحليل و إختزال المتغيرات المختلفة لنوعية المياه عن طريق مقارنتها بالمعدلات القياسية لمنظمة الصحة العالمية وذلك لقياس نوعية المياه بصورة عامة في منطقة الدراسة. مؤشر نوعية المياه الجوفية لمنطقة أمدرمان أوضح أن المياه الجوفية بالمنطقة عالية الجودة )متوسط قيمة المؤشر = 09 من 099 ( بالنسبة لمقاييس منظمة الصحة العالمية. مكانيا تزداد جودة المياه الجوفية في إتجاه الشمال الشرقي من وسط منطقة الدراسة بينما تتناقص في إتجاه الجنوب الشرقي. هذه النتيجة فسرت على أساس الإتجاه العام لسريان المياه الجوفية، نطاق التغذية، جيولوجية المنطقة و نوعية التربة. الحفر على مسافات متقاربة و الضخ العالي خصوصا في المنطقة الوسطى قد يتسبب في تغيرات محلية في سريان المياه الجوفية ينتج عنها إختلاط مياه جوفية بنوعيات متباينة مما يغير في جودة المياه في المناطق الآمنة اصلا .ً هذا متوقع نسبة للميل الهايدروليكي المنخفض )أقل من 9.990 ( الذي يميز بعض المناطق بالإضافة للتغذية الضعيفة بعيداَ عن نهر النيل و النيل الأبيض
احصائية بنتائج الامتحانات التي عرضت علي مجلس الدراسات الاساسية والهندسية في اجتماع رقم 64-2014 كلية الدراسات العليا
No full textاحصائية بنتائج الامتحانات التي عرضت علي مجلس الدراسات الاساسية والهندسية في اجتماع رقم 64-2014 كلية الدراسات العلي
احصائية بنتائج الامتحانات التي عرضت علي مجلس الدراسات الطبية والصحية في اجتماع رقم 60-2014
No full textاحصائية بنتائج الامتحانات التي عرضت علي مجلس الدراسات الطبية والصحية في اجتماع رقم 60-201
تعديل تقديرالطالبة داليا محمد فرح فضل كلية الاداب
No full textتعديل تقديرالطالبة داليا محمد فرح فضل كلية الادا