البحث — المستودع الرقمي العراقي

المستخلص: مع ظهور قنوات الخفوت الترددية الاختيارية المتعددة المسارات. اصبح نظام تقسيم الشفرات المتعدد الوصول (CDMA) يعاني من التداخل بسبب تعدد المستخدمين (MUI) والتداخل بين الرموز(ISI) ولكن مع التصميم المناسب لنظام تقسيم الشفرات فانه يوفر التفريق الى مسارات متعدد | In the presence of frequency selective multipath fading channels, code division multiple access (CDMA) suffers from multiuser interference (MUI), and intersymbol interference (ISI), but when properly designed, it enjoys multipath diversity. Orthogonal frequency division multiple access (OFDMA) is MUI free, and it does not enable the available channel diversity without employing error control coding. But coded OFDMA may achieve lower diversity than a CDMA system employing the same error control codes. In this work, the advantages of OFDMA and CDMA are merged to minimize MUI effects, and also to make the maximum available diversity for every user possible, this system is called group orthogonal multicarrier CDMA (GO - MC - CDMA).In group orthogonal multicarrier CDMA (GO - MC - CDMA) scheme, groups of users share a set of subcarriers. By carefully choosing group subcarriers, there is aguarantees that every user transmits with maximum diversity. MUI is only present among users of the same group, and is suppressed via multiuser detection, which becomes practically feasible by assigning a small number of users per group. The performance of GO - MC - CDMA system is analyzed with 3M bits/sec in two paths frequency selective Rayleigh fading channel. Moreover, simulations are carried out to illustrate the performance of GO - MC - CDMA with number of active users, number of subcarriers, space diversity combining technique, types of spreading code, type of data detection techniques, finally, the effect of near - far problem.

العولمة واثارها في نقل التكنولوجيا في الوطن العربي == Globalization & Its Impacts Upon Transferring Technology In The Arab Nation

اسم المؤلف: وفاء محـمد عـزيـز الـرفيـعي

اسم المشرف: سمير عبود عباس الشمري

الموضوع العام: العلوم السياسية

السنة: 2006

الموضوع الدقيق: العلاقات الاقتصادية الدولية

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية - كلية العلوم السياسية

اللغة: العربية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: ان من الحقائق المؤكدة ان درجة التطور الاقتصادي والاجتماعي لاية دولة مرتبطة اساسا بدرجة تطور تلك الدولة تكنولوجيا، فالتكنولوجيا ذات اهمية حيوية في الحرب والسلم، وان الاعتبار التكنولوجية قد اصبحت تسيطر على البناء الاقتصادي لجميع الدول وتزداد هذه السيطرة مع | Our world is witnessing today a great acceleration of so many factors and incidents concerning spread of Globalization phenomena through all its mechanisms and organizations for the purpose of moving it from the regional aspect towards the universal aspect. In the time the Arab nations are suffering from lagging in the economical and social programs mainly due to lagging in the scientific and technological levels in comparison to the other countries in the civilized world. Globalization phenomena today is a comprehensive international concept and being adopted by well - known international organizations such as the UN, International Monetary Fund, National Bank for Building & Construction in addition to WTO. Upon the so - called basis the Arab nations should plan its strategy to interact with these incidents and using some of this phenomena’s mechanism precisely the part that help in transferring great deeds of the scientific technological revolution.This research is quite significance because it focuses on discovering and analyzing the tracks of this phenomenon in its all dimensions and mechanisms for the scientific and technological progress and results of the reflection over developing process in the Arab Nations. Thus multi - national companies are playing an eminent role in transferring and subjugating technology, in its international level, by applying in different projects worldwide. Objective of the research This research is aiming to achieve the following : 1 - Discovering and analyzing “Globalization” as an economical phenomena which is playing a considerable role in direct and indirect effect on the world economics including the Arab Nations.2 - Analyzing the phenomenon’s impact upon the scientific and technological sides. Meanwhile the multi - national companies are playing an extra role in promoting this process, as it is one of Globalization’s mechanism, reflexes on the technological development. 3 - The research is also aim to combine between development objective in the Arab Nations and means for achieving them.Research Hypothesis The research is based upon two hypotheses : A - Lagging of the Arab economy is mainly due to lagging in science and technology.B - Globalization, as phenomena, through its entire dimensions and mechanism, has influenced on the scientific and technological development in the Arab World.Methodology of the Research In order to achieve the research’s objective and hypothesis the researcher has performed different scientific research methods i.e. the descriptive and statistical analyzing methodology for discovering and analyzing the entity of Globalization including its mechanism as well as its impact over the technological development in the Arab Nations. Also using of the historical methodology to identify the historical background of creating and developing this global phenomenon. Analyzing the Scientific References The research has depended on scientific references, especially those related to Globalization and its mechanism and organizations, written by Arab and Iraqi authors and contemplator. In addition the research has made use of bunch of statistics and reports reveling the actual scientific and technological level in the Arab Nations. Previous studies also took part in this research such as independent researches and relevant scientific thesis written by specialized academic professors. Notably those references have enriched this research a lot. The frame of the Research In order to prove the research’s hypotheses and achieving its goals, the study has tackled the subject through a preface and three chapters consisting of nine topics plus the conclusions and recommendations;? Chapter One has tackled the theoretical background for the research regarding Globalization its mechanism and organizations connecting with technology. This chapter consists of three topics. The first topic has tackled the main concept for Globalization, the second tackled the mechanism and organizations of Globalization, while the third has tackled the relation between Globalization and technology.? Chapter Two has tackled the Arabic true technological level and development requirements. The first topic tackled the technological role in development process. The second topic took the Arabic technological reality while the third topic has studied the actual scientific and technological level of Arab Nations. ? Chapter Three has included Globalization influence upon the present and future of the Arab economy and technology. The first topic has studied the Globalization impacts upon Arab economical reality. The second topic included Globalization impacts upon Arab technological reality. While the third topic has taken the perspective horizons to limit globalization’s impacts upon Arab technology. The researcher has came into conclusions, from the contents and steps of her research, in order to give proper recommendations and present this study before other researchers and specialists in economy.