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Band sharing and satellite diversity techniques for CDMAAttia, Tarek January 2001 (has links)
High levels of interference between satellite constellation systems, fading and shadowing are a major problem for the successful performance of communication systems using the allocated L/S frequency bands for Non-Geostationary Earth Orbit (NGEO) satellites. As free spectrum is nonexistent, new systems wishing to operate in this band must co-exist with other users, both satellite and terrestrial. This research is mainly concerned with two subjects. Firstly, band sharing between different systems Code Division Multiple Access (CDMA) and Time Division Multiple Access (TDMA) has been evaluated for maximizing capacity and optimising efficiency of using the spectrum available. For the case of widened channel bandwidth of the CDMA channel, the overlapping was tested under different degrees of channel overlap and different orders of filters. The best result shows that at the optimum degree of channel overlap, capacity increases by up to 21%. For the case of fixed channel bandwidth, the optimum overlapping between CDMA systems depends on the filtering Roll-off factor and achieves an improvement of the spectrum efficiency of up to 13.4%. Also, for a number of narrowband signal users sharing a CDMA channel, the best location of narrowband signals to share spectrum with a CDMA system was found to be at the edge of the CDMA channel. Simulation models have been constructed and developed which show the combination of DS- CDMA techniques, forward error correction (FEC) code techniques and satellite diversity with Rake receiver for improving performance of interference, fading and shadowing under different environments. Voice activity factor has been considered to reduce the effect of multiple access interference (MAI). The results have shown that satellite diversity has a significant effect on the system performance and satellite diversity gain achieves an improvement up to 6dB. Further improvements have been achieved by including concatenated codes to provide different BER for different services. Sharing the frequency band between a number of Low Earth Orbit (LEO) satellite constellation systems is feasible and very useful but only for a limited number of LEOS satellite CDMA based constellations. Furthermore, satellite diversity is an essential factor to achieve a satisfactory level of service availability, especially for urban and suburban environments.
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Efficient signal enhancement schemes for adaptive antenna arrays in DS-CDMA systemsKim, Kyungseok January 2001 (has links)
Adaptive antenna array technology will undoubtedly form a vital part of third generation cellular systems owing to not only confining the radiated energy associated with a mobile to a small volume on the downlink but also reducing the interference due to cochannel users on the uplink. The objective of this thesis is to develop signal enhancement schemes for adaptive antenna arrays for the purpose of enhancing the quality and capacity of direct sequence code division multiple access (DS-CDMA) systems. Firstly, The signal enhancement scheme using a real symmetric array covariance matrix (RSACM) method was proposed. This proposed scheme is composed of a unitary and persymmetric transformation methods. A real symmetric array covariance matrix has the same Toeplitz-plus-Hankel matrix structure that is produced by almost total noiseless data sequence. The second proposed signal enhancement scheme consists of the rotation of signal subspace (RSS) and Toeplitz matrix approximation (TMA) methods. This proposed scheme improved the system performance by reducing the interference- plus-noise effect from the complex array covariance matrix of the pre-correlation received signal vector. The third proposed signal enhancement scheme is a modified linear signal estimator (MLSE) which involves the rank N approximation by reducing total noise eigenvalues (RANE) and TMA methods. The aim of this proposed scheme is to improve the system performance by effectively reducing the interference-plus-noise effect from the post-correlation received signal. Secondly, the computational complexity and the performance for all proposed signal enhancement schemes in this thesis are investigated and compared. The signal enhancement scheme using the RSS+TMA and MLSE methods was also proposed for a multi-rate and multicell DS-CDMA systems. The relative other-cell interference factor was analysed for a multicell condition. Finally, the performance of all proposed signal enhancement schemes is shown to be much better than that of no signal enhancement method under a single cell, multicell, single rate, and multirate conditions.
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Kodifikace práva ve Francii za 1. císařství / Codification of law in France under the First EmpireVavříček, Martin January 2011 (has links)
Codification of law in France under the First Empire The purpose of my thesis is to analyze genesis of preparation of six codes in France, to explain all influences and to show importance of this codification for the rest of the world. The scope of my thesis research is wider than just a description of codification works between years 1804-1815. The first part of this work explores the basis for codification. Sources of law, roman law, natural law, age of enlightenment, Declaration of the Rights and of the Citizens and legislative procedure under the First empire. The second part is composed of five chapters. Chapter one describes French Civil code promulgated in 1804. This chapter is composed of following subchapters: genesis of codification between years 1789-1804, the major figures of codification, systematics, related laws, selected paragraphs of Civil code and language quality. Chapter two is about Code of civil procedure (Code de procedure civile, 1806). It is composed of three subchapters: genesis, systematic and characteristics of this code. Chapter three describes Commercial Code (Code de commerce, 1807). This chapter includes genesis of commercial law from 16th century. The rest subchapters analyze genesis, systematic and characteristics of this codification. Chapter four is composed of...
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Kodewisseling tussen Afrikaans en Engels as instrument vir effektiewe kommunikasie : 'n sosiolinguistiese ondersoekLawrence, Donovan Charles. 13 August 2012 (has links)
M.A. / Although codeswitching as an area of sociolinguistic behaviour has become increasingly prevalent in the public and social life of a multilinguistic and multicultural South Africa, it remains an unexplored area. To many codeswitching is something impure which shows the lack of understanding of this phenomenon. Since 1993 students and lecturers at the Sohnge College of Education have been exposed to a new language contact situation between Afrikaans and English. The alternating between Afrikaans and English within the same conversation (codeswitching) is an option that has been taken in an effort to facilitate the communication process. The aim of this study is to indicate the effectiveness of codeswitching as a means of communication in the language use of lecturers at the Sohnge College of Education. A group interview had been conducted in order to establish what the lecturers' ideas and experiences of codeswitching are. Recordings of lectures, tutorials and meetings were made to ascertain when, where and why lecturers codeswitch. The data was analysed with regard to social motivations and linguistic structures. For this the models of Carol Myers- Scotton, one of the leading researchers in the field of codeswitching, were used. These are the Markedness Model (for establishing the social motivations) and the Matrix Language Frame Model (for analysing the linguistic constraints). Given the fact that this study is the first to investigate codeswitching between Afrikaans and English by using the models of Myers—Scotton, one can only hope that this first effort will cast some light on this common and yet unexplored phenomenon of codeswitching between Afrikaans and English.
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Analysis of Wideband Code Division Multiple Access (WCDMA) system with co-channel interferenceArgyros, Andreas 09 1900 (has links)
Approved for public release; distribution is unlimited. / The Wideband Code Division Multiple Access is a third generation air interface, initiated in European Union
research projects at the start of the 1990s. The standard emerged by the end of 1999 as part of the 3GPP
standardization process. It was designed to support multiple simultaneous services with high quality services
through an increased data rate.
This research examines the properties and parameters of the WCDMA system to determine the feasibility
of intercepting and exploiting this technology with known assets. It explores this possibility by looking at link
analysis, adaptive antennas and co-channel interference canceling techniques to determine if the interception of
WCDMA signals is possible. / Lieutenant Junior Grade, Hellenic Navy
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The automatic generation of code generators with particular reference to cobolBulmer, Allan Roy 15 March 2013 (has links)
No description available.
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JQuery - a tool for combining query results and a framework for building code perspectivesMarkle, Lloyd 11 1900 (has links)
In this dissertation we identify two problems with current integrated development
environments (IDEs) and present JQuery as a tool to address these issues.
The first problem is that IDE views answer low level questions and do not provide a mechanism to combine results to answer complex higher level questions. Even relatively simple questions force the developers to mentally combine results from different views.
The second problem is that IDEs do not provide an easy way to create perspectives on project specific concerns such as naming conventions or annotations. Most IDEs do offer support for creating custom perspectives but the effort required to create a perspective is considerably more than the benefit a custom perspective provides.
JQuery is an Eclipse plugin which generates code views using an expressive query language. We have redesigned JQuery to support a number of new user interface (UI) features and add a more flexible architecture with better support for extending the UI.
To address the first problem, we have added multiple views to JQuery where each view supports drag and drop of results, selection linking, and regular expression search. These features enable a user to combine results from different views to answer more complex higher level questions. To address the second problem, we can leverage the fact that JQuery is built on an expressive query language. Through this query language we are able to define project specific concerns such as naming conventions or annotations and then create views and perspectives for these concerns through the JQuery UI. / Science, Faculty of / Computer Science, Department of / Graduate
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The bilingual assessment of cognitive abilities in French and EnglishLacroix, Serge 11 1900 (has links)
In this study the role that language plays in the expression of intelligence, bilingualism, and the process of assessing selected cognitive abilities was explored. The primary purpose of the study was to determine if individuals who are allowed to move from one language to another when they provide responses to test items produce results that are different than those obtained by bilingual examinees assessed in one language only. The results indicate that the Experimental Group obtained significantly higher results than the Control Group on all the tests and subtests used. The Experimental Group code-switched more frequently and the examiners only code-switched with that group. The frequency of the code-switching behaviours explains, in great part, all the differences noted in the results as very few other sources of differences were identified, even when groups were compared on sex, first language and relative proficiency in French and in English. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate
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Codeswitching in the multilingual mindHilderman, Dustin 22 December 2017 (has links)
The very existence of intra-word codeswitching—of the type [w ML1 + ML2]; *[eat]eng + [-iendo]Spanish —has long been a point of contention in the language mixing literature (Poplack, 1980; Myers-Scotton, 1992; MacSwan, 2005). However, recent work by Alexiadou et al (2015) and Grimstad, Lohndal & Afarli (2014) has documented a number of empirical examples of such codeswitching in an American community of Heritage Norwegian-English speakers—crucially, in these examples, the lexical elements are English lexical roots and produced using English phonological rules but the suffix (i.e. morphology) attached to the lexical items is syntactically Norwegian—a clear and unambiguous example of intra-word codeswitching. These data will be the focus of investigation into intra-word codeswitching.
MacSwan (2005) has argued that intra-word codeswitching is prohibited due to the inability of the human computational system to merge hierarchically ordered phonological systems from two or more languages; a prohibition characterized in his PF Disjunction Theorem. More recently, Alexiadou et al., (2015); Grimstad, Lohndal & Afarli, (2014) have exploited a model of Distributed Morphology to challenge the PF disjunction theorem and the ban on intra-word codeswitching it entails. A central goal of this thesis will be to compare, contrast and evaluate these two models of language mixing. It will be argued that this prohibition of intra-word language mixing may be overcome by appealing to a cognitive processes perspective (Sharwood-Smith & Truscott, 2014).
A MOGUL processing prospective (Sharwood-Smith & Truscott, 2014) will be used to build upon previous approaches to language mixing in order to account for intra-word codeswitching. The modular architecture adopted by MOGUL allows for a molecular view of a lexical item; each module (i.e. phonological module, syntax module, conceptual module) produces a representation for a given form which is then interfaced to neighboring modules; the result is a chain of representations (i.e. PS + SS + CS) which constitutes a lexical item. Additionally, MOGUL incorporates several extra-linguistic cognitive mechanisms which play a role in language mixing. Of particular interest are the notions of goals and cognitive context. Following Sharwood-smith & Truscott (2016), goals are the central motivators for speech and action while cognitive context is taken to be the mentally internalized representation of an individual’s current environment (Sharwood-Smith & Truscott, 2014) as well as representing various intentions, perspectives, opinions, etc., an individual has regarding their environment (Van Dijk, 1997).
To situate intra-word codeswitching into a MOGUL framework, much of MacSwan’s Minimalist account will be adopted, (i.e. codeswitching is accounted for via the union of grammar X and grammar Y; formally: {Gx ᴜ Gy}) while rejecting the PF Disjunction Theorem and, instead, adopting elements of Distributed Morphology (i.e. late insertion). It will be argued that cognitive context configures various executive control process (i.e. bilingual mode) to allow for the union of phonological systems between Lx and Ly. This analysis builds upon a larger body of language mixing research by synthesizing a Minimalist account of codeswitching with a cognitive processing framework to account for intra-word codeswitching; the MOGUL framework allows for these disparate elements to be synthesized. / Graduate
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BLIND EQUALIZATION WITH LDPC CODE: TO QUASIERROR FREE TRANSMISSIONS IN TELEMETRYBlanc, Grégory, Skrzypczak, Alexandre, Pierozak, Jean-Guy 11 1900 (has links)
In a telemetry system, it has been frequently proved that multipath channels and transmission
noise are the most critical sources of distortion. While equalization allows a strong limitation of
the multipath effects, the noise impact can be efficiently reduced if forward error correction is
used. This paper proves that the combination of blind equalization and a powerful FEC like
LDPC strongly improves bit error rates for the SOQPSK modulation. We also prove that a LDPC
code is able to fully correct the residual errors that may persist at the equalizer output. In other
terms, the combination of equalization and LDPC code enables quasi-error free transmissions in
various channel scenarios that represent the various phases of a telemetry mission.
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