M.Ing. (Electrical and Electronic Engineering) / In this study, the problem of correcting burst of adjacent deletions by adapting product codes was investigated. The first step in any digital transmission is to establish synchronization between the sending and receiving nodes. This initial synchronization ensures that the receiver samples the information bits at the correct interval. Unfortunately synchronization is not guaranteed to last for the entire duration of data transmission. Though synchronization errors rarely occur, it has disastrous effects at the receiving end of transmission. These synchronization errors are modelled as either insertions or deletions in the transmitted data. In the best case scenario, these errors are restricted to single bit errors. In the worst case scenario, these errors lead to bursts of bits being incorrect. If these synchronization errors are not detected and corrected, it can cause a shift in the transmitted sequence which in turn leads to loss of synchronization. When a signal is subjected to synchronization errors it is difficult accurately recover the original data signal. In addition to the loss of synchronization, the information transmitted over the channel is also subjected to noise. This noise in the channel causes inversion errors within the signal. The objective of this dissertation is to investigate if an error correction scheme can be designed that has the ability to detect and correct adjacent bursts of deletions and random inversion errors. This error correction scheme needed to make use of a product code matrix structure. This product matrix needed to incorporate both an error correction and synchronization technique. The chosen error correcting techniques were Hamming and Reed-Solomon codes. The chosen synchronization techniques for this project were the marker technique or an adaptation of the Hamming code technique. In order to find an effective model, combinations of these models were simulated and compared. From the research obtained and analyzed in this document it was found that, depending on the desired performance, complexity and code rate, an error correction scheme can be used in the efficient correction of bursts of adjacent deletions by adapting product codes.

Orientador: Rubén Augusto Romero Lázaro / Banca: Anna Diva Plasencia Lotufo / Banca: Marcos Julio Rider Flores / Resumo: Neste trabalho é realizada uma análise teórica, a formulação conceitual e a implementação computacional de um algoritmo de vizinhança variável aplicado ao problema de planejamento a longo prazo de sistemas de transmissão de energia elétrica. O problema de planejamento de sistemas de transmissão é um problema muito complexo de resolver porque o modelo matemático é um problema de programação não linear inteiro misto. Por outro lado, a metaheurística de vizinhança variável é uma técnica de otimização que provou excelente desempenho na resolução de problemas complexos no campo da pesquisa operacional. Assim, neste trabalho é desenvolvido um algoritmo de vizinhança variável para o problema de planejamento de sistemas de transmissão. Um conceito importante na implementação desse algoritmo é a definição de vizinhança em relação a caminhos e a técnica de redução do tamanho da vizinhança. Testes realizados mostraram um excelente desempenho do algoritmo VNS, encontrando as melhores soluções conhecidas e mostradas na literatura especializada / Abstract: In this work a theoretical analysis is carried through, the conceptual formularization and the computational implementation of an applied algorithm of variable neighborhood to the problem of planning in the long run of systems of transmission of electric energy. The problem of planning of transmission systems is a very complex problem from solve because the mathematical model is a programming problem not linear. On the other hand, the metaheuristic of variable neighborhood is one technique of optimization that proved excellent performance in the resolution of complex problems in the field of the operational research. Thus, in this work is developed an algorithm of variable neighborhood for the problem of planning of transmission systems. An important concept in the implementation of this algorithm is the definition of neighborhood in relation the paths and the technique of reduction of the size of the neighborhood. Tests carried through had shown to an excellent performance of algorithm VNS, finding the best solutions known and shown in specialized literature / Mestre

Promoting healthcare and wellbeing requires the dedication of a multi-tiered health service delivery system, which is comprised of specialists, medical doctors and nurses. A holistic view to a patient care perspective involves emotional, mental and physical healthcare needs, in which caring is understood as the essence of nursing. Properly and efficiently capturing and managing nursing knowledge is essential to advocating health promotion and illness prevention. This thesis proposes a document-indexing framework for automating classification of nursing knowledge based on nursing theory and practice model. The documents defining the numerous categories in nursing care model are structured with the help of expert nurse practitioners and professionals. These documents are indexed and used as a benchmark for the process of automatic mapping of each expression in the assessment form of a patient to the corresponding category in the nursing theory model. As an illustration of the proposed methodology, a prototype application is developed using the Latent Semantic Indexing (LSI) technique. The prototype application is tested in a nursing practice environment to validate the accuracy of the proposed algorithm. The simulation results are also compared with an application using Lucene indexing technique that internally uses modified vector space model for indexing. The result comparison showed that the LSI strategy gives 87.5% accurate results compared to the Lucene indexing technique that gives 80% accuracy. Both indexing methods maintain 100% consistency in the results. / by Sucharita Vijay Chichanikar. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Next, we investigate several models of TRC including the discrete memoryless TRC, the Gaussian TRC and the bandlimited Gaussian TRC, and prove an outer bound on the capacity region of each of the TRC models. In particular, the outer bound on the capacity region of the bandlimited Gaussian TRC is a theoretical outer bound on the capacity region achievable by physical-layer network coding (PNC). Furthermore, we model a cellular relay network consisting of multiple users, multiple relays and multiple base stations as a collection of two-node point-to-point systems and three-node networks, where each two-node point-to-point system consists of two bandlimited Gaussian channels and each three-node network consists of a bandlimited Gaussian TRC. We obtain performance bounds of PNC on the cellular relay network by simulation and our simulation results show that the average maximum equal-rate throughput over all users under every PNC strategy investigated is generally worse than the average equal-rate throughput over all users under some routing strategy. This is possibly due to larger interference among the nodes under the PNC strategies compared with the routing strategy. / Our investigation of wireless relay networks begins by studying the two-way relay channel (TRC), in which a user and a base station exchange their messages with the help of a middle relay. We model the TRC as a three-node point-to-point relay network and propose practical symbol-level network coding schemes for the three-node network. We obtain several rate regions achievable by the network coding schemes and show that the use of symbol-level network coding rather than routing alone always enlarges the achievable rate region. Inparticular, the use of symbol-level network coding always increases the maximum equal-rate throughput. Furthermore, we model a cellular relay network consisting of multiple users, multiple relays and multiple base stations as a collection of two-node point-to-point systems and three-node point-to-point relay networks where each point-to-point channel is modeled as a bandlimited Gaussian channel. We propose several practical symbol-level network coding schemes on the network and investigate the benefit of symbol-level network coding by simulation. Our simulation results show that the use of symbol-level network coding rather than routing alone increases the average maximum equal-rate throughput over all users. / Fong, Lik Hang Silas. / Adviser: Yeung, Wai-Ho Raymond. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 267-270). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Wan Wai Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 77-[80]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Wireless Multimedia System --- p.1 / Chapter 1.2 --- Motivation of this thesis --- p.2 / Chapter 1.3 --- The theme of this thesis --- p.4 / Chapter 1.3.1 --- System Model and Assumptions --- p.4 / Chapter 1.3.2 --- Outline of the thesis --- p.5 / Chapter 2 --- Overview of TDMA/FDMA Digital Cellular Systems --- p.7 / Chapter 2.1 --- The Cellular Concept --- p.7 / Chapter 2.2 --- Channel Assignment Strategies --- p.9 / Chapter 2.2.1 --- Fixed Channel Assignment --- p.9 / Chapter 2.2.2 --- Dynamic Channel Assignment --- p.9 / Chapter 2.3 --- Multiple Access Techniques --- p.10 / Chapter 2.3.1 --- Introduction to Multiple Access --- p.10 / Chapter 2.3.2 --- Frequency Division Multiple Access - FDMA --- p.11 / Chapter 2.3.3 --- Time Division Multiple Access - TDMA --- p.12 / Chapter 2.4 --- A TDMA/FDMA System - GSM --- p.13 / Chapter 2.4.1 --- Global System for Mobile --- p.13 / Chapter 2.4.2 --- GSM radio subsystem --- p.13 / Chapter 3 --- Multi-rate Data in TDMA/FDMA Digital Cellular Systems --- p.17 / Chapter 3.1 --- Incorporation of Multimedia Data --- p.17 / Chapter 3.2 --- A Global Optimal Strategy --- p.19 / Chapter 3.2.1 --- Channel Rearrangement --- p.19 / Chapter 3.2.2 --- Analytical Performance Analysis of a Special Case --- p.21 / Chapter 3.2.3 --- Numerical Results --- p.24 / Chapter 3.2.4 --- Issues in Channel Rearrangement --- p.25 / Chapter 4 --- Multiple Slots Allocations --- p.26 / Chapter 4.1 --- Introduction --- p.26 / Chapter 4.2 --- No-Split Algorithm --- p.27 / Chapter 4.2.1 --- No-Split Algorithm --- p.27 / Chapter 4.2.2 --- Pros and Cons --- p.28 / Chapter 4.3 --- Best Fit Algorithm --- p.29 / Chapter 4.3.1 --- Best Fit Algorithm --- p.29 / Chapter 4.3.2 --- Optimization --- p.31 / Chapter 4.3.3 --- Pros and Cons --- p.32 / Chapter 4.4 --- Comparison of the two algorithms --- p.32 / Chapter 5 --- Buddy Algorithm --- p.37 / Chapter 5.1 --- Introduction --- p.37 / Chapter 5.2 --- Buddy System in Memory Management --- p.38 / Chapter 5.3 --- Buddy Algorithm --- p.40 / Chapter 5.3.1 --- Adaptation in slot allocation --- p.40 / Chapter 5.3.2 --- Data structure --- p.40 / Chapter 5.3.3 --- Slot allocation --- p.40 / Chapter 5.3.4 --- Slot deallocation --- p.44 / Chapter 5.4 --- Inference Property --- p.45 / Chapter 5.4.1 --- Proof of the Inference Property --- p.47 / Chapter 5.5 --- Pros and Cons --- p.49 / Chapter 6 --- Performance Study --- p.51 / Chapter 6.1 --- Introduction --- p.51 / Chapter 6.2 --- Fixed Channel Assignment --- p.52 / Chapter 6.2.1 --- System Parameters --- p.52 / Chapter 6.2.2 --- Simulation Results --- p.53 / Chapter 6.3 --- Dynmaic Channel Assignment --- p.55 / Chapter 6.3.1 --- System Parameters --- p.55 / Chapter 6.3.2 --- Simulation Results --- p.56 / Chapter 7 --- A Case Study - H.263 Video Coding --- p.59 / Chapter 7.1 --- CCITT H.263 Image Compression --- p.59 / Chapter 7.2 --- On a GSM Network --- p.60 / Chapter 8 --- Conclusion --- p.63 / Chapter A --- A General Data + Voice System with Channel Rearrangement --- p.65 / Chapter A.1 --- System Model --- p.65 / Chapter A.2 --- Markovian Analysis --- p.66 / Chapter B --- NP-Completeness Proof of the Best Fit Algorithm --- p.69 / Chapter B.1 --- CONSTRAINT SUBSET-SUM Problem --- p.69 / Chapter B.2 --- BEST-FIT Problem --- p.72 / Chapter C --- Proof of Proposition 5.2 --- p.74 / Chapter C.1 --- Upper Bound on Demand Advancement --- p.74 / Chapter C.2 --- Proof of Proposition 5.2 --- p.75 / Bibliography --- p.77

"Recently the Internet has been increasingly used for multi-party applications like video-conferencing, video-on-demand and shared white-boards. Multicast extensions to IP to support multi-party applications are best effort, often resulting in packet loss within the network. Since some multicast applications can not tolerate packet loss, most of the existing reliable multicast schemes recover each and every lost packet. However, multimedia applications can tolerate a certain amount of packet loss and are sensitive to long recovery delays. We propose a new loss recovery technique that selectively repairs lost packets based upon the amount of packet loss and delay expected for the repair. Our technique sends a special WAIT message down the multicast tree in the event a loss is detected in order to reduce the number of retransmission requests. We also propose an efficient sender initiated multicast trace-route mechanism for determining the multicast topology and a mechanism to deliver the topology information to the multicast session participants. We evaluate our proposed technique using an event driven network simulator, comparing it with two popular reliable multicast protocols, SRM and PGM. We conclude that our proposed WAIT protocol can reduce the overhead on a multicast session as well as improve the average end-to-end latency of the session."

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography : leaf 188. / M.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 71. / by David Mark Ryter. / B.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Rene Leonardo Cruz. / M.S.