Дисертації з теми "Search of maximal codes"
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1
Кравчук, Володимир Вікторович. "Комплекс програм для визначення нероздільних завадостійких кодів". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/35023.
Повний текст джерелаАнотація:
Бакалаврський проєкт включає пояснювальну записку (55 с., 45 рис., 4 додатки).
В даній роботі досліджена тема завадостійкого кодування та пошуку максимальної кліки на графі. Розглянуто різні типи кодування, описана проблема аналітичної швидкості коду, проаналізовано алгоритм Брона-Кербоша для пошуку клік. На основі особливостей еквівалентних кодів та графа Хемінга, запропоновано способи покращення алгоритму для вирішення задачі пошуку максимального нероздільного завадостійкого коду. Було вирішено розробити комплекс програм, який допоможе спростити визначення та дослідження нероздільних завадостійких кодів.
Було сформовано конкретні вимоги та функціональність для комплексу, а саме: можливість пошуку максимальних нероздільних завадостійких кодів відповідно до заданих користувачем параметрів, зупинка роботи комплексу в певний момент часу із збереженням проміжних даних з якими працював алгоритм, завантаження збережених даних та продовження роботи після зупинки, можливість виконання різних операцій над кодами, таких як визначення мінімальної кодової відстані, визначення кодової відстані кодослова до коду, сортування коду, надання користувачу простого та зрозумілого графічного інтерфейсу для зручності роботи з програмою.
Комплекс програм реалізований мовою програмування Java, яка підтримується усіма популярними операційними системами, з використанням стандартної бібліотеки JavaFX, для розробки графічних інтерфейсів.The bachelors project includes an explanatory note (97 pages, 41 drawings, 7 annexes). In this work, the topics of error correction and error detection coding, finding maximal clique of graph have been researched. Different types of coding were considered, the problem of analytic speed of code was described and Bron-Kerbosh algorithm was analyzed. Based on specifics of equivalents codes and Hamming graph the methods of algorithm optimization for finding maximal undivided error correcting code were suggested. It has been decided to develop a complex of program which will help to calculate and research error correcting codes. The concrete requirements and functionality for the complex were formulated: possibility to search maximal undivided error correcting code according to parameters provided by user, stop work of complex in the moment with saving intermediate data algorithm are working with, loading the saved data and continue work after algorithm had been stopped, the possibility to perform some operations with codes like compute the minimal code distance, compute minimal code distance between a word and a code, sort code, provide simple and understandable graphical user interface for comfortable working with program. The complex of programs is implemented by Java programming language which is supported by all the most popular operation systems using native library JavaFX for developing graphical user interface.
2
Mumba, Nephtale Bvalamanja. "Codes, graphs and designs from maximal subgroups of alternating groups." University of the Western Cape, 2018. http://hdl.handle.net/11394/6165.
Повний текст джерелаАнотація:
Philosophiae Doctor - PhD (Mathematics)The main theme of this thesis is the construction of linear codes from adjacency matrices or sub-matrices of adjacency matrices of regular graphs. We first examine the binary codes from the row span of biadjacency matrices and their transposes for some classes of bipartite graphs. In this case we consider a sub-matrix of an adjacency matrix of a graph as the generator of the code. We then shift our attention to uniform subset graphs by exploring the automorphism groups of graph covers and some classes of uniform subset graphs. In the sequel, we explore equal codes from adjacency matrices of non-isomorphic uniform subset graphs and finally consider codes generated by an adjacency matrix formed by adding adjacency matrices of two classes of uniform subset graphs.
3
Guesnet, Yannick. "Codes et interprétations." Rouen, 2001. http://www.theses.fr/2001ROUES019.
Повний текст джерелаАнотація:
Les travaux présentés dans ce mémoire se situent dans le cadre de la théorie des codes à longueurs variables. Nous introduisons deux nouvelles classes de codes : celle des codes à délai d'interprétation fini et celle des codes adjacents. Nous montrons que ces codes satisfont une extension au théorème du défaut. Nous montrons également l'équivalence entre la notion de maximalité dans la classe des codes à délai d'interprétation fini et celle de maximalité dans la classe des codes en général pour les codes à délai d'interprétation fini coupants. Nous proposons en outre deux méthodes de complétions : l'une permet de compléter tout code à délai d'interprétation fini coupant en un code à délai d'interprétation fini maximal et l'autre permet de compléter tout code synchronisant en un code maximal et synchronisant. Ces deux méthodes préservent la rationalité des ensembles. Nous nous intéressons dans un dernier temps aux codes denses : nous montrons qu'il n'y a pas équivalence entre la maximalité dans la classe des codes circulaires et la maximalité dans la classe des codes dans le cas des codes circulaires denses. Enfin, nous donnons une méthode permettant de compléter tout code bifixe coupant et non maximal en un code dense, bifixe, maximal dans la classe des codes bifixes et non maximal dans la classe des codes.
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Dhanasetty, Abhishek. "Enumerating Approximate Maximal Cliques in a Distributed Framework." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1617104719399743.
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Bärmann, Daniel. "Aufzählen von DNA-Codes." Master's thesis, Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2006/1026/.
Повний текст джерелаАнотація:
In dieser Arbeit wird ein Modell zum Aufzählen von DNA-Codes entwickelt.
Indem eine Ordnung auf der Menge aller DNA-Codewörter eingeführt und auf die Menge aller Codes erweitert wird, erlaubt das Modell das Auffinden von DNA-Codes mit bestimmten Eigenschaften, wie Überlappungsfreiheit, Konformität, Kommafreiheit, Stickyfreiheit, Überhangfreiheit, Teilwortkonformität und anderer bezüglich einer gegebenen Involution auf der Menge der Codewörter. Ein auf Grundlage des geschaffenen Modells entstandenes Werkzeug erlaubt das Suchen von Codes mit beliebigen Kombinationen von Codeeigenschaften.
Ein weiterer wesentlicher Bestandteil dieser Arbeit ist die Untersuchung der Optimalität von DNA-Codes bezüglich ihrer Informationsrate sowie das Finden solider DNA-Codes.In this work a model for enumerating DNA codes is developed. By applying an order on the set of DNA codewords and extending this order on the set of codes, this model assists in the discovery of DNA codes with properties like non-overlappingness, compliance, comma-freeness, sticky-freeness, overhang-freeness, subword-compliance, solidness and others with respect to a given involution on the set of codewords. This tool can be used to find codes with arbitrary combinations of code properties with respect to the standard Watson-Crick-DNA involution. The work also investigates DNA codes with respect to the optimizing of the information rate, as well as finding solid DNA codes.
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Santos, Josenildo Brandão. "Construção de STBCs de Ordem Maximal em Álgebras Centrais Simples." Universidade Federal da Paraíba, 2012. http://tede.biblioteca.ufpb.br:8080/handle/tede/7404.
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Previous issue date: 2012-09-28Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this dissertation, a way to build dense STBCs with full diversity of maximal order in central simple algebra will be presented. We constructed a retriculated ST code with a nonzero determinant for a quad antenna MISO transmission. Also, we will present a general algorithm to test the limit of a given order, since by the use of a maximum order instead of just the algebraic integer ring, we can increase the capacity of the code without a loss in the minimum determinant. Furthermore, by using the ideal of a maximum order we can further improve the code, as we increase the minimum determinant.
Nesta dissertação, será apresentada uma maneira para construir STBCs denso com diversidade completa, de ordem maximal em álgebras centrais simples. Construiremos um código reticulado ST com determinante não nulo para uma aplicação de quatro an- tenas de transmissão MISO. Apresentaremos também, um algoritmo geral para testar a maximalidade de uma ordem dada, uma vez que com o uso de uma ordem maximal em vez de apenas o anel dos inteiros algébricos, conseguimos um aumento na capacidade do código sem perda no determinante mínimo. Além disso, utilizando o ideal de uma ordem maximal melhoramos ainda mais o código, à medida que aumentamos o determinante mínimo.
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Chi, Zhanjiang. "Performance Analysis of Maximal-Ratio Combining and Space-Time Block Codes with Transmit Antenna Selection over Nakagami-m Fading Channels." School of Electrical and Information Engineering, 2007. http://hdl.handle.net/2123/2012.
Повний текст джерелаАнотація:
Master of Engineering (Research)The latest wireless communication techniques such as highspeed wireless internet application demand higher data rates and better quality of service (QoS). However, transmission reliability is still degraded by harsh propagation channels. Multiple-input multiple-output (MIMO) systems can increase the system capacity and improve transmission reliability. By transmitting multiple copies of data, a MIMO system can effectively combat the effects of fading. Due to the high hardware cost of a MIMO system, antenna selection techniques have been applied in MIMO system design to reduce the system complexity and cost. The Nakagami-m distribution has been considered for MIMO channel modeling since a wide range of fading channels, from severe to moderate, can be modeled by using Nakagami-m distribution. The Rayleigh distribution is a special case of the Nakagami-m distribution. In this thesis, we analyze the error performance of two MIMO schemes: maximal-ratio combining with transmit antenna selection (the TAS/MRC scheme) and space-time block codes with transmit antenna selection (the TAS/STBC scheme) over Nakagami-m fading channels. In the TAS/MRC scheme, one of multiple transmit antennas, which maximizes the total received signal-to-noise ratio (SNR), is selected for uncoded data transmission. First we use a moment generating function based (MGF-based) approach to derive the bit error rate (BER) expressions for binary phase shift keying (BPSK), the symbol error rate (SER) expressions for M-ray phase shift keying (MPSK) and M-ray quadrature amplitude modulation (MQAM) of the TAS/MRC scheme over Nakagami-m fading channels with arbitrary and integer fading parameters m. The asymptotic performance is also investigated. It is revealed that the asymptotic diversity order is equal to the product of the Nakagami fading parameter m, the number of transmit antenna Lt and the number of receive antenna Lr as if all transmit antenna were used. Then a Gaussian Q-functions approach is used to investigate the error performance of the TAS/STBC scheme over Nakagami-m fading channels. In the TAS/STBC scheme, two transmit antennas, which maximize the output SNR, are selected for transmission. The exact and asymptotic BER expressions for BPSK are obtained for the TAS/STBC schemes with three and four transmit antennas. It is shown that the TAS/STBC scheme can provide a full diversity order of mLtLr.
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Panagos, Adam G., and Kurt Kosbar. "A METHOD FOR FINDING BETTER SPACE-TIME CODES FOR MIMO CHANNELS." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604782.
Повний текст джерелаАнотація:
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaMultiple-input multiple output (MIMO) communication systems can have dramatically higher throughput than single-input, single-output systems. Unfortunately, it can be difficult to find the space-time codes these systems need to achieve their potential. Previously published results located good codes by minimizing the maximum correlation between transmitted signals. This paper shows how this min-max method may produce sub-optimal codes. A new method which sorts codes based on the union bound of pairwise error probabilities is presented. This new technique can identify superior MIMO codes, providing higher system throughput without increasing the transmitted power or bandwidth requirements.
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Xingyu, Luo, and Zhang Qishan. "A PARALLEL -SEQUENTIAL SEARCH ALGORITHM IN A HIGH DYNAMIC GPS RECEIVER." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/607533.
Повний текст джерелаАнотація:
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, CaliforniaIt is need to design acquisition and tracking for code loop and carrier loop to detect the high dynamic Global Position System (GPS) signal. Acquiring signal quickly and shortening acquisition time in the cold case are key technology of a high dynamic GPS receiver. Moreover, fast acquisition of C/A code is the base of code tracking and carrier acquisition and tracking. This paper describes elements and implementation of a new parallel-sequential search Algorithm to acquire C/A code of the high dynamic GPS signal. And combined with a 12-channel correlator named GP2021 produced by GEC Co., the arithmetic implementation to acquire C/A code of the high dynamic GPS signal used sequential search based on DSP technology is also given.
10
Chan, Evelyn Yu-San. "Heuristic optimisation for the minimum distance problem." Thesis, Nottingham Trent University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324569.
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Chi, Xuan. "The Impact of Channel Estimation Error on Space-Time Block and Trellis Codes in Flat and Frequency Selective Channels." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/33963.
Повний текст джерелаАнотація:
Recently multiple antenna systems have received significant attention from researchers as a means to improve the energy and spectral efficiency of wireless systems. Among many classes of schemes, Space-Time Block codes (STBC) and Space-Time Trellis codes (STTC) have been the subject of many investigations.Both techniques provide a means for combatting the effects of multipath fading without adding much complexity to the receiver. This is especially useful in the downlink of wireless systems. In this thesis we investigate the impact of channel estimation error on the performance of both STBC and STTC.
Channel estimation is especially important to consider in multiple antenna systems since (A) for coherent systems there are more channels to estimate due to multiple antennas and (B) the decoupling of data streams relies on correct channel estimation. The latter effect is due to the intentional cross-talk introduced into STBC.
Master of Science
12
Broms, Carl Erik. "Concrete flat slabs and footings : Design method for punching and detailing for ductility." Doctoral thesis, KTH, Brobyggnad inkl stålbyggnad, 2005. http://innopac.lib.kth.se/search/.
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Thesis (Ph.D.)--Royal Institute of Technology (Stockholm, Sweden), 2005."ISRN KTH/BKN/B-80-SE." "Dept. of Civil and Architectural Engineering, Division of Structural Design and Bridges, Royal Institute of Technology, Stockholm. " Includes bibliographical references. Available from the Royal Institute of Technology (Sweden) Library as a .pdf document http://www.lib.kth.se/main/eng/
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Rahim, Fatih. "A Variable Neighborhood Search Procedure For The Combined Location With Partial Coverage And Selective Traveling Salesman Problem." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611949/index.pdf.
Повний текст джерелаАнотація:
In this study, a metaheuristic procedure, particularly a variable neighborhood search procedure, is proposed to solve the combined location and selective traveling salesman problem in glass recycling. The collection of used glass is done by a collecting vehicle that visits a number of predefined collection centers, like restaurants and hospitals that are going to be referred to as compulsory points. Meanwhile, it is desired to locate a predetermined number of bottle banks to
residential areas. The aim is to determine the location of these bottle banks and the route of the collecting vehicle so that all compulsory points and all bottle banks are visited and the maximum profit is obtained. Population zones are defined in residential areas and it is assumed that the people in a particular population zone will recycle their used glass to the closest bottle bank that fully or partially covers their zone. A Variable Neighborhood Search algorithm and its variant have been utilized for the solution of the problem. Computational
experiments have been made on small and medium scale test problems, randomly generated and adapted from the literature.
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Khalil, Maya. "Classes de Steinitz, codes cycliques de Hamming et classes galoisiennes réalisables d'extensions non abéliennes de degré p³." Thesis, Valenciennes, 2016. http://www.theses.fr/2016VALE0012/document.
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Leathers, Jane M. "CRACKING THE LINZ CIRCLE'S SECRET CODES: A SINGER'S GUIDE TO ALTERNATE INTERPRETATIONS OF SCHUBERT LIEDER." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1151698767.
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Williams, Carolyn. "Drawing from voice an exploration of sound in search of representational codes of the unseen : an exegesis submitted to Auckland University of Technology, Master of Arts (Art & Design), 2007 /." AUT University, 2007. http://hdl.handle.net/10292/136.
Повний текст джерелаАнотація:
This project explores the unseen (that which is not considered) in relation to the idea of the existence of another dimension of language. It considers the possibility that, in regard to language, some essential component may have been omitted or unperceived. Through works of art this project explores possibilities for the visual signification of this information. My interest is in exploring ways in which these qualities can be recovered by creating representational codes of the unseen, which evoke a potential for an inclusive language. My enquiry focuses on sound with particular emphasis on 'voice' as a way in which to explore these concepts through visual means. Voice is considered as something which projects or articulates or otherwise could be described as 'speaking'. For example voice is considered in relation to thought, and also the human experience of sound in space. This includes sound generated by self, intrinsic and extrinsic to the body. Voice plays two roles - one as a space from which to retrieve the unseen, and the other as a drawing tool - a way in which to represent what seems unrepresentable.
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Nguyen, Duc Manh. "La programmation DC et la méthode Cross-Entropy pour certaines classes de problèmes en finance, affectation et recherche d’informations : codes et simulations numériques." Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0001/document.
Повний текст джерелаАнотація:
La présente thèse a pour objectif principal de développer des approches déterministes et heuristiques pour résoudre certaines classes de problèmes d'optimisation en Finance, Affectation et Recherche d’Informations. Il s’agit des problèmes d’optimisation non convexe de grande dimension. Nos approches sont basées sur la programmation DC&DCA et la méthode Cross-Entropy (CE). Grâce aux techniques de formulation/reformulation, nous avons donné la formulation DC des problèmes considérés afin d’obtenir leurs solutions en utilisant DCA. En outre, selon la structure des ensembles réalisables de problèmes considérés, nous avons conçu des familles appropriées de distributions pour que la méthode Cross-Entropy puisse être appliquée efficacement. Toutes ces méthodes proposées ont été mises en œuvre avec MATLAB, C/C++ pour confirmer les aspects pratiques et enrichir notre activité de rechercheIn this thesis we focus on developing deterministic and heuristic approaches for solving some classes of optimization problems in Finance, Assignment and Search Information. They are large-scale nonconvex optimization problems. Our approaches are based on DC programming & DCA and the Cross-Entropy method. Due to the techniques of formulation/reformulation, we have given the DC formulation of considered problems such that we can use DCA to obtain their solutions. Also, depending on the structure of feasible sets of considered problems, we have designed appropriate families of distributions such that the Cross-Entropy method could be applied efficiently. All these proposed methods have been implemented with MATLAB, C/C++ to confirm the practical aspects and enrich our research works
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Saglam, Halil Derya. "Simulation performance of multiple-input multiple-output systems employing single-carrier modulation and orthogonal frequency division multiplexing." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FSaglam.pdf.
Повний текст джерелаАнотація:
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, Dec. 2004.Thesis advisor(s): Murali Tummala, Roberto Cristi. Includes bibliographical references (p. 69-71). Also available online.
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Zou, Mengchuan. "Aspects of efficiency in selected problems of computation on large graphs." Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7132.
Повний текст джерелаАнотація:
Cette thèse présente trois travaux liés à la conception d’algorithmes efficaces applicables à des graphes de grande taille. Dans le premier travail, nous nous plaçons dans le cadre du calcul centralisé, et ainsi la question de la généralisation des décompositions modulaires et de la conception d’un algorithme efficace pour ce problème. La décomposition modulaire et la détection de module, sont des moyens de révéler et d’analyser les propriétés modulaires de données structurées. Comme la décomposition modulaire classique est bien étudiée et possède un algorithme de temps linéaire optimal, nous étudions d’abord les généralisations de ces concepts en hypergraphes. C’est un sujet peu étudié mais qui permet de trouver de nouvelles structurations dans les familles de parties. Nous présentons ici des résultats positifs obtenus pour trois définitions de la décomposition modulaire dans les hypergraphes de la littérature. Nous considérons également la généralisation en permettant des erreurs dans les modules de graphes classiques et présentons des résultats négatifs pour deux telles définitions. Le deuxième travail est sur des requêtes de données dans un graphe. Ici, le modèle diffère des scénarios classiques dans le sens que nous ne concevons pas d’algorithmes pour résoudre un problème original, mais nous supposons qu’il existe un oracle fournissant des informations partielles sur la solution de problème initial, où les oracle ont une consommation de temps ou de ressources de requête que nous modélisons en tant que coûts, et nous avons besoin d’un algorithme décidant comment interroger efficacement l’oracle pour obtenir la solution exacte au problème initial. L’efficacité ici concerne le coût de la requête. Nous étudions un problème de la méthode de dichotomie généralisée pour lequel nous calculons une stratégie d’interrogation efficace afin de trouver une cible cachée dans le graphe. Nous présentons les résultats de nos travaux sur l’approximation de la stratégie optimale de recherche en dichotomie généralisée sur les arbres pondérés. Notre troisième travail est sur la question de l’efficacité de la mémoire. La configuration dans laquelle nous étudions sont des calculs distribués et avec la limitation en mémoire. Plus précisément, chaque nœud stocke ses données locales en échangeant des données par transmission de messages et est en mesure de procéder à des calculs locaux. Ceci est similaire au modèle LOCAL / CONGEST en calcul distribué, mais notre modèle requiert en outre que chaque nœud ne puisse stocker qu’un nombre constant de variables w.r.t. son degré. Ce modèle peut également décrire des algorithmes naturels. Nous implémentons une procédure existante de repondération multiplicative pour approximer le problème de flux maximal sur ce modèle. D’un point de vue méthodologique, les trois types d’efficacité que nous avons étudiées correspondent aux trois types de scénarios suivants: – Le premier est le plus classique. Considérant un problème, nous essayons de concevoir à la main l’algorithme le plus efficace. – Dans le second, l’efficacité est considérée comme un objectif. Nous modélisons les coûts de requête comme une fonction objectif, et utilisons des techniques d’algorithme d’approximation pour obtenir la conception d’une stratégie efficace. – Dans le troisième, l’efficacité est en fait posée comme une contrainte de mémoire et nous concevons un algorithme sous cette contrainteThis thesis presents three works on different aspects of efficiency of algorithm design for large scale graph computations. In the first work, we consider a setting of classical centralized computing, and we consider the question of generalizing modular decompositions and designing time efficient algorithm for this problem. Modular decomposition, and more broadly module detection, are ways to reveal and analyze modular properties in structured data. As the classical modular decomposition is well studied and have an optimal linear time algorithm, we firstly study the generalizations of these concepts to hypergraphs and present here positive results obtained for three definitions of modular decomposition in hypergraphs from the literature. We also consider the generalization of allowing errors in classical graph modules and present negative results for two this kind of definitions. The second work focuses on graph data query scenarios. Here the model differs from classical computing scenarios in that we are not designing algorithms to solve an original problem, but we assume that there is an oracle which provides partial information about the solution to the original problem, where oracle queries have time or resource consumption, which we model as costs, and we need to have an algorithm deciding how to efficiently query the oracle to get the exact solution to the original problem, thus here the efficiency is addressing to the query costs. We study the generalized binary search problem for which we compute an efficient query strategy to find a hidden target in graphs. We present the results of our work on approximating the optimal strategy of generalized binary search on weighted trees. Our third work draws attention to the question of memory efficiency. The setup in which we perform our computations is distributed and memory restricted. Specifically, every node stores its local data, exchanging data by message passing, and is able to proceed local computations. This is similar to the LOCAL/CONGEST model in distributed computing, but our model additionally requires that every node can only store a constant number of variables w.r.t. its degree. This model can also describe natural algorithms. We implement an existing procedure of multiplicative reweighting for approximating the maximum s–t flow problem on this model, this type of methodology may potentially provide new opportunities for the field of local or natural algorithms. From a methodological point of view, the three types of efficiency concerns correspond to the following types of scenarios: the first one is the most classical one given the problem, we try to design by hand the more efficient algorithm; the second one, the efficiency is regarded as an objective function .where we model query costs as an objective function, and using approximation algorithm techniques to get a good design of efficient strategy; the third one, the efficiency is in fact posed as a constraint of memory and we design algorithm under this constraint
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Shieh, Shin-Lin, and 謝欣霖. "Near Maximum-Likelihood Sequential-Search Decoding Algorithms for Binary Convolutional Codes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/29374672756621349262.
Повний текст джерелаАнотація:
博士國立交通大學
電信工程系所
96
In this work, the maximum-likelihood sequential-search decoding algorithm proposed in [17] is revisited. By replacing the conventional Fano metric with one that is derived based on the Wagner rule, the sequential-search decoding in [17] guarantees the maximum-likelihood (ML) performance, and was therefore named the maximum-likelihood sequential decoding algorithm (MLSDA). It was then concluded by simulations that when the MLSDA is operated over the convolutional code trellis, its software computational complexity is in general considerably smaller than that of the Viterbi algorithm. A common problem on sequential-type decoding is that at the signal-to-noise ratio (SNR) below the one corresponding to the cut off rate, the average decoding complexity and the required stack size grow rapidly with the information length [25]. This problem, to some extent, prevents the practical use of sequential-type decoding from codes with long information sequence. In order to alleviate the problem in the MLSDA, we propose to directly eliminate the top path whose end node is ∆-trellis-level prior to the farthest one among all nodes that have been expanded thus far by the sequential search, which we termed the early elimination. We then analyze the early-elimination window that results in negligible performance degradation for the MLSDA. Our asymptotic-based analytical result indicates that the required early elimination window for negligible performance degradation is around three times (resp. 2.2-fold) of the constraint length for rate one-half convolutional codes under additive white Gaussian (resp. binary symmetric) channel. For rate one-third convolutional codes, the required early-elimination window reduces to two times (resp. 1.2-fold) of the constraint length for the same channel. The theoretical level thresholds almost coincide with the simulation results. As a consequence of small early elimination window required for near maximum-likelihood performance, the MLSDA with early elimination modification rules out considerable computational burdens, as well as memory requirement, by directly eliminating a big number of the top paths. This makes the MLSDA with early elimination suitable for applications that dictate a low-complexity software implementation with near maximum-likelihood performance. The upper bounds of decoding complexity of both the MLSDAs with and without early elimination are subsequently derived by utilizing the Berry-Esseen inequality. Both the upper bound and the simulated complexity indicate that the average decoding complexity per output bit for the MLSDA with early elimination is almost irrelevant to the memory order, as well as the message length, for medium to high SNRs.
21
Deugau, Christopher Jordan. "Algorithms and combinatorics of maximal compact codes." Thesis, 2006. http://hdl.handle.net/1828/2101.
Повний текст джерелаАнотація:
The implementation of two different algorithms for generating compact codes of some size N are presented. An analysis of both algorithms is given. in an attempt to prove whether or not the algorithms run in constant amortized time. Meta-Fibonacci sequences are also investigated in this paper. Using a particular numbering on k-ary trees, we find that a group of meta-Fibonacci sequences count the number of nodes at the bottom level of these k-ary trees. These meta-Fibonacci sequences are also related to compact codes. Finally, generating functions are proved for the meta-Fibonacci sequences discussed.
22
von, Keitz Michael. "A Search for Maximal Diversity Amongst Paired Prisoner's Dilemma Strategies." Thesis, 2011. http://hdl.handle.net/10214/3210.
Повний текст джерелаАнотація:
Previous research has identified linear boundaries within a normalized unit square for specific paired strategies within the iterated prisoner's dilemma schema. In this work, general methods of capturing linear boundaries are developed and demonstrated on a wider variety of paired strategies. The method is also tested using an alternate scoring method. An application of Burnside's Lemma simplifies the number of neighbourhood configurations to be considered. In addition, Shannon entropy is used as a means of evaluating diversity of agents evolved with different payoff matrices, by which one might locate a game that is as balanced as possible.
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YELLOW, SHEA-YU, and 黃協瑜. "Predictive Search Approach to Maximal Frequent Itemset Mining on P2P Networks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/82549427844399954467.
Повний текст джерела
24
Tsai, shian-ming, and 蔡憲銘. "Search for Perfect Complementary Codes Using Nonlinear Numerical Methods." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/55436405525386719382.
Повний текст джерелаАнотація:
碩士國立中山大學
通訊工程研究所
93
This paper present three kinds of nonlinear numerical methods to search for perfect complementary codes, include Newtonian Methods、Levenberg-Marquardt Algorithm and Trust-Regions. By searching for the solution of theses nonlinear equations, we can get complementary codes when setting for the length of element codes and the flock size. These search results is very generous. Complete complementary codes、super complementary code and poly-phase complementary code are subsets of these searching results。 These nonlinear equations are set to have ideal auto-correlation and cross-correlation properties, so the searching results of these nonlinear equations are still have perfect orthogonal complementary properties. Because the orthogonal complementary code is obtained via these nonlinear equations, the results are the most generous. So nonlinear numerical method is a good choice to search for another complementary code we don’t know.
25
Chen, Wei-Ting, and 陳威廷. "Computer Search of Super-Orthogonal Space-Time Trellis Codes." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/68u65j.
Повний текст джерелаАнотація:
碩士國立中央大學
通訊工程研究所
97
Super-orthogonal space-time trellis codes (SOSTTCs) designed by hand can improve the performance of space-time trellis codes. In 2007, a representation of SOSTTCs based on a generator matrix was proposed which allows systematic searches of possible codes. In this scheme, the rotation of the constellation is determined before computer searches. However, the optimality of the rotation cannot be guaranteed. In this thesis, we propose three different representations of SOSTTCs which are also based on a generator matrix. In the proposed schemes, the rotation of the constellation is determined by computer searches. New codes of our schemes that outperform previously known codes are found.
26
Wang, Yen-Hwang, and 王炎煌. "STUDIES ON SEARCH ALGORITHM FOR LOW COMPLEXITY CONVOLUTIONAL CODES." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/12145906014575789051.
Повний текст джерелаАнотація:
碩士大同大學
通訊工程研究所
94
In this thesis, we proposed a modified search algorithm to search convolutional codes which possesses high error-correcting capability and low computational complexity. Using this new search algorithm, searching computation decreases exponentially .The rate of computation of the modified algorithm and conventional one extremely low especially at high code rate convolutional codes. According to our formula, the computation of modified search algorithm over that of conventional search algorithm at code rate 4/5 reaches 0.5%. New codes of code rate 2/3, 2/4, 3/4 and 4/5 are also found in this paper. Under the merit of the modified algorithm, new good codes with very high code rate and low complexity can be discovered rapidly and put into practice in the future.
27
Chen, Hao-Chao, and 陳蒿照. "Computer Search for Good (n, n-1) Convolutional Codes." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/92715023550086240026.
Повний текст джерелаАнотація:
碩士國立臺灣大學
電信工程學研究所
91
In the paper “On (n, n-1) convolutional codes with low trellis complexity” written by Hung-Hua Tang and Mao-Chao Lin, some good (n, n-1) convolutional codes are found through a new algorithm. However, the search was not complete for all the possible values of (a measure of decoding complexity for an (n, n-1) code). In this thesis, a more complete search is done. For the convolutional codes already found in the aforementioned paper, we also consider the effect of row operations on the generator matrices to achieve better information weight spectra. Comparisons with some best-known punctured convolutional codes are given in this thesis.
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Huang, De Zheng, and 黃德正. "Some extended results on the search for good convolutional codes." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/39779036073390346152.
Повний текст джерела
29
Liou, Reay Ching, and 劉瑞清. "Studying for Fast Chien Search Decoding of Reed-Solomon Codes." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/21864649022407082375.
Повний текст джерелаАнотація:
碩士中原大學
電機工程研究所
82
In recently, Y. R. Shayan developed a fast decoding algorithm for binary double error - correcting BCH codes. The decoder can work on the high data rate transmission system. The decoding method is modified by the paper for using on the fast decoder of Reed-Solomon codes. A binary-decision approach to the Chien search is introduced to reduce the search time by a factor of two , and hence to increase the decoding speed. The new decoding algorithm is called the modified fast Chien search. The modified fast Chien Search algorithm can be applied on the decoder of Reed - Solomon codes. The new method use the fast decoding advantages of the microprocessor. Because the codewords are not all saved in the the memory ( ROM ), the memory is not required very large. It solves the problems of memory when the code's length is very long. A (15,11) Reed - Solomon decoder is used as design example to illustrate the operating procedure of the new decoding algorithm. The modified fast Chien Search algorithm not only can be applied on the decoder of Reed - Solomon codes. It also can be applied on the decoder of binary BCH codes. In microprocessor -based designs, owing to recent advances in solid - stste technology , enough capability can be placed on a single die , thereby reducing the part count. As an example, a decoder can be designed using the microprocessor for a single - chip solution. The only limitation to the applicability of microprocessors to Reed- Solomon Codes is their processing time. However, because of rapid advances in solid-state technology the speed limitation will be overcome in the near future. As a solution to this problem VLSI implementations of the decoders can be used.
30
Liu, Rui-Qing, and 劉瑞清. "Studying for fast chien search decoding of reed-solomon codes." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/57266129034287847959.
Повний текст джерела
31
Min, Ying-Ju, and 閔瀅如. "Cell Search for Cell-Based OFDM Systems Using Quasi Complete Complementary Codes." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/46277927979017757334.
Повний текст джерелаАнотація:
碩士國立清華大學
通訊工程研究所
95
Establishing a radio link in cell-based mobile communication systems involves searching and synchronizing the downlink known pattern of sequences associated with the base stations. The searching process, often referred to as cell search, is usually completed by preamble sequences. Therefore, the performance of cell search depends greatly on the preamble se- quences. In this thesis, we propose a construction of quasi complete complementary codes (QCCCs) from Reed-Muller (RM) codes. Since the constructed QCCCs have good auto- correlation and cross-correlation properties, we employ them as preamble sequences and propose a preamble structure based on QCCCs. Furthermore, the constructed QCCCs have low peak-to-average power ratio (PAPR), and hence they are suitable for use in orthogonal frequency division multiplexing (OFDM) systems. We compare the cell search performance of using QCCCs as preambles with that of the worldwide interoperability for microwave access (WiMAX, also referred to as IEEE standard 802.16e) preambles. Simulation results show that there is minor or acceptable performance degradation with our QCCCs employed as preambles, while the rich algebraic structures of QCCCs potentially permit low-complexity encoding and decoding.
32
LIN, GI-ZHANG, and 林其璋. "Computer search for binary cyclic unequal error protection codes of odd lengths." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/78459717529243280471.
Повний текст джерела
33
Chang, Chin-hsiang, and 張秦祥. "Use of Parallel Computing Techniques to Search for Perfectly Orthogonal Complementary Codes." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/53819809597736997079.
Повний текст джерелаАнотація:
碩士國立中山大學
通訊工程研究所
93
Because using the perfect orthogonal code in CDMA system means elimination of multi-path interference and multiple access interference, we will discuss this aspect in this thesis. At first, we address a algorithm to how to search a flock of perfect orthogonal code, which consisting of many codes have a characteristic of perfect auto-correlation and perfect cross-correlation to each other. Following, we will compare perfect orthogonal code we find with the present complementary codes include complete complementary code (CCC), super complementary code (SCC), and two-dimensional orthogonal variable spreading code (2D-OVSF code). Considering that the run time of searching perfect orthogonal code is long in case of high processing gain (PG), we construct a PC cluster based Linux O.S or Windows O.S for the operation of parallel program to faster our production of perfect orthogonal code.
34
Lin, Tien-Yu, and 林典育. "Study of Hybrid Automatic Request Schemes and Tree-Search Decoding of Linear Block Codes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71231770591464490295.
Повний текст джерелаАнотація:
博士國立臺灣大學
電信工程學研究所
101
In this dissertation, we study two topics on communications: hybrid automatic repeat request (ARQ) and tree-search decoding of linear block codes. For the first topic, we propose an hybrid ARQ (HARQ) scheme with subpacket transmission and subpacket scheduling for systems with constant packet lengths. In this scheme, each transmission packet comprises two subpackets of equal lengths. As compared to the conventional type II HARQ scheme, the proposed HARQ scheme can more effectively control the error-correcting capability and thus attain better throughput efficiency in the moderate to high signal-to-noise ratios (SNR) regime. Based on the proposed HARQ scheme, we then presents two modified versions of the proposed scheme. The first version with higher complexity, can provide further throughput improvement in low SNR. The second version, with the highest complexity, can obtain additional throughput than the first version in moderate to high SNR. For the second topic, we investigate a tree-search decoding algorithm, named A*, and aim to effectively reduce the decoding latency (complexity). We propose two complexity-reduction techniques for the A* algorithm. The first technique is that the searching is embedded with depth constraints in which the numbers of bit difference from the most reliable positions at different depths are limited. In the second technique, apart from the tree searching, the algorithm employs generation of candidate codewords based on processing the newly updated candidate codeword. For both proposed algorithms, the searching complexity can be significantly reduced at the cost of slight performance loss. In addition, the two proposed techniques can be effectively combined to obtain a more efficient modified A* algorithm. We also investigate the A* decoding for block coded schemes with interblock memory. With interblock memory, both the error performance and average decoding latency of the A* algorithm can be significantly improved in the high SNR regime. Finally, we discuss a HARQ scheme which employs packet division together with the A* decoding. This scheme is easy to be implemented and can perform as well throughput as the conventional type II HARQ scheme.
35
Ho, Tuan Minh. "Analysis and testing of a new hybrid parallel search scheme for spread spectrum codes acquisition." Thesis, 1987. http://spectrum.library.concordia.ca/2502/1/ML37105.pdf.
Повний текст джерела
36
Lu, Kuei-Ying, and 呂奎穎. "Further Research on Quasi Complete Complementary Codes for Cell Search in Cell-Based OFDM Systems." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/31929633315678693728.
Повний текст джерелаАнотація:
碩士國立清華大學
通訊工程研究所
96
Establishing a radio link in cell-based mobile communication systems involves searching and synchronizing the downlink known pattern of sequences associated with the base stations. The searching process, often referred to as cell search, is usually done with preamble sequences. Therefore, the performance of cell search depends greatly on the employed preamble sequences. In this thesis, we propose a construction of quasi complete complementary codes (QCCCs) from Reed-Muller (RM) codes. Since the constructed QCCCs have good auto-correlation and cross-correlation properties, three preamble structures based on QCCCs are proposed in the thesis. Furthermore, the constructed QCCCs have low peak-to-average power ratios (PAPRs) and proposed in this thesis are hence suitable for use in orthogonal frequency division multiplexing (OFDM) systems. Efficient encoding and decoding algorithms are also proposed based on the rich algebraic structures of QCCCs. Compared with the computer-searched pseudo noise (PN) sequence preambles employed in the WiMAX system, great complexity reduction in encoding and detection can be obtain for QCCC-based preambles. Simulation results also show that for cell search the QCCC-based preambles perform as well as PN preambles.
37
Wu, Chien-Tien, and 吳千恬. "Architectures for Syndrome Generation and Error-Location Search in the Decoding of Algebraic-Geometry Codes over a Tower of Hermitian Function Fields." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/13941568952116674334.
Повний текст джерела
38
Saif, Khan Mohammed. "Low-Complexity Detection And Precoding In High Spectral Efficiency Large-MIMO Systems." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1914.
Повний текст джерела
39
Nikjah, Reza. "Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks." Phd thesis, 2010. http://hdl.handle.net/10048/1674.
Повний текст джерелаАнотація:
The importance of cooperative relaying communication in substituting for, or complementing,
multiantenna systems is described, and a brief literature review is presented.
Amplify-and-forward (AF) and decode-and-forward (DF) relaying are investigated and
compared for a dual-hop relay channel. The optimal strategy, source and relay optimal
power allocation, and maximum cooperative gain are determined for the relay channel. It
is shown that while DF relaying is preferable to AF relaying for strong source-relay links,
AF relaying leads to more gain for strong source-destination or relay-destination links.
Superimposed and selection AF relaying are investigated for multirelay, dual-hop relaying.
Selection AF relaying is shown to be globally strictly outage suboptimal. A necessary
condition for the selection AF outage optimality, and an upper bound on the probability of
this optimality are obtained. A near-optimal power allocation scheme is derived for superimposed
AF relaying.
The maximum instantaneous rates, outage probabilities, and average capacities of multirelay,
dual-hop relaying schemes are obtained for superimposed, selection, and orthogonal
DF relaying, each with parallel channel cooperation (PCC) or repetition-based cooperation
(RC). It is observed that the PCC over RC gain can be as much as 4 dB for the outage
probabilities and 8.5 dB for the average capacities. Increasing the number of relays deteriorates
the capacity performance of orthogonal relaying, but improves the performances of
the other schemes.
The application of rateless codes to DF relaying networks is studied by investigating
three single-relay protocols, one of which is new, and three novel, low complexity multirelay
protocols for dual-hop networks. The maximum rate and minimum energy per bit and
per symbol are derived for the single-relay protocols under a peak power and an average
power constraint. The long-term average rate and energy per bit, and relay-to-source usage
ratio (RSUR), a new performance measure, are evaluated for the single-relay and multirelay
protocols. The new single-relay protocol is the most energy efficient single-relay scheme
in most cases. All the multirelay protocols exhibit near-optimal rate performances, but are
vastly different in the RSUR.
Several future research directions for fixed-rate and rateless coded cooperative systems,
and frameworks for comparing these systems, are suggested.Communications