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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Algoritmos exatos para o problema de edição de p-Clusters

Cabral, Lucidio dos Anjos Formiga 21 July 2015 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-02-17T11:41:50Z No. of bitstreams: 1 arquivototal.pdf: 1276201 bytes, checksum: 9dd8fad80c483276a40101ee6a782d5b (MD5) / Made available in DSpace on 2016-02-17T11:41:50Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1276201 bytes, checksum: 9dd8fad80c483276a40101ee6a782d5b (MD5) Previous issue date: 2015-07-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work deals with the p-Cluster Editing Problem (p-CEP), which consists in performing a minimum number of editions (additions or removals of edges) in a graph G in order to transform it in a disjoint union of p cliques (clusters), where G and p are input data. p-CEP is a NP-Hard problem with applications in areas such as computational biology and machine learning. To solve this problem, we propose two new mathematical formulations and improvements in a formulation from the literature, as well as new valid inequalities. The three formulations were studied both theoretically, by comparing their linear relaxations, and practically, by implementing three exact algorithms: two based on Branch-and-Cut (BC) and one based on Branch-and-Price (BP). The proposed algorithms were tested in instances with up to 211 vertices. The results show the performance of the algorithms according to the graph density and the ratio between p and the number of vertices. Overall, the BC algorithms were superior to the BP algorithm. However, the latter obtained the best dual bounds in some instances. / Este trabalho trata do Problema de Edi¸c˜ao de p-Clusters (p-PEC), o qual consiste em realizar um n´umero m´ınimo de edi¸c˜oes (adi¸c˜oes ou remo¸c˜oes de arestas) em um grafo G de modo a transform´a-lo em uma uni˜ao disjunta de p cliques (ou clusters), sendo G e p dados de entrada. O p-PEC ´e um problema NP-Dif´ıcil que possui aplica¸c˜oes em ´areas como biologia computacional e aprendizagem de m´aquina. Para resolvˆe-lo, foram propostas duas novas formula¸c˜oes matem´aticas e melhorias em uma formula¸c˜ao proveniente da literatura, bem como novas desigualdades v´alidas. As trˆes formula¸c˜oes consideradas foram estudadas tanto teoricamente, atrav´es da compara¸c˜ao entre as relaxa¸c˜oes lineares, quanto empiricamente, atrav´es do desenvolvimento de trˆes algoritmos exatos: dois baseados em Branch-and-Cut (BC) e um baseado em Branch-and-Price (BP). Os algoritmos foram testados em instˆancias com at´e 211 v´ertices. Os resultados mostram o impacto da raz˜ao entre p e o n´umero de v´ertices, da densidade do grafo e das desigualdades nos desempenhos dos algoritmos. No geral, os algoritmos BC foram superiores ao algoritmo BP. Por´em, em algumas instˆancias, os melhores limites duais foram obtidos pelo algoritmo BP.

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