Detalhes bibliográficos
| Ano de defesa: |
2014 |
| Autor(a) principal: |
Aguiar Júnior, Dióscoros Brito |
| Orientador(a): |
Vargas Júnior, Valdivino
 |
| Banca de defesa: |
Vargas Júnior, Valdivino,
Gava, Renato Jacob,
Silva, Tatiane Ferreira do Nascimento Melo da |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
|
| Programa de Pós-Graduação: |
Programa de Pós-graduação em Matemática (IME)
|
| Departamento: |
Instituto de Matemática e Estatística - IME (RG)
|
| País: |
Brasil
|
| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://repositorio.bc.ufg.br/tede/handle/tde/2976
|
Resumo: |
In this work ,we will consider two stochastic models for evolution os species. First, births and deaths of species occur with constant probabilities. Each new species is associated with a fitness sampled from the uniform distribution on [0,1]. Every time there is a death event then the type is killed is the one with smallest fitness. We show that there is a sharp phasetransitionwhentheprobabilityislargerthanthedeathprobability.Thesetofspecies with fitness higher than a certain critical value approach an uniform distribution. On the other hand all the species with fitness less than the crital disappear after a finite (random) time. The second model, we consider a stochastic model for species evolution. A new species is born at rateλ and a species dies at rate µ. A random number, sampled from a given distribution F, is associated with each new species and assumed as its fitness, at the time of birth. Likewise the first model, every time there is a death event, the species that is killed is the one with the smallest fitness. We consider the (random) survival time if a species with a given fitness f. We show that the survival time distribution depends crucially on whetherf<fc ,f=fc orf>fc where fc is a critical fitness that is computed explicit. |
