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Matrizes de reflexão com simetria 𝒰𝑞 [osp(2|2𝑚)(2)]
(Universidade Federal de São Carlos, 2012-03-16) Vieira, Ricardo Soares; Santos, Antonio Lima; https://lattes.cnpq.br/8463237728503334; https://lattes.cnpq.br/8265512739743253
In this thesis we present solutions of the graded boundary YANG-BAXTER equations for vertex models with 𝒰𝑞 [osp(2|2𝑚)(2)] symmethy.
Distribuição COM-Poisson na análise de dados de experimentos de quimioprevenção do câncer em animais
(Universidade Federal de São Carlos, 2012-03-16) Ribeiro, Angélica Maria Tortola; Rodrigues, Josemar; https://lattes.cnpq.br/4359114733394761; https://lattes.cnpq.br/6995280108075310
Experiments involving chemical induction of carcinogens in animals are common in the biological area. Interest in these experiments is, in general, evaluating the chemopreventive effect of a substance in the destruction of damaged cells. In this type of study, two variables of interest are the number of induced tumors and their development times. We explored the use of statistical model proposed by Kokoska (1987) for the analysis of experimental data of chemoprevention of cancer in animals. We flexibility the Kokoska s model, subsequently used by Freedman (1993), whereas for the variable number of tumors induced Conway-Maxwell Poisson (COM-Poisson) distribution. This distribution has demonstrated efficiency due to its great flexibility, when compared to other discrete distributions to accommodate problems related to sub-dispersion and super-dispersion often found in count data. The purpose of this paper is to adapt the theory of long-term destructive model (Rodrigues et al., 2011) for experiments chemoprevention of cancer in animals, in order to evaluate the effectiveness of cancer treatments. Unlike the proposed Rodrigues et al. (2011), we formulate a model for the variable number of detected malignant tumors per animal, assuming that the probability of detection is no longer constant, but dependent on the time step. This is an extremely important approach to cancer chemoprevention experiments, because it makes the analysis more realistic and accurate. We conducted a simulation study, in order to evaluate the efficiency of the proposed model and to verify the asymptotic properties of maximum likelihood estimators. We also analyze a real data set presented in the article by Freedman (1993), to demonstrate the efficiency of the COM-Poisson model compared to results obtained by him with the Poisson and Negative Binomial distributions.
Estados parcialmente emaranhados em comunicação quântica
(Universidade Federal de São Carlos, 2012-03-16) Gomes, Raphael Fortes Infante; Rigolin, Gustavo Garcia; https://lattes.cnpq.br/5670956791297779; https://lattes.cnpq.br/5150160591123690
In this master s thesis we approach the entanglement between quantum states as a resource to be used in the transmission of quantum information, particularly in quantum teleportation. Our focus was directed toward the study of partially entangled quantum states, that is, states in which the entanglement degree is below the maximum value allowed by quantum mechanics, since they are more likely to be found in actual devices than maximally entangled states. We review the properties and concepts that characterize vectors and operators from the viewpoint of linear algebra to formally present the postulates of quantum mechanics. We introduced the notion of qubits and showed how these can be applied to computing tasks via quantum logic gates.We explained in details the main quantum teleportation protocols that originated the methods used in this work, highlighting the advantages and disadvantages of each one. We presented protocols with new arrangements and introduced techniques that have improved some of the known methods, providing for those alternatives relating to construction and architecture in the arrangement of the channels. We proved that the probability associated with a multiple teleportation of a single qubit through channels in series tends to the maximum limit for a special case. We showed that imperfect states can be corrected and that it is possible to transmit a single qubit or a pair of qubits using GHZ states and modification of Bell basis states. We discussed the relationship between the final success probability value and the bases and channels degree of entanglement for each method. We concluded the thesis with a general analysis of all protocols, highlighting the most efficient ones with arguments that include theoretical and practical viewpoints.
Combinação de classificadores para inferência dos rejeitados
(Universidade Federal de São Carlos, 2012-03-16) Rocha, Ricardo Ferreira da; Louzada Neto, Francisco; https://lattes.cnpq.br/0994050156415890; https://lattes.cnpq.br/0676420269735630
In credit scoring problems, the interest is to associate to an element who request some kind of credit, a probability of default. However, traditional models uses samples biased because the data obtained from the tenderers has only clients who won a approval of a request for previous credit. In order to reduce the bias sample of these models, we use strategies to extract information about individuals rejected to be able to infer a response, good or bad payer. This is what we call the reject inference. With the use of these strategies, we also use the bagging technique (bootstrap aggregating), which consist in generate models based in some bootstrap samples of the training data in order to get a new predictor, when these models is combined. In this work we will discuss about some of the combination methods in the literature, especially the method of combination by logistic regression, although little used but with interesting results.We'll also discuss some strategies relating to reject inference. Analyses are given through a simulation study, in data sets generated and real data sets of public domain.