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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

An optimization modeling framework to evaluate civilians response under active shooter violence situations

Kerlin, Joseph G 11 May 2022 (has links)
Workplace safety is under serious threat due to the increasing trend of active shooter violence in recent years. Therefore, it becomes essential that the safety of a workplace is rigorously and, most importantly, methodologically assessed against active shooter violence. To serve this purpose, this study proposes a machine learning-optimization framework to assess the safety of a building against possible active shooter violence. First, several state-of-the-art machine learning models are employed to predict an agent’s movement decisions (with directions) under different violence scenarios. The predictions are then utilized in a mixed-integer linear programming model to maximize the agent’s utility under a possible active shooter violence situation. The machine learning models and the proposed optimization model considered several building-specific (e.g., staircase/hiding room capacities, building orientation) and agent-specific (e.g., herding behavior, cognitive delay) attributes to realistically capture the violent situation. The performance of the proposed machine learning-optimization framework is assessed on a two-storied test building. Results indicate that the building configuration (e.g., number and location of the staircases, hiding rooms, exits) as well as agent behaviors, such as herding behavior and cognitive delay, play an important role in the recovery/casualty of civilians under a crisis situation.
2

Aplica??o de t?cnicas de aprendizado de m?quina no reconhecimento de classes estruturais de prote?nas

Bittencourt, Valnaide Gomes 25 November 2005 (has links)
Made available in DSpace on 2014-12-17T14:56:03Z (GMT). No. of bitstreams: 1 ValnaideGB.pdf: 1369975 bytes, checksum: 404710d72240200cbd30a9116933d340 (MD5) Previous issue date: 2005-11-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Nowadays, classifying proteins in structural classes, which concerns the inference of patterns in their 3D conformation, is one of the most important open problems in Molecular Biology. The main reason for this is that the function of a protein is intrinsically related to its spatial conformation. However, such conformations are very difficult to be obtained experimentally in laboratory. Thus, this problem has drawn the attention of many researchers in Bioinformatics. Considering the great difference between the number of protein sequences already known and the number of three-dimensional structures determined experimentally, the demand of automated techniques for structural classification of proteins is very high. In this context, computational tools, especially Machine Learning (ML) techniques, have become essential to deal with this problem. In this work, ML techniques are used in the recognition of protein structural classes: Decision Trees, k-Nearest Neighbor, Naive Bayes, Support Vector Machine and Neural Networks. These methods have been chosen because they represent different paradigms of learning and have been widely used in the Bioinfornmatics literature. Aiming to obtain an improvment in the performance of these techniques (individual classifiers), homogeneous (Bagging and Boosting) and heterogeneous (Voting, Stacking and StackingC) multiclassification systems are used. Moreover, since the protein database used in this work presents the problem of imbalanced classes, artificial techniques for class balance (Undersampling Random, Tomek Links, CNN, NCL and OSS) are used to minimize such a problem. In order to evaluate the ML methods, a cross-validation procedure is applied, where the accuracy of the classifiers is measured using the mean of classification error rate, on independent test sets. These means are compared, two by two, by the hypothesis test aiming to evaluate if there is, statistically, a significant difference between them. With respect to the results obtained with the individual classifiers, Support Vector Machine presented the best accuracy. In terms of the multi-classification systems (homogeneous and heterogeneous), they showed, in general, a superior or similar performance when compared to the one achieved by the individual classifiers used - especially Boosting with Decision Tree and the StackingC with Linear Regression as meta classifier. The Voting method, despite of its simplicity, has shown to be adequate for solving the problem presented in this work. The techniques for class balance, on the other hand, have not produced a significant improvement in the global classification error. Nevertheless, the use of such techniques did improve the classification error for the minority class. In this context, the NCL technique has shown to be more appropriated / Atualmente, a classifica??o estrutural de prote?nas, que diz respeito ? infer?ncia de padr?es em sua conforma??o 3D, ? um dos principais problemas em aberto da Biologia Molecular. Esse problema vem recebendo a aten??o de muitos pesquisadores na ?rea de Bioinform?tica pelo fato de as fun??es das prote?nas estarem intrinsecamente relacionadas ?s suas diferentes conforma??es espaciais, que s?o de dif?cil obten??o experimental em laborat?rio. Considerando a grande diferen?a entre o n?mero de seq??ncias de prote?nas conhecidas e o n?mero de estruturas tridimensionais determinadas experimentalmente, ? alta a demanda por t?cnicas automatizadas de classifica??o estrutural de prote?nas. Nesse contexto, as ferramentas computacionais, principalmente as t?cnicas de Aprendizado de M?quina (AM), tornaram-se alternativas essenciais para tratar esse problema. Neste trabalho, t?cnicas de AM s?o empregadas no reconhecimento de classes estruturais de prote?nas: ?rvore de Decis?o, k-Vizinhos Mais Pr?ximos, Na?ve Bayes, M?quinas de Vetores Suporte e Redes Neurais Artificiais. Esses m?todos foram escolhidos por representarem diferentes paradigmas de aprendizado e serem bastante citados na literatura. Visando conseguir uma melhoria de desempenho na solu??o do problema abordado, sistemas de multiclassifica??o homog?nea (Bagging e Boosting) e heterog?nea (Voting, Stacking e StackingC) s?o aplicados nesta pesquisa, usando como base as t?cnicas de AM anteriormente mencionadas. Al?m disso, pelo fato de a base de dados de prote?nas considerada neste trabalho apresentar o problema de classes desbalanceadas, t?cnicas artificiais de balanceamento de classes (Under-sampling Aleat?rio, Tomek Links, CNN, NCL e OSS) s?o utilizadas a fim de minimizar esse problema e melhorar o desempenho dos classificadores. Para a avalia??o dos m?todos de AM, um procedimento de valida??o cruzada ? empregado, em que a acur?cia dos classificadores ? medida atrav?s das m?dias da taxa de classifica??o incorreta nos conjuntos de testes independentes. Essas m?dias s?o comparadas duas a duas pelo teste de hip?tese a fim de avaliar se h? diferen?a estatisticamente significativa entre elas. Com os resultados obtidos, pode-se observar, entre os classificadores base, o desempenho superior do m?todo M?quinas de Vetores Suporte. Os sistemas de multiclassifica??o (homog?nea e heterog?nea), por sua vez, apresentaram, em geral, uma acur?cia superior ou similar a dos classificadores usados como base, destacando-se o Boosting que usou ?rvore de Decis?o em sua forma??o e o StackingC tendo como meta classificador a Regress?o Linear. O m?todo Voting, apesar de sua simplicidade, tamb?m mostrou-se adequado para a solu??o do problema considerado nesta disserta??o. Em rela??o ?s t?cnicas de balanceamento de classes, n?o foram alcan?ados melhores resultados de classifica??o global com as bases de dados obtidas com a aplica??o de tais t?cnicas. No entanto, foi poss?vel uma melhor classifica??o espec?fica da classe minorit?ria, de dif?cil aprendizado. A t?cnica NCL foi a que se mostrou mais apropriada ao balanceamento de classes da base de dados de prote?nas
3

Contributions à l'étude et à la reconnaissance automatique de la parole en Fongbe / Contributions to the study of automatic speech recognitionon Fongbe

Laleye, Frejus Adissa Akintola 10 December 2016 (has links)
L'une des difficultés d'une langue peu dotée est l'inexistence des services liés aux technologies du traitement de l'écrit et de l'oral. Dans cette thèse, nous avons affronté la problématique de l'étude acoustique de la parole isolée et de la parole continue en Fongbe dans le cadre de la reconnaissance automatique de la parole. La complexité tonale de l'oral et la récente convention de l'écriture du Fongbe nous ont conduit à étudier le Fongbe sur toute la chaîne de la reconnaissance automatique de la parole. En plus des ressources linguistiques collectées (vocabulaires, grands corpus de texte, grands corpus de parole, dictionnaires de prononciation) pour permettre la construction des algorithmes, nous avons proposé une recette complète d'algorithmes (incluant des algorithmes de classification et de reconnaissance de phonèmes isolés et de segmentation de la parole continue en syllabe), basés sur une étude acoustique des différents sons, pour le traitement automatique du Fongbe. Dans ce manuscrit, nous avons aussi présenté une méthodologie de développement de modèles accoustiques et de modèles du langage pour faciliter la reconnaissance automatique de la parole en Fongbe. Dans cette étude, il a été proposé et évalué une modélisation acoustique à base de graphèmes (vu que le Fongbe ne dispose pas encore de dictionnaire phonétique) et aussi l'impact de la prononciation tonale sur la performance d'un système RAP en Fongbe. Enfin, les ressources écrites et orales collectées pour le Fongbe ainsi que les résultats expérimentaux obtenus pour chaque aspect de la chaîne de RAP en Fongbe valident le potentiel des méthodes et algorithmes que nous avons proposés. / One of the difficulties of an unresourced language is the lack of technology services in the speech and text processing. In this thesis, we faced the problematic of an acoustical study of the isolated and continous speech in Fongbe as part of the speech recognition. Tonal complexity of the oral and the recent agreement of writing the Fongbe led us to study the Fongbe throughout the chain of an automatic speech recognition. In addition to the collected linguistic resources (vocabularies, large text and speech corpus, pronunciation dictionaries) for building the algorithms, we proposed a complete recipe of algorithms (including algorithms of classification and recognition of isolated phonemes and segmentation of continuous speech into syllable), based on an acoustic study of the different sounds, for Fongbe automatic processing. In this manuscript, we also presented a methodology for developing acoustic models and language models to facilitate speech recognition in Fongbe. In this study, it was proposed and evaluated an acoustic modeling based on grapheme (since the Fongbe don't have phonetic dictionary) and also the impact of tonal pronunciation on the performance of a Fongbe ASR system. Finally, the written and oral resources collected for Fongbe and experimental results obtained for each aspect of an ASR chain in Fongbe validate the potential of the methods and algorithms that we proposed.

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