Verification of access control systems against vulnerabilities has always been a challenging problem in the world of computer security. The complication of security policies in large- scale multi-agent systems increases the possible existence of vulnerabilities as a result of mistakes in policy definition. This thesis explores automated methods in order to verify temporal and epistemic properties of access control systems. While temporal property verification can reveal a considerable number of security holes, verification of epistemic properties in multi-agent systems enable us to infer about agents' knowledge in the system and hence, to detect unauthorized information flow. This thesis first presents a framework for knowledge-based verification of dynamic access control policies. This framework models a coalition-based system, which evaluates if a property or a goal can be achieved by a coalition of agents restricted by a set of permissions defined in the policy. Knowledge is restricted to the information that agents can acquire by reading system information in order to increase time and memory efficiency. The framework has its own model-checking method and is implemented in Java and released as an open source tool named \(\char{cmmi10}{0x50}\)\(\char{cmmi10}{0x6f}\)\(\char{cmmi10}{0x6c}\)\(\char{cmmi10}{0x69}\)\(\char{cmmi10}{0x56}\)\(\char{cmmi10}{0x65}\)\(\char{cmmi10}{0x72}\). In order to detect information leakage as a result of reasoning, the second part of this thesis presents a complimentary technique that evaluates access control policies over temporal-epistemic properties where the knowledge is gained by reasoning. We will demonstrate several case studies for a subset of properties that deal with reasoning about knowledge. To increase the efficiency, we develop an automated abstraction refinement technique for evaluating temporal-epistemic properties. For the last part of the thesis, we develop a sound and complete algorithm in order to identify information leakage in Datalog-based trust management systems.

Thesis (M.Ed. (Education)) - Rhodes University, 2008.

Thesis (M. A.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 152-157). Also available via the World Wide Web.

Thesis (Ph. D.)--Georgia Institute of Technology and Georgia State University, 2008. / Title from file title page. Philip P. Shapira (Georgia Tech), committee chair; Marco Ceccagnoli, Mary Frank Fox (Georgia Tech); Gregory B. Lewis, John P. Walsh (Georgia State), committee members. Electronic text (146 p. : col. ill., col maps) : digital, PDF file. Description based on contents viewed Sept. 17, 2008. Includes bibliographical references (p. 143-146).

Thesis (M.B.A.)--University of Hong Kong, 1995. / Includes bibliographical references.

Thesis (Ph. D.)--Technische Universiteit Delft, 1992. / In English with summary in Dutch. Includes bibliographical references (p. 221-236) and index.

Thesis (Ph. D.)--University of California, Berkeley, 1993. / Includes bibliographical references (leaves 248-265).

Thesis (Ph. D.)--University of Canterbury, 2005. / Typescript (photocopy). Includes bibliographical references (leaves 302-317). Also available via the World Wide Web.

Este trabalho de dissertação é um estudo sobre os aspectos relevantes tanto das tecnologias da informação quanto das estratégias na competitividade do sistema agroindustrial do leite, tendo como objetivo central, diagnosticar as barreiras e os fluxos de informações estratégicas existentes neste setor para uma avaliação nos micros, pequenos e médios laticínios para que estes se tornem mais competitivos. Inicialmente, é realizada uma breve descrição e caracterização de como se encontra o sistema agroindustrial do leite no âmbito econômico nacional, tornando assim, mais claro as razões pelas quais se torna necessário este estudo. O tema é, então, enfocado através da sistematização dos principais conceitos sobre estratégia e tecnologia da informação citados na literatura. Após, é enfocado de um modo geral, o cenário industrial brasileiro. Com isto, o suporte para um levantamento de dados específico sobre o sistema agroindustrial do leite está configurado; através de figuras e tabelas são mostrados dados estatísticos do mercado nacional e internacional e os motivos pelos quais o Brasil não é o primeiro no ranking mundial. Dados esses extraídos de autores. De posse desses dados, para a realização da pesquisa, caracterizou-se como sendo exploratória na consecução de seus objetivos e qualitativa para os procedimentos de coleta de dados. Com a aplicação de entrevistas estruturadas, através de um roteiro de perguntas elaboradas (utilizando-se do recurso das variáveis ambientais) chegou-se a um resultado. Com estes resultados obtidos pôde-se fazer uma comparação entre os autores pesquisados, e percebeu-se que, na pesquisa empírica, a caracterização dos laticínios se apresentam semelhantes a estes autores, ou seja, a ausência de uma fiscalização mais rígida compromete toda a cadeia produtiva do leite. O fator tecnologia da informação é essencial como estratégia competitiva, pois pôde-se notar nos médios laticínios ) a sua utilização em todos os departamentos, inclusive com ambientes intranet e extranet. Sendo considerada as restrições existentes na pesquisa, pode ser contatado que as estratégias e as tecnologias da informação dependem de outros fatores para impulsionar os micros e pequenos laticínios. / This dissertation work is a study on the important aspects so much of the technologies of the information as of the strategies in the competitiveness of the system agroindustrial of the milk, tends as central objective, to diagnose the barriers and the flows of existent strategic information in this section for an evaluation in the micro, small and medium dairy products for these they become more competitive. Initially, it is accomplished an abbreviation description and characterization of as is the system approach of the milk in the national economical ambit, turning like this, clearer the reasons for the which becomes necessary this study. The theme is, then, focused through the systematization of the principal concepts on strategy and technology of the information mentioned in the literature. After, it is focused in a general way, the Brazilian industrial scenery. With this, the support for a rising of data specific on the system approach of the milk is configured; through illustrations and tables are shown data statisticians of the national and international market and the reasons by the which Brazil is not the first in the world ranking. Data those extracted of authors. Of ownership of those data, for the accomplishment of the research, it was characterized as being exploratory in the attainment of your objectives and qualitative for the procedures of collection of data. With the application of structured interviews, through a route of elaborated questions (being used of the resource of the environmental variables) it was arrived to a result. With these obtained results it could be made a comparison among the researched authors, and it was noticed that, in the empiric research, the characterization of the dairy products comes similar to these authors, in other words, the absence of a more rigid fiscalization commits the whole productive chain of the milk. The factor technology of the information is essential as competitive strategy, because it could be noticed in the medium dairy products your use in all the departments, besides with atmospheres intranet and extranet. Being considered the existent restrictions in the research, it can be verified that the strategies and the technologies of the information depend on other factors to impel the micro and small dairy products.

Esta dissertação é fruto de uma pesquisa exploratória no âmbito da Seleção de Fornecedores de Serviços de Tecnologia da Informação (TI) e pretende identificar os principais procedimentos de avaliação e critérios de seleção utilizados para a escolha de empresas fornecedoras deste tipo de serviço. A pesquisa empírica contempla duas empresas multinacionais, dois grandes bancos e duas pequenas e médias empresas. O trabalho realiza uma revisão da bibliografia existente sobre o tema e questões a ele associadas. A partir desta revisão foi possível desenvolver o modelo de pesquisa. A metodologia de pesquisa utilizada foi o Estudo de Casos Múltiplos, o que permitiu ao pesquisador o aprofundamento em alguns aspectos do processo de seleção adotado pelas empresas para a escolha de fornecedores de serviços de TI. A pesquisa foi realizada com base em entrevistas feitas junto aos executivos ou gerentes de TI que atuam no processo de seleção, em seis empresas que já possuem contratos com fornecedores de serviços de TI. As entrevistas foram conduzidas segundo o roteiro elaborado a partir do modelo de pesquisa. / This theory accomplishes an exploratory research in the extent of the Selection of Suppliers of Services of Technology of the Information (IT) and it intends to identify the main evaluation procedures and selection criteria used for the choice of supplying companies of this service type. The empiric research contemplates two multinational companies, two great banks and two small and medium companies. The work accomplishes a revision of the existent bibliography on the theme and subjects to him associated. Starting from this revision it was possible to develop a research model. The methodology of used research was the Study of Multiple Cases, that allowed to the researcher go deeply in some aspects of the selection process adopted by the companies for the choice of suppliers of services of IT. The research was accomplished with base in interviews done with the executives or managers of IT that act in the selection process, in six companies that already possess contracts with suppliers of services of IT. The interviews were driven according to the guide elaborated from the research model.