Thesis (M.B.A.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 85-86).

Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2002. / Thesis advisor(s): Bert Lundy, Mike Tatom. Includes bibliographical references (p. 71-77). Also available online.

The issue of protecting a fiber communication system is of considerable concern mainly because of the fiber's capability of carrying a large amount of traffic. In this study, we are concerned with the role of topology in relation to the survivability and network cost. Studying three simple network topologies, the ring, hub and mesh topologies, the ring topology is found to have many advantages for high capacity communication systems. Combinations of the simple network topologies may be used to combine the advantages of each topology. A toroidal grid topology, which combines advantages of ring and mesh topologies, is described and evaluated. Analytic results shows that the toroidal grid achieves survivability with lower incremental costs compared to the ring topology. The analytical results are limited to simple geometric and uniform traffic models. A computer program is developed to analyze the performance of more realistic networks. The computer results show that the length of a network system is a major factor affecting the cost of the network. The idea of having a multiply interconnected ring system appears to be an attractive topology for long-distance applications. / Master of Science

Universal service is the focal point of the economic dilemma faced by the telecommunications industry. The advent of competition spurred by several regulatory rulings is forcing rates towards economic costs. It is feared that this movement or the erosion of the toll-to-local subsidy with concomitant increases in local prices severely threatens the concept of universal service. To adequately address these fears, accurate elasticity of demand estimates for telephone access are required. This thesis develops estimates of these demand elasticities for access. These estimates are derived consistently from an underlying theory of demand for access. Furthermore, the simultaneous access and class-of-service choice problems are addressed similarly. This consistent development facilitates model usage and interpretation. For example, the model provides the best available estimate for the size of the network externality. Taking into account the underlying demand theory and acknowledging the problems associated with the aggregated nature of the data set (census tract data from 1980 Census), a modified probit technique is developed to estimate the demand model. The estimation methodology is implemented using an iterative least square procedure. To analyze the reasonableness of the algorithm and procedure, a Monte Carlo study is performed. In addition, a jackknife technique is employed to estimate variances of coefficients when the standard measures are unavailable. The model results are used to analyze the effect of current policy decisions. For example, for a proposed doubling of access prices the demand for access elasticity is found to be quite small, about -.04. A welfare analysis is performed to discuss the costs and benefits associated with moving to cost-based rates. This analysis also provides the basis for rate recommendations to facilitate the transition to competition while attempting to preserve the concept of universal service.

Orientador: Ricardo Abid Castillo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-06T12:04:14Z (GMT). No. of bitstreams: 1 Iozzi_FabiolaLana_M.pdf: 3910334 bytes, checksum: 3fa383241f2c0fd658f4072c67afb45b (MD5) Previous issue date: 2006 / Resumo: A quebra do monopólio estatal em 1995 e a privatização propriamente dita poucos anos mais tarde, constituem os principais marcos do processo de reestruturação do sistema brasileiro de telecomunicações. Essa mudança na natureza dos agentes prestadores dos serviços de telecomunicações, antes estatais e agora privados, demandou a criação de instrumentos regulatórios que visam garantir a universalização e continuidade no que diz respeito ao serviço de telefonia fixa. A proposta de universalização tem como objetivo assegurar a oferta desse serviço básico para qualquer pessoa independentemente de sua localização ou condição sócio-econômica. Assim, as metas de universalização surgiram como uma espécie de garantia para a população frente ao processo de privatização do sistema de telecomunicações brasileiro. ssa proposta, porém, é baseada somente na expansão do número de linhas telefônicas instaladas o que não significa dizer que essas linhas estejam realmente sendo utilizadas. O uso desse serviço é condicionado ao pagamento de altas tarifas, o que impede o acesso de parcela da população, que não possui potencial econômico suficiente para arcar com tais custos. O Estado concede o oferecimento de um serviço básico para agentes privados e se exime do planejamento de um segmento estratégico. Se o Estado deve ter o comprometimento com a totalidade do território, os agentes privados comprometem-se apenas com a busca pelo lucro, o que em um país que revela tantas desigualdades torna-se um dado perverso. Desse modo, procuramos, neste trabalho, desvendar essa contradição a partir da análise do território brasileiro, pois este revela as conseqüências das ações políticas e a coerência com a realidade na qual estas se dão. Essa discussão se fará por meio da análise das transformações técnicas e normativas em curso no sistema de telecomunicações brasileiro, na busca de contribuir para a identificação dos rumos da universalização proposta para o serviço de telefonia fixa no Brasil / Abstract: The break in the State monopoly in 1995 and a few years later, the privatization properly said, constitute the main bases of the process of restructure of the Brazilian telecommunication system. This change in the nature of the telecommunication services render agents, in the past, being from the State and now private, demanded the creation of regulatory instruments that aim to warranty the universalization and continuity in what concerns to the fixed telephone system service. The proposal of universalization has as an aim to ensure the offer of this basic service for every person independently from his or her localization or social-economic condition. Thus, the goals of universalization came up as a kind of guarantee for the population front to the process of privatization of the Brazilian telecommunication system. However, this proposal is based only in the expansion of the number of installed telephone lines, what doesn¿t mean that those lines are really being used. The use of this service depends on the payment of high tariffs, which impedes the access of part of the population that doesn¿t have enough economic potential to afford such costs. The State concedes the offering of a basic service for private agents and releases itself from the planning of a strategic segment. If the State must have the commitment to the totality of the territory, the private agents commit themselves only to the seek for the profit, which in a country that reveals so much inequality, it turns into a wicked date. In this way, we tempt, in this work, to unmask this contradiction, from the analysis of the Brazilian territory, because this reveals the consequences of the political actions and the coherence to the reality in which they occur. This discussion will be achieved through the analysis of the technical and normative transformations occurring in the Brazilian telecommunication system, in the search for the contribution to the identification of the ways the proposed universalization for the fixed telephone system service in Brazil / Mestrado / Mestre em Geografia