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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

Variations of classical extremal graph theoretical problems: Moore bound and connectivity

Tang, Jianmin January 2009 (has links)
Research Doctorate - Doctor of Philosophy (PhD) / Interconnection networks form an important research area which has received much attention, both in theoretical research and in practice. Design of interconnection networks is much concerned with the topology of networks. The topology of a network is usually studied in terms of extremal graph theory. Consequently, from the extremal graph theory point of view, designing the topology of a network involves various extremal graph problems. One of these problems is the well-known fundamental problem called the degree/diameter problem, which is to determine the largest (in terms of the number of vertices) graphs or digraphs of given maximum degree and given diameter. General upper bounds, called Moore bounds, exist for the largest possible order of such graphs and digraphs of given maximum degree ∆ (respectively, out-degree d) and diameter D. However, quite a number of open problems regarding the degree/diameter problem do still exist. Some of these problems, such as constructing a Moore graph of degree ∆ = 57 and diameter D = 2, have been open for over 50 years. Another extremal graph problem regarding the design of the topology of a network is called the construction of EX graphs, which is to obtain graphs of the largest size (in terms of the number of edges), given order and forbidden cycle lengths. In this thesis, we obtain large graphs whose sizes either improve the lower bound of the size of EX graphs, or even reach the optimal value. We deal with designing the topology of a network, but we are also interested in the issue of fault tolerance of interconnection networks. This leads us to another extremal graph problem, that is, connectivity. In this thesis, we provide an overview of the current state of research in connectivity of graphs and digraphs. We also present our contributions to the connectivity of general regular graphs with small diameter, and the connectivity of EX graphs.
2

VEHICLE NAVIGATION & LOCATION SYSTEM BASED ON DGPS/INS/GIS INTEGRATED TECHNOLOGY

Pingfang, Zheng, Qishan, Zhang, Lung, Cheng Lee 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / With the rapid development of intelligent transport system in the world during the past few years, it promotes some navigation & location technology to a wide application especially in the car application. This paper firstly introduces some kinds of navigation & location systems and then analyzes the advantage and disadvantage of each system. On the basis of integrating every system and considering the high accuracy which can be achieved by adopting the technology based on DGPS (Differential Global Position System) at present, vehicle navigation & location system based on DGPS/INS/GIS integrated technology is put forward. The propound of this system shortens the distance between academic plan and real application greatly, and it provides a high accuracy and high reliability navigation & location system for traffic department and some car manufacturing Inc. In addition, this system is also provided with a friendly interface that makes it very easy to the manipulator or the user. The emphasis of this paper is put on the hardware and software of this system through introducing the system performance, the system component and the system software, and the characteristic of each module that makes up the whole system. The propound of the vehicle navigation & location system based on DGPS/INS/GIS integrated technology is a new attempt for development of intelligent transport system in our country, it will be sure to accelerate the process of our intelligent transport system.
3

Sistema de leito de drenagem e sedimentador como solução para redução de volume de lodo de decantadores e reuso de água de lavagem de filtros.

Fontana, Antonio Osmar 27 February 2004 (has links)
Made available in DSpace on 2016-06-02T20:00:51Z (GMT). No. of bitstreams: 1 DissAOF.pdf: 6243442 bytes, checksum: ee1b36639019670cbb0ec3ede6df6bcd (MD5) Previous issue date: 2004-02-27 / Water supply systems utilize, in most cases, conventional Water Treatment Plants (WTPs). These plants use alum and ferric salts in their coagulation process, and produce residues (sludge) mainly in filter systems and decanter tanks. The produced residues may be toxic to man and are usually disposed of on environment without any kind of treatment, therefore causing pollution. They present fluid characteristic with low solid content and great amount of water. Such characteristic hampers its transportation and proper disposal. The Cardoso plant used to fit the profile of pollutant, dumping its untreated sludge directly into a nearby stream. As a solution to this problem a system with a drainage bed for the sludge from decanter tank and a sedimentation tank for the backwash water from filters have been built. The system was built within the plant area itself. The drainage bed consists of a brick tank with a gravel layer support coated with a geotextile. The solid mass from the dewatered sludge showed adequate conditions as far as characteristics necessary for its final transportation and proper disposal. The water drained from sludge (effluent) is sent to the sedimentation tank. The turbidity, solids and COD were greatly reduced. The system was designed for a less than 30 days utilization period. The sedimentation tank consists of a fiberglass vase installed in a position that allows it to also receive the effluent from the drainage bed. The clarified water is recirculated to the influent of the water treatment plant and the solids are pumped to the drainage bed together the sludge from decanter tank. The system s operation does not require much labor and equipment. The aim of the research carried out was to design and analyze the drainage bed behavior according to prototype developed in the PROSAB 2 research Tema IV, integrated with Sedimentation Tank. Such integrated technology is an effective solution for the great majority of Water Treatment Plants with available areas. It is recommended that such system (Drainage bed and Sedimentation Tank) to be implemented should be always arranged to properly each individual Water Treatment Plant. Further studies should be also made on alternative of throwing clarified water straight from decanter tank to filters before dumping the sludge into drainage bed. / Os sistemas de abastecimento utilizam, na maioria, as Estações de Tratamento de Água (ETAs) convencionais. Essas estações utilizam em seu processo de coagulação sais de ferro ou de alumínio e produzem resíduos (lodos), principalmente, nos decantadores e filtros. Os resíduos produzidos podem ser tóxicos ao homem e normalmente são dispostos sem nenhum tipo de tratamento no meio ambiente causando poluição. Apresentam característica fluida com baixos teores de sólidos e grande quantidade de água. Essa característica dificulta seu manejo para transporte e disposição adequada. A ETA Cardoso, se enquadrava no perfil de poluidora lançando seus resíduos sem tratamento diretamente no corpo d água existente nas proximidades. Como solução para este problema foi implantado um sistema constituído de Leito de Drenagem para os lodos de decantadores e Sedimentador para as águas de lavagem de filtros. O sistema foi construído na própria área da ETA. O Leito de drenagem é constituído de um tanque em alvenaria e meio drenante com camada suporte de brita recoberto com manta geotextil. A massa final de sólido do lodo desaguado apresentou condição suficiente para manejo de retirada, transporte e disposição. O drenado foi encaminhado ao Sedimentador para reuso. Apresentou grande redução de turbidez, sólidos e DQO. O sistema foi projetado para um período de utilização inferior a 30 dias. O Sedimentador é constituído de um tanque em fibra de vidro instalado em posição que possa receber também o drenado do leito de drenagem. A água clarificada do Sedimentador e o drenado do Leito de Drenagem são recirculadas para o início da ETA. Os sólidos sedimentados no Sedimentador são bombeados para o Leito de Drenagem juntamente com o lodo de decantador. A operação do sistema demanda pouca mão de obra e equipamentos. A pesquisa realizada teve como objetivo projetar e analisar o comportamento do Leito de Drenagem, de acordo com o protótipo desenvolvido na pesquisa do PROSAB 2 Tema IV, integrado com o Sedimentador. Essa tecnologia integrada se apresenta como solução efetiva para a grande maioria de ETAs com disponibilidade de área. É recomendado que sempre seja implantado o sistema (Leito de Drenagem e Sedimentador) em arranjos convenientes para cada ETA. A redução da área do Leito de Drenagem é função de estudos para lançamento da água clarificada dos decantadores diretamente para os filtros.

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