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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.
21

Alternativas de transporte rodo-marítimo na distribuição de cargas frigoríficas no Brasil / Road-waterway transportation alternatives in the distribution of reefer cargo in Brazil

Rafael José Rorato 22 August 2003 (has links)
Esta pesquisa investiga alternativas de transporte de cargas frigoríficas entre fábricas e centros de distribuição, avaliando as possíveis vantagens econômicas que resultariam do transporte intermodal rodo-hidroviário de contêineres ISO e do uso da CVC (Combinação de Veículo Carga) do tipo 3S3B3 - cavalo mecânico de três eixos mais dois semi-reboques de três eixos unidos por uma conexão do tipo B com PBTC de 74t, em relação ao cenário atual de transporte rodoviário porta-a-porta com a CVC do tipo 2S3 – cavalo mecânico de dois eixos com um semi-reboque de três eixos de 41,5t de PBTC. Com o auxílio de um Sistema de Informações Geográficas (TransCAD) dimensiona-se a frota e elabora-se um modelo de custos de transporte na rede de rotas para diversos cenários alternativos. As tarifas de pedágios das principais concessionárias de rodovias brasileiras e as tarifas portuárias dos portos considerados no modelo serviram como fonte de informações para a criação de mapas temáticos, rotas de caminho mínimo e a obtenção do custo por tonelada transportada. Conclui-se, através da análise dos resultados obtidos, que existem potenciais ganhos econômicos da alternativa de transporte intermodal rodo-marítimo, associado a CVC 3S3B3 – bitrem com implemento porta-contêineres, no acesso aos portos e no trajeto do porto ao centro de distribuição em relação à tecnologia de transporte utilizada atualmente, de transporte rodoviário porta-a-porta com a CVC 2S3 – semi-reboque com implemento rodoviário baú frigorífico e capacidade de carga de 26 paletes padrão PBR. Conclui-se também que a tecnologia do tipo 3S3B3 com baú frigorífico e capacidade de carga de 40 paletes oferece aos transportadores uma alternativa que, na grande maioria das rotas estudadas, é mais competitiva que a integração modal rodo-hidroviária. / This research investigates transportation alternatives between industries and distribution centers by evaluating the possible advantages of the road-waterway intermodal transport of ISO containers and the use of a LCV-Long Combination Vehicle of the 3S3B3 type – a tractor plus two semi-trailers linked by a B-train connection and 74t of GVW, in relation to the present roadway house-to-house operating scenario using a five axles semi-trailer of the 2S3 type and 41,5t of GVW. Using a Geographic Information System (TransCAD) the fleet size and the operating costs of the transportation network are calculated. For different alternative scenarios tolls charged by the brasilian private road administration partnership and current port rates are used in the model, and served as the basis to elaborate the thematic maps, minimum cost routes and costs per transported ton. From the analysis of the results it is concluded that the intermodal road-waterway alternative, associated to the transport of containers to the ports and from the ports to the distribution centers using the 3S3B3 with two container flatbeds, offers potencial economic gains in relation to the present technology using the house-to-house road transport with the 2S3 and a reefer trailer for 26 PBR pallets. It is also concluded that the 3S3B3 technology with 2 reefer units and capacity of 40 PBR pallets offers an alternative to the transportation industry that outperforms the road-waterway intermodal integration on most studied routes.
22

Distributed frequent subgraph mining in the cloud

Aridhi, Sabeur 29 November 2013 (has links) (PDF)
Recently, graph mining approaches have become very popular, especially in certain domains such as bioinformatics, chemoinformatics and social networks. One of the most challenging tasks in this setting is frequent subgraph discovery. This task has been highly motivated by the tremendously increasing size of existing graph databases. Due to this fact, there is urgent need of efficient and scaling approaches for frequent subgraph discovery especially with the high availability of cloud computing environments. This thesis deals with distributed frequent subgraph mining in the cloud. First, we provide the required material to understand the basic notions of our two research fields, namely graph mining and cloud computing. Then, we present the contributions of this thesis. In the first axis, we propose a novel approach for large-scale subgraph mining, using the MapReduce framework. The proposed approach provides a data partitioning technique that consider data characteristics. It uses the densities of graphs in order to partition the input data. Such a partitioning technique allows a balanced computational loads over the distributed collection of machines and replace the default arbitrary partitioning technique of MapReduce. We experimentally show that our approach decreases significantly the execution time and scales the subgraph discovery process to large graph databases. In the second axis, we address the multi-criteria optimization problem of tuning thresholds related to distributed frequent subgraph mining in cloud computing environments while optimizing the global monetary cost of storing and querying data in the cloud. We define cost models for managing and mining data with a large scale subgraph mining framework over a cloud architecture. We present an experimental validation of the proposed cost models in the case of distributed subgraph mining in the cloud.
23

Kalkulace nákladů jako východisko tvorby rozpočtů ve vybrané firmě / Costing as the Principle of the Budgeting Creation in the Selected Firm

Pittermannová, Martina January 2010 (has links)
The diploma thesis focuses on specification of cost calculation and budgets in selected company. Specifies cost models and costing system based on analysis of costs in bachelor thesis. Defines budgets, budget types and budget method and compares theoretical knowledge with reality in selected company. It contains suggestions of costs and budgets improvement.
24

Developing cost per flying hour factors for the operations and maintenance phase of the satellite life cycle

Kimbrough, Anthony K. January 2003 (has links)
Thesis (M.S.)--Air Force Institute of Technology, 2003. / Title from title screen (viewed July 1, 2004). "March 2003." Vita. "AFIT/GCA/ENV/03-04." "ADA415257"--URL. Includes bibliographical references (p. 71-74). Also issued in paper format.
25

An optimised QPSK-based receiver structure for possibly sparse data transmission over narrowband and wideband communication systems

Schoeman, Johan P. 24 August 2010 (has links)
In this dissertation an in-depth study was conducted into the design, implementation and evaluation of a QPSK-based receiver structure for application in a UMTS WCDMA environment. The novelty of this work lies with the specific receiver architecture aimed to optimise the BER performance when possibly sparse data streams are transmitted. This scenario is a real possibility according to Verd´u et al [1] and Hagenauer et al [2–6]. A novel receiver structure was conceptualised, developed and evaluated in both narrowband and wideband scenarios, where it was found to outperform conventional receivers when a sparse data stream is transmitted. In order to reach the main conclusions of this study, it was necessary to develop a realistic simulation platform. The developed platform is capable of simulating a communication system meeting the physical layer requirements of the UMTS WCDMA standard. The platform can also perform narrowband simulations. A flexible channel emulator was developed that may be configured to simulate AWGN channel conditions, frequency non-selective fading (either Rayleigh or Rician with a configurable LOS component and Doppler spread), or a full multipath scenario where each path has a configurable LOS component, Doppler spread, path gain and path delay. It is therefore possible to even simulate a complex, yet realistic, COST207-TU channel model. The platform is also capable of simulating MUI. Each interfering user has a unique and independent multipath fading channel, while sharing the same bandwidth. Finally, the entire platform executes all simulations in baseband for improved simulation times. The research outputs of this work are summarised below: <ul> <li>A parameter, the sparseness measure, was defined in order to quantify the level by which a data stream differs from an equiprobable data stream.</li> <li>A novel source model was proposed and developed to simulate data streams with a specified amount of sparseness.</li> <li>An introductory investigation was undertaken to determine the effect of simple FEC techniques on the sparseness of an encoded data stream.</li> <li>Novel receiver structures for both narrowband and wideband systems were proposed, developed and evaluated for systems where possibly sparse data streams may be transmitted.</li> <li>Analytic expressions were derived to take the effect of sparseness into account in communication systems, including expressions for the joint PDF of a BPSK branch, the optimal decision region of a detector in AWGN conditions as well as the BER performance of a communication system employing the proposed optimal receiver in both AWGN channel conditions as well as in flat fading channel conditions.</li> <li>Numerous BER performance curves were obtained comparing the proposed receiver structure with conventional receivers in a variety of channel conditions, including AWGN, frequency non-selective fading and a multipath COST207-TU channel environment, as well as the effect of MUI</li></ul>. AFRIKAANS : In hierdie verhandeling word ’n in-diepte studie gedoen rakende die ontwerp, implementasie en evaluasie van ’n KPSK-gebaseerde ontvanger struktuur wat in ’n UMTS WKVVT omgewing gebruik kan word. Die bydrae van hierdie werk lˆe in die spesifieke ontvanger argitektuur wat daarop mik om die BFT werksverrigting te optimeer wanneer yl data strome versend word. Hierdie is ’n realistiese moontlikheid volgens Verd´u et al [1] en Hagenauer et al [2–6]. ’n Nuwe ontvanger struktuur is gekonsepsualiseer, ontwikkel en evalueer vir beide noueband en wyeband stelsels, waar dit gevind is dat dit beter werksverrigting lewer as tradisionele ontvangers wanneer yl data strome versend word. Dit was nodig om ’n realistiese simulasie platform te ontwikkel om die belangrikste gevolgtrekkings van hierdie studie te kan maak. Die ontwikkelde platform is in staat om ’n kommunikasie stelsel te simuleer wat aan die fisiese laag vereistes van die UMTS WKVVT standaard voldoen. Die platform kan ook noueband stelsels simuleer. ’n Aanpasbare kanaal simulator is ontwikkel wat opgestel kan word om SWGR kanaal toestande, plat duining (beide Rayleigh of Ricies met ’n verstelbare siglyn komponent en Doppler verspreiding), sowel as ’n veelvuldige pad omgewing (waar elke unieke pad ’n verstelbare siglyn komponent, Doppler verspreiding, pad wins en pad vertraging het) te emuleer. Dit is selfs moontlik om ’n komplekse, maar steeds realistiese COST207-TU kanaal model te simuleer. Die platform het ook die vermo¨e om VGS te simuleer. Elke steurende gebruiker het ’n unieke en onafhanklike veelvuldige pad deinende kanaal, terwyl dieselfde bandwydte gedeel word. Laastens, alle simulasies van die platvorm word in basisband uitgevoer wat verkorte simulasie periodes verseker. Die navorsingsuitsette van hierdie werk kan as volg opgesom word: <ul> <li>’n Parameter, die ylheidsmaatstaf, is gedefin¨ýeer om dit moontlik te maak om die vlak waarmee die ylheid van ’n datastroom verskil van ’n ewekansige stroom te versyfer.</li> <li>’n Nuwe bronmodel is voorgestel en ontwikkel om datastrome met ’n spesifieke ylheid te emuleer.</li> <li>’n Inleidende ondersoek is onderneem om vas te stel wat die effek van VFK tegnieke op die ylheid van ’n enkodeerde datastroom is.</li> <li>Nuwe ontvanger strukture is voorgestel, ontwikkel en evalueer vir beide noueband en wyeband stelsels waar yl datastrome moontlik versend kan word.</li> <li>Analitiese uitdrukkings is afgelei om die effek van ylheid in ag te neem in kommunikasie stelsels. Uitdrukkings vir onder andere die gedeelte WDF van ’n BFVK tak, die optimale beslissingspunt van ’n detektor in SWGR toestande, sowel as die BFT werksverrigting van ’n kommunikasie stelsel wat van die voorgestelde optimale ontvangers gebruik maak, hetsy in SWGR of in plat duinende kanaal toestande.</li> <li>Talryke BFT werksverrigting krommes is verkry wat die voorgestelde ontvanger struktuur vergelyk met die konvensionele ontvangers in ’n verskeidenheid kanaal toestande, insluitend SWGR, plat duinende kanale en ’n veelvuldige pad COST207-TU kanaal omgewing, sowel as in die teenwoordigheid van VGS.</li></ul></p Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

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