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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.
351

The Value of Information in Multi-Objective Missions

Brown, Shaun January 2008 (has links)
Master of Engineering (Research) / In many multi-objective missions there are situations when actions based on maximum information gain may not be the `best' given the overall mission objectives. In addition to properties such as entropy, information also has value, which is situationally dependent. This thesis examines the concept of information value in a multi-objective mission from an information theory perspective. A derivation of information value is presented that considers both the context of information, via a fused world belief state, and a system mission. The derived information value is used as part of the objective function for control of autonomous platforms within a framework developed for human robot cooperative control. A simulated security operation in a structured environment is implemented to test both the framework, and information value based control. The simulation involves a system of heterogeneous, sensor equipped Unmanned Aerial Vehicles (UAVs), tasked with gathering information regarding ground vehicles. The UAVs support an e ort to protect a number of important buildings in the area of operation. Thus, the purpose of the information is to aid the security operation by ensuring that security forces can deploy e ciently to counter any threat. A number of di erent local controllers using information based control are implemented and compared to a task based control scheme. The relative performance of each is examined with respect to a number of performance metrics with conclusions drawn regarding the performance and exibility of information value based control.
352

支援多租戶應用程式的SQL語句轉換機制 / A SQL rewriting mechanism for enabling multi-tenant applications

吳定威, Wu, Ding Wei Unknown Date (has links)
軟體即服務(Software as a Service, SaaS)是雲端運算環境下一種新興的服務模式,它的特色是將特定的應用軟體以共享軟硬體資源的方式供眾多的租戶(tenants)使用。因此,如何提供共用且有客制化功能的應用軟體就是SaaS模式的重要成功關鍵。本研究聚焦於資料庫層提供多租戶共用表格但有客制化功能的機制。讓開發人員延續一租戶一資料表的架構為基礎設計資料庫,透過SQL語句轉換機制,將SQL語句轉換為操作共享表格的語句執行,以大幅減化開發人員的工作。本研究包含兩個部份,一是資料綱要對應表(Schema Mapping Table),協助開發人員將單租戶資料庫架構轉換為塊狀表格(chunk table)的共用資料綱要方式;另一個是SQL語句自動轉換工具,透過剖面技術織入JDBC程式集中,在應用系統執行期間,將SQL語句,從一租戶一資料表寫法轉換為共享表格的方式執行。故只需將資料表改為共用架構即可使用,達到提升多租戶系統開發速度並提高資源使用率的目的。 / Software as a service (SaaS) is an emerging service model of cloud computing, which is characterized by providing software that charges on a usage basis over shared hardware and software resources for a large number of tenants to use. Therefore, how to provide shared tables and customization of the applications is an important key to success in the SaaS model. This study focuses on how to enable multi-tenancy on the database layer Developers can extend a private table structure-based application to a shared database one through the proposed SQL rewriting mechanism. This approach can greatly simplify the developer's work. Our approach consists of two parts, first is Schema Mapping Table that helps developers to convert single-tenant database architecture into the chunk table schema; another is SQL statement conversion tools that works by enhancing the JDBC library as an aspect in the AspectJ language. During the execution of the application, a SQL statement is rewritten from the private table based format into chunk table based statement. In this way, we are able to enhance an application with multitenant shared tables that improve resource utilization.
353

Efficace de diffusion de l'information sans fil multi-hop Réseaux.

Cho, Song Yean 22 September 2008 (has links) (PDF)
Many protocols and applications in wireless multi-hop networks indispensably use broad- casting to delivery messages to all nodes in a network. Wireless routing protocols such as DSR, AODV and ODRMP broadcast route discovery messages, and many application protocols exchange query and response messages by broadcasting. Hence, the efficiency of broadcasting is critical to efficiency of these wireless protocols. Efficient wireless broadcast- ing is a topic that this thesis studies where efficiency is measured by the total transmission number to broadcast one unit data to the whole network. The study is done in two ways: extending classical methods and utilizing a novel method, network coding. Classical broadcasting protocols are based on store-and-forward routing that views pack- ets as atomic objects and lets a node store incoming packets in its local queue for some delay, before forwarding one or several copies of the packets to its neighbors. Among the classical broadcast protocols, the simplest and most widely used broadcast protocol is pure flood- ing. Pure flooding reliably provides total coverage of a network, but causes redundancy of packets, resulting in unnecessary collisions, and enormous inefficiency. To combat this inef- ficiency, many efficient broadcast protocols have been studied using probabilistic algorithms such as a gossip protocol, or algorithms based on topology control such as a Multi-Point Relay (MPR) based protocol. These broadcast protocols have been successfully used in many wireless protocols standardized in IEEE 802.11 and IETF. One possible application of the broadcast protocols is wireless mesh networks standard- ized in 802.11Working Group S. The 802.11 mesh networks face challenges such as inefficient broadcasting of so-called associated station information that is partially updated; there ex- ists redundancy between newly updated data and already broadcasted data. This thesis addresses these challenges by introducing an Association Discovery Protocol (ADP) that is combined with MPR-based broadcasting and integrated with an extension of an Optimized Link State Routing (OLSR) protocol for the 802.11 mesh networks. The results of analysis with modeling and simulation show that the protocol effectively decreases control overhead. However, for continuous data traffic, there exists another possible broadcast solution, which could theoretically outperform the broadcast protocols with classical store-and-forward routing and would not require precise topology information. This solution is network coding. Theoretically, network coding enables an optimized solution for wireless broadcasting in a polynomial time, while it is NP-complete with classical store-and-forward routing and only approximation algorithms exist. Hence, broadcasting with network coding is, theoretically, at least as efficient as any other broadcasting. This thesis focuses on utilizing network coding specifically as a practical solution for efficient wireless broadcasting. For the practical solution, this thesis proposes simple al- gorithms based on intuitive rationale about optimal efficiency of wireless network coding. The efficiency of the proposed simple algorithms is theoretically analyzed, and proven to be asymptotically optimal. The efficiency also is experimentally analyzed and shown, in some examples, to outperform other broadcasting with classical store-and-forward routing. Finally, from these simple algorithms we derive a practical broadcasting protocol executing with a simple and efficient coding method (that is, random linear coding). In addition, we propose a simple novel method for real-time decoding that could be combined with the practical network coding broadcasting protocol.
354

Östersjömiljarderna - en studie i svensk partipolitik

Gustafsson, Peter January 2010 (has links)
<p>Syftet med uppsatsen är att analysera Gunnar Sjöbloms modell om programrealisering utifrån ett fall, Östersjömiljardprojektet, samt att följa upp modellen med aspekten om Multi-level governance. Detta görs med hjälp av tre frågeställningar. För att uppfylla syftet har jag med hjälp av en textanalys bearbetat material hämtat från Rikslex, Riksdagens arkiv, i form av propositioner, motioner, betänkande, och protokoll. Den teoretiska utgångspunkten har tagits ifrån Gunnar Sjöbloms modell som bygger på partistrategi i ett flerpartisystem. Partiernas främsta mål är att uppnå programrealisering. För att åstadkomma detta krävs inflytande på tre arenor: väljararenan, den interna arenan och den parlamentariska arenan.Östersjömiljardprojektet var ett förslag i sysselsättningspropositionen 1995 som byggde på att en miljard kronor skulle ingå i en fond avsatt för att främja svensk export inom områdena livsmedel, energi, ömsesidigt kunskapsutbyte, stärkt infrastruktur samt samarbete för att miljöskydd runt Östersjön. De områden som ingår i projektet är nordvästra Ryssland, Estland, Lettland, Litauen samt Polen. Resultatet visar att Sjöbloms modell är hållbar för det valda fallet. För att avgöra om det är ett fall av multi-level governance krävs ytterligare forskning på vilka påtryckningar utanför den politiska arenan som var betydande för beslutet.</p>
355

Decision Aid for Planning Local Energy Systems : Application of Multi-Criteria Decision Analysis

Catrinu, Maria January 2006 (has links)
<p>Planning is what sustains an energy system. It is a process of analysis and ongoing decision making about what resources and energy technologies to use when supplying energy to society. This research focuses on integrated energy systems, i.e. systems that are comprised of several energy carriers – electricity, gas, hot water - and energy distribution networks. The planning of these kinds of systems is a complex process, influenced by many factors, among which the most important are the availability of energy resources and the competition between different energy carriers in satisfying energy demand. During the last 10-20 years significant changes have taken place on the world energy scene, which have important implications for energy planning. Two main factors have triggered these changes. The first factor is the immediate need to address environmental changes or more generally, to take measures that are sustainable in the long run. Sustainability can be defined in many ways and in relation to different issues such as economic and ecologic development, reduction of greenhouse gases, responsible use of natural resources, social equity, etc. In recent years, an increased awareness of these issues has been observed at all levels of the society. The second factor is the deregulation of national energy sectors in more than 50 countries. This process brought changes in the ownership of different parts of the formerly integrated energy systems. New business opportunities were created in power generation, wholesale power/gas trading and energy retailing, while the energy infrastructures remained state owned or/and under regulatory control. The newly created energy markets (many of them international) have attracted both new players (power, oil and gas companies and financial institutions) together with the old ones (integrated utilities). In parallel with this vertical separation of national energy sectors, recent studies have shown a tendency for horizontal integration at the regional/company level. For instance, in order to reduce their overall business risk, companies prefer to participate in several segments of the energy value chain (in both regulated and non-regulated activities), and often across more than one fuel commodity, such as gas and electricity or district heating. In this context, the competition between different energy carriers in satisfying the end-use energy demand became obvious in economic as well as in technological and environmental terms. Traditionally, in integrated planning, this competition did not play a big role, since the same state entity made decisions at both national and regional levels. However, in the post-deregulation era it is no longer obvious who the planner is. In many cases, planning decision at local levels involve at least three main interest groups: energy companies (and/or other investors), the state and the local community. This thesis is motivated by the need to help planners to cope with the changes in concepts and values concerning the planning of local energy supply systems. This thesis has two aims. The first aim is to improve the understanding of what planning of local systems implies and how such a process can be structured. The second aim is to contribute to the development of decision support methodologies and tools that can cope with the needs in planning. For this purpose, the use of energy modelling and Multi- Criteria Decision Analysis has been studied.</p>
356

Damalini AB : ett företag i ständig utveckling

Asplind, Håkan January 2004 (has links)
No description available.
357

Resurshantering i Dual-core kluster

Gustafsson, Johan, Lingbrand, Mikael January 2008 (has links)
<p>Med den nya generationen processorer där vi har flera cpu-kärnor på ett chip, så ökas prestandan genom parallell exekvering. I denna rapport presenterar vi en omvärldsstudie om allmän multiprocessorteori där vi går igenom olika tekniker för både hårdvara och mjukvara. Vi har även utfört empiriska tester på ett datorkluster, där vi har testat de två olika programmen Fluent och CFX, som utför CFD beräkningar. För varje program så har tre modeller använts för simuleringar med varierande antal beräkningsnoder. Vi har undersökt vad som är mest lönsamt, att använda en eller båda CPU-kärnorna vid de olika simuleringarna. För att testa detta har vi kört simuleringar där vi har kört med en respektive två cpu-kärnor på beräkningsnoderna. Under simuleringarna har vi samlat in mätvärden som nätverk, minne och cpu-belastning för alla noder samt exekveringstider. Dessa värden har sedan sammanställts där vi ser att ju större en modell är desto mer lönar det sig att köra med en cpu-kärna. I endast ett av våra tester har det visat sig lönsamt att använda båda cpu-kärnorna. En formel har sedan utarbetats för att påvisa skillnaderna mellan olika antal processer med en respektive två cpu-kärnor per nod. Denna formel kan appliceras för att räkna ut den totala kostnaden per simulering med hjälp av årskostnaden för de noder och licenser som används.</p>
358

Fluoroionophores dérivés de la coumarine 343 : photophysique et étude de la complexation de cations alcalins et alcalino-terreux

Taziaux, Dorothée 09 September 2004 (has links)
Plusieurs fluoroionophores dérivés de la coumarine 343 ont été synthétisés. Leurs propriétés photophysiques et complexantes ont été déterminées dans l'acétonitrile. Ce sont des systèmes donneur-accepteur conjugués, où le cation interagit avec l'accepteur. Nous attendons donc des déplacements bathochromes des spectres d'absorption et d'émission. L'étude de C343-crown, -benzocrown et -dibenzocrown, dérivés de l'éther-couronne aza 15-crown-5, nous a permis de montrer que la rigidification de la cavité complexante permettait d'augmenter la sélectivité pour les cations alcalino-terreux par rapport aux alcalins. Les constantes de stabilité déterminées pour les complexes formés avec le magnésium ne varient presque pas lorsque la couronne est modifiée, ce qui suggère que cette dernière ne participe pas significativement à la complexation. L'étude des propriétés complexantes de C343-dieta et -dimeta, qui ne possèdent pas d'éther-couronne, nous permet de vérifier cette hypothèse. Afin d'augmenter la stabilité des complexes par la formation de semi-cryptates, deux sondes dérivées de l'éther-couronne diaza 18-crown-6, possédant 2 fluorophores, sont synthétisées. La présence de deux fluorophores permet d'observer des effets photophysiques supplémentaires, et d'obtenir des complexes environ 100 fois plus stables que ceux formés par les fluoroionophores dérivés de l'éther-couronne aza 15-crown-5. Nous avons pour certains fluoroionophores complété les résultats obtenus en absorption UV-visible et en fluorescence par des études en infra-rouge, en RMN du proton et du carbone et en spectrométrie de masse avec ionisation par électrospray (ESI-MS). Ces deux dernières techniques nous ont apporté des informations sur la structure des complexes formés, notamment sur la participation de la couronne et du solvant à la complexation.
359

Real-time Mosaic for Multi-Camera Videoconferencing

Klechenov, Anton, Gupta, Aditya Kumar, Wong, Weng Fai, Ng, Teck Khim, Leow, Wee Kheng 01 1900 (has links)
This paper describes a system for high resolution video conferencing. A number of camcorders are used to capture the video, which are then mosaiced to generate a wide angle panoramic view. Furthermore this system is made “real-time” by detecting changes and updating them on the mosaic. This system can be deployed on a single machine or on a cluster for better performance. It is also scalable and shows a good real-time performance. The main application for this system is videoconferencing for distance learning but it can be used for any high resolution broadcasting. / Singapore-MIT Alliance (SMA)
360

Traditional Inventory Models in an E-Retailing Setting: A Two-Stage Serial System with Space Constraints

Allgor, Russell, Graves, Stephen C., Xu, Ping Josephine 01 1900 (has links)
In an e-retailing setting, the efficient utilization of inventory, storage space, and labor is paramount to achieving high levels of customer service and company profits. To optimize the storage space and labor, a retailer will split the warehouse into two storage regions with different densities. One region is for picking customer orders and the other to hold reserve stock. As a consequence, the inventory system for the warehouse is a multi-item two-stage, serial system. We investigate the problem when demand is stochastic and the objective is to minimize the total expected average cost under some space constraints. We generate an approximate formulation and solution procedure for a periodic review, nested ordering policy, and provide managerial insights on the trade-offs. In addition, we extend the formulation to account for shipping delays and advanced order information. / Singapore-MIT Alliance (SMA)

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