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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.
211

Le service minimum - Les services essentiels : approches française et québécoise.

Fontaine, Laurence 29 November 2004 (has links) (PDF)
Il n'existe plus de grève dans les services publics sans que soit évoqué, voire réclamé ou exigé le service minimum. Le droit français n'offre qu'une législation très parceIlaire et floue en la matière. Malgré de nombreuses propositions de loi, le législateur fait preuve d'inertie. Cette attitude s'explique notamment par la grande difficulté technique de la tâche imposant de concilier les deux principes de valeur constitutionneIle que sont le droit de grève et la continuité des services publics. Cette étude tend à mettre en exergue les interrogations relatives au service minimum et s'efforce de déceler la solution qui serait la mieux adaptée dans le système juridique fiançais. Afin de donner plus de relief à la recherche, le choix a été fait de l'aborder en s'inspirant du droit étranger. Le modèle choisi est originaire du Canada, et plus exactement du Québec. Il bénéficie d'un recul d'une vingtaine d'années et offre de ce fait, une expérience riche d'enseignements. La création d'un service minimum applicable aux services publics exige une analyse tant de la notion que de sa mise en oeuvre. Concrètement, il s'agit d'identifier les fondements du service minimum, de délimiter son champ d'application mais aussi de le définir en termes qualitatif et quantitatif, d'envisager sa mise en oeuvre par la voie négociée avec des acteurs spécifiques et de présenter les moyens permettant d'assurer son effectivité.
212

Fria och öppna programvaror inom kommunal verksamhet : Vägen mot öppna standarder? / Free- and open source software in municipalities : The way towards open standards?

Hanson, Malin, Larsson, Mikael January 2009 (has links)
<p>This report deals with the attitudes within municipalities of open source software and open standards and if open source software may be an option to gain open standards. The aim has been to find out if open source software and open standards would be able to solve the lock-in problems that municipalities have against proprietary software. The study is conducted as an exploratory, inductive and qualitative study with depth interviews of subjectively selected informants as data collection method. A literature review has also been implemented by the relevant books and articles. Some economic determinants of municipalities to make use of open source software have not been considered in this study. The informants used in this study are all IT managers in a Swedish municipality and our key informants have been selected in a subjective manner based on the expertise they have in the subject. The conclusions drawn were that municipalities have been difficult to define standards and open standards, and that they do not automatically see the connection between open standards and open software. They also see different areas of interest for standardization.</p> / <p>Denna rapport tar upp kommuners inställning till öppna program och öppna standarder och om öppen programvara kan vara ett alternativ för att få öppna standarder. Syftet har varit att ta reda på om öppna program och öppna standarder skulle kunna lösa de problem som kommuner har med inlåsningar mot proprietär programvara. Studien är genomförd som en explorativ, induktiv och kvalitativ studie med djupintervju av subjektivt utvalda informanter som datainsamlingsmetod. En litteraturgranskning har också genomförts av relevanta böcker och artiklar. Några ekonomiska faktorer för kommuner att använda sig av öppen programvara har inte beaktats i denna studie. De informanter som använts i denna studie är alla ITchefer inom någon svensk kommun och nyckelinformanterna har valts ut på ett subjektivt sätt utifrån den expertkunskap de besitter inom ämnet. Slutsatserna som drogs var att kommuner har svårt att definiera standarder och öppna standarder, och att de inte med automatik ser kopplingen mellan öppna standarder och öppen programvara. De ser också olika områden som intressanta för en standardisering.</p>
213

Structure-Function Relationships of Pi Class Glutathione Transferase Studied by Protein Engineering

Hegazy, Usama M. January 2006 (has links)
<p>The glutathione transferases (GSTs) represent a superfamily of dimeric proteins involved in cellular detoxication by catalyzing the nucleophilic addition of the reduced glutathione (GSH) to the hydrophobic electrophiles. The present work focuses on the functional role of the conserved structures of GSTP1-1. The lock-and-key motif is a highly conserved hydrophobic interaction in the subunit interface of Pi, Mu, and Alpha class GSTs. The key residue (Tyr<sup>50</sup> in hGSTP1-1) of one subunit is wedged into a hydrophobic pocket of the neighboring subunit. The heterodimer GSTP1/Y50A was constructed from the fully active wild-type GSTP1-1 and the nearly inactive Y50A in order to study how an essentially inactive subunit influences the activity of the neighboring subunit. The results illuminate the vital role of the lock-and-key motif in modulating the GSH binding and the rate of catalysis. Additionally, the two active sites of the dimeric enzyme work synergistically. An observed water network, in hGSTP1-1 structures, connects the two active sites, thereby offering a mechanism for communication between the two active sites.</p><p>Cys<sup>48</sup> and Tyr<sup>50</sup> were targeted by mutations and chemical modifications for understanding how the α2 loop residues modulate GSH binding and catalysis. The replacement of Tyr<sup>50</sup> with different unnatural amino acids showed that the nature of the key residue side-chain influences the interaction with the lock structure and, consequently, the catalytic activity. The K<sub>M</sub><sup>GSH</sup>, GSH affinity and protein stability can be modulated by fitting key residue into the lock cavity of the neighbor subunit and, consequently, restriction of the flexibility of the α2 loop. Optimization of the interaction between the key residue and the lock-cavity increases k<sub>cat</sub>. Also, the crystal structure of the Cys-free variant was determined. The result indicated that Cys<sup>48</sup> restricts the flexibility of the α2 loop by interacting with surrounding residues and, consequently, contributes to GSH binding and protein stability.</p>
214

Penser et gérer l'innovation en agriculture à l'heure du génie génétique : contributions d'une approche systémique d'innovations scientifiques dans deux filières agroalimentaires wallonnes pour l'évaluation, la gestion et les politiques d'innovation

Vanloqueren, Gaëtan 27 June 2007 (has links)
Les organismes génétiquement modifiés (OGM) suscitent en Europe une intense controverse depuis le milieu des années nonante, qui s'est cristallisée sur les risques pour la santé et l'environnement. Cette thèse postule que les OGM nous posent des questions plus larges sur l'innovation. Est-il par exemple possible d'évaluer la pertinence d'innovations, comme celle des OGM, pour tendre vers une meilleure politique et gestion de l'innovation ? Une approche systémique a été développée pour progresser sur cette question. Elle poursuit trois axes: la compréhension de problèmes agronomiques, des stratégies actuelles pour les gérer et des possibilités d'innovations pour les résoudre à l'horizon 2015-2020. La partie empirique est basée sur des études de cas de couples problème/innovations dans deux filières agroalimentaires. Il s'agit de maladies problématiques en arboriculture fruitière (pommier) et en grandes cultures (froment d'hiver). Les données de quatre composantes sont intégrées : entretiens semi-dirigés, observation participante, revue de la littérature scientifique et analyse de la littérature grise des filières. La gestion de l'innovation dans les filières est caractérisée par une vision de l'innovation à géométrie variable et par des situations de verrouillage technologique (lock-in). Sur un plan conceptuel, on peut distinguer dans la recherche agronomique plusieurs voies d'innovations (trajectoires technologiques) qui poursuivent des logiques distinctes et sont influencées par les déterminants d'innovation. Sur le plan méthodologique, des améliorations des méthodes d'évaluation des innovations sont avancées. Enfin, plusieurs politiques d'innovation adaptées sont proposées (comparaison des choix technologiques, prospective par scénarios). Cette recherche aboutit à une réflexion sur les sciences agronomiques et à la mise en débat d'un nouveau champ disciplinaire : l'agronomie politique. Les propositions visent à ré-encastrer l'innovation dans les enjeux écologiques contemporains et dans les projets politiques et aspirations citoyennes.
215

A Concurrency and Time Centered Framework for Certification of Autonomous Space Systems

Dechev, Damian 2009 December 1900 (has links)
Future space missions, such as Mars Science Laboratory, suggest the engineering of some of the most complex man-rated autonomous software systems. The present process-oriented certification methodologies are becoming prohibitively expensive and do not reach the level of detail of providing guidelines for the development and validation of concurrent software. Time and concurrency are the most critical notions in an autonomous space system. In this work we present the design and implementation of the first concurrency and time centered framework for product-oriented software certification of autonomous space systems. To achieve fast and reliable concurrent interactions, we define and apply the notion of Semantically Enhanced Containers (SEC). SECs are data structures that are designed to provide the flexibility and usability of the popular ISO C++ STL containers, while at the same time they are hand-crafted to guarantee domain-specific policies, such as conformance to a given concurrency model. The application of nonblocking programming techniques is critical to the implementation of our SEC containers. Lock-free algorithms help avoid the hazards of deadlock, livelock, and priority inversion, and at the same time deliver fast and scalable performance. Practical lock-free algorithms are notoriously difficult to design and implement and pose a number of hard problems such as ABA avoidance, high complexity, portability, and meeting the linearizability correctness requirements. This dissertation presents the design of the first lock-free dynamically resizable array. Our approach o ers a set of practical, portable, lock-free, and linearizable STL vector operations and a fast and space effcient implementation when compared to the alternative lock- and STM-based techniques. Currently, the literature does not offer an explicit analysis of the ABA problem, its relation to the most commonly applied nonblocking programming techniques, and the possibilities for its detection and avoidance. Eliminating the hazards of ABA is left to the ingenuity of the software designer. We present a generic and practical solution to the fundamental ABA problem for lock-free descriptor-based designs. To enable our SEC container with the property of validating domain-specific invariants, we present Basic Query, our expression template-based library for statically extracting semantic information from C++ source code. The use of static analysis allows for a far more efficient implementation of our nonblocking containers than would have been otherwise possible when relying on the traditional run-time based techniques. Shared data in a real-time cyber-physical system can often be polymorphic (as is the case with a number of components part of the Mission Data System's Data Management Services). The use of dynamic cast is important in the design of autonomous real-time systems since the operation allows for a direct representation of the management and behavior of polymorphic data. To allow for the application of dynamic cast in mission critical code, we validate and improve a methodology for constant-time dynamic cast that shifts the complexity of the operation to the compiler's static checker. In a case study that demonstrates the applicability of the programming and validation techniques of our certification framework, we show the process of verification and semantic parallelization of the Mission Data System's (MDS) Goal Networks. MDS provides an experimental platform for testing and development of autonomous real-time flight applications.
216

Structure-Function Relationships of Pi Class Glutathione Transferase Studied by Protein Engineering

Hegazy, Usama M. January 2006 (has links)
The glutathione transferases (GSTs) represent a superfamily of dimeric proteins involved in cellular detoxication by catalyzing the nucleophilic addition of the reduced glutathione (GSH) to the hydrophobic electrophiles. The present work focuses on the functional role of the conserved structures of GSTP1-1. The lock-and-key motif is a highly conserved hydrophobic interaction in the subunit interface of Pi, Mu, and Alpha class GSTs. The key residue (Tyr50 in hGSTP1-1) of one subunit is wedged into a hydrophobic pocket of the neighboring subunit. The heterodimer GSTP1/Y50A was constructed from the fully active wild-type GSTP1-1 and the nearly inactive Y50A in order to study how an essentially inactive subunit influences the activity of the neighboring subunit. The results illuminate the vital role of the lock-and-key motif in modulating the GSH binding and the rate of catalysis. Additionally, the two active sites of the dimeric enzyme work synergistically. An observed water network, in hGSTP1-1 structures, connects the two active sites, thereby offering a mechanism for communication between the two active sites. Cys48 and Tyr50 were targeted by mutations and chemical modifications for understanding how the α2 loop residues modulate GSH binding and catalysis. The replacement of Tyr50 with different unnatural amino acids showed that the nature of the key residue side-chain influences the interaction with the lock structure and, consequently, the catalytic activity. The KMGSH, GSH affinity and protein stability can be modulated by fitting key residue into the lock cavity of the neighbor subunit and, consequently, restriction of the flexibility of the α2 loop. Optimization of the interaction between the key residue and the lock-cavity increases kcat. Also, the crystal structure of the Cys-free variant was determined. The result indicated that Cys48 restricts the flexibility of the α2 loop by interacting with surrounding residues and, consequently, contributes to GSH binding and protein stability.
217

Survival of the Unfit : Path Dependence and the Estonian Oil Shale Industry

Holmberg, Rurik January 2008 (has links)
Estonia is the only country in the world, which is totally dependent on oil shale in its energy system. Although this fossil fuel exists in enormous quantities around the world, it has so far not been utilized on a larger scale. The reasons for this have been both economic and, in recent times, ecological. It can therefore be argued that in most cases, oil shale represents an inferior solution compared to other energy sources. This work examines why a technology utilizing oil shale has developed in Estonia and why Estonia appears not to be in a position to switch to other energy sources. In this work it is claimed that oil shale actually has been an appropriate solution to short-term concerns, despite the fact that its long-term drawbacks have been identified. These circumstances led to path dependence. Once the technology was in place, it advanced along its learning curve producing a satisfactory outcome, but not an optimal one. However, this situation has been accepted due to the extremely turbulent institutional environment Estonia has undergone in the 20th century. In Sweden, a somewhat similar (but smaller) oil shale industry was shut down in the 1960s because of poor economic performance, but also because of the competition from other energy sources. Such competition did not take place in Estonia, in part due to the specific institutional set-up of the Soviet Union. This made it possible for the Estonian oil shale industry to develop further, causing the present lock-in. Today the existing infrastructure, the knowledge-base, and the particular socio-political circumstances of Estonia effectively prevent change. Furthermore, it is argued that because there was only little oil shale-related technology developed outside Estonia, most technology had to be developed domestically. This in turn has forced the Estonian oil shale industry to make several highly inconvenient alliances in order to gain room to manoeuvre. Partially as a result of this, there is today wide-spread scepticism towards the industry, but no exit in sight in the foreseeable future. One purpose of this work is to contribute to a broader understanding why human societies have become dependent on fossil fuels and to extend our knowledge on where to search for an exit.
218

Soporte arquitectónico a la sincronización imparcial de lectores y escritores en computadores paralelos

Vallejo Gutiérrez, Enrique 10 June 2010 (has links)
La evolución tecnológica en el diseño de microprocesadores ha conducido a sistemas paralelos con múltiples hilos de ejecución. Estos sistemas son más difíciles de programar y presentan overheads mayores que los sistemas uniprocesadores tradicionales, que pueden limitar su rendimiento y escalabilidad: sincronización, coherencia, consistencia y otros mecanismos requeridos para garantizar una ejecución correcta. La programación paralela tradicional se basa en primitivas de sincronización como barreras y locks de lectura/escritura, con alta tendencia a fallos de programación. La Memoria Transaccional (TM) oculta estos problemas de sincronización al programador; sin embargo, múltiples sistemas TM aún se basan en locks, y se beneficiarían de una implementación eficiente de los mismos.Esta tesis presenta nuevas técnicas hardware para acelerar la ejecución de estos programas paralelos. Proponemos un sistema TM híbrido basado en locks de lectura/escritura, que minimiza los overheads del software cuando la aceleración hardware está presente. Desarrollamos un mecanismo para garantizar fairness entre transacciones hardware y software. Introducimos un mecanismo distribuido de aceleración de locks de lectura/escritura, llamado Lock Control Unit. Finalmente, proponemos una organización de multiprocesadores basadas en Kilo-Instruction Processors que garantiza Consistencia Secuencial y permite especulación en secciones críticas. / Technological evolution in microprocessor design has led to parallel systems with multiple execution threads. These systems are more difficult to program and present higher performance overheads than the traditional uniprocessor systems, what may limit their performance and scalability: synchronization, coherence, consistency and other mechanisms required to guarantee a correct execution. Traditional parallel programming is based on synchronization primitives such as barriers, critical sections and reader/writer locks, highly prone to programming errors. Transactional Memory (TM) removes the synchronization problems from the programmer. However, many TM systems still rely on reader/writer locks, and would get benefited from an efficient implementation.This thesis presents new hardware techniques to accelerate the execution of such parallel programs. We propose a Hybrid TM system based on reader/writer locks, which minimizes the software overheads when acceleration hardware is present, still allowing for correct software-only execution. We propose a mechanism to guarantee fairness between hardware and software transactions is provided. We introduce a low-cost distributed mechanism named the Lock Control Unit to handle fine-grain reader-writer locks. Finally, we propose an organization of a mutiprocessor based on Kilo-Instruction Processors, which guarantees Sequential Consistency while allowing for speculation in critical sections.
219

The System-on-a-Chip Lock Cache

Akgul, Bilge Ebru Saglam 12 April 2004 (has links)
In this dissertation, we implement efficient lock-based synchronization by a novel, high performance, simple and scalable hardware technique and associated software for a target shared-memory multiprocessor System-on-a-Chip (SoC). The custom hardware part of our solution is provided in the form of an intellectual property (IP) hardware unit which we call the SoC Lock Cache (SoCLC). SoCLC provides effective lock hand-off by reducing on-chip memory traffic and improving performance in terms of lock latency, lock delay and bandwidth consumption. The proposed solution is independent from the memory hierarchy, cache protocol and the processor architectures used in the SoC, which enables easily applicable implementations of the SoCLC (e.g., as a reconfigurable or partially/fully custom logic), and which distinguishes SoCLC from previous approaches. Furthermore, the SoCLC mechanism has been extended to support priority inheritance with an immediate priority ceiling protocol (IPCP) implemented in hardware, which enhances the hard real-time performance of the system. Our experimental results in a four-processor SoC indicate that SoCLC can achieve up to 37% overall speedup over spin-lock and up to 48% overall speedup over MCS for a microbenchmark with false sharing. The priority inheritance implemented as part of the SoCLC hardware, on the other hand, achieves 1.43X speedup in overall execution time of a robot application when compared to the priority inheritance implementation under the Atalanta real-time operating system. Furthermore, it has been shown that with the IPCP mechanism integrated into the SoCLC, all of the tasks of the robot application could meet their deadlines (e.g., a high priority task with 250us worst case response time could complete its execution in 93us with SoCLC, however the same task missed its deadline by completing its execution in 283us without SoCLC). Therefore, with IPCP support, our solution can provide better real-time guarantees for real-time systems. To automate SoCLC design, we have also developed an SoCLC-generator tool, PARLAK, that generates user specified configurations of a custom SoCLC. We used PARLAK to generate SoCLCs from a version for two processors with 32 lock variables occupying 2,520 gates up to a version for fourteen processors with 256 lock variables occupying 78,240 gates.
220

A Concurrency and Time Centered Framework for Certification of Autonomous Space Systems

Dechev, Damian 2009 December 1900 (has links)
Future space missions, such as Mars Science Laboratory, suggest the engineering of some of the most complex man-rated autonomous software systems. The present process-oriented certification methodologies are becoming prohibitively expensive and do not reach the level of detail of providing guidelines for the development and validation of concurrent software. Time and concurrency are the most critical notions in an autonomous space system. In this work we present the design and implementation of the first concurrency and time centered framework for product-oriented software certification of autonomous space systems. To achieve fast and reliable concurrent interactions, we define and apply the notion of Semantically Enhanced Containers (SEC). SECs are data structures that are designed to provide the flexibility and usability of the popular ISO C++ STL containers, while at the same time they are hand-crafted to guarantee domain-specific policies, such as conformance to a given concurrency model. The application of nonblocking programming techniques is critical to the implementation of our SEC containers. Lock-free algorithms help avoid the hazards of deadlock, livelock, and priority inversion, and at the same time deliver fast and scalable performance. Practical lock-free algorithms are notoriously difficult to design and implement and pose a number of hard problems such as ABA avoidance, high complexity, portability, and meeting the linearizability correctness requirements. This dissertation presents the design of the first lock-free dynamically resizable array. Our approach o ers a set of practical, portable, lock-free, and linearizable STL vector operations and a fast and space effcient implementation when compared to the alternative lock- and STM-based techniques. Currently, the literature does not offer an explicit analysis of the ABA problem, its relation to the most commonly applied nonblocking programming techniques, and the possibilities for its detection and avoidance. Eliminating the hazards of ABA is left to the ingenuity of the software designer. We present a generic and practical solution to the fundamental ABA problem for lock-free descriptor-based designs. To enable our SEC container with the property of validating domain-specific invariants, we present Basic Query, our expression template-based library for statically extracting semantic information from C++ source code. The use of static analysis allows for a far more efficient implementation of our nonblocking containers than would have been otherwise possible when relying on the traditional run-time based techniques. Shared data in a real-time cyber-physical system can often be polymorphic (as is the case with a number of components part of the Mission Data System's Data Management Services). The use of dynamic cast is important in the design of autonomous real-time systems since the operation allows for a direct representation of the management and behavior of polymorphic data. To allow for the application of dynamic cast in mission critical code, we validate and improve a methodology for constant-time dynamic cast that shifts the complexity of the operation to the compiler's static checker. In a case study that demonstrates the applicability of the programming and validation techniques of our certification framework, we show the process of verification and semantic parallelization of the Mission Data System's (MDS) Goal Networks. MDS provides an experimental platform for testing and development of autonomous real-time flight applications.

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