• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 128
  • 68
  • 49
  • 30
  • 23
  • 19
  • 16
  • 12
  • 11
  • 10
  • 10
  • 5
  • 4
  • 4
  • 4
  • Tagged with
  • 420
  • 177
  • 128
  • 127
  • 125
  • 121
  • 61
  • 57
  • 53
  • 50
  • 47
  • 46
  • 31
  • 31
  • 31
  • 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.
61

O impacto da virtualização no desempenho de aplicações distribuídas baseadas em SOA e a sua influência nos modelos de desempenho / The impact of visualization on te performance of SOA-based applications and its influence on the performance models

Alves, Luís Cézar Darienzo 16 October 2013 (has links)
Esta tese de doutorado analisa o impacto gerado pela virtualização assistida por hardware, de terceira geração, no desempenho de aplicações baseadas em SOA do tipo CPU-bound e memory-intensive, bem como nas operações de marshalling e unmarshalling de mensagens SOAP executadas nas bibliotecas dos servidores de aplicação. A partir dessa análise, concluiu-se que os recursos disponibilizados pela plataforma de hardware, principalmente no gerenciamento de memória, eliminam a sobrecarga gerada pela virtualização baseada em tradução binária, elevando os hypervisores bare-metal a um novo patamar, onde aplicações executadas sobre tais virtualizadores obtém, frequentemente, desempenho superior àquelas executadas em plataformas não virtualizadas. Assim, modificações nos modelos de desempenho de aplicações baseadas em SOA atualmente em uso são propostas, de acordo com a análise desenvolvida, para que reflitam os resultados obtidos de forma realista / This PhD thesis analyzes the impact caused by third generation hardware-assisted virtualization on the performance of CPU-bound and memory-intensive SOA-based applications, as well as the impact caused on the marshaling and unmarshalling operations of the SOAP messages executed on the libraries of the application servers. From this analysis is concluded that the resources provided by the hardware platform, mainly considering the memory management, eliminate the overload generated by virtualization based on binary translation, raising the bare-metal hypervisors to a new level, where applications running on these hypervisors reach better performance when compared to those applications running on platforms not virtualized. Thus, modifications on the performance models for SOAbased applications currently in use are proposed accordingly to the analysis developed, aiming at reflecting the results obtained in a realistic fashion
62

Semivolatile compounds from atmospheric monoterpene oxidation / Semivolatile Verbindungen aus der atmosphärischen Monoterpenoxidation

Kahnt, Ariane 09 August 2012 (has links) (PDF)
This PhD thesis aims to improve the knowledge on the processes and chemical species in the gas- and particle-phases that are involved in the production of secondary organic aerosol (SOA) from monoterpene oxidation in the atmosphere. A denuder/filter technique that enabled the simultaneous sampling of gaseous and particulate compounds was applied in the present study. The sampling technique was comprehensively characterised and optimised using twelve atmospherically relevant carbonyl compounds. The present study improved the denuder coating procedure and the sampling performance. An additional coating with the derivatisation reagent, 2,4‑dinitrophenylhydrazine (DNPH), reduced the break-through potential (e.g., from 98% to 0.9% for methyl vinyl ketone) and the fraction of carbonyl compounds on the filter material (e.g., from 8.7% to 0% for acetone). Calibration experiments against an aerosol chamber were performed to reduce the relative standard deviation (RSD) of the calibration points in the denuder measurements. The RSDs were reduced by half for acetone, acetaldehyde, methyl vinyl ketone, glyoxal, benzaldehyde and campholenic aldehyde using a XAD‑4/DNPH denuder, and the quantification error was also reduced. This sampling technique was then applied to a series of α- and β-pinene ozonolysis experiments. The present study examined the influence of an OH radical scavenger (CO), and hence the HO2/RO2 ratio, on the SOA formation, product distribution and partitioning behaviour of selected oxidation products in conjunction with different seed particle acidities. It was shown that SOA yields increased by about 8% in α-pinene ozonolysis when CO and acidic seed particles co-existed, whereas only a marginal difference was observed (increase of 2%) for β-pinene compared to neutral seed particles. From the denuder/filter sample analysis, it was possible to tentatively identify a new compound from the α-pinene ozonolysis, i.e., terpenylic aldehyde. Gas- and particle-phase yields were estimated for the first time for this compound (i.e., 1% and 0.4%, respectively). The atmospheric relevance of terpenylic aldehyde was demonstrated based on ambient filter measurements and a possible formation pathway was suggested. Furthermore, the present study provided an additional explanation for enhanced SOA formation when acidic seed particles are used in monoterpene ozonolysis. It was demonstrated that the isomerisation of monoterpene oxides on acidic seed particles leads to the formation of highly reactive SOA precursors, whose subsequent reaction with ozone contributes significantly to SOA formation.
63

Komplexe Datenanalyseprozesse in serviceorientierten Umgebungen

Habich, Dirk 24 January 2009 (has links) (PDF)
Im Rahmen dieser Dissertation wird sich mit der Einbettung komplexer Datenanalyseprozesse in serviceorientierten Umgebungen beschäftigt. Diese Betrachtung beginnt mit einem konkreten Anwendungsgebiet, indem derartige Analyseprozesse eine entscheidende Rolle bei der Wissenserschließung spielen und ohne deren Hilfe kein Fortschritt erzielt werden kann. Im zweiten Teil werden konkrete komplexe Datenanalyseprozesse entwickelt, die den Ausgangspunkt für die Erörterung der Einbettung in eine serviceorientierte Umgebung bilden. Auf diese Einbettung wird schlussendlich im dritten Teil der Dissertation eingegangen und entsprechende Erweiterungen an den Technologien der bekanntesten Realisierungsform präsentiert. In der Evaluierung wird gezeigt, dass diese neue Form wesentlich besser geeignet ist für komplexe Datenanalyseprozesse als die bisherige Variante.
64

RoSe : un framework pour la conception et l'exécution d'applications distribuées dynamiques et hétérogènes / RoSe : A framework for the design and execution of dynamic and heterogeneous distributed applications.

Bardin, Jonathan 02 October 2012 (has links)
L'adaptation est aujourd'hui devenue un enjeu majeur en Génie Logiciel. Les ingénieurs sont en effet régulièrement confrontés à des demandes d'évolution qui peuvent prendre de nombreuses formes : mises à jour, nouvelles versions, besoins en nouvelles fonctionnalités, etc. Cette tendance est accrue par l'émergence de nouveaux domaines tels que l'informatique ubiquitaire ou le cloud computing qui exigent des changements dynamiques dans des environnements en constante évolution. Ainsi, dans ces domaines, les ressources sont souvent élastiques, volatiles et hétérogènes. Cette thèse s'intéresse en particulier à la conception et à l'exécution d'applications distribuées composées d'entités hétérogènes et qui nécessitent d'être adaptées durant l'exécution. Notre approche s'appuie sur les modèles à composant orientés service et sur les styles d'architectures SOA et REST. Nous proposons un framework, nommé RoSe, qui permet l'import de ressources distantes dans un framework à composant orienté service et l'export de service locaux. RoSe permet aux développeurs et aux administrateurs de gérer la distribution des applications de manière totalement indépendante et dynamique grâce à un langage de configuration et d'une API dite fluent. Le framework lui-même est modulaire et flexible et supporte l'ajout et le retrait de composants durant l'exécution. L'implantation de RoSe est hébergée au sein du projet OW2 Chameleon et est aujourd'hui utilisée dans plusieurs projets industriels et académiques. / Adaptation has now become a major challenge in Software Engineering. Engineers are indeed regularly confronted with requests for changes that can take many forms: updates, new versions, new features need etc. This trend is enhanced by the emergence of new areas such as ubiquitous computing or cloud computing that require dynamic changes in rapidly constantly evolving environments. For instance, in these areas, resources are often elastic, volatile and heterogeneous. %This thesis focuses especially in the design and execution of distributed applications composed of heterogeneous entities which need to be adapted at runtime. Our approach is based on service-oriented component models and on the SOA and REST architectural styles. We propose a framework, named RoSe, which enables the import of remote resources in a service-oriented component framework and the export of local services. RoSe allows developers and administrators to manage the distribution of their application in a totally independent and dynamic way thanks to a configuration language and a fluent API. The framework itself is modular, flexible and supports the addition and removal of components during execution. The implementation of RoSe is hosted by OW2 in the Chameleon project and is now used in several industrial and academic projects.
65

Caracterização de cargas de trabalho para avaliação de desempenho em Web services / Workload Characterization for Performance Evaluation in Web Services

Thiago Caproni Tavares 02 July 2009 (has links)
Esta dissertação de mestrado aborda um estudo sobre a caracterização de cargas de trabalho para Web services por meio da análise de Documentos WSDL (Web Service Description Language). Esses documentos, que representam a interface para os serviços, foram obtidos na Web e seus conteúdos analisados estatisticamente. A metodologia utilizada para alcançar a caracterização desejada, constitui-se da coleta e análise dos dados de 1346 arquivos WSDL válidos. O resultado do estudo proposto nesta dissertação contribui para a avaliação de desempenho no que diz respeito a caracterizar os diversos aspectos das cargas de trabalho de Web services. Dentre os dados obtidos ressaltam-se as porcentagens da ocorrência de algumas características tais como o número de operações, tipos de Binding, quantidade de parâmetros de entrada e saída e tipos de dados mais utilizados. Para auxiliar na busca e avaliação das características das WSDLs uma nova ferramenta denominada WSDLAnalyzer é proposta e implementada / This MSc dissertation approaches a study on workload characterization for web services by means of the analysis of WSDL (Web Service Description Language) documents. These documents, that represent the interface to the services, were all obtained in the web and their contents were statistically analyzed. The methodology used to reach the desired characterization comprises the collection and analysis of 1346 WSDL valid files. The result of the study proposed in this dissertation contributes to the performance evaluation of web services in terms of characterizing the several aspects of the workloads. Among the data obtained, the percentage of occurrences of some features, such as the number of operations, the types of binding, the amount of input and output parameters and the more used data types, are highlighted. To support the search and evaluation of the WSDL features a new tool, named WSDLAnalyzer, is proposed and implemented
66

Etude des politiques de sécurité pour les applications distribuées : le problème des dépendances transitives : modélisation, vérification et mise en oeuvre / Study of security policies for distributed applications : the problem of transitive dependencies

Uttha, Worachet 26 September 2016 (has links)
Le contrôle d’accès est un ingrédient fondamental de la sécurité des systèmes d’information. Depuis les années 70, les travaux dans ce domaine ont apporté des solutions aux problèmes de confidentialités des données personnelles avec applications à différents environnements. Parmi les modèles de contrôle d’accès, nous nous intéressons au modèle basé sur les organisations (OrBAC) et nous en proposons une extension adaptée aux contextes distribués tels que les services web. Cette extension est capable de gérer les demandes d’accès transitifs. Ce cas peut se produire quand un service doit appeler un autre service qui peut avoir besoin d’en invoquer à son tour un ou plusieurs autres pour satisfaire la demande initiale. Nous appelons D-OrBAC (Distributed Organisation Based Access Control), l'extension du modèle OrBAC avec une notion de procuration représentée par un graphe de délégation, qui nous permet de représenter les accords entre les différentes organisations impliquées dans la chaîne d’invocations de services, et de garder la trace des autorisations transitives. Nous proposons aussi une technique d’analyse basée sur Datalog permettant de simuler des scénarios d’exécution et de vérifier l’existence de situations non sécurisées. Nous utilisons ensuite des techniques de réécriture pour assurer que la politique de sécurité spécifiée via le modèle D-OrBAC respecte les propriétés importantes telles que terminaison et consistance. Enfin, nous implémentons pour un cas d’étude, le mécanisme d’évaluation des demandes d’accès selon la norme XACML afin de montrer que notre solution est capable de fournir à la fois la fonctionnalité désirée et la sécurité nécessaire pour le système. / The access control is a fundamental ingredient of computer security. Since the 70s, the research in this area has provided many solutions to the privacy issue of personal data with applications to different environments (operating systems, databases, etc.). Among many access control models, we are interested in the model based on organisations (OrBAC) and we propose an extension adapted to distributed environments such as web services. This extended model is able, in particular, to handle access transitive requests. This situation can occur when a service has to call another service that may need to invoke in turn one or more services to meet the initial demand.We call D-OrBAC (Distributed Organisation Based Access Control), the extension of OrBAC model with a notion of delegation represented by a delegation graph. This graph allows us to represent agreements between the different organisations involved in the chain of service invocations, and to keep track of transitive authorisations. We also propose an analytical technique based on Datalog that allows us to simulate execution of scenarios and to check for the existence of unsafe situations.Thereafter, we use rewriting techniques to ensure that the security policy specified via our D-OrBAC model complies with important properties such as termination and consistency. Finally, we implement for a case study, the mechanism of access request evaluations according to the XACML on the WSO2 Identity Server platform to show that our solution is able to provide both the desired functionality and the security for the system.
67

Hypermediaorienterade verksamhetsprocesser

Robèrt, Björn January 2014 (has links)
Webbens framgång har lett till tendens att stora IT-system byggda enligt en centralistisk arkitektur är på väg att ersättas av samverkande distribuerade system. De processorienterade, verksamhetsstödjande systemen utgör inget undandag. I enlighet med denna tendens så finns det ett behov för processtödjande verksamhetssystem att synkronisera och utbyta resultat med med andra verksamhetssystem. Målet med denna undersökning har varit att utreda hur kommunikationen mellan distribuerade verksamhetsprocesser byggda enligt BPMN 2.0-standarden kan implementeras. Ansatsen har varit att en tjänsteorienterad arkitektur baserad på principerna för REST skulle vara en framkomlig väg för att lösa detta problem. Teoretiska studier av tjänsteorienterad arkitektur, BPMN 2.0 samt REST har lett till en minimal implementation baserad på en ”proof-of-concept”-arkitektur i tjänsteplattformen Motrice från Motrice AB. Det konkreta lösningsförslaget utvärderas enligt Richardsons mognadsmodell, där mognadsnivån för lösningsförslaget avgörs i enlighet med denna modell. Slutsatsen är kommunikation mellan distribuerade verksamhetsprocesser bygger på meddelandeflöden, där dessa meddelandeflöden är helt förenliga med principerna för REST. / The success of the web has led to a tendency by which monolithic systems constructed according to a centralistic architecture,are replaced by distributed cooperating systems. Process and business oriented systems are no exception in this regard. This tendency has led to increased demand for process oriented systems to be able to synchronize and exhange results with other business systems. The purpose of this study has been to investigate how communication between distributed business processes built according to the BPMN 2.0 standard can be implemented. The hypothesis was that a service oriented architecture based on the principles of REST would be a viable approach to solve the problem. The theoretical study of service oriented architectures, BPMN and REST have resulted in a minimal implementation based on a proof-of-concept architecture. The concrete solution is then evaluated using Richardsons maturity model, and the maturity level of the solution is assessed according to this model. The conclusions are that communication between distributed BPMN 2.0 processes are based on message flows, where the concrete implementation of message flows are fully compatible with the principles of REST.
68

Préserver la séparation des préoccupations durant l’intégration de domaines hétérogènes dans les systèmes logiciels / Preserving separation of concerns while integrating heterogeneous domains in software systems

Logre, Ivan 01 September 2017 (has links)
La séparation des préoccupations permet de considérer les sous-systèmes en isolation tout en conservant une vision globale du système. La variabilité des domaines impliqués implique donc (i) un effort de composition des méta-modèles hétérogènes représentant ces domaines, (ii) une gestion de la cohérence inter-domaine des modèles produits en isolation et (iii) une gestion de la multiplicité des cibles atteignables dans l'espace des solutions de chacun des domaines. Pour relever ces défis, nous présentons dans cette thèse une approche couvrant trois contributions appliquées sur le cas de la visualisation de données :- une approche de composition respectant l'isolation des domaines en tirant profit des méthodes d'intégration des Architectures Orientées Services (SOA). Les méta-modèles sont encapsulés dans des services, exposant le comportement pertinent via une interface à destination des experts du domaine ;- un moteur de règles métiers qui assure la gestion des interactions entre domaines et permet de détecter les incohérences inter-domaine et de faire remonter aux experts les informations nécessaires à leur résolution ;- une modélisation de la variabilité des produits par caractérisation qui permet de concrétiser les sous-systèmes vers des artefacts concrets.Pour valider l'approche, nous quantifions (i) le surcoût de l'encapsulation en service des domaines, (ii) l'impact de l'externalisation des interactions entre domaines, (iii) l'effort que les experts et l'intégrateur doivent fournir. Enfin, une expérience utilisateur mesure le gain lors de la concrétisation du système et son impact sur la satisfaction vis à vis des visualisations résultantes. / The growing complexity of software engineering leads to the use of separation of concerns, i.e. enable to consider manageable sub-systems while keeping an overview of the whole system. The domain variability involved in these system design imply : (i) to compose multiple heterogeneous metamodels dedicated to each domain, (ii) to handle cross-domain consistency of the model produced in isolation, (iii) and to tame the multiplicity of concrete artefact available in the solution space of each domain. To adress these challenges, we offer in this thesis an approach encompassing three contributions :- an isolation-compliant composition which benefits from Service Oriented Architecture (SOA) integration. Each domain metamodel is embedded in a service exposing the rele- vant behavior through an interface designed and used by domain experts ; - a business rule engine handling the interaction between domains and detecting cross-domain incon- sistency to provide relevant feedback to resolve it ;- a feature-based characterization of the products variability allowing to concretize each sub-system toward concrete artifacts. The contributions are applied on the sensor data visualization use case.We validate (i) the need for domain isolation preservation on a dashboard design project, then we quantify (ii) the overhead of the service encapsulation, (iii) the impact of the externalization of domain interactions, (iv) the effort required from the experts and the integrator. Finally, we proceed to a user experiment to measure the gain during the concretization of a sub-system, and the impact on the user satisfaction on the resulting visualisation widgets.
69

Vliv SOA na podnikové informační systémy společnosti SAP / Influence of SOA on SAP Enterprise Information Systems

Michalička, Jan January 2007 (has links)
This work deals with Service-Oriented Architecture (SOA) and its impact on SAP products. In the first part of the work we are outlining the development of information systems architectures, after that describing SOA architecture, its basic concept, benefits and risks, ways of implementing and other connections. In the next part we are introducing the SAP company and its big historic moments from the beginning till present. We are analyzing the impact of SOA on SAP product and introducing new solutions -- architectural concept Enterprise SOA and application and integration, service-oriented platform SAP NetWeaver. We are discussing its development and its future. In the last part we are demonstrating practically these new solutions.
70

Implementação de mecanismos tolerantes a falhas em uma arquitetura SOA com Qos / Implementation of fault tolerant mechanisms in a SOA architecture with QoS

Edvard Martins de Oliveira 28 August 2013 (has links)
Esta dissertação de mestrado tem como objetivo avaliar a integração de políticas de tolerância a falhas em uma arquitetura de Web Services com múltiplos módulos. A arquitetura utilizada é denominada WSARCH, e foi desenvolvida para o estudo das relações e interoperabilidade entre serviçcos. Os mecanismos de tolerência a falhas foram integrados aos módulos da arquitetura, testados, comparados e avaliados. A avaliação de desempenho mostrou que os mecanismos de tolerância a falhas introduzidos foram eficientes e apresentaram resultados adequados. As técnicas de reputação utilizadas na seleção de serviço atuaram satisfatoriamente e foram consideradas um importante avanço nos mecanismos da arquitetura / This master\'s thesis aims to evaluate the integration of fault tolerance mechanisms in a Web Services architecture with multiple modules. The architecture used is named WSARCH and was developed for the study of interactions and interoperability of services. WSARCH is an architecture conceived to receive tests and experiments involving concepts of Web Services. The fault tolerance tools were integrated in the architecture, tested, evaluated and comparated. The performance evaluation showed that the fault tolerance mechanisms introduced were ecient and presented appropriate results. The reputation techniques utilized in service selection operated successfully and were considered an important advance in the mechanisms of the architecture

Page generated in 0.0172 seconds