• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 277
  • 189
  • 50
  • 48
  • 29
  • 24
  • 19
  • 16
  • 13
  • 11
  • 10
  • 5
  • 5
  • 4
  • 3
  • Tagged with
  • 779
  • 197
  • 131
  • 118
  • 107
  • 93
  • 91
  • 88
  • 82
  • 81
  • 79
  • 77
  • 76
  • 70
  • 63
  • 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.
321

The Use of Process and Simulation Modeling to Inform the Design of Electronic Prescribing Systems

Ghany, Ahmad 04 1900 (has links)
<p>Objectives: (1) to assess whether computer simulation modeling or process modeling have improved medication management systems, including informing the design of e-prescribing systems for Canada, and (2) to build and validate a workflow diagram of the handwritten medication management process in the community setting for Canada and use it to obtain feedback from stakeholders.</p> <p>Methods: A systematic review was conducted to assess whether the modeling techniques have improved medication management systems. A workflow diagram was developed and used to obtain feedback from stakeholders as to where problems exist in the current paper-based process and where information technology might be of help. Analyses were descriptive and qualitative.</p> <p>Results: The systematic review identified 13,376 citations, 8 of which were included in the full data extraction. The review revealed that simulation models of e-prescribing systems have been developed, but their accuracy and usefulness has not been established. One process model had been used to analyze a Canadian medication management system, but no evidence was found that process models had any positive impact on e-prescribing development in Canada.</p> <p>Fifteen stakeholders, including 5 physicians, 5 pharmacists, and 5 members of the public provided feedback using the workflow diagram. All stakeholders agreed that the diagram was a realistic representation of the actual handwritten medication management process, suggesting face validity. The majority of stakeholders identified the most problematic processes as generating the prescription by the physician (9/15 (60.0%)) and drug checking by the physician (6/15 (40.0%)).</p> <p>Conclusions: There is a lack of published evidence on simulation models and process models, and the studies that exist do not suggest any benefit in informing e-prescribing design. We developed and established face validity for a workflow diagram of the paper-based medication management cascade. Stakeholders believed that generating the prescription and drug checking by the physician could be improved by e-prescribing.</p> / Master of Science (MSc)
322

組織實施工作流管理之研究—以個案組織為例

賴淑蓉, Lai , ShuRong Unknown Date (has links)
隨著資訊科技不斷進行,資訊電腦、資訊與網路通訊科技的整合應用,除了改變現今生活的全貌,而同時深入改變企業或政府組織的角色,以及其經營之道的理念與做法,此外嶄新的管理與決策工具,也輔助高階主管的管理作業。而一個成功的企業或政府組織為能彈性因應外在競爭及劇變環境,需使其內部之資訊互通整合,以達組織間之企業流程、工作流運作順暢,而發揮企業之最大效率。藉由新科技的輔助,企業除內部工作流流線化外,對外也可增加其回應能力,以及提高其競爭能力。 本研究採個案研究方式,依據所提出之建立工作流模型及工作流管理系統之方法,選定一個案組織進行驗證。以整合性跨部門之業務流程出發,建立組織之業務流程模型,經流程分析及問題探討後,提出一套建議未來合理之業務流程模型,依未來合理之業務流程建立工作流模型,並進一定定義及強化資訊系統自動追蹤及稽催之角色,設計工作流管理系統。於所有活動均被正式定義以及追蹤管理之下,對於各項活動執行之作業成本及其績效,均能明確記載,因此可提供每年或外在環境改變時,進行對業務流程之檢討,再啟動本研究提出之方法,而每一次之檢討,可助於組織重新設計執行績效更佳之業務流程及工作流。
323

Formalização de workflow nets utilizando lógica linear: análise qualitativa e quantitativa

Passos, Lígia Maria Soares 27 May 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents a method for qualitative and quantitative analysis of WorkFlow nets based on the proof trees of linear logic, and an approach for the verification of workflow specifications in UML through the transformation of UML Activity Diagrams into WorkFlow nets. The qualitative analysis is concerned with the proof of soundness correctness criterion defined for WorkFlow nets. The quantitative analysis is based on the computation of symbolic dates for the planning of resources used to handle each task of the workflow process modeled by a t-Time WorkFlow net. For the verification of the specifications of workflow processes mapped into UML Activity Diagrams are presented formal rules to transform this ones into WorkFlow nets. In this context is proposed the analysis and correction of critical points in UML Activity Diagrams through the analysis of proof trees of linear logic. The advantages of such an approach are diverse. The fact of working with linear logic permits one to prove the correctness criterion soundness in a linear time without considering the construction of the reachability graph, considering the proper structure of the WorkFlow net instead of considering the corresponding automata. Moreover, the computation of symbolic dates for the execution of each task mapped into the t-Time WorkFlow net permits to plan the utilization of the resources involved in the activities of the workflow process, through formulas that can be used for any case handled by the correspondent workflow process, without to examine again the process to recalculate, for each new case, the dates of start and conclusion for the activities involved in the process. Regarding the verification of workflow processes mapped into UML Activity Diagrams, the major advantage of this approach is the transformation of a semi-formal model into a formal model, such that some properties, like soundness, can be formally verified. / Este trabalho apresenta um método para a análise qualitativa e quantitativa de Work- Flow nets baseado nas árvores de prova canônica da lógica linear e uma abordagem para a verificação de especificações de processos de workflow em UML através da transformação de Diagramas de Atividades da UML em WorkFlow nets. A análise qualitativa refere-se à prova do critério de corretude soundness definido para WorkFlow nets. Já a análise quantitativa preocupa-se com o planejamento de recursos para cada atividade de um processo de workflow mapeado em uma t-Time WorkFlow net e baseia-se no cálculo de datas simbólicas para o planejamento de recursos utilizados na realização de cada tarefa do processo de workflow. Para a verificação das especificações de processos de workflow mapeados em Diagramas de Atividades da UML são apresentadas regras formais para transformar estes diagramas em WorkFlow nets. Neste contexto também é proposta a análise e correção de pontos críticos em Diagramas de Atividades da UML através da análise de árvores de prova canônica da lógica linear. As vantagens das abordagens apresentadas neste trabalho são diversas. O fato de trabalhar com lógica linear permite provar o critério de corretude soundness em tempo linear e sem que seja necessária a construção de um grafo das marcações acessíveis, considerando diretamente a própria estrutura da WorkFlow net, ao invés de considerar o seu autômato correspondente. Além disso, o cálculo de datas simbólicas correspondentes à execução de cada tarefa mapeada em uma t-Time WorkFlow net permite planejar a utilização dos recursos envolvidos nas atividades do processo de workflow, através de fórmulas que podem ser utilizadas por qualquer caso tratado pelo processo de workflow correspondente, sem que seja necessário percorrer novamente o processo de workflow inteiro para recalcular, para cada novo caso, datas de início e término das atividades envolvidas no processo. Já no que diz respeito à verificação de processos de workflow mapeados em Diagramas de Atividades da UML, a principal vantagem desta abordagem é a transformação de um modelo semi-formal em um modelo formal, para o qual algumas propriedades, como soundness, podem ser formalmente verificadas. / Mestre em Ciência da Computação
324

Uma metodologia baseada na lógica linear para análise de processos de workflow interorganizacionais

Passos, Lígia Maria Soares 22 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work formalizes four methods based on Linear Logic for the verification of interorganizational workflow processes modelled by Interorganizational Workflow nets, which are Petri nets that model such processes. The first method is related to the verification of the Soundness criteria for interorganizational workflow processes. The method is based on the construction and analysis of Linear Logic proof trees, which represent the local processes as much as they do the global processes. The second and third methods are related, respectively to Soundness criteria verification, Relaxed Soundness and Weak Soundness for the interorganizational workflow processes. These are obtained through the analysis of reutilized Linear Logic proof trees that have been constructed for the verification of the Soundness criteria. However, the fourth method has the objective of detecting the deadlock free scenarios in interorganizational workflow and is based on the construction and analysis of Linear Logic proof trees, which initially takes into consideration the local processes and communication between such, and thereafter the candidate scenarios. A case study is carried out in the context of a Web services composition check, since there is a close correlation between the modelling of the interorganizational workflow process and a Web services composition. Therefore, the four methods proposed in the interorganizational workflow process context, are applied to a Web services composition. The evaluation of the obtained results shows that the reutilization of Linear Logic proof trees initially constructed for verifying the Soundness criteria, in fact occurs in the context of verifying the Relaxed Soundness andWeak Soundness criteria. In addition, the evaluation shows how the Linear Logic sequents and their proof trees explicitly show the possibilities for existing collaborations in a Web service composition. An evaluation that takes into account the number of constructed linear logic proof trees shows that this number can be significantly reduced in the deadlock-freeness scenarios detection method. An approach for resource planning based on the symbolic date calculation, which considers data extracted from Linear Logic proof trees is presented and validated through simulations performed on the CPN tools simulator. Two approaches for the monitoring of deadlockfreeness scenarios are introduced and show how data obtained from the Linear Logic proof trees can be used to guide the execution of such scenarios. / Este trabalho formaliza quatro métodos baseados na Lógica Linear para verificação de processos de workflow interorganizacionais modelados por WorkFlow nets interorganizacionais, que são redes de Petri que modelam tais processos. O primeiro método está relacionado com a verificação do critério de correção Soundness para processos de workflow interorganizacionais. O método é baseado na construção e análise de árvores de prova da Lógica Linear que representam tanto os processos locais quanto o processo global. O segundo e terceiro métodos estão relacionados, respectivamente, com a verificação dos critérios de correção Relaxed Soundness e Weak Soundness para processos de workflow interorganizacionais, e são obtidos através da análise de árvores de prova da Lógica Linear reutilizadas, construídas para a prova do critério de correção Soundness. Já o quarto método tem por objetivo a detecção dos cenários livres de deadlock em processos de workflow interorganizacionais e é baseado na construção e análise de árvores de prova da Lógica Linear que consideram, inicialmente, os processos locais e as comunicações entre estes e, posteriormente, os cenários candidatos. Um estudo de caso é realizado no contexto da verificação de composições de serviços Web, uma vez que há uma relação estreita entre a modelagem de um processo de workflow interorganizacional e uma composição de serviços Web. Assim, os quatro métodos propostos no contexto dos processos de workflow interorganizacionais são aplicados a uma composição de serviços Web. A avaliação dos resultados mostra que o reuso de árvores de prova da Lógica Linear construídas inicialmente para a prova do critério de correção Soundness de fato ocorre no contexto da verificação dos critérios de correção Relaxed Soundness e Weak Soundness. Além disso, a avaliação mostra como os sequentes da Lógica Linear e suas árvores de prova explicitam as possibilidades de colaboração existentes em uma composição de serviços Web. Uma avaliação que leva em conta o número de árvores de prova da Lógica Linear construídas mostra que este número pode ser significativamente reduzido no método para detecção de cenários livres de deadlock. Uma abordagem para planejamento de recursos, baseada no cálculo de datas simbólicas, que considera dados extraídos de árvores de prova da Lógica Linear, é apresentada e validada através de simulações realizadas no simulador CPN Tools. Duas abordagens para a monitoração dos cenários livres de deadlock são introduzidas e mostram como dados obtidos nas árvores de prova da Lógica Linear podem ser utilizados para guiar a execução de tais cenários. / Doutor em Ciência da Computação
325

Context driven workflow adaptation applied to healthcare planning = Adaptação de workflows dirigida por contexto aplicada ao planejamento de saúde / Adaptação de workflows dirigida por contexto aplicada ao planejamento de saúde

Vilar, Bruno Siqueira Campos Mendonça, 1982- 25 August 2018 (has links)
Orientadores: Claudia Maria Bauzer Medeiros, André Santanchè / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-25T03:19:51Z (GMT). No. of bitstreams: 1 Vilar_BrunoSiqueiraCamposMendonca_D.pdf: 3275725 bytes, checksum: 4ccdd82eebca5b8da9748c7c515ea4c1 (MD5) Previous issue date: 2014 / Resumo: Sistemas de Gerenciamento de Workflows (WfMS -- em inglês) são usados para gerenciar a execução de processos, melhorando eficiência e eficácia de procedimentos em uso. As forças motrizes por trás da adoção e do desenvolvimento de um WfMS são aplicações científicas e de negócios. Esforços conjuntos de ambos resultaram em mecanismos consolidados, além de padrões e protocolos consensuais. Em particular, um WfMS científico (SWfMS -- \textit{Scientific WfMS}) auxilia cientistas a especificar e executar experimentos distribuídos. Ele fornece diferentes recursos que suportam atividades em um ambiente experimental, como prover flexibilidade para mudar o projeto de workflow, manter a proveniência e suportar reproducibilidade de experimentos. Por outro lado, apesar de poucas iniciativas de pesquisa, WfMSs não fornecem suporte apropriado à personalização dinâmica e baseada em contexto durante a execução; adaptações em tempo de execução normalmente requerem intervenção do usuário. Esta tese se concentra em superar essa deficiência, fornecendo a WfMSs um mecanismo de ciente do contexto para personalizar a execução de workflows. Como resultado, foi projetado e desenvolvido o DynFlow -- uma arquitetura de software que permite tal personalização aplicada a um domínio: planejamento de saúde. Este domínio foi escolhido por ser um ótimo exemplo de personalização sensível ao contexto. Procedimentos de saúde constantemente sofrem mudanças que podem ocorrer durante um tratamento, como a reação de um paciente a um medicamento. Para suprir a demanda, a pesquisa em planejamento de saúde desenvolveu técnicas semi-automáticas para suportar mudanças rápidas dos passos de fluxos de tratamento, de acordo com o estado e a evolução do paciente. Uma dessas técnicas é \textit{Computer-Interpretable Guidelines} (CIG), cujo membro mais proeminente é \textit{Task-Network Model} (TNM) -- uma abordagem baseada em regras capaz de construir um plano em tempo de execução. Nossa pesquisa nos levou a concluir que CIGs não suportam características necessárias por profissionais de saúde, como proveniência e extensibilidade, disponíveis em WfMSs. Em outras palavras, CIGs e WfMSs têm características complementares e são direcionadas à execução de atividades. Considerando os fatos citados, as principais contribuições desta tese são: (a) especificação e desenvolvimento do DynFlow, cujo modelo associa características de TNMs e WfMS; (b) caracterização das principais vantagens e desvantagens de modelos CIGs e WfMSs; (c) implementação de um protótipo, baseado em ontologias e aplicadas ao domínio da saúde e enfermagem / Abstract: Workflow Management Systems (WfMS) are used to manage the execution of processes, improving efficiency and efficacy of the procedure in use. The driving forces behind the adoption and development of WfMSs are business and scientific applications. Associated research efforts resulted in consolidated mechanisms, consensual protocols and standards. In particular, a scientific WfMS helps scientists to specify and run distributed experiments. It provides several features that support activities within an experimental environment, such as providing flexibility to change workflow design and keeping provenance (and thus reproducibility) of experiments. On the other hand, barring a few research initiatives, WfMSs do not provide appropriate support to dynamic, context-based customization during run-time; on-the-fly adaptations usually require user intervention. This thesis is concerned with mending this gap, providing WfMSs with a context-aware mechanism to dynamically customize workflow execution. As a result, we designed and developed DynFlow ¿ a software architecture that allows such a customization, applied to a specific domain: healthcare planning. This application domain was chosen because it is a very good example of context-sensitive customization. Indeed, healthcare procedures constantly undergo unexpected changes that may occur during a treatment, such as a patient¿s reaction to a medicine. To meet dynamic customization demands, healthcare planning research has developed semi-automated techniques to support fast changes of the careflow steps according to a patient¿s state and evolution. One such technique is Computer-Interpretable Guidelines (CIG), whose most prominent member is the Task-Network Model (TNM) -- a rule based approach able to build on the fly a plan according to the context. Our research led us to conclude that CIGs do not support features required by health professionals, such as distributed execution, provenance and extensibility, which are available from WfMSs. In other words, CIGs and WfMSs have complementary characteristics, and both are directed towards execution of activities. Given the above facts, the main contributions of the thesis are the following: (a) the design and development of DynFlow, whose underlying model blends TNM characteristics with WfMS; (b) the characterization of the main advantages and disadvantages of CIG models and workflow models; and (c) the implementation of a prototype, based on ontologies, applied to nursing care. Ontologies are used as a solution to enable interoperability across distinct SWfMS internal representations, as well as to support distinct healthcare vocabularies and procedures / Doutorado / Ciência da Computação / Doutor em Ciência da Computação
326

Business process management in an intrapreneurial software organisation / Ulrike Janke

Janke, Ulrike January 2006 (has links)
Business process management (BPM) is a philosophical approach to organisation-wide management in which the focus is on the processes through which it operates, and in particular the streamlining and optimising of these processes, for which software solutions may be used. CTexT is an intrapreneurial software organisation that has been experiencing problems with software development due to a lack of formal processes relating to customer support, versioning, configuration, quality, risk and project management. The objective of the study is to determine whether the implementation of an electronic BPM system can effectively solve CTexT's development problems and thereby improve its overall software development capacity. More specifically, the focus is on i) the effect of the resulting standardisation on creativity and innovation, and ii) implementation matters, such as the type of processes that can be subjected to an electronic system, and how CTexT can overcome the time and cost constraints of such a system. The study investigates these questions by means of a literature investigation in combination with interviews with knowledgeable respondents from other innovative and software organisations. Interviews with six employees from CTexT determine the relevance of these findings and highlight critical areas for process improvement. Since BPM systems improve organisational efficiencies and are generally employed in larger corporate contexts marked by transactional and repetitive activities where they enforce administrative rules, the conclusion is drawn that a BPM system will not be suitable for an intrapreneurial organisation, and that it is likely to cause more disruption to the creative environment than improve its operations. It is further shown that although a BPM system is theoretically applicable to software development, it generally does not seem to be applied practically in the industry, and the suitability of this process as manageable through a BPM system is seriously questioned. Instead, the research points to improvement through the application of software development methodologies and a holistic approach towards BPM. The investigation at CTexT confirms that its development problems relate to flawed methodologies and that remedies should therefore focus on improving its methodologies and controlling certain aspects of the software development life cycle by means of suitable software tools. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2007
327

Epidémiologie moléculaire et métagénomique à haut débit sur la grille / Molecular epidemiology and high-throughput metagenomics on the grid

Doan, Trung-Tung 17 December 2012 (has links)
Résumé indisponible / The objective of this thesis focuses on the study and the development of bioinformatics platforms and tools on the grid. The second objective is to develop applications in molecular epidemiology and metagenomics based on these tools and platforms. Based on the studies of existing bioinformatics platforms and tools, we propose our solution: a platform and a portal for molecular epidemiology and high throughput metagenomics on the grid. The main idea of ​​our platform is to simplify the submission of jobs to the grid via the pilots jobs (jobs generic that can control and launch many real tasks) and the PULL model (tasks are retrieved and executed automatically). There are other platforms that have similar approaches but our platform focuses on the simplicity and the saving time for the submission of jobs. Bioinformatics tools chosen to deploy the platform are popular tools that can be used in many bioinformatics analyses. We apply a workflow engine in the platform so that users can make the analysis easier. Our platform can be seen as a generalized system that can be applied to both the epidemiological surveillance and metagenomics of which two use cases are deployed and tested on the grid. The first use case is used to monitor bird flu. The approach of this application is to federate data sequences of influenza viruses and provide a portal with tools on the grid to analyze these data. The second use case is used to apply the power of the grid in the analysis of high throughput sequencing of amplicon sequences. In this case, we prove the efficiency of the grid by using our platform to gridifier an existing application, which has much less performance than the gridified version.
328

Optimalizace projektových portfolií s časem a zdroji / Project portfolio optimisation with time and resources

Huml, Tomáš January 2012 (has links)
Title: Project portfolio optimization with time and resources Author: Bc. Tomáš Huml Department: Department of Theoretical Computer Science and Mathematical Logic Supervisor: Doc. RNDr. Roman Barták, Ph.D Abstract: Traditional project portfolio optimization deals with static projects that are not evolving in time. The focus of this diploma thesis is on projects that are spread in time, typically such projects consists of a sequence (or other partially ordered structure) of actions that require some resources (money, people, etc.) for realization. Then the project portfolio optimization deals with selecting a subset of projects according to given time and space (resource) restrictions and optimizing certain criteria such as overall profit. This problem is very close to oversubscribed scheduling where the most profitable subset of orders is being scheduled. Hence scheduling techniques will be the main inspiration for solving this new type of problems. Lots of modelling algorithms for optimal portfolio selection are proposed in this diploma thesis and several of them are implemented in a program which is part of this thesis as well. Keywords: portfolio optimization, integer linear programming (ILP), workflow optimization, project interdependencies
329

Outils et modèles collaboratifs pour la gestion des tensions dans les services des urgences pédiatriques / Collaborative tools and models for the management of tensions in the services emergency pediatric

Ajmi, Inès 16 June 2015 (has links)
Dans la gestion des systèmes de production de soins, la maîtrise des flux hospitaliers et l'anticipation des tensions sont des enjeux majeurs. Les acteurs du secteur hospitalier et des filières de soins doivent maîtriser des tensions telles les pics d'activités et les engorgements de services qui sont liées aux flux des patients et aux flux des processus de soins. Ils sont toutefois démunis en méthodologies et outils d'aide à la décision et de pilotage adaptés. Cette thèse a pour but d’étudier et de développer la modélisation, l'optimisation et la mise en œuvre d'un Système d’Aide à l’amélioration de la prise en charge des patients en mode normal et en mode tension dans les Services des Urgences Pédiatriques (SUP) du CHRU de Lille. L’objectif de cette thèse est de proposer des solutions appropriées au SUP permettant d’améliorer la prise en charge des patients en termes de temps d’attente. Nous avons donc modélisé le processus de prise en charge des patients par l’approche Workflow afin d’identifier les dysfonctionnements au SUP près cette phase de modélisation, nous avons proposé une architecture de résolution à base d’agents afin d’optimiser l’ordonnancement des flux patients et diminuer considérablement leur temps d’attente en périodes des tensions. Ensuite nous avons étudié une démarche d’orchestration dynamique du Workflow par les agents afin de réduire les temps d’attentes des patients en cours d’exécution. Cette these est menée dans le cadre du projet ANR HOST avec la collaboration du SUP de CHRU de Lille. Les résultats des simulations mettent en exergue l’apport de l’alliance entre les systèmes multi-agent et l’optimisation pour l’aide à la décision. / In the healthcare production management systems, the control of the patient flows and the anticipation of the tensions are major issues. Due to the increasing the crowding situations and their consequences, there is an ever increasing emphasis on the ability of the actors in hospital and healthcare pathways to manage the patient health care process. They must be able to control the crowding (peaks of activities, congestion of services) that are related to patient and healthcare processes flows. However, decision makers do not have sufficient methodologies and decision support tools adapted for controlling the patient flows.This thesis aims to investigate and develop modeling, optimization and implementation of a Support System to improve the care of patients in normal situation and crowding situation in Services Pediatric Emergencies (SUP) of the Lille University Hospital. The objective of this thesis is to propose appropriate solutions to the SUP to improve care for patients in terms of wait times. We therefore modeled the process of care for patients by Workflow approach to identify malfunctions in the SUP near the modeling phase; we proposed a resolution of agent-based architecture to optimize scheduling patient flow and significantly decrease their waiting time during periods of tension. Then we studied a dynamic process orchestration workflow by agents to reduce the expectations of patients running time. This thesis is conducted under the ANR HOST project in collaboration with the Lille University Hospital SUP. The simulation results highlight the contribution of the alliance between the multi-agent systems and optimization for decision support
330

Résilience dans les Systèmes de Workflow Distribués pour les Applications d’Optimisation Numérique : Conception et Expériences / Collaborative platform for multidiscipline optimization

Trifan, Laurentiu 21 October 2013 (has links)
Cette thèse vise à la conception d'un environnement pour le calcul haute performance dans un cadre d'optimisation numérique. Les outils de conception et d’optimisation sont répartis dans plusieurs équipes distantes, académiques et industrielles, qui collaborent au sein des mêmes projets. Les outils doivent être fédérés au sein d’un environnement commun afin d'en faciliter l'accès aux chercheurs et ingénieurs. L'environnement que nous proposons, pour répondre aux conditions précédentes, se compose d’un système de workflow et d’un système de calcul distribué. Le premier a pour objectif de faciliter la tâche de conception de l'application tandis que le second se charge de l’exécution sur des ressources de calcul distribuées. Bien sûr, des services de communication entre les deux systèmes doivent être développés. Les calculs doivent être réalisés de manière efficace, en prenant en compte le parallélisme interne de certains codes, l’exécution synchrone ou asynchrone des tâches, le transfert des données et les ressources matérielles et logicielles disponibles (répartition de charge par exemple). De plus, l’environnement doit assurer un bon niveau de tolérance aux pannes et aux défaillances logicielles, afin de minimiser leur influence sur le résultat final ou sur le temps de calcul. Une condition importante en particulier est de pouvoir implanter des dispositifs de reprise sur erreur, de telle sorte que le temps supplémentaire de traitement des erreurs reste très inférieur au temps de re-exécution total. Dans le cadre de ce travail, notre choix s'est porté sur le moteur de workflow Yawl, qui présente de bonnes caractéristiques en termes i) d'indépendance vis à vis du matériel et du logiciel (système client-serveur pouvant fonctionner sur du matériel hétérogène) et ii) de mécanisme de reprise sur erreur. Pour la partie calcul distribué, nos expériences ont été réalisées sur la plateforme Grid5000, en utilisant jusqu'à 64 machines différentes réparties sur cinq sites géographiques. Ce document détaille les choix de conception de cet environnement ainsi que les ajouts et modifications que nous avons été amenés à apporter à Yawl pour lui permettre de fonctionner sur une plateforme distribuée. / This thesis aims conceiving an environment for high performance computing in a numerical optimization context. The tools for conception and optimization are distributed across several teams, both academics and industrial, which collaborate inside a unique project. The tools should be federated within a common environment to facilitate access to researchers and engineers. The environment that we offer, in order to meet the above conditions, consists of a workflow system and a distributed computing system. The first system aims to facilitate the application design task while the latter is responsible for executing on distributed computing resources. Of course, communication services between the two systems must be developed. The computation must be performed effectively, taking into account the internal parallelism of some software code, synchronous or asynchronous task execution, the transfer of data and hardware and software resources available (e.g. load balancing). In addition, the environment should provide a good level of fault tolerance and software failures, to minimize their influence on the final result or the computation time. An important condition in particular is to implement recovery devices on error occurence, so that the extra time for error handling remains well below the total time of re-execution. As part of this work, our choice fell on the Yawl workflow engine, which has good characteristics in terms of i) hardware and software independence (client-server system that can run on heterogeneous hardware) and ii) error recovery mechanism. For distributed computing part, our experiments were performed on the Grid5000 platform, using up to 64 different machines on five geographical sites. This document details the design of this environment and the extensions and changes we have had to perform on Yawl to enable it to run on a distributed platform.

Page generated in 0.0499 seconds