Darbe siekiama sudaryti metodiką, kuri leistų kurti informacines sistemas grindžiamas darbų sekų vykdymų. Norint pasiekti tikslą reikia išanalizuoti esamas kūrimo metodikas ir išsirinkti geriausias savybes, kurias panaudosiu naujos metodikos sudaryme. / In this paper work I am aiming to design a methodology that enables to develop information systems based on workflow execution. In order to achieve the objective I should to analyze the existing development methodologies and choose the best features, which I combine to create a new methodology.

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 memes projets. Les outils doivent etre fédérésau 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 objctif de faciliter la tache de conception tandis que le second se charge de l'exécution sur des ressources de calcul distribuées. Bien sur, des suystèmes de communication entre les deux systèmes doivent etre développés. Les calculs doivent etre réalisés de manière efficace, en prenant en compte le parallélisme interne de certains codes, l'exécution synchrone ou asynchrone des taches, le transfert des données et les ressources matérielles et logicielles disponibles. 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 est de pouvoir implanter un dispositif de reprise sur erreur, de telle sorte que le temps supplémentaire de traitement des erreurs soit très inférieur au temps de ré-exécution total.Dans le cadre de ce travail, notyre choix s'est porté sur le moteur de workflow Yawl, qui présente de bonnes caractéristiques en termes i) d'indépendancze vis à vis du matériel et du logiciel et ii) de mécanisme de reprise sdur erreur. Pour la partie calcul distribué, nos expériences ont été réalisées sur la plateforme Grid5000, en utilisant 64 machines différentes réparties sur cinq sites géographiques. Ce document d&taille les choix de conception de cet environnement ainsi que les ajouts et modifications que nous avons apportées à Yawl pour lui permettre de fonctionner sur une plateforme distribuée.

La technologie de workflow, tendant à automatiser les processus d'entreprise et à fournir un support pour leur gestion, est aujourd'hui un secteur actif de recherche. C'est dans ce contexte que se situent ces travaux de thèse qui portent aussi bien sur la modélisation des processus workflow que sur leur vérification. Ces processus, pouvant être contraints par des ressources partagées ou encore par des durées de traitement, doivent être vérifiés avant d'être confiés aux systèmes de gestion de workflow qui vont les exécuter. Nous nous sommes intéressés par la vérification de la propriété de cohérence (soundness) des réseaux de workflow (WF-net) : sous-classes des réseaux de Petri (RdPs) modélisant les processus workflow.Dans ce cadre, en explorant la théorie structurelle des RdPs, nous avons identifié des sous-classes de WF-nets pour lesquelles la cohérence peut être vérifiée et caractérisée efficacement. Nous nous sommes focalisés en outre sur l'extension de ces sous-classes en tenant compte de la présence de ressources partagées et sur la propriété de cohérence en présence d'un nombre arbitraire d'instances prêtes à s'exécuter. Dans cette partie, nous avons dû automatiser le calcul des siphons minimaux dans un RdP. Pour ce faire, nous avons choisi un algorithme de la littérature et l'amélioré par la recherche et la contraction de circuits alternés.Ensuite, nous avons abordé la modélisation et la vérification de processus workflow tenant compte des contraintes temporelles. Nous avons en premier lieu proposé un modèle de TWF-net (WF-net Temporisé). Pour ce modèle, nous avons défini la propriété de cohérence temporelle et proposé une condition nécessaire et suffisante pour la vérifier. En deuxième lieu, nous avons relaxé les contraintes temporelles adoptées par la proposition d'un modèle temporel visant des processus à contraintes temporelles variant dans des intervalles de temps. Nous avons défini formellement le modèle de ITWF-net (Interval Timed WF-net) et donné sa sémantique. Par ailleurs, nous avons développé et testé un prototype de modélisation et de simulation des ITWF-nets.La dernière partie de cette thèse a concerné la vérification formelle des processus workflow par SPIN model checker. Nous avons dû en premier lieu traduire la spécification des workflows adoptée vers Promela : le langage de description des modèles à vérifier par SPIN. En second lieu, nous avons exprimé les propriétés de cohérence en Logique Linéaire Temporelle (LTL) et utilisé SPIN pour tester si chaque propriété est satisfaite par le modèle Promela du WF-net en question. Enfin, nous avons exprimé les propriétés de k-cohérence pour les WF-nets modélisant plusieurs instances et de (k,R)-cohérence pour les processus workflow concurrents et qui possèdent des ressources partagées.

The increasing amounts of electronic data of all forms, produced by humans (e.g. Web pages, structured content such as Wikipedia or the blogosphere etc.) and/or automatic tools (loggers, sensors, Web services, scientific programs or analysis tools etc.) leads to a situation of unprecedented potential for extracting new knowledge, finding new correlations, or simply making sense of the data.Visual analytics aims at combining interactive data visualization with data analysis tasks. Given the explosion in volume and complexity of scientific data, e.g., associated to biological or physical processes or social networks, visual analytics is called to play an important role in scientific data management.Most visual analytics platforms, however, are memory-based, and are therefore limited in the volume of data handled. Moreover, the integration of each new algorithm (e.g. for clustering) requires integrating it by hand into the platform. Finally, they lack the capability to define and deploy well-structured processes where users with different roles interact in a coordinated way sharing the same data and possibly the same visualizations.This work is at the convergence of three research areas: information visualization, database query processing and optimization, and workflow modeling. It provides two main contributions: (i) We propose a generic architecture for deploying a visual analytics platform on top of a database management system (DBMS) (ii) We show how to propagate data changes to the DBMS and visualizations, through the workflow process. Our approach has been implemented in a prototype called EdiFlow, and validated through several applications. It clearly demonstrates that visual analytics applications can benefit from robust storage and automatic process deployment provided by the DBMS while obtaining good performance and thus it provides scalability.Conversely, it could also be integrated into a data-intensive scientific workflow platform in order to increase its visualization features.

A flexible, scalable, and asynchronous middleware abstract is needed for business process management, which involves thousands of tasks and a large number of running instances of large business processes. The content-based publish/subscribe system is an ideal candidate to serve as enterprise service bus for these applications. In the publish/subscribe paradigm, information providers called publishers disseminate publications to all subscribers who have expressed interests by registering subscriptions through a loosely coupled interface. However, the traditional publish/subscribe paradigm only supports stateless subscriptions, that is, event correlation is ignored. Moreover, subscribers can only receive publications issued after their subscriptions. There are many application contexts, however, where access to publications from the past is necessary,such as for replaying a business process execution to debug it. Even more interesting uses arise when data from the past can be correlated with those in the future. Therefore, new languages and new functionalities are needed in the standard publish/subscribe model in order to support business process management. A new subscription language PADRES SQL(PSQL) which can express event patterns and unify both historic and future views for subscribers. PADRES allows a subscriber to access data published both in the past and in the future. Furthermore, complex event detection happens in the broker network. The main difficulties of distributed event detection are routing a composite subscription, including where and how to decompose the composite subscription, and routing the individual parts of the subscription. Our composite subscription routing decisions are based on a cost model which minimizes the routing and detection delay. An adaptive subscription routing protocol is proposed to determine efficient location with dynamic changing workloads. PADRES also provides robust message delivery by exploring alternative paths in a cyclic overlay. Routing optimizations and efficient matching algorithms are studied to improve the performance of the extended publish/subscribe model. With the above features, we propose the Ninos system, the distributed business process execution architecture as a case study,which uses light-weight activity agents to carry out business process execution in a distributed environment. Ninos proves that decentralized business process execution is the trend for next generation products, and the publish/subscribe model is ideal to serve as an enterpriser service bus (ESB) for distributed applications.

In the current information age, large amounts of data are being generated and accumulated rapidly in various industrial and scientific domains. This imposes important demands on data processing capabilities that can extract sensible and valuable information from the large amount of data in a timely manner. Hadoop, the open source implementation of Google's data processing framework (MapReduce, Google File System and BigTable), is becoming increasingly popular and being used to solve data processing problems in various application scenarios. However, being originally designed for handling very large data sets that can be divided easily in parts to be processed independently with limited inter-task communication, Hadoop lacks applicability to a wider usage case. As a result, many projects are under way to enhance Hadoop for different application needs, such as data warehouse applications, machine learning and data mining applications, etc. This thesis is one such research effort in this direction. The goal of the thesis research is to design novel tools and techniques to extend and enhance the large-scale data processing capability of Hadoop/HBase on clouds, and to evaluate their effectiveness in performance tests on prototype implementations. Two main research contributions are described. The first contribution is a light-weight computational workflow system called "CloudWF" for Hadoop. The second contribution is a client library called "HBaseSI" supporting transactional snapshot isolation (SI) in HBase, Hadoop's database component. CloudWF addresses the problem of automating the execution of scientific workflows composed of both MapReduce and legacy applications on clouds with Hadoop/HBase. CloudWF is the first computational workflow system built directly using Hadoop/HBase. It uses novel methods in handling workflow directed acyclic graph decomposition, storing and querying dependencies in HBase sparse tables, transparent file staging, and decentralized workflow execution management relying on the MapReduce framework for task scheduling and fault tolerance. HBaseSI addresses the problem of maintaining strong transactional data consistency in HBase tables. This is the first SI mechanism developed for HBase. HBaseSI uses novel methods in handling distributed transactional management autonomously by individual clients. These methods greatly simplify the design of HBaseSI and can be generalized to other column-oriented stores with similar architecture as HBase. As a result of the simplicity in design, HBaseSI adds low overhead to HBase performance and directly inherits many desirable properties of HBase. HBaseSI is non-intrusive to existing HBase installations and user data, and is designed to work with a large cloud in terms of data size and the number of nodes in the cloud.

Software review is an effective and efficient way for detecting defects in software artifacts. To improve the effectiveness and the efficiency of software review, a variety of software review techniques have been developed. Furthermore, computer support has been used to facilitate the software review process. Accordingly, several software review tools have been developed. Although existing tools provide new solutions to support software review, in general they suffer from a number of shortcomings. In this study, a brief description about major software review techniques is given along with the summary of the process. Additionally, existing tools and their features are briefly explained and a comparison between them is done. This study focuses on the development of a Web based review tool that has a workflow definition capability in order to support every kind of software review processes.

In dieser Arbeit wird ein Ansatz zur automatischen Berechnung und Ausführung von strukturellen Anpassungsmöglichkeiten für Workflows auf Basis von Kontextinformationen entwickelt. Zur Sicherstellung der semantischen Korrektheit der Anpassungsmöglichkeiten werden zwei Arten von Einschränkungen berücksichtigt: Zustandsbezogene Einschränkungen (ZBE) und Aktivitätsabhängigkeiten (AA). ZBEs spezifizieren Einschränkungen zwischen Anpassungsoperationen und dem Ausführungszustand des Workflows. AAs beschreiben temporale Beziehungen zwischen Aktivitäten eines Workflows.

Workflow management is widely accepted as a core technology to support long-term business processes in heterogeneous and distributed environments. However, conventional workflow management systems do not provide sufficient flexibility support to cope with the broad range of failure situations that may occur during workflow execution. In particular, most systems do not allow to dynamically adapt a workflow due to a failure situation, e.g., to dynamically drop or insert execution steps. As a contribution to overcome these limitations, this dissertation introduces the agent-based workflow management system AgentWork. AgentWork supports the definition, the execution and, as its main contribution, the event-oriented and semi-automated dynamic adaptation of workflows. Two strategies for automatic workflow adaptation are provided. Predictive adaptation adapts workflow parts affected by a failure in advance (predictively), typically as soon as the failure is detected. This is advantageous in many situations and gives enough time to meet organizational constraints for adapted workflow parts. Reactive adaptation is typically performed when predictive adaptation is not possible. In this case, adaptation is performed when the affected workflow part is to be executed, e.g., before an activity is executed it is checked whether it is subject to a workflow adaptation such as dropping, postponement or replacement. In particular, the following contributions are provided by AgentWork: A Formal Model for Workflow Definition, Execution, and Estimation: In this context, AgentWork first provides an object-oriented workflow definition language. This language allows for the definition of a workflow’s control and data flow. Furthermore, a workflow’s cooperation with other workflows or workflow systems can be specified. Second, AgentWork provides a precise workflow execution model. This is necessary, as a running workflow usually is a complex collection of concurrent activities and data flow processes, and as failure situations and dynamic adaptations affect running workflows. Furthermore, mechanisms for the estimation of a workflow’s future execution behavior are provided. These mechanisms are of particular importance for predictive adaptation. Mechanisms for Determining and Processing Failure Events and Failure Actions: AgentWork provides mechanisms to decide whether an event constitutes a failure situation and what has to be done to cope with this failure. This is formally achieved by evaluating event-condition-action rules where the event-condition part describes under which condition an event has to be viewed as a failure event. The action part represents the necessary actions needed to cope with the failure. To support the temporal dimension of events and actions, this dissertation provides a novel event-condition-action model based on a temporal object-oriented logic. Mechanisms for the Adaptation of Affected Workflows: In case of failure situations it has to be decided how an affected workflow has to be dynamically adapted on the node and edge level. AgentWork provides a novel approach that combines the two principal strategies reactive adaptation and predictive adaptation. Depending on the context of the failure, the appropriate strategy is selected. Furthermore, control flow adaptation operators are provided which translate failure actions into structural control flow adaptations. Data flow operators adapt the data flow after a control flow adaptation, if necessary. Mechanisms for the Handling of Inter-Workflow Implications of Failure Situations: AgentWork provides novel mechanisms to decide whether a failure situation occurring to a workflow affects other workflows that communicate and cooperate with this workflow. In particular, AgentWork derives the temporal implications of a dynamic adaptation by estimating the duration that will be needed to process the changed workflow definition (in comparison with the original definition). Furthermore, qualitative implications of the dynamic change are determined. For this purpose, so-called quality measuring objects are introduced. All mechanisms provided by AgentWork include that users may interact during the failure handling process. In particular, the user has the possibility to reject or modify suggested workflow adaptations. A Prototypical Implementation: Finally, a prototypical Corba-based implementation of AgentWork is described. This implementation supports the integration of AgentWork into the distributed and heterogeneous environments of real-world organizations such as hospitals or insurance business enterprises.

Universiẗat, Diss.--Duisburg-Essen, 2007.