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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.
1

Modélisation à base de Composants de Systèmes Temps réel Hétérogènes en BIP

Basu, Ananda 15 December 2008 (has links) (PDF)
We present the BIP component framework for component-based construction of real-time systems from heterogeneous components. BIP stands for Behavior, Interaction and Priority, the three main elements for building components. It considers that systems can be obtained by composition of 3-layered components, where the lowest layer represents behavior as a set of transitions with triggers and actions; the intermediate level is the set of the interactions between the transitions of the behavior level, and the upper level is a set of dynamic priority rules. BIP has a rigorous formal semantics, and supports a system construction methodology based on a parameterized composition operator on components. The use of a layered composition operator allows incremental construction. The system construction process can be viewed as a sequence of transformations in a three-dimensional space of Behavior X Interaction X Priority, and provides a basis for the study of property preserving transformations between subclasses of systems such as untimed/timed, asynchronous/synchronous. We also provide a distributed semantics for systems in BIP, using a partial state model, and show the use of an auxiliary predicate called Oracle to preserve observational equivalence with respect to the centralized semantics. We present an implementation of BIP as a tool chain that allows modeling, static analysis and execution of BIP descriptions on a dedicated engine. Three different implementations for the engine have been provided, a centralized enumerative engine, a centralized symbolic engine and a distributed engine. We illustrate the use of the tool chain for two major application domains, Software Componentization, and Modeling mixed hw/sw systems.
2

Komponentinis IS modelio transformavimas / Component based IS model transformation

Gurgždys, Virgilijus 19 January 2007 (has links)
The traditional approaches to engineering of information systems focus on identifying business requirements and delivering the specific functionality required to automate some activities. Not enough attention is being attached to how the created system will interact with the rest of the business. As a result, there is often a gap between the business requirements and the systems implemented to support them. To bridge this gap, many organizations are developing enterprise architecture to provide a holistic vision of how systems will support their business. Model-driven architecture (MDA) focuses on modelling activities in software development process and shifts the software development process from the writing code to the modelling activities. MDA separates the business level from the technological platform which implements information system. The key feature of the model-driven architecture is its ability to transform automatically the platform-independent model (PIM) into the platform-specific model (PSM). MDA uses modelling languages as programming languages Using interface-based programming is the evolution of the object-oriented programming and design. The interfaces have made the software design more adaptable to the rapid changes of the business environment. While using interfaces, software systems achieve reusability, extensibility and maintainability. The CBD approaches use the interface-based design idea and therefore have advantages such as more effective... [to full text]
3

Towards Model-Based Fault Management for Computing Systems

Jia, Rui 07 May 2016 (has links)
Large scale distributed computing systems have been extensively utilized to host critical applications in the fields of national defense, finance, scientific research, commerce, etc. However, applications in distributed systems face the risk of service outages due to inevitable faults. Without proper fault management methods, faults can lead to significant revenue loss and degradation of Quality of Service (QoS). An ideal fault management solution should guarantee fast and accurate fault diagnosis, scalability in distributed systems, portability for a variety of systems, and the versatility of recovering different types of faults. This dissertation presents a model-based fault management structure which automatically recovers computing systems from faults. This structure can recover a system from common faults while minimizing the impact on the system’s QoS. It covers all stages of fault management including fault detection, identification and recovery. It also has the flexibility to incorporate various fault diagnosis methods. When faults occur, the approach identifies fault types and intensity, and it accordingly computes the optimal recovery plan with minimum performance degradation, based on a cost function that defines performance objectives and a predictive control algorithm. The fault management approach has been verified on a centralized Web application testbed and a distributed big data processing testbed with four types of simulated faults: memory leak, network congestion, CPU hog and disk failure. The feasibility of the fault recovery control algorithm is also verified. Simulation results show that our approach enabled effective automatic recovery from faults. Performance evaluation reveals that CPU and memory overhead of the fault management process is negligible. To let domain engineers conveniently apply the proposed fault management structure on their specific systems, a component-based modeling environment is developed. The meta-model of the fault management structure is developed with Unified Modeling Language as an abstract of a general fault recovery solution for computing systems. It defines the fundamental reusable components that comprise such a system, including the connections among them, attributes of each component and constraints. The meta-model can be interpreted into a userriendly graphic modeling environment for creating application models of practical domain specific systems and generating executable codes on them.
4

Advancing the Cyberinfrastructure for Integrated Water Resources Modeling

Buahin, Caleb A. 01 December 2017 (has links)
Like other scientists, hydrologists encode mathematical formulations that simulate various hydrologic processes as computer programs so that problems with water resource management that would otherwise be manually intractable can be solved efficiently. These computer models are typically developed to answer specific questions within a specific study domain. For example, one computer model may be developed to solve for magnitudes of water flow and water levels in an aquifer while another may be developed to solve for magnitudes of water flow through a water distribution network of pipes and reservoirs. Interactions between different processes are often ignored or are approximated using overly simplistic assumptions. The increasing complexity of the water resources challenges society faces, including stresses from variable climate and land use change, means that some of these models need to be stitched together so that these challenges are not evaluated myopically from the perspective of a single research discipline or study domain. The research in this dissertation presents an investigation of the various approaches and technologies that can be used to support model integration. The research delves into some of the computational challenges associated with model integration and suggests approaches for dealing with these challenges. Finally, it advances new software that provides data structures that water resources modelers are more accustomed to and allows them to take advantage of advanced computing resources for efficient simulations.
5

Modélisation explicite de l'adaptation sémantique entre modèles de calcul. / Explicit modeling of the semantic adaptation between models of computation

Dogui, Ayman 18 December 2013 (has links)
Ce travail traite de la modélisation de systèmes complexes constitués de plusieurs composants impliquant des domaines techniques différents. Il se place dans le contexte de la modélisation hétérogène hiérarchique, selon l’approche à base de modèles de calcul. Chaque composant faisant appel à un domaine technique particulier, son comportement peut être modélisé selon un paradigme de modélisation approprié, avec une sémantique différente de celle des autres composants. La modélisation du système global, qui intègre les modèles hétérogènes de ces composants, nécessite donc une adaptation sémantique permettant l’échange entre les divers sous-modèles.Ce travail propose une approche de modélisation de l’adaptation sémantique où les sémantiques du temps et du contrôle sont explicitement spécifiées par le concepteur en définissant des relations sur les occurrences d’évènements d’une part et sur les étiquettes temporelles de ces occurrences d’autre part. Cette approche est intégrée dans la plateforme ModHel’X et testée sur un cas d’étude : un modèle de lève-vitre électrique. / This work takes place in the context of hierarchical heterogeneous modeling using the model of computation approach in order to model complex systems which includes several components from different technical fields.Each of these components is usually designed according to a modeling paradigm that suits the technical domain and is based on specific semantics. Therefore, the overall system, which integrates the heterogeneous models of the components, requires semantic adaptation to ensure proper communication between its various sub-models.In this context, the aim of this thesis is to propose a new approach of semantic adaptation modeling where the semantic adaptation of time and control is specified by defining relationships between the occurrences of events as well as the time tags of these occurrences. This approach was integrated into the ModHel’X platform and tested on the case study of a power window system.
6

MobIS 2010 - Modellierung betrieblicher Informationssysteme, Modellgestütztes Management

10 December 2010 (has links) (PDF)
This volume contains contribution form the refereed “MobIS 2010” main program and selected papers of its tracks. The conference on information systems modeling was held in Dresden September 15-17, 2010. The guiding theme for MobIS 2010 focused on modeling topics between model-based management and component and service engineering.
7

Pulp mill heat and mass balance model : Exploring the benefits and possibilities of process modelling as an applied method in a case study

Mählkvist, Simon, Pontus, Netzell January 2018 (has links)
This thesis focused on the modelling of a pulping process. The purpose was to see if an accurate model can be crated based on relatively simple premises and if the errors can be identified or analysed. To realise this, the authors conducted a literature study to identify the current state of the art regarding the chemical pulping process. In addition, flow charts and sample data from a case study were examined. Based on the literature review and case study, model assumptions were derived. The model is divided into sixteen components. Where mixing occurs, lumped conditions are assumed. The model has five validation points, four of which are temperatures and a mass flowrate. These are shown as deviations from the measured values. In conclusions, it was the model could produce stable results over a narrow time frame. More so if the transition period at the start of the simulation is overlooked. Several new model assumptions are presented with the purpose to increase accuracy e.g. account for the components ability to store mass.
8

MobIS 2010 - Modellierung betrieblicher Informationssysteme, Modellgestütztes Management: 15.-17. September 2010 in Dresden, Germany

Esswein, Werner, Turowski, Klaus, Juhrisch, Martin January 2010 (has links)
This volume contains contribution form the refereed “MobIS 2010” main program and selected papers of its tracks. The conference on information systems modeling was held in Dresden September 15-17, 2010. The guiding theme for MobIS 2010 focused on modeling topics between model-based management and component and service engineering.:Vorwort..................................................................................................................7 Modellgestütztes Management Esswein Werner, Stark Jeannette, Schlieter Hannes The selection of modeling grammars...................................................................13 Trojahner Iris, Weller Jens, Fürstenau Bärbel, Esswein Werner Der Einfluss von Modellierungswerkzeugen auf Qualität und Quantität von Modellen – Eine empirische Untersuchung.........................................................29 Weller Jens, Helbig Michaela, Großmann Knut Eine Methode fu!r den praktischen Einsatz von Konfigurationsmanagement in verteilten Modellierungsprojekten.......................................................................47 Fengel Janina, Rebstock Michael Domänensemantik-orientierte Integration heterogener konzeptueller Modelle................................................................................................................63 Bögel Stephan, Esswein Werner Vertikale Modellintegration in Rahmenwerken – Evaluation von Integrationsansätzen und Untersuchung der Implementierbarkeit anhand eines Fallbeispiels.........................................................................................................79 Fellmann Michael, Hogrebe Frank, Thomas Oliver, Nüttgens Markus An ontology-driven approach to support semantic verification in business process modeling.................................................................................................99 Juhrisch Martin, Dietz Gunnar Context-based Modeling: Introducing a Novel Modeling Approach................111 Strecker Stefan, Heise David, Frank Ulrich Toward modeling constructs for audit risk assessment: Reflections on internal controls modeling..............................................................................................131 Schlieter Hannes, Bürger Maik, Esswein Werner Konstruktion eines adaptiven Referenzmodells für den ambulanten Sektor.....149 Deindl Matthias, Naß Eric, Beckhoff Tim Anwendung der enhanced Telecom Operations Map auf Dienstleistungsunternehmen in der Stromwirtschaft am Beispiel eines Prozesses im Bereich Messwesen.........................................................................................................171 Komponentenorientierte betriebliche Anwendungssysteme Schrödl Holger Service- und komponentenorientierte Informationssystemarchitekturen für die strategische Beschaffung von hybriden Produkten – ein Vergleichsrahmen.....................................................................................195 Houy Constantin, Reiter Markus, Fettke Peter, Loos Peter Potentiale serviceorientierter Architekturen für Software-Werkzeuge des Geschäftsprozessmanagements..........................................................................211 Sadek Tim, Meuris Daniel Datentechnische Integration und Visualisierung von Anforderungen innerhalb von CAD-Systemen...........................................................................................229

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