6 research outputs found

    Hochleistungs-Transaktionssysteme: Konzepte und Entwicklungen moderner Datenbankarchitekturen

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    Das Buch richtet sich an Informatiker in Studium, Lehre, Forschung und Entwicklung, die an neueren Entwicklungen im Bereich von Transaktions- und Datenbanksystemen interessiert sind. Es entspricht einer ĂŒberarbeiteten Version meiner im Februar 1993 vom Fachbereich Informatik der UniversitĂ€t Kaiserslautern angenommenen Habilitationsschrift. Neben der PrĂ€sentation neuer Forschungsergebnisse erfolgen eine breite EinfĂŒhrung in die Thematik sowie ĂŒberblicksartige Behandlung verschiedener RealisierungsansĂ€tze, wobei auf eine möglichst allgemeinverstĂ€ndliche Darstellung Wert gelegt wurde. Der Text wurde durchgehend mit Marginalien versehen, welche den Aufbau der Kapitel zusĂ€tzlich verdeutlichen und eine schnelle Lokalisierung bestimmter Inhalte unterstĂŒtzen sollen

    Simulation product fidelity: a qualitative & quantitative system engineering approach

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    La modĂ©lisation informatique et la simulation sont des activitĂ©s de plus en plus rĂ©pandues lors de la conception de systĂšmes complexes et critiques tels que ceux embarquĂ©s dans les avions. Une proposition pour la conception et rĂ©alisation d'abstractions compatibles avec les objectifs de simulation est prĂ©sentĂ©e basĂ©s sur la thĂ©orie de l'informatique, le contrĂŽle et le systĂšme des concepts d'ingĂ©nierie. Il adresse deux problĂšmes fondamentaux de fidĂ©litĂ© dans la simulation, c'est-Ă -dire, pour une spĂ©cification du systĂšme et quelques propriĂ©tĂ©s d'intĂ©rĂȘt, comment extraire des abstractions pour dĂ©finir une architecture de produit de simulation et jusqu'oĂč quel point le comportement du modĂšle de simulation reprĂ©sente la spĂ©cification du systĂšme. Une notion gĂ©nĂ©rale de cette fidĂ©litĂ© de la simulation, tant architecturale et comportementale, est expliquĂ©e dans les notions du cadre expĂ©rimental et discutĂ© dans le contexte des abstractions de modĂ©lisation et des relations d'inclusion. Une approche semi-formelle basĂ©e sur l'ontologie pour construire et dĂ©finir l'architecture de produit de simulation est proposĂ©e et dĂ©montrĂ©e sur une Ă©tude d'Ă©chelle industrielle. Une approche formelle basĂ©e sur le jeu thĂ©orique et mĂ©thode formelle est proposĂ©e pour diffĂ©rentes classes de modĂšles des systĂšmes et des simulations avec un dĂ©veloppement d'outils de prototype et cas des Ă©tudes. Les problĂšmes dans la recherche et implĂ©mentation de ce cadre de fidĂ©litĂ© sont discutĂ©es particuliĂšrement dans un contexte industriel.In using Modeling and Simulation for the system Verification & Validation activities, often the difficulty is finding and implementing consistent abstractions to model the system being simulated with respect to the simulation requirements. A proposition for the unified design and implementation of modeling abstractions consistent with the simulation objectives based on the computer science, control and system engineering concepts is presented. It addresses two fundamental problems of fidelity in simulation, namely, for a given system specification and some properties of interest, how to extract modeling abstractions to define a simulation product architecture and how far does the behaviour of the simulation model represents the system specification. A general notion of this simulation fidelity, both architectural and behavioural, in system verification and validation is explained in the established notions of the experimental frame and discussed in the context of modeling abstractions and inclusion relations. A semi-formal ontology based domain model approach to build and define the simulation product architecture is proposed with a real industrial scale study. A formal approach based on game theoretic quantitative system refinement notions is proposed for different class of system and simulation models with a prototype tool development and case studies. Challenges in research and implementation of this formal and semi-formal fidelity framework especially in an industrial context are discussed

    Knowledge and Management Models for Sustainable Growth

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    In the last years sustainability has become a topic of global concern and a key issue in the strategic agenda of both business organizations and public authorities and organisations. Significant changes in business landscape, the emergence of new technology, including social media, the pressure of new social concerns, have called into question established conceptualizations of competitiveness, wealth creation and growth. New and unaddressed set of issues regarding how private and public organisations manage and invest their resources to create sustainable value have brought to light. In particular the increasing focus on environmental and social themes has suggested new dimensions to be taken into account in the value creation dynamics, both at organisations and communities level. For companies the need of integrating corporate social and environmental responsibility issues into strategy and daily business operations, pose profound challenges, which, in turn, involve numerous processes and complex decisions influenced by many stakeholders. Facing these challenges calls for the creation, use and exploitation of new knowledge as well as the development of proper management models, approaches and tools aimed to contribute to the development and realization of environmentally and socially sustainable business strategies and practices

    Scalable and Highly Available Database Systems in the Cloud

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    Cloud computing allows users to tap into a massive pool of shared computing resources such as servers, storage, and network. These resources are provided as a service to the users allowing them to “plug into the cloud” similar to a utility grid. The promise of the cloud is to free users from the tedious and often complex task of managing and provisioning computing resources to run applications. At the same time, the cloud brings several additional benefits including: a pay-as-you-go cost model, easier deployment of applications, elastic scalability, high availability, and a more robust and secure infrastructure. One important class of applications that users are increasingly deploying in the cloud is database management systems. Database management systems differ from other types of applications in that they manage large amounts of state that is frequently updated, and that must be kept consistent at all scales and in the presence of failure. This makes it difficult to provide scalability and high availability for database systems in the cloud. In this thesis, we show how we can exploit cloud technologies and relational database systems to provide a highly available and scalable database service in the cloud. The first part of the thesis presents RemusDB, a reliable, cost-effective high availability solution that is implemented as a service provided by the virtualization platform. RemusDB can make any database system highly available with little or no code modifications by exploiting the capabilities of virtualization. In the second part of the thesis, we present two systems that aim to provide elastic scalability for database systems in the cloud using two very different approaches. The three systems presented in this thesis bring us closer to the goal of building a scalable and reliable transactional database service in the cloud

    Modelling parallel database management systems for performance prediction

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    Abstract unavailable please refer to PD

    The role of the host in a cooperating mainframe and workstation environment, volumes 1 and 2

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    In recent years, advancements made in computer systems have prompted a move from centralized computing based on timesharing a large mainframe computer to distributed computing based on a connected set of engineering workstations. A major factor in this advancement is the increased performance and lower cost of engineering workstations. The shift to distributed computing from centralized computing has led to challenges associated with the residency of application programs within the system. In a combined system of multiple engineering workstations attached to a mainframe host, the question arises as to how does a system designer assign applications between the larger mainframe host and the smaller, yet powerful, workstation. The concepts related to real time data processing are analyzed and systems are displayed which use a host mainframe and a number of engineering workstations interconnected by a local area network. In most cases, distributed systems can be classified as having a single function or multiple functions and as executing programs in real time or nonreal time. In a system of multiple computers, the degree of autonomy of the computers is important; a system with one master control computer generally differs in reliability, performance, and complexity from a system in which all computers share the control. This research is concerned with generating general criteria principles for software residency decisions (host or workstation) for a diverse yet coupled group of users (the clustered workstations) which may need the use of a shared resource (the mainframe) to perform their functions
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