93 research outputs found

    Web Services Support for Dynamic Business Process Outsourcing

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    Outsourcing of business processes is crucial for organizations to be effective, efficient and flexible. To meet fast-changing market conditions, dynamic outsourcing is required, in which business relationships are established and enacted on-the-fly in an adaptive, fine-grained way unrestricted by geographic distance. This requires automated means for both the establishment of outsourcing relationships and for the enactment of services performed in these relationships over electronic channels. Due to wide industry support and the underlying model of loose coupling of services, Web services increasingly become the mechanism of choice to connect organizations across organizational boundaries. This paper analyzes to which extent Web services support the dynamic process outsourcing paradigm. We discuss contract -based dynamic business process outsourcing to define requirements and then introduce the Web services framework. Based on this, we investigate the match between the two. We observe that the Web services framework requires further support for cross - organizational business processes and mechanisms for contracting, QoS management and process-based transaction support and suggest ways to fill those gaps

    An interoperable and self-adaptive approach for SLA-based service virtualization in heterogeneous Cloud environments

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    Cloud computing is a newly emerged computing infrastructure that builds on the latest achievements of diverse research areas, such as Grid computing, Service-oriented computing, business process management and virtualization. An important characteristic of Cloud-based services is the provision of non-functional guarantees in the form of Service Level Agreements (SLAs), such as guarantees on execution time or price. However, due to system malfunctions, changing workload conditions, hard- and software failures, established SLAs can be violated. In order to avoid costly SLA violations, flexible and adaptive SLA attainment strategies are needed. In this paper we present a self-manageable architecture for SLA-based service virtualization that provides a way to ease interoperable service executions in a diverse, heterogeneous, distributed and virtualized world of services. We demonstrate in this paper that the combination of negotiation, brokering and deployment using SLA-aware extensions and autonomic computing principles are required for achieving reliable and efficient service operation in distributed environments. © 2012 Elsevier B.V. All rights reserved

    Automated SLA Negotiation Framework for Cloud Computing

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    Generic Methods for Adaptive Management of Service Level Agreements in Cloud Computing

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    The adoption of cloud computing to build and deliver application services has been nothing less than phenomenal. Service oriented systems are being built using disparate sources composed of web services, replicable datastores, messaging, monitoring and analytics functions and more. Clouds augment these systems with advanced features such as high availability, customer affinity and autoscaling on a fair pay-per-use cost model. The challenge lies in using the utility paradigm of cloud beyond its current exploit. Major trends show that multi-domain synergies are creating added-value service propositions. This raises two questions on autonomic behaviors, which are specifically ad- dressed by this thesis. The first question deals with mechanism design that brings the customer and provider(s) together in the procurement process. The purpose is that considering customer requirements for quality of service and other non functional properties, service dependencies need to be efficiently resolved and legally stipulated. The second question deals with effective management of cloud infrastructures such that commitments to customers are fulfilled and the infrastructure is optimally operated in accordance with provider policies. This thesis finds motivation in Service Level Agreements (SLAs) to answer these questions. The role of SLAs is explored as instruments to build and maintain trust in an economy where services are increasingly interdependent. The thesis takes a wholesome approach and develops generic methods to automate SLA lifecycle management, by identifying and solving relevant research problems. The methods afford adaptiveness in changing business landscape and can be localized through policy based controls. A thematic vision that emerges from this work is that business models, services and the delivery technology are in- dependent concepts that can be finely knitted together by SLAs. Experimental evaluations support the message of this thesis, that exploiting SLAs as foundations for market innovation and infrastructure governance indeed holds win-win opportunities for both cloud customers and cloud providers

    Automation of The SLA Life Cycle in Cloud Computing

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    Cloud computing has become a prominent paradigm to offer on-demand services for softwares, infrastructures and platforms. Cloud services are contracted by a service level agreement (SLA) between a cloud service provider (CSP) and a cloud service user (CSU) which contains service definitions, quality of service (QoS) parameters, guarantees and obligations. Cloud service providers mostly offer SLAs in descriptive format which is not directly consumable by a machine or a system. The SLA written in natural language may impede the utility of rapid elasticity in a cloud service. Manual management of SLAs with growing usage of cloud services can be a challenging, erroneous and tedious task especially for the CSUs acquiring multiple cloud services. The necessity of automating the complete SLA life cycle (which includes SLA description in machine readable format, negotiation, monitoring and management) becomes imminent due to complex requirements for the precise measurement of QoS parameters. Current approaches toward automating the complete SLA life cycle, lack in standardization, completeness and applicability to cloud services. Automation of different phases of the SLA life cycle (e.g. negotiation, monitoring and management) is dependent on the availability of a machine readable SLA. In this work, a structural specification for the SLAs in cloud computing (S3LACC in short) is presented which is designed specifically for cloud services, covers complete SLA life cycle and conforms with the available standards. A time efficient SLA negotiation technique is accomplished (based on the S3LACC) for concurrently negotiating with multiple CSPs. After successful negotiation process, next leading task in the SLA life cycle is to monitor the cloud services for ensuring the quality of service according to the agreed SLA. A distributed monitoring approach for the cloud SLAs is presented, in this work, which is suitable for services being used at single or multiple locations. The proposed approach reduces the number of communications of SLA violations to a monitoring coordinator by eliminating the unnecessary communications. The presented work on the complete SLA life cycle automation is evaluated and validated with the help of use cases, experiments and simulations

    Central and Eastern Europe’s dependence on Russian gas, western CIS transit states and the quest for diversification through the Southern Corridor

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    Debt and development. The Courier No. 97, May/June 1986

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    Supporting SLA Provisioning in Grids by Risk Management Processes

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    Gridtechnologien haben heutzutage einen hohen Entwicklungsstand erreicht, aber fĂŒr die Etablierung eines kommerziellen Grids ist es erforderlich, Defizite in den Bereichen Sicherheit, VertrauenswĂŒrdigkeit und VerlĂ€sslichkeit zu beheben. Anwender fordern eine AusfĂŒhrung ihrer Applikation (Grid Jobs) gemĂ€ĂŸ einer gewĂŒnschten PrioritĂ€t und QualitĂ€t. Um vertraglich derartige Aspekte einzufordern, können Service Level Agreements (SLAs) zwischen Dienstbenutzern und Dienstanbietern verhandelt werden. Dienstanbieter kennen jedoch die UnzuverlĂ€ssigkeit von Grid Ressourcen und sind daher vorsichtig, strenge Forderungen zu akzeptieren und entsprechende QualitĂ€ten zu garantieren. Können strenge Forderungen jedoch nicht vertraglich vereinbart werden, so bevorzugen es viele Anwender, eigene Rechenressourcen zu verwenden. Zwar ist die Unterhaltung eigener Ressourcen in vielen FĂ€llen teurer, aber sie haben die Kontrolle ĂŒber ihre Applikation, was ihnen mehr Sicherheit bietet. FĂŒr die Etablierung eines kommerziellen Grids ist es daher unerlĂ€sslich, dass Grid Provider auch strenge SLAs akzeptieren. Damit Provider strenge SLAs akzeptieren können, benötigen sie AbschĂ€tzungen dafĂŒr, dass sie die SLA nicht erfĂŒllen können (Risikoberechnung). Des Weiteren sollten solche AbschĂ€tzungen als Entscheidungskriterium bei der Ressourcenallokation oder Initiierung von Fehlertoleranzmaßnahmen fungieren (Risikomanagement). Diese Arbeit integriert die Betrachtung von Risiken in die AblĂ€ufe des Providers, die in die Erbringung von SLAs involviert sind. WĂ€hrend der SLA Verhandlung wird evaluiert welche Ressourcen fĂŒr die Diensterbringung verwendet werden. Basierend darauf wird die Fehlerwahrscheinlichkeit dieser Ressourcen und der SLA Erbringung im Gesamten berechnet. Falls die mögliche Fehlerwahrscheinlichkeit zu hoch ist, können risikoreduzierende Maßnahmen durchgefĂŒhrt werden, so dass die SLA akzeptiert werden kann. Die berechnete Fehlerwahrscheinlichkeit wird von Provider und Benutzer ebenfalls bei der Bestimmung des Preises und der Konventionalstrafe betrachtet. Nach dem Vertragsabschluss ist es fĂŒr die Vermeidung von SLA Verletzungen aus Grid Provider Sicht essentiell, RessourcenausfĂ€lle kompensieren zu können. Die Verwendung von Fehlertoleranzmaßnahmen in Zusammenhang mit einer Risikobetrachtung unterstĂŒtzt Grid Provider bei der BewĂ€ltigung dieser Aufgabe. Risikomanagementprozesse werden dabei direkt mit dem Ressourcenmanagement verknĂŒpft und sind nicht sichtbar fĂŒr Anwender. Ein wichtiger Aspekt des entwickelten Risikomanagements sind selbstorganisierende Mechanismen, die eine Fehlertoleranzmaßnahme oder eine Kette solcher initiieren, um auf InstabilitĂ€ten oder AusfĂ€lle von Ressourcen zu reagieren. FĂŒr kommerzielle Grid Provider ist die Betrachtung finanzieller Aspekte im Ressourcenbetrieb und in der Diensterbringung stets von hoher Bedeutung. Folglich werden alle Entscheidungen unter BerĂŒcksichtigung finanzieller Aspekte getroffen, wie zum Beispiel der Gewinnmarge, den Kosten fĂŒr eine Fehlertoleranzmaßnahme sowie dem erwarteten Profit fĂŒr eine JobausfĂŒhrung. Zusammengefasst gilt die Integration von Risikomanagement in die AblĂ€ufe eines Grid Providers als initialer Schritt fĂŒr ein risikobetrachtendes Grid. Es wird die Transparenz, ZuverlĂ€ssigkeit und VertrauenswĂŒrdigkeit steigern und dient als objektives Kriterium fĂŒr Entscheidungsprozesse im Ressourcenmanagement. Ein integriertes Risikomanagement bringt enorme Vorteile sowohl wĂ€hrend der SLA Verhandlung als auch nach Vertragsabschluss - und damit insgesamt fĂŒr die Diensterbringung im Rahmen von SLAs.Grid technologies have reached a high level of development, however core shortcomings have been identified relating to security, trust, and dependability of the Grid which reduce its appeal to potential commercial adopters. Users require a job execution with a desired priority and quality. In order to stipulate such requirements, Service Level Agreements (SLA) can be negotiated. These are a powerful instrument enabling the specification of the business relationships between service providers and service users in detail. However, providers are aware of various threats for SLA violations and are reluctant to adopt a mechanism which requires them to meet strict requirements and to guarantee associated quality constraints. If strict guarantees cannot be agreed by contract, many users prefer to operate their own resources instead of using the Grid. This is more expensive but they control their applications, which removes the issues of trust and ensures dependability concerning its successful completion. To establish a commercial Grid environment, it is essential that Grid providers are prepared to accept an approach involving SLAs with associated guarantees. In order to enable providers to accept such SLAs, they need estimates of the likelihood that they are unable to fulfill an SLA, i. e. Risk Assessment. Furthermore the resource management should take into account such estimations when allocating resources or initiating fault-tolerance mechanisms, i. e. Risk Management. This work integrates risk awareness in the provider’s processes which are involved in SLA provisioning: During SLA negotiation they evaluate which resources can be used for service provisioning and estimate the Probability of Failure (PoF) of resources and of fulfilling the SLA. If the estimated PoF is too high, then, by applying risk reduction mechanisms, the provider may be able to reduce it sufficiently to accept the SLA. The estimated PoF will also be considered by the service provider and service consumer when determining the revenue and the contractual penalty. Compared to a service request requiring a relatively low quality of service, providing a more reliable service requires to receive a higher price since more guarantees have to be ensured. If a more reliable service is provided, the consumer might also define a higher contractual penalty. Thus, the PoF is an additional decision making element in the SLA negotiation since it enables end-users to compare different SLA offers by an objective measurement. When providers have accepted an SLA, they have to be able to compensate for resource failures in order to prevent SLA violations. The usage of fault-tolerance mechanisms combined with risk awareness support Grid providers in this task. The Risk Management processes are interlaced with the resource management and thereby transparent for Grid service consumers. An important aspect of the Risk Management developed for the Grid are self-organising mechanisms, which initiate a fault-tolerance action or a chain of them, in order to manage resource instabilities or resource outages. Decisions are made on the basis of financial considerations, such as the profit margin, the cost for performing fault-tolerance, and the expected profit when executing a job. Taking into account such financial factors is of high importance for commercial Grid providers. In conclusion, the integration of Risk Management in the processes of Grid providers is the initial step towards a risk aware Grid. It will increase transparency, reliability, and trust and provides an objective basis for decision processes in the resource management. Risk Management is integrated to address the SLA negotiation as well as the post-negotiation phase and thereby improves the SLA provisioning process in general

    Problematic Situations, Preference Change, and Negotiations: A Philosophical Approach

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    For many of the large-scale problems facing humanity, individuals lack the power to address them on their own. We might call upon group agents such as states or corporations to solve them for us. Problems such as climate change, however, are of such a scope and magnitude that no single group agent can deal with them effectively. To achieve a cooperative solution, groups must negotiate with one another on how to address these problems. Contributing to our understanding of how humanity can deal with such large-scale problems, the present thesis offers a theory of negotiating group agents. After an introduction, chapters two, three, and four offer a philosophical reconstruction of the sociological Negotiated Order approach. At the core of these chapters is a pragmatist theory of motivational change in social contexts, which I contrast with standard rational choice theory. The Negotiated Order approach argues that many social phenomena, such as organisations, function based on motivational change occurring in the context of informal negotiations. Chapter five discusses group agency and argues that functionalist accounts of group agency are a promising approach for extending the Negotiated Order approach. The sixth and final chapter returns to the original motivation for developing a theory of negotiating group agents. It shows that in the case of climate change negotiations, the Negotiated Order account offers a different and promising perspective than standard rational choice models. In addition, the thesis includes an appendix which discusses Dewey’s theory of choice and proposes a way of formalising its pragmatist take on preference change
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