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An approach for QoS-aware service composition based on genetic algorithms
- In Proc. GECCO ’05
, 2005
"... Web services are rapidly changing the landscape of software engineering. One of the most interesting challenges introduced by web services is represented by Quality Of Service (QoS)–aware composition and late–binding. This allows to bind,at run–time,a service–oriented system with a set of services t ..."
Abstract
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Cited by 160 (7 self)
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Web services are rapidly changing the landscape of software engineering. One of the most interesting challenges introduced by web services is represented by Quality Of Service (QoS)–aware composition and late–binding. This allows to bind,at run–time,a service–oriented system with a set of services that,among those providing the required features, meet some non–functional constraints,and optimize criteria such as the overall cost or response time. In other words, QoS–aware composition can be modeled as an optimization problem. We propose to adopt Genetic Algorithms to this aim. Genetic Algorithms,while being slower than integer programming,represent a more scalable choice,and are more suitable to handle generic QoS attributes. The paper describes our approach and its applicability,advantages and weaknesses,discussing results of some numerical simulations.
QoS-Aware Replanning of Composite Web Services
- In ICWS 2005 Proc
, 2005
"... Run-time service discovery and late-binding constitute some of the most challenging issues of service–oriented software engineering. For late-binding to be effective in the case of composite services, a QoS-aware composition mechanism is needed. This means determining the set of services that, once ..."
Abstract
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Cited by 58 (5 self)
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Run-time service discovery and late-binding constitute some of the most challenging issues of service–oriented software engineering. For late-binding to be effective in the case of composite services, a QoS-aware composition mechanism is needed. This means determining the set of services that, once composed, not only will perform the required functionality, but also will best contribute to achieve the level of QoS promised in Service Level Agreements (SLAs). However, QoS-aware composition relies on estimated QoS values and workflow execution paths previously obtained using a monitoring mechanism. At run-time, the actual QoS values may deviate from the estimations, or the execution path may not be the one foreseen. These changes could increase the risk of breaking SLAs and obtaining a poor QoS. Such a risk could be avoided by replanning the service bindings of the workflow slice still to be executed. This paper proposes an approach to trigger and perform composite service replanning during execution. An evaluation has been performed simulating execution and replanning on a set of composite service workflows.
A Framework for QoS-Aware Binding and Re-Binding of Composite Web Services
"... QoS-aware dynamic binding of composite services provides the capability of binding each service invocation in a composition to a service chosen among a set of functionally equivalent ones to achieve a QoS goal, for example minimizing the response time while limiting the price under a maximum value. ..."
Abstract
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Cited by 53 (2 self)
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QoS-aware dynamic binding of composite services provides the capability of binding each service invocation in a composition to a service chosen among a set of functionally equivalent ones to achieve a QoS goal, for example minimizing the response time while limiting the price under a maximum value. This paper proposes a QoS-aware binding approach based on Genetic Algorithms. The approach includes a feature for early run-time re-binding whenever the actual QoS deviates from initial estimates, or when a service is not available. The approach has been implemented in a framework and empirically assessed through two different service compositions.
A lightweight approach for QoS-aware service composition
- In Proc. 2nd International Conference on Service Oriented Computing (ICSOC’04) - short papers
, 2004
"... One of the most challenging issues of service–centric software engineering is the QoS–aware composition of services. The aim is to search for the optimal set of services that, composed to create a new service, result in the best QoS, under the user or service designer constraints. During service exe ..."
Abstract
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Cited by 31 (6 self)
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One of the most challenging issues of service–centric software engineering is the QoS–aware composition of services. The aim is to search for the optimal set of services that, composed to create a new service, result in the best QoS, under the user or service designer constraints. During service execution, re-planning such a composition may be needed whenever deviations from the QoS estimates occur. Both QoS–aware composition and re-planning may need to be performed in a short time, especially for interactive or real–time systems. This paper proposes a lightweight approach for QoS–aware service composition that uses genetic algorithms for the optimal QoS estimation. Also, the paper presents an algorithm for early triggering service re-planning. If required re-planning is triggered as soon as possible during service execution. The performances of our approach are evaluated by means of numerical simulation. 1.
D-Tree Substitution Grammars
- Computational Linguistics
, 2001
"... Topical developments in software-engineering facilitate the establishment of new design patterns for information systems. In Service-Oriented Architectures (SOA), processes of an information system can be extracted and “out-tasked ” to service providers. KEEN/MCDONALD highlight the changes that are ..."
Abstract
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Cited by 10 (0 self)
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Topical developments in software-engineering facilitate the establishment of new design patterns for information systems. In Service-Oriented Architectures (SOA), processes of an information system can be extracted and “out-tasked ” to service providers. KEEN/MCDONALD highlight the changes that are brought about by such an architecture with their statement „Outtasking […] breaks a company into a portfolio of process-centered operations rather than interlocking departments or functions.” [30]. Examples of technologies that have been developed for this purpose are COM+, CORBA und RMI [55]. With the initiative of Enterprise Application Integration (EAI), web-services turn out in practice to enable a widely spread realization of SOA. With these technological achievements, new management tasks are arising in information systems science. As information
RCOST- Research Centre on Software Technology QoS-Aware Replanning of Composite Web
"... Run-time service discovery and late-binding constitute some of the most challenging issues of service–oriented software engineering. For late-binding to be effective in the case of composite services, a QoS-aware composition mechanism is needed, that is, determining the set of services that, once co ..."
Abstract
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Run-time service discovery and late-binding constitute some of the most challenging issues of service–oriented software engineering. For late-binding to be effective in the case of composite services, a QoS-aware composition mechanism is needed, that is, determining the set of services that, once composed, not only will perform the required functionality, but also will best contribute to achieve the level of QoS promised in Service Level Agreements. However, QoS-aware composition relies on estimated QoS values of the component services and on probabilities for the workflow execution traces. At runtime, the actual QoS values of the individual services may deviate from the estimations and the execution path may not be the one foreseen. These changes could have a drastic impact on the expected overall QoS of the service. Thus, the risk of breaking SLAs and obtaining a poor QoS could be avoided by replanning the service bindings of the workflow part still to be executed. In fact, the new binding could compensate the observed workflow QoS loss, or simply lead to a suboptimal solution still within the SLAs.
Performance, Reliability
"... Web services are rapidly changing the landscape of software engineering. One of the most interesting challenges introduced by web services is represented by Quality Of Service (QoS)–aware composition and late–binding. This allows to bind, at run–time, a service–oriented system with a set of services ..."
Abstract
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Web services are rapidly changing the landscape of software engineering. One of the most interesting challenges introduced by web services is represented by Quality Of Service (QoS)–aware composition and late–binding. This allows to bind, at run–time, a service–oriented system with a set of services that, among those providing the required features, meet some non–functional constraints, and optimize criteria such as the overall cost or response time. In other words, QoS–aware composition can be modeled as an optimization problem. We propose to adopt Genetic Algorithms to this aim. Genetic Algorithms, while being slower than integer programming, represent a more scalable choice, and are more suitable to handle generic QoS attributes. The paper describes our approach and its applicability, advantages and weaknesses, discussing results of some numerical simulations.
Π3 Aims and Scope: The World Wide Web
"... and its associated technologies have become a major implementation and delivery platform for a large variety of applications, ranging from simple institutional information Web sites to sophisticated supply-chain management systems, financial applications, egovernment, distance learning, and entertai ..."
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and its associated technologies have become a major implementation and delivery platform for a large variety of applications, ranging from simple institutional information Web sites to sophisticated supply-chain management systems, financial applications, egovernment, distance learning, and entertainment, among others. Such applications, in addition to their intrinsic functionality, also exhibit the more complex behavior of distributed applications. Recently, there have been some advances towards re-framing the development- both design and implementation- of Web applications as a disciplined and systematic endeavor. However, the vast majority of existing applications have been developed in an ad-hoc way, leading to problems of maintainability, quality and reliability. Web applications are software artifacts, and as such can benefit by making use of established practices stemming from several related disciplines such as Software Engineering, Hypermedia, Information Systems, Human-Computer Interaction and Organizational Science, enabling creation, management and reuse of structures of the information space as well as enhancing the end-user experience. In addition, it has its own characteristics which must be addressed, such as a varied user population, very short development turnaround times, diverse runtime environments, accessibility through multiple devices, etc. Web Engineering is the scientific discipline that studies the theory and practice of constructing Web-based systems and applications. This includes theoretical principles and systematic, disciplined and quantifiable approaches towards the cost-effective development and evolution of high-quality, ubiquitously usable Webbased systems and applications. It fundamentally concerns the technology which enables the construction of
Composite Web Services
"... QoS-aware dynamic binding of composite services provides the capability of binding each service invocation in a composition to a service chosen among a set of functionally equivalent ones to achieve a QoS goal, for example minimizing the response time while limiting the price under a maximum value. ..."
Abstract
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QoS-aware dynamic binding of composite services provides the capability of binding each service invocation in a composition to a service chosen among a set of functionally equivalent ones to achieve a QoS goal, for example minimizing the response time while limiting the price under a maximum value. This paper proposes a QoS-aware binding approach based on Genetic Algorithms. The approach includes a feature for early run-time re-binding whenever the actual QoS deviates from initial estimates, or when a service is not available. The approach has been implemented in a framework and empirically assessed through three different service compositions.
A QoS Perspective on Exception Diagnosis in Service- Oriented Computing
"... Abstract: Unlike object-oriented applications it is difficult to address exceptions in multi-agent systems due to their highly dynamic and autonomous nature. Our previous work has examined exception diagnosis in multi-agent systems based on a heuristic classification method. In this paper, we extend ..."
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Abstract: Unlike object-oriented applications it is difficult to address exceptions in multi-agent systems due to their highly dynamic and autonomous nature. Our previous work has examined exception diagnosis in multi-agent systems based on a heuristic classification method. In this paper, we extend our work by applying an exception diagnosis method to web services (WS) by proposing a unified framework for dealing with exceptions occurring in multi-agent systems as well as in web services. Importantly, we relate the impact of exceptions to Quality of Service (QoS), as exceptions normally degrade the quality of service offered to a service consumer. Our framework consists of a QoS monitoring agent that monitors all interactions taking place between service consumers and service providers. The monitoring agent encodes the knowledge of exceptions, their causes and applies the heuristic classification method for reasoning in order to diagnose underlying causes of monitored exceptions. In this paper, we categorize exceptions into three levels in multi-agent systems: Environment Level Exception; Knowledge Level Exception and Social Level Exception. This paper also discusses different classes of exceptions in web services based on the web service stack.
