@conference {vas2009d,
	title = {A framework for adaptation in secure web services},
	booktitle = {Proceedings of MCIS 2009},
	year = {2009},
	month = {9},
	abstract = {In the context of service-oriented computing, the introduction of the Quality-of-Service (QoS) aspect leads to the need to adapt the execution of programs to the QoS requirements of the particular execution. This is typically achieved by finding alternate services that are functionally equivalent to the ones originally specified in the program and whose QoS characteristics closely match the requirements, and invoking the alternate services instead of the originally specified ones; the same approach can also be employed for tackling exceptions. The techniques proposed insofar, however, cannot be applied in a secure context, where data are encrypted and signed for the originally intended recipient. In this paper, we introduce a framework for facilitating adaptation in the context of secure SOA.},
	author = {Costas Vassilakis and Christos Kareliotis}
}
@article {Kareliotis2009284,
	title = {IQoS-aware exception resolution for BPEL processes: A middleware-based framework and performance evaluation},
	journal = {International Journal of Web and Grid Services},
	volume = {5},
	number = {3},
	year = {2009},
	note = {cited By (since 1996) 0},
	pages = {284-320},
	abstract = {Web Services Business Process Execution Language (WS-BPEL) is widely used nowadays for specifying and executing composite business processes. During the execution, however, of such business processes, a number of faults stemming from the nature of SOA may occur. The WS-BPEL scenario designer must therefore use the provisions offered by WS-BPEL to catch these exceptions and resolve them. The system fault handler specification, however, is an additional task for the WS scenario designer, while the presence of such handlers within the scenario necessitates extra maintenance activities. In this paper, we propose a middleware-based framework for system exception resolution, which undertakes the tasks of failure interception, discovery of alternative services and their invocation. The process of selecting the alternative services can be driven by process consumer-specified Quality of Service (QoS) policy. Moreover, the middleware arranges for bridging syntactic differences between the originally invoked services and functionally equivalent replacements to it, by employing XSLT-based transformations. The middleware is deployed and maintained independently of the WS-BPEL scenarios, thus removing the need for specifying and maintaining system fault handlers within the scenarios. We also present performance measures, establishing that the overhead imposed by the addition of the proposed middleware layer is minimal. Copyright Β{\textcopyright} 2009, Inderscience Publishers.},
	keywords = {Ad hoc networks, BPEL process, Exception handling, Exception resolution, Middleware, Performance metrics, QoS, Quality control, Quality of service, Scalability, Telecommunication services, Web services},
	doi = {10.1504/IJWGS.2009.028346},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70349462474\&partnerID=40\&md5=4511b42fde076617cd6ac0139e3f588d},
	author = {Christos Kareliotis and Costas Vassilakis and S. Rouvas and P. Georgiadis}
}
@conference {Christos2009271,
	title = {QoS-driven adaptation of BPEL scenario execution},
	booktitle = {2009 IEEE International Conference on Web Services, ICWS 2009},
	year = {2009},
	note = {cited By (since 1996) 0},
	month = {7},
	pages = {271-278},
	abstract = {BPEL/WSBPEL is the predominant approach for combining individual web services into integrated business processes, allowing for the specification of their sequence, control flow and data exchanges. BPEL however does not include mechanisms for considering the invoked services{\textquoteright} Quality of Service (QoS) parameters and thus BPEL scenarios can neither tailor their execution to the individual user{\textquoteright}s needs or adapt to the highly dynamic environment of the WEB, where new services may be deployed, old ones withdrawn or existing ones changing their QoS parameters. Moreover, infrastructure failures in the distributed environment of the web introduce an additional source of failures that must be considered in the context of QoS-aware service execution. In this work we propose a framework for addressing the issues identified above; the framework allows the users to specify the QoS parameters that they require and it undertakes the task of locating and invoking suitable services. Finally, the proposed framework intercepts and resolves faults occurring during service invocation, respecting the QoS restrictions specified by the consumer. Β{\textcopyright} 2009 IEEE.},
	keywords = {Adaptive execution, BPEL, Control flows, Data exchange, Distributed environments, Dynamic environments, Infrastructure failures, Integrated business, New services, Performance evaliation, QoS parameters, Quality of service, Quality of Service parameters, Service execution, Service invocation, Web services},
	doi = {10.1109/ICWS.2009.80},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70449472686\&partnerID=40\&md5=5303ebeff04a4e7a062f77209521d561},
	author = {Christos Kareliotis and Costas Vassilakis and S. Rouvas and P. Georgiadis}
}
@conference {Christos2008248,
	title = {Exception resolution for BPEL processes: A middleware-based framework and performance evaluation},
	booktitle = {Proceedings of the 10th International Conference on Information Integration and Web-based Applications and Services, iiWAS 2008},
	year = {2008},
	note = {cited By (since 1996) 0},
	month = {12},
	pages = {248-256},
	abstract = {WS-BPEL is widely used nowadays for specifying and executing composite business processes within the Service Oriented Architecture (SOA). During the execution however, of such business processes, a number of faults stemming from the nature of SOA (e.g. network or server failures) may occur. The WS-BPEL scenario designer must therefore use the provisions offered by WS-BPEL to catch these exceptions and resolve them, usually by invoking some equivalent web service that is expected to be reachable and available. System fault handler specification is though an additional task for the WS scenario designer, while the presence of such handlers within the scenario necessitates extra maintenance activities, as new alternate services emerge or some of the specified ones are withdrawn. In this paper, we propose a middleware-based framework for system exception resolution, which undertakes the tasks of failure interception, discovery of alternate services and their invocation. The middleware is deployed and maintained independently of the WS-BPEL scenarios, removing thus the need for specifying and maintaining system fault handlers within the scenarios. We also present performance measures, establishing that the overhead imposed by the addition of the proposed middleware layer is minimal. Β{\textcopyright} 2008 ACM.},
	keywords = {Ad hoc networks, Business Process, Exception handling, Information retrieval, Information services, Maintenance activity, Middleware, Middleware layer, Performance evaluation, Performance measure, Performance metrics, Quality control, Quality of service, Quality of service (QoS), Scalability, Service oriented architecture (SOA), System faults, Telecommunication services, Web services, WS-BPEL},
	doi = {10.1145/1497308.1497355},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70349146138\&partnerID=40\&md5=9a5231fe52fffef11707efd4f3489a37},
	author = {Christos Kareliotis and Costas Vassilakis and S. Rouvas and P. Georgiadis}
}
@conference {DBLP:conf/icws/KareliotisVG07,
	title = {Enhancing BPEL scenarios with Dynamic Relevance-Based Exception Handling},
	booktitle = {ICWS},
	year = {2007},
	month = {7},
	pages = {751-758},
	abstract = {Web services have become the key technology in business processes management. Business processes can be self-contained or be composed from sub-processes; the latter category is typically specified using the Web Services Business Process Execution Language (WS-BPEL) and executed by a Web Services Orchestrator (WSO). During the execution however of such a composite service, a number of faults stemming from the distributed nature of the SOA architecture, e.g. network or server failures may occur. WS-BPEL includes provisions for exception handling, which can be exploited for detecting such failures; once detected, a failure can be resolved by invoking alternate web service implementations that perform the same business task as the failed one. However, the inclusion of such provisions is a tedious assignment for the business process designer, while additional effort would be required to maintain the BPEL scenarios in cases that some alternate WS implementations cease to exist or new ones are introduced. In our research we are developing a framework for automating handling of that kind of exceptions. The proposed solution employs a pre-processor that enhances BPEL scenarios with code that detects failures, discovers alternate WS implementations and invokes them, fully thus resolving the exception. Alternate WS implementation discovery is based on service relevance, which takes into account both functional and qualitative properties of web services.},
	doi = {10.1109/ICWS.2007.86},
	author = {Christos Kareliotis and Costas Vassilakis and P. Georgiadis}
}
@conference {kareliotis2006,
	title = {Towards Dynamic, Relevance-Driven Exception Resolution in Composite Web Services},
	booktitle = {Proceedings of OOPSLA 2006, Fourth International Workshop on SOA \& Web Services Best Practices},
	year = {2006},
	month = {10},
	abstract = {Web services have become the leading technology for application-toapplication (A2A) communication over distributed and heterogeneous environments. Both academia and industry have strived to enable useful service collaborations among distributed systems without any human intervention. Web service composition can be used to this end, to achieve business automation within one company or realize business-to-business (B2B) integration of heterogeneous software and cross-organizational computing systems. Service composition pro-vides added value, when a web service composition itself becomes a higher level composite web service. However, as business processes are long-lasting transactions, exceptions may often occur, necessitating the replacement of a service component which has been made unavailable, hindering the completion of some business process. In this paper we present an exception resolving approach based on discovering replacement components that are functionally equivalent, taking also into account criteria for qualitative substitutability. The proposed solution introduces the Service Relevance and Replacement Framework (SRRF) which undertakes exception handling.},
	author = {Christos Kareliotis and Costas Vassilakis and P. Georgiadis}
}
