ARTICLE IN PRESS The Journal of Logic and Algebraic Programming xx (2006) xxx–xxx

www.elsevier.com/locate/jlap Reasoning about interaction protocols for customizing web service selection and composition

Reasoning about interaction protocols for customizing web service selection and composition

AbstractThis work faces the problem of automatic selection and composition of web services, discussing the advantages that derive from the inclusion, in a web service declarative description, of the high-level communication protocol, that is used by the service for interacting with its partners, allowing a rational inspection of it. The approach we propose is set in the Semantic Web field of research and inherits from research in the field of multi-agent systems. Web services are viewed as software agents, communicating by predefined sharable interaction protocols. A logic programming framework based on modal logic is proposed, where the protocol-based interactions of web services are formalized and the use of reasoning about actions and change techniques (planning) for performing the tasks of selection and composition of web services in a way that is personalized w.r.t. the user request is enabled. We claim that applying reasoning techniques on a declarative specification of the service interactions allows to gain flexibility in fulfilling the user preference in the context of a web service matchmaking process

Web service composition : architecture, frameworks, and techniques

OASIS defines Service Oriented Architecture (SOA) as a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. One approach to realize SOA is Web services. A Web service is a software system that has a machine processable Web Services Description Language (WSDL) interface; other systems interact with it using SOAP messages in a manner prescribed by its description. Descriptions enable Web services to be discovered, used by other Web services, and composed into new Web services. Composition is a mechanism for rapid creation of new Web services by reusing existing ones. Web services have functional, behavioral, semantic, and non-functional characteristics. These characteristics have to be considered for composition, as they provide essential information about the services. In order to compose Web services with these characteristics, they have to be described appropriately. However, the existing techniques do not consider all these aspects together for description and composition. This thesis proposes a business model, also referred to as architecture, a description framework, and a composition framework for Web service composition. Techniques for matching, categorizing, and assembling the composite services are also proposed as a part of the composition framework. The architecture, frameworks, and techniques describe, discover, manipulate, and compose Web services by taking into account all their characteristics. The standard Web service business model is extended by the proposed business model to support Web service composition. In the model, based on their demand, the requested Web services are composed by the Web service composer. In the proposed architecture, Web services are described using the description framework languages. The proposed framework combines Semantic Annotations for WSDL and XML Schema (SAWSDL) for functional and semantic description, Message Sequence Charts (MSC) for behavioral description, and a simple and new Non Functional Specification Language (NFSL) for the non-functional properties description of Web services. It uses Higher Order Logic (HOL) for formalizing and integrating the three languages. The role of Web service composer in the architecture is realized by the composition framework. It essentially defines the architecture of the composer. In this framework, matchmaking, categorization, and assembly techniques are used to create the requested composite service. These techniques manipulate the Web services at HOL-level. The formal matchmaking technique discovers the primitive Web services by using a HOL theorem prover. The categorization and the assembly techniques manipulate the matched services and orchestrate the composite service. The concepts of the model, frameworks, and techniques are implemented, and their working is illustrated using case studies. Prototypes of the model's components (extended registry and extended requester) and the composition framework are developed, and their performance is analyzed. Case studies to illustrate the description and the composition frameworks are also presente

Regulating competence-based access to agent societies

Advances in ubiquitous computing have resulted in changes to the way we access and use everyday applications, e.g. reading mail and booking tickets. At the same time, users interact with these applications in a variety of ways, each with different characteristics, e.g., different degrees of bandwidth, different payment schemes supported and so on. These are highly dynamic interactions, as some of the applications might become unavailable (either temporarily or permanently) or their behaviour may change. As the user has to deal with a large number of proactive and dynamic applications every day, he will need a personal assistant that possesses similar characteristics. The agent paradigm meets this requirement, since it exhibits the necessary features. As a result, the user will provide its personal agent assistant with a goal, e.g. I need a smartphone which costs less than three hundred pounds, and the agent will have to use a number of applications offering information on smartphones so that it finds the requested one. This, in turn, raises a number of issues regarding the organisation and the degrees of access to these services as well as the correctness of their descriptions. In this work, we propose the organisation of applications around the concept of artificial agent societies, to which access would be possible only by a positive evaluation of an agent's application. The agent will provide the Authority Agent with the role it is applying for and its competencies in the context of a protocol, i.e., the messages that it can utter/understand. The Authority Agent will then check to see if the applicant agent is a competent user of the protocols; if yes, entry is granted. Assuming that access is granted, the next issue is to decide on the protocol(s) that agent receives. As providing the full protocol will cause security and overload problems, we only need to provide the part required for the agent to play its role. We show how this can be done and how we can repair certain protocols so that they are indeed enactable once this role decomposition is performed

Regulating competence-based access to agent societies

Advances in ubiquitous computing have resulted in changes to the way we access and use everyday applications, e.g. reading mail and booking tickets. At the same time, users interact with these applications in a variety of ways, each with different characteristics, e.g., different degrees of bandwidth, different payment schemes supported and so on. These are highly dynamic interactions, as some of the applications might become unavailable (either temporarily or permanently) or their behaviour may change. As the user has to deal with a large number of proactive and dynamic applications every day, he will need a personal assistant that possesses similar characteristics. The agent paradigm meets this requirement, since it exhibits the necessary features. As a result, the user will provide its personal agent assistant with a goal, e.g. I need a smartphone which costs less than three hundred pounds, and the agent will have to use a number of applications offering information on smartphones so that it finds the requested one. This, in turn, raises a number of issues regarding the organisation and the degrees of access to these services as well as the correctness of their descriptions. In this work, we propose the organisation of applications around the concept of artificial agent societies, to which access would be possible only by a positive evaluation of an agent's application. The agent will provide the Authority Agent with the role it is applying for and its competencies in the context of a protocol, i.e., the messages that it can utter/understand. The Authority Agent will then check to see if the applicant agent is a competent user of the protocols; if yes, entry is granted. Assuming that access is granted, the next issue is to decide on the protocol(s) that agent receives. As providing the full protocol will cause security and overload problems, we only need to provide the part required for the agent to play its role. We show how this can be done and how we can repair certain protocols so that they are indeed enactable once this role decomposition is performed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo