Developing agent Web service agreements

Web services have emerged as a new paradigm that supports loosely-coupled distributed systems in service discovery and service execution. Next generation Web services evolve from performing static invocations to engaging in flexible interactions and negotiations for dynamic resource procurement. To this end, this paper applies an agent-oriented based approach over a Web service language, WS-Agreement, in order to facilitate conversations of sufficient expressiveness between adaptive and autonomous services. We discuss how such agent Web service agreements can be implemented over IBM's emerging technologies toolkit (ETTK) that itself includes an implementation of the WS-Agreement specification

Implementation of ontology for intelligent hospital ward

We have developed and implemented an ontology for an intelligent hospital ward. Our aim is to address the pervasiveness of computing applications in healthcare environments, which require: sharing of data across the hospital, including data generated by sensors and embedded in such environments, and dealing with semantic heterogeneity that exists across the hospital's data repositories. Our conceptual ontological model that supports such an environment has been implemented using semantic web tools and tested through the application developed with the J2EE technology

Towards service-oriented ontology-based coordination

Coordination is a central problem in distributed computing. The aim is towards flexible coordination, managed at run-time, in open, dynamic environments. This approach would benefit from an explicit common vocabulary for coordination and hence, in a previous paper, we modelled coordination in an ontology, describing the activities carried out and the interdependencies among these activities. The purpose of this paper is to show how such an ontology can be used alongside a set of rules to perform coordination by managing the interdependencies among activities. The ontology and rules can then be used to provide a general purpose coordination tool in the form of a Web servic

Using Electronic Institutions to secure Grid environments

Abstract. As the technical infrastructure to support Grid environments matures, attention must be focused on integrating such technical infrastructure with technologies to support more dynamic access to services, and ensuring that such access is appropriately monitored and secured. Such capabilities will be key in providing a safe environment that allow the creation of virtual organisations at run time. This paper addresses this issue by analysing how work from within the field of Electronic Institutions (EIs) can be employed to provide security support for Grid environments, and introduces the notion of a Semantic Firewall (SFW) responsible for mediating interactions with protected services given a set of access policies. An overarching guideline is that such integration should be pragmatic, taking into account the real-life lessons learned whilst developing, deploying and using the GRIA infrastructure for Grid environments

Developing Agent Web Service Agreements

Web services have emerged as a new paradigm that supports loosely-coupled distributed systems in service discovery and servce execution. Next generation web services will evolve from performing static invocations to engaging in flexible interactions and negotiations for dynamic resource procurement. To this end, this paper applies an agent-oriented based approach over a recent web service language, WS-Agreement, in order to facilitate conversations of sufficient expressiveness between adaptive and autonomous services. We discuss how such agent web service agreements can be implemented over IBM's Emerging Technologies Toolkit (ETTK) that itself includes an implementation of the WS-Agreement specification

Protocol engineering for web services conversations

Although web services aim to bring about seamless and effective communication in a wide variety of Internet applications, the interactions between them are currently limited to simple request-response exchanges. However, in the longer term we believe this is unsustainable. In particular, we believe that more complex protocols for web service conversations are necessary if the participants are to tailor their needs and offers to the prevailing context and they are to coordinate multiple services in open and realistic environments. To this end, this paper combines and extends two recent web service languages, WS-Conversation Language (WSCL) and WS-Agreement, in order to obtain a method for engineering protocols of sufficient expressiveness for the next generation of flexible and autonomous services. Specifically, we propose that the protocols include speech-acts as the individual messages and we show how to model such speech-acts as WS-Agreement schemas, which can, in turn, be imported into the specification of the protocols in WSCL. To demonstrate our approach we express a standard contracting protocol in the extended WSCL/WS-Agreement languages. Furthermore, we use statechart notation as a visual counterpart to help developers write clients that flexibly interact with a service and to help users to better understand how to interact with a service. Finally, we show that the translation between statecharts and WSCL/WS-Agreement protocols is straightforward

Negotiation for authorisation in virtual organisation

In virtual organisations, the authorisation and expression of policies in terms of direct trust relationships between providers and consumers have the problems of scalability, flexibility, expressibility, and lack of policy hierarchy because of interdependent institutions and policies [Pearlman et al. 2003]. This paper proposes a bilateral negotiation protocol and an English auction to negotiate a list of credentials to be exchanged after a service level agreement has been drafted, and that would provide sufficient trustworthiness for the parties in the negotiation. We implement and evaluate our algorithms as grid services in a virtual organisation (VO) to show the effect of negotiation on the trustworthiness achieved within a VO

Ensuring consistency on the joint beliefs of interacting agents

Agent interaction in realistic applications is subject to many forms of uncertainty - including information and network uncertainty, trust of and conflicts with other participants, lack of stability in a deal and risks about agreements and commitments. However, one of the most common forms of uncertainty occurs when a group has divergent beliefs about the interaction they are engaged in - some agents believe an agreement has been reached, while others believe it has been rejected or that they are still bargaining. Such misunderstandings can arise because of loss of network performance, spurious connections, message loss or delays. Against this background, this paper develops synchronisation protocols for a group of agents to attain the same beliefs about an interaction, independent of the reliability of the underlying communication layer. This paper includes and proves theorems about a groups mutual beliefs, on which the safety of an interaction relies. Specifically, protocols for message exchange and belief revision and the reasoning for reachability of states during interactions are presented. Each protocol is proved to show that an increasing level of mutual and consistent belief is reached, thereby guaranteeing an interactions integrity

Developing agent interaction protocols graphically and logically

Although interaction protocols are often part of multi-agent infrastructures, many of the published protocols are semi-formal, vague or contain errors. Formal presentations can counter such disadvantages since they are amenable to verification of correctness. On the other hand, a diagrammatic representation of system structure is easier to comprehend. To this end, this paper bridges the gap between formal specification and intuitive development by: (1) proposing an extended form of propositional dynamic logic for expressing protocols completely, with clear semantics, that can be converted to a programming language for interaction protocols and (2) developing extended statecharts as a diagrammatic counterpart