Shamimabi Paurobally

A Framework for Web service negotiation

In a survey on the theory and practice of agent system deployment, conducted by the AgentLink workgroup on networked agents, it was found that there are an increasing number of initiatives for the migration of agents research towards new Internet technologies such as the semantic web, Grid, and Web services. In fact, Grid computing and multi-agent systems research have similar objectives. They both aim to achieve “large-scale open distributed systems, capable of being able to effectively and dynamically deploy and redeploy computational (and other) resources as required, to solve computationally complex problems” [Foster and Kesselman 2003]. On the one hand, service-oriented Grid architectures need to support dynamic cooperation, negotiation, and adaptive interactions between Web services controlling Grid resources for efficient resource and task allocation and execution. On the other hand, the Grid can facilitate agent communication, life-cycle management, and access to resources for agents. Although the relevance of Grid for agent research and vice versa has been identified in several forums, actual collaborative applications are still in their infancy. In this article, we discuss our recent work on deploying multi-agent negotiation techniques to facilitate dynamic negotiation for Grid resources as a step closer to an adaptive and autonomous Grid. In particular, we describe a Web service development of the Contract Net Protocol for negotiation between insurance companies and repair companies. We evaluate our approach to show the added value of negotiable interactions between Web services as opposed to inflexible single-shot interactions that are currently the state of the art.

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.

Developing Agent Interaction Protocols Using Graphical and Logical Methodologies

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.

Automating negotiation for m-services

Mobile electronic commerce (m-commerce) is an emerging manifestation of Internet electronic commerce that bridges the domains of Internet, mobile computing and wireless telecommunications in order to provide an array of sophisticated services (m-services) to mobile users. To date, much of the research in the area has concentrated on the problem of service discovery. However, once a service has been discovered, it needs to be provisioned according to the goals and constraints of the service provider and the service consumer. Since, in general, these will be different stakeholders (with different aims), the de facto provisioning method will be some form of negotiation. To this end, this paper develops automated negotiation protocols and strategies that are applicable in m-commerce environments. Specifically, we develop and evaluate time-constrained bilateral negotiation algorithms, that allow software agents to adapt to the quality of the network and/or their experience of similar interactions.

Implementation of Ontology for Intelligent Hospital Wards

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 hospitals 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.

Ensuring consistency in 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.

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 service

A formal framework for agent interaction semantics

Although informative, the semantic definition proposed for the most standard agent communication language (FIPA ACL 1997) is complicated and contentious, while published interaction protocols (IPs) tend to be ambiguous, incomplete, and unverified with respect to message semantics. To clarify and help rectify these problems, this paper proposes an integrated framework based on Propositional Dynamic Logic and Belief and Intention modalities (called the PDL-BI language). Specifically, we provide an axiomatisation of PDL-BI and for an agents propositional attitudes (beliefs and intentions) and social attitudes (such as sincerity and trustworthiness). Then we suggest a revised and simpler core semantics for many of the FIPA ACL speech acts, which, in turn, lead to the specification of the semantics of IPs. As a case study, we specify the semantics of the contract net protocol (CNP) in PDL-BI, which allows to prove that the CNP terminates.

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 IBMs emerging technologies toolkit (ETTK) that itself includes an implementation of the WS-Agreement specification.

Web services negotiation in an insurance grid

There are an increasing number of initiatives for the migration of agents research towards new Internet technologies such as the semantic web, Grid, and web services. On the one hand, service oriented Grid architectures need to support dynamic cooperation, negotiation and coordination between web services controlling Grid resources, for efficient resource and task allocation and execution. On the other hand, the Grid can facilitate agent communication, life-cycle management, and access to resources for agents. The insurance sector is one such area that would benefit from the automation brought by multi-agent systems techniques in handling claims and detecting fraudulent cases. In this paper, we discuss our work on facilitating dynamic and adaptive negotiation between web and grid services. We describe our deployed approach in an InsuranceGrid, which manages businesses involved in dealing with car damage claims for a number of insurance companies.