Computing is moving toward a pervasive context-aware environment in which agents with limited resources will require external support to help them become context-aware. In this paper, we describe an agent based architecture called Context Broker Architecture (CoBrA) to help these agents to acquire, reason about and share context knowledge. A key component in our architecture is an explicit context ontology defined using the Web Ontology Language (OWL). This ontology models the basic concepts of people, agents, places, and presentation events. We also describe a use case scenario and prototype design of CoBrA in an intelligent meeting room environment.
growing use of agent systems and the widespread pen- etration of the Internet has opened up new possibilities for scientific collaboration. We have been investigating the role for agent systems to aid with collaboration among Exper- imental High-Energy Physics (EHEP) physicists. A neces- sary component is an agreed ontology, which must include complex mathematical relations involving such quantities as the energy and momentum of elementary physics particles. We claim that the current web-ontology specification lan- guages are not suciently expressive to be useful for explicit representation of mathematical expressions. We adapt some previous work on representing mathematical expressions to produce a set of mathematical representational primitives and supporting definitions that will allow knowledge shar- ing in agent systems. The paper sketches out a scheme for dealing with mathematical relations in scientific domain web-ontologies, illustrated with examples arising from our interactions with the EHEP physicists.
This paper presents our practical experience of developing an ontology using the EXPLODE method for Value-Added Publishing. Value-Added Publishing is a relatively new area of electronic information distribution that extends beyond the established simple modes of online publishing. VAP considers the needs of the user as a primary measure of effectiveness of an online document by evaluating various metrics such as author reputation and number of citations. At implementation level the features of VAP can be achieved by customised information extraction agents. The domain of VAP raises many challenges. VAP is being developed by different groups of researchers, the requirements for the ontology come from many different places, not necessarily consistent with each other. Since VAP is still not a strongly established field, its borders and the issues that it addresses often change. EXPLODE is a method which is suitable for a dynamic environment. In this paper we give an overview of EXPLODE and describe the issues that we encountered and the decisions we had to make regarding the ontology design, structure and content.
This paper illustrates an approach to combining the benefits of a multi-agent system architecture with the use of industry-standard modelling techniques using the Unified Modeling Language (UML). Using a UML profile for ontology modelling, an ontology for travel booking services is presented and the automatic derivation of an object-oriented content language for this domain is described. This content language is then used to encode example messages for a simple travel booking scenario, and it is shown how this approach to agent messaging allows messages to be created and analysed using a convenient object-oriented application-specific application programmer interface.
Current Web services standards enable publishing service descriptions and finding services by matching requested and published descriptions based on syntactic criteria such as method signatures or service category. Emerging approaches such as DAML-S use DAML to formalize richer models for expressing capabilities of services. DAML-S would go beyond WSDL in terms of the richness of service descriptions. However, neither current Web services standards nor DAML-S provide a basis for selecting a good service or for comparing services that implement the same interface. In our view, service selection is the key problem to enable applicationto-application integration, which is the essential vision behind Web services. Existing approaches don’t address service selection, because service selection inherently involves trust and must consider criteria that are external to any published description of a service, whether in WSDL or DAML-S. Accordingly, this paper develops an ontology in which ratings of services (aggregated into reputations) can be organized and shared so as to facilitate service selection. This model is expressed in DAML and includes domainindependent as well as domain-specific attributes.
We present our initial response to the OAS '03 Challenge Problem. The Challenge Problem proposes an agent-assisted travel scenario, and asks what the role of ontologies would be to support the agent's activity. We discuss a belief-desire-intention (BDI) approach to the problem using our Nuin agent platform, and illustrate various ways in which ontology reasoning supports BDI-oriented problem solving and communications by the agents in the system.
This chapter describes a set of experiments that uses a multiagent framework for collaborative understanding of distributed ontologies (CUDO). Our current focus is on the operational issues of such collaboration among the agents, with each agent managing an information database in a distributed information retrieval simulation. To facilitate collaborative understanding, each agent maintains an ontology and a translation table with other neighboring agents to map between each own concepts and the neighbors'. Based on an infrastructure prototype, our experiments have focused on how neighborhood profiling, the translation tables, and query experience impact the collaborative activities among the agents. The specific objectives of our analyses are to investigate (a) the recognition of useful neighbors for sharing queries, (b) the efficiency of query handling in different real-time scenarios and with different resource constraints (such as the number of threads and available translations), and (c) the effects of different concepts and query demands on collaborative understanding. Our results show that the different resource constraints influence the collaborative activities significantly and thus also impact how the agents learn of each others ontologies.
The growing interest in ontologies is concomitant with the increasing use of agent systems in user environment. Ontologies have established themselves as schemas for encoding knowledge about a particular domain, which can be interpreted by both humans and agents to accomplish a task in cooperation. However, construction of the domain ontologies is a bottleneck, and planning towards reuse of domain ontologies is essential. Current methodologies concerned with ontology development have not dealt with explicit reuse of domain ontologies. This paper presents guidelines for systematic construction of reusable domain ontologies. A purpose-driven approach has been adopted. The guidelines have been used for constructing ontologies in the Experimental High-Energy Physics domain.
A fundamental issue of human-centered coordinating services in ubiquitous computing is concerned with dynamic service coordination according to users' intentions. How can we coordinate the services to assist the user in receiving a coordinated service to maximize the user's satisfaction in an environment? In order to solve this issue, we have been developing a sort of agent-based coordination framework, called "location-mediated agent coordination," that orchestrates Web services embedded in the real world and Web services on the Internet. In this paper, we show a prototype application of the framework, context-aware information assist services in a museum.
There is a large gap between the emerging theory of institutions, or to be more accurate the norms that characterize them, how agents might reason about a symbolic representation of those norms and software tools to realize agent-trading platforms from high level specifications. We present an initial representation for institutions written in XML and their ontologies written in DAML+OIL and show how it has been used to specify aspects of simple auction house (the FishMarket [12]) from which we are able to generate automatically the components of the performative structure and the agent skeletons for an implementation on top of the JADE platform.
