48 results for Cranefield, Stephen, Working or discussion paper

  • Implementing agent communication languages directly from UML specifications

    Cranefield, Stephen; Purvis, Martin; Nowostawski, Mariusz (2001-02)

    Working or discussion paper
    University of Otago

    This paper proposes the use of the Unified Modelling Language (UML) as a formalism for defining an abstract syntax for Agent Communication Languages (ACLs) and their associated content languages. It describes an approach supporting an automatic mapping from high-level abstract specifications of language structures to specific computer language bindings that can be directly used by an agent platform. Some advantages of this approach are that it provides a framework for specifying and experimenting with alternative agent communication languages and reduces the error-prone manual process of generating compatible bindings and grammars for different syntaxes. A prototype implementation supporting an automatic conversion from an abstract communication language expressed in UML to a native Java API and a Resource Description Framework (RDF) serialisation format is described.

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  • Integrating expectation handling into Jason

    Ranathunga, Surangika; Cranefield, Stephen; Purvis, Martin (2011-02)

    Working or discussion paper
    University of Otago

    Although expectations play an important role in designing cognitive agents, agent expectations are not explicitly being handled in most common agent programming environments. There are techniques for monitoring fulfilment and violation of agent expectations, however they are not linked with common agent programming environments so that agents can be easily programmed to respond to these circumstances. This paper investigates how expectation monitoring tools can be tightly integrated with the Jason BDI agent interpreter by extending it with built-in actions to initiate and terminate monitoring of expectations, and demonstrates how an external expectation monitor is linked with Jason using these internal actions.

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  • A rule language for modelling and monitoring social expectations in multi-agent systems

    Cranefield, Stephen (2005-02)

    Working or discussion paper
    University of Otago

    This paper proposes a rule language for defining social expectations based on a metric interval temporal logic with past and future modalities and a current time binding operator. An algorithm for run-time monitoring compliance of rules in this language based on formula progression is also presented.

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  • On the testability of BDI agent systems

    Winikoff, Michael; Cranefield, Stephen (2008-11)

    Working or discussion paper
    University of Otago

    Before deploying a software system we need to assure ourselves (and stake-holders) that the system will behave correctly. This assurance is usually done by testing the system. However, it is intuitively obvious that adaptive systems, including agent-based systems, can exhibit complex behaviour, and are thus harder to test. In this paper we examine this “obvious intuition” in the case of Belief-Desire-Intention (BDI) agents. We analyse the size of the behaviour space of BDI agents and show that although the intuition is correct, the factors that influence the size are not what we expected them to be; specifically, we found that the introduction of failure handling had a much larger effect on the size of the behaviour space than we expected. We also discuss the implications of these findings on the testability of BDI agents.

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  • Generating ontology-specific content languages

    Cranefield, Stephen; Purvis, Martin (2001-05)

    Working or discussion paper
    University of Otago

    This paper examines a recent trend amongst software agent application and platform developers to desire the ability to send domain-specific objects within inter-agent messages. If this feature is to be supported without departing from the notion that agents communicate in terms of knowledge, it is important that the meaning of such objects be well understood. Using an object-oriented metamodelling approach, the relationships between ontologies and agent communication and content languages in FIPA-style agent systems are examined. It is shown how object structures in messages can be considered as expressions in ontology-specific extensions of standard content languages. It is also argued that ontologies must distingish between objects with and objects without identity.

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  • Automating information processing tasks: an agent-based architecture

    Cranefield, Stephen; McKinlay, Bryce; Moreale, Emanuela; Purvis, Martin (1998-03)

    Working or discussion paper
    University of Otago

    This paper describes an agent-based architecture designed to provide automation support for users who perform information processing tasks using a collection of distributed and disparate software tools and on-line resources. The architecture extends previous work on agent-based software interoperability. The unique features of the information processing domain compared to distributed information retrieval are discussed and a novel extension of hierarchical task network (HTN) planning to support this domain is presented.

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  • Communicating agents: an emerging approach for distributed heterogeneous systems

    Cranefield, Stephen; Gorman, Paul; Purvis, Martin (1995-07)

    Working or discussion paper
    University of Otago

    The concept of an intelligent software agent has emerged from its origins in artificial intelligence laboratories to become an important basis for the development of distributed systems in the mainstream computer science community. This paper provides a review of some of the ideas behind the intelligent agent approach and addresses the question “what is an agent?” Some principal application areas for agent-based computing are outlined and related research programmes at the University of Otago are discussed.

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  • Extracting data from Second Life

    Ranathunga, Surangika; Cranefield, Stephen; Purvis, Martin (2011-07-29)

    Working or discussion paper
    University of Otago

    Second Life is a multi-purpose online virtual world that is increasingly being used for applications and simulations in diversified areas such as education, training, entertainment, and even for applications related to Artificial Intelligence. For the successful implementation and analysis of most of these applications, it is important to have a robust mechanism to extract low-level data from Second Life in high frequency and high accuracy. However, currently Second Life does not have a reliable or scalable inbuilt data extraction mechanism, nor the related research provides a better alternative. This paper presents a robust and reliable data extraction mechanism from Second Life. We also investigate the currently existing data extraction mechanisms in detail, identifying their limitations in extracting data with high accuracy and high frequency.

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  • A layered approach for modelling agent conversations

    Nowostawski, Mariusz; Purvis, Martin; Cranefield, Stephen (2001-03)

    Working or discussion paper
    University of Otago

    Although the notion of conversations has been discussed for some time as a way in which to provide an abstract representation of extended agent message exchange, there is still no consensus established concerning how to use these abstractions effectively. This paper describes a layered approach based on coloured Petri Nets that can be used for modelling complex, concurrent conversations among agents in a multi-agent system. The approach can be used both to define simple conversation protocols and to define more complex conversation protocols composed of a number of simpler conversations. With this method it is possible (a) to capture the concurrent characteristics of a conversation, (b) to capture the state of a conversation at runtime, and (c) to reuse conversation structures for the processing of multiple concurrent messages. A prototype implementation of such a system with some examples is described.

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  • Agent modelling with Petri nets

    Purvis, Martin; Cranefield, Stephen (1996-03)

    Working or discussion paper
    University of Otago

    The use of intelligent software agents is a modelling paradigm that is gaining increasing attention in the applications of distributed systems. This paper identifies essential characteristics of agents and shows how they can be mapped into a coloured Petri net representation so that the coordination of activities both within agents and between interacting agents can be visualised and analysed. The detailed structure and behaviour of an individual agent in terms of coloured Petri nets is presented, as well as a description of how such agents interact. A key notion is that the essential functional components of an agent are explicitly represented by means of coloured Petri net constructs in this representation.

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  • Integrating environmental information: Incorporating metadata in a distributed information systems architecture

    Cranefield, Stephen; Purvis, Martin (2000-02)

    Working or discussion paper
    University of Otago

    An approach is presented for incorporating metatata constraints into queries to be processed by a distributed environmental information system. The approach, based on a novel metamodel unifying concepts from the Unified Modelling Language (UML), the Object Query Language (OQL), and the Resource Description Framework (RDF), allows metadata information to be represented and processed in combination with regular data queries.

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  • Reliable group communication and institutional actions in a multi-agent trading scenario

    Cranefield, Stephen (2004-12)

    Working or discussion paper
    University of Otago

    The use of asynchronous communication is traditionally seen to be an important element of an agent’s autonomy. This paper argues that groups of agents within a society need the ability to choose forms of communication with stronger guarantees for particular interactions, and in particular, focuses on the use of reliable group communication. An example electronic trading scenario — the game of Pit — is presented, and it is shown how a formal institution for a particular critical phase of Pit can be built on top of the semantics for totally ordered and virtually synchronous multicasting.

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  • Embedding agents in business applications using enterprise integration patterns

    Cranefield, Stephen; Ranathunga, Surangika (2013-02-08)

    Working or discussion paper
    University of Otago

    This paper addresses the issue of integrating agents with a variety of external resources and services, as found in enterprise computing environments. We propose an approach for interfacing agents and existing message routing and mediation engines based on the endpoint concept from the enterprise integration patterns of Hohpe and Woolf. A design for agent endpoints is presented, and an architecture for connecting the Jason agent platform to the Apache Camel enterprise integration framework using this type of endpoint is described. The approach is illustrated by means of a business process use case, and a number of Camel routes are presented. These demonstrate the benefits of interfacing agents to external services via a specialised message routing tool that supports enterprise integration patterns.

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  • UML and the Semantic Web

    Cranefield, Stephen (2001-02)

    Working or discussion paper
    University of Otago

    This paper discusses technology to support the use of UML for representing ontologies and domain knowledge in the Semantic Web. Two mappings have been defined and implemented using XSLT to produce Java classes and an RDF schema from an ontology represented as a UML class diagram and encoded using XMI. A Java application can encode domain knowledge as an object diagram realised as a network of instances of the generated classes. Support is provided for marshalling and unmarshalling this object-oriented knowledge to and from an RDF/XML serialisation.

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  • Communicative acts and interaction protocols in a distributed information system

    Nowostawski, Mariusz; Carter, Dan; Cranefield, Stephen; Purvis, Martin (2003-05)

    Working or discussion paper
    University of Otago

    In FIPA-style multi-agent systems, agents coordinate their activities by sending messages representing particular communicative acts (or performatives). Agent communication languages must strike a balance between simplicity and expressiveness by defining a limited set of communicative act types that fit the communication needs of a wide set of problems. More complex requirements for particular problems must then be handled by defining domain-specific predicates and actions within ontologies. This paper examines the communication needs of a multi-agent distributed information retrieval system and discusses how well these are met by the FIPA ACL.

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  • UML-based ontology modelling for software agents

    Cranefield, Stephen; Haustein, Stefan; Purvis, Martin (2001-05)

    Working or discussion paper
    University of Otago

    Ontologies play an important role in defining the terminology that agents use in the exchange of knowledge-level messages. As object-oriented modelling, and the Unified Modeling Language (UML) in particular, have built up a huge following in the field of software engineering and are widely supported by robust commercial tools, the use of UML for ontology representation in agent systems would help to hasten the uptake of agent-based systems concepts into industry. This paper examines the potential for UML to be used for ontology modelling, compares it to traditional description logic formalisms and discusses some further possibilities for applying UML-based technologies to agent communication systems.

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  • UML as an ontology modelling language

    Cranefield, Stephen; Purvis, Martin (1999-01)

    Working or discussion paper
    University of Otago

    Current tools and techniques for ontology development are based on the traditions of AI knowledge representation research. This research has led to popular formalisms such as KIF and KL-ONE style languages. However, these representations are little known outside AI research laboratories. In contrast, commercial interest has resulted in ideas from the object-oriented programming community maturing into industry standards and powerful tools for object-oriented analysis, design and implementation. These standards and tools have a wide and rapidly growing user community. This paper examines the potential for object-oriented standards to be used for ontology modelling, and in particular presents an ontology representation language based on a subset of the Unified Modeling Language together with its associated Object Constraint Language.

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  • Role model based mechanism for norm emergence in artificial agent societies

    Savarimuthu, Bastin Tony Roy; Cranefield, Stephen; Purvis, Martin; Purvis, Maryam A. (2007-07)

    Working or discussion paper
    University of Otago

    A revised version of this paper appears in the Proceedings of the AAMAS'07 Workshop on Coordination, Organization, Institutions and Norms in Agent Systems (COIN), Honolulu, Hawaii, USA, 14th May, pp. 1-12. See http://www.ia.urjc.es/COIN2007/ for further details.

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  • Causal agent modelling: a unifying paradigm for systems and organisations

    Purvis, Martin; Cranefield, Stephen (1995-07)

    Working or discussion paper
    University of Otago

    With the increasing size, complexity and interconnectedness of systems and organisations, there is a growing need for high level modelling approaches that span the range of application domains. Causal agent modelling offers an intuitive and powerful approach for the development of dynamic models for any application area. This paper outlines some of the basic ideas behind the nature of causal agent models, why they are fundamental to the modelling enterprise, and compares developments in this area to those in the related field of coordination theory. It also describes some research activities using causal agent models at the University of Otago.

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  • Is it an ontology or an abstract syntax? Modelling objects, knowledge and agent messages

    Cranefield, Stephen; Purvis, Martin; Nowostawski, Mariusz (2000-04)

    Working or discussion paper
    University of Otago

    This paper describes a system of interlinked ontologies to describe the concepts underlying FIPA agent communication. A meta-modelling approach is used to relate object-oriented domain ontologies and abstract models of agent communication and content languages and to describe them in a single framework. The modelling language used is the Unified Modeling Language, which is extended by adding the concepts of resource and reference. The resulting framework provides an elegant basis for the development of agent systems that combine object-oriented information representation with agent messaging protocols.

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