48 results for Cranefield, Stephen, Working or discussion paper

  • 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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  • Contextual information retrieval in research articles: Semantic publishing tools for the research community

    Angrosh, M.A.; Cranefield, Stephen; Stanger, Nigel (2011-07-25)

    Working or discussion paper
    University of Otago

    Over the last few years, the voluminous increase in the academic research publications has gained significant research attention. Research has been carried out exploring novel ways of providing information services using the research content. However, the task of extracting meaningful information from research documents remains a challenge. This paper presents our research work carried out for developing intelligent information systems, exploiting the research content. We present in this paper, a linked data application which uses a new semantic publishing model for providing value added information services for the research community. The paper presents a conceptual framework for modelling contexts associated with sentences in research articles and discusses the Sentence Context Ontology, which is used to convert the information extracted from research documents into machine-understandable data. The paper also reports on supervised learning experiments carried out using conditional probabilistic models for achieving automatic context identification.

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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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  • Energy-aware optimisation of business processes

    Lopez, Beatriz; Ghose, Aditya; Savarimuthu, Bastin Tony Roy; Nowostawski, Mariusz; Winikoff, Michael; Cranefield, Stephen (2012-04-13)

    Working or discussion paper
    University of Otago

    Due to changes in energy supply, and regulatory mechanism related to energy provisioning, organizations will need to tackle energy management is- sues. One way of doing so is to allocate resources to business processes taking into account energy costs. However, energy costs are time-dependent, and the re- source optimization problem needs to be redesigned. In this paper we formalize the energy-aware resource allocation problem, including time-dependent variable costs; describe how an auction mechanism can be used to allocate resources in a way that optimizes costs; and present a case study.

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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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  • Extending agent messaging to enable OO information exchange

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

    Working or discussion paper
    University of Otago

    It is canonical practice in agent-based systems to use a declarative format for the exchange of information. The increasing usage and facility of object-oriented tools and techniques, however, suggests there may be benefits in combining the use of object-oriented modelling approaches with agent-based messaging. In this paper we outline our efforts in connection with the New Zealand Distributed Information Systems project to use object-oriented knowledge representation in an agent-based architecture. Issues and tradeoffs are discussed, as well as the possible extensions to current agent-based message protocols that may be necessary in order to support object-oriented information exchange.

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  • Interaction protocols for a network of environmental problem solvers

    Purvis, Martin; Hwang, Peter; Cranefield, Stephen; Schievink, Martin; Purvis, Maryam A. (2002-04)

    Working or discussion paper
    University of Otago

    Environmental management and emergency response often involves the joint cooperation of a network of distributed problem solvers, each of which may be specialised for a specific task or problem domain. Some of these problem solvers could be human, others could be `intelligent' environmental monitoring and control systems. Environmental software systems are needed not only for the provision of basic environmental information but also to support the coordination of these problem solvers. An agent architecture can support the requirement associated with disparate problem solvers. The various stakeholders in the process are represented by software agents which can collaborate with each other toward achieving a particular goal. The communication between agents can be accomplished by using interaction protocols which are represented by coloured Petri nets (CPN). This paper describes an approach for providing this support by employing a software agent framework for the modelling and execution of environmental process tasks in a networked environment.

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  • Planning and matchmaking in a multi-agent system for software integration

    Diaz, Aurora; Cranefield, Stephen; Purvis, Martin (1997-06)

    Working or discussion paper
    University of Otago

    Computer users employ a collection of software tools to support their day-to-day work. Often the software environment is dynamic with new tools being added as they become available and removed as they become obsolete or outdated. In today’s systems, the burden of coordinating the use of these disparate tools, remembering the correct sequence of commands, and incorporating new and modified programs into the daily work pattern lies with the user. This paper describes a multi-agent system, DALEKS, that assists users in utilizing diverse software tools for their everyday work. It manages work and information flow by providing a coordination layer that selects the appropriate tool(s) to use for each of the user’s tasks and automates the flow of information between them. This enables the user to be concerned more with what has to be done, rather than with the specifics of how to access tools and information. Here we describe the system architecture of DALEKS and illustrate it with an example in university course administration.

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  • Interfacing a cognitive agent platform with Second Life

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

    Working or discussion paper
    University of Otago

    Second Life is a multi-purpose online virtual world that provides a rich platform for remote human interaction. It is increasingly being used as a simulation platform to model complex human interactions in diverse areas, as well as to simulate multi-agent systems. It would therefore be beneficial to provide techniques allowing high-level agent development tools, especially cognitive agent platforms such as belief-desire-intention (BDI) programming frameworks, to be interfaced to Second Life. This is not a trivial task as it involves mapping potentially unreliable sensor readings from complex Second Life simulations to a domain-specific abstract logical model of observed properties and/or events. This paper investigates this problem in the context of agent interactions in a multi-agent system simulated in Second Life. We present a framework which facilitates the connection of any multi-agent platform with Second Life, and demonstrate it in conjunction with an extension of the Jason BDI interpreter.

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  • Monitoring social expectations in Second Life

    Cranefield, Stephen; Li, Guannan (2009-05)

    Working or discussion paper
    University of Otago

    Online virtual worlds such as Second Life provide a rich medium for unstructured human interaction in a shared simulated 3D environment. However, many human interactions take place in a structured social context where participants play particular roles and are subject to expectations governing their behaviour, and current virtual worlds do not provide any support for this type of interaction. There is therefore an opportunity to adapt the tools developed in the MAS community for structured social interactions between software agents (inspired by human society) and adapt these for use with the computer-mediated human communication provided by virtual worlds. This paper describes the application of one such tool for use with Second Life. A model checker for online monitoring of social expectations defined in temporal logic has been integrated with Second Life, allowing users to be notified when their expectations of others have been fulfilled or violated. Avatar actions in the virtual world are detected by a script, encoded as propositions and sent to the model checker, along with the social expectation rules to be monitored. Notifications of expectation fulfilment and violation are returned to the script to be displayed to the user. This utility of this tool is reliant on the ability of the Linden scripting language (LSL) to detect events of significance in the application domain, and a discussion is presented on how a range of monitored structured social scenarios could be realised despite the limitations of LSL.

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  • An agent-based architecture for software tool coordination

    Cranefield, Stephen; Purvis, Martin (1996-12)

    Working or discussion paper
    University of Otago

    This paper presents a practical multi-agent architecture for assisting users to coordinate the use of both special and general purpose software tools for performing tasks in a given problem domain. The architecture is open and extensible being based on the techniques of agent-based software interoperability (ABSI), where each tool is encapsulated by a KQML-speaking agent. The work reported here adds additional facilities for the user to describe the problem domain, the tasks that are commonly performed in that domain and the ways in which various software tools are commonly used by the user. Together, these features provide the computer with a degree of autonomy in the user's problem domain in order to help the user achieve tasks through the coordinated use of disparate software tools. This research focuses on the representational and planning capabilities required to extend the existing benefits of the ABSI architecture to include domain-level problem-solving skills. In particular, the paper proposes a number of standard ontologies that are required for this type of problem, and discusses a number of issues related to planning the coordinated use of agent-encapsulated tools.

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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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  • Verifying social expectations by model checking truncated paths

    Cranefield, Stephen; Winikoff, Michael (2007-12)

    Working or discussion paper
    University of Otago

    One approach to moderating the behaviour of agents in open societies is the use of explicit languages for defining norms, conditional commitments and/or social expectations, together with infrastructure supporting conformance checking and the identification and possible punishment of anti-social agents. This paper presents a logical account of the creation, fulfilment and violation of social expectations modelled as conditional rules over a hybrid propositional temporal logic. The semantics are designed to allow model checking over finite histories to be used to check for fulfilment and violation of expectations in both online and offline modes. For online checking, expectations are always considered at the last state in the history, but in the offline mode expectations in previous states are also checked. At each past state, the then active expectations must be checked for fulfilment without recourse to information from later states: the truth of a future-oriented temporal proposition φ at state s over the full history does not imply the fulfilment at s of an expectation with content φ. This issue is addressed by defining fulfilment and violation in terms of an extension of Eisner et al.’s weak/strong semantics for LTL over truncated paths. The update of expectations from one state to the next is based on formula progression and the approach has been implemented by extending the MCLITE and MCFULL algorithms of the Hybrid Logic Model Checker.

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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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  • How do norms emerge in multi-agent societies? Mechanisms design

    Savarimuthu, Bastin Tony Roy; Cranefield, Stephen; Purvis, Martin; Purvis, Maryam A. (2007-02)

    Working or discussion paper
    University of Otago

    Norms are shared expectations of behaviours that exist in human societies. Norms help societies by increasing the predictability of individual behaviours and by improving co-operation and collaboration among members. Norms have been of interest to multi-agent system researchers as software agents intend to follow certain norms. But, owing to their autonomy, agents sometimes violate norms which needs monitoring. There are two main branches of research in normative agent systems. One of the branches focuses on normative agent architectures, norm representations, norm adherence and the associated punitive or incentive measures. The other branch focuses on two main issues. The first issue is on the study of spreading and internalization of norms. The second issue that has not received much attention is the emergence of norms in agent societies. Our objective in this paper is to propose mechanisms for norm emergence in artificial agent societies and provide initial experimental results.

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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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  • 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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  • Multi-agent system interaction protocols in a dynamically changing environment

    Purvis, Martin; Cranefield, Stephen; Nowostawski, Mariusz; Purvis, Maryam A. (2002-07)

    Working or discussion paper
    University of Otago

    An area where multi-agent systems can be put to effective use is for the case of an open collection of autonomous problem solvers in a dynamically changing environment. One example of such a situation is that of environmental management and emergency response, which can require the joint cooperation of a distributed set of components, each one of which may be specialised for a specific task or problem domain. The various stakeholders in the process can all be represented and interfaced by software agents which collaborate with each other toward achieving a particular goal. For such situations new agents that arrive on the scene must be apprised of the group interaction protocols so that they can cooperate effectively with the existing agents. In this paper we show how this can be done by using coloured Petri net representations for each role in an interaction protocol and passing these nets dynamically to new agents that wish to participate in a group interaction. We argue that multi-agent systems are particularly suited for such dynamically changing environments, but their effectiveness depends on the their ability to use adaptive interaction protocols.

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  • Planning and matchmaking for the interoperation of information processing agents

    Cranefield, Stephen; Diaz, Aurora; Purvis, Martin (1997-02)

    Working or discussion paper
    University of Otago

    In today's open, distributed environments, there is an increasing need for systems to assist the interoperation of tools and information resources. This paper describes a multi-agent system, DALEKS, that supports such activities for the information processing domain. With this system, information processing tasks are accomplished by the use of an agent architecture incorporating task planning and information agent matchmaking components. We discuss the characteristics of planning in this domain and describe how information processing tools are specified for the planner. We also describe the manner in which planning, agent matchmaking, and information task execution are interleaved in the DALEKS system. An example application taken from the domain of university course administration is provided to illustrate some of the activities performed in this system.

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