Modelling Agent-Environment Interaction in Multi-Agent Simulations with Affordances

298 Pages·2009·6.17 MB·English

Modelling Agent-Environment Interaction in
Multi-Agent Simulations with Affordances
Michael Papasimeon
Submitted in total fulfilment of the requirements of the degree of
Doctor of Philosophy
January 2009
Department of Computer Science and Software Engineering
Melbourne School of Engineering
The University of Melbourne
Victoria 3010
Australia
Produced on archival quality paper
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Abstract
This thesis presents a new computational model of agent – environment in-
teraction that has been inspired by the theory of affordances from ecological
psychology — the theory that humans and animals can directly perceive the
action possibilities of the world around them.
The aim of this work is to provide new approaches to the design of the
interaction mechanism between agents and the environments in which they are
located. Anapproachinspiredbyaffordancetheorycanallowformoresituated,
richer and complex agent behaviours in a virtual environment.
The scope of the work is multi-agent simulation of military operations in
particular air combat operations, where the agents represent cognitive models
of military operators such as fighter pilots. The research is motivated by the
need for humans (for example pilots) and agents (for example simulated pilots
or environmental entities) to interact within a shared virtual environment on an
equal footing.
Theproblemwithcurrentagentprogrammingtechniquestypicallyutilisedis
thattheydonotnecessarilycapturethesalientagent–environmentinteractions.
Existing approaches to developing richer and more complex intelligent agent
behaviours have focused on developing (i) a more intelligent environment or (ii)
a more intelligent agent. This thesis shows an alternative approach, one where
the focus is on the interaction between the agent and the environment that has
the potential for more situated agent behaviour.
Specifically, the interaction is represented using a computational model of
interaction inspired by affordance theory. The model allows for affordances or
action possibilities for each agent to be computed in a manner which allows
for flexibility in the design of the multi-agent simulation. The model captures
the key characteristics of the affordance concept which are relevant to military
multi-agent simulations. These include the intentional and relational nature
iv Abstract
of affordances as well as their ability to be directly perceived by agents in the
environment.
The model is implemented in two complex multi-agent simulations. One
a large scale real world military multi-agent simulation, the other a smaller
implementation of an adversarial game. These implementations allow for the
evaluationofthemodelinaqualitativeandquantitativemanner. Consequently,
the main contributions are:
• An affordance based computational model of agent – environment inter-
action, and
• an analysis of the impact of adopting an affordance based approach to
agent – environment interaction in multi-agent simulations.
The evaluation addresses the impact of an affordance based approach from
a number of different areas. It includes an assessment of the impact on the
designofmulti-agentsimulationswhenanaffordancebasedapproachisadopted.
Specificallyitlooksattwocases,affordancecomputationintheenvironmentand
affordance computation in the agent. The evaluation also looks at the impact
an affordance based approach has on the computational performance of a multi-
agent simulation.
Declaration
This is to certify that
1. the thesis comprises my original work towards the PhD except where in-
dicated in the Preface,
2. dueacknowledgementhasbeenmadeinthetexttoallothermaterialused,
3. the thesis is less than 100,000 words in length, exclusive of tables, maps,
bibliographies and appendices.
Michael Papasimeon
January 2009
vi Declaration
Preface
The research undertaken as part of this thesis was sponsored by the Defence
Science and Technology Organisation (DSTO), the research and development
armoftheAustralianDepartmentofDefence. Thethesishasbeenundertakenas
partofalargerresearchprogramintointelligentagentsandmulti-agentsystems
going back to the early 1990s. The research program aims to better model
the situational awareness of computational representations of fighter pilots in
military simulations.
Thesesimulationsareusedtoconductoperationsresearchstudies,theresults
of which are used to provide advice to the Australian Defence Force (and in
particulartheRoyalAustralianAirForce). Thisadviceisusedtomakedecisions
ontheacquisitionofnewmilitaryaircraftandtodevelopnewtacticalprocedures
and concepts of operations for aircraft in service.
The research which motivated this thesis led to the deployment of a number
of large scale and complex multi-agent simulations making use of agent pro-
gramming languages based on the BDI (Beliefs, Desires and Intentions) model
of agent reasoning. It has also led to further research in a number of closely
relatedareas. Thisincludedmodellingteamandorganisationalsystemsinmulti-
agentsimulation, modellingagentrecognitionofintentionandinthecaseofthis
thesis, modelling the interaction between agents and the virtual environments
in which they are situated.
Some of the ideas described in this thesis relating to the use of affordances
in intelligent environments that are suitable and accessible to computational
agents were first presented [111] at the Australian Cognitive Science Conference
in 2002 (First year of my part-time PhD candidature).
• M. Papasimeon. Intelligent Environments for Agents, 2002 Australian
Cognitive Science Conference (OzCogSci ’02), Fremantle, Western Aus-
tralia, Australia.
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As part of the thesis, a prototype multi-agent military simulation has been
developed, named Human Agent Virtual Environment (HAVE). The develop-
ment of the HAVE multi-agent simulation is described in Chapter 2 and was
originallypublishedasthefollowingconferencepaperintheAAMASconference
in 2007.
• M. Papasimeon, A. R. Pearce, Simon Goss, Clint Heinze and Tim Patter-
son. TheHumanAgentVirtualEnvironment,InternationalConferenceon
Autonomous Agents and Multi-Agent Systems (AAMAS 2007), pp. 108,
Honolulu, Hawaii, USA, 2007.
Elements of the thesis have also appeared in other refereed publications as
follows.
• Clint Heinze, Michael Papasimeon, Simon Goss, Martin Cross, and Rus-
sell Connell. Simulating Fighter Pilots. In Simon G. Thompson Michal
PechoucekandHolgerVoos, editors, Defence Industry Applications of Au-
tonomous Agents and Multi-Agent Systems, Whitestein Series in Software
Agent Technologies and Autonomic Computing. Birkh auser Basel, 2008.
• M. Papasimeon and C. Heinze. Extending the UML for Designing Jack
Agents, 2001 Australian Software Engineering Conference (ASWEC), pp
89–97, 2001
• S. Goss and C. Heinze and M. Papasimeon and A. R. Pearce and L. Ster-
ling. The Importance of Being Purposive: Towards Reuse in Agent Ori-
entedInformationSystemsWorkshop on Agent Oriented Information Sys-
tems (AOIS 2003), Melbourne, Australia. P. Giorgini and B. Henderson-
Sellers and M. Winikoff (eds), Lecture Notes in Artificial Intelligence
(LNAI), pp. 110–125, 2004
• C. Heinze, M. Papasimeon, and S Goss. Issues in Modelling Sensor Fusion
in Agent Based Simulation of Air Operations. In Proceedings of the Sixth
International Conference on Information Fusion (FUSION ’03), pp 296-
301, Cairns, Australia, 2003.
• C. Heinze and M. Cross and S. Goss and T. Josefsson and I. Lloyd and
G. Murray and M. Papasimeon and M. Turner. Agents of Change: The
Impact of Intelligent Agent Technology on the Analysis of Air Opera-
tions, Advances in Intelligent Systems for Defence, Edition 1, L. Jain, N.
ix
Ichalkaranje and G. Tonfoni (eds), pp 229-264, World Scientific, Series on
Innovative Intelligence, Vol. 2, 2002
• C. Heinze and M. Papasimeon and S. Goss. Specifying Agent Behavior
with Use Cases, In Proceedings of Pacific Rim Internation International
Workshop on Multi-Agents (PRIMA 2000), pp. 128–142, 2000
A number of photos appearing in figures in this thesis are copyright the
Commonwealth of Australia (2008) andhave been obtained from the Australian
DepartmentofDefenceImageGallerywebsite. Theimagegalleryandassociated
copyright notice can be found at the following URLs.
• http://www.defence.gov.au/media/galleries/index.htm
• http://www.defence.gov.au/footer/copyright.htm
The photos in question appear in the following figures:
• Figure 1.4 ((above) photo of flight simulator) and
• Figure 2.2 (photos of F/A-18 Hornet and Army JTACs).
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