Brian S. Logan

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We present an agent-based model of the key activities of a troop of chacma baboons (Papio hamadryas ursinus) based on the data collected at De Hoop Nature Reserve in South Africa. We analyse the predictions of the model in terms of how well it is able to duplicate the observed activity patterns of the animals and the relationship between the parameters that(More)
The efficient simulation of a multi-agent system presents particular challenges which are not addressed by standard parallel discrete event simulation (PDES) models and techniques. While the modelling and simulation of agents, at least at a coarse grain, is relatively straightforward, it is harder to apply conventional PDES approaches to the simulation of(More)
The paper presents a load management mechanism for distributed simulations of multi-agent systems. The mechanism minimizes the cost of accessing the shared state in the distributed simulation by dynamically redistributing shared state variables according to the access pattern of the simulation model. To evaluate the effectiveness and performance of the(More)
In this article we describe HLA_AGENT, a tool for the distributed simulation of agent-based systems, which integrates the SIM_AGENT agent toolkit and the High Level Architecture (HLA) simulator interoperability framework. HLA_AGENT offers enhanced simulation scalability and allows interoperation with other HLA-compliant simulators, promoting simulation(More)
In this paper we present a throttling mechanism for optimistic simulations of multi-agent systems, which delays read accesses to the shared simulation state that are likely to be rolled back. We develop a decision-theoretic model of rollback and show how this can be used to derive the optimal time to delay a read event so as to minimize the expected overall(More)
Bacteria communicate through small diffusible molecules in a process known as quorum sensing. Quorum-sensing inhibitors are compounds which interfere with this, providing a potential treatment for infections associated with bacterial biofilms. We present an individual-based computational model for a developing biofilm. Cells are aggregated into particles(More)
In previous work we presented the DTRD algorithm, an optimistic synchronisation algorithm for parallel discrete event simulation of multi-agent systems, and showed that it outperforms Time Warp and time windows on range of test cases. DTRD uses a decision theoretic model of rollback to derive an optimal time to delay read event so as to maximise the rate of(More)
Decentralised, event-driven distributed simulation is particularly suitable for modelling systems with inherent asynchronous parallelism, such as agentbased systems. However the efficient simulation of multi-agent systems presents particular challenges which are not addressed by standard parallel discrete event simulation (PDES) models and techniques. PDES(More)
In this paper we present a detailed analysis of the performance of the Decision Theoretic Read Delay (DTRD) optimistic synchronisation algorithm for simulations of Multi- Agent Systems. We develop an abstract characterisation of the access patterns found in MAS simulations based on the simulation's degree of coupling and skew. Using this characterisation,(More)