Publications
2009
Theodoropoulos, Georgios K; Minson, Rob; Ewald, Roland; Lees, Michael
Book Chapter
In: Uhrmacher, Adelinde M; Weyns, Danny (Ed.): Multi-Agent Systems: Simulation and Applications, Chapter Simulation, CRC Press, Inc., Boca Raton, FL, USA, 1st, 2009, ISBN: 1420070231, 9781420070231.
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author = {Georgios K Theodoropoulos and Rob Minson and Roland Ewald and Michael Lees},
editor = {Adelinde M Uhrmacher and Danny Weyns},
isbn = {1420070231, 9781420070231},
year = {2009},
date = {2009-01-01},
booktitle = {Multi-Agent Systems: Simulation and Applications},
publisher = {CRC Press, Inc.},
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chapter = {Simulation},
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Stevens, David; Power, Henry; Lees, Michael; Morvan, Herve
In: Transport in Porous Media, 79 (2), pp. 149–169, 2009.
@article{springerlink:10.1007/s11242-008-9303-z,
title = {A Meshless Solution Technique for the Solution of 3D Unsaturated Zone Problems, Based on Local Hermitian Interpolation with Radial Basis Functions},
author = {David Stevens and Henry Power and Michael Lees and Herve Morvan},
url = {http://dx.doi.org/10.1007/s11242-008-9303-z},
year = {2009},
date = {2009-01-01},
journal = {Transport in Porous Media},
volume = {79},
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pages = {149--169},
publisher = {Springer Netherlands},
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2008
Chen, Dan; Ewald, Roland; Theodoropoulos, Georgios K; Minson, Robert; Oguara, Ton; Lees, Michael; Logan, Brian; Uhrmacher, Adelinde M
Data access in distributed simulations of multi-agent systems Journal Article
In: Journal of Systems and Software, 81 (12), pp. 2345–2360, 2008.
@article{DBLP:journals/jss/ChenETMOLLU08,
title = {Data access in distributed simulations of multi-agent systems},
author = {Dan Chen and Roland Ewald and Georgios K Theodoropoulos and Robert Minson and Ton Oguara and Michael Lees and Brian Logan and Adelinde M Uhrmacher},
url = {http://linkinghub.elsevier.com/retrieve/pii/S0164121208000976},
doi = {10.1016/j.jss.2008.04.041},
year = {2008},
date = {2008-12-01},
journal = {Journal of Systems and Software},
volume = {81},
number = {12},
pages = {2345--2360},
abstract = {Distributed simulation has emerged as an important instrument for studying large-scale complex systems. Such systems inherently consist of a large number of components, which operate in a large shared state space interacting with it in highly dynamic and unpredictable ways. Optimising access to the shared state space is crucial for achieving efficient simulation executions. Data accesses may take two forms: locating data according to a set of attribute value ranges (range query) or locating a particular state variable from the given identifier (ID query and update). This paper proposes two alternative routing approaches, namely the address-based approach, which locates data according to their address information, and the range-based approach, whose operation is based on looking up attribute value range information along the paths to the destinations. The two algorithms are discussed and analysed in the context of PDES-MAS, a framework for the distributed simulation of multi-agent systems, which uses a hierarchical infrastructure to manage the shared state space. The paper introduces a generic meta-simulation framework which is used to perform a quantitative comparative analysis of the proposed algorithms under various circumstances.},
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Distributed simulation has emerged as an important instrument for studying large-scale complex systems. Such systems inherently consist of a large number of components, which operate in a large shared state space interacting with it in highly dynamic and unpredictable ways. Optimising access to the shared state space is crucial for achieving efficient simulation executions. Data accesses may take two forms: locating data according to a set of attribute value ranges (range query) or locating a particular state variable from the given identifier (ID query and update). This paper proposes two alternative routing approaches, namely the address-based approach, which locates data according to their address information, and the range-based approach, whose operation is based on looking up attribute value range information along the paths to the destinations. The two algorithms are discussed and analysed in the context of PDES-MAS, a framework for the distributed simulation of multi-agent systems, which uses a hierarchical infrastructure to manage the shared state space. The paper introduces a generic meta-simulation framework which is used to perform a quantitative comparative analysis of the proposed algorithms under various circumstances.
Dinh, Tien Tuan Anh; Lees, Michael; Theodoropoulos, Georgios; Minson, Rob
Large Scale Distributed Simulation of p2p Networks Inproceedings
In: 16th Euromicro Conference on Parallel, Distributed and Network-Based Processing (PDP 2008), pp. 499–507, IEEE, 2008, ISBN: 978-0-7695-3089-5.
@inproceedings{DBLP:conf/pdp/DinhLTM08,
title = {Large Scale Distributed Simulation of p2p Networks},
author = {Tien Tuan Anh Dinh and Michael Lees and Georgios Theodoropoulos and Rob Minson},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4457163},
doi = {10.1109/PDP.2008.67},
isbn = {978-0-7695-3089-5},
year = {2008},
date = {2008-01-01},
booktitle = {16th Euromicro Conference on Parallel, Distributed and Network-Based Processing (PDP 2008)},
pages = {499--507},
publisher = {IEEE},
abstract = {P2P systems have witnessed phenomenal development in recent years, evaluating and analysing new and existing new algorithms and techniques is a key issue for developers of p2p systems. In this context Simulation is an important tool for p2p developers. However, such systems are often very large and few existing simulators offer the ability to execute systems of real world size. In this paper we present a tool for executing large scale simulation of p2p systems which scale effectively, only limited by the amount of computational resource available (memory and CPU). This is achieved through the application of parallel discrete event simulation techniques to an existing, already scalable simulator, peersim. We show results from a case study using the chord p2p protocol, indicating good scalability both in terms of size (memory) and execution time (CPU).},
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P2P systems have witnessed phenomenal development in recent years, evaluating and analysing new and existing new algorithms and techniques is a key issue for developers of p2p systems. In this context Simulation is an important tool for p2p developers. However, such systems are often very large and few existing simulators offer the ability to execute systems of real world size. In this paper we present a tool for executing large scale simulation of p2p systems which scale effectively, only limited by the amount of computational resource available (memory and CPU). This is achieved through the application of parallel discrete event simulation techniques to an existing, already scalable simulator, peersim. We show results from a case study using the chord p2p protocol, indicating good scalability both in terms of size (memory) and execution time (CPU).
Lees, Michael; Logan, Brian; Theodoropoulos, G
Using Access Patterns to Analyze the Performance of Optimistic Synchronization Algorithms in Simulations of MAS Journal Article
In: SIMULATION, 84 (10-11), pp. 481–492, 2008.
@article{DBLP:journals/simulation/LeesLT08,
title = {Using Access Patterns to Analyze the Performance of Optimistic Synchronization Algorithms in Simulations of MAS},
author = {Michael Lees and Brian Logan and G Theodoropoulos},
url = {http://sim.sagepub.com/cgi/doi/10.1177/0037549708096691},
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year = {2008},
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volume = {84},
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abstract = {We present a detailed analysis of the performance of the Decision Theoretic Read Delay (DTRD) optimistic synchronization algorithm for simulations of multi-agent systems (MAS). We develop an abstract characterization of the access patterns found in MAS simulations based on the simulation's degree of coupling and skew. Using this characterization, we generated stereotypical test cases which we used to compare the performance of the DTRD algorithm with that of Time Warp and time windows. To determine if the test cases reliably predict performance in a real agent simulation, we compared the predictions made by the test cases with performance results from the Boids agent simulation benchmark for a range of simulation parameters. The results indicate that the test cases are useful predictors of performance in real agent simulations, that DTRD adapts to the mixtures of coupling cases found in real agent simulations and is capable of tracking changes in coupling during the simulation.},
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We present a detailed analysis of the performance of the Decision Theoretic Read Delay (DTRD) optimistic synchronization algorithm for simulations of multi-agent systems (MAS). We develop an abstract characterization of the access patterns found in MAS simulations based on the simulation's degree of coupling and skew. Using this characterization, we generated stereotypical test cases which we used to compare the performance of the DTRD algorithm with that of Time Warp and time windows. To determine if the test cases reliably predict performance in a real agent simulation, we compared the predictions made by the test cases with performance results from the Boids agent simulation benchmark for a range of simulation parameters. The results indicate that the test cases are useful predictors of performance in real agent simulations, that DTRD adapts to the mixtures of coupling cases found in real agent simulations and is capable of tracking changes in coupling during the simulation.
Orsini, P; Power, H; Lees, M; Morvan, H
A Control Volume Radial Basis Function Techniques for the Numerical Simulation of Saturated Flows in Semi-confined Aquifer Journal Article
In: Transport in Porous Media, 79 (2), pp. 171–196, 2008.
@article{springerlink:10.1007/s11242-008-9304-y,
title = {A Control Volume Radial Basis Function Techniques for the Numerical Simulation of Saturated Flows in Semi-confined Aquifer},
author = {P Orsini and H Power and M Lees and H Morvan},
url = {http://dx.doi.org/10.1007/s11242-008-9304-y http://link.springer.com/10.1007/s11242-008-9304-y},
doi = {10.1007/s11242-008-9304-y},
year = {2008},
date = {2008-01-01},
journal = {Transport in Porous Media},
volume = {79},
number = {2},
pages = {171--196},
publisher = {Springer Netherlands},
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2007
Lees, Michael; Logan, Brian; King, John
Multiscale models of bacterial populations Inproceedings
In: Henderson, Shane G; Biller, Bahar; Hsieh, Ming-Hua; Shortle, John; Tew, Jeffrey D; Barton, Russell R (Ed.): 2007 Winter Simulation Conference, pp. 881–890, IEEE, 2007, ISBN: 978-1-4244-1305-8.
@inproceedings{DBLP:conf/wsc/LeesLK07,
title = {Multiscale models of bacterial populations},
author = {Michael Lees and Brian Logan and John King},
editor = {Shane G Henderson and Bahar Biller and Ming-Hua Hsieh and John Shortle and Jeffrey D Tew and Russell R Barton},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4419684},
doi = {10.1109/WSC.2007.4419684},
isbn = {978-1-4244-1305-8},
year = {2007},
date = {2007-12-01},
booktitle = {2007 Winter Simulation Conference},
pages = {881--890},
publisher = {IEEE},
abstract = {We present a hybrid model of the interactions within (multiple-species) populations of bacteria in a developing biofilm which integrates continuum models of population processes (e.g., diffusion of substrates and signalling molecules) with individual-based models of cellular processes (notably growth, division, displacement, and up- regulation). The cell level models combine both aggregated models of continuous processes (growth, division and displacement) for small collections of cells and individual-cell level models of quorum sensing molecule (QSM) sensing, production and up-regulation which encompass both stochastic and discrete processes. The use of both aggregated and individual models of cellular processes allows the resolution of the model to be tailored for a particular modelling problem, while at the same time remaining computationally tractable.},
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We present a hybrid model of the interactions within (multiple-species) populations of bacteria in a developing biofilm which integrates continuum models of population processes (e.g., diffusion of substrates and signalling molecules) with individual-based models of cellular processes (notably growth, division, displacement, and up- regulation). The cell level models combine both aggregated models of continuous processes (growth, division and displacement) for small collections of cells and individual-cell level models of quorum sensing molecule (QSM) sensing, production and up-regulation which encompass both stochastic and discrete processes. The use of both aggregated and individual models of cellular processes allows the resolution of the model to be tailored for a particular modelling problem, while at the same time remaining computationally tractable.
Lees, Michael; Logan, Brian; King, John
HLA Simulation of Agent-Based Bacterial Models Inproceedings
In: Proceedings of the 2007 European Simulation Interoperability Workshop, Simulation Interoperability Standards Organisation Genoa, 2007.
@inproceedings{Lees//:07c,
title = {HLA Simulation of Agent-Based Bacterial Models},
author = {Michael Lees and Brian Logan and John King},
url = {http://www.agents.cs.nott.ac.uk/node/87},
year = {2007},
date = {2007-06-01},
booktitle = {Proceedings of the 2007 European Simulation Interoperability Workshop},
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Lees, Michael; Logan, Brian; Theodoropoulos, Georgios
Distributed simulation of agent-based systems with HLA Journal Article
In: ACM Transactions on Modeling and Computer Simulation, 17 (3), pp. 11–es, 2007.
@article{DBLP:journals/tomacs/LeesLT07,
title = {Distributed simulation of agent-based systems with HLA},
author = {Michael Lees and Brian Logan and Georgios Theodoropoulos},
url = {http://portal.acm.org/citation.cfm?doid=1243991.1243992},
doi = {10.1145/1243991.1243992},
year = {2007},
date = {2007-01-01},
journal = {ACM Transactions on Modeling and Computer Simulation},
volume = {17},
number = {3},
pages = {11--es},
abstract = {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 reuse. Using a simple Tileworld example, we show how HLA_AGENT can be used to flexibly distribute a SIM_AGENT simulation so as to exploit available computing resources. We present experimental results that illustrate the performance of HLA_AGENT on a Linux cluster running a distributed version of Tileworld and compare this with the original nondistributed SIM_AGENT version.},
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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 reuse. Using a simple Tileworld example, we show how HLA_AGENT can be used to flexibly distribute a SIM_AGENT simulation so as to exploit available computing resources. We present experimental results that illustrate the performance of HLA_AGENT on a Linux cluster running a distributed version of Tileworld and compare this with the original nondistributed SIM_AGENT version.
Lees, Michael; Logan, Brian; King, John
BacGrid: simulations of bacteria using the grid Inproceedings
In: BMC Systems Biology, pp. S5, 2007.
@inproceedings{Lees//:07d,
title = {BacGrid: simulations of bacteria using the grid},
author = {Michael Lees and Brian Logan and John King},
url = {http://www.biomedcentral.com/1752-0509/1/S1/S5},
doi = {10.1186/1752-0509-1-S1-S5},
year = {2007},
date = {2007-01-01},
booktitle = {BMC Systems Biology},
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2006
Lees, Michael; Logan, Brian; Chen, Dan; Oguara, Ton; Theodoropoulos, Georgios
Analysing Probabilistically Constrained Optimism Inproceedings
In: 2006 Tenth IEEE International Symposium on Distributed Simulation and Real-Time Applications, pp. 201–208, IEEE, 2006, ISBN: 0-7695-2697-7.
@inproceedings{DBLP:conf/dsrt/LeesLCOT06,
title = {Analysing Probabilistically Constrained Optimism},
author = {Michael Lees and Brian Logan and Dan Chen and Ton Oguara and Georgios Theodoropoulos},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4020804},
doi = {10.1109/DS-RT.2006.10},
isbn = {0-7695-2697-7},
year = {2006},
date = {2006-01-01},
booktitle = {2006 Tenth IEEE International Symposium on Distributed Simulation and Real-Time Applications},
pages = {201--208},
publisher = {IEEE},
abstract = {Email Print Request Permissions Save to Project 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 LVT progression. The algorithm assumes that the inter-arrival times (both virtual and real) of events are normally distributed. In this paper we present a more detailed evaluation of the DTRD algorithm, and specifically how the performance of the algorithm is affected when the inter-arrival times do not follow the assumed distributions. Our analysis suggests that the performance of the algorithm is relatively insensitive to events whose inter-arrival times are not normally distributed. However as the variance of the input events increases its performance degrades to that of Time Warp. Our approach to evaluation is general, and we outline how the analysis may be applied to other decision theoretic algorithms},
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Email Print Request Permissions Save to Project 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 LVT progression. The algorithm assumes that the inter-arrival times (both virtual and real) of events are normally distributed. In this paper we present a more detailed evaluation of the DTRD algorithm, and specifically how the performance of the algorithm is affected when the inter-arrival times do not follow the assumed distributions. Our analysis suggests that the performance of the algorithm is relatively insensitive to events whose inter-arrival times are not normally distributed. However as the variance of the input events increases its performance degrades to that of Time Warp. Our approach to evaluation is general, and we outline how the analysis may be applied to other decision theoretic algorithms
Logan, Brian; Lees, Michael; King, John
BacGrid: Large Scale Systems Biology Simulation on the Grid Inproceedings
In: Winter Simulation Conference, Track on Modelling and Simulation in Computational Biology, Monterey, CA USA, 2006.
@inproceedings{Logan//:06a,
title = {BacGrid: Large Scale Systems Biology Simulation on the Grid},
author = {Brian Logan and Michael Lees and John King},
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address = {Monterey, CA USA},
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Ewald, Roland; Chen, Dan; Theodoropoulos, G K; Lees, Michael; Logan, Brian; Oguara, Ton; Uhrmacher, A M
Performance Analysis of Shared Data Access Algorithms for Distributed Simulation of Multi-Agent Systems Inproceedings
In: 20th Workshop on Principles of Advanced and Distributed Simulation (PADS'06), pp. 29–36, IEEE, 2006, ISBN: 0-7695-2587-3.
@inproceedings{DBLP:conf/pads/EwaldCTLLOU06,
title = {Performance Analysis of Shared Data Access Algorithms for Distributed Simulation of Multi-Agent Systems},
author = {Roland Ewald and Dan Chen and G K Theodoropoulos and Michael Lees and Brian Logan and Ton Oguara and A M Uhrmacher},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=1630706},
doi = {10.1109/PADS.2006.29},
isbn = {0-7695-2587-3},
year = {2006},
date = {2006-01-01},
booktitle = {20th Workshop on Principles of Advanced and Distributed Simulation (PADS'06)},
pages = {29--36},
publisher = {IEEE},
abstract = {Distributed simulation is an important instrument for studying multi-agent systems (MAS). Such large scale MAS simulations often have a large shared state space. Moreover, the shared state and the access pattern of agent simulations both are highly dynamic and unpredictable. Optimising access to the shared data is crucial for achieving efficient simulation executions. PDES-MAS is a framework for distributed simulation of MAS, which uses a hierarchical infrastructure to manage the shared data. In order to enable agent simulations to access distributed shared data efficiently, this paper proposes two routing algorithms, namely the address-based routing and the range-based routing. The paper introduces a meta-simulation approach to evaluate the characteristics of both solutions and provides a quantitative comparative analysis of the proposed algorithms.},
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pubstate = {published},
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Distributed simulation is an important instrument for studying multi-agent systems (MAS). Such large scale MAS simulations often have a large shared state space. Moreover, the shared state and the access pattern of agent simulations both are highly dynamic and unpredictable. Optimising access to the shared data is crucial for achieving efficient simulation executions. PDES-MAS is a framework for distributed simulation of MAS, which uses a hierarchical infrastructure to manage the shared data. In order to enable agent simulations to access distributed shared data efficiently, this paper proposes two routing algorithms, namely the address-based routing and the range-based routing. The paper introduces a meta-simulation approach to evaluate the characteristics of both solutions and provides a quantitative comparative analysis of the proposed algorithms.
Lees, Michael; Logan, Brian; Theodoropoulos, G K
Agents, games and HLA Journal Article
In: Simulation Modelling Practice and Theory, 14 (6), pp. 752–767, 2006.
@article{DBLP:journals/simpra/LeesLT06,
title = {Agents, games and HLA},
author = {Michael Lees and Brian Logan and G K Theodoropoulos},
url = {http://linkinghub.elsevier.com/retrieve/pii/S1569190X05001267},
doi = {10.1016/j.simpat.2005.10.007},
year = {2006},
date = {2006-01-01},
journal = {Simulation Modelling Practice and Theory},
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abstract = {Over the past decade, there has been a growing interest in utilising intelligent agents in computer games and virtual environments. At the same time, computer game research and development has increasingly drawn on technologies and techniques originally developed in the large scale distributed simulation community, such as the HLA IEEE standard for simulator interoperability. In this paper, we address a central issue for HLA-based games, namely the development of HLA-compliant game agents. We present hla_agent, an HLA-compliant version of the sim_agent toolkit for building cognitively rich agents. We outline the changes necessary to the sim_agent toolkit to allow integration with the HLA, and show that, given certain reasonable assumptions, all necessary code can be generated automatically from the FOM and the object class publications and subscriptions. The integration is transparent in the sense that the existing sim_agent code runs unmodified and the agents are unaware that other parts of the system are running remotely. We present some preliminary performance results, which indicate that the overhead introduced by the HLA extension is modest even for lightweight agents with limited computational requirements.},
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Over the past decade, there has been a growing interest in utilising intelligent agents in computer games and virtual environments. At the same time, computer game research and development has increasingly drawn on technologies and techniques originally developed in the large scale distributed simulation community, such as the HLA IEEE standard for simulator interoperability. In this paper, we address a central issue for HLA-based games, namely the development of HLA-compliant game agents. We present hla_agent, an HLA-compliant version of the sim_agent toolkit for building cognitively rich agents. We outline the changes necessary to the sim_agent toolkit to allow integration with the HLA, and show that, given certain reasonable assumptions, all necessary code can be generated automatically from the FOM and the object class publications and subscriptions. The integration is transparent in the sense that the existing sim_agent code runs unmodified and the agents are unaware that other parts of the system are running remotely. We present some preliminary performance results, which indicate that the overhead introduced by the HLA extension is modest even for lightweight agents with limited computational requirements.
Lees, Michael; Logan, Brian; Dan, C; Oguara, Ton; Theodoropoulos, G
Analysing the Performance of Optimistic Synchronisation Algorithms in Simulations of Multi-Agent Systems Inproceedings
In: 20th Workshop on Principles of Advanced and Distributed Simulation (PADS'06), pp. 37–44, IEEE, 2006, ISBN: 0-7695-2587-3.
@inproceedings{DBLP:conf/pads/LeesLDOT06,
title = {Analysing the Performance of Optimistic Synchronisation Algorithms in Simulations of Multi-Agent Systems},
author = {Michael Lees and Brian Logan and C Dan and Ton Oguara and G Theodoropoulos},
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booktitle = {20th Workshop on Principles of Advanced and Distributed Simulation (PADS'06)},
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abstract = {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, we generated stereotypical test cases which we used to compare the performance of the DTRD algorithm with that of Time Warp and time windows. To determine if the test cases reliably predict performance in a real agent simulation, we compared the predictions made by the test cases with performance results from the Boids agent simulation benchmark for a range of simulation parameters. The results indicate that DTRD adapts to the mixtures of coupling cases found in real agent simulations and is capable of tracking changes in coupling during the simulation.},
keywords = {},
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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, we generated stereotypical test cases which we used to compare the performance of the DTRD algorithm with that of Time Warp and time windows. To determine if the test cases reliably predict performance in a real agent simulation, we compared the predictions made by the test cases with performance results from the Boids agent simulation benchmark for a range of simulation parameters. The results indicate that DTRD adapts to the mixtures of coupling cases found in real agent simulations and is capable of tracking changes in coupling during the simulation.
2005
Lees, Michael; Logan, Brian; Theodoropoulos, G
Decision-Theoretic Throttling for Optimistic Simulations of Multi-Agent Systems Inproceedings
In: Ninth IEEE International Symposium on Distributed Simulation and Real-Time Applications, pp. 171–178, IEEE, 2005, ISBN: 0-7695-2462-1.
@inproceedings{DBLP:conf/dsrt/LeesLDOT05,
title = {Decision-Theoretic Throttling for Optimistic Simulations of Multi-Agent Systems},
author = {Michael Lees and Brian Logan and G Theodoropoulos},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=1530667},
doi = {10.1109/DISTRA.2005.16},
isbn = {0-7695-2462-1},
year = {2005},
date = {2005-01-01},
booktitle = {Ninth IEEE International Symposium on Distributed Simulation and Real-Time Applications},
pages = {171--178},
publisher = {IEEE},
abstract = {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 execution time of the simulation. We briefly describe an implementation of this approach in ASSK, a distributed simulation kernel developed to investigate synchronization mechanisms for MAS simulation, and report the results of preliminary experiments to evaluate the effectiveness of our approach.},
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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 execution time of the simulation. We briefly describe an implementation of this approach in ASSK, a distributed simulation kernel developed to investigate synchronization mechanisms for MAS simulation, and report the results of preliminary experiments to evaluate the effectiveness of our approach.
Chen, Dan; Theodoropoulos, G; Logan, Brian; Lees, Michael
An Adaptive Load Management Mechanism for Distributed Simulation of Multi-agent Systems Inproceedings
In: Ninth IEEE International Symposium on Distributed Simulation and Real-Time Applications, pp. 179–186, IEEE, 2005, ISBN: 0-7695-2462-1.
@inproceedings{DBLP:conf/dsrt/OguaraCTLL05,
title = {An Adaptive Load Management Mechanism for Distributed Simulation of Multi-agent Systems},
author = {Dan Chen and G Theodoropoulos and Brian Logan and Michael Lees},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=1530668},
doi = {10.1109/DISTRA.2005.9},
isbn = {0-7695-2462-1},
year = {2005},
date = {2005-01-01},
booktitle = {Ninth IEEE International Symposium on Distributed Simulation and Real-Time Applications},
pages = {179--186},
publisher = {IEEE},
abstract = {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 mechanism, a series of benchmark experiments were performed using the PDES-MAS framework for distributed simulation of multi-agent systems. Although preliminary, the results indicate that the proposed mechanism significantly reduces the overall access cost of the system.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
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 mechanism, a series of benchmark experiments were performed using the PDES-MAS framework for distributed simulation of multi-agent systems. Although preliminary, the results indicate that the proposed mechanism significantly reduces the overall access cost of the system.
2004
Lees, Michael; Logan, Brian; Theodoropoulos, Georgios
Time Windows in Multi-Agent Distributed Simulation Inproceedings
In: Proceedings of the 5th EUROSIM Congress on Modelling and Simulation (EuroSim'04), Paris, 2004.
@inproceedings{Lees//:04d,
title = {Time Windows in Multi-Agent Distributed Simulation},
author = {Michael Lees and Brian Logan and Georgios Theodoropoulos},
year = {2004},
date = {2004-01-01},
booktitle = {Proceedings of the 5th EUROSIM Congress on Modelling and Simulation (EuroSim'04)},
address = {Paris},
abstract = {In this paper we describe a method for optimistic parallel discrete event simulation for multi-agent systems. We present an adaptive metric that calculates the appropriate degree of optimism for an agent process based on the reads and writes made to the shared state by that agent. We conclude by showing how results from our investigations into the application of moving time windows in agent simulation affects future development of the adaptive metric.},
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In this paper we describe a method for optimistic parallel discrete event simulation for multi-agent systems. We present an adaptive metric that calculates the appropriate degree of optimism for an agent process based on the reads and writes made to the shared state by that agent. We conclude by showing how results from our investigations into the application of moving time windows in agent simulation affects future development of the adaptive metric.
Lees, Michael; Logan, Brian; Minson, Rob; Oguara, Ton; Theodoropoulos, Georgios
Modelling Environments for Distributed Simulation Inproceedings
In: Weyns, Danny; Parunak, Van Dyke H; Michel, Fabien (Ed.): Environments for Multi-Agent Systems: Proceedings of the the First International Workshop (E4MAS'04), pp. 150–167, Springer, 2004, ISBN: 3-540-24575-8.
@inproceedings{Lees//:04c,
title = {Modelling Environments for Distributed Simulation},
author = {Michael Lees and Brian Logan and Rob Minson and Ton Oguara and Georgios Theodoropoulos},
editor = {Danny Weyns and Van Dyke H Parunak and Fabien Michel},
doi = {10.1007/978-3-540-32259-7_8},
isbn = {3-540-24575-8},
year = {2004},
date = {2004-01-01},
booktitle = {Environments for Multi-Agent Systems: Proceedings of the the First International Workshop (E4MAS'04)},
number = {3374},
pages = {150--167},
publisher = {Springer},
series = {LNAI},
abstract = {Decentralised, event-driven distributed simulation is particularly suitable for modelling systems with inherent asynchronous parallelism, such as agent-based 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 approaches based on the logical process paradigm assume a fixed decomposition into processes, each of which maintains its own portion of the state of the simulation. The interaction between the processes is fixed in advance and does not change during the simulation. In contrast, simulations of MAS typically have a large shared state, the agents' environment, which is only loosely associated with any particular process. In this paper, we present a model of the shared state of a distributed MAS simulation of situated agents. We consider the problems of efficient sensing, parallel actions and action conflicts, and present preliminary work on an approach to the simulation of the environment which addresses these issues.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Decentralised, event-driven distributed simulation is particularly suitable for modelling systems with inherent asynchronous parallelism, such as agent-based 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 approaches based on the logical process paradigm assume a fixed decomposition into processes, each of which maintains its own portion of the state of the simulation. The interaction between the processes is fixed in advance and does not change during the simulation. In contrast, simulations of MAS typically have a large shared state, the agents' environment, which is only loosely associated with any particular process. In this paper, we present a model of the shared state of a distributed MAS simulation of situated agents. We consider the problems of efficient sensing, parallel actions and action conflicts, and present preliminary work on an approach to the simulation of the environment which addresses these issues.
Lees, Michael; Logan, Brian; Minson, Rob; Oguara, Ton; Theodoropoulos, Georgios K
Distributed Simulation of MAS Inproceedings
In: Davidsson, Paul; Logan, Brian; Takadama, Keiki (Ed.): Multi-Agent and Multi-Agent-Based Simulation, Joint Workshop MABS 2004, New York, NY, USA, July 19, 2004, Revised Selected Papers, pp. 25–36, Springer, 2004, ISBN: 3-540-25262-2.
@inproceedings{DBLP:conf/mabs/LeesLMOT04,
title = {Distributed Simulation of MAS},
author = {Michael Lees and Brian Logan and Rob Minson and Ton Oguara and Georgios K Theodoropoulos},
editor = {Paul Davidsson and Brian Logan and Keiki Takadama},
doi = {10.1007/978-3-540-32243-6_3},
isbn = {3-540-25262-2},
year = {2004},
date = {2004-01-01},
booktitle = {Multi-Agent and Multi-Agent-Based Simulation, Joint Workshop MABS 2004, New York, NY, USA, July 19, 2004, Revised Selected Papers},
volume = {3415},
pages = {25--36},
publisher = {Springer},
series = {Lecture Notes in Computer Science},
abstract = {The efficient simulation of multi-agent systems presents particular challenges which are not addressed by current 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 PDES approaches to the simulation of the agents' environment. In conventional PDES approaches a system is modelled as a set of logical processes (LPs). Each LP maintains its own portion of the state of the simulation and interacts with a small number of other LPs. The interaction between the LPs is assumed to be known in advance and does not change during the simulation. In contrast, the environment of a MAS is read and updated by agent and environment LPs in ways which depend on the evolution of the simulation. As a result, MAS simulations typically have a large shared state which is not associated with any particular agent or environment LP. In [1] we proposed a new approach to the distributed simulation of MAS in which the shared state is maintained by a tree of additional logical processes called Communication Logical Processes (CLP). In this paper we refine this model by giving precise definitions of a set of operations which allow agent and environment LPs to interact with the shared state and briefly outline how these operations could be implemented by a CLP.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The efficient simulation of multi-agent systems presents particular challenges which are not addressed by current 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 PDES approaches to the simulation of the agents' environment. In conventional PDES approaches a system is modelled as a set of logical processes (LPs). Each LP maintains its own portion of the state of the simulation and interacts with a small number of other LPs. The interaction between the LPs is assumed to be known in advance and does not change during the simulation. In contrast, the environment of a MAS is read and updated by agent and environment LPs in ways which depend on the evolution of the simulation. As a result, MAS simulations typically have a large shared state which is not associated with any particular agent or environment LP. In [1] we proposed a new approach to the distributed simulation of MAS in which the shared state is maintained by a tree of additional logical processes called Communication Logical Processes (CLP). In this paper we refine this model by giving precise definitions of a set of operations which allow agent and environment LPs to interact with the shared state and briefly outline how these operations could be implemented by a CLP.
Lees, Michael; Logan, Brian; Oguara, Ton; Theodoropoulos, Georgios K
HLA_AGENT: Distributed Simulation of Agent-Based Systems with HLA Inproceedings
In: Bubak, Marian; van Albada, Dick G; Sloot, Peter M A; Dongarra, Jack (Ed.): Computational Science - ICCS 2004, 4th International Conference, Kraków, Poland, June 6-9, 2004, Proceedings, Part III, pp. 881–888, Springer, 2004, ISBN: 3-540-22116-6.
@inproceedings{DBLP:conf/iccS/LeesLOT04,
title = {HLA_AGENT: Distributed Simulation of Agent-Based Systems with HLA},
author = {Michael Lees and Brian Logan and Ton Oguara and Georgios K Theodoropoulos},
editor = {Marian Bubak and Dick G van Albada and Peter M A Sloot and Jack Dongarra},
isbn = {3-540-22116-6},
year = {2004},
date = {2004-01-01},
booktitle = {Computational Science - ICCS 2004, 4th International Conference, Kraków, Poland, June 6-9, 2004, Proceedings, Part III},
volume = {3038},
pages = {881--888},
publisher = {Springer},
series = {Lecture Notes in Computer Science},
keywords = {},
pubstate = {published},
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2003
Lees, Michael; Logan, Brian; Oguara, Ton; Theodoropoulos, Georgios
Simulating Agent-Based Systems with HLA: The case of SIM_AGENT -- Part II Inproceedings
In: Proceedings of the 2003 European Simulation Interoperability Workshop, European Office of Aerospace R&D Simulation Interoperability Standards Organisation and Society for Computer Simulation International, 2003.
@inproceedings{Lees//:03a,
title = {Simulating Agent-Based Systems with HLA: The case of SIM_AGENT -- Part II},
author = {Michael Lees and Brian Logan and Ton Oguara and Georgios Theodoropoulos},
year = {2003},
date = {2003-06-01},
booktitle = {Proceedings of the 2003 European Simulation Interoperability Workshop},
publisher = {Simulation Interoperability Standards Organisation and Society for Computer Simulation International},
organization = {European Office of Aerospace R&D},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Lees, Michael; Logan, Brian; Theodoropoulos, Georgios
Adaptive Optimistic Synchronisation for Multi-Agent Simulation Inproceedings
In: Al-Dabass, David (Ed.): Proceedings of the 17th European Simulation Multiconference (ESM 2003), pp. 77–82, Society for Modelling and Simulation International and Arbeitsgemeinschaft Simulation Society for Modelling and Simulation International, Delft, 2003, ISBN: 3-936150-25-7.
@inproceedings{Lees//:03c,
title = {Adaptive Optimistic Synchronisation for Multi-Agent Simulation},
author = {Michael Lees and Brian Logan and Georgios Theodoropoulos},
editor = {David Al-Dabass},
isbn = {3-936150-25-7},
year = {2003},
date = {2003-01-01},
booktitle = {Proceedings of the 17th European Simulation Multiconference (ESM 2003)},
pages = {77--82},
publisher = {Society for Modelling and Simulation International},
address = {Delft},
organization = {Society for Modelling and Simulation International and Arbeitsgemeinschaft Simulation},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2002
Lees, Michael; Logan, Brian; Theodoropoulos, Georgios
Simulating Agent-Based Systems with HLA: The case of SIM_AGENT Inproceedings
In: Proceedings of the 2002 European Simulation Interoperability Workshop, pp. 285–293, European Office of Aerospace R&D Simulation Interoperability Standards Organisation and Society for Computer Simulation International, 2002, ISBN: 1--930638--24--8.
@inproceedings{Lees//:02a,
title = {Simulating Agent-Based Systems with HLA: The case of SIM_AGENT},
author = {Michael Lees and Brian Logan and Georgios Theodoropoulos},
isbn = {1--930638--24--8},
year = {2002},
date = {2002-01-01},
booktitle = {Proceedings of the 2002 European Simulation Interoperability Workshop},
pages = {285--293},
publisher = {Simulation Interoperability Standards Organisation and Society for Computer Simulation International},
organization = {European Office of Aerospace R&D},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}