Publications
2014
Zhong, Jinghui; Luo, Linbo; Cai, Wentong; Lees, Michael
Automatic rule identification for agent-based crowd models through gene expression programming Inproceedings
In: 2014 international conference on Autonomous agents and multi-agent systems, pp. 1125–1125–1132–1132, International Foundation for Autonomous Agents and Multiagent Systems, 2014, ISBN: 978-1-4503-2738-1.
@inproceedings{Zhong2014,
title = {Automatic rule identification for agent-based crowd models through gene expression programming},
author = {Jinghui Zhong and Linbo Luo and Wentong Cai and Michael Lees},
url = {http://dl.acm.org/citation.cfm?id=2617388.2617425},
isbn = {978-1-4503-2738-1},
year = {2014},
date = {2014-05-01},
booktitle = {2014 international conference on Autonomous agents and multi-agent systems},
pages = {1125--1125--1132--1132},
publisher = {International Foundation for Autonomous Agents and Multiagent Systems},
abstract = {Agent-based modelling of human crowds has now become an important and active research field, with a wide range of applications such as military training, evacuation analysis and digital game. One of the significant and challenging tasks in agent-based crowd modelling is the design of decision rules for agents, so as to reproduce desired emergent phenomena behaviors. The common approach in agent-based crowd modelling is to design decision rules empirically based on model developers experiences and domain specific knowledge. In this paper, an evolutionary framework is proposed to automatically extract decision rules for agent-based crowd models, so as to reproduce an objective crowd behavior. To automate the rule extraction process, the problem of finding optimal decision rules from objective crowd behaviors is formulated as a symbolic regression problem. An evolutionary framework based on gene expression programming is developed to solve the problem. The proposed algorithm is tested using crowd evacuation simulations in three scenarios with differing complexity. Our results demonstrate the feasibility of the approach and shows that our algorithm is able to find decision rules for agents, which in turn can generate the prescribed macro-scale dynamics.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Agent-based modelling of human crowds has now become an important and active research field, with a wide range of applications such as military training, evacuation analysis and digital game. One of the significant and challenging tasks in agent-based crowd modelling is the design of decision rules for agents, so as to reproduce desired emergent phenomena behaviors. The common approach in agent-based crowd modelling is to design decision rules empirically based on model developers experiences and domain specific knowledge. In this paper, an evolutionary framework is proposed to automatically extract decision rules for agent-based crowd models, so as to reproduce an objective crowd behavior. To automate the rule extraction process, the problem of finding optimal decision rules from objective crowd behaviors is formulated as a symbolic regression problem. An evolutionary framework based on gene expression programming is developed to solve the problem. The proposed algorithm is tested using crowd evacuation simulations in three scenarios with differing complexity. Our results demonstrate the feasibility of the approach and shows that our algorithm is able to find decision rules for agents, which in turn can generate the prescribed macro-scale dynamics.
Luo, Linbo; Yin, Haiyan; Cai, Wentong; Lees, Michael; Othman, Nasri Bin; Zhou,; Suiping,
Towards a data-driven approach to scenario generation for serious games Journal Article
In: Computer Animation and Virtual Worlds, 25 (3-4), pp. 395–404, 2014, ISSN: 15464261.
@article{Luo2014,
title = {Towards a data-driven approach to scenario generation for serious games},
author = {Linbo Luo and Haiyan Yin and Wentong Cai and Michael Lees and Nasri Bin Othman and Zhou and Suiping},
url = {http://doi.wiley.com/10.1002/cav.1588},
doi = {10.1002/cav.1588},
issn = {15464261},
year = {2014},
date = {2014-05-01},
journal = {Computer Animation and Virtual Worlds},
volume = {25},
number = {3-4},
pages = {395--404},
abstract = {Serious games have recently shown great potential to be adopted in many applications, such as training and education.However, one critical challenge in developing serious games is the authoring of a large set of scenarios for differenttraining objectives. In this paper, we propose a data-driven approach to automatically generate scenarios for serious games.Compared with other scenario generation methods, our approach leverages on the simulated player performance data toconstruct the scenario evaluation function for scenario generation. To collect the player performance data, an artificialintelligence (AI) player model is designed to imitate how a human player behaves when playing scenarios. The AI playersare used to replace human players for data collection. The experiment results show that our data-driven approach providesgood prediction accuracy on scenarios training intensities. It also outperforms our previous heuristic-based approach in itscapability of generating scenarios that match closer to specified target player performance},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Serious games have recently shown great potential to be adopted in many applications, such as training and education.However, one critical challenge in developing serious games is the authoring of a large set of scenarios for differenttraining objectives. In this paper, we propose a data-driven approach to automatically generate scenarios for serious games.Compared with other scenario generation methods, our approach leverages on the simulated player performance data toconstruct the scenario evaluation function for scenario generation. To collect the player performance data, an artificialintelligence (AI) player model is designed to imitate how a human player behaves when playing scenarios. The AI playersare used to replace human players for data collection. The experiment results show that our data-driven approach providesgood prediction accuracy on scenarios training intensities. It also outperforms our previous heuristic-based approach in itscapability of generating scenarios that match closer to specified target player performance
Viswanathan, Vaisagh; Lee, Chong Eu; Lees, Michael Harold; Cheong, Siew Ann; Sloot, Peter M A
Quantitative comparison between crowd models for evacuation planning and evaluation Journal Article
In: The European Physical Journal B, 87 (2), pp. 27, 2014, ISSN: 1434-6028.
@article{Viswanathan2014,
title = {Quantitative comparison between crowd models for evacuation planning and evaluation},
author = {Vaisagh Viswanathan and Chong Eu Lee and Michael Harold Lees and Siew Ann Cheong and Peter M A Sloot},
url = {http://link.springer.com/10.1140/epjb/e2014-40699-x},
doi = {10.1140/epjb/e2014-40699-x},
issn = {1434-6028},
year = {2014},
date = {2014-02-01},
journal = {The European Physical Journal B},
volume = {87},
number = {2},
pages = {27},
abstract = {Crowd simulation is rapidly becoming a standard tool for evacuation planning and evaluation. However, the many crowd models in the literature are structurally different, and few have been rigorously calibrated against real-world egress data, especially in emergency situations. In this paper we describe a procedure to quantitatively compare different crowd models or between models and real-world data. We simulated three models: (1) the lattice gas model, (2) the social force model, and (3) the RVO2 model, and obtained the distributions of six observables: (1) evacuation time, (2) zoned evacuation time, (3) passage density, (4) total distance traveled, (5) inconvenience, and (6) flow rate. We then used the DISTATIS procedure to compute the compromise matrix of statistical distances between the three models. Projecting the three models onto the first two principal components of the compromise matrix, we find the lattice gas and RVO2 models are similar in terms of the evacuation time, passage density, and flow rates, whereas the social force and RVO2 models are similar in terms of the total distance traveled. Most importantly, we find that the zoned evacuation times of the three models to be very different from each other. Thus we propose to use this variable, if it can be measured, as the key test between different models, and also between models and the real world. Finally, we compared the model flow rates against the flow rate of an emergency evacuation during the May 2008 Sichuan earthquake, and found the social force model agrees best with this real data.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Crowd simulation is rapidly becoming a standard tool for evacuation planning and evaluation. However, the many crowd models in the literature are structurally different, and few have been rigorously calibrated against real-world egress data, especially in emergency situations. In this paper we describe a procedure to quantitatively compare different crowd models or between models and real-world data. We simulated three models: (1) the lattice gas model, (2) the social force model, and (3) the RVO2 model, and obtained the distributions of six observables: (1) evacuation time, (2) zoned evacuation time, (3) passage density, (4) total distance traveled, (5) inconvenience, and (6) flow rate. We then used the DISTATIS procedure to compute the compromise matrix of statistical distances between the three models. Projecting the three models onto the first two principal components of the compromise matrix, we find the lattice gas and RVO2 models are similar in terms of the evacuation time, passage density, and flow rates, whereas the social force and RVO2 models are similar in terms of the total distance traveled. Most importantly, we find that the zoned evacuation times of the three models to be very different from each other. Thus we propose to use this variable, if it can be measured, as the key test between different models, and also between models and the real world. Finally, we compared the model flow rates against the flow rate of an emergency evacuation during the May 2008 Sichuan earthquake, and found the social force model agrees best with this real data.
Xu, Yadong; Cai, Wentong; Aydt, Heiko; Lees, Michael
Efficient Graph-based Dynamic Load-balancing for Parallel Large-scale Agent-based Traffic Simulation Inproceedings
In: Proceedings of the 2014 Winter Simulation Conference, pp. 3483–3494, IEEE Press, Piscataway, NJ, USA, 2014.
@inproceedings{Xu:2014:EGD:2693848.2694282,
title = {Efficient Graph-based Dynamic Load-balancing for Parallel Large-scale Agent-based Traffic Simulation},
author = {Yadong Xu and Wentong Cai and Heiko Aydt and Michael Lees},
url = {http://dl.acm.org/citation.cfm?id=2693848.2694282},
year = {2014},
date = {2014-01-01},
booktitle = {Proceedings of the 2014 Winter Simulation Conference},
pages = {3483--3494},
publisher = {IEEE Press},
address = {Piscataway, NJ, USA},
series = {WSC '14},
abstract = {One of the issues of parallelizing large-scale agent-based traffic simulations is partitioning and load-balancing. Traffic simulations are dynamic applications where the distribution of workload in the spatial domain constantly changes. Dynamic load-balancing at run-time has shown better efficiency than static partitioning in many studies. However, existing work has only focused on geographic partitioning methods which do not consider the minimization of communication overhead. In this paper, a graph-based dynamic load-balancing mechanism which minimizes the communication overhead during load-balancing operations is developed. Its efficiency is investigated in the agent-based traffic simulator SEMSim Traffic using real world traffic data. Experiment results show that it has significantly better performance than static graph partitioning methods in improving the overall speed of the simulation.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
One of the issues of parallelizing large-scale agent-based traffic simulations is partitioning and load-balancing. Traffic simulations are dynamic applications where the distribution of workload in the spatial domain constantly changes. Dynamic load-balancing at run-time has shown better efficiency than static partitioning in many studies. However, existing work has only focused on geographic partitioning methods which do not consider the minimization of communication overhead. In this paper, a graph-based dynamic load-balancing mechanism which minimizes the communication overhead during load-balancing operations is developed. Its efficiency is investigated in the agent-based traffic simulator SEMSim Traffic using real world traffic data. Experiment results show that it has significantly better performance than static graph partitioning methods in improving the overall speed of the simulation.
Angela, Teo Yu Hui; Viswanathan, Vaisagh; Lees, Michael; Cai, Wentong
Analysing the Effectiveness of Wearable Wireless Sensors in Controlling Crowd Disasters Journal Article
In: Procedia Computer Science, 29 , pp. 1590–1599, 2014, ISSN: 18770509.
@article{Angela2014,
title = {Analysing the Effectiveness of Wearable Wireless Sensors in Controlling Crowd Disasters},
author = {Teo Yu Hui Angela and Vaisagh Viswanathan and Michael Lees and Wentong Cai},
url = {http://www.sciencedirect.com/science/article/pii/S1877050914003214},
doi = {10.1016/j.procs.2014.05.144},
issn = {18770509},
year = {2014},
date = {2014-01-01},
journal = {Procedia Computer Science},
volume = {29},
pages = {1590--1599},
abstract = {The Love Parade disaster in Duisberg, Germany lead to several deaths and injuries. Disasters like this occur due to the existence of high densities in a limited area. We propose a wearable electronic device that helps reduce such disasters by directing people and thus controlling the density of the crowd. We investigate the design and effectiveness of such a device through an agent based simulation using social force. We also investigate the effect of device failure and participants not paying attention in order to determine the critical number of devices and attentive participants required for the device to be effective.},
keywords = {},
pubstate = {published},
tppubtype = {article}
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The Love Parade disaster in Duisberg, Germany lead to several deaths and injuries. Disasters like this occur due to the existence of high densities in a limited area. We propose a wearable electronic device that helps reduce such disasters by directing people and thus controlling the density of the crowd. We investigate the design and effectiveness of such a device through an agent based simulation using social force. We also investigate the effect of device failure and participants not paying attention in order to determine the critical number of devices and attentive participants required for the device to be effective.
Wagner, Michael; Cai, Wentong; Lees, Michael H; Aydt, Heiko
Evolving Agent-based Models Using Complexification Approach Journal Article
In: Procedia Computer Science, 29 , pp. 310–321, 2014, ISSN: 18770509.
@article{Wagner2014,
title = {Evolving Agent-based Models Using Complexification Approach},
author = {Michael Wagner and Wentong Cai and Michael H Lees and Heiko Aydt},
url = {http://www.sciencedirect.com/science/article/pii/S1877050914002051},
doi = {10.1016/j.procs.2014.05.028},
issn = {18770509},
year = {2014},
date = {2014-01-01},
journal = {Procedia Computer Science},
volume = {29},
pages = {310--321},
abstract = {This paper focuses on parameter search for multi-agent based models using evolutionary algorithms. Large numbers and variable dimensions of parameters require a search method which can efficiently handle a high dimensional search space. We are proposing the use of complexification as it emulates the natural way of evolution by starting with a small constrained search space and expanding it as the evolution progresses. We examined the effects of this method on an EA by evolving parameters for two multi-agent based models.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper focuses on parameter search for multi-agent based models using evolutionary algorithms. Large numbers and variable dimensions of parameters require a search method which can efficiently handle a high dimensional search space. We are proposing the use of complexification as it emulates the natural way of evolution by starting with a small constrained search space and expanding it as the evolution progresses. We examined the effects of this method on an EA by evolving parameters for two multi-agent based models.
Zhong, Jinghui; Cai, Wentong; Luo, Linbo; Lees, Michael
Ea-based Evacuation Planning Using Agent-based Crowd Simulation Inproceedings
In: Proceedings of the 2014 Winter Simulation Conference, pp. 395–406, IEEE Press, Piscataway, NJ, USA, 2014.
@inproceedings{Zhong:2014:EEP:2693848.2693908,
title = {Ea-based Evacuation Planning Using Agent-based Crowd Simulation},
author = {Jinghui Zhong and Wentong Cai and Linbo Luo and Michael Lees},
url = {http://dl.acm.org/citation.cfm?id=2693848.2693908},
year = {2014},
date = {2014-01-01},
booktitle = {Proceedings of the 2014 Winter Simulation Conference},
pages = {395--406},
publisher = {IEEE Press},
address = {Piscataway, NJ, USA},
series = {WSC '14},
abstract = {Safety planning for crowd evacuation is an important and active research topic nowadays. One important issue is to devise the evacuation plans of individuals in emergency situations so as to reduce the total evacuation time. This paper proposes a novel evolutionary algorithm (EA)-based methodology, together with agent-based crowd simulation, to solve the evacuation planning problem. The proposed method features a novel segmentation strategy which divides the entire evacuation region into sub-regions based on a discriminant function. Each sub-region is assigned with an exit gate, and individuals in a sub-region will run toward the corresponding exit gate for evacuation. In this way, the evacuation planning problem is converted to a symbolic regression problem. Then an evolutionary algorithm, using agent-based crowd simulation as fitness function, is developed to search for the global optimal solution. The simulation results on different scenarios demonstrate that the proposed method is effective to reduce the evacuation time.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Safety planning for crowd evacuation is an important and active research topic nowadays. One important issue is to devise the evacuation plans of individuals in emergency situations so as to reduce the total evacuation time. This paper proposes a novel evolutionary algorithm (EA)-based methodology, together with agent-based crowd simulation, to solve the evacuation planning problem. The proposed method features a novel segmentation strategy which divides the entire evacuation region into sub-regions based on a discriminant function. Each sub-region is assigned with an exit gate, and individuals in a sub-region will run toward the corresponding exit gate for evacuation. In this way, the evacuation planning problem is converted to a symbolic regression problem. Then an evolutionary algorithm, using agent-based crowd simulation as fitness function, is developed to search for the global optimal solution. The simulation results on different scenarios demonstrate that the proposed method is effective to reduce the evacuation time.
Duan, Wei; Quax, Rick; Lees, Michael; Qiu, Xiaogang; Sloot, Peter M A
Topology dependent epidemic spreading velocity in weighted networks Journal Article
In: Journal of Statistical Mechanics: Theory and Experiment, 2014 (12), pp. P12020, 2014.
@article{duan2014topology,
title = {Topology dependent epidemic spreading velocity in weighted networks},
author = {Wei Duan and Rick Quax and Michael Lees and Xiaogang Qiu and Peter M A Sloot},
year = {2014},
date = {2014-01-01},
journal = {Journal of Statistical Mechanics: Theory and Experiment},
volume = {2014},
number = {12},
pages = {P12020},
publisher = {IOP Publishing},
keywords = {},
pubstate = {published},
tppubtype = {article}
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2013
Zehe, Daniel; Aydt, Heiko; Lees, Michael; Knoll, Alois
JavaScript Distributed Agent Based Discrete Event Simulation Inproceedings
In: In proceedings of the The 17th IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications, 2013.
@inproceedings{Zehe2013,
title = {JavaScript Distributed Agent Based Discrete Event Simulation},
author = {Daniel Zehe and Heiko Aydt and Michael Lees and Alois Knoll},
year = {2013},
date = {2013-10-01},
booktitle = {In proceedings of the The 17th IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Hu, Nan; Lees, Michael Harold; Zhou, Suiping
A pattern-based modeling framework for simulating human-like pedestrian steering behaviors Inproceedings
In: Proceedings of the 19th ACM Symposium on Virtual Reality Software and Technology - VRST '13, pp. 179, ACM Press, New York, New York, USA, 2013, ISBN: 9781450323796.
@inproceedings{Hu2013,
title = {A pattern-based modeling framework for simulating human-like pedestrian steering behaviors},
author = {Nan Hu and Michael Harold Lees and Suiping Zhou},
url = {http://dl.acm.org/citation.cfm?id=2503713.2503723},
doi = {10.1145/2503713.2503723},
isbn = {9781450323796},
year = {2013},
date = {2013-10-01},
booktitle = {Proceedings of the 19th ACM Symposium on Virtual Reality Software and Technology - VRST '13},
pages = {179},
publisher = {ACM Press},
address = {New York, New York, USA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Xiao, Jiajian; Aydt, Heiko; Lees, Michael; Knoll, Alois
A Partition Based Match Making Algorithm for Taxi Sharing Inproceedings
In: 16th International IEEE Annual Conference on Intelligent Transportation Systems, 2013.
@inproceedings{JiaJian2013,
title = {A Partition Based Match Making Algorithm for Taxi Sharing},
author = {Jiajian Xiao and Heiko Aydt and Michael Lees and Alois Knoll},
year = {2013},
date = {2013-10-01},
booktitle = {16th International IEEE Annual Conference on Intelligent Transportation Systems},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Luo, Linbo; Yin, Haiyan; Zhong, Jinghui; Cai, Wentong; Lees, Michael; Zhou, Suiping
Mission-based Scenario Modeling and Generation for Virtual Training Inproceedings
In: Proceedings of the Ninth Annual AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment, 2013.
@inproceedings{Linbo2013,
title = {Mission-based Scenario Modeling and Generation for Virtual Training},
author = {Linbo Luo and Haiyan Yin and Jinghui Zhong and Wentong Cai and Michael Lees and Suiping Zhou},
year = {2013},
date = {2013-10-01},
booktitle = {Proceedings of the Ninth Annual AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
ADAMATZKY, ANDREW; LEES, MICHAEL; SLOOT, PETER
BIO-DEVELOPMENT OF MOTORWAY NETWORK IN THE NETHERLANDS: A SLIME MOULD APPROACH Journal Article
In: Advances in Complex Systems, 16 (02n03), pp. 1250034, 2013, ISSN: 0219-5259.
@article{adamatzky2012bio,
title = {BIO-DEVELOPMENT OF MOTORWAY NETWORK IN THE NETHERLANDS: A SLIME MOULD APPROACH},
author = {ANDREW ADAMATZKY and MICHAEL LEES and PETER SLOOT},
url = {http://www.worldscientific.com/doi/abs/10.1142/S0219525912500348},
doi = {10.1142/S0219525912500348},
issn = {0219-5259},
year = {2013},
date = {2013-05-01},
journal = {Advances in Complex Systems},
volume = {16},
number = {02n03},
pages = {1250034},
publisher = {World Scientific Publishing Company},
abstract = {Plasmodium of a cellular slime mould Physarum polycephalum is a very large eukaryotic microbe visible to the unaided eye. During its foraging behavior the plasmodium spans sources of nutrients with a network of protoplasmic tubes. In this paper we attempt to address the following question: Is slime mould capable of computing transport networks? By assuming the sources of nutrients are cities and protoplasmic tubes connecting the sources are motorways, how well does the plasmodium approximate existing motorway networks? We take the Netherlands as a case study for bio-development of motorways, while it has the most dense motorway network in Europe, current demand is rapidly approaching the upper limits of existing capacity. We represent twenty major cities with oat flakes, place plasmodium in Amsterdam and record how the plasmodium spreads between oat flakes via the protoplasmic tubes. First we analyze slime-mould-built and man-built transport networks in a framework of proximity graphs to investigate if the slime mould is capable of computing existing networks. We then go on to investigate if the slime mould is able calculate or adapt the network through imitating restructuring of the transport network as a response to potential localized flooding of the Netherlands. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0219525912500348?journalCode=acs},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Plasmodium of a cellular slime mould Physarum polycephalum is a very large eukaryotic microbe visible to the unaided eye. During its foraging behavior the plasmodium spans sources of nutrients with a network of protoplasmic tubes. In this paper we attempt to address the following question: Is slime mould capable of computing transport networks? By assuming the sources of nutrients are cities and protoplasmic tubes connecting the sources are motorways, how well does the plasmodium approximate existing motorway networks? We take the Netherlands as a case study for bio-development of motorways, while it has the most dense motorway network in Europe, current demand is rapidly approaching the upper limits of existing capacity. We represent twenty major cities with oat flakes, place plasmodium in Amsterdam and record how the plasmodium spreads between oat flakes via the protoplasmic tubes. First we analyze slime-mould-built and man-built transport networks in a framework of proximity graphs to investigate if the slime mould is capable of computing existing networks. We then go on to investigate if the slime mould is able calculate or adapt the network through imitating restructuring of the transport network as a response to potential localized flooding of the Netherlands. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0219525912500348?journalCode=acs
Luo, Linbo; Yin, Haiyan; Cai, Wentong; Lees, Michael; Zhou, Suiping
Interactive scenario generation for mission-based virtual training Journal Article
In: Computer Animation and Virtual Worlds, 24 (3-4), pp. 345–354, 2013, ISSN: 15464261.
@article{Luo2013,
title = {Interactive scenario generation for mission-based virtual training},
author = {Linbo Luo and Haiyan Yin and Wentong Cai and Michael Lees and Suiping Zhou},
url = {http://doi.wiley.com/10.1002/cav.1525},
doi = {10.1002/cav.1525},
issn = {15464261},
year = {2013},
date = {2013-05-01},
journal = {Computer Animation and Virtual Worlds},
volume = {24},
number = {3-4},
pages = {345--354},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Suryanarayanan, Vinoth; Theodoropoulos, Georgios; Lees, Michael
PDES-MAS: Distributed Simulation of Multi-agent Systems Journal Article
In: Procedia Computer Science, 18 , pp. 671–681, 2013.
@article{Suryanarayanan2013,
title = {PDES-MAS: Distributed Simulation of Multi-agent Systems},
author = {Vinoth Suryanarayanan and Georgios Theodoropoulos and Michael Lees},
url = {http://www.sciencedirect.com/science/article/pii/S1877050913003748},
year = {2013},
date = {2013-01-01},
journal = {Procedia Computer Science},
volume = {18},
pages = {671--681},
abstract = {Multi-agent systems (MAS) are increasingly being acknowledged as a modelling paradigm for capturing the dynamics of complex systems in a wide range of domains, from system biology to adaptive socio-technical system of systems. The execution of such MAS simulations on parallel machines is a challenging problem due to their dynamic, non-deterministic, data-centric behaviour and nature. These problems are exacerbated as the scale of such MAS models increases. PDES-MAS is a distributed simulation kernel developed specifically to support MAS models addressing the problems of partitioning, load balancing and interest management in an integrated, transparent and adaptive manner. This paper presents an overview of PDES-MAS and for the first time it provides a quantitative evaluation of the system.},
keywords = {},
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Multi-agent systems (MAS) are increasingly being acknowledged as a modelling paradigm for capturing the dynamics of complex systems in a wide range of domains, from system biology to adaptive socio-technical system of systems. The execution of such MAS simulations on parallel machines is a challenging problem due to their dynamic, non-deterministic, data-centric behaviour and nature. These problems are exacerbated as the scale of such MAS models increases. PDES-MAS is a distributed simulation kernel developed specifically to support MAS models addressing the problems of partitioning, load balancing and interest management in an integrated, transparent and adaptive manner. This paper presents an overview of PDES-MAS and for the first time it provides a quantitative evaluation of the system.
Wagner, Michael; Cai, Wentong; Lees, Michael
Emergence by Strategy: Flocking Boids and their Fitness in Relation to Model Complexity Inproceedings
In: Proceedings of the 2013 Winter Simulation Conference, WSC 2013, Washington D.C., USA, December 8-11, 2013, 2013.
@inproceedings{Wagner13,
title = {Emergence by Strategy: Flocking Boids and their Fitness in Relation to Model Complexity},
author = {Michael Wagner and Wentong Cai and Michael Lees},
year = {2013},
date = {2013-01-01},
booktitle = {Proceedings of the 2013 Winter Simulation Conference, WSC 2013, Washington D.C., USA, December 8-11, 2013},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Othman, Nasri Bin; Luo, Linbo; Cai, Wentong; Lees, Michael
Spatial indexing in agent-based crowd simulation Inproceedings
In: SimuTools '13 Proceedings of the 6th International ICST Conference on Simulation Tools and Techniques, pp. 92–100, ICST (Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering), 2013, ISBN: 978-1-4503-2464-9.
@inproceedings{Othman2013,
title = {Spatial indexing in agent-based crowd simulation},
author = {Nasri Bin Othman and Linbo Luo and Wentong Cai and Michael Lees},
url = {http://dl.acm.org/citation.cfm?id=2512734.2512746},
isbn = {978-1-4503-2464-9},
year = {2013},
date = {2013-01-01},
booktitle = {SimuTools '13 Proceedings of the 6th International ICST Conference on Simulation Tools and Techniques},
pages = {92--100},
publisher = {ICST (Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Aydt, Heiko; Xu, Yadong; Lees, Michael; Knoll, Alois
A Multi-Threaded Execution Model for the Agent-based SEMSim Traffic Simulation Inproceedings
In: Proceedings of the 13th International Conference on Systems Simulation (AsiaSim), pp. 1––12, Springer Berlin Heidelberg, 2013.
@inproceedings{Aydt13,
title = {A Multi-Threaded Execution Model for the Agent-based SEMSim Traffic Simulation},
author = {Heiko Aydt and Yadong Xu and Michael Lees and Alois Knoll},
url = {http://link.springer.com/chapter/10.1007%2F978-3-642-45037-2_1#},
doi = {10.1007/978-3-642-45037-2_1},
year = {2013},
date = {2013-01-01},
booktitle = {Proceedings of the 13th International Conference on Systems Simulation (AsiaSim)},
pages = {1----12},
publisher = {Springer Berlin Heidelberg},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2012
Zhang, Tianyou; Lees, Michael; Kwoh, Chee Keong; Fu, Xuju; Lee, Gary Kee Khoon; Goh, Rick Siow Mong
A contact-network-based simulation model for evaluating interventions under what-if scenarios in epidemic Inproceedings
In: Proceedings Title: Proceedings of the 2012 Winter Simulation Conference (WSC), pp. 1–12, Winter Simulation Conference IEEE, 2012, ISBN: 978-1-4673-4782-2.
@inproceedings{zhang2012contact,
title = {A contact-network-based simulation model for evaluating interventions under what-if scenarios in epidemic},
author = {Tianyou Zhang and Michael Lees and Chee Keong Kwoh and Xuju Fu and Gary Kee Khoon Lee and Rick Siow Mong Goh},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6465056},
doi = {10.1109/WSC.2012.6465056},
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Aydt, Heiko; Lees, Michael; Knoll, Alois
Symbiotic simulation for future electro-mobility transportation systems Inproceedings
In: Proceedings Title: Proceedings of the 2012 Winter Simulation Conference (WSC), pp. 1–12, Winter Simulation Conference IEEE, 2012, ISBN: 978-1-4673-4782-2.
@inproceedings{aydt2012symbiotic,
title = {Symbiotic simulation for future electro-mobility transportation systems},
author = {Heiko Aydt and Michael Lees and Alois Knoll},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6465312},
doi = {10.1109/WSC.2012.6465312},
isbn = {978-1-4673-4782-2},
year = {2012},
date = {2012-12-01},
booktitle = {Proceedings Title: Proceedings of the 2012 Winter Simulation Conference (WSC)},
pages = {1--12},
publisher = {IEEE},
organization = {Winter Simulation Conference},
abstract = {Electro-mobility is widely regarded as the future of transportation systems. The shift from fossil fuel-based engines to electro-mobility will pose new challenges to the operations of future transportation systems. Our vision of a smart transportation system for the future entails a collaborative communication and simulation infrastructure that can help to mitigate common traffic-related problems as well as problems that are specific to electric vehicles. At the core of this smart transportation system would be a symbiotic simulation system which incorporates information provided by the various traffic participants into city-scale traffic simulations. We describe the symbiotic simulation system and highlight the research challenges that need to be addressed in order to realize such a system. This includes a server-based city-scale simulation which would forecast general traffic patterns and conditions in the near-future. The outcome of these simulations can be used by server-based smart routing services and/or in-car navigation systems.},
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Electro-mobility is widely regarded as the future of transportation systems. The shift from fossil fuel-based engines to electro-mobility will pose new challenges to the operations of future transportation systems. Our vision of a smart transportation system for the future entails a collaborative communication and simulation infrastructure that can help to mitigate common traffic-related problems as well as problems that are specific to electric vehicles. At the core of this smart transportation system would be a symbiotic simulation system which incorporates information provided by the various traffic participants into city-scale traffic simulations. We describe the symbiotic simulation system and highlight the research challenges that need to be addressed in order to realize such a system. This includes a server-based city-scale simulation which would forecast general traffic patterns and conditions in the near-future. The outcome of these simulations can be used by server-based smart routing services and/or in-car navigation systems.
Wang, Yongwei; Lees, Michael; Cai, Wentong
Grid-based partitioning for large-scale distributed agent-based crowd simulation Inproceedings
In: Proceedings Title: Proceedings of the 2012 Winter Simulation Conference (WSC), pp. 1–12, Winter Simulation Conference IEEE, 2012, ISBN: 978-1-4673-4782-2.
@inproceedings{wang2012grid,
title = {Grid-based partitioning for large-scale distributed agent-based crowd simulation},
author = {Yongwei Wang and Michael Lees and Wentong Cai},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6465161},
doi = {10.1109/WSC.2012.6465161},
isbn = {978-1-4673-4782-2},
year = {2012},
date = {2012-12-01},
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}
Fozard, J A; Lees, M; King, J R; Logan, B S
Inhibition of quorum sensing in a computational biofilm simulation. Journal Article
In: Bio Systems, 109 (2), pp. 105–14, 2012, ISSN: 1872-8324.
@article{fozard2012inhibition,
title = {Inhibition of quorum sensing in a computational biofilm simulation.},
author = {J A Fozard and M Lees and J R King and B S Logan},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22374433},
doi = {10.1016/j.biosystems.2012.02.002},
issn = {1872-8324},
year = {2012},
date = {2012-08-01},
journal = {Bio Systems},
volume = {109},
number = {2},
pages = {105--14},
abstract = {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 for computational efficiency, but the quorum-sensing mechanism is modelled as a stochastic process on the level of individual cells. Simulations are used to investigate different treatment regimens. The response to the addition of inhibitor is found to depend significantly on the form of the positive feedback in the quorum-sensing model; in cases where the model exhibits bistability, the time at which treatment is initiated proves to be critical for the effective prevention of quorum sensing and hence potentially of virulence.},
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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 for computational efficiency, but the quorum-sensing mechanism is modelled as a stochastic process on the level of individual cells. Simulations are used to investigate different treatment regimens. The response to the addition of inhibitor is found to depend significantly on the form of the positive feedback in the quorum-sensing model; in cases where the model exhibits bistability, the time at which treatment is initiated proves to be critical for the effective prevention of quorum sensing and hence potentially of virulence.
Xu, Yadong; Aydt, Heiko; Lees, Michael
SEMSim: A Distributed Architecture for Multi-scale Traffic Simulation Inproceedings
In: 2012 ACM/IEEE/SCS 26th Workshop on Principles of Advanced and Distributed Simulation, pp. 178–180, IEEE Computer Society IEEE, 2012, ISBN: 978-1-4673-1797-9.
@inproceedings{xu2012semsim,
title = {SEMSim: A Distributed Architecture for Multi-scale Traffic Simulation},
author = {Yadong Xu and Heiko Aydt and Michael Lees},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6305906},
doi = {10.1109/PADS.2012.40},
isbn = {978-1-4673-1797-9},
year = {2012},
date = {2012-07-01},
booktitle = {2012 ACM/IEEE/SCS 26th Workshop on Principles of Advanced and Distributed Simulation},
pages = {178--180},
publisher = {IEEE},
organization = {IEEE Computer Society},
abstract = {With the fast urbanization of our modern society, transportation systems in cities are facing increasing problems such as congestion, collisions, and high levels of emissions. Researchers have been searching for solutions by investigating better urban planning and transportation policies, introducing new technologies such as Intelligent Transportation System (ITS), or introducing more environmentally friendly vehicles such as electric vehicles (EVs). Traffic modeling and simulation is one tool adopted by researchers for more than half a century [to help authorities assess new infrastructure design, and new policies without impacting real traffic. City-scale nanoscopic traffic simulation is a challenging problem that requires parallelization and distribution. In this paper, we have given an overview of the architecture for our nanoscopic traffic simulator SEMSim. For efficient parallel simulation, reducing the dependencies between the various LPs is crucial. We have specified a multi-objective optimization problem concerned with the allocation of agents to clusters. In our future work, we will implement a nanoscopic traffic simulation and devise methods to solve this problem dynamically. Given the difficulty of the problem, these methods will have to make use of domain-specific knowledge, such as information about the topology of the road network.},
keywords = {},
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With the fast urbanization of our modern society, transportation systems in cities are facing increasing problems such as congestion, collisions, and high levels of emissions. Researchers have been searching for solutions by investigating better urban planning and transportation policies, introducing new technologies such as Intelligent Transportation System (ITS), or introducing more environmentally friendly vehicles such as electric vehicles (EVs). Traffic modeling and simulation is one tool adopted by researchers for more than half a century [to help authorities assess new infrastructure design, and new policies without impacting real traffic. City-scale nanoscopic traffic simulation is a challenging problem that requires parallelization and distribution. In this paper, we have given an overview of the architecture for our nanoscopic traffic simulator SEMSim. For efficient parallel simulation, reducing the dependencies between the various LPs is crucial. We have specified a multi-objective optimization problem concerned with the allocation of agents to clusters. In our future work, we will implement a nanoscopic traffic simulation and devise methods to solve this problem dynamically. Given the difficulty of the problem, these methods will have to make use of domain-specific knowledge, such as information about the topology of the road network.
Adamatzky, A; Lees, M H; Sloot, P M A
Physarum in the Netherlands: Responding to the Flood Book Chapter
In: Adamatzky, A (Ed.): Bioevaluation of World Transport Networks, pp. 1–380, World Scientific, 2012.
@inbook{Adamatzky2012c,
title = {Physarum in the Netherlands: Responding to the Flood},
author = {A Adamatzky and M H Lees and P M A Sloot},
editor = {A Adamatzky},
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year = {2012},
date = {2012-01-01},
booktitle = {Bioevaluation of World Transport Networks},
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Zhang, Tianyou; Fu, Xiuju; Ma, Stefan; Xiao, Gaoxi; Wong, Limsoon; Kwoh, Chee Keong; Lees, Michael; Lee, Gary Kee Khoon; Hung, Terence
Evaluating temporal factors in combined interventions of workforce shift and school closure for mitigating the spread of influenza. Journal Article
In: PloS one, 7 (3), pp. e32203, 2012, ISSN: 1932-6203.
@article{zhang2012evaluating,
title = {Evaluating temporal factors in combined interventions of workforce shift and school closure for mitigating the spread of influenza.},
author = {Tianyou Zhang and Xiuju Fu and Stefan Ma and Gaoxi Xiao and Limsoon Wong and Chee Keong Kwoh and Michael Lees and Gary Kee Khoon Lee and Terence Hung},
url = {http://dx.plos.org/10.1371/journal.pone.0032203 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3293885&tool=pmcentrez&rendertype=abstract},
doi = {10.1371/journal.pone.0032203},
issn = {1932-6203},
year = {2012},
date = {2012-01-01},
journal = {PloS one},
volume = {7},
number = {3},
pages = {e32203},
publisher = {Public Library of Science},
abstract = {BACKGROUND: It is believed that combined interventions may be more effective than individual interventions in mitigating epidemic. However there is a lack of quantitative studies on performance of the combination of individual interventions under different temporal settings. METHODOLOGY/PRINCIPAL FINDINGS: To better understand the problem, we develop an individual-based simulation model running on top of contact networks based on real-life contact data in Singapore. We model and evaluate the spread of influenza epidemic with intervention strategies of workforce shift and its combination with school closure, and examine the impacts of temporal factors, namely the trigger threshold and the duration of an intervention. By comparing simulation results for intervention scenarios with different temporal factors, we find that combined interventions do not always outperform individual interventions and are more effective only when the duration is longer than 6 weeks or school closure is triggered at the 5% threshold; combined interventions may be more effective if school closure starts first when the duration is less than 4 weeks or workforce shift starts first when the duration is longer than 4 weeks. CONCLUSIONS/SIGNIFICANCE: We therefore conclude that identifying the appropriate timing configuration is crucial for achieving optimal or near optimal performance in mitigating the spread of influenza epidemic. The results of this study are useful to policy makers in deliberating and planning individual and combined interventions.},
keywords = {},
pubstate = {published},
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}
BACKGROUND: It is believed that combined interventions may be more effective than individual interventions in mitigating epidemic. However there is a lack of quantitative studies on performance of the combination of individual interventions under different temporal settings. METHODOLOGY/PRINCIPAL FINDINGS: To better understand the problem, we develop an individual-based simulation model running on top of contact networks based on real-life contact data in Singapore. We model and evaluate the spread of influenza epidemic with intervention strategies of workforce shift and its combination with school closure, and examine the impacts of temporal factors, namely the trigger threshold and the duration of an intervention. By comparing simulation results for intervention scenarios with different temporal factors, we find that combined interventions do not always outperform individual interventions and are more effective only when the duration is longer than 6 weeks or school closure is triggered at the 5% threshold; combined interventions may be more effective if school closure starts first when the duration is less than 4 weeks or workforce shift starts first when the duration is longer than 4 weeks. CONCLUSIONS/SIGNIFICANCE: We therefore conclude that identifying the appropriate timing configuration is crucial for achieving optimal or near optimal performance in mitigating the spread of influenza epidemic. The results of this study are useful to policy makers in deliberating and planning individual and combined interventions.
Aydt, Heiko; Lees, Michael; Turner, Stephen J; Cai, Wentong
Toward Simulation-based Egress Optimisation in Smart Buildings using Symbiotic Simulation Inproceedings
In: Pedestrian Evacuation Dynamics, 2012.
@inproceedings{Aydt12,
title = {Toward Simulation-based Egress Optimisation in Smart Buildings using Symbiotic Simulation},
author = {Heiko Aydt and Michael Lees and Stephen J Turner and Wentong Cai},
year = {2012},
date = {2012-01-01},
booktitle = {Pedestrian Evacuation Dynamics},
keywords = {},
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tppubtype = {inproceedings}
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Xing, Pengfei; Lees, Michael; Nan, Hu; Viswanthatn, T
Validation of Agent-Based Simulation through Human Computation: An Example of Crowd Simulation Inproceedings
In: Multi-Agent-Based Simulation XII, pp. 90–102, Springer Berlin/Heidelberg, 2012.
@inproceedings{xing2012validation,
title = {Validation of Agent-Based Simulation through Human Computation: An Example of Crowd Simulation},
author = {Pengfei Xing and Michael Lees and Hu Nan and T Viswanthatn},
url = {http://www.springerlink.com/index/041016J828268762.pdf},
doi = {10.1007/978-3-642-28400-7_7},
year = {2012},
date = {2012-01-01},
booktitle = {Multi-Agent-Based Simulation XII},
pages = {90--102},
publisher = {Springer Berlin/Heidelberg},
keywords = {},
pubstate = {published},
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Viswanathan, Vaisagh; Lees, Michael
An Information-Based Model of Pre-evacuation Behavior for Agent Based Egress Simulation Inproceedings
In: Pedestrian Evacuation Dynamics, 2012.
@inproceedings{vasaigh2012ped,
title = {An Information-Based Model of Pre-evacuation Behavior for Agent Based Egress Simulation},
author = {Vaisagh Viswanathan and Michael Lees},
year = {2012},
date = {2012-01-01},
booktitle = {Pedestrian Evacuation Dynamics},
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Mordvintsev, Alexander; Krzhizhanovskaya, Valeria; Lees, Michael; Sloot., Peter
Simulation of City Evacuation Coupled to Flood Dynamics Inproceedings
In: Pedestrian Evacuation Dynamics, 2012.
@inproceedings{Mordvintsev12,
title = {Simulation of City Evacuation Coupled to Flood Dynamics},
author = {Alexander Mordvintsev and Valeria Krzhizhanovskaya and Michael Lees and Peter Sloot.},
year = {2012},
date = {2012-01-01},
booktitle = {Pedestrian Evacuation Dynamics},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Viswanathan, Vaisagh; Lees, Michael
Modeling and Analyzing the Human Cognitive Limits for Perception in Crowd Simulation Inproceedings
In: Transactions on Computational Science XVI, pp. 55–76, Springer Berlin Heidelberg, 2012.
@inproceedings{viswanathan2012modeling,
title = {Modeling and Analyzing the Human Cognitive Limits for Perception in Crowd Simulation},
author = {Vaisagh Viswanathan and Michael Lees},
doi = {10.1007/978-3-642-32663-9_4},
year = {2012},
date = {2012-01-01},
booktitle = {Transactions on Computational Science XVI},
pages = {55--76},
publisher = {Springer Berlin Heidelberg},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Mauro, M Di; Lees, M; Megawati, K; Huang, Z
Pedestrian-vehicles interaction during evacuation Inproceedings
In: Pedestrian Evacuation Dynamics, 2012.
@inproceedings{dimauro12,
title = {Pedestrian-vehicles interaction during evacuation},
author = {M {Di Mauro} and M Lees and K Megawati and Z Huang},
year = {2012},
date = {2012-01-01},
booktitle = {Pedestrian Evacuation Dynamics},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2011
T., Vaisagh Viswanathan; Lees, Michael
An Information-Based Perception Model for Agent-Based Crowd and Egress Simulation Inproceedings
In: 2011 International Conference on Cyberworlds, pp. 38–45, IEEE IEEE, 2011, ISBN: 978-1-4577-1453-5.
@inproceedings{lees2011information,
title = {An Information-Based Perception Model for Agent-Based Crowd and Egress Simulation},
author = {Vaisagh Viswanathan T. and Michael Lees},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6079344},
doi = {10.1109/CW.2011.10},
isbn = {978-1-4577-1453-5},
year = {2011},
date = {2011-10-01},
booktitle = {2011 International Conference on Cyberworlds},
pages = {38--45},
publisher = {IEEE},
organization = {IEEE},
abstract = {One of the major components of Agent Based Crowd Simulation is motion planning. There have been various motion planning algorithms developed and they've become increasingly better and more efficient at calculating the most optimal path. We believe that this optimality is coming at the price of realism. Certain factors like social norms, limitations to human computation capabilities, etc. prevent humans from following their optimal path. One aspect of natural movement is related to perception and the manner in which humans process information. In this paper we propose two additions to generalmotion planning algorithms: (1) Group sensing for motion planning which results in agents avoiding clusters of other agents when choosing their collision free path. (2) Filtering of percepts based on interestingness to model limited information processing capabilities of human beings.},
keywords = {},
pubstate = {published},
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One of the major components of Agent Based Crowd Simulation is motion planning. There have been various motion planning algorithms developed and they've become increasingly better and more efficient at calculating the most optimal path. We believe that this optimality is coming at the price of realism. Certain factors like social norms, limitations to human computation capabilities, etc. prevent humans from following their optimal path. One aspect of natural movement is related to perception and the manner in which humans process information. In this paper we propose two additions to generalmotion planning algorithms: (1) Group sensing for motion planning which results in agents avoiding clusters of other agents when choosing their collision free path. (2) Filtering of percepts based on interestingness to model limited information processing capabilities of human beings.
Stevens, D; Power, H; Lees, M; Morvan, H
A local hermitian RBF meshless numerical method for the solution of multi-zone problems Journal Article
In: Numerical Methods for Partial Differential Equations, 27 (5), pp. 1201–1230, 2011, ISSN: 0749159X.
@article{stevens2011local,
title = {A local hermitian RBF meshless numerical method for the solution of multi-zone problems},
author = {D Stevens and H Power and M Lees and H Morvan},
url = {http://doi.wiley.com/10.1002/num.20577},
doi = {10.1002/num.20577},
issn = {0749159X},
year = {2011},
date = {2011-09-01},
journal = {Numerical Methods for Partial Differential Equations},
volume = {27},
number = {5},
pages = {1201--1230},
publisher = {Wiley Subscription Services, Inc., A Wiley Company},
keywords = {},
pubstate = {published},
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Aydt, Heiko; Lees, Michael; Luo, Linbo; Cai, Wentong; Low, Malcolm Yoke Hean; Kadirvelen, Sornum Kabilen
A Computational Model of Emotions for Agent-Based Crowds in Serious Games Inproceedings
In: 2011 IEEE/WIC/ACM International Conferences on Web Intelligence and Intelligent Agent Technology, pp. 72–80, IEEE IEEE, 2011, ISBN: 978-1-4577-1373-6.
@inproceedings{aydt2011computational,
title = {A Computational Model of Emotions for Agent-Based Crowds in Serious Games},
author = {Heiko Aydt and Michael Lees and Linbo Luo and Wentong Cai and Malcolm Yoke Hean Low and Sornum Kabilen Kadirvelen},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6040757},
doi = {10.1109/WI-IAT.2011.154},
isbn = {978-1-4577-1373-6},
year = {2011},
date = {2011-08-01},
booktitle = {2011 IEEE/WIC/ACM International Conferences on Web Intelligence and Intelligent Agent Technology},
volume = {2},
pages = {72--80},
publisher = {IEEE},
organization = {IEEE},
abstract = {Crowd behaviour is an interesting social phenomenon that emerges from complex interactions of individuals. An important aspect of individual behaviour is emotion which plays a significant role in all aspects of human decision making. For example, heightened emotional states can lead people to take highly unexpected or irrational actions. One popular motivation for simulation of virtual crowds is to generate believable characters in movies and computer games. Recently the concept of serious games has been introduced in both academic and industrial circles. In this paper, we propose an emotion engine, based on modern appraisal theory, that is able to model various emotional crowd characteristics. This appraisal engine is capable of capturing the dynamics of emotional contagion and we show how different crowd composition can lead to different patterns of emotional contagion. In addition, we describe a serious game designed for training military personnel in peaceful crowd control. We evaluate this engine in the context of a property protection protest scenario where the players or soldiers are tasked to maintain a peaceful protest without violence. A systematic evaluation is presented which supports the facial validity of the emotion engine and our model of emotional contagion.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Crowd behaviour is an interesting social phenomenon that emerges from complex interactions of individuals. An important aspect of individual behaviour is emotion which plays a significant role in all aspects of human decision making. For example, heightened emotional states can lead people to take highly unexpected or irrational actions. One popular motivation for simulation of virtual crowds is to generate believable characters in movies and computer games. Recently the concept of serious games has been introduced in both academic and industrial circles. In this paper, we propose an emotion engine, based on modern appraisal theory, that is able to model various emotional crowd characteristics. This appraisal engine is capable of capturing the dynamics of emotional contagion and we show how different crowd composition can lead to different patterns of emotional contagion. In addition, we describe a serious game designed for training military personnel in peaceful crowd control. We evaluate this engine in the context of a property protection protest scenario where the players or soldiers are tasked to maintain a peaceful protest without violence. A systematic evaluation is presented which supports the facial validity of the emotion engine and our model of emotional contagion.
Zhang, Tianyou; Fu, Xiuju; Kwoh, Chee Keong; Xiao, Gaoxi; Wong, Limsoon; Ma, Stefan; Soh, Harold; Lee, Gary Kee Khoon; Hung, Terence; Lees, Michael
Temporal factors in school closure policy for mitigating the spread of influenza. Journal Article
In: Journal of public health policy, 32 (2), pp. 180–97, 2011, ISSN: 1745-655X.
@article{Zhang:May2011,
title = {Temporal factors in school closure policy for mitigating the spread of influenza.},
author = {Tianyou Zhang and Xiuju Fu and Chee Keong Kwoh and Gaoxi Xiao and Limsoon Wong and Stefan Ma and Harold Soh and Gary Kee Khoon Lee and Terence Hung and Michael Lees},
url = {http://www.ingentaconnect.com/content/pal/jphp/2011/00000032/00000002/art00005 http://www.ncbi.nlm.nih.gov/pubmed/21326332},
doi = {10.1057/jphp.2011.1},
issn = {1745-655X},
year = {2011},
date = {2011-05-01},
journal = {Journal of public health policy},
volume = {32},
number = {2},
pages = {180--97},
abstract = {Is school closure effective in mitigating influenza outbreaks? For Singapore, we developed an individual-based simulation model using real-life contact data. We evaluated the impacts of temporal factors - trigger threshold and duration - on the effectiveness of school closure as a mitigation policy. We found an upper bound of the duration of school closure, where further extension beyond which will not bring additional benefits to suppressing the attack rate and peak incidence. For school closure with a relatively short duration (< 6 weeks), it is more effective to start closure after a relatively longer delay from the first day of infection; if the duration of school closure is long (>6 weeks), however, it is better to start it as early as reasonable. Our studies reveal the critical importance of timing in school closure, especially in cost-cautious situations. Our studies also demonstrate the great potential of a properly developed individual-based simulation model in evaluating various disease control policies.},
keywords = {},
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Is school closure effective in mitigating influenza outbreaks? For Singapore, we developed an individual-based simulation model using real-life contact data. We evaluated the impacts of temporal factors - trigger threshold and duration - on the effectiveness of school closure as a mitigation policy. We found an upper bound of the duration of school closure, where further extension beyond which will not bring additional benefits to suppressing the attack rate and peak incidence. For school closure with a relatively short duration (< 6 weeks), it is more effective to start closure after a relatively longer delay from the first day of infection; if the duration of school closure is long (>6 weeks), however, it is better to start it as early as reasonable. Our studies reveal the critical importance of timing in school closure, especially in cost-cautious situations. Our studies also demonstrate the great potential of a properly developed individual-based simulation model in evaluating various disease control policies.
Hu, N; Lees, M; Zhou, S; T, V Viswanathan
Pattern based motion for crowd simulation Inproceedings
In: Transactions on edutainment VI, pp. 99–110, Springer, 2011.
@inproceedings{hu2011pattern,
title = {Pattern based motion for crowd simulation},
author = {N Hu and M Lees and S Zhou and V {Viswanathan T}},
doi = {10.1007/978-3-642-22639-7_11},
year = {2011},
date = {2011-01-01},
booktitle = {Transactions on edutainment VI},
pages = {99--110},
publisher = {Springer},
abstract = {We present a pattern-based approach for simulating the steering behaviour of pedestrians, which aims to imitate the way that real pedestrians perceive spatial-temporal information and make steering decisions in daily-life situations. Novel representations of spatial-temporal patterns are proposed that allow modellers to intuitively and naturally specify some prototypical patterns for various steering behaviours. Based on the spatial-temporal patterns, a hierarchical pattern matching process has been developed, which simulates how pedestrians process spatial temporal information and make steering decisions. Experimental results show that this new approach is quite promising and capable of producing human-like steering. We hope that the idea presented in this paper can direct researchers in this area with a fresh perspective.},
keywords = {},
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We present a pattern-based approach for simulating the steering behaviour of pedestrians, which aims to imitate the way that real pedestrians perceive spatial-temporal information and make steering decisions in daily-life situations. Novel representations of spatial-temporal patterns are proposed that allow modellers to intuitively and naturally specify some prototypical patterns for various steering behaviours. Based on the spatial-temporal patterns, a hierarchical pattern matching process has been developed, which simulates how pedestrians process spatial temporal information and make steering decisions. Experimental results show that this new approach is quite promising and capable of producing human-like steering. We hope that the idea presented in this paper can direct researchers in this area with a fresh perspective.
Luo, Linbo; Zhou, Suiping; Cai, Wentong; Lees, Michael; Low, Malcolm Yoke Hean; Sornum, Kabilen
HumDPM: A Decision Process Model for Modeling Human-like Behaviors in Time- critical and Uncertain Situation Inproceedings
In: Tan, Kenneth C J Gavrilova Marina; (Ed.): Transactions on Computational Science XII, pp. 260, springer, 2011.
@inproceedings{Luo//:11a,
title = {HumDPM: A Decision Process Model for Modeling Human-like Behaviors in Time- critical and Uncertain Situation},
author = {Linbo Luo and Suiping Zhou and Wentong Cai and Michael Lees and Malcolm Yoke Hean Low and Kabilen Sornum},
editor = {Kenneth C J {Gavrilova Marina; Tan}},
url = {http://link.springer.com/chapter/10.1007%2F978-3-642-22336-5_11},
doi = {10.1007/978-3-642-22336-5_11},
year = {2011},
date = {2011-01-01},
booktitle = {Transactions on Computational Science XII},
volume = {6670},
number = {1},
pages = {260},
publisher = {springer},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Orsini, P; Power, H; Lees, M
The Hermite radial basis function control volume method for multi-zones problems; A non-overlapping domain decomposition algorithm Journal Article
In: Computer Methods in Applied Mechanics and Engineering, 200 (5-8), pp. 477–493, 2011, ISSN: 0045-7825.
@article{Orsini2011477,
title = {The Hermite radial basis function control volume method for multi-zones problems; A non-overlapping domain decomposition algorithm},
author = {P Orsini and H Power and M Lees},
url = {http://www.sciencedirect.com/science/article/pii/S004578251000143X},
doi = {10.1016/j.cma.2010.05.001},
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2010
Tran, Hoai Nam Le; Sornum, Kabilen; Seah, Hock Soon; Cai, Wentong; Low, Malcolm Yoke Hean; Zhou, Suiping; Lees, Michael
A systematic approach for rapid 3D reconstruction from photosets Inproceedings
In: 2010 11th International Conference on Control Automation Robotics & Vision, pp. 1167–1174, IEEE, 2010, ISBN: 978-1-4244-7814-9.
@inproceedings{DBLP:conf/icarcv/TranSSCLZL10,
title = {A systematic approach for rapid 3D reconstruction from photosets},
author = {Hoai Nam {Le Tran} and Kabilen Sornum and Hock Soon Seah and Wentong Cai and Malcolm Yoke Hean Low and Suiping Zhou and Michael Lees},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5707388},
doi = {10.1109/ICARCV.2010.5707388},
isbn = {978-1-4244-7814-9},
year = {2010},
date = {2010-12-01},
booktitle = {2010 11th International Conference on Control Automation Robotics & Vision},
pages = {1167--1174},
publisher = {IEEE},
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Luo, Linbo; Zhou, Suiping; Cai, Wentong; Lees, Michael; Low, Malcolm Yoke Hean
Modeling Human-Like Decision Making for Virtual Agents in Time-Critical Situations Inproceedings
In: 2010 International Conference on Cyberworlds, pp. 360–367, IEEE, 2010, ISBN: 978-1-4244-8301-3.
@inproceedings{5655146,
title = {Modeling Human-Like Decision Making for Virtual Agents in Time-Critical Situations},
author = {Linbo Luo and Suiping Zhou and Wentong Cai and Michael Lees and Malcolm Yoke Hean Low},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5655146},
doi = {10.1109/CW.2010.61},
isbn = {978-1-4244-8301-3},
year = {2010},
date = {2010-10-01},
booktitle = {2010 International Conference on Cyberworlds},
pages = {360--367},
publisher = {IEEE},
abstract = {Generating human-like behaviors for virtual agents has become increasingly important in many applications, such as crowd simulation, virtual training, digital entertainment, and safety planning. One of challenging issues in behavior modeling is how virtual agents make decisions given some time-critical and uncertain situations. In this paper, we present HumDPM, a decision process model for virtual agents, which incorporates two important factors of human decision making in time-critical situations: experience and emotion. In HumDPM, rather than relying on deliberate rational analysis, an agent makes its decisions by matching past experience cases to the current situation. We propose the detailed representation of experience case and investigate the mechanisms of situation assessment, experience matching and experience execution. To incorporate emotion into HumDPM, we introduce an emotion appraisal process in situation assessment for emotion elicitation. In HumDPM, the decision making process of an agent may be affected by its emotional states when: 1) deciding whether it is necessary to do a re-match of experience cases, 2) determining the situational context, and 3) selecting experience cases. We illustrate the effectiveness of HumDPM in crowd simulation. A case study for emergency evacuation in a subway station scenario is conducted, which shows how a varied crowd composition leads to different evacuation behaviors, due to the retrieval of different experiences and the variation of agents' emotional states.},
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Generating human-like behaviors for virtual agents has become increasingly important in many applications, such as crowd simulation, virtual training, digital entertainment, and safety planning. One of challenging issues in behavior modeling is how virtual agents make decisions given some time-critical and uncertain situations. In this paper, we present HumDPM, a decision process model for virtual agents, which incorporates two important factors of human decision making in time-critical situations: experience and emotion. In HumDPM, rather than relying on deliberate rational analysis, an agent makes its decisions by matching past experience cases to the current situation. We propose the detailed representation of experience case and investigate the mechanisms of situation assessment, experience matching and experience execution. To incorporate emotion into HumDPM, we introduce an emotion appraisal process in situation assessment for emotion elicitation. In HumDPM, the decision making process of an agent may be affected by its emotional states when: 1) deciding whether it is necessary to do a re-match of experience cases, 2) determining the situational context, and 3) selecting experience cases. We illustrate the effectiveness of HumDPM in crowd simulation. A case study for emergency evacuation in a subway station scenario is conducted, which shows how a varied crowd composition leads to different evacuation behaviors, due to the retrieval of different experiences and the variation of agents' emotional states.
Xiong, Muzhou; Lees, Michael; Cai, Wentong; Zhou, Suiping; Low, Malcolm Yoke Hean
Hybrid modelling of crowd simulation Journal Article
In: Procedia Computer Science, 1 (1), pp. 57–65, 2010.
@article{DBLP:journals/procedia/XiongLCZL10,
title = {Hybrid modelling of crowd simulation},
author = {Muzhou Xiong and Michael Lees and Wentong Cai and Suiping Zhou and Malcolm Yoke Hean Low},
url = {http://linkinghub.elsevier.com/retrieve/pii/S1877050910000098},
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abstract = {Macroscopic and microscopic modeling have become mainstream methodologies for crowd simulation in dynamic environments. The two models make a trade-off between efficiency and accuracy, but neither of them is able to achieve both goals at the same time. With the aim of achieving both efficiency and accuracy, a hybrid modelling method is proposed in this paper for crowd simulation. This paper illustrates how the two types of models co-exist in a single simulation and work collaboratively. A case study for this method is also conducted, the simulation result of which shows that the proposed method can not only benefit from the macroscopic model by improving the simulation efficiency, but also obtain a fine-grained simulation result by adopting the microscopic model.},
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Macroscopic and microscopic modeling have become mainstream methodologies for crowd simulation in dynamic environments. The two models make a trade-off between efficiency and accuracy, but neither of them is able to achieve both goals at the same time. With the aim of achieving both efficiency and accuracy, a hybrid modelling method is proposed in this paper for crowd simulation. This paper illustrates how the two types of models co-exist in a single simulation and work collaboratively. A case study for this method is also conducted, the simulation result of which shows that the proposed method can not only benefit from the macroscopic model by improving the simulation efficiency, but also obtain a fine-grained simulation result by adopting the microscopic model.
Chen, Dan; Turner, Stephen John; Cai, Wentong; Theodoropoulos, Georgios K; Xiong, Muzhou; Lees, Michael
Synchronization in federation community networks Journal Article
In: Journal of Parallel and Distributed Computing, 70 (2), pp. 144–159, 2010.
@article{DBLP:journals/jpdc/ChenTCTXL10,
title = {Synchronization in federation community networks},
author = {Dan Chen and Stephen John Turner and Wentong Cai and Georgios K Theodoropoulos and Muzhou Xiong and Michael Lees},
url = {http://linkinghub.elsevier.com/retrieve/pii/S074373150900210X},
doi = {10.1016/j.jpdc.2009.10.006},
year = {2010},
date = {2010-02-01},
journal = {Journal of Parallel and Distributed Computing},
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pages = {144--159},
abstract = {A large scale High Level Architecture (HLA)-based simulation can be constructed using a network of simulation federations to form a ``federation community''. This effort is often for the sake of enhancing scalability, interoperability, composability and enabling information security. Synchronization mechanisms are essential to coordinate the execution of federates and event transmissions across the boundaries of interlinked federations. We have developed a generic synchronization mechanism for federation community networks with its correctness mathematically proved. The synchronization mechanism suits various types of federation community network and supports the reusability of legacy federates. It is platform-neutral and independent of federate modeling approaches. The synchronization mechanism has been evaluated in the context of the Grid-enabled federation community approach, which allows simulation users to benefit from both Grid computing technologies and the federation community approach. A series of experiments has been carried out to validate and benchmark the synchronization mechanism. The experimental results indicate that the proposed mechanism provides correct time management services to federation communities. The results also show that the mechanism exhibits encouraging performance in terms of synchronization efficiency and scalability.},
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A large scale High Level Architecture (HLA)-based simulation can be constructed using a network of simulation federations to form a ``federation community''. This effort is often for the sake of enhancing scalability, interoperability, composability and enabling information security. Synchronization mechanisms are essential to coordinate the execution of federates and event transmissions across the boundaries of interlinked federations. We have developed a generic synchronization mechanism for federation community networks with its correctness mathematically proved. The synchronization mechanism suits various types of federation community network and supports the reusability of legacy federates. It is platform-neutral and independent of federate modeling approaches. The synchronization mechanism has been evaluated in the context of the Grid-enabled federation community approach, which allows simulation users to benefit from both Grid computing technologies and the federation community approach. A series of experiments has been carried out to validate and benchmark the synchronization mechanism. The experimental results indicate that the proposed mechanism provides correct time management services to federation communities. The results also show that the mechanism exhibits encouraging performance in terms of synchronization efficiency and scalability.
Xiong, Muzhou; Lees, Michael; Cai, Wentong; Zhou, Suiping; Low, Malcolm Yoke Hean
Analysis of an efficient rule-based motion planning system for simulating human crowds Journal Article
In: The Visual Computer, 26 (5), pp. 367–383, 2010, ISSN: 0178-2789.
@article{DBLP:journals/vc/XiongLCZL10,
title = {Analysis of an efficient rule-based motion planning system for simulating human crowds},
author = {Muzhou Xiong and Michael Lees and Wentong Cai and Suiping Zhou and Malcolm Yoke Hean Low},
url = {http://link.springer.com/10.1007/s00371-010-0421-6},
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abstract = {This paper proposes a rule-based motion planning system for agent-based crowd simulation, consisting of sets of rules for both collision avoidance and collision response. In order to avoid an oncoming collision, a set of rules for velocity sampling and evaluation is proposed, which aims to choose a velocity with an expected time to collision larger than a predefined threshold. In order to improve the efficiency over existing methods, the sampling procedure terminates upon finding an appropriate velocity. Moreover, the proposed motion planning system does not guarantee a collision-free movement. In case of collision, another set of rules is also defined to direct the agent to make a corresponding response. The experiment results show that the proposed approach can be applied in different scenarios, while making the simulation execution efficient.},
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This paper proposes a rule-based motion planning system for agent-based crowd simulation, consisting of sets of rules for both collision avoidance and collision response. In order to avoid an oncoming collision, a set of rules for velocity sampling and evaluation is proposed, which aims to choose a velocity with an expected time to collision larger than a predefined threshold. In order to improve the efficiency over existing methods, the sampling procedure terminates upon finding an appropriate velocity. Moreover, the proposed motion planning system does not guarantee a collision-free movement. In case of collision, another set of rules is also defined to direct the agent to make a corresponding response. The experiment results show that the proposed approach can be applied in different scenarios, while making the simulation execution efficient.
Liang, Anson Yuanxi; Low, Malcolm Yoke-Hean; Lees, Michael Harold; Cai, Wentong; Zhou, Suiping
A framework of intelligent environment with smart-active objects (IESAO) for flexible and efficient crowd simulation Inproceedings
In: McGraw, Robert M; Imsand, Eric S; Chinni, Michael J (Ed.): Proceedings of the 2010 Spring Simulation Multiconference, SpringSim 2010, Orlando, Florida, USA, April 11-15, 2010, pp. 19, SCS/ACM, 2010, ISBN: 978-1-4503-0069-8.
@inproceedings{DBLP:conf/springsim/LiangLLCZ10,
title = {A framework of intelligent environment with smart-active objects (IESAO) for flexible and efficient crowd simulation},
author = {Anson Yuanxi Liang and Malcolm Yoke-Hean Low and Michael Harold Lees and Wentong Cai and Suiping Zhou},
editor = {Robert M McGraw and Eric S Imsand and Michael J Chinni},
doi = {10.1145/1878537.1878557},
isbn = {978-1-4503-0069-8},
year = {2010},
date = {2010-01-01},
booktitle = {Proceedings of the 2010 Spring Simulation Multiconference, SpringSim 2010, Orlando, Florida, USA, April 11-15, 2010},
pages = {19},
publisher = {SCS/ACM},
abstract = {Agent-based crowd simulation has been widely applied in the analysis of evacuation safety under disastrous and terrorist circumstances. In crowd simulation, the virtual environment plays an important role in influencing human behavior and defining the scenario. The concepts of informed environment and smart objects have been adopted to improve the realism of the simulation by embedding semantic information in the environment. However, there is no formal approach of using these concepts in crowd simulation. In this paper, we propose a flexible and efficient framework of Intelligent Environment with Smart and Active Objects (IESAO). We properly define different types of entities and interactions, and describe the approach of modeling environment-related behavior in the intelligent environment. This framework gives a new perspective of modeling human behavior in the design phase. An implementation and a case study are discussed to show the flexibility and efficiency of this framework.},
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Agent-based crowd simulation has been widely applied in the analysis of evacuation safety under disastrous and terrorist circumstances. In crowd simulation, the virtual environment plays an important role in influencing human behavior and defining the scenario. The concepts of informed environment and smart objects have been adopted to improve the realism of the simulation by embedding semantic information in the environment. However, there is no formal approach of using these concepts in crowd simulation. In this paper, we propose a flexible and efficient framework of Intelligent Environment with Smart and Active Objects (IESAO). We properly define different types of entities and interactions, and describe the approach of modeling environment-related behavior in the intelligent environment. This framework gives a new perspective of modeling human behavior in the design phase. An implementation and a case study are discussed to show the flexibility and efficiency of this framework.
2009
Wang, Yongwei; Lees, Michael; Cai, Wentong; Zhou, Suiping; Low, Malcol
Cluster based partitioning for agent-based crowd simulations Inproceedings
In: Dunkin, Ann; Ingalls, Ricki G; Yücesan, Enver; Rossetti, Manuel D; Hill, Ray; Johansson, Björn (Ed.): Proceedings of the 2009 Winter Simulation Conference (WSC), pp. 1047–1058, IEEE, 2009, ISBN: 978-1-4244-5770-0.
@inproceedings{DBLP:conf/wsc/WangLCZL09,
title = {Cluster based partitioning for agent-based crowd simulations},
author = {Yongwei Wang and Michael Lees and Wentong Cai and Suiping Zhou and Malcol Low},
editor = {Ann Dunkin and Ricki G Ingalls and Enver Yücesan and Manuel D Rossetti and Ray Hill and Björn Johansson},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5429649},
doi = {10.1109/WSC.2009.5429649},
isbn = {978-1-4244-5770-0},
year = {2009},
date = {2009-12-01},
booktitle = {Proceedings of the 2009 Winter Simulation Conference (WSC)},
pages = {1047--1058},
publisher = {IEEE},
abstract = {Simulating crowds is a challenging but important problem. There are various methodologies in the literature ranging from macroscopic numerical flow simulations to detailed, microscopic agent simulations. One key issue for all crowd simulations is scalability. Some methods address this issue through abstraction, describing global properties of homogeneous crowds. However, ideally a modeler should be able to simulate large heterogeneous crowds at fine levels of detail. We are attempting to achieve scalability through the application of distributed simulation techniques to agent-based crowd simulation. Distributed simulation, however, introduces its own challenges, in particular how to efficiently partition the load between a number of machines. In this paper we introduce a method of partitioning agents onto machines using an adapted k-means clustering algorithm. We present, validate and use an analysis tool to compare the proposed clustered partitioning approach with a series of existing methods.},
keywords = {},
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Simulating crowds is a challenging but important problem. There are various methodologies in the literature ranging from macroscopic numerical flow simulations to detailed, microscopic agent simulations. One key issue for all crowd simulations is scalability. Some methods address this issue through abstraction, describing global properties of homogeneous crowds. However, ideally a modeler should be able to simulate large heterogeneous crowds at fine levels of detail. We are attempting to achieve scalability through the application of distributed simulation techniques to agent-based crowd simulation. Distributed simulation, however, introduces its own challenges, in particular how to efficiently partition the load between a number of machines. In this paper we introduce a method of partitioning agents onto machines using an adapted k-means clustering algorithm. We present, validate and use an analysis tool to compare the proposed clustered partitioning approach with a series of existing methods.
Lees, Michael; Logan, Brian; Theodoropoulos, Georgios
Analysing probabilistically constrained optimism Journal Article
In: Concurrency and Computation: Practice and Experience, 21 (11), pp. 1467–1482, 2009.
@article{DBLP:journals/concurrency/LeesLT09,
title = {Analysing probabilistically constrained optimism},
author = {Michael Lees and Brian Logan and Georgios Theodoropoulos},
url = {http://doi.wiley.com/10.1002/cpe.1397},
doi = {10.1002/cpe.1397},
year = {2009},
date = {2009-08-01},
journal = {Concurrency and Computation: Practice and Experience},
volume = {21},
number = {11},
pages = {1467--1482},
abstract = {In previous work we presented the DTRD algorithm, an optimistic synchronization algorithm for parallel discrete event simulation of multi-agent systems, and showed that it outperforms Time Warp and time windows on a range of test cases. DTRD uses a decision-theoretic model of rollback to derive an optimal time to delay read event so as to maximize 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 event inter-arrival times increases, its performance degrades to that of Time Warp. The evaluation approach we present is generally applicable, and we sketch how a similar analysis may be performed for two other decision-theoretic optimistic synchronization algorithms.},
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In previous work we presented the DTRD algorithm, an optimistic synchronization algorithm for parallel discrete event simulation of multi-agent systems, and showed that it outperforms Time Warp and time windows on a range of test cases. DTRD uses a decision-theoretic model of rollback to derive an optimal time to delay read event so as to maximize 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 event inter-arrival times increases, its performance degrades to that of Time Warp. The evaluation approach we present is generally applicable, and we sketch how a similar analysis may be performed for two other decision-theoretic optimistic synchronization algorithms.
Stevens, David; Power, Henry; Lees, Michael; Morvan, Herve
The use of PDE centres in the local RBF Hermitian method for 3D convective-diffusion problems Journal Article
In: Journal of Computational Physics, 228 (12), pp. 4606–4624, 2009.
@article{DBLP:journals/jcphy/StevensPLM09,
title = {The use of PDE centres in the local RBF Hermitian method for 3D convective-diffusion problems},
author = {David Stevens and Henry Power and Michael Lees and Herve Morvan},
url = {http://linkinghub.elsevier.com/retrieve/pii/S0021999109001582},
doi = {10.1016/j.jcp.2009.03.025},
year = {2009},
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Xiong, Muzhou; Lees, Michael; Cai, Wentong; Zhou, Suiping; Low, Malcolm Yoke Hean
A Rule-Based Motion Planning for Crowd Simulation Inproceedings
In: Ugail, Hassan; Qahwaji, Rami; Earnshaw, Rae A; Willis, Philip J (Ed.): 2009 International Conference on CyberWorlds, pp. 88–95, IEEE, 2009, ISBN: 978-1-4244-4864-7.
@inproceedings{DBLP:conf/vw/XiongLCZL09,
title = {A Rule-Based Motion Planning for Crowd Simulation},
author = {Muzhou Xiong and Michael Lees and Wentong Cai and Suiping Zhou and Malcolm Yoke Hean Low},
editor = {Hassan Ugail and Rami Qahwaji and Rae A Earnshaw and Philip J Willis},
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isbn = {978-1-4244-4864-7},
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date = {2009-01-01},
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abstract = {This paper proposes a rule-based motion planning system for agent-based crowd simulation, consisting of sets of rules for both collision avoidance and collision response. In order to avoid an on-coming collision, a set of rules for velocity sampling and evaluation is proposed, which aims to choose a velocity with an expected time to collision larger than a defined threshold. In order to improve the efficiency over existing methods, the sampling procedure terminates upon finding an appropriate velocity. Moreover, the proposed motion planning system does not guarantee a collision-free movement. In case of collision, another set of rules is also defined to direct the agent to make a corresponding response. The experiment results show that the proposed method can be applied into different scenarios, while making the simulation execution efficient.},
keywords = {},
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This paper proposes a rule-based motion planning system for agent-based crowd simulation, consisting of sets of rules for both collision avoidance and collision response. In order to avoid an on-coming collision, a set of rules for velocity sampling and evaluation is proposed, which aims to choose a velocity with an expected time to collision larger than a defined threshold. In order to improve the efficiency over existing methods, the sampling procedure terminates upon finding an appropriate velocity. Moreover, the proposed motion planning system does not guarantee a collision-free movement. In case of collision, another set of rules is also defined to direct the agent to make a corresponding response. The experiment results show that the proposed method can be applied into different scenarios, while making the simulation execution efficient.
Orsini, P; Power, H; Morvan, H; Lees, M
An implicit upwinding volume element method based on meshless radial basis function techniques for modelling transport phenomena Journal Article
In: International Journal for Numerical Methods in Engineering, 81 (1), pp. n/a–n/a, 2009.
@article{NME:NME2682,
title = {An implicit upwinding volume element method based on meshless radial basis function techniques for modelling transport phenomena},
author = {P Orsini and H Power and H Morvan and M Lees},
url = {http://dx.doi.org/10.1002/nme.2682 http://doi.wiley.com/10.1002/nme.2682},
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year = {2009},
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Luo, Linbo; Zhou, Suiping; Cai, Wentong; Low, Malcolm Yoke Hean; Lees, Michael
Toward a Generic Framework for Modeling Human Behaviors in Crowd Simulation Inproceedings
In: 2009 IEEE/WIC/ACM International Joint Conference on Web Intelligence and Intelligent Agent Technology, pp. 275–278, IEEE, 2009, ISBN: 978-0-7695-3801-3.
@inproceedings{DBLP:conf/iat/LuoZCLL09,
title = {Toward a Generic Framework for Modeling Human Behaviors in Crowd Simulation},
author = {Linbo Luo and Suiping Zhou and Wentong Cai and Malcolm Yoke Hean Low and Michael Lees},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5284829},
doi = {10.1109/WI-IAT.2009.163},
isbn = {978-0-7695-3801-3},
year = {2009},
date = {2009-01-01},
booktitle = {2009 IEEE/WIC/ACM International Joint Conference on Web Intelligence and Intelligent Agent Technology},
pages = {275--278},
publisher = {IEEE},
abstract = {This paper presents our ongoing work on modeling agents with human-like decision making and behavior execution capabilities in crowd simulation. We aim to provide a generic framework that reflects the major cognitive and physical processes as observed from human behaviors in real-life situations. The design of the framework is based on some basic assumptions and related cognitive theories on human behaviors in various real-life situations. In this paper, the cognitive architecture of our framework is presented, which emphasizes the role of experiences in human's decision making. The paper also briefly describes the design of agent's decision making process and presents a case study to show some results in a crowd simulation scenario.},
keywords = {},
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This paper presents our ongoing work on modeling agents with human-like decision making and behavior execution capabilities in crowd simulation. We aim to provide a generic framework that reflects the major cognitive and physical processes as observed from human behaviors in real-life situations. The design of the framework is based on some basic assumptions and related cognitive theories on human behaviors in various real-life situations. In this paper, the cognitive architecture of our framework is presented, which emphasizes the role of experiences in human's decision making. The paper also briefly describes the design of agent's decision making process and presents a case study to show some results in a crowd simulation scenario.