[show abstract][hide abstract] 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.
Journal of Parallel and Distributed Computing 04/2013; 70(2):144-159. · 1.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: Vince Gaffney, Phil Murgatroyd, Bart Craenen, and Georgios Theodoropoulos
‘Only individuals’: moving the Byzantine army to Manzikert pp. 25-43
Traditionally, history has frequently emphasized the role of the ‘Great Man or Woman’, who may achieve greatness, or notoriety, through the consequences of their decisions. More problematic is the historical treatment of the mass of the population. Agent-based modelling is a computer simulation technique that can not only help identify key interactions that contribute to large scale patterns but also add detail to our understanding of the effects of all contributors to a system, not just those at the top. The Medieval Warfare on the Grid project has been using agent-based models to examine the march of the Byzantine army across Anatolia to Manzikert in AD 1071. This article describes the movement model used to simulate the army and the historical sources on which it was based. It also explains why novel route pla
01/2013: pages 25-44; , ISBN: ISBN 978‐1‐905670‐49‐9
[show abstract][hide abstract] ABSTRACT: Digital Humanities offer a new exciting do-main for agent-based distributed simulation. In historical studies interpretation rarely rises above the level of un-proven assertion and is rarely tested against a range of evidence. Agent-based simulation can provide an opportu-nity to break these cycles of academic claim and counter-claim. The MWGrid framework utilises distributed agent-based simulation to study medieval military logistics. As a use-case, it has focused on the logistical analysis of the Byzantine army's march to the battle of Manzikert (AD 1071), a key event in medieval history. It integrates an agent design template, a transparent, layered mechanism to translate model-level agents' actions to timestamped events and the PDES-MAS distributed simulation kernel. The paper presents an overview of the MWGrid system and a quantitative evaluation of its perfomance.
16th IEEE International Symposium on Distributed Simulation and Real Time Applications (DSRT 2012); 10/2012
[show abstract][hide abstract] ABSTRACT: As the scale of Distributed Virtual Environments (DVEs) grows in terms of participants and virtual entities, using interest management schemes to reduce bandwidth consumption becomes increasingly common for DVE development. The interest matching process is essential for most of the interest management schemes which determines what data should be sent to the participants as well as what data should be filtered. However, if the computational overhead of interest matching is too high, it would be unsuitable for real-time DVEs for which runtime performance is important. This paper presents a new approach of interest matching which divides the workload of matching process among a cluster of computers. Experimental evidence shows that our approach is an effective solution for the real-time applications.
Distributed Simulation and Real Time Applications (DS-RT), 2011 IEEE/ACM 15th International Symposium on; 10/2011
[show abstract][hide abstract] ABSTRACT: Reputation and trust-based models have been used extensively in different application domains. These include large online communities such as eBay, Amazon, YouTube and ad-hoc and wireless sensor networks. Recently, the use of the models has gained popularity due to their effectiveness in providing trusted systems or networks. Thesemodels focus on online and historical data to determine the reputation of domain members. In this paper, we propose a novel approach for obtaining trust values by focusing not only on online and historical data but also possible future scenarios to anticipate events in the next time intervals. The data-driven framework is able to dynamically obtain and inject data to predict the future trust value of every identity in the system. The advantage of this proactive approach compared to other approaches is that informed decisions about the domain can be made before a compromise occurs.
[show abstract][hide abstract] ABSTRACT: Interest management provides scalable data distribution for large-scale distributed virtual environments by filtering irrelevant messages on the network. The interest matching process is essential for most of the interest management schemes which determines what data should be sent to the participants as well as what data should be filtered. Most of the existing interest matching approaches focus on reducing the computational overhead of the matching process. However, they have a fundamental disadvantage - they perform interest matching at discrete time intervals. As a result, they would fail to report events between two consecutive time-steps of simulation. If participants ignore these missing events, they would most likely perform incorrect simulations. This paper presents a new algorithm for continuous interest matching which aims to capture missing events between discrete time-steps. Although our approach requires additional matching steps, we employ a efficient algorithm to significantly reduce this overhead.
Principles of Advanced and Distributed Simulation (PADS), 2010 IEEE Workshop on; 06/2010
[show abstract][hide abstract] ABSTRACT: Range-Query is an important associative form of data access in distributed simulations and Distributed Virtual Environments. This paper discusses the problem of Range-Queries in the context of distributed simulation of multi-agent systems. An algorithm is presented for performing instantaneous Queries within an optimistic synchronisation framework and in the presence of dynamic migration of the simulation state. A quantitative evaluation of the effectiveness of the algorithm under different conditions is also presented.
DS-RT '10 Proceedings of the 2010 IEEE/ACM 14th International Symposium on Distributed Simulation and Real Time Applications, Fairfax, Virginia, USA, 17-20 October 2010; 01/2010
[show abstract][hide abstract] ABSTRACT: The use of learning objects (LOs) to support learning processes is considered a key factor in the deployment of e-learning frameworks. Although their discrete and selfcontained nature offers many advantages LOs have presented courseware designers with two fundamental issues. The first issue concerns the adequate identification of the learning objects and the second relates to their integration into a suitable learning programme. This paper is concerned with the presentation of a framework that addresses and reconciles these requirements by capitalising on the metadata of the learning objects and on the profiles of the learners. The learning process is mediated by a core component, a learning management system (LMS) that, through a registry, accesses the metadata of the learning objects published by providers and acts as a repository of metadata. In addition, it enables learners to construct learning paths (LP) from a set of relevant LOs in accordance with their profile. The LMS can also generate automatically a learning path on behalf of a learner and determine the schedule of the learning process. The implementation of the framework takes advantage of the flexibility of Web Services.
ICALT 2010, 10th IEEE International Conference on Advanced Learning Technologies, Sousse, Tunisia, 5-7 July 2010; 01/2010