Developing interest management techniques in distributed interactive simulation using Java

Bandwidth consumption in distributed real time simulation, or networked real time simulation, is a major problem as the number of participants and the sophistication of joint simulation exercises grow in size. The paper briefly reviews distributed real time simulation and bandwidth reduction techniques and introduces the Generic Runtime Infrastructure for Distributed Simulation (GRIDS) as a research architecture for studying such problems. GRIDS uses Java abstract classes to promote distributed services called thin agents, a novel approach to implementing distributed simulation services, such as user defined bandwidth reduction mechanisms, and to distributing the executable code across the simulation. Thin agents offer the advantages of traditional agents without the overhead imposed by mobility or continuous state, which are unnecessary in this context. We present our implementation and some predicted results from message reduction studies using thin agent

Distributed Individual-Based Environmental Simulation

This paper describes the development and construction of a distributed model allowing the simulation of a large population. Particular attention will be paid to allowing the modelling of an individual's behaviour, communication and interaction with a shared environment. Individual based modelling is not a new concept, nor is the idea of distributed simulations, the system detailed here offers a means of combining these two paradigms into one large-scale modelling environment. A key concept in this system is that each individual being modelled is implemented as a separate process. This atomisation of the model allows the simulation a greater flexibility, individuals can be rapidly developed and the simulation can be spread over a wide number of machines of varying architectures. In an attempt to produce a flexible, extensible, individual based model of a large number of individual subjects the client-server paradigm has been employed. Combining the individual-based modelling techniques with a client-server network architecture has been found to be quite straightforward with the added bonus of having communication between individuals included for free. The idea of considering the problem as one of interaction between an individual and the environment means that the problems normally associated with distributed simulations, those of continuity of world-views for different clients and of communication between clients, are easily solved. Although this system has been developed originally to allow simulations of the Mountain Gorilla (Gorilla Gorilla Beringe) population, the modelling methods employed have meant that almost any entity can be simulated with very little change to the basic simulation processes

Facilitating the analysis of a UK national blood service supply chain using distributed simulation

In an attempt to investigate blood unit ordering policies, researchers have created a discrete-event model of the UK National Blood Service (NBS) supply chain in the Southampton area of the UK. The model has been created using Simul8, a commercial-off-the-shelf discrete-event simulation package (CSP). However, as more hospitals were added to the model, it was discovered that the length of time needed to perform a single simulation severely increased. It has been claimed that distributed simulation, a technique that uses the resources of many computers to execute a simulation model, can reduce simulation runtime. Further, an emerging standardized approach exists that supports distributed simulation with CSPs. These CSP Interoperability (CSPI) standards are compatible with the IEEE 1516 standard The High Level Architecture, the defacto interoperability standard for distributed simulation. To investigate if distributed simulation can reduce the execution time of NBS supply chain simulation, this paper presents experiences of creating a distributed version of the CSP Simul8 according to the CSPI/HLA standards. It shows that the distributed version of the simulation does indeed run faster when the model reaches a certain size. Further, we argue that understanding the relationship of model features is key to performance. This is illustrated by experimentation with two different protocols implementations (using Time Advance Request (TAR) and Next Event Request (NER)). Our contribution is therefore the demonstration that distributed simulation is a useful technique in the timely execution of supply chains of this type and that careful analysis of model features can further increase performance

Modular HLA RTI services: The GRIDS approach

The Generic Runtime Infrastructure for Distributed Simulation (GRIDS) has been developed to investigate modularity issues in distributed simulation. It could be argued that although the HLA RTI is a widespread solution to distributed simulation, it cannot include all possible services. This paper investigates an approach to extending the distributed simulation services available in the HLA RTI. One example of this is bridging support for HLA/DIS legacy integration. This paper therefore presents GRIDS, how GRIDS can be used to provide modular service support for the HLA RTI, and a case study on legacy integration to demonstrate our approach

Distributed simulation and the grid: Position statements

The Grid provides a new and unrivaled technology for large scale distributed simulation as it enables collaboration and the use of distributed computing resources. This panel paper presents the views of four researchers in the area of Distributed Simulation and the Grid. Together we try to identify the main research issues involved in applying Grid technology to distributed simulation and the key future challenges that need to be solved to achieve this goal. Such challenges include not only technical challenges, but also political ones such as management methodology for the Grid and the development of standards. The benefits of the Grid to end-user simulation modelers also are discussed

Investigating distributed simulation with COTS simulation packages: Experiences with Simul8 and the HLA

Commercial-off-the-shelf simulation packages (CSPs) are used widely in industry. Several research groups are currently working towards the creation of distributed simulation with these CSPs. The motivations to do this are various and are largely unproven as there are very few good examples of this kind of distributed simulation in practice. Our goal is therefore to create a distributed simulation environment using CSPs that will allow end users to make their own decisions as to whether this technology will be useful. This paper presents continuing research in creating such an environment using the CSP Simul8 and the High Level Architecture, the IEEE 1516 standard for distributed simulation. The scope of this paper is limited to the CSPI-PDG Type I Interoperability Reference Model

Investigating distributed simulation at the Ford motor company

Engine production is a complex process that requires the manufacturing and assembly of a wide variety of components to create a varied product mix. Simulation plays a key role in the planning process of a new production line to determine if it can meet expected demand. However, these simulations can be very time consuming and can often take up to a day to execute a single run. This paper investigates how distributed simulation based on the IEEE 1516 High Level Architecture and the emerging standard COTS Simulation Package Interoperability Product Development Group (CSPI-PDG) Type I Interoperability Reference Model could be used to reduce the time taken for a single simulation run. CSP interoperability and the problem of integrating CSPs with HLA software (the runtime infrastructure) are presented. New prototype benchmarking software, the COTS Simulation Package Emulator (CSPE), which is being developed to investigate distributed simulation problems, is discussed. The paper then develops a case study of how this was used to investigate the feasibility of using distributed simulation at Ford. The paper discusses results obtained from this case study and suggests that distributed simulation could indeed be beneficial to Ford