Distributed Interactive Simulation

Abstract: SIMNET was the first successful implementation of large-scale, real-time, man-in-the-loop simulator networking for team training and mission rehearsal in military operations. The paper provides some historical background on how SIMNET was developed within the US Department of Defense, and outlines the key philosophical and architectural principles on which it was based. The SIMNET battlefield simulation was sponsored by ARPA (then called DARPA), in partnership with the US Army, and was developed and implemented between 1983 and 1990. The emphasis of SIMNET from the outset was on enhancing tactical team performance by providing commanders and troops an opportunity to practice their skills in a dynamic, free-play environment, in which battle outcomes depend on team coordination and individual initiative, rather than on scripted scenarios controlled by an instructor. This program demonstrated the feasibility of linking together hundreds or thousands of simulators (representing tanks, infantry fighting vehicles, helicopters, fired-wing aircraft, etc.) to create a consistent, virtual world in which all participants experience a coherent, logical sequence of events. In this world, the causal connections among these tactical events, from the individual crew station to the battalion command post, are clear and easily inspectable. The SIMNET architecture and protocols have evolved into the Distributed Interactive Simulation (DIS) Standard Protocols (IEEE 1278-1993 and its successors), and have provided the foundation for a new generation of battlefield simulations for training, mission rehearsal, tactics development, evaluation of hypothetical new battlefield systems, and concept testing and evaluation. The authors are two of the principal architects of SIMNET: Thorpe was the original DARPA SIMNET program manager and Miller formed and led the group at Bolt Beranek and Newman, Inc. (BBN) that designed and implemented the SIMNET protocols and software. >

Abstract: A Distributed Interactive Simulation provides the illusion of a single, coherent virtual world to a group of users located at different machines connected by a network. Users expect to see a consistent world view, to interact closely with one another and with other simulation entities in the virtual world, and to be shielded from the application's distributed nature. Networked virtual environments are used for multiplayer video games, military and industrial training, and collaborative engineering. Network bandwidth, network latency, and host processing power limit the achievable size and detail of future simulations. This thesis describes network protocols and algorithms to support remote modeling, allowing a host to model and render remote entities in large-scale distributed simulations. These techniques require fewer network resources and support more entity types than previous approaches. The Position History-Based Dead Reckoning (PHBDR) protocol provides accurate remote position modeling and minimizes dependencies on network performance and entity representation. PHBDR is a foundation for three protocols: (1) Axis Point Protocol: Models entity orientation by tracking the position of points in the entity's local coordinate system. (2) Multiple-Detail Channels: Protocol architecture for modeling entity structural change at different levels of detail depending on locally available computational and network resources. (3) Projection Aggregation Entities: Protocol for bundling information from entities dynamically grouped by their type and location. This thesis shows that a simple, efficient protocol can provide smooth, accurate remote position modeling and that it can be applied recursively to support entity orientation, structure, and aggregation at multiple levels of detail; these protocols offer performance and costs that are competitive with more complex and application-specific approaches, while providing simpler analyses of behavior by exploiting this recursive structure. In support of this claim, this thesis shows that: (1) PHBDR is a simple, efficient protocol that provides smooth and accurate remote modeling for a broad range of entities and explicitly recognizes network latency. (2) PHBDR is still smooth and accurate when used to model entity orientation, entity structure at multiple levels of detail, and entity aggregations. (3) The recursive protocol structuring provides better network performance and reduced software complexity when compared with the application-specific approaches deployed in previous systems.

Abstract: Simulating physically realistic complex fluid behaviors in a distributed interactive simulation (DIS) presents a challenging problem for computer graphics researchers. The authors consider how solving the 2D Navier-Stokes equations via a computational fluid dynamics method lets us map surfaces into 3D and achieves realistic real-time fluid surface behaviours.

Abstract: A manager system provides a set of integrated tools designed to assist in all stages of the military engagement training cycle: exercise creation, monitoring, and review. All information created or gathered at each stage is automatically made available to the next training stage. It can be distributed on the World-Wide Web, or can be viewed using a Web browser. The manager system uses the protocols established by the Distributed Interactive Simulation Standard (DIS) to both send and receive information from other DIS applications in order to perform each training stage. This allows the manager system to simultaneously monitor multiple dissimilar DIS training simulators during a joint exercise.