Distributed Simulation Architecture Research Articles

Digital Battle: A Three-Layer Distributed Simulation Architecture for Heterogeneous Robot System Collaboration

In this paper, we propose a three-layer distributed simulation network architecture, which consists of a distributed virtual simulation network, a perception and control subnetwork, and a cooperative communication service network. The simulation architecture runs on a distributed platform, which can provide unique virtual scenarios and multiple simulation services for the verification of basic perception, control, and planning algorithms of a single-robot system and can verify the distributed collaboration algorithms of heterogeneous multirobot systems. Further, we design simulation experimental scenarios for classic heterogeneous robotic systems such as unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs). Through the analysis of experimental measurement data, we draw several important conclusions: firstly, the replication time characteristics and update frequency characteristics of entity synchronization in our system indicate that the replication time of entity synchronization in our system is relatively short, and the update frequency can meet the needs of multirobot collaboration and ensure the real-time use and accuracy of the system; secondly, we analyze the bandwidth usage of data frames in the whole session and observe that the server side occupies almost half of the data throughput during the whole session, which indicates that the allocation and utilization of data transmission in our system is reasonable; and finally, we construct a bandwidth estimation surface model to estimate the bandwidth requirements of the current model when scaling the server-side scale and synchronization-state scale, which provides an important reference for better planning and optimizing of the resource allocation and performance of the system. Based on this distributed simulation framework, future research will improve the key technical details, including further refining the coupling object dynamic model update method to support the simulation theory of the coupling relationship between system objects, studying the impact of spatiotemporal consistency of distributed systems on multirobot control and decision making, and in-depth research on the impact of collaborative frameworks combined with multirobot systems for specific tasks.

A unified cloud-enabled discrete event parallel and distributed simulation architecture

Cloud infrastructure provides rapid resource provision for on-demand computational requirements. Cloud simulation environments today are largely employed to model and simulate complex systems for remote accessibility and variable capacity requirements. In this regard, scalability issues in Modeling and Simulation (M&S) computational requirements can be tackled through the elasticity of on-demand Cloud deployment. However, implementing a high performance cloud M&S framework following these elastic principles is not a trivial task as parallelizing and distributing existing architectures is challenging. Indeed, both the parallel and distributed M&S developments have evolved following separate ways. Parallel solutions has always been focused on ad-hoc solutions, while distributed approaches, on the other hand, have led to the definition of standard distributed frameworks like the High Level Architecture (HLA) or influenced the use of distributed technologies like the Message Passing Interface (MPI). Only a few developments have been able to evolve with the current resilience of computing hardware resources deployment, largely focused on the implementation of Simulation as a Service (SaaS), albeit independently of the parallel ad-hoc methods branch. In this paper, we present a unified parallel and distributed M&S architecture with enough flexibility to deploy parallel and distributed simulations in the Cloud with a low effort, without modifying the underlying model source code, and reaching important speedups against the sequential simulation, especially in the parallel implementation. Our framework is based on the Discrete Event System Specification (DEVS) formalism. The performance of the parallel and distributed framework is tested using the xDEVS M&S tool, Application Programming Interface (API) and the DEVStone benchmark with up to eight computing nodes, obtaining maximum speedups of 15.95× and 1.84×, respectively.

Research on Key Technologies of Event-driven Distributed Cooperative Simulation

In this paper, an event driven strategy is used to design a distributed simulation system, and a distributed simulation architecture of three-tiers is proposed. Based on the service-oriented design of event-driven distributed simulation system, the hierarchical design of WCF-based simulation hierarchy is completed, and the data transfer and loose coupling between the components of the architecture are realized. Considering the system-level modeling idea based on the design structure matrix, an improved event scheduling method is proposed and the incident management technology is studied. Based on the above research, a simulation system was designed and developed. Taking the multidisciplinary modeling and simulation of the all-electric telecommunication satellite as a case, the simulation application integration and simulation results were analyzed to verify the versatility and correctness of the simulation system.

PARALLELISM AND COMPLEXITY OF A SMALL-WORLD NETWORK MODEL

The small-world phenomena exhibits highly localized clustering and short-cut paths between vertices in a graph that reflect observed properties in social networks, epidemiological models and other real-world networks. The small-world models rely on the application of constraint-based randomness or the derivation of constraints on randomness to simulate the desired network complexities and their associated network connection properties. In this paper, rather than exploring the random properties of small-world networks, we employ deterministic strategies in the design of a computationally efficient distributed neuronal-axon network simulator that results in a small world network. These strategies are derived by addressing the parallel complexities of the proposed neuronal-axon network simulator, and also from physical constraints imposed by resource limitations of the distributed simulation architecture. The outcome of this study is the realization of a neuronal-axon network simulator that exhibits small-world characteristics of clustering with a logarithmic degree of separation between nodes without the need for long-range communication edges. The importance of this result is the deterministic application of reasoned optimization rules from which the small-world network emerges.

A unifying framework for specifying DEVS parallel and distributed simulation architectures

DEVS (Discrete Event System Specification) is an approach in the area of modeling and simulation that provides a means of specifying dynamic systems. A variety of DEVS tools have been implemented without a standard developmental guideline across the board, consequently revealing a lack of central frameworks for integrating heterogeneous DEVS simulators. When implementing a DEVS Simulator there are salient concepts that are intuitively defined, such as how events should be processed, what simulation architecture to use, what existing procedures (set of rules/algorithm) can be used, what should be the organizational architecture and so on. The aim of this paper is to propose a theoretical guide in building a DEVS distributed simulation as well as a formalization of underlying concepts to allow symbolic reasoning and automated code synthesis. From a review of existing implementation approaches, we propose a taxonomy of the identified concepts, including some formal definitions as they constitute the essential building blocks of performing Parallel Discrete-Event Simulation by utilizing DEVS. The contribution of this taxonomy and its impact as a unifying framework is that it provides a more systematic understanding of the process of constructing a DEVS simulator. Also, it offers an abstract way for integrating different and heterogeneous DEVS implementation strategies and thus can serve as a contribution to the on-going DEVS standardization efforts.

Quantifying radar measurement errors in a Live–Virtual–Constructive environment to determine system viability: a case study

We present a case study that attempts to replicate the realism of a test range using a Live, Virtual and Constructive (LVC) simulation. Because resources are limited on a real test range, the Air Force Simulation and Analysis Facility at Wright-Patterson Air Force Base, Ohio, was tasked to build a simulation that emulated, to a high degree of fidelity, test range assets – the goal was to understand the impact of jamming on an enemy’s integrated air defense system. Before testing began, the simulated effects generated by the LVC simulation have to be viable, robust and realistic in order to provide credible data during later phases of experimentation. We present our approach to evaluating the correctness of the LVC simulation that considers sources of error associated with real-world radar measurements, errors caused by model abstraction and errors introduced due to real-time distributed simulation architectures, including shared state-space inconsistencies, coordinate conversion issues and a common time reference.

Parallel Network Simulation With OMNeT++

This paper reports a new parallel and distributed simulation architecture for OMNeT++, an open-source discrete event simulation environment. The primary application area of OMNeT++ is the simulation of communication networks. Support for a conservative PDES protocol (the Null Message Algorithm) and the relatively novel Ideal Simulation Protocol has been implemented.Placeholder modules, a novel way of distributing the model over several logical processes (LPs) is presented. The OMNeT++ PDES implementation has a modular and extensible architecture, allowing new synchronization protocols and new communication mechanisms to be added easily, which makes it an attractive platform for PDES research, too. We intend touse this framework to harness the computational capacity of highperformance cluster computersfor modeling very large scale telecommunication networks to investigate protocol performance and rare event failure scenarios.

An architecture for Grid-enabled distributed simulation

The application of distributed simulation techniques to ever more complex problems calls for more computational power. The emergence of the Grid provides an opportunity to address this challenge and thus make advances in the modelling and analysis of large-scale systems by harnessing the power of many computers. These requirements are met by the design and development of frameworks that support the integration of appropriate Distributed Simulation Kernels (DSK) and Grid middleware. This paper presents a framework and a prototype implementation for specifying and executing distributed simulations over the Grid. The framework incorporates a well established DSK with the Globus middleware.

A decoupled federate architecture for high level architecture-based distributed simulation

A number of research issues arise in executing large scale High Level Architecture (HLA) based distributed simulations. Among these issues distributed simulation cloning, fault tolerance and Grid enabled architecture are particularly important and challenging. This paper presents a Decoupled Federate Architecture as the underlying infrastructure to facilitate a solution to each of the above issues. Distributed simulation cloning has been designed to improve the performance of “what-if” analysis, by enabling the examination of alternative scenarios concurrently within the same execution session. Furthermore, simulation federates running at different locations are liable to failure. Such risk increases with the scale of a distributed simulation. The architecture has also been exploited to form the basis of a generic framework to support runtime robustness. The development of complex simulation applications often requires geographically distributed huge computing resources and data sets. Using the architecture, Web and Grid technologies have been successfully combined with existing simulation technologies thus to enhance interoperability and execution flexibility for such simulations. Benchmark experiments have been performed to study the extra overhead incurred by the Decoupled Federate Architecture against a normal federate. Encouraging experimental results indicate that a well designed architecture can achieve performance close to the normal one in terms of latency and time synchronization. Additional experiments have been presented for evaluating the three solutions supported by the architecture.

Integrating crowd-behavior modeling into military simulation using game technology

Crowds of noncombatants play a large and increasingly recognized role in modern military operations and often create substantial difficulties for the combatant forces involved. However, realistic models of crowds are essentially absent from current military simulations. To address this problem, the authors are developing a crowd simulation capable of generating crowds of noncombatant civilians that exhibit a variety of realistic individual and group behaviors at differing levels of fidelity. The crowd simulation is interoperable with existing military simulations using a standard, distributed simulation architecture. Commercial game technology is used in the crowd simulation to model both urban terrain and the physical behaviors of the human characters that make up the crowd. The objective of this article is to present the design and development process of a simulation that integrates commercially available game technology with current military simulations to generate realistic and believable crowd behavior.

A Distributed Mechanical System Simulation Platform Based on a “Gluing Algorithm”

Three key concepts are presented in this paper, which comprise the foundation of a distributed simulation platform for design and virtual prototyping of general mechanical systems that have their subsystems distributed amongst dispersed development units in multilayered supply chains. First, a general and efficient model description for simulation is defined using XML. Each model is described with an XML file and stored in model database. A complete model can then be assembled based on these model descriptions. Simulation of a model is started simply by sending the model description to a simulation server and running it through a web-based graphics user interface. Second, a new gluing algorithm, denoted as the T-T method, is developed, which enables distributed simulations (both the component models and simulation of the components) to be coupled while maintaining the independence of the separate component simulations. Third, a logical distributed simulation architecture is laid out that can be implemented with one of the existing technologies for distributed computing. Interfaces between different network components have been standardized to enable extensibility of the architecture. These concepts have been incorporated into a prototype web-based distributed simulation system that demonstrates the potential of the new techniques for solving real engineering design problems.

生産システムのためのリアルワールドとシミュレーションワールドの結合 : 第二報 ソフト結線システムと設備シミュレータ(S60-1 生産システムの新展開(1),S60 生産システムの新展開)

Our objective is to establish a simulation system that can be used easily throughout the manufacturing system life cycle. Therefore, we have been developing the manufacturing simulation system by using distributed simulation architecture, HLA. However, it is too difficult to apply the simulation system to the implementation stage of real factory line, because the simulation language is not executable on the real equipment. In this paper, we describe a method and a system for introducing the real equipment or its emulator into the manufacturing simulation. As a result, the user can simulate the motion etc. of the machine with the dedicated tools of the equipment.

2919 HLA による動的分散スケジュールを用いた分散型生産システム

In an advanced factory, higher and higher flexibility is required to meet a grate variety of customers' requirements. In this environment, a dynamic management architecture is required for a distributed production system. In this paper, a newly distributed simulation architecture called HLA (High Level Architecture) is utilized to achieve a distributed scheduling simulation for dynamic job assignment and flexible working group configuration in a distributed production system. It is verified that the distributed scheduling simulation based on HLA is effective to achieve higher flexibility for a distributed production system, by several case studies.

The Joint Tactical Combat Training System System Model

ABSTRACT The Joint Tactical Combat Training System (JTCTS) is a joint Navy/Air Force program to provide enhanced tactical combat training from single‐platform warfighting through integration of multi‐platform coordinated combat training (surface, subsurface, and air). Key requirements of JTCTS include the use of the Global Positioning System to generate platform position information, simulated platforms and weapons, and a real‐time radio datalink to transmit training data within 400 run of a JTCTS core‐capable site, using a distributed simulation architecture derived from distributed interactive simulations.Many design tradeoffs need to be made to implement this system. To enable the meaningful test and tradeoff of various design options, a software model of the JTCTS system was constructed. This discrete‐event simulation was implemented entirely in software running on commercial workstations. The model allows the designers to test various software and hardware design implementations and measure their influence on the “goodness” of the exercise data. Based on platform attitude and relative position, datalink connectivity can be assessed and various message‐passing algorithms tested. The effects of message latency and communications dropouts on dead‐reckoning accuracy can be directly measured. Effects of aircraft antenna shading, atmospheric effects on radio frequency propagation, and others can be turned on or off depending on the needs of the particular test, and to support validation of the model.The engineering model was created during the project concept definition; it is being used today in a number of design studies. One, a datalink transmitter power tradeoff, is giving insight into the relationship between the accuracy of after‐action reports and the heat dissipation of the datalink components. These simulated exercises are providing both the end‐user and the design team with insight into subsystem and operational interactions usually not seen until system integration testing.