CERTI, an Open Source RTI, why and how

CERTI is an HLA RTI developed since 1996 by ONERA, the French Aerospace Lab. The initial purpose of CERTI was to develop a home made RTI in order to: learn HLA usage and HLA RTI internals (e.g. time management), have total control over source code in order to use this particular RTI with specific modifications in several research projects (security mechanism, multi-resolution, high performance distributed simulation...). CERTI became open source in 2002: https://savannah.nongnu.org/projects/certi. Since then, Open Source CERTI project has had variable activity periods, mostly driven by research project needs and funds. CERTI development has started again since the end of 2006, with an increased interest from the open source user community. After a brief status survey of CERTI, this presentation will focus on the Open Source objectives of CERTI and explain why this is not a product but a project driven OSS initiative, pushed by a Public establishment like ONERA. We will further explain how open sourceness CERTI stimulates its development and the community itself and why every stakeholder benefits from this

Iterchanging Discrete Event Simulationprocess Interaction Modelsusing The Web Ontology Language - Owl

Discrete event simulation development requires significant investments in time and resources. Descriptions of discrete event simulation models are associated with world views, including the process interaction orientation. Historically, these models have been encoded using high-level programming languages or special purpose, typically vendor-specific, simulation languages. These approaches complicate simulation model reuse and interchange. The current document-centric World Wide Web is evolving into a Semantic Web that communicates information using ontologies. The Web Ontology Language OWL, was used to encode a Process Interaction Modeling Ontology for Discrete Event Simulations (PIMODES). The PIMODES ontology was developed using ontology engineering processes. Software was developed to demonstrate the feasibility of interchanging models from commercial simulation packages using PIMODES as an intermediate representation. The purpose of PIMODES is to provide a vendor-neutral open representation to support model interchange. Model interchange enables reuse and provides an opportunity to improve simulation quality, reduce development costs, and reduce development times

DISTRIBUTED SIMULATION IN INDUSTRY – A SURVEY PART 3 – THE HLA STANDARD IN INDUSTRY

Distributed simulation, more specifically the HLA standard, is hardly applied in industry. We have conducted an extensive survey with COTS (commercial off-the-shelf) simulation package vendors and simulation experts, both from defence and industry, that focuses, amongst others, on the question what the reasons are behind this phenomenon. In this paper we analyze the reactions that we obtained, categorizing them into arguments related to distributed simulation in general, arguments related to HLA and arguments pertaining to the embedding of HLA concepts in COTS packages. These answers will lead us, we believe, to insights that can serve as guidelines to make distributed simulation more attractive for the industrial simulation community.

A Framework To Model Complex Systems Via Distributed Simulation: A Case Study Of The Virtual Test Bed Simulation System Using the High Level Architecture

As the size, complexity, and functionality of systems we need to model and simulate con-tinue to increase, benefits such as interoperability and reusability enabled by distributed discrete-event simulation are becoming extremely important in many disciplines, not only military but also many engineering disciplines such as distributed manufacturing, supply chain management, and enterprise engineering, etc. In this dissertation we propose a distributed simulation framework for the development of modeling and the simulation of complex systems. The framework is based on the interoperability of a simulation system enabled by distributed simulation and the gateways which enable Com-mercial Off-the-Shelf (COTS) simulation packages to interconnect to the distributed simulation engine. In the case study of modeling Virtual Test Bed (VTB), the framework has been designed as a distributed simulation to facilitate the integrated execution of different simulations, (shuttle process model, Monte Carlo model, Delay and Scrub Model) each of which is addressing differ-ent mission components as well as other non-simulation applications (Weather Expert System and Virtual Range). Although these models were developed independently and at various times, the original purposes have been seamlessly integrated, and interact with each other through Run-time Infrastructure (RTI) to simulate shuttle launch related processes. This study found that with the framework the defining properties of complex systems - interaction and emergence are realized and that the software life cycle models (including the spiral model and prototyping) can be used as metaphors to manage the complexity of modeling and simulation of the system. The system of systems (a complex system is intrinsically a system of systems ) continuously evolves to accomplish its goals, during the evolution subsystems co-ordinate with one another and adapt with environmental factors such as policies, requirements, and objectives. In the case study we first demonstrate how the legacy models developed in COTS simulation languages/packages and non-simulation tools can be integrated to address a compli-cated system of systems. We then describe the techniques that can be used to display the state of remote federates in a local federate in the High Level Architecture (HLA) based distributed simulation using COTS simulation packages

A study on Discrete Event Simulation (DES) in a High-Level Architecture (HLA) networked simulation

This thesis investigates implementing Discrete Event Simulation (DES) concepts using Simkit packages into a High- Level Architecture (HLA)-networked simulation, thus addressing sustainability of the HLA methodology into the future. Through the DES concept of predicting and anticipating the time of when events will occur, redundant and excessive exchange of common data, like position and sensory status, can be removed. This DES implementation considerably reduces the network load and removes data processing incompatibility between simulations. A design involving several concepts of DES and HLA simulation led to the creation of a Simkit based application library. Interfacing this application library with two DES models demonstrated and proved the feasibility of DES concepts in HLA-networked simulations. A generic combat scenario modeled using this methodology, successfully showed the intended advantages of the thesis. The ease of linking non-DES and non-HLA simulations to an HLA environment was enhanced using a common set of interfaces built based on the resulting application library. Through a simple comparison with traditional time-stepped real-time simulation of the same scenario configuration, it was shown that data exchange between simulations was reduced by several orders of magnitude. This freed a substantial amount of network resources to perform other tasks, hence, improving network performance.http://archive.org/details/astudyondiscrete109454958(Simulation Systems) author (civilian)Approved for public release; distribution is unlimited

Giving life to the map can save more lives. Wildfire scenario with interoperable simulations

Abstract. In the Mediterranean region, drier and hotter summers are leading to more likely and severe wildfires. The authors propose an innovative approach for situational awareness by giving life to maps and exploiting interoperable GIS, hazard models, simulations, and interconnection analysis processes aimed to enhance preparedness and strengthen the resilience of responding organizations. The information related to a virtual city and its countryside has been implemented in the terrain of simulation systems. The TIGER wildfire model software has been adapted to a scenario where districts, refugee camps and critical infrastructures can be impacted by a fire and has been linked to a smoke dispersion model, and associated impacts to the electricity network and roads. The transfer of computed fire propagation and combustion data to the AI-powered SWORD simulation enable more accurate computing of damage and loss. In SWORD, civil protection, military assets and humanitarian actions can be performed for training and operation preparation. The simulation data about fire and assets' deployments can feed a web app map or a command and control system, thus providing situational awareness for optimal decision-making, and analysis about people in danger, network interconnections and potential service disruption. Disaster managers and commanders can interact with simulated assets performing their chosen courses of action and analyse the outcomes.In conclusion, tests in a wildfire case study demonstrated a high level of interoperability among those systems and the possibility to provide updated situational awareness leading to better emergency preparedness and critical infrastructure resilience building, finally contributing to save more lives.</p

Application of Web Services to a Simulation Framework

The Joint Semi-Automated Forces (JSAF) simulator is an excellent tool for military training and a great testbed for new SAF behaviors. However, it has the drawback that behaviors must be ported into its own Finite State Machine (FSM) language. Web Services is a growing technology that seamlessly connects service providers to service consumers. This work attempts to merge these two technologies by modeling SAF behaviors as web services. The JSAF simulator is then modeled as a web service consumer. This approach allows new Semi-Automated Forces (SAF) behaviors to be developed independently of the simulator, which provides the developer with greater flexibility when choosing a programming language, development environment, and development platform. In addition to new SAF behaviors, this approach also supports any external component that can be modeled as a web service. Furthermore, these services are often run over a network, which distributes the computational load across several computers. Finally, hosting copies of a single service on several machines, a concept similar to file-sharing mirrors, offers an environment for load-balancing. This means if several entities are running the same behavior, a single server does not perform the computation for every entity. Instead, each entity is assigned to a specific server, increasing the quality of service seen by the system. A Web Services framework linking JSAF with several services is designed and implemented. Suppression of Enemy Air Defense (SEAD) behaviors written in MATLAB and a behavior recognition system are integrated with JSAF. These behaviors and the recognition tool were developed by other researchers, independent of this work. Results show that offloading computation to other machines is beneficial, especially when the simulation system is under heavy load. Preliminary results also indicate that load-balancing performs much better than using a single server

Transportation system modeling using the High Level Architecture

This dissertation investigates the High Level Architecture (HLA) as a possible distributed simulation framework for transportation systems. The HLA is an object-oriented approach to distributed simulations developed by the Department of Defense (DoD) to handle the issues of reuse and interoperability of simulations. The research objectives are as follows: (1) determine the feasibility of making existing traffic management simulation environments HLA compliant; (2) evaluate the usability of existing HLA support software in the transportation arena; (3) determine the usability of methods developed by the military to test for HLA compliance on traffic simulation models; and (4) examine the possibility of using the HLA to create Internet-based virtual environments for transportation research. These objectives were achieved in part via the development of a distributed simulation environment using the HLA. Two independent traffic simulation models (federates) comprised the environment (federation). A CORSIM federate models a freeway feeder road with an on-ramp while an Arena federate models a tollbooth exchange

Performance Analysis of Live-Virtual-Constructive and Distributed Virtual Simulations: Defining Requirements in Terms of Temporal Consistency

This research extends the knowledge of live-virtual-constructive (LVC) and distributed virtual simulations (DVS) through a detailed analysis and characterization of their underlying computing architecture. LVCs are characterized as a set of asynchronous simulation applications each serving as both producers and consumers of shared state data. In terms of data aging characteristics, LVCs are found to be first-order linear systems. System performance is quantified via two opposing factors; the consistency of the distributed state space, and the response time or interaction quality of the autonomous simulation applications. A framework is developed that defines temporal data consistency requirements such that the objectives of the simulation are satisfied. Additionally, to develop simulations that reliably execute in real-time and accurately model hierarchical systems, two real-time design patterns are developed: a tailored version of the model-view-controller architecture pattern along with a companion Component pattern. Together they provide a basis for hierarchical simulation models, graphical displays, and network I/O in a real-time environment. For both LVCs and DVSs the relationship between consistency and interactivity is established by mapping threads created by a simulation application to factors that control both interactivity and shared state consistency throughout a distributed environment