Federation Object Model Research Articles

On the role of future HLA-based simulation in designing safety into space vehicles

This paper discusses High Level Architecture (HLA) based simulation in the context of designing safety into space vehicles. Distributed simulation plays an important role to fuse the two worlds of safety on the one hand and cost effectiveness on the other hand. HLA represents a simulation system architecture framework standard and focuses on interoperability and reusability of simulation components. The article analyzes the impact of the usage of the future HLA version called HLA 4 on space vehicle design. New possibilities with an increased level of loose component coupling in combination with the establishment of a-priori interoperability by using the Space Reference Federation Object Model (SpaceFOM) standard are presented.

SpaceFOM - A robust standard for enabling a-priori interoperability of HLA-based space systems simulations

ABSTRACT The development of modern space systems requires the collaboration among several national and international space organisations. Along with this complexity and diversity come progressively increasing challenges with managing the associated requirements, properties, emergent behaviours, and integration risks. Collaborative and distributed simulation is one technology being applied to address these challenges. A notable example of this is the well-established standard for distributed simulation, the IEEE 1516-2010 – High Level Architecture (HLA). To enable and ensure a-priori interoperability for complex space systems simulations and foster international collaboration, the Simulation Interoperability Standards Organization (SISO) formed a Product Development Group (PDG) to develop the Space Reference Federation Object Model (SpaceFOM). This article presents the SpaceFOM standard describing the principal design elements that compose it along with a set of design patterns introduced to deal with common issues in distributed simulation and to pursue extensibility, interoperability, and robustness.

Infrastructure System Simulation Interoperability Using the High-Level Architecture

Infrastructure planners need new methods to exchange technical data in the pursuit of long-term and cross-sector objectives including sustainability. This paper demonstrates a method for infrastructure system simulation interoperability by applying the high-level architecture (HLA) to the infrastructure system of systems (ISoS) modeling framework. The ISoS considers time-aggregated simulations with iterative data exchange periods to resolve cyclic dependencies. Applying the HLA defines object models, operational agreements, federate implementations, and physical infrastructure required for a federated simulation. An example demonstrates the method on a scenario with 18 infrastructure elements across water, electricity, petroleum, and social sectors as individual federates. The cost of interoperability arises from network latency, runtime infrastructure (RTI) overhead, and additional development effort. Results across several RTIs show that a distributed simulation requires 10-100 times longer executions than noninteroperable configurations. Analysis of source code shows that the HLA contributes about 1500 (56%) more software lines of code to implement federation object models and agreements. The value of interoperability arises from new capabilities provided by the HLA: physical distribution and independent control of constituent models. Conclusions describe a role for the HLA in model-based concept exploration during collaborative and interorganizational design activities with live human participation similar to its use for wargames.

Integrated coupling of road traffic and network simulation for realistic emulation of connected vehicle applications

To meet the requirements of connected vehicle (CV) system simulation evaluations, different simulators (i.e., traffic flow simulation, network communication simulation and CV application simulation) must be combined and interaction must be enabled among them during the run-time of the simulation. This paper proposes a CV simulation prototype system based on integration of three components in one coupling. Considering the characteristics of the distributed interactive simulation of multi-emulators, a high-level architecture simulation and modeling concept is used to construct the simulation framework, and the three types of simulation elements are defined as the primary federates. The integration simulation system is constructed by defining the federation object model and developing the support environment of the run-time infrastructure during simulation. In the simulation implementation procedure, a commercial-off-the-shelf time-stepped VISSIM simulator and an open-source event-driven NS2 simulator are selected as the basic simulation tools to develop the system. In addition, selected related technologies are investigated, including the NS2 simulation model transformation, time synchronization management strategy, track consistency strategy, and integration of application members. Finally, two case studies of intersection speed guidance and collision warning are used to verify the validity of the simulation prototype system.

Ontology Fusion in High-Level-Architecture-Based Collaborative Engineering Environments

In high-level-architecture (HLA)-based distributed heterogeneous collaborative engineering environments (CEEs), the construction of federation object model files is time consuming. This paper presents an ontology fusion approach aiming at establishing a common understanding in such collaborative environments. The proposed approach has three steps: ontology mapping, ontology alignment, and ontology merging. Ontology mapping employs a top-down approach to explore all bridge relations between two terms from different ontologies based on bridge axioms and deduction rules. Ontology alignment adopts a bottom-up approach to discover implicit bridge relations between two terms from different domain ontologies based on equivalent inference. Ontology merging generates a new collaboration ontology from discovered equivalent bridge relations. It adopts an axiom-based ontology fusion strategy and takes heavy-weighted ontologies into consideration. It can find all the explicit and derived interontology relations. In a typical CEE, the proposed approach has a great potential to improve the efficiency of preparation for HLA-based collaborative engineering processes, reduce the work load for adaptive adjustment of existing platforms, and enhance the reusability and flexibility of CEEs. A case study has been conducted to validate the feasibility of the proposed approach.

하이브리드 데이터 통신 방식을 적용한 IEEE 1516.1-2000 표준의 구현

최근 국방 소프트웨어 산업은 다양한 무기체계 사업을 통해 모델링 및 시뮬레이션 기술을 적용한 시뮬레이션 시스템 개발을 늘리고 있으며, 특히 이기종 시뮬레이터 간 이식성 및 상호 연동성 확보를 위해서 분산 시뮬레이션 표준 프레임워크인 HLA(High Level Architecture)의 적용을 규정하고 있다. HLA는 분산 환경에서 시뮬레이터간 데이터 교환 및 순서화를 제공하기 위한 서비스를 정의하며, HLA 규칙, Federate 인터페이스 표준 그리고 객체 모델 템플릿의 주요 컴포넌트로 구성된다. RTI(Run-Time Infrastructure)는 Federate 인터페이스 표준을 구현한 소프트웨어로써 Federation 환경에 참여 중인 Federate들이 정보를 교환할 수 있도록 기능을 제공한다. RTI 기술은 워 게임, 가상 시뮬레이션, 훈련 및 무기체계 소프트웨어 연동과 같은 다양한 분야에서 사용되고 있다. 하지만 국내에서 개발된 사례가 없어 모두 외산 제품에 의존하고 있는 실정이다. 본 논문은 국내에서 개발된 IEEE1516.1-2000 표준의 RTI 구현을 소개한다. 특히, Federate 간 데이터 교환 성능을 높이기 위해서 서버-클라이언트 방식과 단대단 방식을 혼합한 하이브리드 데이터 통신 방식의 적용 방법을 기술하고, 상용 RTI와 데이터 처리율 및 네트워크 지연 시간의 비교를 통해 성능이 개선되었음을 보인다. Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This technology is a software which is to provide the core technology which was suggested by the United state's military M&S standard framework. Simulator, virtual simulation, and inter-connection between military weapons system S/W which executes on network which is M&S's core base technology, and it is a technology which also can be used for various inter-connection between S/W such as game and on-line phone. These days although RTI is used in military war game or tactical training unit field, there is none in Korea. Also, it is used in mobile-game, distribution game, net management, robot field, and other civilian field, but the number of examples are so small and informalized. Through this developing project, we developed the core technique and RTI software and provided performance of COTS level to improve communication algorithms.

Ontology-based interoperation model of collaborative product development

The reuse of existing systems is an important objective of High Level Architecture (HLA) based collaborative product development systems. However, in order to reuse an existing system, its interoperation interface has to be modified so as to comply with the objective and interaction representations defined in a corresponding Federation Object Model (FOM). Such modifications imply added time and effort, which diminishes the efficiency of system reuse in collaborative product development. This paper presents a heavy-weighted ontology-based construction method for interoperation models to support the reuse of subsystems in various collaborative contexts. In this method ontologies are used to specify the semantics of object classes and interaction classes in subsystems in a formal and computer readable fashion. In doing so, a Formal Concept Analysis (FCA) like construction method is introduced to establish the original interoperation ontology from scratch. An automatic transforming method from Simulation Object Model (SOM) into interoperation ontology is also described to make existing HLA based systems easy to adopt this approach. Then a consistency verification method is introduced to guarantee the consistency of the interoperation ontologies. A case study is used to demonstrate the feasibility of the proposed method. As a human-friendly modeling method, compared with existing interoperation modeling methods the proposed method is more flexible, efficient and reliable.

An Introduction of BOM Modeling Framework

Component based modeling has been a research hotpot in the area of Modeling and Simulation for a long time. In order to increase the reusability and interoperability of models, this paper put forward a component based modeling framework called BOM Modeling Framework (BMF) based on BOM specification. The structure, principles, formalisms and behaviors of BMF were presented in detail first. The description and framework of Atomic BOM model and coupled BOM model in BMF were studied in succession. At last, the developing process of BMF models was introduced. The prototype developed showed that BMF could not only promote the reusability and interoperability of models but also improve the efficiency and easy the process of M&S. To simplify model development and further promote the reusability and interoperability of models, SISO (Simulation Interoperability Standards Organization) put forward the BOM (Base Object Model) specification (1)(2) which was proposed as a SISO standard in 2006. The BOM concept is based on the assumption that piece-parts of models, simulations, and federations can be extracted and reused as modeling building-blocks or components. The interplay within a simulation or federation can also be captured and characterized in the form of reusable patterns. These patterns of interplay are sequences of events between simulation elements. The representation of the pattern of interplay is captured in the BOM. BOM has an obvious brand of High Level Architecture (HLA) (3)(4). The origin of BOM is to overcome the shortcoming that HLA federates are highly coupled with the used Federation Object Model (FOM) of federation which makes federates hard to reuse and interoperate directly. If federation's FOM changes, the federates can't be reused anymore and need lots of modification along with FOM. BOM provides an important component modeling mechanism for M&S. And it is considered as a key technology for the next-generation simulation, for that it can enhance standardization, encapsulation, composability, interoperability and reusability

A HLA federation simulation modelling approach for multimodal transportation system of ports

This paper proposes a modelling approach for a simulation model of multimodal transportation system of ports in High-Level Architecture (HLA) distributed federation simulation environment. In this model, the simulation federation consists of Operation Federates (OFs) and a Coordination Management Federate (CMF). The OF simulates the local logistics operation subsystems such as port, road and railway operation with the discrete event system simulation model. The CMF coordinates the total operation according to the system status of OFs. The modelling process has five steps including analysis of the system structure, establishment of the simulation federation, design of OFs and the CMF, establishment of the Federation Object Model (FOM) and implemention of the simulation federation. An actual case is illustrated to show the modelling steps and advantages in decreasing difficulty and complexity in modelling.

High Level Architecture Object Model Development And Supporting Tools

The purpose of this article is to familiarize the reader with the activities currently underway within the Defense Modeling and Simulation Office (DMSO) to provide supporting pro cesses and tools for HLA federation and object model development. The article begins by introducing the fundamental concepts of an HLA federation and HLA object model, and identifies the processes that have been defined to guide their development. The HLA Tool Architecture is then discussed, which defines the overarching framework within which the HLA object modeling tools are described. Next, a use case example is presented to illustrate how automated tools facilitate the HLA object model development process. Finally, the mecha nisms in place to provide user support for HLA object modeling tools and processes are identi fied, as well as DMSO initiatives to foster a marketplace for commercial tool development.