Chang Ho Sung

DEVSim++Toolset for Defense Modeling and Simulation and Interoperation

Discrete Event Systems Specification (DEVS) formalism supports the specification of discrete event models in a hierarchical and modular manner. Efforts have been made to develop the simulation environments for the modeling and simulation (M&S) of systems using DEVS formalism, particularly in defense M&S domains. This paper introduces the DEVSim++ toolset and its applications. The Object-Analysis Index (OAI) matrix is a tabular form of objects and analysis indices for requirements analysis. DEVSim++ is a realization of DEVS formalism in C++ for M&S. VeriTool is a DEVS model verification tool. DEVSimHLA is a library to support High-level Architecture (HLA) in DEVSim++. Other tools, including KComLib, FOM2CPPClass, and KHLAAdaptor, are used to develop a smart adaptor that allows for the interoperation of simulators of any kind. PlugSim is a distributed simulation framework using plug-in methods. These tools are utilized in every stage of the M&S development process, as well as in every application of the M&S missions to the military domain. Accordingly, the applications implemented by the toolset are used in the training, analytic, and acquisition missions of the Republic of Korea military branches. We expect the DEVS applications to become more prolific as M&S demands grow, and our toolset is already proven as complete and efficient in the domain of defense M&S.

Framework for Simulation of Hybrid Systems: Interoperation of Discrete Event and Continuous Simulators Using HLA/RTI

A hybrid system is a combination of discrete event and continuous systems that act together to perform a function not possible with any one of the individual system types alone. A simulation model for the system consists of two sub-models, a continuous system model, and a discrete event model, and interfaces between them. Naturally, the modeling/simulation tool/environment of each sub- model may be different and specific to the model types and the associated modeling formalisms. This paper proposes a framework for simulating hybrid systems by means of interoperation between existing simulators for a continuous model and a discrete event model using a High Level Architecture (HLA). Each simulator is executed using different simulation algorithm, and pre-simulation methodology is applied for synchronization of the different simulators. The main advantage of the proposed approach is the reuse of simulation models, which are developed in their own simulation environments of heterogeneous types. The proposed framework was applied to water level simulation.

Collaborative Modeling Process for Development of Domain-Specific Discrete Event Simulation Systems

The discrete event systems specification (DEVS) formalism supports the object-oriented (OO) specification of discrete event models in a hierarchical, modular manner. If a system that is to be modeled is domain-specific, the development of models with the use of the DEVS formalism would require domain knowledge about the system as well as to understand DEVS semantics. This paper proposes a collaborative modeling process to compensate for the lack of professional engineers. To compensate, this modeling process utilizes three types of engineers: domain engineer, modeling and simulation (M&S) engineer, and platform engineer. The process consists of four steps: conceptual modeling, model partition, model implementation, and model integration/simulation. The system requirements are used to specify domain models in the conceptual modeling step, and the models are partitioned into two types: discrete event-level model (DEM) and behavioral-level model (BM). The DEM is specified as the DEVS formalism, and the BM is defined as algorithms and equations. Each model is implemented separately, and the implemented models are integrated and simulated flexibly by using a dynamic linking library. The modeling process is then applied to develop a war game simulator. The advantage of this modeling process is that the collaborative work is related to the whole series of steps. This collaboration maximally utilizes the capabilities of the professional engineers by seamlessly separating yet correlating their works.

Collaborative Work in Domain-Specific Discrete Event Simulation Software Development: Fleet Anti-air Defense Simulation Software

Modeing and simulation (M&S) is an important method to evaluate numerous designs and operational concepts for a real-world system. If a system to be modeled is domain-specific, developing the simulation software of the system will require domain knowledge about the system as well as understanding the M&S methodology. This paper describes M&S stakeholders and proposes a collaborative work process in the development of domain-specific simulation software. M&S stakeholders are persons with their own professional knowledge: subject matter experts (SME), domain engineers, M&S engineers, platform engineers, and simulation data analysts. The M&S process consists of eight activities from defining modeling objectives to analyzing simulation data, and diverse M&S stakeholders work together in each activity. The M&S process is applied to develop a real-world M&S software development experience in a military domain. Through the proposed collaborative work process, the capabilities of the M&S stakeholders can be utilized maximally by seamlessly separating yet correlating their works.

Hierarchical Federation Composition for Information Hiding in HLA-Based Distributed Simulation

This paper presents a hierarchical federation system interconnected among federations and proposes a hierarchical federation composition algorithm that composes federations into different compositions of hierarchical federations and then efficiently assigns composite federations to a distributed environment while enabling information hiding. We implement the hierarchical federation system and evaluate it using real networks. The experimental results show that our composition algorithm performs better than a random composition algorithm in optimizing the composition of federations while achieving information hiding.

A binary partition-based matching algorithm for data distribution management

Data Distribution Management (DDM) is one of the High Level Architecture (HLA) services that reduce message traffic over the network. The major purpose of the DDM is to filter the exchange of data between federates during a federation. However, this traffic reduction usually suffers from higher computational overhead when calculating the intersection between update regions and subscription regions in a matching process. In order to reduce the computational overhead for the matching process, this paper proposes a binary partition-based matching algorithm for DDM in the HLA-based distributed simulation. The new matching algorithm is fundamentally based on a divide-and-conquer approach. The proposed algorithm recursively performs binary partitioning which divides the regions into two partitions that entirely cover those regions. This approach promises low computational overhead, since it does not require unnecessary comparisons within regions in different partitions. The experimental results show that the proposed algorithm performs better than the existing DDM matching algorithms and improves the scalability of the DDM.

A binary partition-based matching algorithm for Data Distribution Management in a High-level Architecture-based distributed simulation

Data Distribution Management (DDM) is one of the High-level Architecture (HLA) services that reduce message traffic over the network. The major purpose of DDM is to filter and route the exchange of data between federates during a federation. However, this traffic reduction usually results in a significant computational overhead, which is caused by calculating the intersection between update regions and subscription regions in a matching process. To reduce the computational overhead for the matching process, this paper proposes a binary partition-based matching algorithm for DDM in a HLA-based distributed simulation. The new matching algorithm is fundamentally based on a divide-and-conquer approach. The proposed algorithm recursively performs binary partitioning that divides the regions into two partitions that entirely cover those regions. This approach promises low computational overhead, since it does not require unnecessary comparisons within regions in different partitions. The experimental results show that the proposed algorithm performs the existing DDM-matching algorithms better and improves the scalability of the DDM.