• Journal of Internet Computing and Services
• /
• v.16 no.6
• /
• pp.69-78
• /
• 2015

Recently, research on the multi-agent system is developed actively in the various fields, especially on the control of complex system and optimization. In this study, we develop a multi-agent system for NPC simulation in game environment. The purpose of the development is to support quick and precise decision by inferencing the situation of the dynamic discrete domain, and to support an optimization process of the agent system. Our approach employed Petri-net as a basic agent model to simplify structure of the system, and used fuzzy inference engine to support decision making in various situation. Our experimentation describes situation of the virtual battlefield between the NPCs, which are divided two groups, such as fuzzy rule based agent and automata based agent. We calculate the percentage of winning and survival rate from the several simulations, and the result describes that the fuzzy rule based agent showed better performance than the automata based agent.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.11
• /
• pp.939-943
• /
• 2001

PLC(programmable Logic Controller)s essential components of modern automation systems encompassing almost every industry. Ladder Diagrams (LD) have been widely used in the design of such PLC since the LD is suitable for the modeling of the sequential control system. However, the synthesis of LD itself mainly depends on the experience of the industrial engineer, which may results in unstructured or inflexible design. Hence, in this paper, we propose a ladder diagram conversion algorithm which systematically produces LDs for PLCs based on discrete event models to enhance the structured and flexible design mechanism.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.5
• /
• pp.401-406
• /
• 2002

As product lifecycles become shorter, factories are pushed to develop small batches of many different products. The highly flexible control systems has become a necessity. The majority of existing automated industrial systems are controlled by programmable logic controllers(PLCs). In most cases, the control programs for PLCs are developed based on ladder diagrams(LDs). However, it is difficult to debug and maintain those LDs because the synthesis of LD itself mainly depends on the experience of the industrial engineer via trial-and-error methods. Hence, in this paper, we propose a discrete event model conversion algorithm for systematic analysis of LDs. The proposed discrete event model conversion algorithm is illustrated by an example of a conveyor system.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2002.11a
• /
• pp.143-148
• /
• 2002

본 연구는 미국방성에서 시뮬레이션 시스템간의 표준화 분산 미들웨어 기술인 HLA와 이산 사건 시스템 형식론(DEVS: Discrete Event System Specification)을 이용한 가상전장 분산 시뮬레이션을 목적으로 한다. 최근 군체계 시뮬레이션은 지상전, 공중전, 해상전, 미사일전, 정보전 등 현대 전투개념을 모두 반영할 수 있도록 그 활용 범위가 넓어지고 있다. 따라서 기존에 개발되어 사용되고 있는 각종 군체계 시뮬레이션들을 통합하여 운영하려고 하고 있으나 각각의 시뮬레이션들은 그 목적에 따라 각기 다른 환경에서 개발되어졌기 때문에 통합환경을 제공하기가 쉽지 않다. 따라서 본 논문에서는 기존에 연구된 DEVS 기반 가상전장 환경을 확장하여 전장의 다양한 요소들을 계층 구조적으로 통합하고 HLA이 적용하여 분산 시뮬레이션 실험을 하였다. 이렇게 함으로써 분산 환경 하에서 통합 가상 전장 환경을 제공할 수 있으며, 대단위 부대의 실험시 시뮬레이션의 성능향상을 기대할 수 있다.

• Journal of the Korea Society for Simulation
• /
• v.29 no.1
• /
• pp.71-79
• /
• 2020

As the urbanization trend in modern society continues, the concentration of the population induces the urban problems in the residential area. One of the well-known issues among various urban problems is the garbage problem, which causes deterioration of the residential environment of citizens and directly affects the satisfaction of municipal administration. Such garbage problem cannot be accurately predicted by analyzing the amount of waste emitted from residential areas, but it is necessary to analyze the lifestyle and characteristics of residents living in residential areas. In this study, we propose an agent-based residential modeling and simulation environment using discrete event system formalism to analyze the garbage problem and satisfaction level according to the distribution of residents in the residential area. To model the behavior of the residents, we utilized the Atomic Model to capture the temporal behavior. Also, we used the Coupled Model to model the multi-family and the building to enhance the reusability of the simulation model. Also, this study carried out simulation modeling and simulation for a multi-family residential area. The simulation results of the multi-family housing area show that considering the characteristics of the residents gives better results compared to the simulation results without considering the characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.12
• /
• pp.1700-1709
• /
• 2019

Recently, many researches have been under way to develop systems (services) to support the safety navigation of ships, and in these studies, common difficulties have been encountered in assessing the usefulness and effectiveness of the developed system. To solve these problems, we propose the DEVS-based ship navigation modeling and simulation technique. Following the preceding study, we analyze the COLREG rules and reflected to officer and helmsman agent models for decision making. Also we propose estimation and interpolation techniques to adopt the motion characteristics of the actual vessel to simulation. In addition, we implement the navigation simulation system to reflect the designed proposed methods, and we present five-scenarios to verify the developed simulation system. And we conduct simulations according to each scenario and the results were reconstructed. The simulation results confirm that the components modelled in each scenario enable to operate according to the navigation relationships.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.10
• /
• pp.94-117
• /
• 1998

This paper investigates the performance characteristics of the data link layer of the 1996 version of IEC/ISA fieldbus which is developed as internatioal standard of fieldbus. A discrete-event simulation model of the data link layer of IEC/ISA fieldbus is developed. Using the simulation model, this paper identifies the network parameters that influence the performance of prioritys scheme and real-time data transmission, and analyzes the delay performance of IEC/ISA fieldbus with respect to the change of network parameters. The simulation model also integrates continuous-time simulation model of a control system as application process. Using the integrated simulation model, this study investigates the effect of network-induced delay on the performance of control system. Since the simulation model developed in this study can predict the network performance, it will be effectively utilized in the design phase of control and automation systems that adopt the IEC/ISA fieldbus.

• The KIPS Transactions:PartA
• /
• v.10A no.2
• /
• pp.111-122
• /
• 2003

Military wargame simulation models must support the HLA in order to facilitate interoperability with other simulations, and using parallel simulation engines offer efficiency in reducing system overhead generated by propelling interoperability. However, legacy military simulation model engines process events using sequential event-driven method. This is due to problems generated by parallel processing such as synchronous reference to global data domains. Additionally. using legacy simulation platforms result in insufficient utilization of multiple CPUs even if a multiple CPU system is under use. Therefore, in this paper, we propose conversing the simulation engine to an object model-based parallel simulation engine to ensure military wargame model's improved system processing capability, synchronous reference to global data domains, external simulation time processing, and the sequence of parallel-processed events during a crash recovery. The converted parallel simulation engine is designed and implemented to enable parallel execution on a multiple CPU system (SMP).

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.10
• /
• pp.78-88
• /
• 1990

To evaluate the performance of a multiprocessor system, a discrete event model of memory interference in the system employing multiple-bus interconnection networks is proposed. An analytic model of the system is presented and then simulator models are implemented for cross-verifying the analytic results and simulation results. The simulator model takes as input the number of processors, the number of memory modules, the number of buses and the local memory miss ratio. The model produces as output the memory bandwidth, the processor, memory module and bus utilization and the bus contention ratio. Using the model in the design of the system, it is possible to evaluate the system performance by analyzing the interaction of the input parameters.

• Journal of the Korea Society for Simulation
• /
• v.28 no.4
• /
• pp.1-10
• /
• 2019

The Sea Water Reverse Osmosis (SWRO) plant should take into account the availability of the plant from the design stage for long-term and continuous fresh water production. As it occurs, it is necessary to establish a corrective maintenance plan and preventive maintenance plan to maintain availability. In the field of complex engineering structures such as seawater desalination plants, it is difficult to estimate the reliability or availability of the system in a mathematical way. This study develops RAM analysis framework and model, and proposes discrete event simulation model as a application sowtware specialized for seawater desalination plant. Considering the characteristics of the plant maintenance, in case of corrective maintenance, we propose a preventive maintenance policy that not only repairs or replaces a single-broken part, but also simultaneously maintains all accessible parts according to the level of overhaul. A case study was conducted to estimate the availability of the system based on the field data of the seawater desalination plant in Korea and Saudi Arabia. The result was close to the expected availability of the plant.