• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.145-149
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• 1997

This paper describes a methodology for the development of models of discrete event system. The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can coupled discrete event system models within a framework. The structure employs the discrete event specification formalism for the discrete event system models. The proposed formal structure has been applied to develop a discrete event specification model for the complex spectral density analysis of strip for urin analyzer system. For this, spectral density data of strip is partitioned into a set of Phases based on events identified through urine spectrophotometry. For each phase, a continuous system of the continuous model for the urine spectral density analysis has been simulated by programmed C++. To validate this model, first develop the discrets event specification model, then simulate the model in the DEVSIM++ environment. It has the similar simulation results for the data obtained from the continuous system simulation. The comparison shows that the discrete event specification model represents dynamics of the urine spectral density at each phase.

• Ocean Systems Engineering
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• v.7 no.3
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• pp.247-273
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• 2017

Many different engagement situations require naval ships to achieve some level of effectiveness. The performance of the naval ships is very important for such effectiveness. There have been many studies that analyze the effectiveness and the performance. The former are largely related to engagement level simulations, while the latter are largely related to engineering level simulations. However, there have been few studies that consider both the engagement level and the engineering level at the same time. Therefore, this study presents three case studies using engagement simulation of the engineering level to check the performance of the related parameters. First, detection performance simulations are carried out by changing the specifications of the passive sonars of a submarine in different scenarios. Maneuvering performance simulations are carried out by changing the specification of the hydroplanes of a submarine in different scenarios. Lastly, in order to check whether or not our forces would succeed in attacking enemy forces, we perform an engagement simulation with various naval ship models that consist of several engineering level models, such as command systems, weapon systems, detection systems, and maneuver systems. As a result, the performance according to the specifications of the naval ships and weapons is evaluated.

• Journal of the Korea Society for Simulation
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• v.17 no.2
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• pp.49-61
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• 2008

Most battleship warfare M&S systems run relatively slow and the simulation results are often unfair since the system should interact with human operators(controller and/or gamer). To deal with these problems, we have proposed the agent-based battleship warfare M&S system which interact with multiple agent systems instead of human operators. Agent-based M&S system may be able to efficiently support the analysis of effectiveness and/or the operational tactics development of given warfare by providing autonomous reasoning capabilities without the intervention of human controller. To do this, the paper propose the design concept and methodology using the advanced modeling and simulation framework as well as autonomous agent design principle. Several simulation tests performed on the battleship warfare case study on Korea Yellow sea will illustrate our techniques.

• Journal of the Korea Society for Simulation
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• v.17 no.1
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• pp.33-42
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• 2008

In general, simulation is to predict or evaluate some systems that are hard to be executed in real world, and so usually the target systems to be modeled are large and complex. Trying to observe the dynamics of the systems results in similar level of animation complexity, the model and animation has the same complexity as the system. Trying to display all the graphic objects representing the dynamics of the models being simulated, however, causes the distraction of focus, which results in solving the above listed problems difficult. The redundant graphic objects also increase the computer computation overhead. To solve the problem, a research about a hierarchical animation environment has been proposed a few years ago. In the research, the users can have better focus on the dynamics of system components by selectively choosing the hierarchical level and components within a level of the hierarchically structured model. However, the research has not a modeling methodology for modelers to describe systematically animation part corresponding to dynamics of simulation in a model. This research has defined the modeling methodology of DESHA and defined DESHA-C++, improving the previous research output, as an execution environment of DESHA models. In addition, to use hierarchical animation environment in various problems, this research proposed and developed the distributed simulation modeling environment that connects DESHA environment and HLA.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.793-796
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• 2007

RFID (Radio Frequency IDentification) 리더의 동작 영역은 리더의 감도와 전력이 도달할 수 있는 거리에 의해 제한된다. RFID Shower 는 근접한 리더로부터 전송되는 신호를 증폭하여 리더의 동작영역을 확장한다. 그러나, RFID Shower 의 동작 영역 안에 여러 리더들이 있을 경우 리더들간의 신호충돌이 발생한다. 이를 해결하기 위해 중재 알고리즘이 제안되었다. 본 논문에서는 RFID 리더들을 위한 중재 알고리즘을 DEVS 형식론에 기반하여 모델링하고 시뮬레이션 하여 성능을 측정, 비교하였다.

• Journal of the Korea Society for Simulation
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• v.26 no.2
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• pp.9-17
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• 2017

The problem of social phenomenon is getting more complicated than past decades, and the simulation engineers need more computation power to solve the problem. Therefore, the needs of the computational resources of the modeling and simulation environment are increasing. In the perspective of the simulation, it is necessary to allocate computational resources flexibly so that the simulation can be performed per the available budget range. As an alternative to the simulation environment to accommodate these requirements, cloud service has emerged as an environment in which computing resources can be used flexibly. This paper proposes a web-based simulation framework which consists of a front-end that reconstructs the simulation model using the web, and a back-end that executes the discrete event simulation. This paper also carried out a case study which shows web-based simulation framework has better overall runtime than standalone simulation framework.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.49-56
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• 2007

This paper deals with grid job allocation and grid resource scheduling to provide a stable and quicker job processing service to grid users. In this paper, we proposed a fuzzy logic-based grid job scheduling model for an effective job scheduling in computational grid environment. The fuzzy logic-based grid job scheduling model measures resource efficiency of all grid resources by a fuzzy logic system based on diverse input parameters like CPU speed and network latency and divides resources into several groups by resource efficiency. And, the model allocates jobs to resources of a group with the highest resource efficiency. For performance evaluation, we implemented the fuzzy logic-based grid job scheduling model on the DEVS modeling and simulation environment and measured reduction rates of turnaround time, job loss, and communication messages in comparison with existing job scheduling models such as the random scheduling model and the MCT(Minimum Completion time) model. Experiment results that the proposed model is useful to improve the QoS of the grid job processing service.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.83-104
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• 2011

Mobile grid is a combination of grid computing and mobile computing to build grid systems in a wireless mobile environment. The development of network technology is assisting in realizing mobile grid. Mobile grid based on established grid infrastructures needs effective resource management and reliable job scheduling because mobile grid utilizes not only static grid resources but also dynamic grid resources with mobility. However, mobile devices are considered as unavailable resources in traditional grids. Mobile resources should be integrated into existing grid sites. Therefore, this paper presents a mobile grid middleware interconnecting existing grid infrastructures with mobile resources and a mobile service agent installed on the mobile resources. This paper also proposes a mobile resource reliability-based job scheduling model in order to overcome the unreliability of wireless mobile devices and guarantee stable and reliable job processing. In the proposed job scheduling model, the mobile service agent calculates the mobile resource reliability of each resource by using diverse reliability metrics and predicts it. The mobile grid middleware allocated jobs to mobile resources by predicted mobile resource reliability. We implemented a simulation model that simplifies various functions of the proposed job scheduling model by using the DEVS (Discrete Event System Specification) which is the formalism for modeling and analyzing a general system. We also conducted diverse experiments for performance evaluation. Experimental results demonstrate that the proposed model can assist in improving the performance of mobile grid in comparison with existing job scheduling models.

• Journal of the Korea Society for Simulation
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• v.24 no.2
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• pp.19-29
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• 2015

M&S techniques are utilized for various purposes on the national defense, and its importance is increasing than ever. For analyzing RAM (Reliability, Availability and Maintainability) of weapon system, using M&S techniques can be more effective and practical way than deterministic approach, because M&S approach can consider uncertain variables and various constraints in the ILS (Integrated Logistics support) field. For design of ILS M&S, we first set up a purpose of M&S, attributes of real system and other similar ILS M&S tool. Then, we convert real system into model which consists of mathematical formula and logical expression. In this thesis, we introduce modeling procedures of M&S that describes total life cycle of 'OO guided weapon system' and the contents proposed in this paper can provide references for developing other M&S tool.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.6
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• pp.617-627
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• 2022

Military training is an essential item for the fundamental problem of war. However, there has always been a problem that many resources are consumed, causing spatial and environmental pollution. The concepts of defense modeling and simulation and CGF(Computer Generated Force) using computer technology began to appear to improve this problem. The Naval Operations, Resources Analysis Model(NORAM) developed by the Republic of Korea Navy is also a DEVS(Discrete Event Simulation)-based naval virtual force analysis model. The current NORAM is a battle experiment conducted by an operator, and parameter values such as maneuver and armament operation for individual objects for each situation are evaluated. In spite of our research conducted evolutionary, supervised, reinforcement learning, in this paper, we introduce our design of a scenario creation model based on evolutionary learning using genetic algorithms. For verification, the NORAM is loaded with our model to analyze wartime engagements. Human-level tactical scenario creation capability is secured by automatically generating enemy tactical scenarios for human-designed Blue Army tactical scenarios.