• Fire Science and Engineering
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• v.22 no.1
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• pp.1-9
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• 2008

Carbon dioxide($CO_2$) agent, which has more safely extinguished fire than any other gaseous fire extinguishing agents, has been widely used in various protected enclosures and types of fires. According to the concept of performance-based design(PBD). $CO_2$ extinguishing system to be designed is needed to be evaluated for the performance of fire suppression with possible fire scenarios in an enclosure. In this paper, CFD simulations were carried out to study the effects of opening area on the performance of $CO_2$ extinguishing system and the flow characteristics in the machine room of $100m^3$ in which kerosene spill fire happened. This study showed that time of fire suppression increased linearly in proportion to the size of opening area, and fires for each model were completely suppressed prior to the end of discharge of $CO_2$ agent. It was shown that mass flow rate through opening was influenced by the combined effects of heat release rate of fire and discharge of $CO_2$ agent. After $CO_2$ agent was completely discharged, oxygen concentrations in enclosures for each model were lower than the limit concentration of combustion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1623-1631
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• 2016

There are many researches which analyze vulnerability for combat systems, have been progressing, and apply the analyzed result to reflect on design phase. Recently, there have been requirements for integrating the previous module based researches which conducted independently. In this paper, we propose an integrated vulnerability analysis method for the combat system considering characteristics of threats and protection performance of armors through an analysis of the advanced research. In addition, by applying the proposed method improves the existing hit probability analysis program and we are verified based on scenarios for improving survivability of PKM (Petrol Killer Medium) for vulnerability analysis confirmed the results. The proposed method improves reliability of vulnerability analysis by considering threats and defense ability. Also it able to satisfied with the integration requirements. Furthermore, we became buildup for the development of applied system and the method and integrated vulnerability analysis method for combat systems.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.112-113
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• 2012

본 논문에서는 실전적인 전투 훈련을 체험할 수 있는 육군 과학화 전투 훈련단의 시스템을 상용 이동통신망(LTE)을 기반으로 한 MTC(장비 또는 기계간의 통신)에 적용하여, 저비용이면서도 신뢰성있는 체계 모델을 제안하며 이를 통해 공군의 각 기지/부대 별 특성에 맞는 실전적 기지방호 훈련이 가능하게 되어 실질적인 전투 능력을 향상시킬 수 있을 것으로 기대한다.

• Fire Science and Engineering
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• v.21 no.4
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• pp.18-24
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• 2007

The purpose of this study is focussed on the numerical predictions of temperature distribution by radiation heat transfer in atrium fire using the field fire model and the CCRHT-3D code. This code uses standard $k-{\varepsilon}$ turbulent model with SIMPLE algorithm and weighted sum of gray gases model regrouping(WSGGM-RG). The WSGGM-RG calculates radiative properties on the reduced computational loads while reserving the accuracy. The numerical results show that lower temperature distributions on the wall and the top ceiling wall can be obtained by considering radiative heat transfer. The temperature on the top ceiling wall can be an important parameter in predicting the operating condition of the sprinkler head.

• Journal of the Korea Society for Simulation
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• v.30 no.2
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• pp.49-64
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• 2021

M&S techniques are widely used as scientific means to systematically develop response plans to chemical and biological (CB) hazards. However, while the theoretical area of hazard dispersion modeling has achieved remarkable practical results, the operational analysis area to simulate CB hazard response plans is still in an early stage. This paper presents a model to simulate CB hazard response plans such as detection, protection, and decontamination. First, we present a possible way to display high-fidelity hazard dispersion in a combat simulation model, taking into account weather and terrain conditions. We then develop an improved vulnerability model of the combat simulation model, in order to simulate CB damage of combat simulation entities based on other casualty prediction techniques. In addition, we implement tactical behavior task models that simulate CB hazard response plans such as detection, reconnaissance, protection, and decontamination. Finally, we explore its feasibility by analyzing contamination detection effects by distributed CB detectors and decontamination effects according to the size of the {contaminated, decontamination} unit. We expect that the proposed model will be partially utilized in disaster prevention and simulation training area as well as analysis of combat effectiveness analysis of CB protection system and its operational concepts in the military area.

• Journal of KIISE:Software and Applications
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• v.31 no.6
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• pp.773-783
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• 2004

This paper presents a method for real-time verification of Statecharts. Statecharts has been widely used for real-time reactive systems, and supports two time models: synchronous and asynchronous. However, existing real-time verification methods for them are incompatible with the asynchronous time model or increase state space by introducing new variables to the target models. We solved these problems by extending existing model checking algorithms. The extended algorithms can be used with both time models of Statecharts because they consider time increasing transitions only. In addition, they do not increase target state space since they count those transitions internally without additional variables. We extended an existing model checker, NuSMV, based on the proposed algorithms and conducted some experiments to show their advantage.

• Journal of Information Technology and Architecture
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• v.11 no.2
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• pp.157-173
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• 2014

As Air Base Defence, Anti-Aircraft Defence and Nuclear-Biological-Chemical Protection model considered as ground operation models in Republic of Korea Air Force are designed as the voice-centered system between participant nodes, there is a problem communicating accurately. In recent years, the military is developing a command and control capability using data communication technology to solve the problem. Therefore, this paper proposes new model to maximize efficiency of performance improvement through the Data Communication-based Future Air Base Defence Model. We refer to a research paper that is related existing and developed new model. and then we really experimented under WiBro Network that is constructed to Air Base for maintenance control. Based on the analysis and the test result of new Air Base Defence Model, we have concluded that the performance improvement effect is reached.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.48-53
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• 2007

The knowledge of the flash point of the mixtures is very important for prevention and protection of fire in the industrial field. The flash points for the water+2-propanol system were measured by using Tag open-cup apparatus(ASTM D1310-86). The experimental data were compared with the values calculated by the Raoult's law, the Van Laar equation and the NRTL(Non Random Two Liquids) equation. The calculated values based on the Van Laar and NRTL equations were found to be better than those based on the Raoult's law. It was concluded that Van Laar and NRTL equations were more effective than the Raoult' law at describing the activity coefficients for non-ideal solution such as the water+2-propanol system. And the predictive curve of the flash point prediction model based on the Van Law equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the NRTL equation.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.59-69
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• 2019

Smoke grenade is the most primary counteract of tank for its survival against threats, therefore a number of related researches and developments of M&S are being conducted. In this research, a vehicle-launched smoke grenade model is developed, that covers the essential engineering-level parameters, and also is applicable to engagement-level simulations because of its unheavy computational load. First of all, input parameters of the model were determined to include the principal factors from engineering to engagement level. In the model, smoke and LOS are modeled as simple figures, a disk and a line, so that the computational load is not as much as that of particle-model-based M&Ss. A test simulation is also carried out to analyze the effect of smoke grenade for a tank. This model is to be inserted into a basic tank model on AddSIM. The users of AddSIM will be able to simulate various scenarios including smoke grenades.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.459-466
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• 2018

Risk of radiation worker and radiation workplace are being mainly assessed by exposure dose. But, the radiation used in radiation workplace and the work environment are different. Because the nondestructive work environment varies depending on the work subject, the existence and nonexistence of shielding board, and so on. So, we need to consider the various factors in effective radiation protection aspect. We conducted a survey of radiation workers with over two years' experience in NDT workplace and heared the thoughts of experts. As a result, radiation source, exposure dose, current status of workplace management, workers with personel dosimetry problem and status of periodic regulatory inspection were chosen as main factors of radiation risk index model. Also, we primarily set weighting factors in order of importance based on questionnaires. Finally, we determined weighting factor for details of main factors through the professional advice. Therefore, we will be able to develop the radiation risk index model for assessing the risk of nondestructive test workplace based on main factors that are selected through this study.