• Journal of Information Processing Systems
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• 제2권2호
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• pp.124-129
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• 2006

With the explosive increase in the generation and utilization of spatiotemporal data sets, many research efforts have been focused on the efficient handling of the large volume of spatiotemporal sets. With the remarkable growth of ubiquitous computing technology, mining from the huge volume of spatiotemporal data sets is regarded as a core technology which can provide real world applications with intelligence. In this paper, we propose a 3-tier knowledge discovery framework for spatiotemporal data mining. This framework provides a foundation model not only to define the problem of spatiotemporal knowledge discovery but also to represent new knowledge and its relationships. Using the proposed knowledge discovery framework, we can easily formalize spatiotemporal data mining problems. The representation model is very useful in modeling the basic elements and the relationships between the objects in spatiotemporal data sets, information and knowledge.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.922-925
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• 2011

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian method widely used for the modeling fluid flows. Simulations of explosions require, besides the hydrodynamic equations, a realistic equation of state, an energy source term, and a set of chemical kinetic equations to follow the composition changes of the gas during the explosion. The performance of the hydrodynamic equations is investigated in the framework of the Sedov-Taylor blast-wave. The implementation of chemical kinetic equations and equation of state is studied with 1D detonation of TNT slab. Our results are compared to those from analytical and experimental studies.

• 한국IT서비스학회지
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• 제13권2호
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• pp.19-34
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• 2014

As the global smartphones market is growing at a brisk pace, their associated mobile applications are becoming increasingly ubiquitous in our daily life. The growth of mobile application business is explosive. Like other digital contents businesses, illegal downloads of copyrighted mobile applications become major obstacle in the future of the industry. In spite of anti-piracy efforts, the phenomenon has been getting worse. It is necessary to change the focus of current deterrence policies and strategies. This study investigates the factors influencing smartphone applications piracy behavior. For better understanding of illegal behavior, a research model of potential determinants for the piracy behavior is developed and empirically tested via path analysis using structural equation modeling. Findings show that social factors, beliefs concerning benefits from piracy, self-efficacy, and habit have significant effects on attitude toward smartphone application piracy. The result also shows perceived risks and facilitating conditions were not significantly related to their attitude. Implications for research and practice are discussed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.238-241
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• 2007

We present an innovative method of multi-physics application involving energetic materials. Energetic materials are related to reacting flows in extreme environments such as fires and explosions. They typically involve high pressure, hish temperature, strong non-linear shock waves, and high strain rate deformation of metals. We use an Eulerian methodology to address these problems. Our approach is naturally free from large deformation of materials that makes it suitable for high strain-rate multi-material interaction problems. Furthermore we eliminate the possible interface smearing by using the level sets. We have devised a new level set based tracking framework that can elegantly handle large gradients typically found in reacting gases and metals. We show several work-in-progress applications of our algorithm including the Taylor impact test, explosive venting and additional confined explosion problems of modem interest.

• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.113-138
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• 1999

Driven by the explosive expansion and acceptance of the Internet and its multimedia front-end, the Web, a new generation of the modeling and simulation tools have come up with the name of Web-Based Simulation (WBS). Most of WBS libraries inherit its powerful advantages from Java. However, there are cases where explicit specification of models or interface objects is more desirable than the black-box programs. This paper presents an XML-based DEVS (Discrete Event System Specification) markup language for sharing simulation models on the Web. DEVS provides a system-theoretic formalism for the language while XML supports platform-independent data access. This paper focuses on the design of such a language.

• ETRI Journal
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• 제32권1호
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• pp.22-32
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• 2010

The pervasive game environments have activated explosive growth of the Internet over recent decades. Thus, understanding Internet traffic characteristics and precise classification have become important issues in network management, resource provisioning, and game application development. Naturally, much attention has been given to analyzing and modeling game traffic. Little research, however, has been undertaken on the classification of game traffic. In this paper, we perform an interpretive traffic analysis of popular game applications at the transport layer and propose a new classification method based on a simple decision tree, called an alternative decision tree (ADT), which utilizes the statistical traffic characteristics of game applications. Experimental results show that ADT precisely classifies game traffic from other application traffic types with limited traffic features and a small number of packets, while maintaining low complexity by utilizing a simple decision tree.

• 한국시뮬레이션학회논문지
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• 제28권2호
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• pp.149-158
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• 2019

본 연구에서는 전장이나 재난 환경과 같은 인간이 투입되기 힘든 환경에서 인간을 대신하여 부상자 구조 및 위험물 처리 목적으로 개발된 구조로봇의 효율적 개발을 위한 통합 M&S 프레임워크를 소개한다. 개발된 통합 M&S 프레임워크는 계층화, 모듈화된 통합운동제어 소프트웨어의 구조에 기인하여 통합운동제어 소프트웨어 구조는 동일하게 이용하며 로봇 플랫폼을 시뮬레이션 프로그램으로 대체하여 SILS(Software-in-the-Loop Simulation) 개념의 M&S를 가능하게 하였다. 이를 활용하여 로봇 설계 및 로봇 제어 기술의 성능 검증 등의 개발 전 과정을 효율적으로 수행하였고, 비정형 환경에서의 원격 운용성 향상도 가져왔다. 통합 M&S 프레임워크의 적극적인 활용을 통해 구조로봇의 성공적인 개발 및 성능 확인을 완료하였으며, 구조로봇의 주요 기술 중 하나인 가변형상 제어를 통한 주행 안정화 기술 개발 과정에 적용된 통합 M&S 프레임워크의 사례를 통해 효용성을 확인한다.

• 한국지구과학회지
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• 제41권5호
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• pp.478-489
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• 2020

대기 압력 변동을 측정하는 인프라사운드 관측 기술을 통하여 원거리 지표폭발 사고를 분석하였다. 2019년 12월 24일 전남 광양시에서 발생한 2차례 폭발 사고에서 발생한 인프라사운드 신호가 151-435 km 거리에 위치하는 12개 음파 관측소에 기록되었다. 당시 인프라사운드는 북북서 방향의 성층권 바람에 의해 약 40 km 고도에서 굴절되어 같은 방향에 분포하는 관측소에 도달하였다. 반면, 약 10 km 고도에서는 강한 서풍의 영향으로 대류권 굴절 신호가 북동 및 동쪽 방향에 위치하는 관측소에 도달하는 등 방향에 따라 상이한 전파 경로를 보였다. 대기 유효음파속도구조와 포물선 방정식 모델링을 통해 전파 경로상의 투과손실을 계산하고 폭발 지점으로부터 기준거리에서의 초과압력을 추정하였다. 추정된 초과압력은 초과압력-폭발량 관계식에 적용함으로써, 두 차례의 폭발은 각각 14, 65 kg TNT 폭발 에너지에 상응하는 것으로 계산되었다. 1차 폭발 당시에 폭발 충격으로 부속물이 대기 중으로 비산하는 현상이 관측되었고, 폭발충격에 의한 파편 운동과 초과압력 간의 관계식으로 1차 폭발의 에너지는 약 49 kg 이하 TNT 폭발에 상응하는 것으로 계산되었다. 본 연구에서 제안한 폭발 에너지 추정 방법은 향후 다양한 원거리 폭발 에너지 계산에 활용이 가능하리라 본다. 향후 계산 결과의 신뢰도를 높이기 위해서는 대기 속도구조 불확실성에 대한 연구와 다양한 발파 자료를 통한 검증 연구가 필요하다.

• 한국추진공학회지
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• 제21권6호
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• pp.39-48
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• 2017

PMD 산업에서 주로 사용되는 ZPP와 $BKNO_3$에 대한 연소 모델링을 수행하였다. 구성방정식으로는 Saint Robert's law와 에너지보존식, 그리고 Noble-Abel 상태방정식을 사용하였다. 구축된 연소 모델과 실제 CBT에서 얻은 압력 결과데이터를 비교하였다. ZPP의 경우, 모델이 실험 결과와 유사한 압력곡선을 예측하였지만, $BKNO_3$는 챔버의 부피가 작을 때 모델이 실험보다 큰 최대압력을 도출하였다. 이에 대해 $BKNO_3$의 미연소성을 고려하였다.

• 한국군사과학기술학회지
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• 제22권1호
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• pp.20-26
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• 2019

In this paper, we propose measurement based numerical resistivity model for low energy exploding foil initiator (LEEFI) of electronic safety and arming device(ESAD). A resistivity model describes a behavior of variable resistance in LEEFI by firing current. The previous resistivity model was based on high energy detonator applications as explosive bridge wire and exploding foil initiator. Therefore, to estimate the voltage, current, and burst time of LEEFI, a resistivity model suitable for LEEFI is needed. For the modeling of resistivity of LEEFI, we propose a specific action based equation which represents a behavior of LEEFI when firing current is applied. To verify the proposed model, we analyze a firing current transmission path to obtain parasitic impedance. We experimentally verify that the proposed resistivity model offers precise estimation for the behavior of variable resistance in LEEFI.