• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.766-767
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• 2015

전자기 관련 제품에서 제작공차에 의한 성능변동의 확률론적 분포특성을 효율적으로 예측하기 위해 성능 모멘트 적분법을 도입하였다. 제안된 기법을 검증하기 위해 간단한 수학예제와 스피커 모델의 폴피스 사이 공극의 평균자속 밀도에 대한 확률론적 분포특성 예측을 수행하고, 이를 기존 확률론적 분포특성 예측 기법과 비교하였다. 또한 몬테카를로 수치모사법을 이용하여 도출된 성능의 확률론적 분포특성 예측 값을 재계산 후 비교함으로써 제안된 기법의 정밀도를 검증하였다.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.51-58
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• 2000

Recently, the J/T analysis based on elastic-plastic finite element analysis is popularly used in the nuclear industry to assess the integrity of a cracked pipe. The objective of this paper is to evaluate the effect of stress-strain curve for weld metal, variation of crack incremental length(${\delta}a$), and crack face pressure on the J/T analysis result. For this purpose, a parametric analysis was performed and the results calculated from finite element analysis were compared with those from the piping experimental data(stainless steel weldment pipe with circumferential through-wall crack). The numerical result using base metal material property is in agreement with the experimental one and the maximum load is decreased as the ${\delta}a$ for J/T analysis is increased.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.459-463
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• 2001

정보기술의 발달과 함께 정보시스템을 보호하기 위한 정보보안관리문제는 모든 기관 및 조직에서 반드시 짚고 가야 하며, 조직 전반에 걸쳐 표준적인 관리지침을 통해 포괄적으로 검토되어야 하는 문제로 대두되고 있다. 그러나, 현행 국방관련조직은 전반적으로 보안관리방법과 관리모델이 정립되지 않은 실정이므로 정보보안관리를 위한 표준관리 지침이 요구된다. 이에 본 논문은 정보시스템을 운영하는 조직 전반의 보안상태를 평가하는데 유용한 방법론인 정보보안관리규격(BS7799)을 적용함으로서 전사적인 관점에서의 국방정보체계 정보보안관리모델을 제안하고자 한다.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.312-319
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• 2005

For real time dynamic simulation, two different subsystem synthesis methods with independent generalized coordinates have been developed and compared. In each formulation, the subsystem equations of motion are generated in terms of independent generalized coordinates. The first formulation is based on the relative Cartesian coordinates with respect to moving subsystem base body. The second formulation is based on the relative joint coordinates using recursive formulation. Computational efficiency of the formulations has been compared theoretically by the arithmetic operational counts. In order to verify real-time capability of the formulations, bump run simulations of a quarter car model with SLA suspension subsystem have been carried out to measure the actual CPU time.

• Korean Journal of Computational Design and Engineering
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• v.20 no.4
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• pp.328-336
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• 2015

We proposed a methodology to automatically extract the requirements from the documents and check the consistency and traceability among them. The documents include not only text but also PDF or image files. We also suggest a method to visualize the result with maps, numbers, and graphs. By comparing the results with those of manual reviews from experts, we show that it is necessary to use knowledge-based method in future instead of the wordbased method for improving the reliability. The results can be applied effectively for already existing documents.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.90-96
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• 2013

During the cold forming, due to high working pressure acting on the die surface, failure mechanics must be considered before die design. One of the main reasons of die failure in industrial application of metal forming technologies is wear. Die wear affects the tolerances of formed parts, metal flow and costs of process etc. The only way to control these failures is to develop methods which allow prediction of die wear and which are suited to be used in the design state in order to optimize the process. In this paper, the wear experiments to obtain the wear coefficients and the upsetting processes was accomplished to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes was accomplished by the rigid-plastic finite element method. The result from the deformation analysis was used to analyse the die wear during the processes and the predicted die wear profiles were compared with the measured die wear profiles.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.63-65
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• 2012

최근 군사 모의 소프트웨어는 사용자의 다양한 요구 변화에 빠르게 적응하기 위해 컴포넌트를 조합하여 구성하는 방법으로 개발되고 있다. 이와 같은 소프트웨어에서 부대의 과업을 달성하기 위해 사용자의 관여 없이 부대구성원(부대원 또는 예하부대)의 전술적 행위(협업)를 모의하는 기술은 대규모의 군사 모의를 가능하게 하는 중요한 기술 중 하나이다. 부대 구성원의 협업을 모델링하고 구현하는 기술은 사용자(모의 부대장)로 하여금 부대구성원의 세부적인 제어를 요구하지 않고 자신이 제어하는 부대에 할당된 임무 달성에 집중시키는 등의 이점을 제공한다. 본 연구를 통해 우리는 군 도메인에서 사용하고 있는 OneSAF와 FLAMES, VR-Forces 등의 컴포넌트 기반의 모의 소프트웨어를 분석하고, 이들 소프트웨어에서 협업 모델의 위치를 설명한다. 다음으로 역할 개념을 기반으로 부대구성원들의 협업 모델을 제안한다. 본 연구에서는 프로토타입의 개발을 통해 제안 모델의 적용 가능성을 검증한다.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.425-436
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• 2015

This paper presents the procedures used for estimating the stability and control derivatives of a general aviation canard aircraft from flight data. The maximum likelihood estimation method which accounts for both process and measurement noise was used for the flight data analysis of a four seat canard aircraft, the Firefly. Without relying on the parameter estimation method, several aerodynamic derivatives were obtained by analyzing the steady state flight data. A wind tunnel test, a flight test of a 1/4 scaled remotely controlled model aircraft, and the prediction of aerodynamic coefficients using the USAF Stability and Control Digital Data Compendium (DATCOM), Advanced Aircraft Analysis (AAA), and Computer Fluid Dynamics (CFD) were performed during the development phase of the Firefly and the results were compared with flight determined derivatives of a full scaled flight prototype. A correlation between the results from each method could be used for the design of the canard aircraft as well as for building the aerodynamic database.

• The Journal of Korea Robotics Society
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• v.9 no.2
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• pp.117-123
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• 2014

Localization is one of the essential tasks necessary to achieve autonomous navigation of a mobile robot. One such localization technique, Monte Carlo Localization (MCL) is often applied to a digital surface model. However, there are differences between range data from laser rangefinders and the data predicted using a map. In this study, commonly observed from air and ground (COAG) features and candidate selection based on the shape of sensor data are incorporated to improve localization accuracy. COAG features are used to classify points consistent with both the range sensor data and the predicted data, and the sample candidates are classified according to their shape constructed from sensor data. Comparisons of local tracking and global localization accuracy show the improved accuracy of the proposed method over conventional methods.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.412-419
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• 2016

The firing noise produced at artillery test range or military training ground is impulsive burst noise which energy is generated within tens of milliseconds and distributed an isolated burst of sound energy separated to one by one noise. The long range propagation of this noise is affected by a caliber of gun, amount of propellant, distance between source and receiver, ground and meteorological condition. In this paper, main influence parameters have been described based on experimental analysis of measured data. It is considered that this analysis result can be used as useful materials for study of effective firing noise management and development of propagation model.