• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.63-66
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• 2009

본 논문에서는 트림영역이 있는 NURBS 평면을 등기하 해석할 수 있는 방법을 제시한다. 기존 등기하 해석법으로 트림 NURBS 곡면을 해석하기 위해서는 해석 도메인이 여러 개의 사각형 패치로 분할되어있어야 한다. 그러나 본 연구에서 제안한 방법은 CAD에서 제공하는 트림곡선의 정보를 해석에 직접 사용할 수 있기 때문에 CAD 모델을 별도로 재구성해야하는 번거로움이 없다. NURBS 곡선 투영법을 이용하여 트림되는 요소를 찾고, 트림된 요소는 쿼드트리 분할법과 NEFEM에서 사용된 적분방법을 동시에 고려하면 어떤 경우의 트림 요소라도 적분이 가능하다. 다양한 수치 예제를 통하여 제안한 해석 방법을 검증하고, 기존의 등기하해석법으로 해석하기 어려운 다수의 트림영역이 존재하는 NURBS 평면을 해석하여 본 방법의 유용성을 검토한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.863-871
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• 2013

Flow characteristics of velocity-control trim in a valve is investigated numerically with high pressure drop. A basic trim widely used for a valve in domestic powerplants is selected and designed for a baseline of velocity-control trim. The numerical analysis is focused on flow rate and cavitation with the basic trim. For a condition of high-pressure drop, pressure drop between inlet and outlet and fluid temperature are selected to be 18.1 MPa and $160^{\circ}C$, respectively, which are typical ones considering operating conditions adopted in powerplants. With this baseline model and condition, design changes are made for improvement of flow rate and cavitation phenomenon. For re-design, trim is divided into three zones in radial direction and design parameters of flow area, stage, and flow direction are considered in each zone. With these combined parameters applied to each zone, 4 models with design changes are proposed and their flow rates and cavitation areas are investigated. From comparison with those in the baseline model of a basic trim, proposed models show better performance in both flow rate and cavitation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.393-396
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• 2010

In this paper the process of transmitting images signal restore to image corrupted by impulse noise proposed alpha-trimmed mean filter. the proposed filter first identifies the noise pixels using the morphological noise detector and then removes the detected impulse noise using the alpha-trimmed mean filter. these proposed filter can realize the accurate noise detection and it can remove impulse noise effectively while preserving edge region in the image very well. Through the simulation, we compared with the existing methods and capabilties.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.983-991
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• 2019

This study aims to analyze movies which contain various stories according to the size of their shots. To achieve this, it is needed to classify dataset according to the shot size, such as extreme close-up shots, close-up shots, medium shots, full shots, and long shots. However, a typical video storytelling is mainly composed of close-up shots, medium shots, full shots, and long shots, it is not an easy task to construct an appropriate dataset for extreme close-up shots. To solve this, we propose an image cropping method based on the region of interest (ROI) detection. In this paper, we use the face detection and saliency detection to estimate the ROI. By cropping the ROI of close-up images, we generate extreme close-up images. The dataset which is enriched by proposed method is utilized to construct a model for classifying shots based on its size. The study can help to analyze the emotional changes of characters in video stories and to predict how the composition of the story changes over time. If AI is used more actively in the future in entertainment fields, it is expected to affect the automatic adjustment and creation of characters, dialogue, and image editing.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.706-711
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• 2015

The fighter aircraft uses several different loading configurations for air-to-surface and air-to-air combat missions. To maintain wings-level flight with an asymmetric weapon configuration, a pilot controls a roll trim system. However, it is difficult to apply an accurate roll trim input for wings-level flight in the actual flight under disturbance. The inaccurate roll trim input degrades the performance of the roll autopilot system. In this paper, to solve this problem, an integrator was additionally designed in the command part of the roll autopilot system. The initial transient response was improved by scheduling the limiter to restrict the roll attitude error. As a result of the evaluation of the simulation for the designed flight control law, the roll attitude following performance was found to be improved in the autopilot system operation under the inaccurate roll trim condition.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.3
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• pp.465-481
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• 2014

This study is about an apparel industry in Guro-Gasan where is growing up to the one of the apparel industry cluster beyond an agglomeration in Seoul. The purpose of this study is twofold: (1) to define industrial functions and roles of Guro-Gasan in a value chain of the apparel industry; and (2) to understand whether an industrial cluster is built on the local networks. This study reviewed formation and transitions of its local industries and industrial size, characteristics, spatial distribution and spatial properties using GIS analysis and field surveys. Through in-depth interviews, it analyzed the production system and spatial dispersion of the value chain to understand its functions and roles.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.10-10
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• 2003

EXAES 분석은 Normalized absorption spectrum의 Fourier transform을 기초로 분석되고 있기 때문에 EXAFS 분석에서의 R-space 분해능은 흡수 스펙트림에서 넓은 에너지 영역에서 EXAFS 신호가 얻어질수록 증가된다. 그러나 EXAFS 스펙트럼의 신호는 에너지가 증가함에 따라 지수적으로 감소하기 때문에 매우 한정된 범위의 스펙트럼이 측정되고 따라서 EXAFS 분석은 R-space에서의 분해능은 매우 제한적이다. 이것을 극복하기 위하여 신호 처리에서 Regularization방법을 도입하여 R-space에서의 분해능이 기존의 EXAES보다 현저히 증가될수 있음을 확인하였다.

• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.134-140
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• 2016

An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.35-41
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• 2006

This paper proposes an algorithm for switching LQ(Linear Quadratic) controllers designed at each flight envelope without a bump phenomenon. This algorithm is derived to apply to LQ controller more easily than existing implementation algorithm and is proposed to consider trim points of nonlinear models, which is adequate to real applications. This paper exemplifies the control performance improvement via simulations applied to LQ control of a supersonic test aircraft as a benchmark problem to test the proposed algorithm performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.8 no.2
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• pp.67-80
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• 1998

논문에서는 프레임릴레이 프로토콜을 사용하는 암호 통신 시스템에 적합한 키 스트림 동기 방식을 제안하였다. 제안된 주소영역의 확장 비트를 이용한 키 스트림 동기 방식은 단위 측정 시간 동안 측정된 프레임릴레이 프로토콜의 주소영역의 확장 비트 정보와 플래그 패턴의 수신률을 이용하여 문턱값보다 적은 경우에 동기 신호와 세션 키를 전송하므로써 종래의 주기적인 동기 방식에서 전송 효율성 저하와 주기적인 상이한 세션 키 발생, 다음 주김까지 동기 이탈 상태로 인한 오류 확산 등의 단점을 해결하였다. 제안된 알고리즘을 데이터 링크 계층의 처리기능을 최소화하여 패킷 망의 고속화가 가능하도록 설계된 프레임릴레이 프로토콜에서 서비스되는 동기식 스트림 암호 통신 시스템에 적용하여 slip rate $10^{-7}$의 환경에서 주기가 Isec인 주기적인 동기 방식에서 요구되는 9.6*10/ sup 6/비트에 비해 6.4*$10^{5}$비트가 소요됨으로써 전송율 측면에서의 성능 향상과 오복호율과 오복호율과 오복호 데이터 비트 측면에서 성능 향상을 얻었다.다.