• 대한원격탐사학회지
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• 제26권3호
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• pp.297-304
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• 2010

Since the change in Doppler centroid according to moving targets brings alteration to the phase in azimuth differential signals of synthetic aperture radar (SAR) data, one can measure the velocity of the moving targets using this effect. In this study, we will investigate theoretically measuring the velocity of an object from azimuth differential signals by using range compressed data which is the interim outcome of treatment from the simulated SAR raw data of moving targets on the background of sea clutter. Also, it will provide evaluation for the elements that affect the estimation error of velocity from a single SAR sensor. By making RADARSAT-1 simulated image as a specific case, the research includes comparisons for the means of velocity measurement classified by the directions of movement in the four following cases. 1. A case of a single target without currents, 2. A case of a single target with tidal currents of 0.5 m/s, 1 m/s, and 3 m/s, 3. A case of two targets on a same azimuth line moving in a same direction and velocity, 4. A case of a single target contiguous to land where radar backscatter is strong. As a result, when two moving targets exist in SAR image outside the range of approximately 256 pixels, the velocity of the object can be measured with high accuracy. However, when other moving targets exist in the range of approximately 128 pixels or when the target was contiguous to the land of strong backscatter coefficient (NRCS: normalized radar cross section), the estimated velocity was in error by 10% at the maximum. This is because in the process of assuming the target's location, an error occurs due to the differential signals affected by other scatterers.

• Journal of the Optical Society of Korea
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• 제7권4호
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• pp.224-229
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• 2003

We report a novel optical delay line that can be implemented using only optical fiber and fiber devices without the need for any bulk-optic devices such as lens, prism, and moving mirror. The dispersive property of a chirped fiber Bragg grating (CFBG) is exploited to get the delay. The proposed delay line constitutes two identical CFBGs cascaded in the reverse order with one of them being strained. Analysis reveals that the small displacement or the strain applied on the CFBG is effectively amplified in the delay line by the ratio of the minimum resonant wavelength and the reflection bandwidth of the CFBG. The dispersion properties of the CFBG with and without the strain are analyzed in detail. The theoretical performance of the proposed delay line is also discussed. Applications of the proposed delay line are expected in the field of high-speed optical coherence tomograpy.

• 산업공학
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• 제6권1호
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• pp.99-112
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• 1993

This study deals with analysis of material from in Tube manufacturing line. This line is a multi product flow ship type production line, which consists of 5 steps of work station. Some work stations involve in unnecessary moving activities of workers and much work in-process storage due to the non-systematic material flow with respect to the different lot size production of multi-items. To improve productivity for this line, one alternative is considered such as grouping two work stations by using GT and JIT concepts. Also, feasibility analysis for this alternative is performed using and simulation model built by SIMAN IV simulation language.

• 산업공학
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• 제5권1호
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• pp.35-46
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• 1992

This paper deals with analysis of material handling system efficiency of a heat-exchanger manufacturing line. This line is a typical flow shop type assembly line which consists of 10 steps of assembly stations. Each station have one or two workers who assemble and move components for the job, and no special transporters for component's movement. Therfore, all the workers are involoved in unnecessary moving activities which decrease overall production efficiencies of the line. To improve productivities, production outputs and worker's job performances for this assembly line, the several alternatives are considered such as installing new conveyor lines and automatic guided vehicle(AGV) system. Analyzing economic feasibilities and responses of the system alternatives, an experimental simulation model is built suing SIMAN Ver. 3. 5 simulation language with CINEMA package for animation of the process flow. Through this animation process a vivid picturial analysis could performed on the process flow.

• 수산해양기술연구
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• 제45권1호
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• pp.14-21
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• 2009

This experimental study was carried out to obtain the base data for saving the man power in the fishing operation of largehead hairtail hand line by using the continuous type hand line system with a rotary device which could make a main line move automatically. In order to solve the twists and entangling on the main line happened during operating test, the resistance board was suspended at the end of the main line at sea. As the result, there were no problems of tangling and so on due to up and down moving of a main line. According to the control of a fixed angle of guide roller, it was possible to prevent the main line to be separated from a side roller and a guide roller. In addition, PVC tube between a guide roller and a side roller enabled a main line to be moved smoothly without any entanglement.

• 한국정보과학회논문지:시스템및이론
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• 제34권11호
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• pp.562-571
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• 2007

이차원 평면에 주어진 점들을 포함하면서 고정된 기울기를 갖는 직선 위에 중심을 갖는 k개의 디스크를 찾는 데, 최대 디스크의 반지름이 최소가 되는 디스크 집합을 계산하는 문제를 다룬다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.308-315
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• 2000

Headway calculation is a important mean to evaluate railway system performance. A accurate headway calculation can be needed to headway reducing being achieved line capacity increasing by regulating signals spacing without any line construction. This paper introduced the theories and algorithms of calculating headways on wayside, multi step, one step braking and moving block signalling systems and showed some results of headways.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.69.4-69
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• 2001

In this paper, we developed a Windows 98 version of off-line programming system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows 98´s graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.601-611
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• 2005

In this paper, an active vibration control of a tensioned, elastic, axially moving string is investigated. The dynamics of the translating string are described with a non-linear partial differential equation coupled with an ordinary differential equation. A right boundary control to suppress the transverse vibrations of the translating continuum is proposed. The control law is derived via the Lyapunov second method. The exponential stability of the closed-loop system is verified. The effectiveness of the proposed control law is simulated.

• 천문학회보
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• 제40권1호
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• pp.78.2-78.2
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• 2015

Powered by a supermassive black hole, active galactic nuclei (AGNs) are characterized by prominent emission lines including Blamer lines. The unification scheme of AGNs requires the existence of a thick molecular torus that may hide the broad emission line region. In this configuration, it is expected that the far UV radiation from the central engine can be Raman scattered by neutral hydrogen to reappear around Balmer lines which can be identified observationally with broad Balmer wings. Another mechanism that can form Balmer wings is considered by invoking a fast moving medium around the central engine. In this presentation, we produce Balmer wings that are formed through Raman scattering and also those expected from a fast moving emission flow. It is noted that Raman Balmer wings exhibit stronger red part whereas the opposite behavior is seen in the Balmer wings obtained from a fast moving emission flow.