• 한국군사과학기술학회지
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• 제13권3호
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• pp.453-460
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• 2010

For high quality image acquisition, compensating air-vehicle motion is essential for airborne SAR system. This paper describes a timing control based motion compensation method for airborne SAR system. Efficient timing control is critical for SAR system since it maintains many timing signals and timing setting for the signals should be updated frequently. This paper proposes Timing Cluster method as an efficient means for timing control of SAR system. Moreover, this paper suggests a simple and efficient method to compensate air-vehicle motion based on the Timing Cluster method. Timing Cluster method enables SAR system to control the timing in a timing noncritical way just maintaining little amount of information.

• 대한방사선기술학회지:방사선기술과학
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• 제16권2호
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• pp.19-26
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• 1993

Magnetic Resonance Image represents three-dimensional diagnostic imaging technique using both nuclear magnetic resonance phenomenon and computer. Compared with computed tomography (CT), MRI have advantages harmless to patient's body, three-dimensional image with high resolution and disadvantages long data acquisition time because of long T1 relaxation time, relatively low signal to noise ratio, high cost of setting, also. As physiologic motion of tissue results in motion ghost in MRI, high 2.0Tesla make improve low signal to noise ratio. This study have aim to improve image quality with controling motion ghost of tissue. Supposing a moving pixel in constant frequency, one pixel make two ghosts which are same size and different anti-phase. So, this study will show adjust parameter on locational control of motion ghost. Author made moving phantom replaced by respiratory movement of human, researched change of motion frequency, FOV by location shift, and them decided optimal FOV (field of view). The results are as follows: 1. The frequency content of the motion determines how far the image always appear in phase-encoding direction, the morphology of the ghost image is characteristic of the direction of the motion and its amplitude. 2. Double FOV of fixed signal object for locational control of motion ghost is recommended. Decreasement of spatial resolution by increasing FOV can compensate on increasing of matrix in spite of scan time increasement.

• 영어어문교육
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• 제12권4호
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• pp.31-68
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• 2006

The present research investigates the acquisition of the English locative alternation by Korean EFL learners, which poses a learnability paradox, taking Pinker's framework of learnability theory as its basis. It addresses two questions (1) how lexical knowledge is represented initially and at different levels of interlanguage development and (2) what kinds of difficulty Korean learners find in the acquisition of English locative verbs and their constructions. Three groups of learners at different proficiency levels with a control group of English native speakers are examined by two instruments: elicited production task and grammaticality judgment task. According to different levels of proficiency, the learners exhibit gradual sensitivity to a change-of-state meaning and obtain complete perception of the meanings of locative verbs (manner-of-motion and change-of-state) and their constructions. Overgeneralization errors are observed in their performance. The errors are due to misinterpretations of particular lexical items in conjunction with the universal linking rules. More fundamental cause of difficulty is accounted for by partial use of learning mechanisms, caused by insufficient L2 input.

• 한국컴퓨터정보학회논문지
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• 제22권7호
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• pp.39-45
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• 2017

In this paper, we propose three compensation methods to solve problems in high-resolution airborne infrared camera and to improve long-range target information acquisition performance. First, image motion and temporal noise reduction technique which is caused by atmospheric turbulence. Second, thermal blurring image correction technique by imperfect performance of NUC(Non Uniformity Correction) or raising the internal temperature of the camera. Finally, DRC(Dynamic Range Compression) and flicker removing technique of 14bits HDR(High Dynamic Range) infrared image. Through this study, we designed techniques to improve the acquisition performance of long-range target information of high-resolution airborne infrared camera, and compared and analyzed the performance improvement result with implemented images.

• 복식문화연구
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• 제8권4호
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• pp.587-601
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• 2000

The purpose of this study : 1. The total 56 range measurements of active dynamic motion of 40 subjects (20's and 30's) were measured using 3-D dynamic motion analysis system. 2. Various comparisons were performed for the right and left side, male, age groups (20's, 30's, and 40's ∼ 60's) using previous studies. The results were compared with the other studies in the aspects of age. In this study, the 3-D motion analysis system based on photogrammetry was established and used to analyze the human's motion and posture. The system consists of VICON 140, data acquisition system, and data analysis program (KRISSMAS). The result of this study were as follows : 1. Comparing 20's with 30's the result shows that 30's have larger ROM at some joints, which is inconsistent with the previous result. The reason is that female subjects in 20's were improperly sampled according to the representatives of anthropometry characteristics. 2. There are significant differences in some joints related with age. 20's male subjects have more flexible joints in the neck while 30's male subjects have more flexibility in their shoulder joint and elbow joint. But most of the significances were not high (p〈0.05). The prediction that the right side of Korean bodies would be more flexible was not a good hypothesis. And the joints flexibilities are not correlated with Rohrer's Index.

• 복식문화연구
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• 제8권5호
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• pp.741-753
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• 2000

The purpose of this study : 1. The total 24 range measurements of active dynamic motion of 40 subjects(20's and 30's, and 40's∼60's) using previous studies. The results were compared with the other studies in the aspects of age. In this study, The 3-D motion analysis system consists of VICON 140, data acquisition system, and data analysis program called by KRISSMAS. VICON 140 is dynamic motion analyzer, and KRISSMAS is a program developed for analysis of the data captured from the VICON. The results of this study were as follows : 1. Comparing 20's∼30's and 40's∼60's the result shows that 40's∼60's have smaller ROM at the most joints(Thoratic and Lumber, Hip Joint, Knee Joint, Ankle Joint), which is inconsistent with the previous result. The reason is that most investigations were carried out using traditional measurement equipments, which have encountered difficulty in quantifying the exact motion of the body. 2. There are no significant mean difference between the right and the left side. Most of the significances were not high(〉0.05).

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2005년도 제30회 춘계학술대회
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• pp.59-63
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• 2005

호흡 움직임은 종양에 대한 방사선치료의 부정확한 방사선조사가 유도되도록 복부 및 흉부에서 움직임을 야기한다. 그러므로 치료시 이러한 움직임에 대한 정확한 계산은 정상조직에는 저 선량을 조사되도록 CTV의 마진을 줄일 수 있고 방사선치료에 발생되는 부작용을 줄일 수 있다. Intrafraction motion을 고려하는 기술로는 호흡 멈춤, 호흡동조, 4차원 또는 종양추적 기술이 있다. 호흡동조 방법은 환자의 호흡 신호가 호흡주기의 일정한 범위에 위치할 때 주기적으로 빔을 조사하고 그 범위를 벗어날 때는 빔을 조사하지 않는 방법이다. 이러한 기술은 내부장기 움직임과 상관관계가 있는 호흡 움직임 신호의 획득이 요구된다. 호흡동조 방사선치료를 위한 예비연구로 본 연구자들은 호흡 움직임 신호 측정을 수행하였다. 환자의 호흡 움직임 신호 측정을 위해서, 호흡측정시스템을 3 가지 센서, 4 채널 데이터 획득 시스템, 신호처리용 컴퓨터로 구성하였다. 2명의 환자를 대상으로 본 연구자들은 호흡측정시스템을 가지고 호흡주기 및 파형을 평가하였다. 그 결과 호흡주기는 시간의 함수에 따라 일반적으로 정확한 대칭 형태는 아니지만 주기적인 형태로 측정되었다. 호흡측정 시스템은 기대했던 만큼 환자의 호흡을 잘 추적하였으며 실험에 적용하기 위해 쉽게 컨트롤 할 수 있었다.

• 한국전자파학회논문지
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• 제29권9호
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• pp.707-721
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• 2018

본 논문에는 30 cm 해상도를 갖는 소형 SAR(Synthetic Aperture Radar) 시스템 개발 결과를 소개하고, RAW 데이터 기반의 도플러 파라미터 추정 및 요동 보상 신호처리 알고리즘을 제시한다. 송수신 채널이 각각 2개이기 때문에 다중 편파 및 간섭계 영상 확보가 가능하며, 차량 탑재 시험을 통하여 다중 편파 SAR 데이터 획득 및 신호 처리 결과를 제시하였다. 플랫폼의 요동에 의한 잔여 위상 오차를 보상하는 알고리즘을 적용하였으며, 실제 차량 탑재 시험을 통하여 요동 보상에 따른 개선된 성능 결과를 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.17-21
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• 1989

6-DOE simulator system is designed to real-time processing for motion control, data acquisition, image generation and image processing etc.. In this paper, we introduce hardware and software design technologies for distributed processing, event-trapping, system monitoring and time scheduling procedure in 6-DOF simulator system design.

• Wind and Structures
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• 제24권4호
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• pp.333-350
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• 2017

Differing from the fixed-type, the dynamic motion of floating-type offshore wind turbines is very sensitive to wind and wave excitations. Thus, the sensing and monitoring of its motion is important to evaluate the dynamic responses to the external excitation. In this context, a monitoring system for sensing and processing the wind-induced dynamic motion of spar-type floating offshore wind turbine is developed in this study. It is developed by integrating a 1/00 scale model of 2.5MW spar-type floating offshore wind turbine, water basin equipped with the wind generator, sensing and data acquisition systems, real-time CompactRIO controller and monitoring program. The scale model with the upper rotatable blades is installed within the basin by means of three mooring lines, and its translational and rotational motions are detected by 3-axis inclinometer and accelerometers and gyroscope. The detected motion signals are processed using a real-time controller CompactRIO to calculate the acceleration and tilting angle of nacelle and the attitude of floating platform. The developed monitoring system is demonstrated and validated by measuring and evaluating the time histories and trajectories of nacelle and platform motions for three different wind velocities and for eight different fairlead positions.