• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.313-319
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• 1992

To investigate effects of water stress on apparent photosynthetic, transpiration rates, leaf orientation, yield and its related traits, four soybean varieties were planted on the Wagner pots in a plastic house covered with polyethylene film. As the light intensity and leaf temperature in a day increased, the movement of central leaflet in the second leaf of main stem occurred earlier than that of the lateral leaflet. The apparent photosynthetic rate of the central leaflet was higher than that of the lateral leaflet, but light intercept and leaf temperature of lateral leaflet were higher than those of the central leaflet. The apparent photosynthetic rate had highly positive correlation with the photon flux density, stomatal conductance and temperature, respectively. The photon flux density, stomatal conductance, transpiration and photosynthetic rates in the control were significantly higher than those in the water stress plot. The yield and its related traits in the water stress plot became decreased significantly in comparison with the control.

• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.435-444
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• 2006

Since artificial space objects are observable only in a short period of time and the characteristics of their motion is not exactly predictable, it is difficult to obtain both photometric and spectroscopic data by a set of observations. We have, therefore, designed a mount to load multi-optical instruments on the Kyung Hee University (KHU) satellite tracking and observation system for both photometric and spectroscopic observations of artificial space objects. In this paper, we have calculated the deformation of the remodeled mount using structural analyses for the loading of the multi-optical instruments. We have also deduced pointing errors of the mount occurring at tracking and observing artificial space objects. we have derived tracking reliably artificial space objects in our field of view and confirmed structural safety test of mount utilizing equivalent (von-mises) stress distribution.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.2
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• pp.55-59
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• 2010

Recently it is tried to use load control model for maneuver moving object. MIN design method proposed to solve control problem of nonlinear system using load concept. The Min design method shows direct method for finding control value on the load control model. In this paper, is shown realization free falling model using nonlinear load control model and analysis of load values acting falling object according to disturbance. And made a trajectory according to acting load values due to disturbance. This paper's result is able to be applied to design algorithm for improvement accuracy of MLRS, GPS air-to-surface missile(ASM) and returning spacecraft with nonlinear model predictive control.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.156-165
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• 2015

A survivability-analysis program has been developed to analyze the ground collision risk of atmospheric reentry objects, such the upper stages of a launch vehicle or satellites, which move at or near the orbital velocity. The aero-thermodynamic load during the free fall, the temperature variation due to thermal load, and the phase shift after reaching the melting point are integrated into the 3 degree-of-freedom trajectory simulation of the reentry objects to analyze the size and weight of its debris impacting the ground. The analysis results of the present method for simple-shaped objects are compared with the data predicted by similar codes developed by NASA and ESA. Also, the analysis for actual reentry orbital objects has been performed, of which results are compared with the measurement data.

• Journal of Science Education
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• v.42 no.2
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• pp.120-131
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• 2018

The purpose of this study is to examine the characteristics of science gifted students' understanding of friction acting on a rolling object, and to examine the implications of teaching methods that can be derived from them. For this purpose, 48 students in grade 3 students who take advanced physics classes at the science high school for the gifted were asked to answer three questions about the friction problems. As a result, students' responses were divided into three types: rule, none-rule, and calculation. In addition, students of the rule type have difficulty in reasoning about the friction by using friction rules. We believe that students will be able to reach a deeper understanding of friction if we teach them to correctly infer the direction of friction without using friction rules, along with a strategy to emphasize relative motion in contact.

• Korean Journal of Computational Design and Engineering
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• v.15 no.2
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• pp.106-114
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• 2010

The swept volume, the region of a moving object, is applied in many fields such as valid paths for motions of tools, visualization in robot paths and interference tests for parts assembling or disjointing. The shape of a swept volume depends on an generators computed with normal vectors of an object and velocity vectors of a motion. Although free-from surfaces are widely used to represent geometric models in CAD, computing the generators for a free-form object is a formidable task. Previous approaches exploit the closed form expressions of generators but limited to planer or quadric faces. In this paper, we propose the algorithm to compute swept volumes generated by free-form objects in screw motions. For the algorithm a tracing method is applied to the computation of generators. It considers curvatures of surfaces of an object to increase the computational accuracy. We implemented our algorithm in the CATIA V.5 environment to test the validity of our algorithm and to generate examples.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.694-696
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• 2005

연속된 장면이 아닌, 정지된 그림의 병렬적인 배열로 이루어지는 만화책은 다양한 특수 효과로 스틸이미지에서 동적인 효과를 이끌어 낸다. 그 특수 효과는 실제 물리적 이론에 기반하고 있지는 않지만, 독자에게 충분히 동적 운동 정보를 제공하는 특징을 느끼게 한다. 본 논문에서는 스틸이미지가 움직이고 있다고 느끼게 만드는, 만화기법의 동적효과를 조사하며 이 동적효과를 간단한 인자로 조절하는 방법을 제시한다. 그리고 동적 효과를 스틸이미지에 실제로 적용해본다. 본 연구의 결과로, 정지된 듯한 느낌을 주던 이미지에 동적인 느낌을 부여하게 되며, 추후 연구과제로서 비디오 영상에 대해 중요 장면을 추출하고 추출한 장면에 동적인 만화 기법을 적용시킨 만화를 만드는 연구를 진행시켜 나가고자 한다.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2485-2488
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• 2003

본 논문에서는 DSP를 이용하여 운동하는 물체의 회전량을 측정하는 실린더형 진동 자이로스코프(이하 자이로) 제어기를 개발하였다. 진동 자이로를 구동하기 위해서는 정밀 진동제어와 신호 처리와 같은 고급 제어 기술이 필요하다. 정밀진동제어는 진동 자이로를 구동하기 위해 필요한 핵심기술로써 기존의 PLL(phase-locked loop)방식은 외부환경에 민감하여 구현이 까다로울 뿐만 아니라 자이로 개개의 고유 진동수가 다르기 때문에 대량 생산에 어려움이 있었다. 또한 자이로 출력 신호로부터 회전량을 검출하기 위해서는 진폭과 당향성 검출의 본 회로뿐만 아니라 잡음 제거와 신호 증폭, 온도 보상과 같은 전처리 과정도 필요하다. 본 논문에서는 DSP를 통해 정밀 진동제어와 잡음 제거, 방향성 검출 등의 기능들을 구현하였으며 증폭과 진폭(회전량) 검출은 아날로그 회로를 이용하였다. 또 한 외부와의 인터페이스를 위해 D/A 회로를 설계하였고 이들을 실험을 통해 검증하였다.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.470-473
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• 1990

In this thesis, the recognition method of the movement of an 3D object is presented. The information about the movement of a 3D object is used to recognize the object. There are 2 kinds of movements which are translation and rotation. A difference picture is obtained from a sequence of images of a moving object or a scene which is taken by a monocular stationary observer. The 3D movement of an object is recognized by the Artificial Neural Network(ANN) using the difference picture.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.32-32
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• 1995

선박의 운항 상태를 재현하기 위한 시뮬레이터의 가시화 프로그램은 컴퓨터 그래픽 기법을 이용하여 사용자에게 실제로 선박을 운항하는 현실감을 제공하는 기능을 가져야 한다. 시뮬레이터를 위한 3차원 그래픽의 특성은 실제 상황을 실시간(real-time)으로 재현(15∼30Hz Update rates)해야 하는 기능이 요구되기 때문에 시점 변화에 빠른 그래픽 관련 계산 및 화면 표시에 필요한 시간 제약이 비교적 적은 CAD나 Animation용 3차원 그래픽 시스템과 달리, 시뮬레이션 대상 물체의 운동 상태를 정확히 표현하기 위한 빠른 3차원 그래픽 재현 기능이 매우 중요한 요소가 된다. 그러나 현실감 재현의 관점에서 광고 및 영화용 Animation시스템에서와 같은 Poto-Realistic한 현실감 재현 기능도 무시할 수 없는 요소이고, 현재 최신 컴퓨터 그래픽 기술의 발전과 고성능 그래픽 장비의 개발로 빠른 update rate의 현실감 있는 화면 재현이 가능해 지고 있고 이러한 기능의 요구가 점차 높아지고 있다.