• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.63-64
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• 2011

포물체란 중력이 작용하는 환경에서 어떤 속도로 던져진 물체를 뜻합니다. 예를 들자면, 박찬호 선수가 포수를 향하여 던진 야구공이라든지, 박세리 선수의 스윙으로 그린을 향하여 날아가고 있는 골프공, 그리고 목표물을 향하여 날아가고 있는 포탄은 모두 포물체입니다. 이 물체는 수직방향으로는 중력의 영향을 받고 공기의 저항을 무시한다면 수평방향으로는 힘을 받지 않기 때문에 포물선운동을 한다. 본 논문에서는 포물체의 운동을 이용하여 도로의 일부가 유실되어 없어진 곳을 실험 대상을 한다. 여기에서 속도가 일정하게 달리던 자동차가 유실된 도로의 가장자리를 넘어갔을 때 도로의 가장자리로에서 얼마나 멀리 가서 떨어지는지를 나타내었다.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.317-329
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• 2006

In this research, a questionnaire was developed to investigate high school students' viewpoints, originating from science history, on 'motion of on object', the subjects were seventy- five 10th grade students and sixty-five 11th grade students. Results found that the highest percentage among the types of 10th grade students' thoughts was related to the Middle Ages 'Impetus' viewpoints. Percentages of 11th grade students' thoughts were highest for Middle Ages and Newton views. These results provided proof that the development of student thoughts' based on science history' are consistent with school year. Furthermore, student thought regarding 'object motion' under the conditions of no force, vacuum, or air under a weightless stage were related to progressive viewpoints on science history. However, the percentage of thoughts related to earlier viewpoints were considerable. Student thoughts on parabolic motion, circle motion, and conservation amount of motion were found to be highly significant in similarity to the viewpoints of Galilei, Descartes, and Huygens; view cultivated before Newton. Consequently, this study determined that educational efficiency could be raised by providing historically more progressive views to cope with conflictory student thoughts-thoughts related to past views in science history.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.217-222
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• 2017

Any object located in the earth's gravitational field experiences a force in the direction of the center of the earth. In order to describe the motion of objects in the field, the solutions to a system of simultaneous vector kinematic equations need to be obtained. In the analysis of freely-falling objects, the reference direction +y is usually defined to be the downward direction. In the analysis of the motion of objects thrown upward, the reference direction +y is usually defined to be the upward direction. In the analysis of the motion of objects thrown downward, the reference direction +y is usually defined to be the downward direction. In this paper, we show that the choice of reference axis in either upward or direction gives the same results by adopting a scalar product of two vectors in solving the vector kinematic equations. It is rare to find other examples of using a scalar product of two vectors in solving vector kinematic equations describing the motion of objects. An application of this study is that we can arbitrarily choose the reference direction for objects moving in a horizontal direction, including projectile motions.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2471-2473
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• 2003

인간의 안구는 색과 모양을 식별하는 데에 관여하는 원추 세포와 물체의 명암을 구분하는 간상 세포로 구성되어지는 시세포를 가진다. 망막 위에 분포되어 있는 시세포들은 시축을 중심으로 각기 다른 밀도로 분포 되어 있다. 특히 광축과 만나는 중심 지역은 Fovea라고 하는 직경 1mm 정도의 작은 우물을 이루고 있는데 원추 세포들이 고해상도로 분포되어 있고 시신경과 일대일로 연결되어 있어 시각 처리의 중심이 된다. 특히, 글자나 물체를 인식하기 위해 인간은 대상물을 응시하여 대상물의 영상이 Fovca영역에 맺히도록 추적 운동을 계속한다. 본 논문에서는 인간의 눈과 유사한 망막 모델의 하나인 Log-polar Image를 이용한 물체 인식을 위해 물체를 Log-polar Image Plane의 중심에 위치시키기 위한 모멘텀(Momentum)기반 정합 알고리즘(Alignment Algorithm)을 제시한다. 이는 눈동자 운동이 가능한 능동형 시각 장치의 Tracking 및 Pursuit 동작 중에 밭생하는 추적 오차를 보상함으로써 운동 중에도 효과적인 물체 인식이 가능하게 한다. 또한, 물체를 Log-polar Image Plane의 중심에 위치시킴으로써 물체의 위치 이동, 회전이동 그리고 크기 변화에 무관하게 물체를 인식한 수 있음을 제시한다.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.104-117
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• 1991

When a body starts to move, the flow near the intersection point between a body and a free surface changes violently and rapidly in a very short initial time interval. This flow phenomena must be investigated whenever one treats the interaction between a body and a fluid, such as the motion of a floating body, sloshing in a tank, wave maker problem, entry of a body into a fluid etc.. Until Roberts(1987), it was widely accepted that a singularity exists at the intersection point. However, he showed that the singularity does not exist if a body moves non-impulsively. In this paper, an analytical solution cosistent for the case of impulsive motion of a body is obtained by including the effect of surface tension. From the characteristics of the newly obtained solution, a critical value associated with an oscillating phenomenon is found, and further more, it is shown that the oscillating phenomenon does not appear in the region where the distance form the intersection point is less than this critical value.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.25-31
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• 1989

Two-dimensional large-amplitude motions in regular harmonic wave are treated in time domain, by satisfying the exact body boundary condition and the linear free surface condition. For the present numerical calculation, the method of free-surface spectral representation with simple source distribution on the instantaneous body surface has been extended to include the effect of the incident wave. Calculations of the wave exciting force are performed for a submerged circular cylinder fixed or oscillating with large amplitude. Especially, nonlinear effects on the time-mean forces are studied in detail. It is shown that relative motion between the body and the fluid particle gives a significant effect on the lift and drift forces. Also, large-amplitude motion of a submerged circular cylinder and that of a floating Lewis-form cylinder are directly simulated in time domain. In the calculation results, some nonlinear effects are shown.

• Journal of KSNVE
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• v.14 no.4
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• pp.40-47
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• 2004

동역학에서 운동방정식의 유도를 위해 등장하는 방법들은 여러 가지가 있다. 그러나 모든 방법의 배경을 이루는 원리는 물론 뉴톤의 운동 법칙이며 이것은 하나의 질점에 대해서 힘과 질량 그리고 가속도 사이의 관계를 나타내는 법칙으로 물체의 운동이 빛의 속도에 비해 현저히 작은 값을 가질 때 상당히 정확하게 성립된다고 알려져 있다. (중략)

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.816-824
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• 2010

The forces applying to an object in the transferring pipe of waste are analyzed and the equation of motion is established in this paper. It is shown that the equation of motion becomes the 1st order non-linear differential equation. Using its general solution, the velocity of the object in the transferring pipe of waste can be expressed in the explicit form. Noting that the velocity of object is impact velocity to the elbow or curved part of the transferring pipe of waste, the kinetic energy of the object can be calculated and the necessary impact strength of inner wall is obtained. The velocity of object is also calculated and presented in the graphic forms with the condition of air velocity 30m/sec. The impact test of cast basalt tube is carried out by the free fall of a weight and the test results show that the impact strength of the cast basalt tube is sufficient to apply to protecting inner wall of the transferring pipe of waste.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.11B
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• pp.1920-1927
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• 2000

본 논문은 cepstral 필터를 이용하여 지적인 비주얼 센싱을 위한 카메라의 운동 제어법을 제안한다. 화상은 pursuit 운동을 위하여 물체의 옵티컬 플로우가 필요하고, vergence 운동을 위하여 양안시차 정보를 필요로 한다. 그러나, 화상정보에는 올바른 정보와 잘못된 정보가 존재하기 때문에 해의 올바른 시차를 선택해야 하는데, 옵티컬 플로우의 계산에서와 마찬가지로 템플리트 매칭을 이용하여 올바른 정보를 선택한다. 그리고, 화상 중의 하나를 3 조각으로 분할한 후 각각 cepstral 필터링에 의하여 양안시차를 검출한다. 본 논문은 saccade 운동, pursuit 운동, vergence 운동에 관한 제어 알고리즘을 제안하고, 실험에 의하여 알고리즘을 비교 및 분석한다.

• Korean Journal of Cognitive Science
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• v.10 no.3
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• pp.67-75
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• 1999

We investigated whether human could perceive the heading direction from the optic flow made from random dots and real images simulating the motion of the observer and objects. When an object moves across the focus of expansion(FOE) in random dot simulation. the observer perceived the focus of expansion biased toward the motion direction of the object. supporting the hypothesis that the direction repulsion is produced between the expansional and the horizontal planar motion components. With real image display observers tended to perceive one's heading direction biased toward the c center of the scene regardless of the direction and position of moving 0bcts. And it was observed that the deeper the depth of the background was the larger the judgment error was. These results suggest it is more likely that human depends on different cues than the optic flow when they perceive or judge one's heading direction in the real environment.