• Title/Summary/Keyword: 가상원점

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Experimental Validation of the Radial Mapping Rule in Bounding Surface Plasticity Model (경계면 소성 모델의 방사 사상 법칙에 대한 실험적 검토)

  • Jung, Young-Hoon;Lee, Ju-Hyung
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.171-181
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    • 2013
  • The radial mapping rule in bounding surface model was experimentally investigated by analyzing the drained stress probe tests on Chicago clays. The experimental data obtained from 10 drained stress probe paths were analyzed to calculate the directions of the plastic strain increments. The anisotropic bounding surface model was adopted to represent a bounding yield surface which resides in the pre-consolidation yield stress of undisturbed clays. The projection origins were estimated by finding the interceptions of the straight lines passing through the current stress point and the imaginary yield stress point on the bounding surface. The results show that the projection origin is not fixed at a point but moves toward the direction of the stress probe path after it is established around the initial stress point.

Point Light Source Estimation from indoor environment from Light Probe (Light Probe를 이용한 제한된 실내 환경에 존재하는 점 광원 추정 기법)

  • Yoo, Jae-Doug;Park, Joung-Wook;Cho, Ji-Ho;Lee, K.H.
    • 한국HCI학회:학술대회논문집
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    • 2007.02a
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    • pp.494-499
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    • 2007
  • 실제 영상과 가상의 오브젝트 또는 가상의 환경에 오브젝트를 합성하는 경우 등 사실적인 합성을 결과를 얻기 위해서는 실제 환경과 같은 배경 영상의 정확한 광원 정보가 필요하다. 본 논문에서는 실내 환경을 배경으로 영상을 합성 하는 과정에 필요한 광원정보를 카메라와 Light Probe를 이용하여 촬영된 단일 영상으로부터 추정하는 기법을 제안한다. 실내에 존재하는 광원들은 정확한 위치정보를 알 수 없는 실외환경에서와 달리 제한된 공간의 원점으로부터 3차원 공간에 위치한 좌표로 나타낼 수 있다. 광원을 추정하기 위해 먼저 실내 공간에 반사도가 높은 Light Probe를 위치하고 디지털 카메라의 적정 노출을 이용하여 광원 추정에 사용할 영상을 획득한다. 광원으로 존재하는 오브젝트의 경우 짧은 노출시간에도 카메라의 영상에 획득된다. 그렇기 때문에 단일 영상에서 광원의 영역을 추정하기 위해 영상처리를 통해 노출 시간을 짧게 하여 촬영한 영상과 비슷하게 밝은 영역만 표현되도록 처리를 한다. 전 처리된 영상으로부터 밝은 영역과 어두운 영역으로 구분을 하고 밝은 영역으로부터 광원의 정보를 추정한다. 추정된 광원들은 실제 렌더링에 곧바로 적용이 가능하며, 이를 통해 배경에 적합한 렌더링 결과를 얻을 수 있다.

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Numerical Analysis of the Flow Field of Circular Nozzle Exit Region (원형노즐 출구 유동장의 수치해석)

  • Chung, Wui-Jun;Oh, Sang-Han;Son, Chang-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.6
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    • pp.13-18
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    • 2010
  • The programs of grid generation and flow analysis for the 3-D flow field. were developed. The finer results from numerical analysis could be obtained by using developed programs than those of the experimental data in the flow field of the circular nozzle exit region. Especially A virtual-origin of 3.2 times of nozzle diameter within three percent error inside from nozzle exit plane could be obtained.

Study on Reattachment in Axisymmetric Laminar Lifted Flames (축대칭 층류부상화염에서 재부착현상에 관한 연구)

  • Lee, Jong-Soo;Chung, Suk-Ho
    • Journal of the Korean Society of Combustion
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    • v.5 no.2
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    • pp.69-78
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    • 2000
  • Reattachment characteristics of laminar flames in partially premixed jets are studied for propane fuel mixed with air. As the flow rate decreases, liftoff height is decreased nonlinearly and the flame reattaches to a nozzle at a certain liftoff height. Using a jet theory by taking into account a virtual origin, it is predicted that flow velocity along a stoichiometric contour has a maximum value near nozzle. With this velocity characteristics, it is shown that reattachment mechanism can be explained by a balance between flame speed and flow velocity. Predicted displacement speeds at reattachment and liftoff agree qualitatively well with experimental findings.

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Analysis of the Flow of a Circular Nozzle using a slant Hot-Wire (단일 경사열선을 이용한 원형노즐의 유동해석)

  • Chung, Wui-Jun;Oh, Sang-Han
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.2
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    • pp.17-23
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    • 2009
  • The program using $C/C^{++}$ which could calculate 3-D velocities from data of the flowfield obtained by a slant hot-wire has been developed. The characteristic of the exit flowfield of a circular nozzle with a curved surface was investigated. From the result, the inward-flow was verified at adjacent layers near the boundary of the exit flowfield of a circular nozzle in Id and outward-flow was sensed gradually from down-flow of Id. Similarity of the nondimensional velocity profile properlly could be obtained except near Id and the virtual origin reasonably could be obtained.

An Investigation of Roughness Effects on 2-Dimensional Wall Attaching Offset Jet Flow (조도가 2차원 벽부착 제트유동에 미치는 영향에 관한 연구)

  • 윤순현;김대성;박승철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.219-230
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    • 1995
  • The flow characteristics of a two-dimensional offset jet issuing parallel to a rough wall is experimentally investigated by using a split film probe with the modified Stock's calibration method. The mean velocity and turbulent stresses profiles in the up and down-stream locations of the wall-attachment regions are measured and compared with those of the smooth wall attaching offset jet cases. It is found that the wall-attachment region on the rough wall is wider than on the smooth wall for the same offset height and the jet speed. The position of the maximum velocity point is farther away from the wall than that for the smooth wall case because of the thick wall boundary layer established by the surface roughness. It is concluded that the roughness of the wall accelerates the relaxation process to a redeveloped plane wall jet and produces a quite different turbulent diffusion behavior especially near the wall from comparing with the smooth plane wall jet turbulence.

NUMERICAL ANALYSIS FOR 2-D FREE JET FLOW BY SMAC SCHEME (SMAC법에 의한 2차원 자유분류의 수치해석)

  • Jung, S.H.;An, Y.J.;Shin, B.R.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.298-302
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    • 2009
  • Numerical analysis of two dimensional incompressible laminar free jet flow was carried out by using finite difference SMAC scheme. Flow characteristics of free jet flow such as jet width, similarity of jet velocity and hypothetical origin were investigated for different Reynolds numbers of Re=30 and 100. The reliability of predictions were confirmed by comparison with exact solution. Non-dimensional velocity distribution showed similarity of jet flow velocity after initial region. In the region of laminar flow, the location of hypothetical origin becomes more distant with Reynolds number.

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An Analytical Approach to One-Person-Library (ONE-PERSON-LIBRARY의 의미론적 해석)

  • Chung, Jun-Min
    • Journal of the Korean Society for Library and Information Science
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    • v.47 no.3
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    • pp.25-47
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    • 2013
  • The cognitive approaches on library and librarianship are being questioned. These are led from what the identity of the librarian is and from what the library is. This revealed that the perception of the library should not be acquired by interpreting its appearances but by interfering its nature. In conclusion, the information service is disclosed virtually as the essence of the library. On realizing the library virtually, even a person could be entitled as the library on the underlying assumption of information service (one-person-library).

Extraction or gaze point on display based on EOG for general paralysis patient (전신마비 환자를 위한 EOG 기반 디스플레이 상의 응시 좌표 산출)

  • Lee, D.H.;Yu, J.H.;Kim, D.H.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.5 no.1
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    • pp.87-93
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    • 2011
  • This paper proposes a method for extraction of the gaze point on display using EOG(Electrooculography) signal. Based on the linear property of EOG signal, the proposed method corrects scaling difference, rotation difference and origin difference between coordinate of using EOG signal and coordinate on display, without adjustment using the head movement. The performance of the proposed method was evaluated by measuring the difference between extracted gaze point and displayed circle point on the monitor with 1680*1050 resolution. Experimental results show that the average distance errors at the gaze points are 3%(56pixel) on x-axis, 4%(47pixel) on y-axis, respectively. This method can be used to human computer interface of pointing device for general paralysis patients or HCI for VR game application.

Emotion Adjustment Method for Diverse Expressions of Same Emotion Depending on Each Character's Characteristics (캐릭터 성격에 따른 동일 감정 표현의 다양화를 위한 감정 조정 방안)

  • Lee, Chang-Sook;Um, Ky-Hyun;Cho, Kyung-Eun
    • Journal of Korea Game Society
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    • v.10 no.2
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    • pp.37-47
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    • 2010
  • Along with language, emotion is an effective means of expression. By expressing our emotions as well as speaking language, we can deliver our message better. Because each person expresses the same emotion differently, this expression is a useful gauge to measure an individual personality. To avoid monotonous emotional expression from virtual characters, therefore, it is necessary to adjust the creation and deletion of the same emotion depending on each character's personality. This paper has attempted to define personality characteristics that have an impact on each emotion and propose a method to adjust the emotions. Furthermore, the relationship between particular emotion and personality characteristics has been defined by matching the significance of specified personality characteristics with the lexical meaning. In addition, using the Raw Score, the weighted value which is necessary for the adjustment, continuance and deletion of each emotion has been defined. Then, emotion was properly adjusted. When the same emotion was adjusted using actual personality test data, different results have been observed by personality. This paper has been conducted using NEO Personality Inventory (NEO-PI) which consisted of 5 broad domains and 30 sub domains.