• Imaging Science in Dentistry
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• 제31권4호
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• pp.205-207
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• 2001

Purpose : The aim of present study is to estimate the relationship among reference lines used for taking the extraoral radiography and panoramic radiography. Materials and Methods: Lateral cephalographs of 40 adults, aged 22 to 30 years were taken. Angles between reference lines (Frankfort line, canthomeatal line, infraorbitomeatal line, and occlusal plane) were measured. Results: Angles between Frankfort line and canthomeatal line, Frankfort line and infraorbitomeatal line, Frankfort line and occlusal plane, canthomeatal line and infraorbitomeatal line, canthomeatal line and occlusal plane, and infraorbitomeatal line and occlusal plane were 16.1° (±2.2), 5.8° (±2.4), 8.7° (±3.5), 10.3° (±1.3), 24.8° (±4.0), and 14.5° (±4.4),respectively. Conclusion: Angle between frankfort and canthomeatal line is very different with commonly known angle. Frankfort horizontal reference lines used for panoramic radiography need an exact definition and more accurate standard is needed for the taking of panoramic radiograph.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.61-62
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• 2006

The suppression of fluid force acting on a square prism near plane wall was studied by attaching fences on the comers of the prism. The height of the fence was 10% of the square width and the range of Reynolds number considered was $Re=2.0{\times}10^4$. The experimental parameters were the attaching position and numbers of fences, the space ratios $G/B(G/B=0.1{\sim}1.2)$ between prism and plane wall. The average drag coefficients were increased and the average hit coefficients were decreased and increased with the space ratios foulard plane wall. The drag of the prism was reduced average 7.6% with the space ratios by attaching the normal fence at the rear and upper comer and the horizontal normal fence at the rear and lower corner on the prism.

• Journal of the korean society of oceanography
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• 제38권1호
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• pp.11-16
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• 2003

The three dimensional structure of thermohaline circulation in a D-plane is investigated using a conceptual two layer model and a scaling argument. In this simple model, the water mass formation region is excluded. The upper layer represents the oceans above the main thermocline. The lower layer represents the deep ocean below the thermocline and is much thicker than the upper layer. In each layer, geostrophy and the linear vorticity balance are assumed. The cross interfacial velocity that compensates for the deep water mass formation balances downward heat diffusion from the top. From the above relations, we can determine the thickness of the upper layer, which is the same as thermocline depth. The results we get is basically the same as that we get for an f-plane ocean or the classical thermocline theory. Mass budget using the velocity scales from the scaling argument shows that western boundary and interior transports are much larger than the net meridional transport. Therefore in the thermohaline circulation, horizontal circulation is much stronger than the vertical circulation occuring on a meridional plane.

• 제어로봇시스템학회논문지
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• 제20권11호
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• pp.1153-1163
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• 2014

An efficient 3D SLAM (Simultaneous Localization and Map Building) method is developed for urban building environments using a tilted 2D LRF (Laser Range Finder), in which a 3D map is composed of perpendicular/horizontal planar polygons. While the mobile robot is moving, from the LRF scan distance data in each scan period, line segments on the scan plane are successively extracted. We propose an "expected line segment" concept for matching: to add each of these scan line segments to the most suitable line segment group for each perpendicular/horizontal planar polygon in the 3D map. After performing 2D localization to determine the pose of the mobile robot, we construct updated perpendicular/horizontal infinite planes and then determine their boundaries to obtain the perpendicular/horizontal planar polygons which constitute our 3D map. Finally, the proposed SLAM algorithm is validated via extensive simulations and experiments.

• 한국전자파학회논문지
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• 제25권5호
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• pp.559-575
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• 2014

본 논문에서는 4-포트 수평/수직 프로브 스테이션을 사용하여 수직 커넥터 핀의 특성 측정 시 사용되는 회로망 분석기의 교정용 키트(calibration kit)를 제안한다. 기존의 수평면에서 사용되는 교정키트를 사용하면, 교정 후 프로브 암의 변경 및 추가적인 장치가 필요하며, 이로 인한 시간 소요뿐 아니라, 주변 상황에 민감한 프로브 팁의 위치 변동에 기인한 정밀도 훼손의 위험이 있다. 본 논문에서는 이를 보완할 수 있는 4-포트 수평/수직 겸용 교정키트를 제시한다. 교정은 SOLT 방법을 이용하였으며, Short, Open, Load는 수평면에서 교정하며, Thru는 프로브의 위치에 따라서 교정기판의 같은 수평면에서 교정하거나 또는 교정기판의 위쪽, 아래쪽을 수직으로 연결하여 사용할 수 있도록 설계/제작하였다. 즉, 기판에 수직한 Thru를 교정할 때에는 교정키트를 수직으로 세워 키트 양면을 사용하여 교정할 수 있는 방법을 제안하였다. 제안한 교정키트에서의 SOLT 회로 반사/전달 특성을 기존 교정키트의 SOLT 회로의 반사/전달 특성과 비교 분석하였으며, 두 교정키트의 전달 특성은 길이 보정 후, 300 kHz부터 8.5 GHz까지 약 ${\pm}0.1$ dB의 차이가 있음을 확인할 수 있었다. 이와 같이 설계/제작된 4-포트 수평/수직 교정키트의 유용성을 입증하기 위하여 각각 수평 측정의 경우와 수직 측정의 경우의 두 가지 경우 사례 연구를 수행하였으며, 그 결과를 기존의 교정키트를 사용한 후 측정된 결과 데이터와 비교분석하였다.

• 지구물리와물리탐사
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• 제25권4호
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• pp.214-216
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• 2022

분포형 음향 센싱(distributed acoustic sensing, DAS)은 광섬유 케이블을 수신기로 활용하는 탐사기술로서, 석유탐사 및 지진분야에서 모니터링 목적으로 활발히 적용되고 있다. 최근에는 지하매질의 물성정보를 도출하기 위해 분포형 음향 센싱 자료를 활용한 전파형역산 연구가 수행되고 있다. 분포형 음향 센싱은 광섬유 케이블 상의 두 점 간의 위상 차이에 의한 변형률을 측정하기 때문에, 기존 전파형역산 알고리즘에 직접 활용하기 어렵다. 분포형 음향 센싱 자료를 전파형역산에 활용하기 위해, 본 연구에서는 평면파 가정에서의 변형률과 수평입자속도의 관계식을 이용한 평면파 전파형역산 알고리즘을 개발하였다. 수치실험을 통해 평면파 가정에서의 변형률과 입자속도 간의 관계식이 성립함을 확인하였다. 다양한 탐사환경에서 분포형 음향 센싱 자료에 대한 전파형역산의 적용 가능성을 확인하기 위해, 육상 및 해저면 탄성파 탐사 환경을 모사한 4층 및 수정된 Marmousi-2 속도모델을 이용하였다. 제안된 전파형역산을 통해 육상 및 해저면 탄성파 탐사 환경하에서 P파 및 S파 속도구조를 정확히 도출할 수 있었다.

• 한국가정과학회지
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• 제9권1호
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• pp.51-61
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• 2006

The purpose of this study is to examine the relation between the trend of art and fashion which predominate a certain time. In order to achieve this goal, this study intends to analyze how plasticity found in Mondrian's pictures are applied to modern fashion with its focus on formative elements. Mondrian was ahead of abstractionism, a major trend of contemporary art, and defined the theory of neo-plasticism. The theory of neo-plasticism defined by Mondrian is characterized by the limited expression of lines and shapes by using only vertical and horizontal straight lines, and right angles and four-sided figures weaved by the lines, and the use of achromatic color(black, white, and gray) in three primary colors(red, blue, and yellow). Based on his theory, he fully displayed the world of geometric abstraction. Mondrian's formative elements which have been applied in modern fashion can be divided into shape and color, For the element of shape, first, horizontal and vertical lines have been applied to patterns, trimmings, detail, and plane of textiles through simplification of design, representing proportion, balance, and stress in a silhouette, Second, plane and diamond shapes made of horizontal and vertical lines have been applied to textiles or patterns with uniqueness. For the element of color, first, three primary colors and achromatic colors are used to seek the aesthetics of balance and harmony that are produced in the strain of conflict through brightness, chroma, and complementary colors, Second, primary colors of high chroma and brightness which are much stronger than pictures are used to express a modern sense. Formative elements of neo-plasticism, which have been applied to modern fashion suggested by this study, are connected with the trend of art contemporary designers have borrowed, Accordingly, this study will become a very helpful material which provides designers with original ideas in developing materials and patterns which connect design with art.

• Geomechanics and Engineering
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• 제6권2호
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• pp.153-172
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• 2014

In order to investigate the effect of different perforation angles (the angle between the perforation direction and the maximum horizontal principal stress) on the fracture initiation and propagation during hydraulic fracturing of highly deviated well in oil & gas saturated formation, laboratory experiments of the hydraulic fracturing had been carried out on the basis of non-dimensional similar criteria by using 400^3 $mm^3$ cement cubes. A plane fracture can be produced when the perforations are placed in the direction of the maximum horizontal principal stress. When the perforation angle is $45^{\circ}$, the fractures firstly initiate from the perforations at the upper side of the wellbore, and then turn to the maximum horizontal principal stress direction. When the well deviation angle and perforation angle are both between $45^{\circ}$ and $90^{\circ}$, the fractures hardly initiate from the perforations at the lower side of the wellbore. Well azimuth (the angle between the wellbore axis and the maximum horizontal principal stress) has a little influence on the fracture geometries; however it mainly increases the fracture roughness, fracture continuity and the number of secondary fractures, and also increases the fracture initiation and propagation pressure. Oriented perforating technology should be applied in highly deviated well to obtain a single plane fracture. If the well deviation angle is smaller, the fractures may link up.

• 한국산업정보학회논문지
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• 제21권5호
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• pp.11-17
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• 2016

본 논문에서는 평면을 모델링하여 깊이 정보를 보정하고 부호화를 개선하는 방법을 제안한다. 먼저 보정하고자 하는 화소를 중심으로 수평, 수직 방향으로 최소 자승법을 이용하여 평면을 모델링한 후 예측 오차에 근거하여 예측된 평면이 적합한지 판단한다. 그 후 모델링된 평면상의 깊이 화소 값으로 보정한다. 제안된 방법을 통해 평면으로 이루어진 깊이 영상뿐만 아니라 다양한 깊이 정보를 가지는 깊이 영상에 대해서도 보정이 가능하다. 제안된 방법을 적용하여 부호화 성능을 나타내는 엔트로피 척도를 측정한 결과, 부호화 성능이 최대 80.2% 개선된 것을 확인하였다.

• 대한치과보철학회지
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• 제26권1호
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• pp.133-151
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• 1988

The objectives of this study were to compare the position of centric relation guided by means of leaf gauges, bilateral manipulation, chin-point guidance with Lucia jig and self-guided method and the reproducibility, respectively. A Veri-check (Denar Co., Anaheim, California) was employed for examining, and the displacement of position and reproducibility were verified. The following results were obtained. 1. On the sagittal plane, the centric relation guided by means of leaf gauges showed greater posterior displacement than that by means of bilateral manipulation and less than that by means of chin-point guidance with Lucia jig, and self-guided centric relation showed least posterior displacement. The centric relation guided by means of bilateral manipulation showed greater superior displacement than that by means of chin-point guidance with Lucia jig and less than that by means of leaf gauges and self-guided centric relation showed least superior displacement. 2. On the horizontal plane, the centric relation guided by means of chin-point guidance with Lucia jig showed greater posterior displacement than that of bilateral manipulation and less than that leaf gauges, however the self-guided centric relation showed slightly anterior displacement. 3. The anteroposterior displacement measured on sagittal plane and horizontal plane were highly correlated. (p<0.05). 4. The reproducibility of centric relation guided by means of leaf gauges, bilateral manipulation and chin-point guidance with Lucia jig were similar and more reproducible than self-guided centric relation.