• 인지과학
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• 제17권4호
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• pp.287-301
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• 2006

깊이정보가 이차원 자극의 형태 판단에 미치는 효과를 알아보기 위하여 Posner 등(1969)의 물리적 대응과제를 이용한 두 실험을 실시하였다. 두 실험 모두 연속적으로 제시되는 두 문자나 도형이 물리적으로 동일한 형태인지 여부를 신속 정확하게 판단하는데 있어서 배경의 깊이정보가 미치는 영향에 초점을 맞추었다. 실험 1에서는 인공적으로 구성한 선형조망 단서와 결기울기 단서를, 실험 2에서는 실제 장면인 도로를 이용한 단서들을 사용하였다. 두 실험의 결과는 모두 깊이단서가 제공하는 깊이정보가 이차원 자극의 형태지각에 영향을 미치는 것으로 나타났다. 즉, 물리적으로는 형태가 동일하더라도 두 번째 대상이 깊이단서에 의해 다른 형태로 지각될 가능성이 있는 경우에는 "같다"는 물리적 대응반응의 정확도가 낮아지고 반응시간이 증가하며, 물리적으로는 형태가 다르더라도 깊이단서에 의해 동일한 형태로 지각될 가능성이 있는 경우에는 '다르다'는 정확반응이 낮아지고 반응시간이 증가하는 것으로 나타났다. 이 결과를 모양 항등성에 대한 선행연구들의 개념적 방법론적 문제점 그리고 향후 수행해야 할 연구방향의 측면에서 논의하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 추계학술대회논문집
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• pp.26-29
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• 1999

Process design for elliptically shaped deep drawing products is various according to size shape and specification of products. This study presents two approaches to design the preform that is a key process for elliptically shaped products, One of these is that cross-section of punch is circular. Another is that for the improvement of characteristics for final products the cross-section of the punch is similar to rectangular shape. After forming the preform process design of top-part drawing is the same. In the study blank shape and dimension are obtained by applying a numerical formula and surface area constancy.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1211-1221
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• 2002

A shape optimization of stiffener was conducted to increase buckling load or failure load with stiffened laminated composite panel of I-type under compression loading. Design variables are cap length, web length, and/or thickness under the constraint of volume constancy. The objective function is buckling load and failure load of post-buckling based on Tsai-Hill theory using ABAQUS 5.8 for analysis and Optimizer on Broydon-Fletcher Goldfarb-Sharno Method and Augmented Lagrange Multiplier Method. The effects of relative length of a web and a cap of stiffener on buckling load and failure load of post-buckling were investigated with the results of optimum design.

• 소성∙가공
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• 제11권5호
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• pp.405-413
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• 2002

A process planning system for cold forging of non-axisymmetric parts of comparatively simple shape was developed in this study. Programs for the system have been written with Visual LISP in AutoCAD. Shape of the product must be drawn with the solid line and the hidden line, and with the plane and front view, as well. At the plane, the system recognizes the external shape of non-axisymmetric portions - the number of the sides of the regular polygons and the radii of circles inscribing and circumscribing the polygon. At the front view, the system cognizes the diameter of axisymmetric portions and the height of the primitive geometries such as polygon, cylinder, cone, concave, convex, etc. The system perceives that the list developed from the solid line must be formed by the operation of forward extrusion or upsetting, and that the list developed from the hidden line must be formed by the operation of backward extrusion. The system designs the intermediate geometries again by considering clearance between workpiece and die, and then finally the billet diameter, in reverse order from the finished product, on the basis of volume constancy and using the operations, the forming sequence, the number of operations and the intermediate geometries which were already designed. The design rules and knowledges for the system were extracted from the plasticity theories, handbook, relevant reference and empirical knowledge of field experts. Suitability of the process planning was analyzed using SuperForge of FVM simulation package. The results of analysis showed good formability.

• 인지과학
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• 제10권3호
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• pp.17-28
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• 1999

양안 부등 정보에 근거하여 모사 된 타원형 및 포물선형 반원주체가 관찰거리가 변화함에 딸 체계적으로 왜곡되어 지각되었다. 실험1과 실험3의 두 가지 관찰조건 모두에서, 타원형 반원주체는 45 cm의 관찰거리에서는 실제 모양과 근사하게 지각되었으나 135 cm의 관찰거리에서는 실제 곡면성의 75%로 과소 평가되어 지각되었다. 실험2에서는, 관찰거리에 대한 정보가 풍부할 때, 포물선형 반원주체가 45 cm의 관찰거리에서 실제 곡면성에 비해 118%의 곡면 성을 갖는 것으로 과장되어 지각되었으며, 90 cm의 관찰거리에서는 실제에 근접하여 지각되었고, 135 cm의 관찰거리에서는 실제 곡면성에 비해 85%로 과소 평가되어 지각되었다. 관찰거리에 대한 정보가 감소된 관찰조건에서는 모든 관찰거리에서 실제의 곡면 성 보다 다소 과소 평가되어 지각되었다. 예를 들어, 45 cm의 관찰거리에서는 실제 곡면성에 근접하여 지각되었고, 135 cm의 관찰거리에서는 실제 곡면성에 비해 68%로 과소 평가되어 지각되었다. 이러한 실험 결과들은 시각기제가 양안 부등을 추정한 관찰거리로 척도와(scale) 하여 3차원 모양을 표상 하게 된다는 설명을 지지하고, 이에 대립되는 가정, 즉 거리에 따라 변하지 않는 부등 곡률(disparity curvature)을 탐지해 냄으로써 3차원 모양을 직접 지각할 수 있다는 가정이 타당하지 않음을 시사한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.420-425
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• 2004

Lee and Kang measured side-necking deformation near a crack-tip for CT specimen using Stereoscopic Digital Speckle Photography and Digital Image Correlation. In this work the same technique was applied to SENB specimen. We happened to find that the deformation shape of the side-necking is similar to the one of plastic region estimated by McClictock using slip line theory. Based on volume constancy of plastic deformation as well as this finding, it is expected that a linear relationship holds between the volume of plastic deformation region and the one of side-necking upon the lateral surface of a specimen. To prove the idea, a preliminary study has been performed using 3-D finite element method on a model with modified boundary layer formulation. As the result, it is shown that the idea works well with acceptable error.

• Advanced Composite Materials
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• 제17권1호
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• pp.1-23
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• 2008

Robotized filament winding technology involves a robot that winds a roving impregnated by resin on a die along the directions of stresses to which the work-piece is submitted in applications. The robot moves a deposition head along a winding trajectory in order to deposit roving. The trajectory planning is a very critical aspect of robotized filament winding technology, since it is responsible for both the tension constancy and the winding time. The present work shows two original rules to plan the winding trajectory of structural parts, whose shape is obtained by sweeping a full section around a 3D curve that must be closed and not crossing in order to assure a continuous winding. The first rule plans the winding trajectory by approximating the part 3D shape with straight lines; it is called the discretized rule. The second rule defines the winding trajectory simply by offsetting a 3D curve that reproduces the part 3D shape, of a defined distance; it is called the offset rule. The two rules have been compared in terms of roving tension and winding time. The present work shows how the offset rule enables achievement of both the required aims: to manufacture parts of high structural performances by keeping the tension on the roving near to the nominal value and to markedly decrease the winding time. This is the first step towards the optimization of the robotized filament winding technology.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.774-777
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• 2001

This paper describes a research work of developing a computer-aided design system of cold forging products. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plastic theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoCAD with a personal computer and is composed of six modules, which are selection of billet material, input of final product, process planning design, preform modification, insert design, shrink rings design module. Based on knowledge-based rules, the system is designed by considering several factors such as volume constancy, limite of formability by material, preform shape and so on.

• Journal of Biosystems Engineering
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• 제32권4호
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• pp.256-262
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• 2007

Image processing systems have been used to measure the plant parameters such as size, shape and structure of plants. There are yet some limited applications for evaluating plant colors due to illumination conditions. This study was focused to present adaptive methods to analyze plant leaf color regardless of illumination conditions. Color patches attached on the calibration bars were selected to represent leaf colors of lettuces and to test a possibility of health monitoring of lettuces. Repeatability of assigning leaf colors to color patches was investigated by two-tailed t-test for paired comparison. It resulted that there were no differences of assignment histogram between two images of one lettuce that were acquired at different light conditions. It supported that use of the calibration bars proposed for leaf color analysis provided color constancy, which was one of the most important issues in a video color analysis. A health discrimination equation was developed to classify lettuces into one of two classes, SOUND group and POOR group, using the machine vision. The classification accuracy of the developed health discrimination equation was 80.8%, compared to farmers' decision. This study could provide a feasible method to develop a standard color chart for evaluating leaf colors of plants and plant health monitoring system using the machine vision.

• 대한한의학원전학회지
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• 제3권
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• pp.280-398
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• 1989

The most distintive features on the Thinking Structure of the Views of the Nature and the Theories of the Medicine of the ancient Chinese are a Comprehensions to the System of the Nature which reveals in the Natural Phenomena. Nothing doesn't changed in the Nature and man also. These Changes are inevitable to the man. So it isn't easy to grasp the Essence of the Natural Phenomena which always be changed. I-Ching (易經, Book of Changes), Chung-Yung (中庸) and many other books are that has a theories about the Changes, the ancients could recognized the unchangeable constancy from the ever changeable Natural Phenomena. The unchangeable constancy on the Oriental thinking means as same as an 'Idea' on the Western thinking. These process made them shape up the Views of the Nature and the Medical theories. And Chi (氣), Yin-Yang (陰陽) and Wu-Hsing (五行) are the most important concepts of their views and theories. In the concepts of Chi as an epistemological meaning; the Nature and the Han can be appreciated as a one System, because his being is within the Changes of the Nature and should be in accord with those Changes. He was going to believe that all beings are exist as an existential rules of himself. So Chi can be thougt as an epistemological system to all beings' existence. Thinking of Yin-Yang as a existential meaning; all beings are exist having a contrary and a complementary to each other. Birth and Death, Be ginning and Finishing in a series of the process occurs in all beings are the two sides of their existential and intrinsic tendencies. That can be condensed to the Yin-Yang concepts. In the consideration of Wu-Hsing;all beings are observed and explained more deliberatively by it's own rules. By the way the concepts of Chi, Yin-Yang and Wu-Hsing which derived from the processes of the recognition to the Changes of the Nature are practiced actually by the thoughts of Harmony. And it is represented by the accordance to the Time of the Natural Changes, that is, Shiling (時令). It means a adjustments to the Time and Changes of the Nature. The health of all beings that is an aim of the Medicine can be maintained by their practical thoughts or the concepts of Shiling.