요트 설계시 선형의 기하학적 특성과 성능 사이의 관련성에 관한 연구

하득기(DEUCK-GI HA),김수영(SOO-YOUNG KIM),김용재(YONG-JAE KIM) 한국해양공학회 2003 한국해양공학회지 Vol.17 No.6

Yacht design is significantly affected by the hull geometrical characteristics. Therefore, it is necessary to closely examine the relation between hull and performance, before considering characteristics of sea condition. In this study, Genetic Programming is used to derive a formula for the relationship between hull geometric characteristics and performance. Using the formula, a new guideline is proposed to determine performance of a yacht.

기하학적 도형의 형태적 특징이 크기지각에 미치는 영향

김현정(Kim, Hyeon-Jeong) 인제대학교 디자인연구소 2008 Journal of Integrated Design Research (JIDR) Vol.7 No.2

The present study was designed to investigate how size perception of plane geometrical patterns was influenced by configurational characteristics. Nine planes with different configurations (triangle, inverted triangle, square, circle, diamond, horizontal and vertical rectangles, pentagon, and hexagon) were used as test patterns. The physical area of each test pattern was the same and was depicted by line and painting. Subjects were asked to rank the test patterns in order of perceived size. It was found that the triangle and inverted triangle shapes were perceived as the largest; with the diamond third. These results imply that the periphery, interior angle, and orientation of the plane were the main determinants of size perception.

A Study on the Air-Lubricated Herringbone Groove Journal Bearing by Finite Element Method

Park, Shin Wook,Rhim, Yoon Chul Korean Tribology Society 2001 KSTLE International Journal Vol.2 No.1

The herringbone groove journal bearing (HGJB) has chevron type grooves on stationary or rotating member of the bearing so that they pump the lubricant inward the grooves when journal rotates. As a result, the pressure is generated around the journal so that the radial stiffness and dynamic stability are improved comparing to the plain journal bearing (PJB) when the bearing operates near the concentric condition. The narrow groove theory, conventionally adopted to simulate the concentric operation of HGJB, is limited to the infinite number of grooves. A numerical study of air-lubricated HGJB is presented for the finite number of grooves. The compressible isothermal Reynolds equation is solved by using Finite Element Method together with the Newton-Raphson iterative procedure and perturbation method. The solutions render the static and dynamic performances of HGJB. Comparison of present results with a PJB validates previously published finite difference solution. The HGJB's geometric parameters influence its static and dynamic characteristics. The optimum geometric parameters are presented for the air-lubricated HGJB in particular conditions.

진동제어 콘크리트 개발에 관한 실험적 연구(I)

정영수,이대형,최우성 한국콘크리트학회 1996 콘크리트학회지 Vol.8 No.5

Recently, the construction of infrastructures has been booming and accelerating to keep up with rapid economic growth. Construction activities and operation of transportation facilities cause unfavorable effects such as civil petitions associated with vibration-induced damages or nuisances. Accordingly, the objective of this study is to develop vibration-controlled concrete using various vibration-controlled mixtures, and also to recycle obsolete materials in part. As the first step to achieve this research, preliminary mix designs have been carried out to obtain an appropriate mix proportion above 200kg/$\textrm{cm}^2$ in uniaxial compressive strength. Test specimen based on the mix proportion selected have been actuated by the impact hammer to investigate their dynamic characteristics. Vibration-controlled mixtures are foam, latex, rubber powder and plastic resin, which have been determined to reduce a vibration by and large. KS F2437 and travel time method have been used to figure out 1st natural frequency and dynamic elastic moduli. Damping ratios have been computed by adopting the polynomial curvefitting method and the geometric analysis method on the frequency response spectrum curve. of which results have been compared and analyzed hereon.

○○○설계 프로젝트에서 나타나는 건축장과 프랙탈 구조의 특성에 관한 연구

이승용 한국문화공간건축학회 2018 한국문화공간건축학회논문집 Vol.- No.64

The architectural field understood the conceptual geometry of relation, but it is difficult to show the architecture as a form. To design the architectural form on the conceptual idea of the architectural field, the clue of design for form of architectural field could be found from the fractal system which is showed of the geometrical characteristic of the chaos phenomenon of nature. The fractal system has three characteristics, those are self-similarity, self-production and self-organization. The self-similarity is that the part has a similarity system as a whole, and it show the similar composition of the area of the architectural field by composing the similar network of any area among the environments, exterior and architecture. The self-production is that the making organization by combining, and it show the similar composition of the interaction of the architectural field that the architecture interact to environment and by this interaction to create new but interacted architecture continously. The self-organization is the organizing by itself on internal logic, and it show the composition of the integration of the architectural field by connecting building and space to one as a building and a space are no longer divided by flexibility, diversity and graduations. Therefore the architectural field is showed the geometrical characteristics of the fractal system.

Parametric Surface Defined on Parallelogrammic Domain and its Properties

FAN Shuqian,ZOU Jinsong,SHI Mingquan (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

As essential components of many mechanical systems, tooth geometrical properties of spiral bevel gears greatly influence on the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show unique advantage in transmission due to their constant spiral angle property. However, mathematical model suitable for accurate digital modeling, differential geometrical characteristics and related contact analysis methods of tooth surface have not been deeply investigated, since such gears are not convenient to traditional cutting manufacture in gear industry. An accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry. Actually, the tooth surface is a parametric surface defined on parallelogrammic domain. Then, an equivalence proof of the tooth surface geometry is given in order to greatly simplify the mathematical model. As major factors affecting lubrication, surface fatigue, contact stress, wear and manufacturability of gear teeth, differential geometrical characteristics of the tooth surface is summarized employing classical fundamental forms. By using mentioned geometrical properties, manufacturability and its limitation of logarithmic spiral bevel gears is analyzed using precision forging and multi-axis freeform milling, instead of classical cradle-type machine tools based milling or hobbing. Geometry and manufacturability analysis result shows that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multi-axis freeform milling should be further solved.

마들렌느 비오네의 작품에 나타난 기하학적 특성에 관한 연구

유수경,김의경 服飾文化學會 2002 복식문화연구 Vol.10 No.6

The aim of this research is to analyze Vionnet's geometric features, which can be regarded as the key formative beauty among the external characteristics of her works, and to thereby establish the theory that her works emitted a time-transcending life force because they were patterns designed based on a geometrical frame of mind. To prove such argument, atudies to understand the basic geometrical aspects appearing in her works will be made by taking a look at the general features of geometry, viewing Vionnet's philosophy for designing and examining the geometric cutting methods. The period covered in this paper will center mainly on dresses Vionnet made from her very active days in the fashion sector. 1919, till when she retired from the fashopn industry, around 1939. What's outstanding about Vionnet's geometric principle expressed in her works is the unique cutting method that acknowledges the silhouette of the human body as a cubic or three-dimensions concept, through insight of the human body, the mechanics of the materials, and geometry. Vionnet introduced a simple and elegant design by combining geometric figure cuts, such as rectangles, quadrants, and triangles Moreover, she created a new sewing structure that plans everything about the materials to the tiniest detail, resulting in producing a softer style. With this, Vionnet showed the geometrical correlation can bring about harmony and the beauty of ideal proportion forming the source of eternal beauty. As discussed so far the geometrical characteristics appearing in Vionnet;s works are marked such as spirals, zig-zag lines, asymmetries, panels, gradation. golden proportion, and the mobius-band.

Optimization of geometrically asymmetric straight trapezoidal fins

강형석 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

Geometrically asymmetric trapezoidal fins with variable slope of fin’s top surface are optimized for fixed fin volumes. Convectionfrom the inside fluid to the inside wall, conduction from the inside wall to the fin base and conduction through the fin base are consideredsimultaneously for the fin base boundary condition. For fixed fin volumes, the optimum heat loss, the corresponding optimum fin length,and fin base height are presented as functions of the fin base thickness, inside fluid convection characteristic number, fin volume, finshape factor, and ambient convection characteristic number. The optimum values between 1-D and 2-D analyses are compared. One ofthe results shows that both the optimum fin length and fin base height decrease with the increase of the fin shape factor.

지질조건에 따른 자연사면 산사태의 기하학적 특성

김경수 ( Kyeong Su Kim ),송영석 ( Young Suk Song ),채병곤 ( Byung Gon Chae ),조용찬 ( Yong Chan Cho ),이춘오 ( Choon Oh Lee ) 대한지질공학회 2007 지질공학 Vol.17 No.1

The recognitions of geometrical characteristics and occurrence conditions are very important to evaluate the landslides in natural terrains. In this paper, the geometrical characteristics of landslides are analyzed according to a geological condition in three landslides areas. The three landslides areas are classified to the geological condition. The three landslides areas are Jangheung, Sangju and Pohang. The geology of Jangheung area, Sangju area and Pohang area is gneiss, granite, and the tertiary sedimentary rock, respectively. During a heavy rainfall of 150~588 mm in these areas, 1,582 landslides have occurred in 1998. The geometrical characteristics according to the geological condition analyzed from the investigation of these landslides. The frequency of landslide is high exceedingly above 90% of a slope attitude, while the frequency is very low below 70%. The frequency of landslide is high exceedingly between 26o and 30o of slope angle, while the frequency is very low below 20o. The size of the landslides is ranged from several tens to several hundreds . The length is ranged from 5 m to 300 m, and the width is ranged from 3 m to 50 m. Also, the depth is less than 1m. Therefore, the landslides in these areas have small width, long length and shallow depth. The type of the landslides is changed from transitional slide at the scarp to debris flow at the low part of slope.

A Study on the Face Recognition based on the Face Geometrical Characteristics

Dadong Zhao,Jeong-Young Song 한국정보기술학회 2010 Proceedings of KIIT Conference Vol.2010 No.-

This paper has analyzed face characteristics and designed the face features, then it extracts the features and constructed the feature values, and at last, it realizes face recognition through matching of similarity of the feature values. According to the obvious difference of the five sense organs in color, using rgb color space to analyze the distribution range of the five sense organs, and in accordance with the statistical results, the five sense organs in the face are segmented and geometrical parameters of the relevant facial parts are obtained. Construction face feature values with the feature values formed with the proportion of these parameters. Face recognition is to match the feature values. As the extracted feature values have different stability and contribution to the recognition, this paper grants different coefficients to the components, and then uses weighted similarity calculation method to work out the similarity value. Finally, this paper set the maximum similarity matching as the basis for face recognition. For the selection of feature components, we have comprehensively considered the overall features and partial features of face and combined the face shape features and the features of the five sense organs. The experiment shows that these features can reflect the individual features of human face, which can be treated as an effective basis for face recognition, thus to realize face recognition.