• Title/Summary/Keyword: Geometrical Shape

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The Hydraulic Geometrical Characteristics in Rivers - About river meandering - (하천 수계의 수리기하학적 특성에 관한 연구 - 하천 사행을 중심으로 -)

  • 송재우
    • Water for future
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    • v.13 no.2
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    • pp.49-54
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    • 1980
  • Meandering has been attributed to the earth's rotation, to the excessive slope and energy of a river, to changes in stage, etc. The purpose of this study is a geometrical approach of meander shape and to derive the relationship among meander characteristics. In the analysis of sime field examples, in spite of variety of meander shapes, the sine-generated curve was fit actual quite well and better than alternatives against the channel distance. An attempt is made to find considerable relation among meander characteristics. But width and meanderbelt did not show any defined trend considerable scatter of points was observed.

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Geometrical Uniformity For Space-Time Codes (시공간 부호의 기하학적 균일성)

  • 정영석;이재홍
    • Proceedings of the IEEK Conference
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    • 2003.07a
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    • pp.89-92
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    • 2003
  • A geometrically uniform code in AWGN channel has strong symmetry properties such as a) the distance profiles form codewords On C to all other codewords are all the same, and b) all Voronoi regions of codewords in C have the same shape. Such properties make the word error probability of geometrically uniform codes be transparent to the transmitted codeword. In this paper, we extend the geometrically uniform codes in AWGN channel to the geometrical uniform codes in fading channel with multiple transmit antennas.

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A Dominant Feature based Nomalization and Relational Description of Shape Signature for Scale/Rotational Robustness (2차원 형상 변화에 강건한 지배적 특징 기반 형상 시그너쳐의 정규화 및 관계 특징 기술)

  • Song, Ho-Geun;Koo, Ha-Sung
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.11
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    • pp.103-111
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    • 2011
  • In this paper, we propose a Geometrical Centroid Contour Distance(GCCD) which is described by shape signature based on contour sequence. The proposed method uses geomertrical relation features instead of the absolute angle based features after it was normalized and aligned with dominant feature of the shape. Experimental result with MPEG-7 CE-Shape-1 Data Set reveals that our method has low time/spatial complexity and scale/rotation robustness than the other methods, showing that the precision of our method is more accurate than the conventional desctiptors. However, performance of the GCCD is limited with concave and complex shaped objects.

The Peculiarities of New Textile Hand Evaluation Method

  • Eugenija, Strazdiene;Matas, Gutauskas
    • Fibers and Polymers
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    • v.7 no.4
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    • pp.414-419
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    • 2006
  • The paper presents information concerning metrological and technical characteristics of KTU-Griff-Tester device, the optimization of its parameters and the cases of its application. It was defined that the behaviour of textile material during its extraction through a rounded hole depends upon its structure. Variations of geometrical shape of woven and knitted specimens can be described by mathematical expressions of shortened epicycloids and Cassini ovals. It is shown that waving process of disc shaped specimen can be predicted on the basis of the law of sine curve. The examples of textiles treatment with different types of commercial softeners are presented, herewith showing the suitability (sensitiveness) of the new device to detect the changes of textile hand. Meantime it is shown that the level of materials anisotropy can be decided on the basis of transformations of specimen's geometrical shape.

A Note on the Hull Form Variational Methods (선형변환 방법에 대한 소고)

  • 이춘주;윤현세;유재문
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.1
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    • pp.63-68
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    • 2003
  • Systematic geometrical variation method of hull forms, such as "1 -Cp", "Swinging" and "Lackenby" are widely used in the early stage of a new design from those of a similar parent ship, which shows a better performance through the model test and/or sea trials. This method is simple and easy to modify original hull forms without changing the main characteristics. The shape of the prismatic curie can be easily varied by these methods, however, the frame line shape in the body plan can′t be generated easily, when the section shapes are complicated or have discontinuities or the mismatch of the body plan and the stem and stern profiles. To overcome this drawback of the hull form variations, a simple and useful method has been proposed in the present study.

A Study on Feed Rate Optimization in the Ball End-milling Process Regarding of Tool Path and Workpiece Shape (볼 엔드밀을 이용한 금형가공에 있어서 이송 속도 최적화에 대한 연구)

  • 김성윤
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.102-106
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    • 1996
  • In the ball end-milling process of a 3-dimensional mold, it is important to select cutting conditions and tool path considering the geometrical shape of a workpiece to reduce machining time. In this study, experiments were performed to decide allowable feed rate not breaking stability of system for different geometrical shapes. It was found that downcut is more stable than upcutting in machining side wall and downward is preferable to upward in inclined part depending on the angle of the inclination and depth of cut.

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Effects of the geometrical parameters of the core on the mechanical behavior of sandwich honeycomb panel

  • Ahmed, Settet T.;Aguib, Salah;Toufik, Djedid;Noureddine, Chikh;Ahmed, Chellil
    • Coupled systems mechanics
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    • v.8 no.6
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    • pp.473-488
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    • 2019
  • The present work is the study of mechanical behavior due to variation of the geometrical parameters in the core of the sandwich honeycomb panel. This study has allowed us to increase or decrease the strains and stresses of the panel, in changing the angle of alveolus, as explained and described below. In taking into consideration the results obtained previously to improve the mechanical properties and increase the adhesion of different parts of the panel, without changing the adhesive, we have conceived two new models, in increasing the contact surfaces in boundary of each part of the panel and giving a conical hexagonal shape in his corp.

A study on Spray Characteristic of Fuel Injection Nozzle with Geometrical Shape Changes of Needle Valve (연료분사노즐의 니들밸브 형상변화에 따른 분무특성에 관한 연구)

  • 채재우
    • Journal of the korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.35-40
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    • 1987
  • The experimental study, using constant pressure injection system, is carried out to investigate the effect of the geometrical shape changes of the needle valve of the effective flow area, the spray angle and the Sauter's Mean Diameter according to needle valve lift for a pintle-type injection nozzle. The results are as follows: 1) With the increase of the needle valve lift, the effective flow area is increased, the spray angle is at first increased and later decreased, and the Sauter's Mean Diameter is decreased. 2) It is also shown that the spray angle is maximum at the rapidly increased region of the effective flow area.

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Effect of Geometrical Shape and Cold Work on Deformation of the Hydrogen Absorption Metal with Hydrogen Absorption-Desorption Cycling (수소저장-방출싸이클링에 의한 수소저장금속의 변형거동에 관한 형상 및 가공의 영향)

  • Jeong, Y.G.
    • Transactions of the Korean hydrogen and new energy society
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    • v.14 no.3
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    • pp.207-216
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    • 2003
  • By using the electrochemical method, the relation between the deformation and the geometrical shape, and the effect of cold work on hydrogen absorption-desorption cycling in palladium were investigated, In order to study this problem, four kinds of the Pd specimens used were plates and bars as cold worked and annealed states. As results, it is found that the deformation of thickness direction in the palladium plates increased whereas other lateral directions decreased. But the palladium bars showed the same deformation ratio in all directions because of uniform distribution of the $\beta$ phase. Grains in the plate specimens were greatly deformed after hydrogenation cycling whereas grains in the bar specimens were pulverized. Also, deterioration of the hydrogen absorption rate of the bar specimen was larger than the plate specimen. And the effect of cold work on hydrogen absorption capacity was relatively small.

An exact finite element for a beam on a two-parameter elastic foundation: a revisit

  • Gulkan, P.;Alemdar, B.N.
    • Structural Engineering and Mechanics
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    • v.7 no.3
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    • pp.259-276
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    • 1999
  • An analytical solution for the shape functions of a beam segment supported on a generalized two-parameter elastic foundation is derived. The solution is general, and is not restricted to a particular range of magnitudes of the foundation parameters. The exact shape functions can be utilized to derive exact analytic expressions for the coefficients of the element stiffness matrix, work equivalent nodal forces for arbitrary transverse loads and coefficients of the consistent mass and geometrical stiffness matrices. As illustration, each distinct coefficient of the element stiffness matrix is compared with its conventional counterpart for a beam segment supported by no foundation at all for the entire range of foundation parameters.