• Title/Summary/Keyword: Polyhedra

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THE LEAST NUMBER OF COINCIDENCES WITH A COVERING MAP OF A POLYHEDRON

  • Jezierski, Jerzy
    • Journal of the Korean Mathematical Society
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    • v.36 no.5
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    • pp.911-921
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    • 1999
  • We define the coincidence index of pairs of maps p, f : $\widetilde{X}$ $\rightarrow$ X where p is a covering of a polyhedron X. We use a polyhedral transversality Theorem due to T. Plavchak. When p=identity we get the classical fixed point index of self map of polyhedra without using homology.

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Morphogenesis of Component Unit in Spatial Grid Structure (공간그리드구조 구성유닛의 형태구성)

  • Park, Chan-Soo;Choi, Sun-Young
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.3 s.25
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    • pp.125-132
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    • 2007
  • The purpose of this study is to investigate the functions and formations of the component units as aesthetic components in the spatial grid. The main subject covered here is the presentation of the morphological method of shaping spatial grid by application of 3-dimensional units satisfying the suitable form of polyhedra, tensegrity and hybrid structure. In accordance with the subject, the definition of the spatial grid and 3-dimensional nit, the relationship between them, and then the functions of those units are reviewed. And the formations of polyhedral units, tensegrity units and hybrid units are generated by means of the modules of the simplest type or pattern. And also the overall appearance of the spatial grid shaped by several basic methods in which one unit can be joined to another and arranged are depicted.

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Development of an efficient algorithm for the minimum distance calculation between general polyhedra (일반적인 다면체 사이의 최소거리 계산을 위한 효율적인 알고리즘의 계산)

  • 임준근;오재윤;김기호;김승호
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1876-1879
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    • 1997
  • This paper developes an efficient algorithm for the minimum distance calculation between general polyhedra(convex and/or concave). The polyhedron approximates and object using flat polygons which composed of more than three veritices. The algorithm developed in this paper basically computes minimun distance betwen two convex polygons and finds a set of polygons whcih makes a global minimum distance. The advantage of the algorithm is that the global minimum distance can be computed in any cases. But the big disadvantage is that minimum distance computing time is repidly increased with the number of polygons which used to approximate an object. This paper developes a method to eliminate unnecessary sets of polygons, and an efficinet algorithm to compute a minimum distance between two polygons in order to compensate the inherent disadvantage of the algorithm. It takes only a few times iteration to find minimum distance for msot polygons. The correctness of the algortihm are visually tested with a line which connects two points making a global minimum distance of simple convex object(box) and concave object(pipe). The algorithm can find minimum distance between two convex objects made of about 200 polygons respectively less than a second computing time.

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Characterization of Mamestra brassicae Nucleopolyhedrovirus (MabrNPV)-K1 Isolated in Korea

  • Lee, Jae-Kyung;Shin, Tae-Young;Bae, Sung-Min;Choi, Jae-Bang;Oh, Jeong-Mi;Koo, Hyun-Na;Kim, Ju-Il;Kwon, Min;Woo, Soo-Dong
    • International Journal of Industrial Entomology and Biomaterials
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    • v.17 no.1
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    • pp.125-129
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    • 2008
  • The purpose of this study was to investigate the characteristics of Mamestra brassicae nucleopolyhedrovirus (MabrNPV)-K1 isolated in Korea. Polyhedra of MabrNPV-K1 showed irregular appearance in shape with the average diameter $1.8{\mu}m$. MabrNPV-K1 contained a number of nucleocapsids within a viral envelope embedded in polyhedron. The polyhedrin of MabrNPV-K1 was composed of single polypeptide with a M.W. of approximate 31 kDa which is identical to the commercialized MabrNPV, Mamestrin, as a biological control agent. The nucleotide and amino acid sequences within the coding region of MabrNPV-K1 polyhedrin shared 99.0% similarity with the polyhedrin gene from previous reported MabrNPVs. The median lethal concentrations ($LC_{50}$) of MabrNPV-K1 and Mamestrin to M. brassicae larvae were $3.9{\times}10^3$ PIBs/larva and $6.0{\times}10^4$ PIBs/larva, respectively. Mortality of the MabrNPV-K1 against to the third instars larvae was 15 times higher than that of the Mamestrin. The median lethal times ($LT_{50})$ of MabrNPV-K1 by the concentration of polyhedra were lower ($4.4{\sim}6.1$ days) than those of Mamestrin ($4.1{\sim}8.6$ days). These results suggest that a local strain MabrNPV-K1 has high pathogenicity to M. brassicae and may be useful for the development of biological control agent to control this.

Microbial Control of the Tobacco Cutworm, Spodopera litura (Fab.), Using S. litura Nuclea Polyhedrosis Virus. II. Formulation of S. litura Nuclear Polyhdrosis Virus as Viral Insecticides (곤충 핵다각체병바이러스를 이용한 담배거세미나방의 생물적 방제. II. 담배거세미나방 핵다각체병바이러스의 살충제 제제화)

  • 임대준;진병래;최귀문;강석권
    • Korean journal of applied entomology
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    • v.29 no.4
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    • pp.244-251
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    • 1990
  • Three viral insecticides were differently formulated with a nuclear polyhedrosis virus isolated from Spdodoptera litura by addition of feeding attractant, anti-precipitate of polyhedra, spreading agent, and UV-protectants. Sucrose was effective for attraction of larval feeding to increase the mortality and for protection of polyhedra from inactivation by sunlight when added 1% to 5% of sucrose solution to the formulations. Contents of additives to the formulations were 0.5% in polyvinyl alcohol to prohibit the precipitation of polyhedra and 0.1% in Triton X-100 to spread and wet the formulations to the plant. Inactivation of the virus under sunlight was decreased when added 800g of white carbon to 100 L of water in the white carbon formulation and 30% of molasses to the molasses's. In the formulation of white carbon and molasses mixtures, activation of the virus was increased when mixtured 500g of the former with 10% of the latter. Three formulations were persisted their pathogenicity more than 95% of mortality at 3 days p.i. Encapsulation of the polyhedral surface was more distinctively coated with the carbon and showed more effective in the residual effects of the white carbon than others, but the molasses more attractive for larval feeding.

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studies on the induction of nuclear and cytoplasmic polyhedrosis viruses by high and low temperature treatment in the silkworm, Bombsx mori L. (고온 및 저온처리에 었어서 가잠 Virus 다각체병의 유발에 대하여)

  • 강석권
    • Journal of Sericultural and Entomological Science
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    • no.11
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    • pp.63-68
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    • 1970
  • The induction of polyhedroses in the silkworm, Bambyx mari L., was investigated treating the 5th instar larvae just after eodysis with high temperature (hot water bath at 40$^{\circ}C$ for 5 minutes or dry heat shock at 40$^{\circ}C$ for 30 minutes) and low temperature (5$^{\circ}C$ for 24 hours). The results obtained were as follows; 1. Comparing between the frequency of nuclear and cytoplasmic polyhedroses induced by cold and heat treatments (hot water bath at 40$^{\circ}C$ for 5 minutes), the induction ratio of the former is clearly less than that of the latter. But if the larvae tested with cold were left at room temperature (25$^{\circ}C$) for 30-120 minutes till the next hot water bath (40$^{\circ}C$) for 5 minutes and water bath (20$^{\circ}C$) for 5 minutes, treatments, the frequency of induced cytoplasmic polyhedrosis was more than that in the case of cold or hot water bath treatment alone. 2. The frequency of nuclear and cytoplasmic polyhedrosis induced by cold and successive heat (dry heat shock at 40$^{\circ}C$ for 30 minutes), left at room temperature (25$^{\circ}C$) ti11 the second treatment, the frequency of nuclear polyhedrosis was less than that of cytoplasmic polyhedrosis. 3. The reaction of nuclear polyhedra to stains also differs sharply from that of the cytoplasmic type. In a smear of nuclear polyhedra on a slide staining with Giemsa solution remains unstained against a stained back ground, in contrast to this, the cytoplasmic polyhedra take up stain readly.

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COXETER GROUPS AND BRANCHED COVERINGS OF LENS SPACES

  • Mednykh, Alexander;Vesnin, Andrei
    • Journal of the Korean Mathematical Society
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    • v.38 no.6
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    • pp.1167-1177
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    • 2001
  • The groups generated by reflections in faces of Coxeter polyhedra in three-dimensional Thurstons spaces are considered. We develop a method for finding of finite index subgroups of Coxeter groups which uniformize three-dimensional manifolds obtained as two-fold branched coverings of manifolds of Heegaard genus one, that are lens spaces L(p, q) and the space S$^2$$\times$S$^1$.

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