• 제목/요약/키워드: Polyhedra

검색결과 107건 처리시간 0.039초

ESTIMATION OF THE NUMBER OF ROOTS ON THE COMPLEMENT

  • Yang Ki-Yeol
    • The Pure and Applied Mathematics
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    • 제13권1호
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    • pp.11-18
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    • 2006
  • Let f : (X, A) ${\rightarrow}$ (Y, B) be a map of pairs of compact polyhedra. A surplus Nielsen root number $SN(f;X\;{\backslash}\;A,\;c)$ is defined which is lower bound for the number of roots on X \ A for all maps in the homotopy class of f. It is shown that for many pairs this lower bound is the best possible one, as $SN(f;X\;{\backslash}\;A,\;c)$ can be realized without by-passing condition.

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ON CERTAIN CLASSES OF LINKS AND 3-MANIFOLDS

  • Kim, Soo-Hwan;Kim, Yang-Kok
    • Communications of the Korean Mathematical Society
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    • 제20권4호
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    • pp.803-812
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    • 2005
  • We construct an infinite family of closed 3-manifolds M(2m+ 1, n, k) which are identification spaces of certain polyhedra P(2m+ 1, n, k), for integers $m\;\ge\;1,\;n\;\ge\;3,\;and\;k\;\ge\;2$. We prove that they are (n / d)- fold cyclic coverings of the 3-sphere branched over certain links $L_{(m,d)}$, where d = gcd(n, k), by handle decomposition of orbifolds. This generalizes the results in [3] and [2] as a particular case m = 2.

THE KNOT $5_2$ AND CYCLICALLY PRESENTED GROUPS

  • Kim, Goan-Su;Kim, Yang-Kok;Vesnin, Andrei
    • Journal of the Korean Mathematical Society
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    • 제35권4호
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    • pp.961-980
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    • 1998
  • The cyclically presented groups which arise as fundamental groups of cyclic branched coverings of the knot $5_2$ are studied. The fundamental polyhedra for these groups are described. Moreover the cyclic covering manifolds are obtained in terms of Dehn surgery and as two-fold branched coverings of the 3-sphere.

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Development of a Robot Off-Line Programming System with Collision Detection

  • Lee, Sang-Cheol;Lee, Kwae-Hi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.113.2-113
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    • 2001
  • In this paper, we present a robot off-Line programming system with collision detection. The collision detection is a very important factor of robot oft-line programming system for collision avoidance, path planning, and so on. The System developed in this paper, basically using an algorithm for the minimum distance calculation between general polyhedra. The proposed system shows an exact and interactive result in static and dynamic environments.

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A Collision Avoidance Method for Two Articulated Robot Manipluators (두대의 회전 다관절형 로봇 머니퓰레이터를 위한 충돌회피 방법)

  • Chang, C.;Chung, M.J.;Lee, B.H.
    • Proceedings of the KIEE Conference
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    • 대한전기학회 1990년도 하계학술대회 논문집
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    • pp.480-484
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    • 1990
  • A simple time-delay method for avoiding collisions between two articulated robot manipulators is proposed. Links of robot are approximated by polyhedra and the danger of collision between two robots is expressed by distances between the robots. An algorithm, which can fast obtain the minimum time-delay value needed for collision avoidance, using scheme of following the boundary contour of collision region in the collision map which has information about collisions between two robots, is described.

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Medial Surface Computation of Polyhedra (다면체의 중립면 계산)

  • 이용구;이건우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.833-840
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    • 1996
  • 중립면은 셸 (솔리드 모델) 유한 요소 생성, 로보트 이동 경로 계산, 특징 형상 판별 등에서 사용될 수 있다. 그러나 기존 중립면 계산 알고리즘들은 연립 방정식을 수렴성이 보장되지 않는 수치 해법으로 풀어야 했기 때문에 발전이 미비했다. 본 논문은 복셀-이등분 면의 교자성을 이용한 중립면 계산 알고리즘을 제시한다. 교차성은 보로노이 영역을 사용, 단순한 기하학적 요소간의 거리 비교로 판별한다. 이런 기하학적인 접근 방법은 기본적으로 수렴성 문제가 배제된다.

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AN ELEMENTARY PROOF OF SFORZA-SANTALÓ RELATION FOR SPHERICAL AND HYPERBOLIC POLYHEDRA

  • Cho, Yunhi
    • Communications of the Korean Mathematical Society
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    • 제28권4호
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    • pp.799-807
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    • 2013
  • We defined and studied a naturally extended hyperbolic space (see [1] and [2]). In this study, we describe Sforza's formula [7] and Santal$\acute{o}$'s formula [6], which were rediscovered and later discussed by many mathematicians (Milnor [4], Su$\acute{a}$rez-Peir$\acute{o}$ [8], J. Murakami and Ushijima [5], and Mednykh [3]) in the spherical space in an elementary way. Thereafter, using the extended hyperbolic space, we apply the same method to prove their results in the hyperbolic space.

Function and Oligomerization Study of the Leucine Zipper-like Domain in P13 from Leucania separata Multiple Nuclear Polyhedrosis Virus

  • Du, Enqi;Yao, Lunguang;Xu, Hua;Lu, Songya;Qi, Yipeng
    • BMB Reports
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    • 제40권2호
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    • pp.232-238
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    • 2007
  • The p13 gene is uniquely present in Group II nucleopolyhedroviruses (NPVs) and some granuloviruses, but not in Group I NPVs. p13 gene was first described by our laboratory in Leucania separatamultiple nuclear polyhedrosis virus (Ls-p13) in 1995. However, the functions of Ls-P13 and of its homologues are unknown. When Ls-p13 was inserted into Autographa californica nucleopolyhedrovirus, a Group I NPV, polyhedra yield was inhibited. However, this inhibition was prevented when the leucine zipper-like domain of Ls-p13 was mutated. To determine the cause of this marked difference between Ls-P13 and leucine zipper mutated Ls-P13 (Ls-P13mL), oligomerization and secondary structure analyses were performed. High performance liquid chromatography and yeast two-hybrid assays indicated that neither Ls-P13 nor Ls-P13mL could form oligomers. Informatics and circular dichroism spectropolarimetry results further indicated marked secondary structural differences between Ls-P13 and Ls-P13mL. The LZLD of Ls-P13 has two extended heptad repeat units which form a hydrophobic surface, but it is short of a third hydrophobic heptad repeat unit for oligomerization. However, the mutated LZLD of Ls-P13mL lacks the above hydrophobic surface, and its secondary structure is markedly different. This difference in its secondary structure may explain why Ls-P13mL is unable to inhibit polyhedra yield.

Characteristics of Autographa californica Nuclear Polyhedrosis Virus in Spodoptera exigua Cell Line. (파밤나방 세포주에서 Autographa californica 핵다각체병 바이러스의 감염 특성)

  • 최재영;우수동;홍혜경;강석권
    • Microbiology and Biotechnology Letters
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    • 제26권2호
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    • pp.161-166
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    • 1998
  • To study the usefulness of Se301 cells, which is originated from Spodoptera exigua and has susceptibility to the Autographa californica NPV (AcNPV), as a host for the AcNPV-based expression vector system, we compared the characteristics of AcNPV in Se301 and Sf-21 cells. The symptom by viral infection was similar in both of cells, but the ratio of polyhedra released from the cell was higher in Se301 cells than in Sf-21 cells. The overall PIB productivity of AcNPV was similar in both cells but the size of polyhedra was larger in Se301 cells. While the polyhedrin expression efficiency was about 2.4 times higher in Se301 cells than in Sf-21 cells, the viral growth was higher in Sf-21 cells. These results suggested that Se301 cell is very useful in the AcNPV-based expression system as a host.

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