• 제목/요약/키워드: orthogonal complex structure

검색결과 33건 처리시간 0.028초

ORTHOGONAL ALMOST COMPLEX STRUCTURES ON THE RIEMANNIAN PRODUCTS OF EVEN-DIMENSIONAL ROUND SPHERES

  • Euh, Yunhee;Sekigawa, Kouei
    • 대한수학회지
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    • 제50권2호
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    • pp.231-240
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    • 2013
  • We discuss the integrability of orthogonal almost complex structures on Riemannian products of even-dimensional round spheres and give a partial answer to the question raised by E. Calabi concerning the existence of complex structures on a product manifold of a round 2-sphere and of a round 4-sphere.

SEMIALGEBRAIC G CW COMPLEX STRUCTURE OF SEMIALGEBRAIC G SPACES

  • Park, Dae-Heui;Suh, Dong-Youp
    • 대한수학회지
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    • 제35권2호
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    • pp.371-386
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    • 1998
  • Let G be a compact Lie group and M a semialgebraic G space in some orthogonal representation space of G. We prove that if G is finite then M has an equivariant semialgebraic triangulation. Moreover this triangulation is unique. When G is not finite we show that M has a semialgebraic G CW complex structure, and this structure is unique. As a consequence compact semialgebraic G space has an equivariant simple homotopy type.

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직교 직물 복합재료 물성치 예측을 위한 가상 수치 실험 (Virtual Experimental Characterization of 3D Orthogonal Woven Composite Materials)

  • 이창성;신헌;김승조
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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    • pp.205-210
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    • 2001
  • In this work, virtual material characterization of 3D orthogonal woven composites is performed to predict the elastic properties by a full scale FEA. To model the complex geometry of 3D orthogonal woven composites, an accurate unit structure is first prepared. The unit structure includes warp yarns, filler yarns, stuffer yams and resin regions and reveals the geometrical characteristics. For this virtual experiments by using finite element analysis, parallel multifrontal solver is utilized and the computed elastic properties are compared to available experimental results and the other analytical results. It is founded that a good agreement between material properties obtained from virtual characterization and experimental results. Using the method of this virtual material characterization, the effects of inconsistent filler yarn distribution on the in-plane shear modulus and filler yarn waviness on the transverse Young's modulus are investigated. Especially, the stiffness knockdown of 3D woven composite structures is simulated by virtual characterization. Considering these results, the virtual material characterization of composite materials can be used for designing the 3D complex composite structures and may supplement the actual experiments.

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실험계획법과 콤플렉스법에 의한 고성능 유압휴즈의 최적 설계 (Optimal Design of A Quick-Acting Hydraulic Fuse Using Design of Experiments and Complex Method)

  • 이성래
    • 드라이브 ㆍ 컨트롤
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    • 제12권4호
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    • pp.8-14
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    • 2015
  • A quick-acting hydraulic fuse, which is mainly composed of a poppet, a seat, and a spring, must be designed to minimize the leaked oil volume during fuse operation on a line rupture. The optimal design parameters of a quick-acting hydraulic fuse were searched using the design of experiments method and the complex method. First, the $L_{50}(5^4)$ orthogonal array is used to find the robust minimum point among the 625 points of design variables. The search range can then be narrowed around the robust minimum point. Second, the $L_{25}(5^4)$ orthogonal array is used to obtain the variations of the design variables in the narrowed search range. The variations of design variables are used to set the structure of a polynomial equation representing the leakage oil volume of the quick-acting hydraulic fuse. The least squares method is then applied to obtain the coefficients of polynomial equation. Finally, the complex method is used to find the optimal design parameters where the objective function is described by the polynomial equation.

범용 열/유체 유동해석 프로그램 NUFLEX의 개발 (A Development of General Purpose Program NUFLEX for the Analysis of Heat/Fluid Flow)

  • 허남건;원찬식;손기헌;유홍선;신동신
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2004년도 추계 학술대회논문집
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    • pp.53-59
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    • 2004
  • A general purpose program NUFLEX for the analysis of 3-D heat/fluid flow in complex geometry with pre/post processor have been developed, which consists of a flow solver based on FVM and a dedicated pre/post processor. The program employs a general non-orthogonal grid system and solve laminar and turbulent (lows with standard and RNG $\kappa-\epsilon$ turbulence models. NUFLEX is capable of analysing two-phase flow with topologically complex interface, turbulent diffusion combustion, solidification problems and magnetic flow. For the purpose of verification of the program and testing the applicability, several practical problems are solved and compared with the available data. Comparison of the NUFLEX results with that by the STAR-CD program has been also made for the same flow configuration and grid structure.

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계층적 모델에 의한 3차원 재구성 영상의 임의단면 표시 (Arbitrary Cross Sectional Display from Three-dimensional Reconstructed Image by Hierarchical Model)

  • 유선국;김선호
    • 대한의용생체공학회:의공학회지
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    • 제10권2호
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    • pp.157-164
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    • 1989
  • Three-dimensional imaging and manipulation of CT data are becoming increasingly important for deterRing the complex structure and pathologies. Octree which is a hierarchical data model is used to reconstruct three- dimensional objects from CT scans. Orthogonal cross sections are displayed by traverse the octree partially. Arbitrary oblique planes are derived by intersecting the square region of plane and cubic volume of octal node. Thia method enables the display of multi-structured complex organ ann the realization by personal computer.

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ON THE LIE DERIVATIVE OF REAL HYPERSURFACES IN ℂP2 AND ℂH2 WITH RESPECT TO THE GENERALIZED TANAKA-WEBSTER CONNECTION

  • PANAGIOTIDOU, KONSTANTINA;PEREZ, JUAN DE DIOS
    • 대한수학회보
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    • 제52권5호
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    • pp.1621-1630
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    • 2015
  • In this paper the notion of Lie derivative of a tensor field T of type (1,1) of real hypersurfaces in complex space forms with respect to the generalized Tanaka-Webster connection is introduced and is called generalized Tanaka-Webster Lie derivative. Furthermore, three dimensional real hypersurfaces in non-flat complex space forms whose generalized Tanaka-Webster Lie derivative of 1) shape operator, 2) structure Jacobi operator coincides with the covariant derivative of them with respect to any vector field X orthogonal to ${\xi}$ are studied.