• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.1-17
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• 2004

The famous Newton-Kantorovich hypothesis has been used for a long time as a sufficient condition for the convergence of Newton method to a solution of an equation in connection with the Lipschitz continuity of the Frechet-derivative of the operator involved. Using Lipschitz and center-Lipschitz conditions we show that the Newton-Kantorovich hypothesis is weakened. The error bounds obtained under our semilocal convergence result are finer and the information on the location of the solution more precise than the corresponding ones given by the dominating Newton-Kantorovich theorem, and under the same hypotheses/computational cost, since the evaluation of the Lipschitz also requires the evaluation of the center-Lipschitz constant. In the case of local convergence we obtain a larger convergence radius than before. This observation is important in computational mathematics and can be used in connection to projection methods and in the construction of optimum mesh independence refinement strategies.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1-8
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• 2005

This paper addresses the analysis of the combustion characteristics in the oil burner using swirl flow. The reduction of exhaust emissions and high efficiency combustion techniques of the industrial burner have been studied to conserve environmental resources. We make swirl burner equal to dimension of wide burner and it is turn round of the combustion gas in construction. For a vigorous inner flow possessde 3m/s velocity in combustion gas of two burners. In calculation, we make use of a densely mesh to detailed analysis. In this study, the effect of swirl flow on the combustion of a commercial burner is analysed by experimental and also simulative manner. The results show the swirl burner has 40% better efficiency and less emissions of CO, HC, NOx and Smoke.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.975-978
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• 2003

초고속 통신망의 발달과 개인 컴퓨터의 고급화가 이루어지면서 분산 환경에서 네트워크에 연결된 이런 고급화된 컴퓨터들의 유휴자원을 이용하여 대규모의 데이터를 처리하기 위한 연구와 기존의 클라이언트-서버 환경에서의 부하를 각 컴퓨터들에게 분산시키는 연구가 활발하게 진행되고 있다. 본 논문에서는 Peer-to-Peer환경에서 메시지 제어를 위한 mesh 기반의 네트워크를 구성하고 Gossip 프로토콜을 이용한 각 peer간의 효율적인 메시지 전송 기법을 제안한다.

• Computational Structural Engineering
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• v.4 no.1
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• pp.109-120
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• 1991

This paper introduces a geometric modelling system adopted in a newly developed preprocessor for finite element analysis of three dimensional structures. The formulation is characterized by hierachical construction of structural model which consists of control points, curves, surfaces and solids. Various surface and solid modelling schemes based on blending functions and boundary representation are systematized for finite element mesh generation. The modelling system is integrated with model synthesis and operations which facilitate modelling of complex structures.

• International Journal of CAD/CAM
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• v.2 no.1
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• pp.55-67
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• 2002

In many areas of industry, it is desirable to have fast and reliable systems in order to quickly obtain suitable solid models for computer- aided analyses. Nevertheless it is well known that the data exchange process between CAD modelers and CAE packages can require significative efforts. This paper presents an approach for geometrical data exchange through triangulated boundary models. The proposed framework is founded on the use of STL file specification as neutral format file. This work is principally focused on data exchange among CAD modelers and FEA packages via STL. The proposed approach involves the definition of a topological structure suitable for the STL representation and the development of algorithms for topology and geometry data processing in order to get a solid model suitable for finite element analysis or other computer aided engineering purposes. Different algorithms for model processing are considered and their pros and cons are discussed. As a case study, a prototype modeler which supports an exporting filter for a commercial CAE package has been implemented.

• Structural Engineering and Mechanics
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• v.12 no.5
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• pp.475-490
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• 2001

Remeshing strategies are formulated for r-adaptive and h/r-adaptive analysis of crack propagation. The relocation of the nodes, which typifies r-adaptivity, is a very cheap method to optimise a given discretisation since the element connectivity remains unaltered. However, the applicability is limited. To further improve the finite element mesh, a combined h/r-adaptive method is proposed in which h-adaptivity is applied whenever r-adaptivity is not capable of further improving the discretisation. Two and three-dimensional examples are presented. It is shown that the r-adaptive approach can optimise a discretisation at minimal computational costs. Further, the combined h/r-adaptive approach improves the performance of a fully r-adaptive technique while the number of h-remeshings is reduced compared to a fully h-adaptive technique.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.4
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• pp.529-540
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• 1995

The paper deals with a procedure for constructing a composite surface interpolating a polygonal curve mesh defined from 3D scattered points. The procedure consists of a poly-angulation, construction of a curve net, and interpolation of the curve net. The poly-angulation contains a stage that changes a triangular edge net obtained from a triangulation into a poly-angular edge net. A curve net is constructed by replacing edges on the edge net with cubic Bezier curves. Finally, inside of an n-sided polygon is interpolated by n subdivided triangular subpatches. The method interpolates given point data with relatively few triangular subpatches. For an n-sided polygon, our method constructs an interpolant with n subdivided triangular subpatches while the existing triangular surface modeling needs 3(n-2) subpatches. The obtained surface is composed of quartic triangular patches which are $G^1$-continuous to adjacent patches.

• Journal of Integrative Natural Science
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• v.12 no.1
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• pp.1-8
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• 2019

Smart pole is one of mega trend in smart city development. It has multi-function to get as much as data from the street to better city management. And smart street lighting of smart pole as core part of smart city development is being implemented by many cities in globally. Refer to the latest edition of Navigant Research's Smart City Tracker includes smart city projects in 221 cities, a quarter of which are deploying smart street lighting ranging from initial pilots to citywide and regional deployments that span tens and even hundreds of thousands of lights. The most important feature of smart street lighting solution is "Connectivity" through the IoT technology. In order to implement the smart city, we should have so-called intelligent watchdog and mesh networked post for keeping the various smart city technology development progress and operation properly. Smart street lighting solution could be main infrastructure as an enabler for a range of smart city applications. We can talk about the expected role of smart street lighting for the smart city development on this paper.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.292-294
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• 2020

3DoF+ 및 6DoF를 구현하기 위해선 사용자의 움직임에 따른 운동시차를 반영하여 가상 시점 이미지를 렌더링 해야 한다. 이를 위한 방법 중 하나인 멀티뷰 기반 합성 방법은 멀티뷰 데이터(텍스쳐, 뎁스맵, 카메라 파라미터)를 기반으로 가상 시점 이미지를 합성한다. 본 논문은 멀티뷰 기반 합성의 과정 중 하나인 메쉬 구성 단계에서 뎁스맵과 텍스쳐의 엣지 정보를 고려한 효율적인 메쉬 구성을 제안한다. 제안 방법은 각 2×2 화소 격자 단위로 엣지의 방향을 측정하고 측정한 엣지를 고려한 보간으로 1/2 화소들을 생성한 뒤, 이 새로운 화소들을 메쉬 구성에 이용하여 기존 방법보다 특성이 비슷한 화소끼리 메쉬를 구성하게 하였다. 제안한 방법으로 합성된 이미지는 뭉게짐 현상과 잔상 현상이 사라진 결과를 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.928-931
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• 2007

다중 전송률을 지원하는 무선 메쉬 네트워크에서 노드는 전송률 조절을 함으로써 링크의 전송범위를 동적으로 조절할 수 있다. 다중 전송률 무선 메쉬 네트워크에서의 브로드캐스트 알고리즘인 WCDS 에서는 브로드캐스트 트리 생성시 고려하는 노드가 같은 비교 값을 가졌을 때 임의로 노드를 선택한다. 본 논문에서는 이를 보완하여 소스노드로부터의 지연시간을 고려하여 전체 지연시간 최소화를 위한 브로드캐스트 알고리즘인 MinLink_WCDS 알고리즘을 제안한다. 시뮬레이션을 통해 802.11 파라미터를 기본으로 한 다중 전송률 무선 메쉬 네트워크에서 MinLink_WCDS 알고리즘과 기존에 제안된 알고리즘들과의 지연시간 결과를 비교하여 브로드캐스트 지연시간이 향상된 것을 보여준다.