• 한국정밀공학회지
• /
• 제9권2호
• /
• pp.44-51
• /
• 1992

This paper is concerned with the propram of the automatic mesh generation for 2-dimensional domain which contains the curved boundaries and holes. This program treats a new vertical-line drawing method. This method starts with 4-subdivisions of problem domain and the classification of the cross points of grid lines and boundaries. The new node is generated by the vertical line to the line connecting the two intersections of a boundary and two grid lines in gereral. And the node very close to the boundary is moved to the boundary. The automatic mesh generation composed of only rectangular elements is achieved by this procedure. The boundaries are piecewise-curves composed of lines, circles, arcs, and free curves. The free curves are generated by B-Spline form. Although there were some bad elements for the complex boundary, it was possible to obtain the acceptible rectangular elements for the given boundaries.

• 대한기계학회논문집A
• /
• 제25권12호
• /
• pp.1926-1932
• /
• 2001

In this second part of the paper, the automatic mesh generation and remeshing algorithm using bubble packing method is applied to the nonlinear problem. The remeshing/refinement procedure is necessary in the large deformation process especially because the mesh distortion deteriorates the convergence and accuracy. To perform the nonliear analysis, the transfer of state variables such as displacement and strain is added to the algorithm of Part 1. The equilibrium equation based on total Lagrangian formulation and elasto-viscoplastic model is used. For the numerical experiment, the upsetting process including the contact constraint condition is analyzed by two refinement criteria. And from the result, it is addressed that the present algorithm can generate the refined meshes easily at the largely deformed area with high error.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
• /
• pp.61-70
• /
• 2000

This paper described the current status of machine tool technology and its future trends with a particular emphasis on high-speed machining. People in machine tool industry have continuously sought to serve fast-changing manufacturing industry with economical machining solutins. At presents, it appears that more productivity gain is demanded to shorten time-to-market and machining requirements become more stringent. In this regard, this paper firstly addressed a high-speed spindle as a key element for the next-generation machine tools. The sequel to it apparently went to high-speed feed axes and final discussion included the problem of how to optimize overall system including servo function. Lastly a brief look to NC technology including machine intelligence was taken.

• 전산구조공학
• /
• 제9권4호
• /
• pp.141-154
• /
• 1996

드로네이 요소생성기법은 모델링 영역의 모양에 구애받지 않으면서 요소의 크기제어, 재편성, 국지요소생성 등에 있어서 탁월한 기능을 보여주고 있다. 그러나 생성되는 요소가 선형삼각형요소임으로해서 비압축성 또는 대변위거동의 근사나 복잡한 형상의 영역의 기하학적 근사에 한계를 갖고 있다. 이를 보완하기 위해 기제시된 드로네이 요소생성 알고리즘을 바탕으로한 6절점 삼각요소 생성알고리즘을 제시하여 본 기법의 완성도를 높이고 이를 성형문제에 적용해 보였다.

• 인지과학
• /
• 제3권1호
• /
• pp.79-111
• /
• 1991

본 논문에서는 얼굴영상의 분석을 위하여 필요한 지식의 표현방법과 이를 활용하는 방법에 대하여 살펴본다.얼굴에 대한 모델지식을 계층적인 프레임 구조로 표현하는 방법과,표현된 모델지식을 이용하여 가설 생성및 검증을 수행하는 방법에 대하여 살펴본다.특히,가설생성및 검증의 각 단계에서의 문제영역에 관한 지식들을 어떠한 순서및 절차로 활용할 것인가 하는 문제에 촛점을 맞춘다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.569_570
• /
• 2009

This paper presents a methodology to find the profit maximized Nash Equilibriums of each generator(or GenCo), which considers the Ramp-rate of each generator under a competitive market environment. The ramp-rate of a generator is one of the physical or technical constraints of a generator and means the ability to increase or decrease the output instantaneously. In this paper, we found several Nash Equilibriums of the generation allocation problem through Dynamic Programming in a competitive market. Individual generators participate in a game to maximize its profit through competitions and play a game with bidding strategies of its generation quantities in a spot market.

• Journal of Advanced Marine Engineering and Technology
• /
• 제31권7호
• /
• pp.833-841
• /
• 2007

The aim of this paper is to analyze the conjugate problems of heat conduction in solid walls coupled with laminar free convection flow adjacent to a vertical flat plate under boundary layer approximation. Using the similarity transformations the governing boundary layer equations for momentum and energy are reduced to a system of partial differential equations and then solved numerically using Finite Difference Method(FDM) known as the Keller-box scheme. Computed solutions to the governing equations are obtained for a wide range of non-dimensional parameters that are present in this problem, namely the coupling parameter P. the Prandtl number Pr and the heat generation parameter Q. The variations of the local heat transfer rate as well as the interface temperature and the friction along the plate and typical velocity and temperature profiles in the boundary layer are shown graphically. Numerical solutions have been consider for the Prandtl number Pr=0.70

• International Journal of Aeronautical and Space Sciences
• /
• 제8권2호
• /
• pp.107-120
• /
• 2007

Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

• 전기학회논문지
• /
• 제56권1호
• /
• pp.188-196
• /
• 2007

In this paper we propose an efficient offset curve generation algorithm for open and closed 2D point sequence curve(PS curve) with line segments in the plane. One of the most difficult problems of offset generation is the loop intersection problem caused by the interference of offset curve segments. We propose an algorithm which removes global as well as local intersection loop without making an intermediate offset curve by forward tracing of tangential circle. Experiment in computer sewing machine shows that proposed method is very useful and simple.

• Journal of Multimedia Information System
• /
• 제5권1호
• /
• pp.21-26
• /
• 2018

Recently, data analysis technology through artificial intelligence is attracting major attention in various industrial fields. In addition, with the increase in personal income, nowadays, the importance of heterogeneous leisure life is becoming more prominent. However, there is a problem that the tourism industry is not out of the traditional service framework. For the ultimate development of the tourism industry, it is time to provide more scientific and systematic tourism services. In this paper, various data analysis techniques in the field of computer science are applied to the field of tourism to realize next generation tourism services. To this end, the scope of this study is limited to the aviation service, and a natural ecosystem of the aviation industry for future-oriented services of aviation tourism that can improve the efficiency of aviation service gradually is established. The proposed method effectively solves the problems of traditional aviation services through data analysis techniques with artificial intelligence techniques in computer science. We expect that it will enhance the customized satisfaction of customers through personalized service and foster loyal customers in aviation companies through the method proposed.