• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.9-14
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• 2000

Computational methods can be classified roughly into two parts: one is the methods based on a potential flow theory, and the other is numerical solvers(CFD) based on Navier-Stockes equation. Methods based on a potential theory are more effective than CFD when the free surface effect is considered. Especially Rankine source method seems to become widespread for simulations of wave making problems. For computations of viscous flow problems, CFD techniques have rapidly been developed and have shown many successful results in the viscous flow calculation. Present paper introduces a computational system 'WAVIS' which includes a pre-processor, potential ant viscous flow solvers and a post-processor. To validate the system, the calculated results for modem commercial hull forms are compared with measurements. It is found that the results from the system are in good agreement with the experimental data, illustrating the accuracy of the numerical methods employed for WAVIS.

• Prospectives of Industrial Chemistry
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• v.15 no.3
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• pp.39-48
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• 2012

현대 컴퓨터산업의 진보는 제일원리 전산법이 여러 연구개발 분야에 널리 사용되는 길을 열었다. 이 논문에서는 제일원리 전산법을 이용한 신 재생에너지의 고성능 나노 소재개발 및 디자인 연구사례를 통해 그 기초 원리와 다양한 응용분야 및 실험과의 효율적인 연계성 등을 소개하고자 한다.

• Computational Structural Engineering
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• v.1 no.1
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• pp.87-94
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• 1988

The linerization method as one of the recursive quadratic programming method is applied for the optimal design of a large-scale structure supported by Pshenichny's proof of global convergence of the algorithm and convergence rate estimates. The linearization method transforms all constants of the design problem into an equivalent linearized constraint and employs the active-set strategy. This results in substantial computational savings by reducing the number of sate and adjoint to be solved at every design iteration. The illustrative example of plates with beams supported by columns is the typical one of a large-scale structure to give successful optimum solutions with satisfactory convergence criteria. Hopefully, the method may be applicable to all classes of optimization problems.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.255-263
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• 2005

This paper proposes an efficient boundary-based technique for the shape design sensitivity analysis in various disciplines. An analytical sensitivity formula in the form of a boundary integral is derived based on the continuum formulation for a general functional defined in the problems. The formula can be conveniently used for gradient computation in a variety of shape design problems. The advantage of using a boundary-based method is that the shape variation vectors are needed only on the boundary, not over the whole domain. The boundary shape variation vectors are conveniently computed by using finite. Perturbations of the shape geometry instead of complex analytical differentiation of the geometry functions. The potential flow problems and fillet problem are chosen to illustrate the efficiency of the proposed methodology.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.1
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• pp.106-113
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• 1997

In this paper, we introduce the design method using CAE(Computer Aided Engineering) which is profitable in the compatibility and standardization of the developed product and in the reduction of construction time and price to develop and design a machine equipment. Particularly, we select the standard model to design ot develop from the large machinery to the super precision one, extract the peculiar characters of the model by the close analysis of the physical and technical part, can predict the previous result of experimental characteristics on objective dimensions through the analogical mathematical analysis, and can induce the design model demanded by user investigating optimal data in advance. We present the analogical algorithms and process method of design factors and restriction factors in the systematization design with computer. Then we analyze step functions for each systematization equipment and induce the process of technical data with actuator model.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.6
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• pp.436-445
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• 2001

In this paper, we introduce modulo ( 2$^n$-1) parallel-processing residue multipliers, using Op Amp circuits, and their technological application to designing binary multipliers. The limit of multiplying speed in computational processing is a serious harrier in the advances of VLSI technology. To solve this problem, we implement a class of modulo ( 2$^n$-1) parallel multipliers having superior time complexity to O( log$_2$( log$_2$( log$_2$$^n$))) by applying Op Amp circuits, while investigating their technological application to binary multipliers. Since they have excellent time & area complexity compared with previous parallel multipliers, and are applicable to designing binary multipliers of the same efficiency, such parallel multipliers possess high academic value. Indexing Terms Modular Multipliers. Binary Multipliers. Parallel Processing, Operational Amplifiers, Mersenne Numbers.

• Computational Structural Engineering
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• v.10 no.4
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• pp.315-325
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• 1997

This paper describes the application of discretized continuum-type optimality criteria (DCOC) and the development of optimum design program for the multispan partially prestressed concrete beams. The cost of construction as objective function which includes the costs of concrete, prestressing steel, non-prestressing steel and formwork is minimized. The design constraints include limits on the maximum deflection, flexural and shear strengths, in addition to ductility requirements, and upper and lower bounds on design variables as stipulated by the design Code. Based on Kuhn-Tucker necessary conditions, the optimality criteria are explicitly derived in terms of the design variables-effective depth, eccentricity of prestressing steel and non-prestressing steel ratio. The prestressing profile is prescribed by parabolic functions. The self-weight of the structure is included in the equilibrium equation of the real system, as is the secondary effect resulting from the prestressing force. An iterative procedure and computer program for updating the design variables are developed. Two numerical examples of multispan PPC beams with rectangular cross-section are solved to show the applicability and efficiency of the DCOC-based technique.

• 기계와재료
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• v.22 no.3
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• pp.66-77
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• 2010

나노기술의 발전과 함께 나노소재의 활용과 이를 이용한 나노제품의 개발 및 상용화가 가속되고 있다. 나노소재의 우수한 특성과 이를 이용한 새로운 응용 제품의 연구는 매우 활발하지만, 나노소재가 동반할 수 있는 위해성에 대한 연구와 이를 방지하기 위한 노력은 미미한 상태이다. 본 원고에서는 나노소재를 이용하는 나노제품의 안전성 설계 기술에 대한 동향과 전망을 제시하고자 하며, 구체적으로는 나노소재가 지니는 위해성에 대한 연구 동향, 나노소재의 노출에 대한 전주기적 평가 기술에 대한 연구 동향, 나노제품의 안전성 평가 및 전산해석 그리고 설계기술의 구축에 대한 연구 동향을 제시한다. 가까운 장래에 나노제품이 일반화될 시점에서는 이러한 안전성 설계 기술의 필요성이 크게 대두될 것으로 전망되며, 연구기관이나 관련 기업에서 이에 대한 준비와 인프라 구축이 필요하다.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.126-135
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• 1989

In this study, in order to perform dynamic design of machine tools reasonably and effectively, a method was formulated to be applicable to the structures connected by joints having elasticity and damping by using substructure synthesis method. And to analyze chatter-free performance, a 3 dimensional cutting dynamics theory was used. Computer program package for the dynamic design of machine tools was developed by combining those and spplied to improvement of performance of NC lathe. Also, the optimization in the structural modifications of machine tool substructure was studied by evaluating the effects of the substructural modifications on total system performance.

• Bulletin of the Society of Naval Architects of Korea
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• v.32 no.5
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• pp.33-35
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• 1995

수치 해석적 방법으로서의 CFD(Computational Fluid Dynamics)는 급속한 전산기성능의 발달과 더불어 많은 발전을 거듭하고 있으며, 특히 선박분야에 있어서도 일반선형에 대한 주위의 유 동장해석 및 성능추정, 초기설계에의 응용에서 그 활용성이 입증되고 있다. 따라서, 초고속선에 대하여도, CFD의 대표적 장점이라 할 수 있는 실선에 대한 수치실험이 짧은 시간에 저가의 경비로 가능하다는 것과 그 결과가 모형선 실험결과보다 상세하고 충실한 정보의 확보가능 등을 감안한다면, 앞으로 초기 초고속선 선형개발단계에서 CFD의 적용을 기대해 볼만 할 것이다. 이러한 관점으로부터, 본 고에서는 초고속선의 선형개발에 있어서 CFD의 활용성에 관하여 고 찰해 보고자 한다.