• 제목/요약/키워드: design method

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Pareto 최적점 기반 다목적함수 기법 개발에 관한 연구 (Development of a Multi-objective function Method Based on Pareto Optimal Point)

  • 나승수
    • 대한조선학회논문집
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    • 제42권2호
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    • pp.175-182
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    • 2005
  • It is necessary to develop an efficient optimization technique to optimize the engineering structures which have given design spaces, discrete design values and several design goals. As optimization techniques, direct search method and stochastic search method are widely used in designing of engineering structures. The merit of the direct search method is to search the optimum points rapidly by considering the search direction, step size and convergence limit. And the merit of the stochastic search method is to obtain the global optimum points by spreading point randomly entire the design spaces. In this paper, a Pareto optimal based multi-objective function method (PMOFM) is developed by considering the search direction based on Pareto optimal points, step size, convergence limit and random search generation . The PMOFM can also apply to the single objective function problems, and can consider the discrete design variables such as discrete plate thickness and discrete stiffener spaces. The design results are compared with existing Evolutionary Strategies (ES) method by performing the design of double bottom structures which have discrete plate thickness and discrete stiffener spaces.

등압법과 T-method를 이용한 공조시스템 배관 설계에 관한 연구 (A Study on the Duct Design of HVAC System Using the Equal Friction Method and the T-method)

  • 박준석;최길환;조대승
    • 대한조선학회논문집
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    • 제46권4호
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    • pp.435-443
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    • 2009
  • Optimal duct design of a HVAC system requires analysis technology to accurately evaluate its pressure losses, flow rate and velocity for making a compromised design among fan capacity and duct size affecting initial manufacturing and operation costs, and noise induced by the HVAC system. In this paper, we carry out initial duct design using the equal friction method. Using the result, the T-method is applied for accurate analysis of flow rate. Then, the duct size is modified using the difference between the required and the calculated flow rate, which can guarantee required flow rate, reduce the pressure unbalance among duct paths and lead to select optimal fan performance. To verify the validity and effectiveness of the proposed design method, an example for HVAC system design including noise analysis is demonstrated.

EFFECTIVE REINFORCEMENT OF S-SHAPED FRONT FRAME WITH A CLOSED-HAT SECTION MEMBER FOR FRONTAL IMPACT USING HOMOGENIZATION METHOD

  • CHO Y.-B.;SUH M.-W.;SIN H.-C.
    • International Journal of Automotive Technology
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    • 제6권6호
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    • pp.643-655
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    • 2005
  • The frontal crash optimization of S-shaped closed-hat section member using the homogenization method, design of experiment (DOE) and response surface method (RSM) was studied. The optimization to effectively absorb more crash energy was studied to introduce the reinforcement design. The main focus of design was to decide the optimum size and thickness of reinforcement. In this study, the location of reinforcement was decided by homogenization method. Also, the effective size and thickness of reinforcements was studied by design of experiments and response surface method. The effects of various impact velocity for reinforcement design were researched. The high impact velocity reinforcement design showed to absorb the more crash energy than low velocities design. The effect of size and thickness of reinforcement was studied and the sensitivity of size and thickness was different according to base thickness of model. The optimum size and thickness of the reinforcement has shown a direct proportion to the thickness of base model. Also, the thicker the base model was, the effect of optimization using reinforcement was the bigger. The trend curve for effective size and thickness of reinforcement using response surface method was obtained. The predicted size and thickness of reinforcement by RSM were compared with results of DOE. The results of a specific dynamic mean crushing loads for the predicted design by RSM were shown the small difference with the predicted results by RSM and DOE. These trend curves can be used as a basic guideline to find the optimum reinforcement design for S-shaped member.

Boundary Method for Shape Design Sensitivity Analysis in Solving Free-Surface Flow Problems

  • Choi Joo Ho;Kwak H. G.;Grandhi R. V.
    • Journal of Mechanical Science and Technology
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    • 제19권12호
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    • pp.2231-2244
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    • 2005
  • An efficient boundary-based optimization technique is applied in the numerical computation of free surface flow problems, by reformulating them into the equivalent optimal shape design problems. While the sensitivity in the boundary method has mainly been calculated using the boundary element method (BEM) as an analysis means, the finite element method (FEM) is used in this study because of its popularity and easy-to-use features. The advantage of boundary method is that the design velocity vectors are needed only on the boundary, not over the whole domain. As such, a determination of the complicated domain design velocity field, which is necessary in the domain method, is eliminated, thereby making the process easy to implement and efficient. Seepage and supercavitating flow problem are chosen to illustrate the accuracy and effectiveness of the proposed method.

Sensitivity Analysis by Parametric Study of Load Factor for a Concrete Box Girder Railway Bridge Using Limit State Design

  • Yeo, Inho;Sim, Hyung-Bo;Kim, Daehwan;Kim, Yonghan
    • International Journal of Railway
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    • 제8권1호
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    • pp.5-9
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    • 2015
  • Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

동작 정보를 갖는 가상설비 데이터 재활용 방법론 (A Method of Reusing Kinematic Information for Virtual Facilities)

  • 고민석;신혜선;왕지남;박상철
    • 한국CDE학회논문집
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    • 제16권4호
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    • pp.305-313
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    • 2011
  • This paper proposes a method for reusing kinematic design data for virtual facilities, Making a virtual model of a facility involves two major activities: geometric design (virtual model visualization) and kinematic design that should be remodeled frequently whenever design changes occur, Conventionally, a virtual model of an automated facility focuses on the design level, which mainly deals with design verification, alternative comparison, and geometric model diagnosis, Although a design level model can be designed with the information of past models from PLM system, a simulation level model is not sufficient utilized to be reused for kinematic design purpose, We propose a method for reusing kinematic information of a past simulation model to cope with this problem, We use the concept or the 'center of mass', which is a point representing the mean position of the matter in a body or system. And we also use comparison method of a boundary box to identity which 3D objects have to be involved from the design model to a link structure that is contained in the simulation model. Because a proposed method only use not a historical approach but a geometrical approach, it is more effective to apply to the field.

Optimum Design of Ship Design System Using Neural Network Method in Initial Design of Hull Plate

  • Kim, Soo-Young;Moon, Byung-Young;Kim, Duk-Eun
    • Journal of Mechanical Science and Technology
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    • 제18권11호
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    • pp.1923-1931
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    • 2004
  • Manufacturing of complex surface plates in stern and stem is a major factor in cost of a preliminary ship design by computing process. If these hull plate parts are effectively classified, it helps to compute the processing cost and find the way to cut-down the processing cost. This paper presents a new method to classify surface plates effectively in the preliminary ship design using neural network. A neural-network-based ship hull plate classification program was developed and tested for the automatic classification of ship design. The input variables are regarded as Gaussian curvature distributions on the plate. Various applicable rules of network topology are applied in the ship design. In automation of hull plate classification, two different numbers of input variables are used. By observing the results of the proposed method, the effectiveness of the proposed method is discussed. As a result, high prediction rate was achieved in the ship design. Accordingly, to the initial design stage, the ship hull plate classification program can be used to predict the ship production cost. And the proposed method will contribute to reduce the production cost of ship.

증강현실 콘텐츠의 맥락 기반 디자인 방법론 연구 (Context-based Design Methodology For Augmented Reality Contents)

  • 이지혜
    • 한국콘텐츠학회논문지
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    • 제17권2호
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    • pp.249-257
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    • 2017
  • 본 연구는 장소에 기반한 증강현실 서비스의 콘텐츠 디자인을 위해 사용자의 맥락을 기반으로 한 통합적 디자인 방법론에 대해 논의하고자 한다. 모바일 서비스에 관련한 미디어 콘텐츠는 다이내믹한 환경과 사용자의 맥락을 고려하여 디자인이 되어야 하며, 이에 따라 증강현실 콘텐츠를 위한 맥락 기반 디자인 방법론을 제안하고자 하였다. 디자인 방법론 연구를 위해 새로운 디자인 방법론을 제시하기 위한 연구사례들을 파악하고 여러 방법론의 통합적 접근방식을 이해하였다. 이 방법에 기반하여, 맥락 기반 디자인 방법론들을 조사하고 이를 통합하고자 하였다. 맥락 기반 디자인 방법론에는 두 가지 상반된 연구방법이 있으며, 두 연구사례들을 분석하고 장점을 통합함으로써 종합적인 맥락 기반 디자인 방법론을 제안하고자 하였다. 이는 새로운 기술이 적용되고 있는 증강현실 콘텐츠 제작에 있어 향후 디자인 방법론으로써 이용하는 데 도움이 되고자 하는 목적을 지니고 있다.

A hybrid simulated annealing and optimality criteria method for optimum design of RC buildings

  • Li, Gang;Lu, Haiyan;Liu, Xiang
    • Structural Engineering and Mechanics
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    • 제35권1호
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    • pp.19-35
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    • 2010
  • This paper proposes a hybrid heuristic and criteria-based method of optimum design which combines the advantages of both the iterated simulated annealing (SA) algorithm and the rigorously derived optimality criteria (OC) for structural optimum design of reinforced concrete (RC) buildings under multi-load cases based on the current Chinese design codes. The entire optimum design procedure is divided into two parts: strength optimum design and stiffness optimum design. A modified SA with the strategy of adaptive feasible region is proposed to perform the discrete optimization of RC frame structures under the strength constraints. The optimum stiffness design is conducted using OC method with the optimum results of strength optimum design as the lower bounds of member size. The proposed method is integrated into the commercial software packages for building structural design, SATWE, and for finite element analysis, ANSYS, for practical applications. Finally, two practical frame-shear-wall structures (15-story and 30-story) are optimized to illustrate the effectiveness and practicality of the proposed optimum design method.

구름 베어링 설계를 위한 유전 알고리듬 기반 조합형 최적설계 방법 (Genetic-Based Combinatorial Optimization Method for Design of Rolling Element Bearing)

  • 윤기찬;최동훈;박창남
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2001년도 제34회 추계학술대회 개최
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    • pp.166-171
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    • 2001
  • In order to improve the efficiency of the design process and the quality of the resulting design for the application-based exclusive rolling element bearings, this study propose design methodologies by using a genetic-based combinatorial optimization. By the presence of discrete variables such as the number of rolling element (standard component) and by the engineering point of views, the design problem of the rolling element bearing can be characterized by the combinatorial optimization problem as a fully discrete optimization. A genetic algorithm is used to efficiently find a set of the optimum discrete design values from the pre-defined variable sets. To effectively deal with the design constraints and the multi-objective problem, a ranking penalty method is suggested for constructing a fitness function in the genetic-based combinatorial optimization. To evaluate the proposed design method, a robust performance analyzer of ball bearing based on quasi-static analysis is developed and the computer program is applied to some design problems, 1) maximize fatigue life, 2) maximize stiffness, 3) maximize fatigue life and stiffness, of a angular contact ball bearing. Optimum design results are demonstrate the effectiveness of the design method suggested in this study. It believed that the proposed methodologies can be effectively applied to other multi-objective discrete optimization problems.

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