• Title/Summary/Keyword: Pareto 최적해

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A study on reform of public bureaucracy through governance (국가경영을 통한 관료제 개혁에 관한 연구)

  • Choi Rackin
    • Journal of the Korea Society of Computer and Information
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    • v.9 no.3
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    • pp.211-218
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    • 2004
  • It was amazing that efficiency of bureaucratic system, when Marx Weber presented theory of bureaucracy. Now, Government and Bureaucratic organization are confronted with a forked road of change. The purpose of this paper is not so much to force choices among the alternative visions of governance but rather to make the choices available to governments more evident. Any choice of paradigms for government and administration is unlikely to be Pareto optimal, but we should be clear about what we receive and what we sacrifice when we make these judgements about governance. Today, government and public bureaucracy must be changed. There are needed an innovation of government and public bureaucracy. It must be changed concepts from government to governance. Governance is a national management.

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A Study on the Design Method to Optimize an Impeller of Centrifugal Compressor (원심압축기 최적 임펠러 형상설계에 관한 연구)

  • Cho, Soo-Yong;Lee, Young-Duk;Ahn, Kook-Young;Kim, Young-Cheol
    • The KSFM Journal of Fluid Machinery
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    • v.16 no.1
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    • pp.11-16
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    • 2013
  • A numerical study was conducted to improve the performance of an impeller of centrifugal compressor. Nine design variables were chosen with constraints. Only meridional contours and blade profile were adjusted. ANN (Artificial Neural Net) was adopted as a main optimization algorithm with PSO (Particle Swarm Optimization) in order to reduce the optimization time. At first, ANN was learned and trained with the design variable sets which were obtained using DOE (Design of Experiment). This ANN was continuously improved its accuracy for each generation of which population was one hundred. New design variable set in each generation was selected using a non-gradient based method of PSO in order to obtain the global optimized result. After $7^{th}$ generation, the prediction difference of efficiency and pressure ratio between ANN and CFD was less than 0.6%. From more than 1,200 design variable sets, a pareto of efficiency versus pressure ratio was obtained and an optimized result was selected based on the multi-objective function. On this optimized impeller, the efficiency and pressure ratio were improved by 1% and 9.3%, respectively.

Multi-objective Optimization of Fuzzy System Using Membership Functions Defined by Normed Method (노음방법에 의해 정의된 소속함수를 사용한 퍼지계의 다목적 최적설계)

  • 이준배;이병채
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.8
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    • pp.1898-1909
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    • 1993
  • In this paper, a convenient scheme for solving multi-objective optimization problems including fuzzy information in both objective functions and constraints is presented. At first, a multi-objective problem is converted into single objective problem based on the norm method, and a merbership function is constructed by selecting its type and providing the parameters defined by the norm method. Finally, this fuzzy programming problem is converted into an ordinary optimization problem which can be solved by usual nonlinear programming techniques. With this scheme, a designer can conveniently obtain pareto optimal solutions of a fuzzy system only by providing some parameters corresponding to the importance of the objectiv functions. Proposed scheme is simple and efficient in treating multi-objective fuzzy systems compared with and method by with membership function value is provided interactively. To show the validity of the scheme, a simple 3-bar truss example and optimal cutting problem are solved, and the results show that the scheme is very useful and easy to treat multi-objective fuzzy systems.

A Dynamic Pricing Negotiation Model in the Online Ticket Resale Market (온라인 티켓 재판매 시장에서의 Dynamic Pricing 협상모델)

  • Cho, Jae-Hyung
    • The Journal of Society for e-Business Studies
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    • v.14 no.4
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    • pp.133-148
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    • 2009
  • This study has tried to suggest a new model that can effectively redistribute the tickets in the online ticket resale market, while suggesting a new allocation mechanism based on an agent negotiation. To this end, this study has analyzed an auction in the online ticket resale market through Game theory. As a result of new agent mechanism, it has been proved that the price stability of ticket resale market leads to an increase. An agent negotiation helps to stabilize the ticket prices that are usually inclined to rise at auction, benefiting all the participants in the negotiations, consequently showing a Pareto solution. Especially, a framework for a negotiation process is suggested and domain and processes ontology are designed interrelatedly. With this modeling, a possibility of Ontology based agent negotiation is suggested.

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Approximate Multi-Objective Optimization of Robot Casting Considering Deflection and Weight (처짐과 무게를 고려한 주물 프레임의 다중목적 근사최적설계)

  • Choi, Ha-Young;Lee, Jongsoo;Park, Juno
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.954-960
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    • 2012
  • Nowadays, rapidly changing and unstable global economic environments request a lot of roles to engineers. In this situation, product should be designed to make more profit by cost down and to satisfy distinguished performance comparing to other competitive ones. In this research, the optimization design of the industrial robot casting will be done. The weight and deflection have to be reduced as objective functions and stress has to be constrained under some constant value. To reduce time cost, CCD (Central Composite Design) will be used to make experimental design. And RSM (Response Surface Methodology) will be taken to make regression model for objective functions and constraint function. Finally, optimization will be done with Genetic Algorithm. In this problem, the objective functions are multiple, so NSGA-II which is brilliant and efficient for such a problem will be used. For the solution quality check, the diversity between Pareto solutions will be also checked.

Design Optimization of a Pin-Fin Type Heat Sink (핀-휜형 방열판의 설계 최적화)

  • 김형렬;박경우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.10
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    • pp.860-869
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    • 2003
  • Design optimization of the heat sink with 7${\times}$7 square pin-fins is performed numerically using the Computational Fluid Dynamics (CFD) and the Computer Aided Optimization (CAO). In the pin-fins heat sink, the optimum design variables for fin height (h), fin width (w), and fan-to-heat sink distance (c) can be achieved when the thermal resistance ($\theta$$_{j}$) at the junction and the overall pressure drop ($\Delta$p) are minimized simultaneously. To complete the optimization, the finite volume method for calculating the objective functions, the BFGS method for solving the unconstrained non-linear optimization problem, and the weighting method for predicting the multi-objective problem are used. The results show that the optimum design variable for the weighting coefficient of 0.5 are as follows: w=4.653 mm, h=59.215 mm, and c=2.667 mm. In this case, the objective functions are predicted as 0.56K/W of thermal resistance and 6.91 Pa of pressure drop. The Pareto optimal solutions are also presented.re also presented.d.

Multi-Objective Optimization of Flexible Wing using Multidisciplinary Design Optimization System of Aero-Non Linear Structure Interaction based on Support Vector Regression (Support Vector Regression 기반 공력-비선형 구조해석 연계시스템을 이용한 유연날개 다목적 최적화)

  • Choi, Won;Park, Chan-Woo;Jung, Sung-Ki;Park, Hyun-Bum
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.7
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    • pp.601-608
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    • 2015
  • The static aeroelastic analysis and optimization of flexible wings are conducted for steady state conditions while both aerodynamic and structural parameters can be used as optimization variables. The system of multidisciplinary design optimization as a robust methodology to couple commercial codes for a static aeroelastic optimization purpose to yield a convenient adaptation to engineering applications is developed. Aspect ratio, taper ratio, sweepback angle are chosen as optimization variables and the skin thickness of the wing. The real-coded adaptive range multi-objective genetic algorithm code, which represents the global multi-objective optimization algorithm, was used to control the optimization process. The support vector regression(SVR) is applied for optimization, in order to reduce the time of computation. For this multi-objective design optimization problem, numerical results show that several useful Pareto optimal designs exist for the flexible wing.

Beamforming Games with Quantized CSI in Two-user MISO ICs (두 유저 MISO 간섭 채널에서 불완전한 채널 정보에 기반한 빔포밍 게임)

  • Lee, Jung Hoon;Lee, Jin;Ryu, Jong Yeol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.7
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    • pp.1299-1305
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    • 2017
  • In this paper, we consider a beamforming game between the transmitters in a two-user multiple-input single-output interference channel using limited feedback and investigate how each transmitter is able to find a modified strategy from the quantized channel state information (CSI). In the beamforming game, each of the transmitters (i.e., a player) tries to maximize the achievable rate (i.e., a payoff function) via a proper beamforming strategy. In our case, each transmitter's beamforming strategy is represented by a linear combining factor between the maximum ratio transmission (MRT) and the zero forcing (ZF) beamforming vectors, which is the Pareto optimal achieving strategy. With the quantized CSI, the transmitters' strategies may not be valid because of the quantization errors. We propose a modified solution, which takes into account the effects of the quantization errors.

An Optimal Intermodal-Transport Algorithm using Dynamic Programming (동적 프로그래밍을 이용한 최적복합운송 알고리즘)

  • Cho Jae-Hyung;Kim Hyun-Soo;Choi Hyung-Rim;Park Nam-Kyu;Kim So-Yeon
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2006.05a
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    • pp.95-108
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    • 2006
  • Because of rapid expansion of third party logistics, fierce competition in the transportation industry, and the diversification and globalization of transportation channels, an effective transportation planning by means of multimodal transport is badly needed. Accordingly, this study aims to suggest an optimal transport algorithm for the multimodal transport in the international logistics. Cargoes and stopovers can be changed numerously according to the change of transportation modes, thus being a NP-hard problem. As a solution for this problem, first of all, we have applied a pruning algorithm to simplify it, suggesting a heuristic algorithm for constrained shortest path problem to find out a feasible area with an effective time range and effective cost range, which has been applied to the Label Setting Algorithm, consequently leading to multiple Pareto optimal solutions. Also, in order to test the efficiency of the algorithm for constrained shortest path problem, this paper has applied it to the actual transportation path from Busan port of Korea to Rotterdam port of Netherlands.

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An Application of Design of Experiments for Optimization of MOF-235 Synthesis for Acetylene Adsorption Process (아세틸렌 흡착공정용 MOF-235 합성 최적화를 위한 실험 계획법 적용)

  • Cho, Hyungmin;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.31 no.4
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    • pp.377-382
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    • 2020
  • A sequential design of experiments was employed to optimize MOF-235 synthesis for acetylene adsorption process. Two experimental designs were applied: a two-level factorial design for screening and a central composite design, one of response surface methodologies (RSM). In this study, 23 factorial design of experiment was used to evaluate the effect of parameters of synthesis temperature and time, and also mixing speed on crystallinity of MOF-235. Experiments were conducted 16 times follwing MINITAB 19 design software for MOF-235 synthesis. Half-normal, pareto, residual, main and interaction effects were drawn based on the XRD results. The analysis of variance (ANOVA) of test results depicts that the synthesis temperature and time have significant effects on the crystallinity of MOF-235 (response variable). After screening, a central composite design was performed to optimize the acetylene adsorption capacity of MOF-235 based on synthesis conditions. From nine runs designed by MINITAB 19, the result was calculated using the second order model equation. It was estimated that the maximum adsorption capacity (18.7 mmol/g) was observed for MOF-235 synthesized at optimum conditions of 86.3 ℃ and 28.7 h.