• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.17-23
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• 2002

The present paper describes the optimum inverse design of 2-D linear cascade airfoil. The pressure coefficient of an airfoil surface is taken as the objective function, and non-orthogonal incompressible Navier-Stokes equation is applied to calculate the pressure coefficient. Both of steepest descent and conjugate gradient method have been used to make the objective function go to zero. The 1st order finite differential method is applied to the searching direction and the golden section method is used to compute the searching distance. As a result of the present work, a good convergence to the target airfoil has been obtained.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.161-166
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• 2020

This paper suggests an extension of the unified Bayesian Tikhonov regularization method. The unified method establishes the relationship between Tikhonov regularization parameter and Bayesian hyper-parameters, and presents a formula for obtaining the regularization parameter using the maximum posterior probability and the evidence framework. When the dimension of the data matrix is m by n (m >= n), we derive that the total misfit has the range of m ± n instead of m. Thus the search range is extended from one to 2n + 1 integer points. Golden section search rather than linear one is applied to reduce the time. A new benchmark for optimizing relative error and new model selection criteria to target it are suggested. The experimental results show the effectiveness of the proposed method in the image restoration problem.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.63-69
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• 2017

The golden section search method is widely used to optimize a single design variable in many fields due to its superior advantages of search. In this paper, a new direct search method is proposed by modifying the search structure of the golden section search method; thus, it can be adapted in the optimization of a single design variable for the injection molding process. This proposed method is applied to determine an optimal gate position for the injection molding of a bezel of an automated teller machine for minimizing the injection pressure. Thus, an optimal gate position where the injection pressure is decreased by 4.5 MPa to that of the initial position was obtained with a small number of simulations. It is anticipated that the current proposed search method can be utilized as a practical tool for optimizing single variables for injection molding design.

• The Science & Technology
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• v.9 no.7 s.86
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• pp.8-8
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• 1976

미국화성탐색선 "바이킹" 1호가 7월 20일 오후 8시 53분(한국시간) 드디어 화성 크리세 플래니티아(황금의 땅)에 착륙성공하였다. 10억여불이 투자된 "바이킹" 1호의 주목적은 화성에 생명체가 있는가를 과명하는데 있다. 모선인 바이킹궤도순회선과 자선인 화성 착륙선은 화성을 감싸고 있는 신비의 너울을 벗기기 위한 과학적 시험을 하게된다. 궤도순회선은 영상화시험, 적외선 열지도 작성, 수증기검출 무선과학을 위한 시험을 담당하게 되며 착륙선은 화성표면, 대기권, 기타 천문학연구, 대상물체의 영상하시험, 무기화학시험관측, 지진조사, 화성모래알의 자성시험을 하게된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1613-1616
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• 2005

In this paper, we developed an algorithm of generating cam contour curve for hinge mechanism of folder-type mobile phone. The main feature of this hinge mechanism is that we can operate uniform torque to open or close the mobile phone. We divided the opening or closing intervals of the cam into finite sub-intervals, and then we determined the cam contour curve of each sub-interval as a parabolic curve. Finally, these finite parabolic curves form the total cam contour. We can design single cam, which composed moving cam with contour curve and fixed cam that plays only roller, and twin cam with contour curve that is made up the pair of two cams symmetrically.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.72-77
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• 1997

In the temperature analysis of hot metal forming process, the heat transfer conditions between the work-piece and the tool have improtant influences upon the temperature distribution. The accuracy of thermal analysis depends on the proper description of boundary conditions including heat transfer. At the contact surface of two materials with different temperatures, this requires the knowledge of the overall heat transfer coefficient. In order to determine the overall heat transfer coefficient, a technique is developed. The technique involves temperature measurement by using thermocouples during hot upsetting operations and finite element computation. The overall heat transfer coefficient is determined using a non-linear optimization technique.

• Journal of The Korean Association For Science Education
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• v.37 no.2
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• pp.323-334
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• 2017

Current science education aims to guide students as future responsible citizens to make informed decisions on socioscientific issues (SSI). In the authors' previous study, it was found that conceptions of nature of technology (NOT) were explicitly represented in various contexts of SSI with differentiated levels of understanding, and cases of the informed NOT understanding included the key features of well-reasoned SSI decision-making. Therefore, enhancing NOT understanding could be one of the elements to leverage students' informed SSI decision-making. In this study, we developed a rubric to assess NOT understanding in the context of SSI and applied it to evaluate the impact of SSI instruction. Participants were 58 college students who took an SSI course for 6 weeks. Before and after the SSI course, they were asked to write decision-making essays on the Golden Rice issue (a type of genetically modified food). As a result of analyzing the pre- and post decision-making essay using the rubric, it was found that NOT understanding was improved after the SSI course; in addition, the salient patterns of NOT changes were analyzed in detail in order to gauge the influence of the SSI classes. Implications for science education were discussed.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.17-29
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• 2008

A volume-delay function(VDF) has been used to describe the relation between traffic volumes and delay experienced by travelers on the roads traveling from origin to destination, which has been usually adopted in traffic assignment. For the purpose of more precise description of traffic pattern, we have to estimate the parameters of VDF in advance. This paper presents a methodology for estimating the parameters, which combined with golden section method. By using the method we have estimated the parameters with real data based on KTDB(2006), and validated them. Compared to the existing values of the parameters, newly estimated values are found to be closer to real world.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.215-221
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• 2012

In this paper, we introduce an optimization method to improve pursuit performance of a pursuer in a pursuit-evasion game (PEG). Pursuers build a probability map and employ a hybrid pursuit policy which combines the merits of local-max and global-max pursuit policies to search and capture evaders as soon as possible in a 2-dimensional space. We propose an episodic parameter optimization (EPO) algorithm to learn good values for the weighting parameters of a hybrid pursuit policy. The EPO algorithm is performed while many episodes of the PEG are run repeatedly and the reward of each episode is accumulated using reinforcement learning, and the candidate weighting parameter is selected in a way that maximizes the total averaged reward by using the golden section search method. We found the best pursuit policy in various situations which are the different number of evaders and the different size of spaces and analyzed results.