• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.53-57
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• 2002

Brake tube is considered one of the most important parts in automobile. The shape of brake tube-end has a great influence on the function of brake, and the quality and productivity of brake tube have relation to die design. The forming process of brake tube-end is peformed by hydraulic press forming machine. In this paper, the forming processes of tube-end for automobile is analyzed and designed to make the optimal form of brake tube-end. Also, finite element analysis has been carried out using DEFORM-3D$\^$TM/ to predict the optimal shape of brake tube-end and the results obtained showed the optimal length between punch and chuck is 1.0 ∼ 1.2mm. The shape of tube-end is in good agreement with the finite element simulations and the experimental results.

• 한국기계가공학회지
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• 제16권5호
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• pp.105-112
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• 2017

In this study, plastics were deformed after molding due to the characteristics of the material. The Taguchi experimental design method was utilized to find the molding conditions that minimized deformation of the plastic bezel to be assembled in an automotive steering wheel. The injection molding conditions applied to the experimental design method are the melt temperature, cavity plate coolant temperature, core plate coolant temperature, and cooling time. Each condition was divided into five levels, and a total of 25 experiments were planned. However, instead of performing 25 actual molding experiments, the injection molding analysis was performed using the Moldflow program, and the deformation values for each molding analysis were obtained. The optimal molding conditions were obtained from these deformation values. The actual injection molding experiment using optimal molding conditions was compared with the deformation amount of the current molded product. The deformation was measured using a precise 3D scanner. The deformation amount of the molded product under optimal molding conditions was 16.1% lower than the deformation amount of the current molded product.

• 대한기계학회논문집A
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• 제35권9호
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• pp.1007-1013
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• 2011

상용차용 다층관 벨로우즈는 우수한 유연성과 내구성이 요구되므로 단층으로 제조되는 승용차용 벨로우즈와는 다르게 다층의 형태로 제작된다. 단층 벨로우즈의 유한요소해석과 최적화에 대한 연구는 활발히 진행되고 있으나, 층과 층사이에 갭이 존재하는 다층형 벨로우즈의 유한요소해석과 최적화 연구는 미진하다. 따라서 본 연구에서는 해석의 신뢰성 향상을 위해 다층형 벨로우즈에 적합한 유한요소 모델을 제시하였으며, 다층관 벨로우즈의 형상 최적화를 위해 실험계획법과 D-Optimal 방법에 기반을 둔 순차적 실험계획에 의한 크리깅 메타모델을 적용하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.245-246
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• 2009

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.852-857
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• 2004

A new and efficient method for estimating the statistical moments of a system performance function has been developed. The method consists of two steps: (1) An approximate response surface is generated by a quadratic regression model, and (2) the statistical moments of the regression model are then calculated by experimental design techniques proposed by Seo and $Kwak^{(4)}$. In this approach, the size of experimental region affects the accuracy of the statistical moments. Therefore, the region size should be selected suitably. The D-optimal design and the central composite design are adopted over the selected experimental region for the regression model. Finally, the Pearson system is adopted to decide the distribution type of the system performance function and to analyze structural reliability.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제2권2호
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• pp.133-140
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• 1995

The D-optimal design criterion for precise parameter estimation in nonlinear regression analysis is called the determinant criterion because the determinant of a matrix is to be maximized. In this thesis, we derive the gradient and the Hessian of the determinant criterion, and apply a QR decomposition for their efficient computations. We also propose an approximate form of the Hessian matrix which can be calculated from the first derivative of a model function with respect to the design variables. These equations can be used in a Gauss-Newton type iteration procedure.

• 한국식품과학회지
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• 제53권2호
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• pp.174-180
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• 2021

본 연구는 국내산 복분자와 오디의 활용도를 높이고 고품질의 환을 개발하기 위해 복분자 가루, 오디 가루, 비타민 C 세 가지 재료가 복분자-오디 환의 항산화 특성에 미치는 영향을 조사하기 위해 혼합물 설계법 중 D-optimal mixture design을 이용하였다. 독립변수인 복분자 가루, 오디 가루 및 비타민 C 함량에 따라 복분자-오디 환의 총 페놀 및 플라보노이드 함량, FRAP이 linear 모델, DPPH 라디컬 소거활성은 quadratic 모델로 결정되었으며 회귀식은 p-value의 값이 각각 0.0481, <0.0001, <0.0001 및 0.0387로 유의성이 인정되었다. 총 페놀 함량은 비타민 C 첨가량에 영향을 크게 받았지만 복분자 가루 및 오디 가루 첨가량이 부정적인 영향을 주지 않는 것으로 나타났다. 총 플라보노이드 함량은 복분자 가루의 함량이 증가할수록 크게 높아지는 것으로 나타났다. DPPH 라디컬 소거활성은 비타민 C 첨가량이 높을수록 증가하였으며, 복분자 가루의 첨가량이 너무 낮아지면 감소하는 것으로 나타났다. FRAP 활성은 비타민 C와 오디가루 첨가량이 긍정적인 영향을 주는 것으로 드러났다. 이러한 결과와 desirability를 바탕으로 두 개의 복분자-오디 환 배합비가 가능할 것으로 도출되었지만 이 둘 중에서 Formulation 1 (복분자 가루 35%, 오디가루 10%, 비타민 C 10%)이 desirability가 0.8 이상으로 제품 품질이 적합하고 우수하여 최적 배합 비율로 설정하였다.

• 전력전자학회논문지
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• 제24권4호
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• pp.259-267
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• 2019

An active clamp flyback (ACF) converter applies a clamp circuit and circulates the energy of leakage inductance to the input side, thereby achieving a zero-voltage switching (ZVS) operation and greatly reducing switching losses. The switching losses are further reduced by applying a gallium nitride field effect transistor (GaN-FET) with excellent switching characteristics, and ZVS operation can be accomplished under light load with boundary conduction mode (BCM) operation. Optimal design is performed on the basis of loss analysis by selecting magnetization inductance based on BCM operation and a clamp capacitor for loss reduction. Therefore, the size of the reactive element can be reduced through high-frequency operation, and a high-efficiency and high-power-density converter can be achieved. This study proposes an optimal design for a high-efficiency and high-power-density BCM ACF converter based on GaN-FETs and verifies it through experimental results of a 65 W-rated prototype.

• Current Optics and Photonics
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• 제8권1호
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• pp.45-55
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• 2024

A fiber spool with ultra-low vibration sensitivity has been demonstrated for the ultra-narrow-linewidth fiber-stabilized laser by the multi-object orthogonal experimental design method, which can achieve the optimization object and analysis of influence levels without extensive computation. According to a test of 4 levels and 4 factors, an L₁₆ (4⁴) orthogonal table is established to design orthogonal experiments. The vibration sensitivities along the axial and radial directions and the normalized sums of the vibration sensitivities are determined as single objects and comprehensive objects, respectively. We adopt the range analysis of object values to obtain the influence levels of the four design parameters on the single objects and the comprehensive object. The optimal parameter combinations are determined by both methods of comprehensive balance and evaluation. Based on the corresponding fractional frequency stability of ultra-narrow-linewidth fiber-stabilized lasers, we obtain the final optimal parameter combination A3B1C2D1, which can achieve the fiber spool with vibration sensitivities of 10^-12/g magnitude. This work is the first time to use an orthogonal experimental design method to optimize the vibration sensitivities of fiber spools, providing an approach to design the fiber spool with ultra-low vibration sensitivity.

• 약학회지
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• 제43권6호
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• pp.689-695
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• 1999

Hydrotalcite was prepared by reacting with sodium carbonate, magnesium oxide and aluminum sulfate solutions in this study. The optimum synthesis conditions based on the yield of the product were established by applying Box-Wilson experimental design. It was found that the optimum synthesis conditions of hydrotalcite were as follows; reacting temperature : 48~63$^{\circ}C$, concentration of reactant solution : about 20%, molar concentration ratio of two reactants [MgO]/[Al. sulfate] ; 7.35~8.1, temperature of washing water : 34.4~37.4$^{\circ}C$, drying temperature : 74~81.5$^{\circ}C$. The physicochemical properties of hydrotalcite as medicine were studied by use of chemical analysis, D.S.C. thermogram, bulk volume test and acid consuming capacity measurements.