• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 추계학술대회 논문집
• /
• pp.286-289
• /
• 2008

Mass of generator is one of the most important characteristic value especially direct drive type wind turbine. This paper introduce how to decease mass of generator rotor frame without declining generator performance. To obtain optimal design of rotor frame, sensitivity analysis using Taguchi method and RSM(response surface method) are have been performed.

• Advances in concrete construction
• /
• 제11권4호
• /
• pp.285-298
• /
• 2021

This study focused on experimental evaluation of mechanical properties of pervious concrete mixtures with the aim of achieving higher values of strength while considering the associated costs. The effectiveness of key parameters, including cement content, water to cement ratio (W/C), aggregate to cement ratio (A/C), and sand replacement was statistically analyzed using paired-samples t-test, Taguchi method and one-way ANOVA. Taguchi analysis determined that in general, the role of W/C was more significant in increasing strength, both compressive and flexural, than cement content and A/C. It was found that increase in replacing percent of coarse aggregate with sand could undermine specimens to percolate water, though one-way ANOVA analysis determined statistically significant increases in values of strength of mixtures. Cost analysis revealed that higher strengths did not necessarily correspond to higher costs; in addition, increasing the cement content was not an appropriate scenario to optimize both strength and cost. In order to obtain the optimal values, response surface method (RSM) was carried out. RSM optimization helped to find out that W/C of 0.40, A/C of 4.0, cement content of about 330 kg/m3 and replacing about 12% of coarse aggregate with sand could result in the best values for strength and cost while maintaining adequate permeability.

• 품질경영학회지
• /
• 제41권2호
• /
• pp.249-260
• /
• 2013

Purpose: The main objective of this paper is to propose an RD method by developing a neural network (NN)-based estimation approach in order to provide an alternative aspect of response surface methodology (RSM). Methods: A specific modeling procedure for integrating NN principles into response function estimations is identified in order to estimate functional relationships between input factors and output responses. Finally, a comparative study based on simulation is performed as verification purposes. Results: This simulation study demonstrates that the proposed NN-based RD method provides better optimal solutions than RSM. Conclusion: The proposed NN-based RD approach can be a potential alternative method to utilize many RD problems in competitive manufacturing nowadays.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.700-703
• /
• 2004

A reliability analysis and design procedure based on the design of experiment (DOE) is combined with the response surface method (RSM) for numerical efficiency. The procedure established is based on a 3$^n$ full factorial DOE for numerical quadrature using explicit formula of optimum levels and weights derived for general distributions. The full factorial moment method (FFMM) shows good performance in terms of accuracy and ability to treat non-normally distributed random variables. But, the FFMM becomes very inefficient because the number of function evaluation required increases exponentially as the number of random variables considered increases. To enhance the efficiency, the response surface moment method (RSMM) is proposed. In RSMM, experiments only with high probability are conducted and the rest of data are complemented by a quadratic response surface approximation without mixed terms. The response surface is updated by conducting experiments one by one until the value of failure probability is converged. It is calculated using the Pearson system and the four statistical moments obtained from the experimental data. A measure for checking the relative importance of an experimental point is proposed and named as influence index. During the update of response surface, mixed terms can be added into the formulation.

• 동력기계공학회지
• /
• 제21권3호
• /
• pp.85-92
• /
• 2017

Global air traffic is forecast to grow at an average annual rate of around 5% in the next 20 years. The continuous growth of air traffic and raised environmental awareness put increasing pressure on aero engine manufacturers to reduce fuel burn and emissions. NEWAC are a new integrated program of the European Union with focus on innovative core engine concepts to achieve this problem. In this paper, Within NEWAC, active core engine configurations will be investigated. the investigation is focused on the optimal design of the CAC heat exchanger for active core. For optimal design of he CAC heat exchanger, the HTFS of basic design of heat exchanger are analyzed so as to proceed an optimization routines based on Response Surface Method(RSM) and Design of Experiment(DOE). As a result, CAC heat exchanger optimized by 1.0314 lb/s mass flow rate and 3.9058 mm TP of tube layout and 206.8181 mm height of heat exchanger and 918 tube number for heat transfer and pressure drop. We confirm the design optimization using RSM and DOE is useful on complex structure of heat exchanger.

• Wind and Structures
• /
• 제21권6호
• /
• pp.597-607
• /
• 2015

With an increasing demand of a renewable energy, new offshore wind turbine farms are being planned in some parts of the world. Foundation installation asks a significant cost of the total budget of offshore wind turbine (OWT) projects. Hence, a cost reduction from foundation parts is a key element when a cost-efficient designing of OWT budget. Mono-piles have been largely used, accounting about 78% of existing OWT foundations, because they are considered as a most economical alternative with a relatively shallow-water, less than 30 m of seawater depth. OWT design standards such as IEC, GL, DNV, API, and Eurocode are being developed in a form of reliability based limit state design method. In this paper, reliability analysis using the response surface method (RSM) and numerical simulation technique for an OWT mono-pile foundation were performed to investigate the sensitivities of mono-pile design parameters, and to find practical implications of RSM reliability analysis.

• Nuclear Engineering and Technology
• /
• 제28권6호
• /
• pp.507-521
• /
• 1996

Quantification of uncertainties in the source term estimations by a large computer code, such as MELCOR and MAAP, is an essential process of the current Probabilistic safety assessment. The main objective of the present study is to investigate the applicability of a combined procedure of the response surface method (RSM) based on input determined from a statistical design and the Latin hypercube sampling (LHS) technique for the uncertainty analysis of CsI release fractions under a Hypothetical severe accident sequence of a station blackout at Younggwang nuclear power plant using MAAP3. OB code as a benchmark problem. On the basis of the results obtained in the present work, the RSM is recommended to be used as a principal tool for an overall uncertainty analysis in source term quantifications, while using the LHS in the calculations of standardized regression coefficients (SRC) and standardized rank regression coefficient (SRRC) to determine the subset of the most important input parameters in the final screening step and to check the cumulative distribution functions obtained by RSM. Verification of the response surface model for its sufficient accuracy is a prerequisite for the reliability of the final results that can be obtained by the combined procedure proposed in the present work.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.453-458
• /
• 2005

Weight minimization of double-deck train carbody is imperative to reduce cost and extend life-time of train. It is required to decide 36 thickness of aluminum extruded panels. However, the design variables are two many to tract. moreover, one execution of structural analysis of double-deck carbody is time-consuming. Therefore, we adopt approximation technique to save computational cost of optimization process. Response surface model is used to apporximate static response of double-deck carbody. To obtain plausible response surface model, orthogonal array is empolyed as design of experiment(DOE). Design improvement by approximate model-based optimization is described. Accuracy and efficiency of optimization by using response surface model are discussed.

• International Journal of Automotive Technology
• /
• 제8권1호
• /
• pp.93-102
• /
• 2007

The frontal crash optimization of an engine room member using the response surface method was studied. The engine room member is composed of the front side member and the sub-frame. The thicknesses of the panels on the front side member and the sub-frame were selected as the design variables. The purpose of the optimization was to reduce the weight of the structure, under the constraint that the objective quantity of crash energy is absorbed. The response surface method was used to approximate the crash behavior in mathematical form for optimization procedure. To research the effect of the regression method, two different methodologies were used in constructing the response surface model, the least square method and the moving least square method. The optimum with the two methods was verified by the simulation result. The precision of the surrogate model affected the optimal design. The moving least square method showed better approximation than the least square method. In addition to the deterministic optimization, the reliability-based design optimization using the response surface method was executed to examine the effect of uncertainties in design variables. The requirement for reliability made the optimal structure be heavier than the result of the deterministic optimization. Compared with the deterministic optimum, the optimal design using the reliability-based design optimization showed higher crash energy absorption and little probability of failure in achieving the objective.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권10호
• /
• pp.494-500
• /
• 2001

This paper presents the shape optimization to minimize the BEMF(Back Electro-Motive Force) harmonics of PM type synchronous generators. RSM(Response Surface Methodology) is well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. In this paper, RSM is used to find the optimal solution. The 2D-Finite Element Method is used to obtain the observer data of the BEMF and SQP(Sequential Quadratic Problem method) is used to solve the constrained nonlinear optimization problem.