• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.377-394
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• 2024

Purpose: To derive the optimal conditions for the Rubber based colloidal suspension manufacturing process, which made using a stirrer, to apply the mixture design method. Methods: We used two process component and one process variable Mixture design to derive the optimal conditions for the process. The response variables were selected for rotational viscometer measures which can represent Rubber based colloidal suspension quality. The input variables were selected as the values of rubber-organic solvent expressed in proportions as process components and stirring amount as a process variable which are controllable factors in the process. Results: Based on the results of the experiment, rubber and organic solvent and the interaction between stirring amount and rubber and the interaction between stirring amount and rubber and organic solvent were significant. Reproducibility of the regression model was confirmed by the observation that the values obtained from the reproducibility experiment fell within the confidence interval. Additionally, the model predictions were found to be in close agreement with the field measurements. Conclusion: In this study, a regression model was developed to predict the viscosity change of colloidal suspensions based on the proportion of rubber based colloidal suspension. The developed regression model can lead to improved product quality.

• Journal of Ocean Engineering and Technology
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• v.35 no.2
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• pp.131-140
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• 2021

The paper deals with comparative study of various surrogate models based approximate optimization in the structural design of the passive type deck support frame under design load conditions. The passive type deck support frame was devised to facilitate both transportation and installation of 20,000 ton class topside. Structural analysis was performed using the finite element method to evaluate the strength performance of the passive type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions. The optimum design problem based on surrogate model was formulated such that thickness sizing variables of main structure members were determined by minimizing the weight of the passive type deck support frame subject to the strength performance constraints. The surrogate models used in the approximate optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. In the context of numerical performances, the solution results from approximate optimization were compared to actual non-approximate optimization. The response surface method among the surrogate models used in the approximate optimization showed the most appropriate optimum design results for the structure design of the passive type deck support frame.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.277-283
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• 2005

Kriging model is widely used as design analysis and computer experiment (DACE) model in the field of engineering design to accomplish computationally feasible design optimization. In general, kriging model has been applied to many engineering applications as an interpolation model because it is usually constructed from deterministic simulation responses. However, when the responses include not only global nonlinearity but also numerical error, it is not suitable to use Kriging model that can distort global behavior. In this research, generalized kriging model that can represent both interpolation and regression is proposed. The performances of generalized kriging model are compared with those of interpolating kriging model for numerical function with error of normal distribution type and trigonometric function type. As an application of the proposed approach, the response of a simple dynamic model with numerical integration error is predicted based on sampling data. It is verified that the generalized kriging model can predict a noisy response without distortion of its global behavior. In addition, the influences of maximum likelihood estimation to prediction performance are discussed for the dynamic model.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.11 s.158
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• pp.1598-1607
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• 2006

The purpose of this study was to analyze the proportion of gathered skirts using a three-dimensional measurement system. And in this experiment, we have attempted to accumulate three-dimensional data of wearing model and find out adequate methods for analyzing shape of clothes. The experimental design consists of two factorial designs. We established three different kinds of fabrics, ratio of gathers. The measurement tool for three-dimensional model was whole body 3D scanner(Exima-WBS2H). Analysis program used in experiment is RapidForm 2004 PP1 and Pattern Design 2000. Data analysis utilizes SPSS WIN 10.0 Package. As the results show, there were different effect of gather and proportion of shapes among the measurements of width, thickness and areas made by different lines of vision in cross-sectional silhouette. And there were difference shapes of section area at each part of gathered skirts between vertical-outline silhouette and vortical-plane silhouette made by gathering conditions. And also the cross-sectional silhouettes and vertical silhouettes were related to shape of clothes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.3
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• pp.251-258
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• 2009

At the stage conceptual design, combat vehicle is classified into three general categories of fire power, mobility and physical properties of system. The present research is restricted to fire power and its optimization. At the stage of conceptual designing of system, it is appropriate to consider major variables affecting fire power - including the weight of bullet, which exerts a direct influence on destroying effect, maximum range which takes long range firing in consideration. To estimate the maximum firing range, a simple interior ballistic and an exterior ballistic model were built by using the lumped parameter method, Le Duc method and point mass trajectory model. Design of experiment and regression analysis was used to derive simulations of fire power. Finally, response surface models were built and design variables were analyzed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.135-147
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• 2005

As automobile technology advances, a smoother ride with less noise is desired. In order to achieve these purposes, a study on the vibration and noise produced by a moving automobile was carried out and a model for tire vibration characteristics which influence the ride performance was developed. The model was verified through simulations and experiments. The developed model was then applied to a half car model and automobile vibrations were analyzed. The effects of tire design parameters on the automobile vibration energy were investigated. The results from laboratory and field tests confirm the validity of the analytical model. The 17-DOF half-car model was built to analyze automobile vibration. The characteristics of the nonlinear model for a shock absorber were applied to this model. The results from the present 17-DOF half car model incorporating the analytical tire model with tire design parameters, were compared with the 5-DOF half car model where the tire was modeled with linear springs. The results of the 17-DOF model are close to the experimental results. Using the 17-DOF model, the influence of tire design parameter were considered. According to the analysis results, the vibrations at seat/body/wheel were predicted by simulation and experiment.

• Environmental Engineering Research
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• v.20 no.4
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• pp.392-396
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• 2015

This work aims to investigate the oily wastewater treatment by the electrocoagulation-flotation (ECF) and propose a mathematical model for the efficiency prediction. Cutting oil was used to prepare the synthetic oily wastewater with submicron droplet sizes. The chemical coagulation by aluminium sulfate was firstly tested following by the electrocoagulation-flotation with aluminium electrodes. Both processes gave the effective treatment performance with the efficiencies higher than 90%. However, the ECF consumed less aluminium dosage as well as produced less sludge, which were its advantage on the chemical coagulation. The performance of the ECF was found to be affected by the current density, oil concentration, and reaction time according to the analysis by the design of experiment (DOE). Finally, the prediction model was proposed by two approaches, including linear and logarithm function. The latter model gave more accuracy prediction results in terms of treatment efficiency and duration in the lag and stable stages.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.436-443
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• 2019

The purpose of this paper is to establish a predictive model by analyzing the influence and correlation of factors affecting the fuel consumption of unmanned helicopters in Captive Flight Test. In this study, a four-factor two-level full factorial experiment was designed and tested using the design of experiments, results were analyzed to derive the main effects and interactions of the factors, and the predictive model was established through regression analysis. It is expected that the results from this study contribute to carrying out Captive Flight Test efficiently and the improvement of the test capability of Electronic Testing Range.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.198-206
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• 1999

An automobile outside rear view mirror system has been analyzed and designed to reduce vibration with a finite element model. model analysis is conducted for the calculation of natural frequencies. harmonic analysis is utilized to estimate the displacements of the glass surface under dynamic loads. The model is verified with the vibration experiment of the parts and the assembled body. The structure of the mirror system is optimized for the robustness defined by the Taguchi concept. At first, many potential design variables are defined. Final design variables are selected based on the amount of contribution on the objective function. That is, sensitive variables are chose. The SN ratio in the Taguchi method is replaced by an objective function with the mean and the standard deviation of the quality characteristic. The defined objective function is appropriate in the structural design in that the vibration displacements are minimized while the robustness is improved.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.2
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• pp.89-94
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• 2001

This paper presents a study of surface roughness prediction model by orthogonal design in turning operation. Regression analysis technique has been used to study the effects of the cutting parameters such as cutting speed, feed depth of cut, and nose radius on surface roughness. An effect of interaction between two parameters on surface roughness has also been investigated. The experiment has been conducted using coated tungsten carbide inserts without cutting fluid. The reliability of the surface roughness model as a function of the cutting parameters has been estimated. The results show that the experimental design used in turning process is a method to estimate the effects of cutting parameters on sur-face roughness.