• 한국정밀공학회지
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• 제20권2호
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• pp.209-217
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• 2003

In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system are proposed for the reduction of the vibration. In the respect of modeling, the spin-coater system is considered to be composed of servomotor, spindle, supporting base and so on. Each component of model is combined and derived to 3 dimensional equations. The combined model is verified by experimental values of actual system in the frequency domain. By direct differentiation of the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, rotational stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables are selected from the sensitivity analysis.

• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.65-69
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• 2007

A design of experiments was applied in order to investigate the effect of processing variables in UV irradiation on the electrical/optical properties in indium-zinc oxide thin films, The processing variables, equivalently input variables are listed as UV irradiation time, oxygen flow rate, and chamber pressure. The statistical significance of Ultra Violet (UV) treatment was confirmed using a paired-t test. The full factorial $2^3$ design was employed to determine significant main and interaction effects in UV irradiation process. The chamber pressure and the interaction between UV irradiation time and $O_2$ flow rate were found to be statistically significant at the significance level of 0.1. Furthermore, the optimized approach was proposed in achieving the improved conductivity after UV irradiation.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.369-378
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• 2010

The creation of the hydraulic turbine flow factor map will undoubtedly benefit its design by decreasing both the design cycle time and product cost. In this paper, the geometry and flow variables, which effectively affect the flow factor, are proposed, analyzed and determined. These flow variables are further used to create the operating condition maps by using different model approaches categorized into Response Surface Method (RSM) and Artificial Neural Network (ANN). The accuracies of models created by different approaches are compared and the performances of model approaches are analyzed. The influences of chosen variables and the combination of Principle Component Analysis (PCA) and model approaches are also studied. The comparison results between predicted and actual flow factors suggest that two-hidden-layer Feed-forward Neural Network (FFNN), and one.hidden-layer FFNN with PCA has the best performance on forming this mapping, and are accurate sufficiently for hydraulic turbine design.

• 산업공학
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• 제5권1호
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• pp.25-34
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• 1992

A study to analyze and solve inherent problems of a pilot cola machine has been presented in this paper. The product considered in this study involves at least 16 variables(factors) which simultaneously affect the product performance. For this multi-variate statistical problem, we first carefully examined their relationships and selected four variables considered as the most important. We have taken Taguchi's parameter design approach, specifically the $L_8\:(2^7)$ orthogonal array, and determined the optimal levels of the selected variables through the analysis of the experimental results. Finally, we conclude this study with providing general comments drawn from the analysis and verification experiments.

• 한국정보처리학회논문지
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• 제6권10호
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• pp.2693-2706
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• 1999

Reengineering to object-oriented system is needed to maintain the system and satisfy requirements of structure change. Target systems which should be reengineered to object-oriented system are difficult to change because these systems have no design document or their design document is inconsistent of source code. Using design document to identifying objects for these systems is improper. There are several researches which identify objects through procedural source code analysis. In this paper, we propose automatic object identification method based on clustering of VTFG(Variable-Type-Function Graph) which represents relations among variables, types, and functions. VTFG includes relations among variables, types, and functions that may be basis of objects, and weights of these relations. By clustering related variables, types, and functions using their weights, our method overcomes limit of existing researches which identify too big objects or objects excluding many functions. The method proposed in this paper minimizes user's interaction through automatic object identification and make it easy to reenginner procedural system to object-oriented system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.421-428
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• 1998

Sensitivity analysis of suspension elements of an articulated bogie for light railway vehicles is presented. The ride, stability and safety are used as dynamic performance index. Suspension elements of 10 and a conicity of wheel are used as design variables, To analyze sensitivity of design variables, the railway vehicle dynamics analysis program AGEM is used. The results shows that the secondary suspension elements have a strong effect on ride and the primary suspension elements have a moderate effect on ride. Conicity of wheel has a strong effect on the stability, The safety is not effected by all the design variables.

• Steel and Composite Structures
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• 제23권4호
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• pp.445-452
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• 2017

This study intends to improve the structural details of the anchors in the conventional CFT column-to-foundation connection. To that goal, finite element analysis is conducted with various design variables (number and embedded length of deformed bars, number, aspect ratio, height ratio and thickness ratio of ribs) selected based upon the results of loading test and strength evaluation. The finite element analysis is performed using ABAQUS and the analytical results are validated by comparison with the load-displacement curves obtained through loading test applying axial and transverse loads. The behavioral characteristics of the numerical model according to the selected design variables are verified and the corresponding results are evaluated.

• 품질경영학회지
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• 제39권3호
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• pp.400-411
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• 2011

Process variables are factors in an experiment that are not mixture components but could affect the blending properties of the mixture ingredients. For example, the effectiveness of an etching solution which is measured as an etch rate is not only a function of the proportions of the three acids that are combined to form the mixture, but also depends on the temperature of the solution and the agitation rate. Efficient designs for the mixture components-process variables experiments depend on the mixture components-process variables model which is called a combined model. We often use the product model between the canonical polynomial model for the mixture and process variables model as a combined model. In this paper we propose three starting models for the mixture components-process variables experiments. One of the starting model we are considering is the model which includes product terms up to cubic order interactions between mixture effects and the linear & pure quadratic effect of the process variables from the product model. In this paper, we propose a method for finding robust designs and practical designs with respect to D-, G-, and I-optimality for the various starting combined models and then, we find practically efficient and robust designs for estimating the regression coefficients for those models. We find the prediction capability of those recommended designs in the case of three components and three process variables to be good by checking FDS(Fraction of Design Space) plots.

• Structural Engineering and Mechanics
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• 제39권6호
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• pp.877-893
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• 2011

Response spectra of earthquake ground motions are important in the earthquake-resistant design and reliability analysis of structures. The formulation of the response spectrum in the frequency domain efficiently computes and evaluates the stochastic response spectrum. The frequency information of the excitation can be described using different functional forms. The shapes of the calculated response spectra of the excitation show strong magnitude and site dependency, but weak distance dependency. In this paper, to compare the effect of the earthquake ground motion variables, the contribution of these sources of variability to the response spectrum's uncertainty is calculated by using a stochastic analysis. The analytical results show that earthquake source factors and soil condition variables are the main sources of uncertainty in the response spectra, while path variables, such as distance, anelastic attenuation and upper crust attenuation, have relatively little effect. The presented formulation of dynamic structural response in frequency domain based only on the frequency information of the excitation can provide an important basis for the structural analysis in some location that lacks strong motion records.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.580-585
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• 2000

Recently TEIS model, Two-zone model aid Stanitz equations are often used for off-design performance prediction of centrifugal compressor and pump. The prediction results often agree well with experimental data. However these models and equations have some important variables which have a great influence on overall performance prediction me. But no systematic study about these variables has been performed. So, in this paper, a systematic study about these variables influence on overall performance prediction owe is peformed. Finally the meaning of the variables and the research to be undertaken are discussed.