• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.703-708
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• 2017

The goal of this study is to evaluate behavior uncertainties of structures by using interval finite element analysis based on interval factor method as a specific non-stochastic tool. The interval finite element method, i.e., interval FEM, is a finite element method that uses interval parameters in situations where it is not possible to get reliable probabilistic characteristics of the structure. The present method solves the uncertainty problems of a 2D solid structure, in which structural characteristics are assumed to be represented as interval parameters. An interval analysis method using interval factors is applied to obtain the solution. Numerical applications verify the intuitive effectiveness of the present method to investigate structural uncertainties such as displacement and stress without the application of probability theory.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.700-703
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• 2003

The test method of ASTM E 756 and KS D 0076 to estimate vibration-damping properties is compared. Comparison method depending on specimen support, exciting method and calculation method for loss factor is used. Half-power bandwidth method and vibration decay method is used in the calculation method for loss factor, and Young's modulus is decided by geometric character and density for specimen and resonance frequency. Vibration measurement sensor is compared by using non-contact displacement detector, velocity detector and accelerometer. This paper is also presented the matter which is able to cause error in the measurement

• Korean Journal of Health Education and Promotion
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• v.18 no.3
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• pp.117-131
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• 2001

This study was attempted to develope a highly reliable and valid tool which is useful to assess the Korean obese adolescents' stress and coping method. The data were collected from the total of 600 obese students from middle and high schools in Pusan. The author used a convenience sampling method. The data collection was done from March 2 to July 11, 1999. The analysis of the data was done with SPSS Win(10.0) for descriptive statistics and factor analysis. The preliminary tool was composed of 72 items(stress items: 34, coping method items: 38) with the five point Likert scale. Item analysis and inter consistency were calculated for reliability and validity through pre-test. The preliminary tool was analyzed for reliability and validity. Finally, the tool was of 65 items(stress items: 33, coping method items: 32). The results were as follows: 1. Cronbach Coefficient Alpha for the 33 items of stress was .9485 and the 32 items of coping method was .8534. 2. The factor analysis was done in order to confirm construction and the items were extracted Oblimin rotation and Maximum likelihood extraction method. 3. The factor analysis showed 6 factors in stress and 10 factors in coping method. These 6 factors of stress explained 62.4％ and 10 factors of coping method explained 57.4％. 4. Six factor of stress lable were 〈outward appearance〉, 〈boyfriend/ girlfriend〉, 〈occur an outbreak of disease〉, 〈mutual relation of family〉, 〈an obese figure〉, 〈be a burden on exercise〉. 5. Ten factor of coping method lable were 〈be concerned about another affairs〉, 〈recreation activities〉, 〈self-violence〉, 〈relaxation〉, 〈hobby activities〉, 〈avoid a situation〉, 〈communication〉, 〈music〉, 〈negative behavior〉, 〈positive thinking〉. The results of using this scale in a study will contribute to design an appropriate school health management of obese students, and also it will contribute to the development of nursing research.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.93-100
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• 2013

This paper propose a method to design the rotor of synchronous reluctance motors(SynRM) for maximum torque and power factor by using DOE(design of experiment) with the design variables which are parameters of barriers and segments. In this process, there are problems that require lots of simulation time and number of simulations when calculating the both torque and power factor using the finite element method in order to find load angle, core loss per speed. In order to improve this problem, we calculate only value of flux linkage by finite element method, and can decrease analysis and the number of analysis time by applying steady state expression of the power factor and torque. Finally, in order to verify the characteristics of optimal model, we make prototype motor and compare with the conventional SynRM. In this experiment, we use the DC current decay test for calculating d-and q-axis inductance.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.6
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• pp.390-395
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• 1987

There is a variety not only of research topics but also of research techniques in electric power problems. It is well known that a significant increase in the rate of convergence can be obtained for the Gauss-Seidel method using the bus admittance matrix by applying acceleration factors determined empirically. The acceleration factor is calculated theoretically by using the bus voltage sensitivity (buses voltage interact each other) in this paper. It is observed that the proposed method using calculated acceleration factor gives better results than those of the method using calculated acceleration factor gives better results than those of the method using empirical one.

• Steel and Composite Structures
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• v.7 no.2
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• pp.119-133
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• 2007

Based on stability theory of current rigid steel frames and using the three-column subassemblage model, the governing equations for determining the effective length factor (${\mu}$-factor) of the columns in semirigid composite frames are derived. The effects of the nonlinear moment-rotation characteristics of beam-to-column connections and composite action of slab are considered. Furthermore, using a two-bay three-storey composite frame with semi-rigid connections as an example, the effects of the non-linear moment-rotation characteristics of connections and load value on the ${\mu}$-factor are numerically studied and the ${\mu}$-factors obtained by the proposed method and Baraket-Chen's method are compared with those obtained by the exact finite element method. It was found that the proposed method has good accuracy and can be used in stability analysis of semi-rigid composite frames.

• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.319-328
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• 2006

A simple approximation method for the stress intensity factor at the tip of the axial semielliptical cracks on the cylindrical vessel is developed. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. For these, 3-D finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The approximation solutions are within $\pm2.5%$ of the those of finite element analysis using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the approximation method provides sufficiently accurate stress intensity factor values for the axial semi-elliptical flaws on the surface of the reactor pressure vessel.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.358-369
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• 2009

In this paper, we propose development of new products including the proposed process of at the customer's requirements. The success of new product development depends on customer satisfaction in the marketplace. Existing product development process, including the customer's interest was weak. In this paper, we propose development of new products which include Kano's attractive quality factor method and Timko's customer satisfaction index factor method. Also we verified new medical treatment of incontinence-nency which is applied to the proposed process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.434-439
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• 2000

In this paper, in order to study the geometric factor effect of a circular hole near a crack tip in a semi-infinite plate, the Dimensionless Stress Intensity Factor, $F(=\frac K {\sigma {\sqrt{\pi a}}})$ is analyzed at the crack tip using a two Dimensional Boundary Element Method (BEM) program which is known as superior in Fracture Mechanics. Kelvin's solution was used as a fundamental solution in BEM analysis and displacement extrapolation method was used to determine Stress Intensity Factor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.359-364
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• 2002

Statistical energy method is widely used for the prediction of vibrational and acoustical behavior of complex structures, such as ship building and automobile in mid-, high frequency ranges. However. in order to convince this SEA result, it is important to verify estimated SEA parameters, e. g. modal density, energy in each subsystem, damping loss factor, coupling loss factor. with possible other method. For modal density parameter, the experimental estimations via Experimental Modal Analysis are checked with those from finite element method for both beam- plate and plate-plate cans. Loss factors are calculated by Lyon's simple method for the two subsystem. finally. modal experiments are carried out by varying the mass added on the junction of two subsystem for the purpose of investigating the influence on the coupling loss factor's behavior.