• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.6
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• pp.254-261
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• 2003

This study investigates magnetic circuit design of the Single-phase Line-start Permanent Magnet Synchronous Motor (LSPM) to develop the characteristics in steady state. In this paper, the saliency ratio, that is the ratio of q-axial inductance to d-axial inductance, and the inductance difference between q-axial inductance and d-axial inductance are increased. Design factor is selected permanent magnet position and rotor diameter. The analysis method of the synchronous motor on d-/q- axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Back-emf and d-q- axial inductance is analyzed by using 2 dimensional Finite Element Method (FEM). Characteristic analysis results with variation of design factor are reflected magnetic circuit design of LSPM. The characteristics of design model are compared with the characteristic of initial model.

• The KSFM Journal of Fluid Machinery
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• v.16 no.5
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• pp.29-35
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• 2013

Butterfly valve seated rubber has been widely used in water works and industrial fields because it has advantages which are small installation area and low weight. The size and material of butterfly valve have been selected by service environments and purposes. But there are out of the ordinary to find papers for the life characteristics of the butterfly valve. So, this study carries out the accelerated life test, which has an acceleration factor with pressure, using performance and life test equipment. Accelerated model is adopted with 3 stress level and the inverse power law model to estimate the life of the test samples. After the analysis of the test result, accelerated index has 7.0 and the acceleration factor has 208 which is applied with field condition with the pressure 6.3 bar.

• Korean Journal of Occupational Health Nursing
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• v.29 no.3
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• pp.173-183
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• 2020

Purpose: The purpose of this study was to identify factors associated with the mental health-related quality of life (MHQoL) of Korean workers. Methods: This was a cross-sectional study of 192 Korean pay workers who worked in the Daegu and Gyeongbuk Province, Korea. Data were collected from May 15 to July 2, 2019, through selfreported questionnaires. The survey had a total of 87 questions including individual, organizational, and psychosocial factors. MHQoL was measured using short form-36 version 1. Data were divided into four domains of MHQoL and analyzed using a hierarchical linear regression model. Results: From the hierarchical linear regression analysis, when the psychosocial factors were included in the regression model, the R² change in the four domains of MHQoL increased significantly by 19~47%. A common predicting factor associated with the four domains of MHQoL was identified as perceived stress symptoms. Other factors affecting MHQoL showed slight differences in each domain. Conclusion: Based on the study results, it is necessary to monitor the psychosocial symptoms to improve MHQoL of Korean workers. Considering each factor affecting the four areas of MHQoL, workplace-based interventions to improve MHQoL should be provided to workers.

• Journal of Korean Association for Spatial Structures
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• v.13 no.1
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• pp.87-96
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• 2013

This study investigated characteristics of buckling load and effective buckling length by member rigidity of dome-typed space frame which was sensitive to initial conditions. A critical point and a buckling load were computed by analyzing the eigenvalues and determinants of the tangential stiffness matrix. The hexagonal pyramid model and star dome were selected for the case study in order to examine the nodal buckling and member buckling in accordance with member rigidity. From the numerical results, an effective buckling length factor of adopted models was bigger than that of Euler buckling for the case of fixed boundary. These numerical models indicated that the influence of nodal buckling was greater than that of member buckling as member rigidity was higher. Besides, there was a tendency that the bifurcation appeared on the equilibrium path before limit point in the member buckling model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2421-2428
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• 2002

In this study, the failure probability of the degraded LP turbine blade steel was performed using the Monte Carlo simulation to apply variation of applied stress and strength. For this purpose, applied stress under the service condition of steady state was obtained by theoretical stress analysis and the maximum Von-Mises stress was 219MPa. The fatigue strength under rotating-bending load was evaluated by the staircase method. Furthermore, 3-parameter Weibull distribution was found to be most appropriate among assumed distributions when the probabilistic distributions of tensile and fatigue strength were determined by the proposed analysis. The failure probability with various loading conditions was derived from the strength-stress interference model and the characteristic factor of safety was also estimated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.29-35
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• 2013

The pitch reducer consists of several planetary gearsets, and they should have good load distribution over gear tooth flank and load sharing among the planets to improve the durability. This work investigates how bearing internal clearances influence both the load distribution over the gear tooth flank and the planet load sharing. A whole system model is developed to analyze a pitch reducer. The model includes non-linear mesh stiffness of gears, non-linear stiffness of bearings. The results indicate that the face load factor and mesh load factor decrease, and the fatigue life of output shaft bearings increase as bearing internal clearances of output shaft decrease. Therefore, the internal clearance of output shaft bearing must be considered when designing the pitch reducer for wind turbines.

• Journal of Internet Computing and Services
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• v.9 no.3
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• pp.159-167
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• 2008

The purpose of this study is finding factors affecting the students' use of the Cyber Home Learning Service System and exploring the direction of this system. It is based on the TAM(Technology Acceptance Model) and the result of the previous studies, six external and three internal factors influencing the sue of Cyber Home Learning Service System were extracted. The participants were 201 elementary school students in Pusan. The response of the questionnaire was gathered by online survey system. To analyze the data and the hypothesis, multiple regression and factor analysis were explored. The result indicated that (a) "usefulness" and "future-intention" affected statically to the use, (b) "usefulness" to the future-intention, (c) "subjective judgement", "fun", and "ease of use" to the usefulness, (d) "self-efficiency" and "contents quality" to the ease of use.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.8 s.101
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• pp.945-953
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• 2005

The purpose of this paper is to develop a linear regression model for the sound quality index of vehicle Interior noise. For this, objective measurement data of the vehicles driving in acceleration was measured. On the basis of analysis, psychoacoustic parameters were extracted and subjective evaluation was performed by noise and vibration expert evaluators. For the subjective evaluation, the paired comparisons and the semantic differential methods were used to evaluate sound quality of vehicle interior noise. By the paired comparison which evaluate two pairs of vehicle interior noise, the preference was estimated. With the semantic differential and the factor analysis, it was evaluated words of two pairs which expressed appropriately the sense of evaluator about noise source. Therefore the characteristics of the sound qualify for the vehicle were differentiated. From the results of both the correlation analysis and the multiple factor regression analysis, the sound quality evaluation model for the sense of human hearing was derived and indexed.

• International Journal of Quality Innovation
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• v.9 no.2
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• pp.39-56
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• 2008

Six Sigma has been one of main quality improvement approaches since Motorola first invented Six Sigma in 1987. Many scholars and consult experts have discussed the critical success factors of implementing Six Sigma management, but most of them are based on related theories or qualitative analyses. In the paper, we first review critical success factor of Six Sigma status quo based on literature. Then we design the questionnaire and survey China manufacturing enterprises that have introduced Six Sigma management. And finally, we analyze the critical success factors of China manufacturing industry implementing Six Sigma management by using structural equation model and find that leadership and Six Sigma strategy, focus on market and customer, evaluation and motivation, selecting, managing and implementing Six Sigma projects are four critical success factors of China manufacturing enterprises implementing Six Sigma management. At the same time, the paper also presents the relationships between the critical success factors. The results are of important role in China manufacturing industry locating resources, eliminating waste and improving Six Sigma performance.

• Korean Institute of Interior Design Journal
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• v.20 no.2
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• pp.20-29
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• 2011

This research is based on the environmental psychology model of Albert Mehrabian & JAMES a. Russell. The purpose of this research is to search a method of planning a spatial image improving the degree of access that is audience's dependent response to a display space image of a museum for children. A museum for children is the place for education with experience and its main audience is children and parents. It indicates with a basis of the environmental psychology model that a designer needs to consider the emotional response of children and parents in designing the space. The space design starts from a plan of space image that is delivered to audience through the five senses. Image on the space means visual image as people acquire information mostly through the sense of sight. Visual image consists of shape, the feel of a material, and color that is the most influential factor to the sensibility of audience. Therefore, firstly, this research measures the degree of audience's approach and avoidence on image of display space. In addition, this research suggests the improvement method by analyzing differences on the access of each space and audience based on visual image. Secondly, four factors are extracted through factor analysis based on the result of adjective survey result.