• New & Renewable Energy
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• v.1 no.1 s.1
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• pp.54-63
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• 2005

A critical issue in the field of the rotor aerodynamics is the treatment of the wake. The wake is of primary importance in determining overall aerodynamic behavior, especially, a wind turbine blade includes the unsteady airloads problem. In this study, the wake generated by blades are depicted by a free wake model to analyse unsteady loading on blade and a new free wake model named Finite Vortex Element(FVE hereafter) is devised in order to include a wake-tower interaction. In this new free wake model, blade-wake-tower interaction is described by cutting a vortex filament when the filament collides with a tower. This FVE model is compared with a conventional free wake model and verified by a comparison with NRELand SNU wind tunnel model. A comparison with NREL and SNU data shows validity and effectiveness of devised FVE free wake model and an efficient.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.2 s.140
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• pp.98-104
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• 2005

The mathematical models of hydrodynamic force and moment acting on a ship at low speed range should be established differently from the ones at nominal cruising speed range since a ship moves with large drift angle or rotates in a stationary position. We modified widely used Yoshimura's cross flow model in order to apply the system identification method to estimate parameters in the model. The apparatus and the procedure of free running model test were suggested so that the parameters in the model be estimated. The validity of our proposing modified model and test procedure was confirmed by comparison with the results of simulated model test.

• Journal of Information Technology Applications and Management
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• v.19 no.2
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• pp.117-134
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• 2012

Cluster industries are geographically concentrated and inter-connected by the flow of goods and services, which is stronger than the flow linking them to the rest of the economy. Photonics industries are one of the fastest growing high-tech industries in the world today. Especially, the city of Gwangju(South Korea) industrial cluster, a specialized complex in photonics industry, produced remarkable results in developing high-quality technologies since it launched the cluster program in 2005. Gwangju photonics industrial cluster will be ranked top level of the world photonics industry. In this sense, this study is aimed at proposing a new research model in which corporate performance influence factors of photonics industrial cluster (i.e., business environment, cooperative relationship, and industry-university-research institute partnership) affect absorptive capacity positively, leading to corporate performance eventually. This study developed a research model to explain the Korean photonics industrial cluster effects, and collected 91 survey responses from photonics based company managers in industrial cluster complex. To prove the validity of the proposed research model, PLS analysis is applied with valid 91 questionnaires. By employing PLS technique, the measurement reliability and validity of research variables are tested and the path analysis is conducted to do the hypothesis testing. In brief, the finding of this study suggests that corporate performance influence factors of photonics industrial cluster affect absorptive capacity positively, and corporate performance as well.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.2
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• pp.49-56
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• 2003

The welding deformation of a hull structure in the shipbuilding industry is Inevitable at each assembly stage. The geometric inaccuracy caused by the welding deformation tends to preclude the introduction of automation and mechanization and needs the additional man-hours for the adjusting work at the following assembly stage. To overcome this problem, a distortion control method should be applied. For this purpose, it is necessary to develop an accurateprediction method which can explicitly account for the influence of various factors on the welding deformation. The validity of the prediction method must be also clarified through experiments. This paper is aimed at deriving the simple prediction model for fillet welding deformations. For this purpose, the thermal elasto-plastic analysis varying the welding conditions and plate thickness has been performed. On the basis of numerical results, the formulae for angular distortion and transverse shrinkage have been derived through the regression analysis. Experimental work has been also carried out to clarify the validity of numerical results. It has been found that the numerical results show a good agreement with those of experiments

• YAKHAK HOEJI
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• v.41 no.1
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• pp.38-47
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• 1997

Using a concentric cylinder type, rheometer. the steady shear flow properties of vaseline were measured over the temperature range of 20~70${\circ}$C. In this paper, the shea rate and temperature dependencies of its flow behavior were investigated and the validity of some flow models was examined. In addition, the flow characteristics over a wide temperature range were quantitatively evaluated by calculating the various material parameters. Main findings obtained from this study can be summarized as follows: (1) At relatively lower temperature range, vaseline is a plastic fluid with a yield stress and its flow behavior shows shear-thinning characteristics. (2) As the temperature increases, the value of a yield stress and the degree of shear-thinning become smaller, consequently, the Newtonian flow behavior occurs at a lower shear rate range. (3) At temperature range lower than 45${\circ}$C, the flow behavior shows much stronger temperature dependence, and a larger activation energy is needed for flow. (4) The Herschel-Bulkley model is the most effective one g$^3$ to predict the flow behavior of vaseline having a yield stress. The validity of the Bingham and Casson models becomes more available with increasing temperature. The flow behavior of vaseline at temperature range higher than 45${\circ}$C can be perfectly described by the Newton model.

• International Commerce and Information Review
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• v.10 no.2
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• pp.63-87
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• 2008

This study investigates the relationship between perceived system characteristics of Internet shopping mall and loyalty, and examines how perceived website attractiveness and flow play mediating roles between perceived system characteristics of Internet shopping mall and affective commitment in the context of Internet clothing shopping mall. For these purposes, the author developed a structural model which consists of several variables. In this model, perceived system characteristics of Internet shopping mall that consist of such as familiarity, reputation, uniqueness, positive emotion, self-efficacy, and interactivity were proposed to affect the website attractiveness and flow, and in turn, result in higher affective commitment. Thus, perceived website attractiveness and flow were proposed as core mediating variables between perceived mobile service characteristics and affective commitment. To test unidimensionality and nomological validity of the measures of each construct, the author employed scale refinement procedure. The results of reliability test with Cronbach's, and confirmatory factor analysis warranted unidimensionality of the measures for each construct. In addition, nomological validity of the measures was warranted from the result of correlation analysis.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.805-810
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• 2004

The model is verified thorough simulations and experiments. And then the developed model is applied to a half car model and automobile vibrations are analyzed. The effects of tire design parameters on the automobile vibration energy are investigated. The results from laboratory and field tests confirm the validity of the analytical model. The 17-DOF half-car model is built to analyze the automobile vibration. The characteristics of the nonlinear model for a shock absorber are applied to this model. The results from the present 17-DOF half car model incorporating the analytical tire model with tire design parameters, are compared with a 5-DOF half car model where the tire is modeled with linear springs. The results of the 17-DOF model are closed to experimental results. Using the 17-DOF model, the influences of tire design parameter are considered. According to the results of analyses, the vibrations at seat/body/wheel are predicted by simulation and experiment.

• Journal of Korean Academy of Nursing
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• v.50 no.3
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• pp.487-500
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• 2020

Purpose: This study aimed to evaluate the validity and reliability of the Korean version of Menopause-Specific Quality of Life (MENQOL). Methods: The MENQOL was translated into Korean according to algorithm of linguistic validation process. A total of 308 menopausal women were recruited and assessed using the Korean version of MENQOL (MENQOL-K), the World Health Organization Quality of Life Brief Version (WHOQOL-BREF), and Center for Epidemiological Studies Depression Scale (CES-D-K). In estimating reliability, internal consistency reliability coefficients were calculated. Validity was evaluated through criterion validity and construct validity with confirmatory factor analyses using SPSS 23.0 and AMOS 25.0 software. Results: In item analyses, the "increased facial hair" symptom was excluded because of the low contribution of MENQOL-K. The confirmatory factor analysis supported good fit and reliable scores for MENQOL-K model, and the four-factor structure was validated (χ²=553.28, p<.001, NC=1.84, RMSEA=.05, AGIF=.85, AIC=765.28). The MENQOL-K consists of 28 items in 4 domains, including vasomotor (3 items), psychosocial (7 items), physical (15 items), and sexual subscales (3 items). There was an acceptable criterion validity with moderately significant correlation between MENQOL-K and WHOQOL-BREF. The Cronbach's α for the 4 subsacles ranged from .80 to .93. Conclusion: The MENQOL-K is a valid and reliable scale to measure condition-specific quality of life for perimenopausal and postmenopausal women. It can be used to assess the impact of menopausal symptoms on the quality of life of Korean women in clinical trials.

• Korean Journal of Social Welfare
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• v.67 no.3
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• pp.151-180
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• 2015

This study aimed to develop a scale to measure physical health behaviors among social work clients using general services. The scale items were constructed based on literature review and FGI of social workers. Exploratory factor analysis and confirmative factor analysis affirmed the factor structure of Physical Health Behavior Scale with two sub-scales: Health Promotion Behavior Scale and Health Hindrance Behavior Scale. Promotion Scale had 7 factors and Hindrance Scale had 5 factors. Both sub-scales showed acceptable ranged goodness-of-fit for the model, and internal consistency test proved that the scale was reliable. The analyses of discriminant validity, convergent validity, and concurrent validity resulted significant validation. Based on those results, the developed Physical Health Behavior Scale were proved well-constructed, reliable and valid. The Scale will be utilized for both clients in general to check their own health related behaviors and social workers to adopt as a tool for assessment in order to perform an evidence based practice.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.1064-1081
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• 2014

This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.