• 한국전산유체공학회지
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• 제18권1호
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• pp.1-6
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• 2013

Missile and fighter aircraft have been challenged by low restoring nose-down pitching moment at high angle of attach. The consequence of weak nose-down pitching moment can be resulting in a deep stall condition. Especially, the pressure oscillation has a huge effect on noise generation, structure damage, aerodynamic performance and safety, because the flow has strong unsteadiness at high angle of attack. In this paper, the unsteady aerodynamics coefficients were analyzed at high angle of attack up to 50 degrees around two dimensional NACA0012 airfoil. The two dimensional unsteady compressible Navier-Stokes equation with a LES turbulent model was calculated by OHOC (Optimized High-Order Compact) scheme. The flow conditions are Mach number of 0.3 and Reynolds number of $10^5$. The lift, drag, pressure, entropy distribution, etc. are analyzed according to the angle of attack. The results of average lift coefficients are compared with other results according to the angle of attack. From a certain high angle of attack, the strong vortex formed by the leading edge are flowing downstream as like Karman vortex around a circular cylinder. The primary and secondary oscillating frequencies are analyzed by the effects of these unsteady aerodynamic characteristics.

• 유통과학연구
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• 제11권4호
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• pp.13-21
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• 2013

Purpose - The purpose of this research is to find out the relationship between cue utilization and perceived website quality and purchase intention for an online store. To achieve this, we suggest a conceptual model that examines the relationship among product introductions, online communications, online reviews, perceived quality, and online purchase intention. Research design, data, and methodology - This research utilizes SPSS 19.0 and AMOS17.0 to analyze the data. We used factor analysis to shape the structure of the original data and saved the information with multiple dimensions. We then deployed the AMOS software to analyze the model. We performed both factor analysis and structural equation analysis. Results - The findings of this study show that graphic and word descriptions, online chatting, and online reviews have a positive influence on perceived quality. Furthermore, perceived quality has a positive influence on purchase intention. Conclusions - First, detailed product information should be added to influence quality perception. Second, consumers expect a certain level of service while shopping. Simultaneously, online products reviews from consumers deserve attention as they can impact consumer purchase intention.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.403-412
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• 2020

The main purpose of this paper is to explore how green supply chain management (GSCM) and its evaluative factors have affected green supply chain management practice and performance in industrial zone. This study proposes a structural equation model of the relationships among four factors: internal awareness (IA); suppliers' pressure (SP); customers' awareness (CA); and regulations pressure (RP) and their effect on GSCM practice (PA) and GSCM performance (PE). We used a survey questionnaire to elicit perceptions/opinions about GSCM from three level of managers of 322 companies in Bac Ninh Province's industrial zones, Vietnam. PLS-SEM 3.0 software was applied to analyze and verify the gathered data, and the proposed hypothesis model. The results of path analysis show that internal awareness and customers' awareness are positively related to the GSCM practice and GSCM performance. However, suppliers' pressure and regulations pressure just impacted on GSCM practice. As a result, the testing of the relationship between GSCM practice and GSCM performance has been verified and supported. The findings of this study can help manager of companies in industrial zone understand the structure of GSCM, associate with the green supply chain management practice and green supply chain management performance, and be successful in green management organizations.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.96-104
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• 2006

In the present paper, the effects of combustion instability on flow structure and flame dynamic with the configurations of burner exit in a model gas turbine combustor are investigated using large eddy simulation(LES). A G-equation flamelet model is employed to simulate the unsteady flame behavior. As a result of mean flow field, the change of divergent half angle(${\alpha}$) at burner exit results in variations in the size and shape of the central toroidal recirculation(CTRZ) as well as flame length by changing corner recirculation zone(CRZ). The case of ${\alpha}=45^{\circ}$ show smaller size and upstream location of CTRZ than that of $90^{\circ}$ and $30^{\circ}$ by the development of higher swirl velocity. The flame length in the case of ${\alpha}=45^{\circ}$ is the most shortest, while that in the case of ${\alpha}=30^{\circ}$ is the longest by the decrease of effective reactive area with the absence of CRZ. Through the analysis of pressure fluctuation, it is identified that the case of ${\alpha}=45^{\circ}$ shows the most largest damping effect of pressure oscillation in all configurations and brings in the noise reduction of 2.97dB, comparing with that of ${\alpha}=30^{\circ}$ having the largest pressure oscillation. These reasons are discussed in detail through the analysis of unsteady phenomena about recirculation zone and flame surface. Finally the effects of flame-acoustic interaction are evaluated using local Rayleigh parameter.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.557-562
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• 2004

A surface-piercing barrier model is presented for understanding morphological development in the sheltered region and investigating the main factors causing the severe accumulation. Surface-piercing structures like vertical barriers, surface docks and floating breakwaters are recently favored from the point of view of a marine scenario since they do not in general partition the natural sea. The numerical solutions are compared with experimental data on wave profiles and morphological change rates within a rectangular harbor of a constant depth protected by surface-piercing thin breakwaters as a simplified problem. Our numerical study involves several modules: 1) wave dynamics analyzed by a plane-wave approximation, 2) suspended sediment transport combined with sediment erosion-deposition model, and 3) concurrent morphological changes. Scattering waves are solved by using a plane wave method without inclusion of evanescent modes. Evanescent modes are only considered in predicting the reflection ratio against the vertical barrier and energy losses due to vortex shedding from the lower edge of plate are taken into account. A new relationship to relate the near-bed concentration to the depth-mean concentration is presented by analyzing the vertical structure of concentration. The numerical solutions were also compared with experimental data on morphological changes within a rectangular harbor of constant water depth. Through the numerical experiments, the vortex-induced flow appears to be not ignorable in predicting the morphological changes although the immersion depth of a plate is not deep.

• 한국자동차공학회논문집
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• 제24권6호
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• pp.702-708
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• 2016

The torque converter is deformed according to the rotating speed and control pressure when engine power is transferred to the transmission. This deformation, which is called ballooning phenomenon, occurs mainly at the outer side by the centrifugal force of the automatic transmission fluid (ATF) and the control pressure from the valve body. Although the torque converter is slightly deformed when rotating, the ballooning phenomenon affects fluid performance, efficiency and durability. Thus, expansion characteristics analysis is important in determining torus size, control pressure and structure. In this paper, an analysis equation and FEM model was developed to investigate the expansion characteristics. Using this model, structural analysis was performed to investigate the relationships between deformation and the torus diameter. The results were confirmed by comparing with the test results.

• 패션비즈니스
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• 제15권3호
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• pp.142-155
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• 2011

By developing attitude transfer model, this study examined the co-marketing alliance effect between fashion and other industries (i.e., service and product brands) based upon the information integration theory. In addition, it examined the product tangibility/intangibility effects of partner brands by controlling stimuli: two alliance cases of fashion and service brands and two alliance cases of fashion and product brands. A total of 1,037 Korean women aged 20 to 39 were surveyed to compare the prior- and post- attitudes toward fashion/partner brands under four fictitious co-marketing alliance cases. Confirmatory factor analysis (CFA), multi-group CFA, structural equation modeling (SEM) analysis, and multi-group SEM analysis were conducted to test the hypotheses. The results demonstrated that the prior-attitude toward fashion brand partially affected the alliance attitude, and the co-marketing alliance was affected by prior-attitudes partner brands. The result of multi-group SEM analysis supported the significant differences between service and product brands as alliance partners, which might refer to the effect of product tangibility, existing in brand alliance contexts. The alliance evaluation affected the subsequent evaluations on each participating brands. This study empirically provides the conceptual structure of how consumer attitudes toward the participating brands interact with the attitudes toward alliance and offer practical insights. Specifically, upon employing the manipulated co-marketing alliances cases, this study demonstrates the partnering effect according to product tangibility of partner brands.

• Structural Engineering and Mechanics
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• 제15권6호
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• pp.669-683
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• 2003

The stochastic optimal nonlinear control of coupled adjacent building structures is studied based on the stochastic dynamical programming principle and the stochastic averaging method. The coupled structures with control devices under random seismic excitation are first condensed to form a reduced-order structural model for the control analysis. The stochastic averaging method is applied to the reduced model to yield stochastic differential equations for structural modal energies as controlled diffusion processes. Then a dynamical programming equation for the energy processes is established based on the stochastic dynamical programming principle, and solved to determine the optimal nonlinear control law. The seismic response mitigation of the coupled structures is achieved through the structural energy control and the dimension of the optimal control problem is reduced. The seismic excitation spectrum is taken into account according to the stochastic dynamical programming principle. Finally, the nonlinear controlled structural response is predicted by using the stochastic averaging method and compared with the uncontrolled structural response to evaluate the control efficacy. Numerical results are given to demonstrate the response mitigation capabilities of the proposed stochastic optimal control method for coupled adjacent building structures.

• 디지털융복합연구
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• 제7권3호
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• pp.123-135
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• 2009

The considerable progress of IT industry has changed the industrial structure and lifestyle of our society. One of the remarkable fields of IT industry is online game industry. It showed rapid growth for the past decade. But in recent years online game industry faced with the limit of its growth for a number of reasons. To overcome such situation, online game companies should improve functions of game and analyze their customer's needs for sustainable growth through increasing customer satisfaction and loyalty. The purpose of the study is to investigate and evaluate the factors of online game service quality and the relation of customer satisfaction and loyalty. SPSS 14.0 and AMOS 7.0 are used for experimental research. Through reliability and validity test, service quality factors influencing the customer satisfaction are appeared to be 5 latent variables(reliability, responsiveness, assurance, empathy, tangibles). In addition, by structural equation model and covariance structural model, the result showed that empathy is the most influenced factor to customer satisfaction and customer satisfaction has positive effect on customer loyalty. The results of this research have important implications for explaining an mechanism for service quality of online game, customer satisfaction and loyalty and they might provide operational guidelines to the online game service company.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 춘계학술대회
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• pp.157-179
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• 2008

This study demonstrates some major traits of digital contents as information, playfulness, individuality, perceived recognition as perceived usefulness and perceived ease of use, relationship quality as satisfaction and commitment, user behavior as use intention. To make an empirical analysis the study, it is hypothesized that traits of digital contents and perceived recognition, traits of digital contents and relationship quality, perceived recognition and relationship quality, relationship quality and user behavior. Proposed theoretical model was based on TAM and was tested by the structure equation model for validity, credibility, goodness of fit. The major finding of this study can be summarized as follows, traits of digital contents are positively affected by perceived recognition, satisfaction in relationship quality and use intention via perceived recognition. Theoretical implication of this study are as follows. First, users wanted to choice only needed information. Second, users recognized digital contents as a part of life. So, user's ability is very important in this environment. According to this, business related with or interested in digital contents must have developed digital contents in variety aspect. Users must have concerned using digital contents, also.