• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.1-8
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• 2010

The Fourier series uses a vibrating wave that possesses an amplitude that is like the one of the sine curve. Therefore, the functions used in the Fourier series do not change due to the value of the frequency and that set a limit to express irregular signals with rapid oscillations or with discontinuities in localized regions. However, the wavelet series analysis(WSA) method supplements these limits of the Fourier series by a linear combination of a suitable number of wavelets. By using the wavelet that is focused on time, it is able to give changes to the range in the cycle. Also, this enables to express a signal more efficiently that has singular configuration and that is flowing. The main objective of this study is to propose a scheme called wavelet series analysis for the application of wavelet theory to one-dimensional problems represented by the second-order elliptic equation and to evaluate theperformance of proposed scheme comparing with the finite element analysis. After a through evaluation of different types of wavelets, the HAT wavelet system is chosen as a wavelet function as well as a scaling function. It can be stated that the WSA method is as efficient as the FEA method in the case of axial bars with distributed loads, but the WSA method is more accurate than the FEA method at the singular points and its computation time is less.

• Management & Information Systems Review
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• v.30 no.4
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• pp.117-146
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• 2011

The objective of this study is to investigate factors influencing user's intention to use by expanding TAM(Technology Acceptance Model). Based on this model, this study developed a comprehensive model and user's motivation factors such as extrinsic and intrinsic motivation to describe their intention to accept WCDMA service. For this purpose those who have subscribed to and use the current mobile communication service - all of whom were 13 to 49 years old living in Seoul or other large cities - were surveyed. Structural equation model was conducted to identify and validate the relationship of overall variables relating to mobile service acceptance. The analysis results indicate that intrinsic motivations in mobile service acceptance process have significant impacts on perceived usefulness and perceived ease to use. The results of this study also proposed the way to boost mobile service user's extrinsic and intrinsic motivation for coming up with strategies on how to improve effectiveness of communication and marketing. Future directions and limitations are also discussed.

• Korean Journal of Social Welfare
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• v.63 no.1
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• pp.291-316
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• 2011

The purpose of this study is to find out the right strategies for social welfare education and the efficient human resource management of public social workers. Not to make any flaws when looking for the appropriate strategies, this report studies how outcomes of social welfare education influences the performances of public social workers and how the empowerment is connected to the relationship between the social welfare education and the performances of public social workers. For clearer study, a survey was conducted for 396 public social workers and the Structural Equation Model by AMOS was used to analyze the outcome. According to the result, the Fitness Index of the Casual Model, proposed by this study, was similarly matched with that of theological model. The Casual Model proved that it explains the connection between social welfare education, job performance and empowerment. Hence, to improve performance of public social workers, various education and training policies for human resources management are needed and basically associates related social welfare education should do their effort. Also to enhance empowerment of public social workers, various measures are needed.

• Culinary science and hospitality research
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• v.17 no.5
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• pp.92-107
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• 2011

The purpose of this study was to understand the effect of the characteristics of coupons purchased through a social shopping site upon customer satisfaction and future behavior intention. Based on total 332 samples who had bought franchise restaurant coupons and used them before, this study reviewed reliability and fitness of the research model and verified total 4 hypotheses with AMOS and SPSS program. The hypothesized relationships among the models were tested simultaneously by using a structure equation model(SEM). The proposed model provided an adequate fit to the data, ${\chi}^2$=309.795(df=103, p<.001), CMIN/DF=3.008, RMR=.103, GFI=.912, NFI=.927, CFI=.950, RMSEA=.074. The result showed that the coupon proneness(${\beta}$=.645) and price sensitivity(${\beta}$=-.315) had a significant influence on restaurant satisfaction(p<.001) and only coupon proneness(${\beta}$=1.040) had a significant influence on coupon satisfaction(p<.001). Also, restaurant satisfaction had a positive significant influence on restaurant customers' revisit intention(${\beta}$=.603, p<.001) and coupon users' repurchase intention(${\beta}$=.335, p<.001). Furthermore, coupon satisfaction had a positive significant influence on coupon repurchase intention(${\beta}$=.353, p<.001) but had a negative significant influence on restaurant revisit intention(${\beta}$=-.263, p<.001). Limitations and future research directions were also discussed.

• Culinary science and hospitality research
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• v.16 no.4
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• pp.190-205
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• 2010

The purpose of this study is to understand the effect of physical environment of family restaurant upon customers' emotions, satisfaction and revisit intent. Based on total 438 samples obtained from the empirical research, this study reviewed the reliability and fitness of the research model using Amos program. The hypothesized relationships in the model were tested simultaneously by using a structural equation model (SEM). The proposed model provided an adequate fit to the data, $x^2$ 592.898(p<0.001), df=239, CMIN/DF 2.481, RMR 0.103, GFI 0.900, NFI 0.952, CFI 0.970, RMSEA 0.058. SEM resulted that the physical environment showed a significant effect on customers' positive emotions($\beta$=0.388, p<0.001) and negative emotions($\beta$=-0.148, p<0.001). Also, customers' positive emotion($\beta$=0.828, p<0.001) bad a positive significant effect on customer satisfaction, and customer satisfaction($\beta$=0.771, p<0.001) bad a positive significant effect on revisit intent. Limitations and future research directions are also discussed.

• Journal of the Korean Chemical Society
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• v.10 no.4
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• pp.166-174
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• 1966

The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.1
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• pp.11-23
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• 1997

This paper contains a new approach to blade section design method for marine propellers. The hydrodynamic characteristics of 2-D section are highly influenced by its geometrical parameters i.e., thickness and camber distributions and leading edge radius etc. To consider fully turbulent flow field near 2-D section. the finite volume method with k-${\varepsilon}$ turbulent model which solve Reynolds time averaged Navier-Stokes(RANS) equation is applied. In this study, O-type grid system that can provide many calculation points on blade surface is used. The results were compared with those of the experiment of NACA0012 to confirm the accuracy of the developed codes. The goal of this study is the development of a blade section with high efficiency and low drag. To achieve this, we carried out the tests of lift, drag and cavitation characteristics in cavitation tunnel. The results of experiment were compared with numerical results in order to validate the proposed blades design method. By comparing the numerical results with the experiments, we found that the new blade section, KH28 allows superior performance in efficiency and cavitation avoidance characteristics. We further investigated the blade section design method and an application study of this section, KH28 to apply to the marine propeller. In order to improve the accuracy of numerical results on prediction of lift and drag, we conclude here that the 2-layer boundary model must be used.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.4
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• pp.97-115
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• 2017

The Purpose of this is to Examine the Effects of Collaborative Relations of Supplier- Buyer, Sustainable Supply Chain Management(SCM) Sctivities, and Collaborative Performance in Automobile-part Companies. The Proposed Research Model is Tested using Structural Equation Modeling for Hypotheses based on the Data Collected from 274 Firms. The Results Indicate that Collaborative Relations of Supplier-buyer Positively Affect Sustainable SCM Activities. In Addition, Sustainable SCM Activities Positively Affects Collaborative Performance. The Results of the Study Show that Collaborative Relations of Supplier-buyer is Positively Associated with Sustainable SCM Activities in both Supplier and Buyer Firms. Sustainable SCM Activities have a Significant Impact on Collaborative Performance in both Parts. In Addition, Collaborative Relations of Supplier-buyer have a Significant Impact on Collaborative Performance of Buyer Firms but Supplier. This Study would Provide Useful Information for Collaboration between Supplier and Buyer to have a Long-term Strategic Relationship on Sustainable SCM Activities, which Impact on Collaborative Performance and Competitive Advantages.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.272-279
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• 1988

Kinetics of ascorbic acid destruction and browning were evaluated by the dynamic test using actual drying data in order to apply in the optimization of food dehydration. Radish was chosen as a test material because it has many typical quality characteristics during drying. Radish was dried in the cabinet dryer with being measured in moisture, food temperature, ascorbic acid and browning. Using moisture and temperature history, proposed kinetic model was integrated and parameters of the model were searched by the iteration scheme to show minimum discrepancy between predicted and experimental data. Ascorbic acid destruction and browning were represented by first and zero order reaction respectively. Arrhenius equation was used to describe temperature dependence. Several mathematical functions of moisture dependence were compared in the model simplicity and residual sum of square. Attained kinetic models were analyzed as functions of temperature and moisture. Rate of ascorbic acid destruction was low at high moisture content, increased with moisture decrease to show a maximum at the moisture of $9{\sim}12g/g$ dry solid, and then decreased up to full dryness. Browning rate increased with moisture decrease to show a sharp maximum at $4{\sim}6g/g$ dry solid and decreased with further moisture decrease.

• Journal of the Korean Geotechnical Society
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• v.29 no.2
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• pp.35-45
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• 2013

The void ratio is an important parameter for reflecting the soil behavior including physical property, compressibility, and relative density. The void ratio can be obtained by laboratory test with extracted soil samples. However, the specimen has a possibility to be easily disturbed due to the stress relief when extracting, vibration during transportation, and error in experimental process. Thus, the theoretical equations have been suggested for obtaing the void ratio based on the elastic wave velocities. The objective of this paper is to verify the accuracy of the proposed analytical solution through the error norm. The paper covers the theoretical methods of Wood, Gassmann and Foti. The elastic wave velocity is determined by the Field Velocity Probe in the southern part of Korean Peninsular. And the rest parameters are assumed based on the reference values. The Gassmann method shows the high reliability on determining the void ratio. The error norm is also analyzed as substitution of every parameter. The results show every equation has various characteristics. Thus, this paper may be widely applied for obtaining the void ratio according to the field condition.