• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.884-889
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• 2003

Based on the reinterpretation of the well-known relationship between shear and the rate of change of bending moment in a reinforced concrete beam subject to combined shear and moment loads, the shortcomings of present truss models are discussed. The core of the theory is that a new perspective on the shear strength can be gained by viewing the internal stress filed in terms of the superposition of two base components of shear resistance; arch action and beam action. The arch action can be designed using the simple truss having curved compression chord, while the beam action between the two chords can be modeled using a parallel chord truss with MCFT or RA-STM. The compatibility of deformation associated to the two action is taken into account by employing a characteristic factor a. The new model was examined by the Stuttgart beam shear tests, and the results show that the present approach provides good estimates of stirrup contribution and concrete contributions.

• Journal of Korean Society of Forest Science
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• v.80 no.1
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• pp.20-31
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• 1991

To improve the understanding and predicting power of littering behavior in natural recreation areas, a model was proposed based on the theory of reasoned action by Fishbein and Ajzen. Among the visitors of Kaeryongsan National Park in Korea, three hundred and ninety nine (399) groups were interviewed to obtain such data as beliefs about the behavioral consequences, attitudes, normative belief, socioeconomic status and etc. A significant but practically weak relationship was found between beliefs, normative belief and past behavior (R=0.3). Using Logit analysis, past behavior could be explained with relevant variables in an acceptable power ($R^2$=0.35). In the model, education, social group, occupation, age and visiting frequency were all negatively related to past behabavior. Beliefs and normative belief also behaved as expected by the theory. The study results show that the theory may be useful in predicting the undesirable behaviors in recreation areas and establishing management policy to control them. The cause of weak relationships between relevant variables were discussed and future research implications were also suggested.

• Knowledge Management Research
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• v.17 no.4
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• pp.129-145
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• 2016

Nowadays, owing to the diffusion of smartphones and the growth of social networking services (SNS), the number of people who share their life with other SNS users by posting photos is increasing. The number of Instagram users has been particularly increasing since Instagram started its service in 2010. Compared to other SNS such as Facebook and Twitter, Instagram runs its service by focusing solely on photos, which is a major differentiation factor compared with other existing SNS. Previous studies, however, do not examine SNS that focus on photo sharing adequately. Therefore, we establish a hypothesis relating to the motivations behind a user's photo sharing attitude and posting intention through Instagram. Moreover, this will be achieved by employing TRA(Theory of Reasoned Action) and focusing on intrinsic and extrinsic motivations. The analysis results show that intrinsic motivation influences a user's sharing attitude and subjective norms. Apart from this, Instagram's expressivity influences a user's photo sharing attitude and posting intention.

• Natural Product Sciences
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• v.5 no.4
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• pp.186-189
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• 1999

To analyze scientifically the fundamental formulation theory and drug interaction on the purgative action of Chungpesagan-tang, which is one of the traditional Korean medical prescriptions that has been most frequently used for stroke, water extracts of herbal medicines with Rhei Rhizoma were administered into mice and the purgative action was measured. Water extracts of Raphani Semen or Cimicifugae Rhizoma with Rhei Rhizoma had more potent purgative activity than Rhei Rhizoma alone, although Raphani Semen alone displayed no purgative action. However, Platycodi Radix and Puerariae Radix inhibited the purgative action of Rhei Rhizoma. When Rhei Rhizoma with Raphani Semen or Cimicifugae Radix was extracted with water, sennoside A content in the water extract was increased. However, Puerariae Radix and Platycodi Radix decreased the content of sennoside A in the extracted water. The transforming rate of sennoside A of Rhei Rhizoma was inhibited by Puerariae Radix and Platycodi Radix. The transforming rate of sennoside A of Chungpesagan-tang to rheinan-throne by human intestinal microflora and its purgative activity were similar to those of Rhei Rhizoma. Finally we thought that the purgative action of Chungpesagan-tang could be controlled by the addition and subtraction of Chungpesagan-tang-composing herbal medicines.

• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.343-354
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• 2022

An understanding of the mechanism of concrete girders repaired with CFRP plates and its influence on the dynamic parameters is presented in this paper. Dynamic parameters are governed by the relationship with the physical properties of concrete girders and CFRP plates as well as the adhesive layer between them. A brief explanation of the mechanism of the composite action of concrete girders repaired with CFRP is also given in this paper. Experimental work was carried out to validate the theory of the composite action. The results show a decrease in the modal parameters of CFRP repaired girders that were turned over during the repair procedure, which contrasts with the proven static-based results that CFRP plates increase the stiffness of repaired girders. The composite action theory has explained the results based on the tension and compression forces' growth at the adhesive layer between the CFRP plates and girder surface during the repair procedure. Other girders were prepared and repaired without turning over in order to avoid tension and compression forces at the adhesive layer. The experimental results show an increase in the dynamic parameters of CFRP repaired girders that were not turned over during the repair procedure, which aligns with the static-based results. The study concludes that the dynamic parameters are excellent indicators for the assessment of CFRP repaired concrete girders. The study also suggests that researchers should not turn over damaged concrete girders to repair them with CFRP plates if they intend to study the dynamic parameters, in order to avoid the proposed composite action effect on modal parameters.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.2
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• pp.145-152
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• 2009

In this paper, dynamic instability of plane membrane structures under wind action has been studied. The key to solving the governing equations of membrane structures under wind action is how to obtain the air pressure on membrane. Based on Bernoulli's theorem, fluid pressure has a certain relationship with velocity potential. Velocity potential could be solved according to thin aerofoil theory, where air around the membrane is regarded as a sheet of vortices. In this paper, we take advantage of the most commonly used three-node triangular membrane element and weighted residual-Galerkin method to obtain the determining equation for stability evaluation. Square and rectangular membrane structures are studied. The influence of initial prestressing force and wind direction towards critical wind velocity are also analyzed in this paper.

• Computers and Concrete
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• v.12 no.1
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• pp.19-36
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• 2013

In the finite element analysis of reinforced concrete structures, discrete representation of the steel reinforcing bars is considered advantageous over smeared representation because of the more realistic modelling of their bond-slip behaviour. However, there is up to now limited research on how to simulate the dowel action of discrete reinforcing bars, which is an important component of shear transfer in cracked concrete structures. Herein, a numerical model for the dowel action of discrete reinforcing bars is developed. It features derivation of the dowel stiffness based on the beam-on-elastic-foundation theory and direct assemblage of the dowel stiffness matrix into the stiffness matrices of adjoining concrete elements. The dowel action model is incorporated in a nonlinear finite element program based on secant stiffness formulation and application to deep beams tested by others demonstrates that the incorporation of dowel action can improve the accuracy of the finite element analysis.

• Journal of National Security and Military Science
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• s.2
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• pp.1-21
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• 2004

Clausewitz’s theory of war can be divided between the theory of conduct of war and the theory of preparations for war, and the theory of war that Clausewitz means, is the theory of conduct of war. But before Clausewitz, men regarded a theory of preparations for war as the theory of war. The theory of preparations for war concerns generally about the material side of war, but not its spiritual aspect. The activity of war is basically a human spiritual and psychological action. And because the war is dangerous, the anxiety occurs and diverse human feelings, for example courage, have been required. Also the informations in war is normally very uncertain, so an insight of the commander is in war very needed. The Theory of war has to consider this spiritual aspect. To end the war and to acquire the peace, an excellent talent of commander is necessary. And it is a genius. Men who are difficult to move but have strong feelings, these are the men who are best able to be a genius.

• Nutrition Research and Practice
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• v.11 no.4
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• pp.340-346
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• 2017

BACKGROUND/OBJECTIVES: Despite the importance of consuming sufficient amounts of vegetables, daily vegetable intake among adolescents in Korea is lower than the current dietary recommendation. The objective of this study was to examine determinants affecting vegetable preference in order to suggest a stage-tailored education strategy that can promote vegetable consumption in adolescents. SUBJECTS/METHODS: Adolescents (n = 400, aged 16-17 years) from two high schools participated in a cross-sectional study. Survey variables were vegetable preference, the social cognitive theory (SCT) and stages of change (SOC) constructs. Based on vegetable preference, subjects were classified into two groups: a low-preference group (LPG) and a high-preference group (HPG). SOC was subdivided into pre-action and action/maintenance stages. To compare SCT components and SOC related to vegetable preference, chi-squared and t-tests, along with stepwise multiple-regression analysis, were applied. RESULTS: In the LPG, a similar number of subjects were classified into each stage. Significant differences in self-efficacy, affective attitudes, and vegetable accessibility at home and school were detected among the stages. Subjects in the HPG were mainly at the maintenance stage (81%), and there were significant differences among the stages regarding self-efficacy, affective attitudes, and parenting practice. In the predictions of vegetable preference, self-efficacy and parenting practice had a significant effect in the "pre-action" stage. In the action/maintenance stage, outcome expectation, affective attitudes, and vegetable accessibility at school had significant predictive value. In predicting the vegetable preference for all subjects, 42.8% of the predictive variance was accounted for by affective attitudes, self-efficacy, and vegetable accessibility at school. CONCLUSION: The study revealed that different determinants affect adolescent vegetable preference in each stage. Self-efficacy and affective attitudes are important determinants affecting vegetable preference. Additionally, school-based nutrition intervention that focuses on enhancing affective attitudes, self-efficacy, and vegetable exposure may constitute an effective education strategy for promoting vegetable consumption among adolescents.

• Management & Information Systems Review
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• v.21
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• pp.131-154
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• 2007

The purpose of this study is to understand a information technology acceptance model and to test empirically using field survey. In order to achieve this purpose, first of all, I examined literature reviews about the theory of reasoned action(TRA), the theory of planned behavior(TPB), and the theories of technology acceptance model(TAM). Based on literature reviews, I proposed a technology acceptance model and empirically verified it through using field survey. As a result of, this study was designed to predict and to explain the factors of affecting reuses of a website. The data that were surveyed 193 users of internet were analyzed with SPSS 12.0 and AMOS 4.0. The major results of this study as follows : First, the perceived complexity is influenced by the skill & experience and the quality of system. Second, the quality of system affects the perceived usefulness. Third, the perceived complexity affects the perceived usefulness and the perceived playfulness. Fourth, reuses of a web site are influenced by the perceived usefulness and the perceived playfulness. Finally, the quality of system affects the perceived usefulness and the skill & experience affect the perceived playfulness.