• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.43-47
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• 2002

Weight loss experiments have been performed for unidirectional carbon fiber/epoxy laminates under both isothermal and cyclic thermal conditions. It was found that weight losses were the result of both specimen-geometry dependent oxidative degradation and volumetric geometry dependent thermal degradation. Thermal degradation was found to play a major role in the overall weight loss process, and photomicrographs of cross-sectioned, aged specimens confirmed this fact. A method to predict the effect of isothermal environment on the weight loss was introduced and found to be in good agreement with experimental data at temperatures near Tg (glass transition temperature).

• Journal of Photoscience
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• v.8 no.3_4
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• pp.119-121
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• 2001

Three-Dimensional Quantitative Structure-Activity Relationship(QSAR) has been investigated over 67 flavonoids to correlate and predict GI$\sub$50/ values. The partial least-squares(PLS) model was performed to calculate the activity of each derivatives, and this was compared with the actual value. The results of the cross-validated(${\gamma}$$^2$=0.997) values show that cytotoxic activities play an important role which is in good agreement with the observed GI$\sub$50/ values.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.27-27
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• 2017

The rapid growth of world population, reduction of cultivated areas for crop production, and detrimental effects of pests, diseases, and climate changes have required to breed new rice cultivars with high yield, accepted quality, but strong resistance to abiotic and biotic stresses. However, traditional breeding needs much time to breed a new cultivar, whereas the successful use of molecular breeding is still questionable. We have developed a novel mutation which allow to cross many rice cultivars together with low segregation, that allow to breed a new cultivar in only several cropping. The mechanism has been unknown, but we suggest that gene linkage may play a crucial role, of which the semi dwarf gene might be the center gene for gene linkage occurrence. The phenomenon of this possible gene linkage is contrary to Mendel rules, but it is promising to breed new rice cultivars, of which, the most elite genes in rice might be able to gather in a targeted rice variety.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.317-324
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• 2001

This study deals with high power Nd:YAG laser welding of thin steels for small pressure vessels. Full penetration welding at the overlap joint was performed so as to assure sufficient weld strength. Results showed that mid-depth weld size reduced drastically with increasing the travel speed. Position of focus had little effect on the bead formation even though short focal system was used. However, the shape factor and the bead width had closely related with the position of focus. Based on the microstructural inspection, acceptable weld was obtained when the overlap clearance was controlled up to 20% of the base metal thickness. In the case that the joint contained more clearance than the critical value, both the tensile shear strength and the tear strength were reduced. Results also demonstrated that shielding gases were proved to play a key role as far as the bead formation characteristics was taken into consideration. Blowing dry air through 5mm in diameter nozzle produced narrower bead cross-section than that of argon or nitrogen shielding.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.185-185
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• 2001

The CD95 (Fas, APO-1) is known to play a key role as a transmembrane cell surface receptor that mediates apoptosis of many cell types through binding with Fas ligand or cross-linking to agonistic anti-Fas antibody. Activation of CD95 provokes a potent and rapid responses in a variety of cell types by unknown mechanism.(omitted)

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.3
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• pp.141-147
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• 2005

In the field of electrical industry, embedded computing environment including hardware and software is getting more important as the industry shifts to the knowledge-based one. Java could play a great role as bridging technology in such a transition because it provides a lot of benefits like dynamic application download, compatibility of cross platform, and its own security solution. However, the Java technology has a limitation of real-time problem when it is applied to the embedded computing system of the electrical industry. To solve the problem, a novel java-native combination model has been proposed and designed to a firmware level. This scheme has been employed in four kinds of control boards. The result shows that the proposed model has great potential to implement the real-time processing in control of the devices.

• Management & Information Systems Review
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• v.26
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• pp.1-26
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• 2008

Since Capital Asset Pricing Model(CAPM) was proposed in the early 1960s by William Sharpe(1964) and John Lintner(1965) researchers have investigated the validity of the model. The results of empirical researches do not show that expected returns of stocks seem to be determined solely by systematic risk of the stocks as precicted by CAPM. In this paper the relationship between transaction volume and expected returns of stocks was investigated. Empirical cross-sectional analysis about the data collected from Stock Market of Korea Exchange shows transaction volume and variability of stock returns play an important role in pricing assets. The well-known variables which were used traditionally to explain the differences of expected returns among stocks such as the size and beta of a stock seems to be unimportant in pricing assets.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.73-97
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• 2009

The IT implementation literature suggests that various implementation factors play critical roles in the success of an information system; however, there is little empirical research about the implementation of data warehousing systems has unique characteristics that may impact the importance of factors that apply to it. In this study, a cross-sectional survey investigated a model of data warehousing success. Data warehousing managers and data suppliers from 51 organizations completed paired mail questionnaires on implementation factors and the success of the warehouse. The purpose of this study is to identify which factors have a positive impact on the successful implementation of DW among organizational implementation success, project implementation success, and technical implementation success which are selected as implementation factors of DW. To do so, this study comprehensively analyze the previous studies on the success factors of the information system and DW to develop the study model and set the hypothesized. Then, it verified the hypothesis via the empirical analysis after collecting the materials through the survey. Finally, the discussion of the study's results, offered the implications of the findings, and the conclusions of the findings followed.

• Asian Journal for Public Opinion Research
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• v.7 no.1
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• pp.1-22
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• 2019

In the age of continuous media change and the coexistence of multiple forms of media, the relationship between the public's media use and political participation is an urgent area of study. This paper makes use of large national sample surveys from 2002, 2011, and 2015, summarizes the change of the public's media use by descriptive statistics analysis, and finds that while the Internet has become an important communication channel, the use of Internet for political information and political participation is still overestimated. Compared to the weak impact of different media channels for political information on political participation, the frequency of media exposure and Internet use play a significant role in political participation. Because of the negative effect of the frequency of Internet use on political participation, the democratization function of the Internet needs to be treated with caution. This paper describes media use and its roles in contemporary China, analyzes the impact of media use on political participation, and extends the cross-cultural application of the theory of political communication.

• Journal of Korean Port Research
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• v.8 no.1
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• pp.31-40
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• 1994

Experimental study is carried out to verify the advantages of an air chamber structure in controlling the wave transformation and its dynamic responses. The open, cross and vertical mooring systems are employed in experiments to investigate the variations of wave transmission ratio, natural period of the structures and tensile force acting on the mooring line according to the change of the initial air depth inside the air chamber structure. Experimental results show that the air chamber floating structure expresses the smaller wave transmission ratio and tensile force acting on the mooring line than general one without air chamber, expecially in the long period region of incident wave. Therefore, it is concluded that the air chamber structure suggested in this study can play good roles as a wave controlling castal structure, and a substitute structure of a general floating structure.