• Corrosion Science and Technology
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• 제6권1호
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• pp.29-32
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• 2007

The final goal of this study is to develop the core technologies applicable to the design, operation and maintenance of welds in nuclear structures. This study includes predicting microstructure changes and residual stress for welded parts of nuclear power plant components. Furthermore, researches are performed on evaluating fatigue, corrosion, and hydrogen induced cracking and finally constructs systematically integrated evaluation system for structural integrity of nuclear welded structures. In this study, metallurgical and mechanical approaches have been effectively coordinated considering real welding phenomena in the fields of welds properties such as microstructure, composition and residual stress, and in the fields of damage evaluations such as fatigue, corrosion, fatigue crack propagation, and stress corrosion cracking. Evaluation techniques tried in this study can be much economical and effective in that it uses theoretical/semi-empirical but includes many additional parameters that can be introduced in real phenomena such as phase transformation, strength mismatch and residual stress. It is clear that residual stress makes great contribution to fatigue and stress corrosion cracking. Therefore the mitigation techniques have been approached by reducing the residual stress of selected parts resulting in successful conclusions.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.526-539
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• 2015

Stirling engines are regarded as an efficient and promising power system for underwater devices. Currently, many researches on one-dimensional model is used to evaluate thermodynamic performance of Stirling engine, but in which there are still some aspects which cannot be modeled with proper mathematical models such as mechanical loss or auxiliary power. In this paper, a four-cylinder double-acting Stirling engine for Unmanned Underwater Vehicles (UUVs) is discussed. And a one-dimensional model incorporated with empirical equations of mechanical loss and auxiliary power obtained from experiments is derived while referring to the Stirling engine computer model of National Aeronautics and Space Administration (NASA). The P-40 Stirling engine with sufficient testing results from NASA is utilized to validate the accuracy of this one-dimensional model. It shows that the maximum error of output power of theoretical analysis results is less than 18% over testing results, and the maximum error of input power is no more than 9%. Finally, a Stirling engine for UUVs is designed with Schmidt analysis method and the modified one-dimensional model, and the results indicate this designed engine is capable of showing desired output power.

• Strategy21
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• 통권44호
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• pp.103-141
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• 2018

As the South China Sea maritime dispute illustrates, when considering the place where maritime claims occur, states do not have many choices to respond to maritime claims in which disputed areas are located far away from the land and are surrounded by the sea. As Mearsheimer (2014) points out, the sea stops power projection. Therefore, in order to adopt coercive as well as peaceful settlement policies to deal with maritime claims, states need to overcome obstacles (the sea) to project power. It means that if states want to conduct a specific foreign policy action, such as negotiating maritime borderlines or arguing sovereignty on islands, they need a tool (naval power) to coerce or to persuade the opponent. However, there are lack of research that studies maritime claims from the perspective of naval power. This research project fills this gap based on naval power. How do relative levels of naval power and (dis) parities of naval power influence the occurrence of MIDs over maritime claims? Naval power is a constitutive element during maritime claims. If disputants over maritime claims have required naval power to project their capability, it means that they have the capability to apply various ways, such as aggressive options including MIDs, to accomplish their goals. So, I argue that when two claimants have enough naval power to project their capabilities, the likelihood of MIDs over maritime claims increases. Given that one or both states have a certain level of naval power, how does relative naval power between two claimants influence the management of maritime claims? Based on the power transition theory, I argue that when the disparities of relative naval power between claimants becomes distinctive, militarized conflicts surrounding maritime territory are less probable. Based on the ICOW project which codes maritime claims from 1900 to 2001, the empirical results of the Poisson models show if both claimants have projectable naval power, the occurrence of MIDs over maritime claims increases. In addition, the result shows that when disputants maintain similar relative naval powers, they are more likely to initiate MIDs over maritime claims. To put it differently, if naval capabilities' gap between two claimants becomes larger, the probability of the occurrence of MIDs decreases.

• 응용통계연구
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• 제24권6호
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• pp.1197-1211
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• 2011

The actual power performance of historical structural change tests are compared under various alternatives. The tests of interest are F, CUSUM, MOSUM, Moving Estimates and empirical distribution function tests with both recursive and ordinary least-squares residuals. Our comparison of the structural tests involves limiting distributions under the hypothesis, the ability to detect the alternative hypotheses under one or double structural change, and smooth change in parameters. Even though no version is uniformly superior to the other, the knowledge about the properties of those tests and connections between these tests can be used in practical structural change tests and in further research on other change tests.

• 기술혁신학회지
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• 제1권2호
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• pp.192-207
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• 1998

This paper focuses on the relationship between innovation and export performance of technology-based firms in Korea. This study analyses the relationship between innovative activity and firm's performances using a sample of 760 technology-based firms in Korea. As for the firm's performance indicators, export is employed. The empirical results support that innovation has a positive effect on firm's export performance. However, for small and medium firms, the relationship between innovative activity and export performance is an U-shape quadratic form, which shows that small firms takes a minimum innovative expenditure in order to access the abroad market. Also, with product differentiation, innovative firms tends to devot more to domestic market than to abroad market. Therefore, it can be concluded that innovative activity builds market power and accelerates export performance. And product differentiation through advertising expenditure make innovative firms less exporting.

• 패션비즈니스
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• 제9권4호
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• pp.44-58
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• 2005

In a global market environment with information technology, the textile and apparel industry tries to survive by having competitive power embedded in Supply Chain Management to improve the interrelation among different stages of industries such as fiber, textile, apparel manufacturing, and retailing. The purpose of this empirical study was to investigate performance on Supply Chain Management of textile firms such as 4 textile export firms and 10 collaborate firms which were adopted SCM system. For research methodology, we developed questionnaires based upon interview and literature review. The results of this study were as follows: There were neutral responses or somewhat dissatisfactions on SCM application from CEOs, CMOs, site workers, and collaborators, but over half of respondents indicated 21-40% improvement of affairs. Standard documents and information sharing of SCM system were salient effects. SCM system with standard documents improved receipts/payments and inventory management most.

• Journal of Information Technology Applications and Management
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• 제19권4호
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• pp.171-184
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• 2012

We suggest that cultural differences among nations should have a significant impact upon the exports of Korean broadcasting contents due to the fact that production and consumption of the contents are influenced by their own cultural aspects. Based on Hofstede's cultural dimensions frequently cited in the literature, we perform empirical analysis to identify the impact of cultural dimensions upon the export amounts by investigating four-year export data of Korean broadcasting industry. In our research model, Hofstede's cultural dimensions and GDP per capita are independent variables and a genre of broadcasting contents is used as a moderating variable. We find in our analysis that three cultural dimensions such as individualism, uncertainty avoidance, masculinity significantly affect the export amount but do not find the impact of power distance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1073-1075
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• 1998

This paper presents the method of parameter estimation of diffusion model for monitoring Demand-Side Management Program. Bass diffusion model was applied in this paper, which has different values according to parameters ; coefficients of innovation, imitation and potential adopters. Though it is very important to estimate three parameter, there are no empirical results in practice. Thus, this paper presents the method of parameter estimation in case of few data with constraints to reduce the possibility of bad estimation. The constraints are empirical results or expert's decision. Case studies show the diffusion curves of high-efficient lighting and also forecasting of the peak value for power demand considering diffusion of high-efficient lighting, the feedback and least-square parameter estimation method used in this paper enable us to evaluate the status and forecasting of the effect of DSM program.

• Communications for Statistical Applications and Methods
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• 제23권3호
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• pp.215-230
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• 2016

The powers of some tests for independence hypothesis against positive (negative) quadrant dependence in generalized Farlie-Gumbel-Morgenstern distribution are compared graphically by simulation. Some of these tests are usual linear rank tests of independence. Two other possible rank tests of independence are locally most powerful rank test and a powerful nonparametric test based on the $Cram{\acute{e}}r-von$ Mises statistic. We also evaluate the empirical power of the class of distribution-free tests proposed by Kochar and Gupta (1987) based on the asymptotic distribution of a U-statistic and the test statistic proposed by $G{\ddot{u}}ven$ and Kotz (2008) in generalized Farlie-Gumbel-Morgenstern distribution. Tests of independence are also compared for sample sizes n = 20, 30, 50, empirically. Finally, we apply two examples to illustrate the results.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.311-324
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• 2018

Herein,the Neodymium ion ($Nd^{3+}$) doped CoAl-LDH have been successfully prepared via co-precipitation method and was used as a precursor of Nd-doped CoAl-mixed metal oxides (MMO). The photocatalytic activity of doped LDH and MMO was investigated in the degradation of an azo dye, C.I. Acid Red 14, under visible light irradiation. DRS and PL analysis demonstrated decreasing in the band gap energy and recombination of photo-induced charge carriers of Nd-doped LDH and MMO compared with the pristine CoAL-LDH. Due to significant difference in photocatalytic performance. A power law empirical kinetic model was obtained for predicting the photocatalytic degradation efficiency.