• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1356-1361
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• 2018

Replacing conventional Si diodes with SiC diodes in Si insulated gate bipolar transistor (IGBT) modules is advantageous as it can reduce power losses significantly. Also, the fast switching nature of the SiC diode will allow Si IGBTs to operate at their full high-switching-speed potential, which at present conventional Si diodes cannot do. In this work, the electrical test results for Si-IGBT/4HSiC-Schottky hybrid substrates (hybrid SiC substrates) are presented. These substrates are built for two voltage ratings, 1.7 kV and 3.3 kV. Comparisons of the 1.7 kV and the 3.3 kV Si-IGBT/Si-diode substrates (Si substrates) at room temperature ($20^{\circ}C$, RT) and high temperature ($H125^{\circ}C$, HT) have shown that the switching losses in hybrid SiC substrates are miniscule as compared to those in Si substrates but necessary steps are required to mitigate the ringing observed in the current waveforms. Also, the effect of design variations on the electrical performance of 1.7 kV, 50 A diodes is reported here. These variations are made in the active and termination regions of the device.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.57-67
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• 2003

Security Policy Model is a structured representation using informal, semiformal or formal method of security policy to be enforced by TOE. It provides TOE to get an assurance to mitigate security flaws resulted from inconsistency between security functional requirements and functional specifications. Therefore, Security Policy Model has been required under an hish evaluation assurance level on an evaluation criteria such as ISO/IEC 15408(Common Criteria, CC). In this paper, we present an evaluation method for security policy model based on assurance requirements for security policy model in Common Criteria through an analysis of concepts, related researches and assurance requirements for security policy model.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.311-331
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• 2021

Climate change with extreme hydrological events has become a significant concern for agricultural water systems. Climate change affects not only irrigation availability but also agricultural water requirement. In response, adaptation strategies with soft and hard options have been considered to mitigate the impacts from climate change. However, their implementation has become progressively challenging and complex due to the interconnected impacts of climate change with socio-economic change in agricultural circumstances, and this can generate more uncertainty and complexity in the adaptive management of the agricultural water systems. This study was carried out for the agricultural water supply system in Seongju dam watershed in Seonju-gun, Gyeongbuk in South Korea. The first step is to identify system disturbances. Climate variation and socio-economic components with historical and forecast data were investigated Then, as the second step, problematic trends of the critical performance were identified for the historical and future climate scenarios. As the third step, a system structure was built with a dynamic hypothesis (causal loop diagram) to understand Seongju water system features and interactions with multiple feedbacks across system components in water, agriculture, and socio-economic sectors related to the case study water system. Then, as the fourth step, a mathematical SD (system dynamics) model was developed based on the dynamic hypothesis, including sub-models related to dam reservoir, irrigation channel, irrigation demand, farming income, and labor force, and the fidelity of the SD model to the Seongju water system was checked.

• Wind and Structures
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• v.32 no.3
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• pp.267-281
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• 2021

Bending-twisting coupling induced in big composite wind turbine blades is one of the passive control mechanisms which is exploited to mitigate loads incurred due to deformation of the blades. In the present study, flutter characteristics of bend-twist coupled blades, designed for load alleviation in wind turbine systems, are investigated by time-domain analysis. For this purpose, a baseline full GFRP blade, a bend-twist coupled full GFRP blade, and a hybrid GFRP and CFRP bend-twist coupled blade is designed for load reduction purpose for a 5 MW wind turbine model that is set up in the wind turbine multi-body dynamic code PHATAS. For the study of flutter characteristics of the blades, an over-speed analysis of the wind turbine system is performed without using any blade control and applying slowly increasing wind velocity. A detailed procedure of obtaining the flutter wind and rotational speeds from the time responses of the rotational speed of the rotor, flapwise and torsional deformation of the blade tip, and angle of attack and lift coefficient of the tip section of the blade is explained. Results show that flutter wind and rotational speeds of bend-twist coupled blades are lower than the flutter wind and rotational speeds of the baseline blade mainly due to the kinematic coupling between the bending and torsional deformation in bend-twist coupled blades.

• Asia-Pacific Journal of Business
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• v.11 no.1
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• pp.77-91
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• 2020

Purpose - The purpose of this study is to examines the effect of corruption pressure in host country on sequential investment. The study further investigates how the information acquisition capacity of MNEs and the political tie in the host country had a moderating effect on the relationship between corruption and sequential investment. Design/methodology/approach - Ordered logistic regression is hired to analyze 1,260 MNEs' sequential investment in Vietnam. Findings - The empirical results of this study demonstrate the more MNEs perceive the strong level of pressure to be corrupt in the local market, the less they are likely to invest. The information acquisition capacity of MNEs has been shown to mitigate the negative effects of corruption pressures on sequential investments, while the moderating effect of political tie in host country is partially supported. Research implications or Originality - This study identified that the corruption pressures of host countries negatively affect not only MNEs that are entering, but also the ones that have already entered host countries; the corruption discourages any sequential investment for existing MNEs. By suggesting two moderating variables, this study will provide managerial implications for MNEs and managers who face corruption pressure in host countries.

• Advances in concrete construction
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• v.11 no.2
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• pp.163-171
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• 2021

This paper studies the effect of using multi-scale reinforcement additives on mechanical strengths, damage performance, microstructure, and water absorption of cementitious composites. Small dosages of carbon nanotubes (CNTs) or polypropylene (PP) microfibers; 0.05%, 0.1%, and 0.2% by weight of cement; were added either separately or simultaneously into cement mortar. The experimental results show the ability of these additives to enhance the mechanical behavior of the mortar. The best improvement in compressive and flexural strengths of cement mortar reaches 28% in the case of adding a combination of 0.1% CNTs and 0.2% PP fibers for compression, and a combination of 0.2% CNTs and 0.2% PP fibers for flexure. Adding CNTs does not change the brittle mode of failure of plain mortar whereas the presence of PP fibers changes it into ductile failure and clearly enhances the fracture energy of the specimens. Scanning electron microscopic (SEM) images of the fracture surfaces highlights the role of CNTs in improving the adhesion between the PP fibers and the hydration products and thus enhance the ability of the fibers to mitigate cracks propagation and to enhance the mechanical performance of the mortar.

• Geomechanics and Engineering
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• v.24 no.3
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• pp.205-213
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• 2021

Water infusion has long been taken as an effective way to eliminate coal burst risk as coal properties can be loosen and soften by water infusion. However, not all industrial trials of water infusion for coal burst prevention have been necessarily effective in all situations as the effectiveness of this method can be affected by water infusion time, coal properties and the parameters of water injection. Hence, some fundamental issues including the effects of water infusion time on burst propensity and energy evolution need to be further discussed. In this paper, four groups of coal specimens with 0 day, 5 days, 10 days, and 15 days water saturation time are tested under uniaxial compression load with the application of AE monitoring. To comprehensively compare the burst behavior of coal specimens under different water saturation time, stress-strain curves, AE counts, fragmentation characteristics and burst propensity of these groups are analyzed. It was found by this research that sufficient water saturation can mitigate the burst behavior of coal samples while insufficient water infusion might cannot reach the burst mitigation aims.

• Journal of the Korea Fashion and Costume Design Association
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• v.22 no.4
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• pp.79-91
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• 2020

This research aims to study the effect of consumer ethnocentrism and animosity towards the purchase of Korean visual arts products by Chinese consumers. Total of 302 questionnaires were distributed for measuring the constructs using the online survey website (www.sojump.com). All the questionnaires were validated and tested for further statistical analysis through exploratory factor analysis (EFA) and later a confirmatory factor analysis (CFA) using SPSS 22.0 and AMOS 22.0 statistical systems. In addition, structural equation modeling technique (SEM) was applied for testing the hypotheses. Among all variables, consumer ethnocentrism plays the most negatively significant role, followed by animosity toward buying Korean products. Fortunately, there is a positive variable, cosmopolitanism, that can help mitigate the impact of this hostility, and more interesting results are described in detail in the current paper. This study has been added value between theory and practice exploring ethnocentrism and animosity effects, and more theoretical and managerial implications are discussed.

• Journal of Home Health Care Nursing
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• v.27 no.3
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• pp.271-283
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• 2020

Purpose: This study aimed to develop a scale measuring the Tae-Wom in nurses. Methods: The initial items were based on an extensive literature review and in-depth interviews with seven nurses with varied careers. Thirty-five items were derived from a pilot survey. Data were collected from 196 hospital nurses, and analyzed to identify items of the scale as well as to verify the exploratory factor analysis, reliability, and validity of the scale. Results: The results of the exploratory factor analysis showed that six factors contained 26 items and 65.2% of the total explained variance. These six factors comprised negative behavior exhibited by the Tae-Wom recipient, personal character of the Tae-Wom giver, personal character of nursing unit managers, work attitude of the Tae-Wom giver, overwhelming workload, and unskilled relationships. Furthermore, convergent and discriminant validity testing verified these items. The internal consistency reliability was acceptable (Cronbach's α= .93), and Cronbach's α for each factor ranged from .62 to .90. Conclusion: The developed Tae-Wom scale will serve as a tool for verifying the Tae-Wom state in nursing organizations. Therefore, this scale is expected to mitigate the negative effects of the Tae-Wom.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1372-1390
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• 2020

An attractive user interface (UI) design with a clear user experience (UX) is the key for the success of applications. Therefore software development projects require very close collaboration between SI developers and front-end service developers. However, methodologies for software development only exist with inadequate development processes or work standards for collaboration. This survey derived 13 risk factors in developing UI/UX from 113 risk factors of IT projects through a questionnaire and factor analysis and proposed a collaboration-based UI/UX development model that can eliminate or mitigate six risks with high weights and reliability. To extract risk factors with high reliability, factor and reliability were analyzed to extract 13 major risks, and based on the expert opinions and the results of correlation analysis, UI/UX development stages were classified into planning, design, and implementation. The causal relationships between risks were verified through regression analysis. This study is the first to expertly analyze major risks based on collaboration in UI/UX development and derive a theoretical basis that can be used in project risk management. These findings are expected to provide a basis for research on development methodologies for higher levels of front-end services and to construct rational collaboration systems between SI practitioners and front-end service providers.