• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.139-141
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• 2003

The outage cost has very important position for determination of the optimal level or optimal range of reliability in power system expansion planning. Establishing the worth of service reliability is a very difficult and subjective task. This paper addresses the role, need and assessment algorithm and methodology of the outage cost on power system expansion planning. Furthermore outage cost has been assessed using macro approach for our country 15years(1986-2001) in the case study.

• 통상정보연구
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• 제12권4호
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• pp.25-45
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• 2010

The objective of this paper is to review the mechanics of how global e-trade practices can affect a firm's performance. It is well known that the introduction of global e-trade systems can save transaction costs at the macro level. However this study is extended at micro level by determining whether global trade transaction costs influence positively or negatively in exporting firms performances at firm level. A theoretical framework is suggested for determining the usage and performance of global e-trade with the global e-trade barriers. An empirical analysis of South Korean exporting firms has been undertaken. This paper concludes that the global e-trade has yet to overcome the barriers resulting from the transaction costs and asset specificity. In this regard, appropriate action like intensive education and training program should be implemented in order to make South Korea's global e-trade more matured.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• 기독교교육논총
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• 제72권
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• pp.205-223
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• 2022

연구 목적 : 본 연구의 원격 수업환경에서 흥미수준에 대한 자기주도학습 능력의 영향을 문제해결력이 매개하는지 탐색하기 위해서 수행되었다. 연구 내용 및 방법 : 본 연구는 경기도에 위치한 A대학교의 기독교교육과와 유아교육과 학생 64명을 대상으로 했다. 연구를 위해서 흥미수준, 자기주도학습 능력, 문제해결력을 설문을 통해서 자료를 수집했다. 수집된 자료는 SPSS Macro 및 부트스트래핑(bootstrapping)방법을 활용해 흥미수준에 대한 자기주도학습 능력의 영향에 대한 문제해결력의 매개 효과를 분석했다. 그 결과, 흥미수준에 대한 자기주도적학습 능력은 .651 수준에서 정적인 영향이 있는 것으로 나타났으며, 매개변인인 문제해결력을 포함시킨 2단계에서 자기주도학습 능력의 영향이 .543으로 낮아졌으며, 문제해결력의 영향은 .360 수준으로 나타났다. 결론 및 제언 : 이와 같은 결과를 볼 때, 흥미 수준에 대한 자기주도학습 능력의 영향을 문제해결력이 매개하는 것으로 판단할 수 있다. 이와 같은 연구 결과를 통해 원격수업에 있어서 문제해결력 지원을 통해 흥미수준을 향상할 수 있는 시사점을 제시할 수 있다.

• 지역사회간호학회지
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• 제29권1호
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• pp.21-32
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• 2018

Purpose: This study attempted to identify regional disparities of self-rated health among Korean wage workers and to investigate the influencing factors on them. Methods: The study subjects were 25,069 workers in 16 regions who were extracted from the 2014 Korean Working Condition Survey (KWCS). A multilevel analysis was conducted by building hierarchical data at individual and regional level. Results: In this study, 'financial autonomy rate' and 'current smoking rate' were identified as regional factors influencing the workers' self-rated health. When the socio-demographic and occupational factors of the workers were controlled, 'current smoking rate', a health policy factor, explained the regional disparity of workers' health status. Conclusion: We found that the health status of workers can be affected by the health behavior level of the whole population in their residential area. In order to improve the health status of working population and to alleviate their regional health inequalities, it is necessary to strengthen macro and structural level interventions.

• 철학연구
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• 제105권
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• pp.269-290
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• 2008

이 논문에서는 '후향적인 인과관계'를 주장하는 견해들을 크게, 자의적인 행위에 근거한 접근방법, 분석수준별 차이에 근거한 접근방법, 물리방정식에 의한 접근방법, 물리현상에 근거한 접근방법으로 나누어 고찰하고, 그 각각의 특징과 문제점들을 지적했다. 이어서 후향적인 인과성을 펼치는 어떠한 견해도 아직은 설득력 있게 받아들여지지 않고 있음을 밝혔다. 후향적인 인과관계를 펼치는 견해들이 인과성분석에서 주류는 아닐지라도, 상호조건적 동시발생적인 측면에 근거해 대칭적인 관계 속에서 인과관계를 파악하거나, 전체상적인 접근에 의거해 서로가 직접 간접으로 인과관계를 유지하는 것으로 파악할 경우는 어느 정도 논거가 선다. 특히 인과그물이나 전체상적인 측면에서 접근할 경우는 더욱 그렇다. 그러나 유용성이라는 측면에서 본다면, 후향적인 인과성고찰은 원인선행설에 비해 그 설득력이 약하다. 이런 점에서 현재로서는 결과가 원인에 앞서지 못한다는 견해가 주류를 이룰 수밖에 없다.

• Steel and Composite Structures
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• 제39권4호
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• pp.401-417
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• 2021

This study experimentally reveals the influence of welding on grade S690Q high strength steel (HSS) butt joints from both micro and macro levels. Total eight butt joints, taking plate thickness and welding heat input as principal factors, were welded by shielded metal arc welding. In micro level, the microstructure transformations of the coarse grain heat affected zone (CGHAZ), the fine grain heat affected zone (FGHAZ) and the tempering zone occurred during welding were observed under light optical microscopy, and the corresponding mechanical performance of those areas were explored by micro-hardness tests. In macro level, standard tensile tests were conducted to investigate the impacts of welding on tensile behaviour of S690Q HSS butt joints. The test results showed that the main microstructure of S690Q HSS before welding was tempered martensite. After welding, the original microstructure was transformed to granular bainite in the CGHAZ, and to ferrite and cementite in the FGHAZ. For the tempering zone, some temper martensite decomposed to ferrite. The performed micro-hardness tests revealed that an obvious "soft layer" occurred in HAZ, and the HAZ size increased as the heat input increased. However, under the same level of heat input, the HAZ size decreased as the plate thickness increased. Subsequent coupon tensile tests found that all joints eventually failed within the HAZ with reduced tensile strength when compared with the base material. Similar to the size of the HAZ, the reduction of tensile strength increased as the welding heat input increased but decreased as the thickness of the plate increased.

• The Journal of Asian Finance, Economics and Business
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• 제3권1호
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• pp.5-14
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• 2016

This paper investigates announcement effects of the outward foreign direct investment (FDI) projects of the Korean multinational companies. Although the FDI is considered corporate activity that can provide various benefits beyond financial resources, the most previous research focused on macro analysis such as country-level and industry-level analysis instead of the firm-level study, which is required to decide the investment project from a management perspective. Thus, this study examines the relationship between the outward FDI activities of the Korean corporations and their financial performance to fill the gap in this area.

• 한국인구학
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• 제11권1호
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• pp.97-116
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• 1988

This study examines the socioeconomic determinants of fertility behavior in Korea by developing a model which simultaneously takes into account both individual and community-level differences. It especially focuses on the micro-macro nexus of fertility behavior depending on social contexts. This study utilizes micro data obtained from the 1974 Korean National Fertility Survey(KNFS), and macro data obtained from Korean government statistics. The framework of the model is formalized as a set of structural equations modelling the fertility process. The model is formed on a cohort-specific processual basis and is restricted to five-year birth cohorts. Three cohorts of women are studied : those aged 30-34, 35-39, and 40-44. The model includes three fertility-process components : age at first birth, early fertility, and later fertility, which are defined by reference to the age of the mother. The results of this study indicate that socioeconomic development in Korea results in increased age at first birth and reduced numbers of children per couple. In addition to the developmental change, Korea's fertility decline is found to be facilitated by family planning programs. As expected, the effect of family planning on fertility is greater among better-educated women than among poorly educated women. The inconsistent but suggestive result, however, is that the effect of socioeconomic development on fertility is greater among less-privileged women than among more-previleged women.

• 대한산업공학회지
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• 제39권3호
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• pp.198-203
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• 2013

Industry convergence is the inexorable trend, which has become a fundamental concept to understand the industrial dynamics and to develop business strategies. However, most of the previous studies on convergence have dealt with the issues at the macro-level (technology- or industry-level), little attention has been paid to the analysis of convergence at the micro level (firm-level). Recognizing that firms are the principal agents that develop fusion technologies, it is encouraged to help firms to work together for technology convergence. Therefore, this research proposes a collaboration model for SMEs, since SMEs tend to have novel ideas and are flexible enough to make fusion-technology. To do this, we conducted a survey for Korean SMEs and analyzed their successful cases of collaboration, which was used as a basis to develop the model. The research results will help develop strategy or policy to promote the collaboration between SMEs and ultimately to make a fusion-technology.