• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.60-67
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• 2018

The presence of induction motor loads in a power system may cause the phenomenon of delayed voltage recovery after the occurrence of a severe fault. A high proportion of induction motor loads in the power system can be a significant influence on the voltage stability of the system. This problem referred to as FIDVR(Fault Induced Delayed Voltage Recovery) is commonly caused by stall of small HVAC unit(Heating, Ventilation, and Air Conditioner) after transmission or distribution system failure. This delayed voltage recovery arises from the dynamic characteristics associated with the kinetic energy of the induction motor load. This paper proposes the UVLS (Under Voltage Load Shedding) control strategy for dealing with FIDVR. UVLS based schemes prevent voltage instability by shedding the load and can help avoid major economic losses due to wide-ranging cascading outages. This paper review recent topic about under voltage load shedding and compare decentralized load shedding scheme with conventional load shedding scheme. The load shedding strategy is applied to an actual system in order to verify the proposed FIDVR mitigation solution. Simulations demonstrate the effectiveness of the proposed method in resolving the problem of delayed voltage recovery in the Korean Power System.

• 한국해양환경ㆍ에너지학회지
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• 제19권2호
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• pp.99-110
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• 2016

해양에서 시추작업 중 라이저가 손상되어 기름유출이 발생하면 경제적인 피해 뿐 아니라 해양환경에 막대한 피해를 가져오게 되므로 사고 발생 시 신속하게 사고에 대처해야 될 뿐만 아니라 초기의 기름 유출량 및 확산 정도를 파악하는 것이 중요하다. 본 연구에서는 소스코드가 공개된 전산유체역학 라이브러리인 OpenFOAM을 이용하여 손상된 라이저로 부터 기름이 유출되는 현상을 해석하였다. 수치방법을 검증하기 위해 제트 유동과 밀도 차에 의한 확산 문제인 Rayleigh-Taylor instability를 해석하였다. 라이저의 손상된 크기, 기름 유출량, 손상된 위치, 해류의 속도를 변화시키며 해석하였다. 해석 결과 기름이 유출 될 경우 수면에 도달 할 때까지 이동한 거리 및 시간을 예측하여 기름 확산에 대비할 수 있는 가이드라인을 제시하였다.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.29-38
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• 2022

The enormous sway of COVID-19 on the international financial market has been felt across the globe. The financial markets of Bangladesh have also been similarly affected by the global epidemic and experienced a significant increase in volatility. To scrutinise the connection between COVID-19 and the Dhaka Stock Exchange (DSE) indices' return and instability, this study uses data of the DSE from February 2014 to September 2021. A comparative examination of the return and instability of the stock indices of the DSE has also been done considering the outbreak of the current COVID-19 situation. After using the GJR-GARCH (1,1) model, this review uncovers that the outbreak of COVID-19 has a statistically positive noteworthy association with the DSE stock indices' instability, which increases the market's volatility. Traders' fear and the rising frequency of COVID-19 reported patients could cause this. Besides, according to this study, COVID-19 shows a substantial positive linkage with stock market returns that increases the market's return. An appealing valuation, lower interest rates in the banking channel, economic rebound following the closure to prevent coronavirus transmission, improved remittance inflows, and a return of export revenues could all have contributed to this outcome. In addition, the findings also reveal that all market indices are in a mean-reverting phase.

• 통상정보연구
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• 제12권3호
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• pp.167-195
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• 2010

The global financial crisis, the instability of the global economy since the beginning of the growing economic interests of the countries to adjust to establish a new economic system was set up on occasion. Meanwhile, standing in the international trade environment, multilateral system of international trade for the country as the cumulative fatigue of open markets and trade liberalization as an alternative to lead the free trade agreements between countries. Currently in Korea and China, in addition to the geographical proximity in all areas, including economic exchanges and mutually dependent relationship that is deepening the world's No. 1 exporter in China and overseas investors have become partners. FTA with China by promoting the growth of emerging economies in the Chinese market by securing a stable economic growth of China as a driver of economic growth in the country to utilize the plan is being promoted from. This study is currently being promoted, in a discussion of the FTA's agricultural trade measures to address the challenges and poems. Agricultural trade with other goods to be different from the specificity of the discussion of market opening and liberalization of trade has been recognized in the main essentially nothing. We promote an FTA, according to one review and discuss the background and trends of the agricultural trade in a market, through the analysis of the status and trends and present problems for future bilateral trade negotiations with Korea for agricultural markets and propose countermeasures for. Agricultural trade, during a discussion of the FTA is essentially nothing in the review is expected to expand the bilateral trade in agricultural products, while protecting its agricultural markets to be trying to policy implications.

• International Journal of Human Ecology
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• 제7권2호
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• pp.53-62
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• 2006

The purpose of this study is to examine the changes in financial structure of the self-employed brought on the economic crisis in Korea.. We use financial ratio analysis, such as income to expenditure ratio, liquidity ratio, debt ratio, and capital accumulation ratio to analyze financial well-being of self-employed households. This study used a 1997 and 1998 Korean Household Panel Study collected by Daewoo Economic Research Institute. The average amount of holding of each type of asset showed that the investment of self-employed households decreased in the banking industry and the stock market in 1998 compared to 1997. On the other hand, asset allocation in bond and real estate increased, which implied preference for a stable type of asset with the increase in uncertainty of the future and economic instability. Devaluation of real estate allowed households to easily obtain real estate and increase preference for asset allocation in real estate after the crisis. The changes in financial ratio for the year 1998 shows that such ratios as income to expenditure, liquidity, and capital accumulation, decreased compared to the year 1997. Among those ratios, the income to expenditure ratio showed the biggest decline because of reduced income of self employed households. The results implied that the income structure of the self-employed is unstable, thus the self-employed were likely to be greatly affected during the economic downturn. Earners have more average income and net assets than the self-employed. However, using financial ratios, it was found that self-employed households were more stable than employees. The results shows that the financial ratio analysis is better tool to estimate households financial status. Implications for financial educators, counselors, and planners are offered. The results will provide implications for policy makers to establish appropriate policies for the self-employed and help them financially survive.

• 한국전자거래학회지
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• 제24권4호
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• pp.109-118
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• 2019

최근 미중 무역 갈등에 따른 주식시장의 불안정성으로 인해 많은 사람들이 비트코인의 투자에 관심을 보이고 있고 다수의 선행연구에서 이를 안전자산에 대한 투자로 해석하고 있다. 그러나 최근의 비트코인 시세 변동 폭이 크다는 점을 감안하면 투기적 매수세로 인한 결과로 해석할 여지도 있어 비트코인의 자산 성격을 어떻게 분류하여야 하는가는 관련 회계정보의 분석에 중요한 기준점이 될 수 있다. 본 연구는 비트코인의 안전자산 여부를 판별하기 위해, 비트코인과 경제 지표들 간의 상관관계를 분석하여 금과 비트코인이 지표들과의 시계열 관계에서 유사하게 반응하는지 검증하였다. 분석 결과는 금과 비트코인의 가격 간의 회귀분석 설명력은 낮아 서로 간의 관련성이 낮음을 보인다. 또한, 최근의 6가지 경제 변수와 그랜저 인과관계 분석 결과 비트코인의 경우 변수들과 인과관계가 성립하지 않았다. 이는 단기간의 급격한 가격 변동이 비트코인 자산 성격에도 상당한 영향을 미치고 있음을 반박하는 결과로 볼 수 있다.

• 한국직업건강간호학회지
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• 제8권2호
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• pp.176-192
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• 1999

The purpose of this study is to analysis change of industrial health and safety before and after economic crisis(1997~1998). The data were obtained through mail interview with health supervisor(occupational health nurses) during February, 1999. The final sample was consisted of 127 respondents, 97 are selected in this study. The major findings were as follows: First, the percent of industries whose empl safe supervisors, physicians and industry hygi decreased in number is 79.4%, 3.8%, 50.0 21.5% in each. Second, man receiving over 1.5 million won as an average wage of health supervisor is 27.5% in 1997, but it decreased to 25.3% in 1998. Man receiving under 100~150 million won is 48.4% in 1997, but this percent decreased to 36.3% in 1998 and 13.6% of health supervisor regularly were transformed to contingent worker in 1998. Third, especially, budgets for health and saf work place decreased to 13.8% in 1998 than 19. Fourth, industrial accident case, unre accident case, occupational disease decreased than 1997, but mortality from industrial a increased in 250%. Fifth, according to the health diagnosis report, number of case with evidence of disease increased in liver disease, tuberculosis and so on, and number of case with evidence of occupational disease increased in noise induced hearing loss, pneumoconiosis. organic solvent poisoning and so on. Sixth, this survey shows that health council, health education in duty of health supervisor was conducted passive in 1998 thin 1997, and percent of hold two or more positions is 47.6% in medical insurance, 10.7% in accountant's business 8.3 in secretory. 7.1% in telephone operator awl 22.6% in etc. Seventh, distress of health supervisor after economic crisis is 30.9% in employment instability, 19.8% in hold two or more positions and decrease of budgets. For subjugation of the trouble, the respond of active policy of government occupied most.

• 자원환경지질
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• 제8권4호
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• pp.211-221
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• 1975

Weathering of granites has a geochemical role of great significance, because of their abundance and because of chemical instability near the surface of the earth, which is more pronounced than in most other rocks. On the other hand the granites are tectonically fragile and "react" to deformation with marked facility, giving rise to a whole gamut of deformed rocks. Therefore, the writer has studied on the weathering of granitic rocks at of Iri city and Jeonju city Jeollabukdo, Korea, The fresh and weathered rocks were used as material for the investigation. The results obtained by chemical analysis and observation are as follows. 1) The order of mobility in major elements was Ca, Na and K$H_2O$ was observed clearly and late stages of weathering processes. 3) The early stage of weathering is commenced by physical weathering and followed by chemical weathering. 4) The ratio of FeO/. $Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3 $ decreased uniformly from early to late stage of weathering processes. 5) It was proved that weathering potential of granite was larger than that of basaltic rocks.

• 기술혁신연구
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• 제7권1호
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• pp.1-13
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• 1999

In this article, we first present an inductive taxonomy of national R&D structures in terms of relative R&D flows among prime actors. The R&D structure of Korea, along with the Japanese one, turns out to be an ill-balanced one characterized by the dominant role of private sector, vis-a-vis the minimal share of public R&D. In nature, private R&D is sensitive to business cycle and the vulnerability of the Korean structure has been invisible under prosperity but now is disclosed under depression. This problem is nothing new and indeed has long been recognized by the Korean government but the prescription seemed almost impossible. Ironically, the current economic crisis of Korea renders an unexpected opportunity for structural reform. As private firms are cutting down R&D investment, the relative share of public sector becomes significant. A simulation predicts that balanced systems will be achieved in some years if public R&D budget is kept up. Although the contraction of private R&D is by no means desirable, it is the right time for the Korean government to expand public R&D. Public R&D should be considered not only a remedy for market-failure but also a shock-absorber against cyclic instability. This is why the balance between public R&D and private R&D is emphasized.

• 한국경영공학회지
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• 제23권4호
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• pp.19-31
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• 2018

Corruption is a serious political factor that distorts economic structure and slows economic development. In particular, the transition to the market opening economy increases the corruption incentives due to the transitional situation. The purpose of this study is to investigate the influencing factors on corruption using 2013 Myanmar Enterprise Survey data provided by World Bank. As a result of the analysis, it was found that the manager's willingness to dealing the regulation and the necessity of licensing had a positive relationship with corruption at the level of 90% and 95%, respectively. In the competitive environment factor, the intensity of the competition showed a significant increase at the level of 90%. In the institutional environment, the perception of social corruption and the obstacle of the taxation authorities increased the corruption. On the other hand, the increase in the instability of the political environment and strict enforcement of laws has been shown to reduce corruption. However, there was no significant relationship between managerial capacity, corruption of competitors, tax rate, and administrative environment.