• 천문학회보
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• 제37권1호
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• pp.67.1-67.1
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• 2012

Shocks are evolved when the relativistic jets in active galactic nuclei (AGNs), black hole binaries, supernova remnants (SNR) and gamma-ray bursts (GRBs) interact with the surrounding medium. The high energy particles are believed to be accelerated by the diffusive shock acceleration and the strong magnetic field is generated by Weibel instability in the shock. When ultrarelativistic electrons with strong magnetic field cool by the synchrotron emission, the radiation is observed in gamma-ray burst and the near-equipartitioned magnetic field in the external shock delays the afterglow emission. In this paper, we performed the 3D particle-in-cell (PIC) simulations to understand the characteristics of these relativistic shock and particle acceleration. Forward and reverse shocks are shaped while the unmagnetized injecting jet interacts with the unmagnetized ambient medium. Both upstream and downstream become thermalized and the particle accelerations are shown in each transition region of the shock structures.

• Journal of Information Technology Applications and Management
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• 제29권4호
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• pp.17-33
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• 2022

This study measures the internal and external competitiveness of 35 OECD countries in the insurance industry. We analyze whether variables related to the Fourth Industrial Revolution affect international competitiveness by applying a nonlinear autoregressive distributed lag model. As a result, the competitiveness of life insurance foreign companies in internal is showing positive responses in high income inequality countries. In addition, insurance companies in countries with low income inequality have shown high performance in external. The non-life insurance industry is less sensitive to shocks than life insurance. This is because non-life insurance is a more dangerous industry than life insurance and there are many restrictions on policies and regulations. The reason is that non-life insurance is a more dangerous industry than life insurance and there are many restrictions on policies and regulations.

• KDI Journal of Economic Policy
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• 제33권2호
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• pp.1-39
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• 2011

본 연구는 거시경제적 변동성(macroeconomic volatility)이 국가마다 다르게 나타나는 현상의 원인을 산업구조적 차원에서 실증분석을 통해 찾아보려는 시도이다. 특히 우리나라 경제에서 서비스산업이 차지하는 역할에 주목하여, 서비스산업이 경기변동성에 미치는 영향을 국내적인 산업구조 측면과 국가 간 비교를 통해 분석하였다. 분석 결과, 우리나라의 경기 변동성은 국가위험도를 중심으로 과거에 비해 크게 개선되었으나 여전히 대내외적 충격의 영향에 노출되어 있으며, 이는 제조업 중심의 산업구조적 특성에 기인한 것으로 판단할 수 있다. 이러한 산업구조하에서는 우리 경제가 대외부문 충격(global sectoral shock)으로 인한 거시경제적 변동에 지속적으로 노출될 수밖에 없다는 것을 의미하며, 구조적으로 나타나는 변동요인을 완화시키기 위해서는 서비스업이 대부분을 차지하고 있는 비교역재 부문이 상대적으로 활성화되어야 함을 시사하고 있다.

• 수산해양교육연구
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• 제20권3호
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• pp.442-451
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• 2008

The purpose of this study is to analyze the impacts of the rapid rise in oil prices on fisheries economy. Even though fishery oils are tax exemption items, such increase in oil prices put a great amount of pressure on Korean fishing operations. Because basically the recent oil shock is externally given, Korean fisheries themselves have little capacity to cope with the disruption of economic environments. The research results turned out that Korean fisheries are extremely vulnerable(or fragile) to external shocks. In this regard, government support issues of oil costs are in the center of debate. It is widely recognized that direct/indirect government financial supports or subsidies would result in economic inefficiency in expense of equity. However, there are second best theories which may justify government intervention into the markets. This second best theory is translated into the constitutional law that instructs the government to protect and promote the primary industries including fisheries, agriculture, and midium/small-scale enterprises. It is apparent that the constitutional law would provide the government with a variety of policy instruments such as more active buy-back programs, tax exemptions and technological development to deal with fisheries economic hardship due to the external pressure such as high oil prices and international fishery orders.

• 한국정밀공학회지
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• 제30권9호
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• pp.977-982
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• 2013

Blades of wind energy plants are exposed to external shocks or internal cracks during operation. Furthermore, the blade surfaces can be contaminated by substances such as dust, blood of birds, salt or insects which can decrease the electricity generation efficiency significantly. For this reason, many blade cleaning companies started to appear and a variety of methods for cleaning were suggested. Despite these diverse methods, there has been no study to investigate how effectively to clean the substances in quantitative manner. In this paper, the cleaning efficiency of two rotor blade cleaning methods, brush and water-jet, is examined through experiments by changing operating parameters. Then, the optimal operating conditions for both methods are derived.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.922-927
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• 1998

Pipe cooling has been popularly used in the mass concreting work to reduce temperature of the structure since it is known to be the easiest way to apply and has been the customary usage. But wrong application of the system results in the harmful effect on the structure by crack formation due to thermal shocks and improper cooling schemes. Thus, this study aims at the suppling of effective cooling methods through parametric study. For this, circulating method, velocity of water supply and circulating duration were selected as critical factors affecting the effectiveness of cooling system. As a results of thermal analysis, it was found that too much thermal gradient in the vicinity of the pipe creates localized radial or circumferential cracks. The duration of circulating cooling may be recommended to be as short as several days which may safely reduce the concrete temperature to below a final stable value. It was also found that pipe cooling is more effective to decrease the degree external restraints than internal one.

• World Technopolis Review
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• 제3권2호
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• pp.66-77
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• 2014

This paper aims at exploring a conceptual framework of analyzing the evolutionary processes of regional economies by reconciling the notion of regional resilience and the concepts prevailing in the disciplines of evolutionary economics and geography. The resilience framework appears to offer a promising outlet with which combination of the seemingly contradictory conceptions is made possible. It can address why some regions manage to adapt to external shocks, renew themselves, or lock out themselves, while others are more locked in decline. In addition, it can also explain how the spatial organization of economic production, distribution, and consumption is transformed over time. Then, regional economic resilience, together with its accompanying vehicle of panarchy, emerges as a workable framework of explaining regional differentiation in regional economic performance and trajectories. Despite the risk of being a fuzzy concept, the resilience conception can be properly operationalized to provide policy principles of regional economic innovation adjusted to region-specific contexts.

• Journal of East-Asian Urban History
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• 제3권1호
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• pp.57-82
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• 2021

This article examines the urban example of Batu Sawar which served as the capital of the Johor kingdom between 1587 and circa 1615. Around the middle of the eighteenth-century European reference works continued to describe Batu Sawar as the capital of Johor, even though the city had long ceased to serve as a trading center, let alone as Johor's capital, and probably no longer existed. Such observations raise the question of urban impermanence-the transience of sizeable settlements with reference to the Malay Archipelago. Two overarching questions form the backbone of the investigation: First, why did Batu Sawar rise as a regional trading center, and second, what are the reasons that contributed to its decline? Batu Sawar's fate was sealed by a combination of factors that included poor defenses, multiple external shocks, destruction by fire, court politics and rivalry between the early colonial powers.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.197-212
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• 2022

The study uses the audited financial statements of 26 Vietnamese commercial banks listed on the Ho Chi Minh City Stock Exchange (HOSE) and Hanoi Stock Exchange (HOSE) during the 2008-2018 period to estimate the system GMM model, which provides empirical evidence on the effect of the variables of customer deposit to total assets (DEPO) ratio, loan to assets (LTA) ratio, liquidity of commercial banks (LIQ), credit development (CRD) ratio, external funding (EFD) ratio, and credit loss provision (LLP) ratio on liquidity risk. The study confirms that commercial banks' internal factors play the most important role, and there is no empirical evidence on macro variables that affect liquidity risk. Finally, in accordance with the theoretical framework, the study uses an estimation method with the R language and the bootstrap methodology to give empirical proof of the nonlinear correlation and U-shaped graph between commercial bank size and liquidity risk. The importance of commercial bank size in absorbing and moderating the effects of liquidity shocks is demonstrated, however, excessive growth in commercial bank size would increase liquidity risk in commercial bank operations.

• East Asian Economic Review
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• 제27권2호
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• pp.115-143
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• 2023

In this paper, we address how the monetary authority should react to financial market status and exchange rate movements in a small open economy New Keynesian model with financial frictions due to asymmetric information between savers and borrowers. We show that the small economy with financial frictions is more susceptible to the exogenous shocks under the fixed exchange rate regime than under the flexible exchange regime. The small economy experiences a more prolonged and deeper economic recession under the fixed exchange rate regime than under the flexible exchange rate regime. The monetary policy taking into account external finance premium is better than the interest rate rule without considering the financial market status.