• The Korean Journal of Financial Studies
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• v.11 no.1
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• pp.101-132
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• 2005

증권시장 유동성 문제에 대해서는 학계뿐만 아니라, 투자자, 감독기관 및 시장관계자들의 관심도 크다. 최근의 금융 위기는 금융시장의 유동성이 급격히 감소할 경우 경제적으로 막대한 비용을 치르게 될 수 있음을 일깨워주고 있다. 국내에서도 증권시장의 유동성에 관한 연구는 발표되고 있으나 외국인 투자 행태가 증권시장 유동성에 큰 영향을 미칠 것임을 널리 인식하고 있음에도 불구하고 외국인 투자자와 우리나라 증권시장의 유동성에 어떠한 영향을 미치는지에 대한 체계적인 연구는 드문 실정이다. 따라서 본 연구에서는 유동성 개념에 내포된 시장의 깊이(depth), 시장의 폭(breadth), 가격탄력성(resiliency) 등을 반영하는 다양한 유동성 지표를 설정하고 Panel-VAR 모형에 근거한 충격반응함수를 이용하여 외국인투자행태가 이들 지표에 미치는 영향의 동학적 특성을 분석하였다. 실증분석 결과에 의하면 외국인투자 증가는 주식시장 유동성에 영향을 미치고 있음을 외국인 투자 비중이 높은 주식들 그룹과 이와 유사한 특성을 가진 주식들 그룹의 비교를 통해서 확인할 수 있었다.

• Polymer(Korea)
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• v.31 no.5
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• pp.399-403
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• 2007

Trans-esterification behavior of polycarbonate/poly(butylene terephthalate) (PC/PBT) blends was investigated during the melt mixing process. Rheological and fracture behaviors, and fracture morphology were also investigated as a function of PC/PBT blend ratio. Based on FT-IR and $^1H-NMR$ results, a trans-esterification reaction was confirmed to occur between PC and PBT during the melt mixing process. The melt index(MI) decreased with increased PC content, indicating the higher flow resistance of PC. The storage and loss moduli were increased by increasing the PC loading, and the PC/PBT blends were rheologically incompatible based on the Cole-Cole plot. The tensile property increased linearly with the increased PC content. However, the impact strength increased until 50 wt% of PC loading, notably around $30{\sim}40wt%$, and then was levelled off at 50 wt%. Rough ridges were formed on the impact fracture surfaces above the 40 wt% of PC content, supporting the observed higher impact strength in this range.

• Journal of Korea Port Economic Association
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• v.28 no.3
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• pp.111-125
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• 2012

This study investigates the behavioral characteristic difference of the container volumes of three ports-Gwangyang, Incheon, and Pyeongtaek-Dangjin. All series span the period January 2003 to December 2011. I first test whether the series are stationary or not. I can reject the null hypothesis of a unit root in each of the level variables and of a unit root for the residuals from the cointegration at the 5 percent significance level. I hitherto make use of error-correction model and find that Gwangyang port is the slowest in adjusting the short-run disequilibrium, whereas the adjustment speed of Incheon is much faster than that of Gwangyang. The impulse response functions indicate that container volumes increase only a little to the negative shocks in exchange rate, while they respond positively to the shocks in the business activity in a great magnitude and decay very slowly to its pre-shock level. meaning that the shocks last very long. The accumulative response to the exchange rate increase of 20 won per dollar and the 5 point industrial production increase is the smallest in Gwangyang, no more than a half of that of two ports. The intervention-ARIMA models also forecast that Gwangyang port will have much lower growth rate than Incheon and Pyeongtaek-Dangjin port in trading volumes.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.266-273
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• 2007

Heat shock proteins (HSPs) are a family of highly conserved proteins playing an important role in the functioning of unstressed and stressed cells. The HSP70 family, the most widely studied of the hsps, is constitutively expressed (hsc70) in unstressed cells and is also induced in response to stressors (hsp70), especially those affecting the protein machinery. The HSP/HSC70 proteins act as molecular chaperones and are crucial for protein functioning, including folding, intracellular localization, regulation, secretion, and protein degradation. Here, we report the identification and characterization of the putative amino acid sequence deduced from one cDNA clone identified as heat shock protein 70. The alignment showed that the putative sequence is 100% identical to the heat shock protein 70 cognate (HSC 70) of olive flounder. The 5'-flanking region sequence (approximately 1 kb) ahead of the hsc70 gene was cloned by genome walking and a putative core promoter region and transcription elements were identified. We characterized the promoter of the olive flounder hsc70 gene by examining the ability of 5'-upstream fragments to drive expression of green fluorescent protein (GFP) in live embryos.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.141-149
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• 2017

Due to the inaccuracy of micro-machining, various special processing methods have been investigated recently. Among them, pulse electrochemical machining is a promising machining method with the advantage of no residual stress and thermal deformation. Because the cross section of the wire electrode used in this study is circular, wire-pulse electrochemical machining is suitable for micro-hole machining. By applying the response surface methodology, the experimental plan was made of three factors and three levels: machining time, duty factor, and voltage. The regression equation was obtained through experiments. Then, by referring to the main effect diagram, we fixed the duty factor and machining time with little relevance, and solved the equation for the target 900 microns to obtain the voltage value. The results obtained from the response surface methodology were approximately those of the target value when the actual experiment was carried out. Therefore, it is concluded that the optimal conditions for hole processing can be obtained by the response surface methodology.

• Polymer(Korea)
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• v.24 no.6
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• pp.770-776
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• 2000

The effect of unreactive coupling agent on mechanical and thermal properties of talc-filled polypropylene (PP) composites was studied. Stearic and oleic acids were introduced as coupling agents, and tensile, flexural, and impact strength, thermal stability and melting transition temperature were measured and analyzed according to the types and concentration of coupling agents. Tensile and flexural strength were enhanced by introduction of coupling agent and the maximum effect was observed at the concentration of 3 wt% of coupling agent. Tensile and flexural strength of PP treated with oleic acid were higher than those of PP treated with stearic acid. but impact strength vice-versa. The reasons for these results were postulated by analyzing morphologies of talc-filled PP observed by SEM.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.75-82
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• 2003

The cellular responses of RDX-degrading bacterium, Pseudomonas sp. HK-6 to explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were examined. Strain HK-6 grown at different RDX concentrations was found to demonstrate the survival rate in proportional to the rate of the stress shock proteins produced in this bacterium. Analysis of total cellular fatty acid acids showed that lipids 10:0 iso and 14:1 $\omega$5c/$\omega$5t increased approx three times in strain HK-6 grown on RDX media than TSA media. SDS-PAGE and Western blot using anti-DnaK and GroEL revealed that several stress shock proteins including 70 kDa DnaK and 60 kDa CroEL were newly synthesized in strain HK-6 exposed to different RDX concentrations in exponentially growing cultures. 2-D PAGE of soluble protein fractions from the culture of HK-6 exposed to RDX demonstrated that approximately 300 spots were observed on the silver stained gel ranging from pH 3 to pH 10. As a result, 10 spots were significantly induced and expressed in response to RDX. Scanning electron microscopy fur the cells treated with 0.135 mM RDX for 12 hrs showed the presence of perforations and irregular rod shapes with wrinkled surfaces.

• Environmental and Resource Economics Review
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• v.27 no.1
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• pp.67-104
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• 2018

In this paper, we compare the spread effects of the carbon tax imposition method using the real business cycle model considering the productivity and energy price shocks. Scenario 1 sets the carbon tax rate that encourages the representative firm to maintain a constant $CO_2$ reduction ratio in accordance with its green house gas reduction targets for each period. Scenario 2 sets the method of imposing the steady state value of the carbon tax rate of Scenario 1 during the analysis period. The impulse response analysis shows that the responses of $CO_2$ emissions to external shocks are relatively sensitive in scenario 2. And simulation results show that the cost of $CO_2$ abatement is more volatile in scenario 1, and $CO_2$ emissions and $CO_2$ stock are more volatile in scenario 2. In particular, the percentage changes in volatility between the two scenarios of $CO_2$ emissions and $CO_2$ stock increase as the green house gas reduction target is harder. When the green house gas reduction target is 60% and over, the percentage changes(absolute value) between the two scenarios exceed the percentage change(absolute value) of the $CO_2$ reduction cost between them.

• Journal of Service Research and Studies
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• v.5 no.1
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• pp.91-103
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• 2015

We examine the information transmission between the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index, based on the returns data offered by the Korea Exchange. The data includes daily return data from 1 January 2012 to 31 December 2014. Utilizing a dynamic analytical tool-the VAR model, Granger Causality test, Impulse Response Function and Variance Decomposition have been implemented. The results of the analysis are as follows. Firstly, results of Granger Causality test suggests the existence of mutual causality the KT Futures Index and the SK Telecom Futures Index precede and have explanatory power the KT Spot and the SK Telecom Spot However the results also identified a greater causality and explanatory power of the KT Spot and the SK Telecom Spot over the KT Futures Index and the SK Telecom Futures Index. Secondly, the results of impulse response function suggest that the KT Futures Index show immediate response to the KT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Also the SKT Futures Index show immediate response to the SKT Spot and are influenced by till time 4. From time 2, the impact gradually disappears. Lastly, the variance decomposition analysis shows that the changes of return of the KT Spot and SKT Spot are dependent on those of the KT Futures Index and the SK Telecom Futures Index. This implies that returns on the KT Spot and SKT Spot have a significant influence over returns on the KT Futures Index and the SK Telecom Futures Index. It contributes to the understanding of market price formation function through analysis of detached the KT Spot and the KT Futures Index, the SK Telecom Spot and the SK Telecom Futures Index.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.3
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• pp.281-298
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• 2022

The COVID-19 pandemic has so far given the world a great shock and fear that cannot be compared to other infectious diseases, and local economies are experiencing a serious economic crisis accordingly. This paper examines the regional characteristics of economic recession and resilience due to the COVID-19 pandemic, focusing on the employment fluctuations in 85 cities nationwide. Although the overall trend is in line with national employment indicators, there are some differences in the shock response and the recovery of employment in individual cities. The difference between cities is somewhat greater in the resilience of the recovery stage than the resistance, which is the shock-response stage. In terms of resilience, cities in the capital area have relatively good condition compared to cities in the non-capital area. The weak resilience of large cities such as Seoul, which has a high population density, can be explained to be the effect of the COVID-19 pandemic of infectious diseases. Regarding the economic structure of the city, the ratio of service and sales workers, wholesalers and retailers, and food and lodging businesses are analyzed as valid explanatory variables for the resilience of cities.