• Journal of Korea Port Economic Association
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• v.32 no.2
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• pp.59-71
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• 2016

This study empirically examines the dynamic specification of the ship price model based on a vector autoregressive model and data covering from January 2000 to October 2014. Our results are summarized as follows: first, the relationship between ship price and interest rate shows significantly negative and the relationship between ship price and freight rate shows positive. It provides consistent implication that ship price depends on interest rate and freight rate under the dynamic Gordon model. Second, we apply an impulse response analysis to ship price and find the responses of the ship price from both factors, interest rate and freight rate, which affect during seven periods approximately. Finally, the results of a variance decomposition indicate that freight rate is more important than interest rate on the ship price.

• Korean Journal of Remote Sensing
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• v.24 no.6
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• pp.571-581
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• 2008

The sea fog occurs frequently in the west coast of Korea in spring and summer. This study focused on the detection of sea fog using MODIS satellite images. We presented a method for sea fog detection based on the homogeneity level between low stratus and sea fog, which was that the top surface of sea fog had a homogeneous aspect while that of low stratus had a heterogenous aspect. The results showed that the both homogeneity of $11{\mu}m$ brightness temperature (BT) and brightness temperature difference (BTD, $BT_{3.7{\mu}m}-BT_{11{\mu}m}$) were available to discriminate sea fog from low stratus. The frequency of difference between BT in fog/stratus area and BT in clear area provided reasonable result. In addition, the threshold values of standard deviations of BT and BTD in the fog/stratus area were applicable to differentiate fog from low stratus.

• Journal of the Korean Institute of Educational Facilities
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• v.28 no.1
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• pp.15-23
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• 2021

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.216-227
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• 2007

The aim of this paper is to find out the nature of causality between the two ocean freights employing the Granger method. That is because the Baltic freights tend to move very closely and seem to be behave like one time series. The Granger causality test, however, is very sensitive to the number of lags used in the analysis. This means that one has to be very careful in implementing the Granger causality test. This paper, hence, uses more rather than the lags which the Akaike Information Criterion and the Schwarz Information Criterion suggest. This study shows that BPI does not "Granger-cause" BCI and BSI, but BCI and BSI Granger-cause BPI. I also discover that BHSI does not "Granger-cause" BPI and BSI, but BPI and BSI Granger-cause BHSI. I, hence, model and estimate the ocean freight function and show that the Baltic ocean freight market is inefficient and the biased estimator of the other freight.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.1
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• pp.111-123
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• 2022

In the era of the Covid19, container shipping rates are surging up. Many studies have attempted to investigate the factors affecting a surge in container shipping rates. However, there is limited literature using text mining techniques for analyzing the underlying causes of the surge. This study aims to identify the factors behind the unprecedented surge in shipping rates using network text analysis and LDA topic modeling. For the analysis, we collected the data and keywords from articles in Lloyd's List during past two years(2020-2021). The results of the text analysis showed that the current surge is mainly due to "US-China trade war", "rising blanking sailings", "port congestion", "container shortage", and "unexpected events such as the Suez canal blockage".

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1998.10a
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• pp.26-26
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• 1998

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.142-143
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• 1998

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.11a
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• pp.41-42
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• 1998

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.565-578
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• 1997

Clouds are usually formed by adiabatic cooling through ascending currents, radiation cooling or a mixture of warm air and cold one. Ascending currents are caused by covection currents, or they are accompanied with fronts. Thus clouds are formed through various kinds of causes and procedures. So they are various in height and shape. Form of clouds was classified on the basis of the thecriteria that L. Howard proposed in 1803. He distinguished three simple, fundamental classes-Cirrus, Cumulus, Stratus-from which the others were derived by trasition or association. And they are subdivided into 10 genera according to their height and shape. Most of the clouds are subdivided into the detailed kinds to the characteristics such as appearance or intensity of convection current. Sometimes completly different shape of cloud can be developed out of the 'mother-cloud'. In korea, the stratocumulus, altostratus and cirrus clouds frequently appear. Generally we are likely to have rain or snow from the stratus cloud forms(As, St, Sc) and rain shower or hail from the cumulus forms(Ac, Cu, Cb).

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.23-29
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• 2018

Contrail is type of clouds which are formed by a condensation of water vapour from the aircraft exhaust when the aircraft is flying the cold atmosphere. Since contrails have considerable effect on greenhouse-effect and military stealth efficiency, researches about contrail avoidance technology has been conducted for decades. However, none of the previous researches concerning contrail avoidance was carried out in Korea. Thus, review of the previous study regarding contrail reduction is absolutely needed. In this paper, researches conducted by several countries are categorically introduced, and practicabilities of their methods are analyzed. This paper also suggests some practical and systematized way to conduct future researches about contrail avoidance.