• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.335-340
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• 2005

This thesis tries to evaluate the economic benefit of space chartering in comparison with time chartering with respect to mega container ships. For this it reviews the method of obtaining ship's carrying capacity such as time chartering and space chartering. Based on this, it tries to make comparison between the time chartering and space chartering on economic base. Finally, it suggest the economic benefit of space chartering with direction for further study.

• Journal of the Korean Institute of Navigation
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• v.20 no.2
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• pp.59-76
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• 1996

We have implemented the questionnaire survey to study the structure of consciousness of collegian and the Change of the worth view of the vocation on totally 832 collegians who attended to fisheries and martime colleges. The results were as follows : Most collegian had selected college and department by means of surrounding recommendation and acquired scores without regarding his own aptitude and prospect. The educational aims of the collegian who majored in fisheries and maritime field are to carry out the theory and practise along with emphasizing technical education and human-being education together. Concerning to the status of professor. Most collegian had wanted professor not only who had much comprehensive faculty but also who pointed out than well teaching professor. The collegian who consult their prospect with professor was very rare and they were very negative for the learning majoring in fisheries and maritime field. Because the practice guidance was not accomplished effectively on the account of social aspect, most collegian has avoided jobs relating to fisheries and maritime field. Also, they had selected short term on the job training couse aboard the ship.

• Journal of Welding and Joining
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• v.30 no.4
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• pp.38-43
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• 2012

Using a fiber laser heat source, an oil pressure sensor was fabricated to measure the pressure in commercial vehicles. A stepping motor was used for the rotational and translational motion in the diaphragms and hardware joining. Laser welding process algorism including shielding gas control and vision system was integrated by using LabVIEW software for the high quality welding and in-line monitoring purpose. For the maximum flexibility in pressure transmission to the pressure sensor, thin sheet metal diaphragm, $25{\sim}50{\mu}m$(SUS-316L), was used and the diaphragms were optimally designed with FEM analysis. The welded samples were cross-sectioned the observation showed that the maximum depth ratio was more than seven times of diaphragms. The maximum welding speed was measured to be as high as 50in/mm by the developed automation mechanism. The fabricated prototypes were tested for the proof pressure, spring constant and sealing. The FEM results of spring constant measurement was as accurate as up to 80% of the design value and the sensor was safely operated up to the nominal pressure of 10bars.

• Economic and Environmental Geology
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• v.18 no.2
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• pp.167-175
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• 1985

Geothermal heat flow distribution of Korea is investigated in the light of geophysical data, seismicity, tectonics and gravity as well as heat flow measurements and surface temperature of hot springs. The average heat flow in Korea is found to be $1.65{\mu}cal/cm^2{\cdot}sec$ that is greater than the world's average ($1.5{\mu}cal/cm^2{\cdot}sec$). The high heat flow is located at the regions of high seismicity in Korea. They are found to be Bugok of south central, and Haeundae, Pohang and Dongnae of the southest coast in the Peninsula. The anomalously high heat flow, equal to or greater than $1.93{\mu}cal/cm^2sec$ is found in the Kyongsang Basin, indicating that it is extended from the spreading of the East Sea (Japan Sea) and its origin.

• Journal of Welding and Joining
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• v.34 no.4
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• pp.23-27
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• 2016

A 3D printed metal part and thermal plastic polymer part were joined by direct laser irradiation. The 3D metal part was fabricated by using DED(Direct Energy Deposition) with STS316 material. The experiment was carried out through no patterned metal surface, 3D metal printed surface and micro laser patterned surface. The most secure joining quality was obtained at the laser micro patterned surface specimen and the counterparts of polymers were PLA and PE based thermo plastics. The applied laser power was 350Watt and the distance of patterns was maintained at $150{\mu}m$. The laser line width was optimized at $450{\mu}m$ and the laser micro pattern depth was $180{\mu}m$ for the best joining quality. Based on the result analysis, the possibility of laser material joining for metal to polymer was proposed and multi-material joining will be possible in 3D laser direct material fabrication.

• Journal of Welding and Joining
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• v.28 no.3
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• pp.42-48
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• 2010

Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) were welded by a combination of a diode laser and a CNC machining center. Laser beam delivered through the transparent PC and was absorbed in an opaque ABS. Polymers were melted and joined by absorbed and conducted heat. Experiments were carried out by varying working distance from 44mm to 50mm for the focus spot diameter control, laser input power from 10W to 25W, and scanning speed from 100 to 400mm/min. The weld bead and cross-section were analyzed for weld quality, and tensile results were presented through the joint force measurement. With focus distance at 48mm, laser power with 20W, and welding speed at 300mm/min, experimental results showed the best welding quality which bead size was measured to be 3.75mm. The shear strength at the given condition was $22.8N/mm^2$. Considering tensile strength of ABS is $43N/mm^2$, shear strength was sufficient to hold two materials. A single process was possible in a CNC machining system, surface processing, hole machining and welding. As a result, the process cycle time was reduced to 25%. Compared to a typical process, specimens were fabricated in a single process, with high precision.

• Journal of Korea Port Economic Association
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• v.34 no.3
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• pp.183-200
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• 2018

This study empirically tests the presence of rational bubbles in the ship prices using time series data from October 1996 to April 2017. To detect the existence of ship prices' rational bubbles, we use integration and cointegration tests, which were proposed by Campbell and Shiller(1987) and Diba and Grossman(1988), for circumventing misspecification of ship price model and applying the bubble test to nonstationary time series. The result of integration test supports existence of tanker price's rational bubble. The co-integration test also shows that drybulk ship and containership prices have been overvalued relative to the market fundamental, drybulk and container freight rates, due to non-stationary rational bubbles. These results provide Korean shipping industry and authorities implications that anticyclical ship investment and long-term and steady fleet capacity expansion policy are needed.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.684-694
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• 2011

The purpose of this study is to provide the basics of effective Fisheries and Merchant Marine High School education by analyzing Fisheries and Merchant Marine High School students' perceptions about their educational environment and school education. To achieve the purpose of this research, the study carried out a survey targeting 350 Fisheries and Merchant Marine High School students. The findings are as follows: First, the perceptions about instructions of department is generally positive. And they demand expansion of practice instruction. Second, the perceptions about curriculum is generally positive. And they demand field-experience learning. Third, the perceptions about school management and administration is generally positive. But they dissatisfied with considering their opinion about school management and administration. Fourth, the perceptions about counselling and personality guidance is generally positive. And the efforts to stop school violence are valued most positive. But the satisfaction in club activities is relatively low, so we need to come up with measure to increase club activities.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.3
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• pp.99-118
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• 2023

Objectives : The purpose of this review is to investigate the effect of herbal medicine treatment on cytokines and symptom improvement in patients with psoriasis. Methods : We searched four web databases for studies on psoriasis treated with herbal medicines published from 2000 to April 2023. After searching for studies, we analyzed selected studies based on inclusion criteria. Results : Seven randomized controlled trials have been found and analyzed. All of research which selected have reported that herbal medicine treatment for psoriasis patients have an effect on cytokines and was effective in improving symptoms, and all were statistically significant. Conclusions : According to the results, herbal medicine treatment can be an effective treatment for improving symptoms and cytokines in patients with psoriasis. This study will be helpful for future research in herbal medicine.

• Maritime Security
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• v.6 no.1
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• pp.57-81
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• 2023

This study aims to review Russia's annexation of Crimea from a maritime security perspective. Based on a comprehensive analysis of Russia's national security perception, this study analyzed Russia's maritime security strategy and the security importance of the Black Sea and the Sea of Azov, and reviewed the annexation of Crimea from a maritime security perspective. The main argument of this study is as follows. Russia's annexation of Crimea was necessary for the successful fulfillment of Russia's maritime security strategy in the Black and Azov Seas. Russia's annexation of Crimea guarantees the activities of the Black Sea Fleet militarily from a maritime security point of view, secures a passage to the Atlantic Ocean to counter NATO's expansion. From a economic security point of view, Russia's annexation of Crimea was based on the strategic considerations to secure influence within the Black Sea economic bloc which guarantees stable production and transportation of natural resources and shipping.