• Ocean and Polar Research
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• v.29 no.2
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• pp.123-134
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• 2007

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 km of the coastline using a Smith-McIntyre grab $(0.05\;m^2)$ in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of $1,972\;ind./m^2$, and mean biomass was 82.5 wet-weight $g/m^2$. The major individual-dominant species were three polychaetes Spiophanes bombyx ($436\;ind./m^2$), Scoletoma longifolia ($250\;ind./m^2$) and Magelona japonica ($170\;ind./m^2$), and bivalve Adontorhina subquadrata ($73\;ind./m^2$). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group I contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group I was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (I-I and I-II) in relation to depth. Sub-group I-I was associated with deeper sites than sub-group I-II. Group II included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group II was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.

• Ocean and Polar Research
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• v.30 no.1
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• pp.89-107
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• 2008

Marine environment is subject serious destruction because of frequent accidents during exploration of marine resources and overseas transport. Also, as many industrial enterprises discharge high volume of wastes and contamination, marine pollution has become a serious threat to people (especially in China). China is quickly becoming a world economic leader of the 21st century. Rapid industrialization and social changes have raised the standard of living of millions of the Chinese, mainly in the areas of East and South East coast. The process of industrialization, however, is often followed by deterioration of the marine environment and rarely turned around until a country has increased its standard of living. Solving these array of problems will take decades and currently the government is addressing minor specific issues only. Fortunately, the Chinese government has enacted a number of marine pollution control laws. On 25 December 1999, the 13th Session of the Ninth Standing Commettee of the National People's Congress passed the amended the Marine Environment Protection Law of the People's Republic of China. This Law establishes rights and responsibilities of the relevant departments concerning marine environment management and provides for two new chapters on "Marine Environment Supervision" and "Marine Ecological Protection", along with "Supervision of Pollution Prevention for Marine Construction Projects", "Marine Ecological Protection" and "Marine Environment Pollution Prevention for Marine Construction Projects". Also, the Law was amended with provisions for integrated pollution discharge control system and oil spillage emergency response plan and enhanced legal responsibilities. Chinese government recognizes that international and national experience can be useful for China to prevent further ecological degradation of the marine environment.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.65-70
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• 2009

The hybrid numerical model is developed by combining BEM that can calculate the wave motion rapidly under the potential theory and CADMAS-SURF that solves Navier-Stokes equations for the free surface variation near the structure, In the hybrid model the calculation of wave motion in a wide field of wave reflection for deep water area is conducted by BEM but for shallow water area by CADMAS-SURF. Especially the hybrid model can calculate random wave motions for long term period more rapidly with almost similar accuracy than the calculation of wave motion which was carried out by CADMAS-SURF only. In this study the coupling model was applied to the calculation of the strong nonlinear wave motion such as wave runup and overtopping at the coastal structure on the mild-slope bottom and the results of numerical model were compared with the Toyosima's experiments of regular wave runup and Goda's design diagram of ramdom wave overtopping, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.64-73
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• 2004

During the period of every summer to early autumn seasons, ships have been wrecked or grounded from effect of a typhoon in the waters around Korean Peninsular. Typhoon Rusa killed more than 100 people in September 2002. Super Typhoon Maemi passed southeast of South Korea in September 12-13, 2003, with gale winds blowing at a record 60 m/s and caused much ship groundings, collisions and sinkings over 3000 in dockyards, harbors and places of refuge. These are things that could have been prevented had there merely been prior warning. The aim of this study is to examine what effect these typhoons had on occurrence characteristics of the maritime accidents in South Korea. In this work, records of marine accidents caused by a typhoon are investigated for the period from 1962 to 2002. The distribution is also compared with the trajectories of typhoons, passed during the 1990-2003. It is shown that attack frequency of typhoon and number of marine accidents is the highest in August. We use the track data of Maemi such as central pressure, maximum sustained wind speed and area of each 15m/s and 25m/s winds as a case study to draw a map as a risk index.

• Ocean and Polar Research
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• v.23 no.1
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• pp.51-62
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• 2001

The Arctic consists of numerous sedimentary basins containing voluminous natural resources and two of the world's major oil and gas producing areas. The western Siberia Basin in the Arctic region has the largest petroliferous province with an area of 800 ${\times}$ 1,200 km and produces more than 60% of total Russian oil production. The North Slope of Alaska produces about 20% of the U.S. output, i.e., 11% of the total U.S. consumption. Being small compared to those regions, the Canadian Northwest Territories and the Pechora Basin in Russia produce only fair amount of oil and natural gas. There are also many promising areas in the northern continental shelf of Russia. In addition to Russia, Svalbard and Greenland have been investigated for oil and gas. Gas hydrates are widespread in both permafrost regions and arctic continental shelf areas. The reserves of gas hydrates in the Arctic Ocean are about 20${\sim}$32% of total estimated amounts of gas hydrates in the world ocean. Mineral mining is well developed, especially in Russia. The major centers are located around the Kuznetsk Basin and Noril'sk. They are major suppliers of gold, tin, nickel, copper, platinum, cobalt, iron ore, coal as well as apatite. There are also some minings of lead-zinc in Alaska and Arctic Canada.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.593-597
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• 2005

It is generally accepted that fracture toughness of fiber-reinforced polymer composites is affected by loading rate in an atmospheric presure condition. For a present study, the loading rate effect on the fracture toughness of fiber-reinforced laminated composites in the hydrostatic pressure condition was investigated. For this purpose, fracture tests have been conducted using carbon/epoxy composites applying three steps of the strain rate at 270 MPa hydrostatic pressure condition. The loading rates applied were 0.05%/sec, 0.25%/sec, and 0.55%/sec. Fracture toughness was determined from the work factor approach as a function of applied loading rate. The result showed that fracture toughness decreased as the loading rate increased. Specifically, the fracture toughness decreased 12% as the loading rate increased from 0.05%/sec to 0.55%/sec.

• Ocean and Polar Research
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• v.24 no.1
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• pp.93-114
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• 2002

Legal regimes of major countries actively involved in wetland programs including USA, Japan, Germany, Netherlands, and Denmark, show that these leading nations have developed their own legal regimes and policies for the conservation and restoration of wetlands since early 1990s. The main feature of their position is to preserve, create and restore wetlands, including tidal flats. However, this approach, so called 'mitigation' policy, is thus far, not a fully established policy but an evolving one. For Korea, there are only a few laws and policies which hint at the importance of creating coastal wetlands as a conservation measure, however, most of those systems only exist as vague provisions which lack any tangible and compulsory implementing procedures and technical guidelines. It seems that it is necessary to strengthen the legal measures for conserving coastal wetlands in Korea including specifying economic assessment methods and funding sources for the creation, restoration and rehabilitation of tidal flats to firmly establish a national wetland mitigation policy.

• Structural Engineering and Mechanics
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• v.37 no.5
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• pp.561-573
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• 2011

For efficient calculation of natural modes of structures, a numerical scheme which accelerates convergence of the subspace iteration method by employing accelerated starting Lanczos vectors was proposed in 2005. This paper is an extension of the study. The previous study simply showed feasibility of the proposed method by analyzing structures with smaller degrees of freedom. While, the present study verifies efficiency of the proposed method more rigorously by comparing closeness of conventional and accelerated starting vectors to genuine eigenvectors. This study also analyzes an example structure with larger degrees of freedom and more complex constraints in order to investigate applicability of the proposed method.

• Ocean and Polar Research
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• v.30 no.3
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• pp.347-349
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• 2008

A single juvenile of the jawfish Stalix toyoshio (24.0 mm standard length) was collected from the South Sea of Korea at a depth of 135 m during box-corer sampling. The specimen was characterized by the absence of stripes on both the body and vertical fins, well-developed cephalic pore systems, yellowish body and fins, six transversely-forked dorsal fin spines, and five mandibular pores. Here, we describe the specimen, which represents the first record of S. toyoshio from Korea and the second record from the northwestern Pacific.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.147-152
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• 2005

This paper proposes an evaluates a new approach to detect ships as targets from Radarsat-1 SAR (Synthetic Aperture Radar) imagery in the vicinity of Korean peninsula. To be more specific, a labeling technique and morphological filtering in conjunction with some other methods are employed to automatically detect the ships. From the test, the ships are revealed to be detected. For ground truth data, information from a radar system is used, which allows assessing accuracy of the approach. The results showed that the proposed approach has the high potential in automatically detecting the ships.