• Journal of Welding and Joining
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• v.34 no.2
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• pp.22-29
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• 2016

Recently, Application of composite materials are increased in transport area for weight reduction. Also, Related technical developments have been implemented actively at domestic and abroad. In particular, The carbon fiber has high strength and ultra light property higher than stainless steel, aluminum, GFRP as Eco-friendly material. Carbon fiber contribute to improving the environmental effect such as fuel saving, expansion of loadage, reducing the exhaustion of carbon dioxide through the weight reduction of transport area. In addition, The carbon fiber is applied to the ship in the area of race yacht, luxury cruise boat as weight reduction and high added-value materials, but there is limited application for general boat because price of carbon fiber is very expensive. For the weight reduction of general boat hull, being used as structure materials, glass fiber and carbon fiber are applied to hull with form of hybrid composite materials, but application of domestic and research for development are incomlete. In this study, An evaluations of mechanical strength property and fatigue strength are performed on composite materials by hybrid weaving of glass fiber and carbon fiber and composite materials forming method by hybrid forming.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.1
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• pp.49-55
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• 2011

Sound insulation performance of a unit cabin mock-up is studied, where two identical rooms simulating cruise ship cabin are installed. STL (Sound Transmission Loss) measurement in the mock-up shows that STL of the partition between rooms is degraded by imperfect door ceiling and gap between wall and floor. It is also observed that gap around lighting and electrical outlet slightly affect the STL in high frequency ranges, since lighting and electrical outlet are supported by mineral wool in the back side due to fire-resistance requirement. Even after all possible gaps are sealed, STL of the partition is found to be lower than that measured in the laboratory by 9 dB. Measurement of SBN (Structure-Borne Noise) reveals that flanking transmission of SBN along the steel deck floor can severely deteriorate STL of the partition. Statistical energy analysis (SEA) of the mock-up confirms importance of the floor SBN control, in which increasing damping is essential to ensure high STL.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.220-226
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• 2005

This study evaluated the composition and distribution of marine litters on the sea-bed of the East China Sea. Surveys have been conducted by a benthic trawlnet of Dong-baek training ship of Yosu national university during the cruise of 2002-2004. Distribution density showed high value in C5 (north-western area of Jeju Island) with $110.3kg/km^2$ and those of annual mean were about $31-43kg/km^2$. Fishing gears such as nets, pots, octopus jars and etc. were about 42-72% of debris collected in the East China Sea. Composition ratio of rubber, vinyl. metal, plastic, glass, wood, cloth and etc. were within 25% except C5. Rope and drum showed strong fluctuations with 0-30% according to the trawling sites. Some vinyls and nets made in Korea, China and Japan were much collected. It is estimated that fishing gears were discarded to the sea by fishing operation, deliberately or not. An comprehensive program including continuous research, monitoring for marine litters in the Korean sea were necessary.

• Maritime Security
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• v.1 no.1
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• pp.241-271
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• 2020

The military technology currently receiving the most attention is the hypersonic missile. hypersonic is faster than the speed of sound or Mach 5+. The vast majority of the ballistic missiles that it inspired achieved hypersonic speeds as they fell from the sky. Rather than speed, today's renewed attention to hypersonic weapons owes to developments that enable controlled flight. These new systems have two sub-varieties: hypersonic glide vehicles and hypersonic cruise missiles. Hypersonic weapons could challenge detection and defense due to their speed, maneuverability, and low altitude of flight. The fundamental question of this study is: 'What effect will the hypersonic missile have on the maritime strategy?' It is quite prudent to analyze and predict the impact of technology in the development stage on strategy in advance. However, strategy is essential because it affect future force construction. hypersonic missiles act as a limiting factor in securing sea control. The high speed and powerful destructive power of the hypersonic missile are not only difficult to intercept, but it also causes massive ship damage at a single shot. As a result, it is analyzed that the Securing sea control will be as difficult as the capacity of sea denial will be improved geographically and qualitatively. In addition, the concept of Fortress Fleet, which was criticized for its passive strategy in the past, could be reborn in a modern era. There are maritime power projection/defence, SLOC attack/defence in exploiting sea control. The effects of hypersonic missiles on exploiting sea control could be seen as both limiting and opportunity factors.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.3
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• pp.76-93
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• 2017

This thesis recapitulates the current status of Nujeongs(樓亭) by the Han River(漢江) from the late Joseon dynasty, and to contemplate the possible options regarding their restoration. The book Yeon-gang-jeong-sa-gi(沿江亭?記) written by Eom Gyeong-su(嚴慶遂) in 1716 was selected as an object of study. After Hanyang was selected to be the capital of Joseon, Han River was considered to be the greatest venue to visit to take some time off and enjoy the view. The nobleman of the Joseon dynasty built Nujeongs around the riverside and enjoyed boating inthe current status of Nujeongs(樓亭) Han River. Eom Gyeong-su, after traveling on a boat to personally collect information, combined such information with preexisting information to create a well-organized and thorough list of the 29 Nujeongs built by the riverbank, which can be found in his book Yeon-gang-jeong-sa-gi. It is probable that a closer look into Yeon-gang-jeong-sa-gi will reveal more information regarding the general atmosphere of the era, which focused on the history and culture of Han River, and will also enable a more thorough research involving the Han River Nujeongs. The Nujeongs listed in Yeon-gang-jeong-sa-gi were analyzed in this paper. Based on the explanations found in Yeon-gang-jeong-sa-gi, the locations of the 29 Nujeongs were checked and reconfirmed, and the origins and the meanings behind their names were analyzed. In addition, the history of the Nujeongs were recapitulated with information gained from the basis of the fact that Yeon-gang-jeong-sa-gi was written in 1716, The origin of each Nujeongs were revisited, and the history of their change and demise were analyzed. Lastly, the sceneries around each Nujeongs were analyzed based on the poetries that were written and read in the respective Nujeongs, and the general taste for the arts in the era was analyzed. Some Nujeongs remain in the form of paintings, enabling us to take a closer look at the institutions and other aspects of the era. The analysis of Yeon-gang-jeong-sa-gi by this paper has revealed the location of some Han River Nujeongs that were unknown previously. Also, the revelation of some history regarding certain Nujeongs that were unknown previously has created an opportunity for the reinterpretation of the spaces surrounding Han River, and also the opportunity for a new story. Han River has lost most of its old self due to repeated exploitation. However, there are some areas where traces of the original form remains and that may be restored, and some areas may be relocated and restored based on existing paintings. Yeon-gang-jeong-sa-gi in particular may provide us with numerous possible options to reinvigorate and restructure the riverside with a more modern interpretation, especially in relation to the Han River cruise ship, as it is a book written after traveling Han River on a boat.