• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.475-486
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• 2009

The geological survey of the Mokdo island is for the fist time conduted in Korea history. The island had erupted before $70{\sim}80$ million years as a strato-volcano. The original volcano had been dissected for long periods up to the skeletal stage through the planeze stage. If the island area is surveyed afterwrds in detail, the position of crater is available to be found, either. The coastal terrace is found at 50m level in Mokdo island which is correlated to its fourth plane. The microgeomorphological features as coastal terrace, cliff, sea cave, wave-cut bench, sea stacks, notch, and tafoni, etc. were described. The Mogdo island is located off Molundae at the extension of Nagdong Jeongmaeg(낙동정맥 洛東正脈) showing a "floating turtle". The name of Mogdo island is needed to change to the "Yoo-goo-do" which means the swimming turtle. The Mokdo island is as suitable tourist attraction for if has enough touism sesouccesein sea. The deuelopsment of coartal sightseeing anound lighthoure and uninhabited islands will hare an impontant effect upon construction of the oceanic capitol city of Busan Haabor. The master plan built up an arboretum on the island, a coastal oceanarium, a seaweeds garden under sea coast, and other oceanic culture-spaces is completed in the study.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.611-616
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• 2013

This paper studies relationship between typhoon and El Ni$\tilde{n}$o La Ni$\tilde{n}$a events by using 25 years meteorological data of KMA and JMA. The results are listed below. Annual mean number of typhoon's occurrence in El Ni$\tilde{n}$o event year is 23.9, and that in La Ni$\tilde{n}$a event year is 24.9. The number of typhoon's occurrence decreases in El Ni$\tilde{n}$o event year. Mean central minimum pressure and mean maximum wind speed in El Ni$\tilde{n}$o event year are 959.3hPa and 35.8m/s, and those in La Ni$\tilde{n}$a event year are 965.5hPa and 33.7m/s respectively. Intension of typhoon is stronger in El Ni$\tilde{n}$o event year than La Ni$\tilde{n}$a event year. To be more specific mean central minimum pressure is lower 6.2hPa and mean maximum wind speed is stronger 2.1m/s. This result is closely connected with sea area of typhoon's occurrence. Typhoons in El Ni$\tilde{n}$o event year are more likely to occur in east of 150E and south of 10N, but those in La Ni$\tilde{n}$a event year are more likely to occur in 120-150E and north of 20N. Typhoons which occur in east of 150E and south of 10N can be stronger because the typhoons move in broad sea area of high sea surface temperature in western North Pacific.

• Journal of Korea Port Economic Association
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• v.35 no.2
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• pp.1-20
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• 2019

This study aims to establish a method for activating Korean ship finance through an analysis on the development of Chinese ship finance market, which has grown rapidly in recent years. It focuses on its main institutions, laws and policies, strengths and weaknesses, market share, and development status. Because 80.7% of South Korea's economy depends upon foreign trade and 99.7% of the South Korea's traded volume is transported by ships, shipping has assumed an important role in Korean economy. However, since the global financial crisis, Korean shipping and shipbuilding industry has been facing difficulties and Hanjin, the biggest Korean shipping company, went bankrupt in 2017. One of the key aspects of the competitiveness of the shipping and shipbuilding industry is acquiring competitive shipping assets; therefore, stable and smooth supply of ship finance is crucial for the development of the shipping and shipbuilding industry. Given this background, the study analyzed how the Chinese ship finance market has grown rapidly in the past 30 years and identified the problems, strengths, and weaknesses of the Chinese ship finance. The analysis on the status of the Chinese ship finance market is expected to suggest a direction for establishing methods for activating the Korean ship finance market, which is facing scarcity of finance, even as the global ship finance market has remained depressed since the global financial crisis. Although this study focused exclusively on the Chinese market, future research can draw conclusions from a comparative analysis that includes the Japanese ship finance market; the conclusions obtained would contribute to the establishment of long-term policies and plans for Korean ship finance.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.447-452
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• 2020

Extratropical cyclone in winter season is very important in safe operation of ships because it is a major cause of marine accidents due to its strong power. In this study, we used meteorological data, to analyze extratropical cyclones occurring near the 1st Pacific polar front from December 2019 to February 2020. The analysis results are as follows. During those three months, we recorded 41 extratropical cyclones, 8 of which were remarkably developed. The central pressure of the strongest cyclone was 947hPa. The highest number of cyclones were generated in the East P acific Ocean around J apan (16), followed by the areas around Korea, the East China Sea, and the southern Sea of J apan. The cyclones followed five major tracks with a common northeast pattern. We thus concluded that the optimal route for a ship encountering an extratropical cyclone in the North P acific in winter would be south of the cyclone's center traveling eastbound and north of the center traveling westbound.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.219-219
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• 2022

지구 온난화와 함께 발생하는 해수면 상승은 한반도의 해안지역을 비롯하여 울릉도 등 도서지역 전반에 걸쳐 진행 중이다. 또한 해수면의 온도 상승으로 인한 열대저기압의 생성 시 에너지 공급이 증가하며 연안으로 내습하는 파랑 내습 에너지가 커지게 된다. 경상북도 울릉군에 위치한 남양항은 최근 2019년 태풍 다나스 및 2020년 태풍 마이삭 등에 의해 고파랑 혹은 침수 피해가 발생하여 항 내에서는 물양장과 선박이 파괴되고 방파제가 전도되는 등의 피해가 속출하였다. 동해안의 태풍 내습, 지구 온난화와 저기압 발달에 의한 수위 상승 등과 같은 다양한 해양기후를 고려한 연안 구조물의 파랑 영향을 검토하는 것이 중요할 것으로 판단되었다. 기상청 태풍센터에서 제공하는 1979년부터 2020년까지 한반도 해역에 내습한 태풍 중 울릉도에 영향을 미친 태풍은 18개로 울릉도 인근에 영향을 준 내습 태풍을 10년 단위로 분석해 보면, 1980년대 3개, 1990년대 2개, 2000년대 8개, 2010년대 3개, 2020년 2개로 2000년대에 울릉도 영향권에 들어간 태풍이 가장 많았으며, 심해파 추산 기간 이후 2020년 1년 동안 울릉도 인근으로 마이삭, 하이선과 같은 2개의 태풍이 연속적으로 영향을 주었다. 울릉도에 영향을 미친 18개 태풍을 대상으로 일본 기상청(JMA)에서 제공하는 1시간 바람장을 이용하여 파랑 후측 수치 모의를 수행하였으며, 해양수산부와 기상청 관측 부이를 이용하여 파랑에 대한 정확도를 확보하였다. 고파랑 내습 시 연안에 조우하는 수위 조건은 파랑 에너지의 증가를 결정하게 되며, 항만 구조물의 설계에 적용되고 있는 약최고고조위 이상(4대분조의 최대 조위)의 최극조위 조건에서 해안 구조물에 월파 및 침수 피해를 주는 요인으로 작용할 수 있다. 이를 바탕으로 울릉도 남양항에서 폭풍 시 내습한 최극고조위(0.65m)와 IPCC 5차 보고서에 제시한 최악의 시나리오(RCP 8.5) 조건에서 울릉도에서 확인된 0.79 cm 상승고를 반영하여 범람위험평가를 광역에서의 계산 결과를 입력자료로 하여 준 3차원 비 정수압 파랑 변형 수치 모형인 MIKE 3 Wave를 사용하여 실험하였다. 해수면 상승에 의한 수위 상승고는 연안 파랑 증가에 영향을 주었으며 연안 구조물의 침수 피해에 영향을 줄 것으로 판단되었다. 월파 차단, 파랑 차폐의 목적으로 건설되는 구조물의 규모 및 천단고 등을 설정하는데 설계 수위의 선정은 중요하다. 수치 실험 결과를 바탕으로 방파제 및 호안의 범람 위험 평가를 수행하고 구조물 설계 시 이러한 해수면 상승고가 반영된 설계가 중요하다는 것을 위험 평가를 통해 확인할 수 있다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.55-55
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• 2011

연안 및 해안공학의 발달과 더불어 부유식방파제의 기능적 효율성이 중요시 되고 있다. 흔히 사용되어오던 착저식방파제는 설치에 많은 시간과 경비가 소요되고 환경 및 생태계에 많은 변화를 줄 수 있으며, 설치 예정지의 수리학적 특성 등의 여건에 많은 제약을 받는 단점이 있다. 부유식방파제는 일본 등의 선진국을 중심으로 활용이 잦아지고 있는 방파제로서 수면 위에 설치되기 때문에 수중 생태계에 미치는 영향이 적은 친환경방파제이다. 또한 기존에 시공된 중력식방파제와는 달리 수심에 제한을 덜 받고, 공사기간이 짧기 때문에 경제적이다. 실제 시공사례로는 2007년 마산 원전항에 완공된 부유식방파제가 대표적이며, 지금까지도 부유식방파제에 대한 여러 연구자들의 관심이 증가하고 있는 추세이다. 방파제뿐만 아니라 우리나라처럼 국토의 면적이 작은 지역에서 증가하는 해상물동량을 소화하기 위해서 부유식방파제 등을 이용한 항만의 시공이 필요한 실정이다. 이러한 부유식방파제의 분석적인 측면에 있어서 수치해석은 파랑과 구조물의 상호작용을 해석하는 데 한계가 있으며, 부유식방파제 단면형상을 정확하게 재현할 수 없으므로, 수리모형실험을 통한 부유식방파제의 연구가 필요할 것으로 판단된다. 최근 기술의 발달로 인한 유동장 해명이 가능해 졌으며, PIV(Particle image velocimetry) 및 LDV시스템은 다양한 분야에서 응용되고 있다. 특히, LDV시스템은 측정하려는 한 지점에 대하여 레이저 빔을 단면(Cross-section)으로 만들고 입자의 산란광을 후방산란(Back scatter)으로 받아서 도플러 효과를 이용, 속도에 대한 주파수를 획득하며, 유속을 측정하는 장비로 매우 높은 정확도와 비접촉식 이라는 장점을 가지고 있다. 또한, PIV 시스템에 비하여 측정시간이 오래 걸리는 반면 데이터를 가공하지 않고 활용할 만큼 높은 정확성을 가지고 있다. 본 연구에서는 수리모형실험을 통하여 단독형, 2열형 및 3열형 부유식방파제의 형상, 흘수 및 거리를 변화시키며 유동장을 수집하였으며, 방파성능에 따른 와의 생성 및 소멸시점에서의 파랑변형과의 관계를 분석하였다. 방파제의 형상과 흘수를 달리하여 수리모형실험을 수행하였으며, 와류의 상관관계를 분석하였다. 또한, 연직 2차원 Navier-Stokes 방정식 모형을 이용하여 수치모형실험을 수행하였으며, 수치모형실험 결과와 수리모형실험 결과를 비교 분석하였다. 후방방파제에서 발생되는 파랑은 입사파의 주기가 길어질수록 상대적으로 커지는 현상을 보였으며, 흘수심이 깊어질수록 전방방파제 입사 면에서 자유 수면이 높게 관측되는 결과를 보였다. 또한, 비교적 장주기파랑에 해당하는 입사파랑의 경우 전달파고비 산정에 있어서 설계기준인 0.5를 대다수 초과하는 반면, 3열형 구조에서는 대부분이 0.5이하로 상당히 높은 방파성능 결과를 나타내었다.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.207-215
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• 2017

With rapid development of IT technology and biotechnology, human lifespan is extended rapidly, and we are living in the era where aging becomes the social issue. Due to this aging problem, manpower is mainly replaced by Automated Guided Vehicles (AGV) in manufacturing factories or warehouse logistics transportation. Rate of AGV use increases sharply every year. AGVs, which were used only in Smart Factories, extends its usage into indoor and outdoor operation by changing their usages to container transportation that can carry huge containers in the harbor. With the expansion of AGVs usage, the importance of RCS (Remote Control System) is also increased. In this study, we surveyed and analyzed the characteristics and technology trends of technical features of AGV's RCS that are developing in various ways to establish quality evaluation system of AGV RCS. Based on this, and by referring to international quality assessment standards, ISO/IEC 25000 series, we derived evaluation items on functional suitability and usability to secure reliability of AGV RCS. Also, it is our intention to develop evaluation model using those derived usability and reliability evaluation items.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.6
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• pp.349-356
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• 2013

The purpose of this study is to review and overcome the limits of the existing design wave model applied to such waters as those located inside bays or near islands where the impact of wind influenced waves are more dominant, due to the nature of topographic isolation, than the influence of direct waves coming from the open sea. Although the existing model for an inside bay design wave is excellent for considering wind factors and very adaptable to topographically complicated areas compared to other models, it is difficult to show the wave diffractions and reflections caused by large scale structures or topographic features in the region. The study examined the various methods capable of taking into account wave diffraction, the angle of wave reflection, and changes in water depth. As a result of applying the modified design wave model to the target situation (inside bay or near island areas), it was found that the reliability of the design wave height around marine structures was improved, compared to the existing models. Therefore, it is fair to predict that the new model could provide more accurate design waves in the design of marine structures.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.77-91
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• 2012

Recently, construction of housing sites, complexes, roads, ports and airports is increasing for high-intensity use of the country and balanced development between regions. Presently, constructions are being conducted at soft ground. Consequently, engineering problems as long-term settlement of the ground, differential settlement, local structural damage have been reported consistently at construction site. In particular, long-term subsidence of the ground as various constructions and loads by the load will necessarily occur in the soft ground of west-south coast and inland coast. Therefore, in this study, regional proper analysis methods of the Hyperbole method, Hosino method, $\sqrt{S}$ method, Asaoka method etc as existing long-term settlement prediction methods have been examined and a study on new prediction method was conducted through deduction of a generalized equation. Correlation coefficients of soil properties and construction conditions has been analyzed and a matching coefficient of long-term settlement characteristics has been deducted. Comparison and analysis of monitoring data and numerical analysis results of 16 local area have been conducted.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.355-358
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• 2009

Due to growth of electronics and control devices, automation and situational awareness systems have been applied by automobile. Vision systems with the introduction of unmanned system being actively developed, but are still high price and visual information is passed through the cable, because of cars are difficult to install. In this paper, can be installed inside the car at low-cost, simple image processing device through a wireless communication know the obstacles and the alarm system based on Zigbee wireless communication, infrared and ultrasonic sensors to monitor the situation through with easy parking cars outside the system design was implemented.