• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.229-238
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• 2022

This paper addresses on the International technical trends, standards, and development status of terrestrial radionavigation system to provide more accurate and fail-safe Positioning, Navigation, and Timing (PNT) Information available in maritime navigation environment. We analyze the performance result of pilot service in enhanced Long range navigation (eLoran) testbed environment using Low Frequency (LF) signal, and describe the development status of Ranging-Mode (R-Mode) system using Medium Frequency (MF) and Very High Frequency (VHF) to meet the Harbor Entrances and Approaches (HEA) requirement of International Maritime Organization (IMO) within 10m position accuracy. Furthermore, we present an architecture for integrated service of satellite-terrestrial navigation system and future maritime applicable fields. As the core information infrastructure of future navigation for 4th industrial revolution, this paper will be contributed to determining the direction of present and future to provide fail-safe PNT service with Global Navigation Satellite System (GNSS) based on the technical enhancement of terrestrial integrated navigation system.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.491-500
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• 2018

Due to changes in the distribution industry, inner harbors have been on a sharp decline in the recent past. However, through the application of the right development plans, such harbors can be revitalized into vibrant urban areas again. The importance of inner harbors has been recognized by the relevant authorities in Korea which are now pushing forward with redevelopment plans for its inner harbors. This study proposes a new approach to redevelopment plans based on the recognition that inner harbors have unique characteristics involving both inland areas and the ocean. In the study, representative inner harbors were selected and analyzed comparatively according to two distinct concepts of location: the Gateway Concept and the Central Place Concept. Based on these concepts, the conditions of the inner harbors were examined. Their location can be typed, and development directions were proposed according to their types and conditions. However, difficult points such as isolation and separation between an urban district and the harbor area, can be obstructions to their potential revival. An inner harbor needs to be considered as an intermediary, connecting place between the ocean and the city, not as another ordinary development area. In addition, a redevelopment plan should be accompanied by a strategic viewpoint to make the most of this feature.

• Ocean and Polar Research
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• v.26 no.2
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• pp.145-154
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• 2004

Surface energy and $CO_2$ fluxes have been measured over an ocean at Ieodo Ocean Research Station of KORDI since May 2003. Eddy covariance technique, which is a direct flux measurement, is used to quantitatively understand the interaction between the ocean surface and the atmospheric boundary layer. Although fluxes were continuously measured during the period from May 2003 to February 2004, the quality control of these data yielded <20% of data retrieval. The atmospheric stability did not show any distinct dirunal patterns and remained near-neutral to stable from May to June but mostly unstable during fall and winter in 2003. Sensible heat flux showed a good correlation with the difference between the sea water temperature and the air temperature. The maximum fluxes of sensible heat and latent heat were $120Wm^{-2}$ and $350Wm^{-2}$ respectively, with an averaged Bowen ratio of 0.2. The ocean around the tower absorbed $CO_2$ from the atmosphere and the uptake rates showed seasonal variations. Based our preliminary results, the daytime $CO_2$ flux was steady with an average of $-0.1 mgCO_2m^{-2}s^{-1}$ in summer and increased in winter. The nighttime $CO_2$ uptake was greater and fluctuating, reaching up to $-0.1 mgCO_2m^{-2}s^{-1}$ but these data require further examination due to weak turbulent mixing at nighttime. The magnitude of $CO_2$ flux was positively correlated with the half hourly changes in horizontal mean wind speed. Due to the paucity of quality data, further data collection is needed for more detailed analyses and interpretation.

• Ocean and Polar Research
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• v.26 no.1
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• pp.43-50
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• 2004

The diffusion model, which considers diffusion and sorption, is proposed. The FEM program developed on the basis of the diffusion model provides the estimation of chloride concentration according to cyclic humidity and sorption. After the humidity diffusion analysis is carried out, the chloride ion diffusion and sorption analysis are conducted on the basis of the preestimated humidity data in each element. Each element has different analysis variables at different ages and locations. At early ages, the difference between inner and outer relative humidity causes the chloride ion penetration by sorption. As the humidity diffusion reduces the difference with age, the effect of sorption on the chloride ion penetration decreases. By the way, the cyclic humidity increases the effect of sorption on the chloride ion penetration at early ages, and the quantity of chloride ion around steel at later ages. Therefore, the in situ analysis of chloride ion penetration for marine concrete structures must be performed considering the cyclic humidity condition and the long term sorption.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2000.09a
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• pp.30-36
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• 2000

목포해역에는 1981년과 1991년 및 1994년에 영산강하구언과 영암방조제 및 금호방조제가 각각 완공된 바 있으며, 이들 하구언과 방조제의 위치를 전반적인 목포해역의 형상과 수심도와 함께 Fig. 1에 도시하였다. Fig. 1에서 화원반도와 압해도 사이의 2개 섬으로 분리된 3개 수로를 남쪽부터 순차적으로 목포구, 중구, 북구라 하는데, 목포구의 단면이 월등히 커서 내측 수역과의 해수교환은 주로 목포구를 통해 이루어지며, 목포해역에서 목포구의 특별한 기능은 본문에서 여러 번 기술되고 있다. (중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.81-88
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• 2004

We review the adaptation strategies of the 21st climate change in an application to sea level rise. For the development of appropriate adaptation strategies on the coast vulnerable to the sea level rise, we have to consider the issues such as where to adapt, how to adapt, and when to adapt. The coastal target needed adaptation can be found by the evaluation of adaptive capacity of the coastal zone which requires the understanding of impacts and adaptive potential of the natural and socioeconomic systems in the coastal zone. Planned adaptation options to sea level rise can be classified into three generic approaches as managed retreat, accommodation, and protection In practice, the implementation of the options requires the analysis of land use, degree of vulnerability, cost and benefit, etc, and may be combination of the options rather than one approach. In terms of the response timing, the adaptation can be grouped as anticipatory and reactive ones. Generally it is more effective to consider both anticipatory and reactive adaptations at the same time for the impacts of future sea level rise. Due to the scientific uncertainty of climate change issues including sea level rise, the adaptation processes have to be designed to deal with a series of processes such as information md awareness establishment, planning and design implementation, and monitoring and evaluation in continuity and long-term period.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.631-639
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• 2007

We examined diurnal and seasonal variations of ozone ($O_3$) concentrations and its relation to meteorological parameters observed at the Ieodo Ocean Research Station ($32.07^{\circ}N$, $125.10^{\circ}E$, 36 m above sea level) during June 2003 and May 2005. Over the 2-year period, the mean ozone concentration was $49.5{\pm}15.5\;ppbv$. Ozone concentrations show great variability with a monthly mean up to 68.2 ppbv in May 2005 and seasonal variations with being highest in spring and fall, and lowest in summer. However, the amplitude of diurnal variation was less than ${\sim}4\;ppbv$ with a maximum at $3{\sim}4\;p.m.$ and minimum at $7{\sim}8\;a.m.$ HYSPLIT backward air trajectory indicated that the air masses with higher ozone came from the north or northwest and those with lower ozone arrived mainly via southerly or southeasterly. Ozone distributions at Ieodo Ocean Research Station were observed to be significantly impacted by long-range transport and regional scale air circulation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.113-127
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• 2007

In this study, a model to calculate the expected total construction cost is developed that simultaneously considers the rehabilitation cost related to the sliding of the caisson, the economic damage cost due to harbor shutdown in the event of excessive caisson sliding, and the economic damage cost due to temporal operational stoppage by excessive wave overtopping. A discount rate is used to convert the damage costs occurred at different times to the present value. The optimal cross-section of a caisson is defined as the cross-section that requires a minimum expected total construction cost within the allowable limit for the expected sliding distance of the caisson during the lifetime of the breakwater. Two values are used for the allowable limit: 0.3 and 0.1 m. It was found that the economic damage cost due to harbor shutdown by excessive caisson sliding is more critical than the rehabilitation cost of the caisson or the economic damage cost by excessive wave overtopping in the decision of the optimal cross-section. In addition, the optimal cross-section of the caisson was shown to be determined by the allowable limit for the expected sliding distance rather than the minimum expected total construction cost as a larger value is used for the threshold sliding distance of the caisson for harbor shutdown.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.781-786
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• 2010

In this study, a new concept of ocean transport system, called the mobile harbor serving for a short distance transport of containers with cargo handling cranes between mother containerships and coastal ports, is introduced. Instead of direct berthing a very large containership at the coastal port, Mobile Harbor is moving to the offshore mooring basin with enough water depth condition. Therefore, investigation of the coastal environment, technical condition and limitation of the domestic trade ports for the application of Mobile Harbor, is essential process. To figure out the accessibility of mobile harbor, the environmental conditions, the cargo handling capacity and marine traffic volume and flow pattern has been analyzed with the tools for marine traffic simulation and virtual navigation aids system. The most proper Mobile Harbor mooring areas among trade ports of the south and east coast are selected by analyzing the obtained information and evaluating its application: (1) Under natural environmental conditions such as air and sea weather, three candidate areas are selected such as Masan port, Ulsan port, and Busan(New port) port. (2) Under marine traffic and appropriateness of water facilities, three candidate areas are selected as Mokpo port, Busan(New port) port, and Donghae & Mookho port (3) For a region-based analysis considering handling capacity and the local managed trade ports in vicinity, three candidate areas are selected as Busan region, Yosu & KwangYang region, and Mokpo region. Through this study, the basic guideline for selection of optimum trade port and offshore mooring basin for mothership and Mobile Harbor is recommended. In order to apply the Mobile Harbor to the real water, navigaton aids as the virtual route identification with AIS must be introduced for maritime safety in the vicinity of Mobile Harbor area which berthing and cargo handling is being conducted.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1018-1020
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• 2003

The costal area where takes up over 32% in domestic teritory is considered as very importantly because it has not only economic facilities such as harbor and an industrial complex but also recreation facilities. Moreover, the tidal flat area has been used as culture ponds and salt farms because this area is occupied by various oceanic species. Also, the tidal flat area has played an important role to purify ocean pollution and maintain an ecosystem. However, the costal ecosystem has seriously threatened by domestic reclamation projects and a large-scale tide embankment during recent 10 years in Korea. This serious problem results in loosing 34%(810$km^2$) of the entire domestic costal area. In this paper, the micro-landform in the tidal flat area, which is called as Garolim bay in Korea, is classified by using Landsat TM images also verified through a filed report. Through the result of this, the tidal flat area is expected to manage efficiently especially through analyzing sediment environment and characteristic of grain size by using satellite images.