• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.25-27
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• 2020

현재의 도시는 관계성 희박화, 익명성 등의 문제로 커뮤니티 활성화가 과제로 존재한다. 일본 오사카는 물의 도시를 표방하며, 수변공간의 가치를 재검토하고 재생을 도모하고 있으며, 카모가와를 비롯한 수변공간은 도시 가운데 개방적 공공장소로 존재하면서 매력적인 공간 창출을 도모하려는 움직임이 지속되고 있다. 본 연구에서는 일본의 수변공간 활성화에 착안하여 지금까지 이용되어온 방식과 사람들의 행동을 규명하는 것으로 시사점을 얻는 것을 목적으로 하고 있다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.53-59
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• 2024

The reproductive biology of the Washington clam Saxidomus purpuratus, from Yeosu, Korea was investigated based on 699 individuals collected from January to December 2022. The sex ratio of this species was not significantly different from a 1:1 (male:female) sex ratio (P>0.05). Monthly changes in gonadosomatic index were analyzed to estimate the spawning season. The reproductive cycle of this species can be divided into the following stages: active (Jan.-Mar.), ripe (Mar.-Nov.), spent (Apr.-Dec.), and degenerative (Jun.-Dec.) stages. The spawning period ranged from March to December with the main periods being from April to June and from September to November. The shell length at 50% female group maturity (SL₅₀) was estimated to be 60.2 mm.

• Journal of Korean Port Research
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• v.1 no.1
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• pp.9-20
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• 1987

• Ocean and Polar Research
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• v.43 no.3
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• pp.127-140
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• 2021

At the estuaries of Bonggang and Miryong streams in the Korean southern coast, the spatiotemporal distribution and habitat environment of a nerite snail, Clithon retropictum (Gastropoda: Neritidae), which has been assigned as a legally protected species of Korea, were explored. Physicochemical environmental factors such as water temperature, salinity, tidal level distribution as well as biotic environments (chlorophyll-a concentration and epilithic microalgae composition) were monitored every month. The relationships between the environmental factors and spatiotemporal distribution of the nerite snail population were analyzed. Water temperature, salinity, and water level varied by season and lunar tidal rhythm. The spatiotemporal distribution of the nerite snail was mostly related to water salinity. Among epilithic algae which were the priority prey of snails, blue-green algae and green algae dominated in summer and autumn, while diatoms predominated during winter and spring. Chlorophyll-a concentration was highly and positively correlated with the population density of the nerite snail. The correlation coefficients were different depending on the taxon (Family) of epilithic algae. The mean population density was 302.2 inds m^-2 and 271.8 inds m^-2 in Bonggang Stream and Miryong Stream, respectively. The egg capsules of the nerite snail in the two habitats were observed from March (in Bonggang Stream) or April (in Miryong Stream) to August, and newly hatched juveniles recruited in the habitats from August were assessed with regard to frequency distributions of shell width. The occurrence of large-sized snails in upper stream reaches of both Bonggang and Miryong indicated the movement of spats from the mouth to the upper reaches during the whole life cycle.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.889-897
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• 2018

Since students of the College of Maritime Sciences will become professionals contributing to the development of the Korean shipping industry after graduation, they are required to successfully complete school life including theoretical and practical curriculum with health promotion behavior. The purpose of this study was to investigate the factors influencing health promotion behavior by students of the College of Maritime Science in order to collect basic data through a survey for the development of health promotion programs. Health promotion behavior by students of the College of Maritime Sciences was less frequent than by other college students, and the levels of health promotion behavior sub-domains were lower in order of interpersonal relations, spiritual growth, stress management, nutrition, physical activity, and health responsibility. The most influential factors for health promotion behavior were learner participation, health promotion self-efficacy, self-esteem, and social support. It is necessary to develop a differentiated health promotion program considering the characteristics of students and to apply it systematically from the time of admission to improve health promotion behavior by students of the College of Maritime Sciences.

• Ocean and Polar Research
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• v.41 no.1
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• pp.1-10
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• 2019

Right after the 2007 Hebei Spirit Oil Spill phytoplankton ecosystems were investigated for 11 years based on the seasonal monitoring of the composition and abundance of phytoplankton species. Comparable time-series data from the 1989 Exxon Valdez or the 2010 Deepwater Horizon Oil Spill sites were not available. It was suggested that the ecological healthiness of phytoplankton ecosystems at EVOS sites had recovered after 10 years following the oil spill based on chlorophyll concentrations even though these concentrations only represented phytoplankton communities in most cases. Chlorophyll concentrations can only reflect limited aspects of highly complex phytoplankton ecosystems. During the last 11 years following the 2017 HSOS, extreme variabilities were met in the seasonally averaged ratios of diatoms to phototrophic flagellates including dinoflagellates based on the microscopic cell countings. Summer phytoplankton communities exhibited some cyclic interannual changes in dominant groups every 2-4 years. During the early years (2008-2010) cryptophytes or raphidophytes (Chattonella spp.) dominated alternately each year, which was repeated again in 2014, 2015 and 2017. Two thecate dinoflagellates, Tripos fusus and Tripos furca, together accounted for 52.5% and 50.0% of all organisms in the summers of 2011 and 2012, respectively, which was repeated again in 2018. Summer occurrence and dominance by the phototrophic flagellates including HABs (Harmful Algal Blooms) species as well as their interannual variabilities in the oil spill sites could be utilized as markers for the stable and long-term management of healthy ecosystems. For this type of scientific ecosystem management monitoring of chlorophyll concentrations may sometimes be insufficient to gain a proper and comprehensive understanding of phytoplankton communities located in areas where oil spills have occurred and harmed the ecosystem.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.81-87
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• 2021

Many merchant ships sail in the waters surrounding Jeju Island and many fishing vessels catch fish using gill nets, trolling lines, and so on. Meanwhile, marine waste has collected in the coastal waters of Jeju Island. However, there has been little research on the collection of marine waste in coastal waters. In this study, marine waste deposited in Jeju Island's northwest sea was collected using Jeju National University's training ship, and related vessels were analyzed for each gear type. According to the results, most coastal waters had abandoned fishing grounds, which were from fishing vessels, and a large proportion of them was gill net and trap fishing gear. To analyze how much marine waste is accumulating in a certain area and ship's stay time, we use automatic identification system (AIS) data to extract the time spent in the target sea, and the amount of marine waste per hour was analyzed in a unit distance of 1 ㎢. The average amount of marine waste generated per hour in the unit area was found to be 0.94 kg for gillnet fishing gear, 3.49 kg for trap fishing gear, 0.10 kg for trawl fishing gear, 0.11 kg for longline fishing gear, and 0.02 kg for other fishing gear.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.990-998
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• 2008

In this paper we achieve experimental data evaluation using SSB(Single-side band) modulation in the ocean. Present research in underwater communication is applying digital modulation, OFDM and MIMO system. However, Commercial modems using analog modulation techniques in oceans. So, we achieved experimental for modem appliance development of correct high quality in South Korea sea characteristics. This experimets achievd useing SSB analog modulation in Jin-hae shore of shallow water condition. Used data are tonal and LFM signal for getting underwater channel characterisitcs and female Korean speech for speech communications.

• Journal of Apiculture
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• v.34 no.1
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• pp.7-13
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• 2019

Vespid wasps (Vespa spp.) are the most noxious pests on apiculture, resulting in significant economic losses. Early monitoring and management are the first step to prevent the damages from vespid wasps. In this study, the acoustic signals from wasps and honey bees were measured by a microphone with a preamplifier and an analog-digital converter. In frequency analysis of the acoustic signals from wasps and honey bees, there were differences between the two species. While the fundamental frequency of the wasps was analyzed to be about 100 Hz with the strong harmonic frequencies, that of the honey bees was about 200~250 Hz. The 2nd harmonic signals from wasp were strongest while the fundamental ones from honey bees were. These different sound features generated by wasps or honey bees might be applied to develop the early monitoring system of the incursion of wasps to the apiary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.156-162
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• 2020

Since the early 20th century, there have been reviews and legislations regarding the legal status of the Government ships operated for non-commercial purposes. In particular, as criticized in the absolute theory of immunity in conventional international law, the sovereign immunity theory has become more vital as a restrictive theory for immunity. As per the customary international law and international law of the sea, non-commercial government vessels, including warships, are provided with sovereign immunity on the sea. National universities of Korea have built and operated training ships and survey ships for educational purposes, such as training high-grade mariners and fishing practices. These training ships sail not only on the national maritime jurisdictions but also on the maritime jurisdictions of other States and the high sea. Therefore, clarifying the legal status of national university training ships is one of the important factors in international navigation according to international law. However, it is not easy to answer the question of the legal status of the training ship. Hence, this article analyzes the parameters that define the Government ship operated for non-commercial purposes and examines whether national university training ships are in line with the relevant criterion. Furthermore, the article analyzes the scope of sovereign immunity in conventional international law and international conventions and identifies the scope of sovereign immunity enjoyed by the national university training ships according to international law.