• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.235-246
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• 2002

The fish farming using net cages has been developed in many semi-closed bays in the southern coast of Korea for the last two decades. The intensive cage cultures of fishes generate considerable amounts of organic waste in the form of uneaten food and faeces. In order to evaluate the effect of fish farming activities we collected the benthic macrofauna near the fish farm area located in Wolho Islet of Gamak Bay and in Haklim Island of Tongyeong in November 1998. Benthic macrofaunal assemblages showed dramatic changes in species number, species diversity, and faunal abundance in the region of the fish farm. These changes were clearly observed even at a distance of up to 30 m from the fish farming cage area. Within 5 m from the cage, there was a zone with low species diversity and highest density, dominated by opportunistic polychaete worm, Capitella capitata. By a distance of 15-30 m, this zone presents highest species number and higher density. Our results clearly demonstrated that fish farm area was highly enriched with organic materials, and implied that the fish farm industry and adjacent benthic ecosystem in semi-closed bay will be seriously damaged by self produced organic wastes in the near future.

• Journal of Society of Preventive Korean Medicine
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• v.26 no.3
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• pp.41-48
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• 2022

Objectives : This study aimed to investigate the adequacy and satisfaction of the school doctor program of Korean medicine (especially sex education) for elementary school students, to examine differences in parents' perception or satisfaction according to the use of Korean Medicine. Methods : The participants were parents of one elementary school that provided sex education as the Seoul school doctor program of Korean medicine. A self-reported online survey was conducted. The questionnaire consisted of parents and children's experience in using Korean medicine, perception of the school doctor program of Korean Medicine, evaluation and satisfaction of school sex education. Results : The survey was conducted on May 14^th, 2022 during the school doctor program of Korean Medicine briefing session. A total of 92 parents participated in the survey, and the 88 respondents analyzed who voluntarily gave consent. Of the experience of Korean Medicine, 71 parents (80.68%) had lifetime, 16 (18.18%) respondents had within the last three months, and 40 (45.45%) said their children had. Parents' experience of using Korean medicine was related to that of their children's, but there was no difference in the satisfaction the school doctor program of Korean Medicine. Conclusions : The survey showed that parents of an elementary school where Korean Medicine doctors carried out school doctor program evaluated that the school doctor program of Korean Medicine had a positive effect on students' health. There was no difference between parents' satisfaction on school doctor program by the use of Korean medicine.

• The Korean Journal of Quaternary Research
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• v.24 no.2
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• pp.23-34
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• 2010

The purpose of this study is to clarify the characteristics of geomorphic surfaces and investigate their geomorphological development at Sinsong-ri archaeological sites by the classification of geomorphic surfaces. The sedimentary facies of trench 1, 2 and 3 were identified and pollen analysis was performed at site 3. The geomorphic surfaces are classified by hillslope, valley plain, alluvial fan and river terrace. Most of the study area is located on low hillsides and valley plains are connected with tidal flats extended from small river valley. Also, alluvial fans are distributed over the piedmont and narrow, long river terraces are developed downstream along the Sojeong-stream flowing between valley plain and hillsides. River valleys were deeply eroded during the Last Glacial Maximum (LGM) periods, responded to the lowest sea level among the hillslopes and valley plains are formed during the Holocene. The sedimentary facies are identified composed of basal gravel layers with coarse gravels and sands, relatively thick culture layer of the Bronze Age and thin layer during the early Iron Age in upper part study area. Thus, land uses during the Bronze Age people was performed more intensively comparing to the early Iron Age by deforestation for habitation.

• Journal of the Korean Geophysical Society
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• v.8 no.3
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• pp.159-167
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• 2005

Turbulent fluxes of sensible heat and latent heat were analyzed at King Sejong station in the austral summer of 2002 (December) and 2003 (January and February). Monthly mean air temperatures of January and February (2.2oC) were similar to those averaged over 1988 to 2001. Precipitation was less in January and greater in February than those averaged over last 14 years. In December of 2002 and January, there was precipitation primarily when easterly wind blew usually. The frequency of snowfall was equal to or larger than that of rainfall. In the mean while, precipitation primarily in forms of rainfall occurred with westerly wind in February. In addition, while for easterly wind, temperature and humidity was low, temperature and humidity were high in case of westerly wind. Based on flux footprint, measured flux mainly came from within 300 m with maximum of 40 m upwind, indicating the insignificant role of the sea around the study site. Half-hourly downward short wave radiation amounted up to ∼ 1000 Wm-2 and net radiation ranged from -50 to 600 Wm-2. Half-hourly sensible heat flux was positive at daytime with maximum of ∼ 400 Wm-2, except the 27th and 28th in February of 2003 when it was negative all day despite of positive net radiation at short daytime. Latent heat flux was positive with maximum of ∼ 130 Wm-2. Depending on wind direction, the partitioning of net radiation into the sum of sensible heat flux and latent heat flux was larger than 0.8, indicating the strong source of the land surface for the atmospheric heating. The daytime averaged Bowen ratio (=sensible heat flux /latent heat flux) was significantly greater than 1, indicating that sensible heat flux was the main source to heat the atmosphere over the site.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.325-332
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• 2008

To characterize the initiation, propagation and termination of Cochlodinium polykrikoides blooms in the southeast coastal waters of Korea, 2007, we have analyzed the data set of phytoplankton composition, physical and chemical water properties, and meterological data. The development of C. polykrikoides bloom in 2007 can be summarized in three steps. The first stage from middle of July to end of August was characterized by an unusually persistent and strong southerly wind. C. polykrikoides blooms established already by the strong wind in the middle of south coastal waters were advected intermittently into the study area. Accordingly, highly variable cell densities of C. polykrikoides were observed. At the second stage a favorable growing conditions for C. polykrikoides was developed, which was directed by changes in wind direction from south to northeast and thus enhanced transportation of offshore waters into inshore (August 8 to 30). C. polykrikoides bloom occurred through typical mechanism and showed high cell density. The last stage was represented by disappearance of C. polykrikoides. Typoon 'Nari' carrying heavy rain brought an unfavorable habitat to C. polykrikoides. Low saline condition formed in coastal water due to typoon effects continuously drove the dominant species to diatoms and flagellates which were prevailing over C. polykrikoides in this circumstances(from the middle of September). These stepwise processes could be the causative mechanism of the extraordinarily persistent C. polykrikoides bloom observed in southeast coastal water of Korea, 2007.

• Atmosphere
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• v.26 no.4
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• pp.509-522
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• 2016

Heavy snowfall events have occurred frequently in the Yeongdong region but understanding of these events have trouble in lack of snowfall observation in this region because it is composed of complex topography like the "Taebaek mountains" and the "East sea". These problems can be solved by quantitative precipitation estimation technique using remote sensing such as radar, satellite, etc. Two radars which are able to cover over Yeondong region were installed at Gangneung (GNG) and Gwangdeoksan (GDK). This study uses radar and water equivalent of snow cover to investigate the characteristics of radar echoes and the $Z_e-R$ relations associated with the 10 Yeongdong heavy snowfall events during the last 5 years (2010~2014). It was found that the heights which the probability of detection (POD) of snow detection by GNG radar is more than 80% are 3,000 m and 1,500 m in convective cloud and stratiform cloud, respectively. The vertical gradient of radar reflectivity is less decreased in convective cloud than stratiform cloud. However, POD by GDK radar are lower than 80% at all layers because the majority of Yeondong observational stations are more than 100 km away from GDK radar site. Furthermore, we examined $Z_e-R$ relation from the 10 events using GNG radar and compared the "a" and "b" obtained from these examinations at Sokcho (SC) and Daegwallyeong (DG). These "a" and "b" are estimated from radar echo at 500 m (SC) and 1,500 m (DG). The values of "a" differ in their stations such as SC and DG are 30~116 and 6~39, respectively. But "b" is 0.4~1.7 irrespective of stations. Moreover, the value of "a" increased with surface air temperature. Therefore, quantitative precipitation estimation in heavy snowfall events by radar echo using fixed "a" and "b" is difficult because these values changed according to those precipitation characteristics.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.181-191
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• 2016

We estimate the eruption history and magmatic eruptive volumes of each rock units to evaluate the volcanic eruption scale and volcanic hazard of the Ulleung Island. Especially, Maljandeung Tuff represents about 19~5.6 ka B.P. from $^{14}C$ dating, and Albong Trachyandesite, about 0.005 Ma from K-Ar dating in recent age dating data. These ages reveal evidences of volcanic activities within the last 10,000 years, indicating that the Ulleung Island can classify as an active volcano with possibility of volcanic eruption near future. Accumulated DRE-corrected eruptive volume is calculated at $40.80km^3$, within only the island. The calculated volumes of each units are $3.71km^3$ in Sataegam Tuff, and $0.10km^3$ in Maljandeung Tuff but $12.39km^3$ in accounting the distal and medial part extended into southwestern Japan. Volcanic explosivity indices range 1 to 6, estimating from the volumes of each pyroclastic deposits. The colossal explosivity indices are 5 in Sataegam Tuff, and 6 in Maljandeung Tuff in accounting the distal and medial part. Therefore, it is necessary for appropriate researches regarding possibility of volcanic eruption of the island, and establishment system of the evaluation and preparation for volcanic hazard based on the researches is required.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.353-360
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• 2010

The Kyunggi Bay in mid-west of Korea is a relatively large estuarine system that connects the Han River system with Yellow Sea. Due to macro-tidal range of more than 8 m, the urban estuary shows deep tidal channels and wide tidal flats. Since last 30 years, the coastal development is undergoing, yielding noticeable change in environment. Particularly the tidal flat dynamics are generally accepted as being related with tidal residual flows in this area (Kim et al., 2009). We have estimated the annual variation and vertical structure of residual currents with one-year long observed flows in two major tidal channels of Kyunggi Bay. The moving average method and tidal current harmonic analysis yield nearly the same results on residual flow. The residual flow in Jangbong channel ranges from 20 cm/s in summer to 30 cm/s in winter. It is noticeable that the residual flow in Jangbong channel is flood dominant throughout the year, while the flow in Seokmo channel is ebb-dominant residual flow with current speed range of 20-40 cm/s. Due to the baroclinic response of relatively shallow estuary, significant reduction of energy in bottom layers have been observed, indicating the importance of residual circulation to the tidal flat behavior.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.843-856
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• 2023

The global surge in maritime traffic has resulted in an increased number of ship collisions, leading to significant economic, environmental, physical, and human damage. The causes of these maritime accidents are multifaceted, often arising from a combination of crew judgment errors, negligence, complexity of navigation routes, weather conditions, and technical deficiencies in the vessels. Given the intricate nuances and contextual information inherent in each incident, a methodology capable of deeply understanding the semantics and context of sentences is imperative. Accordingly, this study utilized the SentenceBERT model to analyze maritime safety tribunal decisions over the last 20 years in the Busan Sea area, which encapsulated data on ship collision incidents. The analysis revealed important keywords potentially responsible for these incidents. Cluster analysis based on the frequency of specific keyword appearances was conducted and visualized. This information can serve as foundational data for the preemptive identification of accident causes and the development of strategies for collision prevention and response.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.533-541
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• 2022

An analysis of marine accidents that occurred in the last five years, revealed that 77.0 % of all grounding accidents and 66.1% of all marine casualties involved small vessels, which was a very high level relatively. The Mokpo Regional Maritime Safety Tribunal (Mokpo-KMST) inquired on 72 cases of marine accidents in 2021, of which 10 cases were grounding accidents. Furthermore, eight cases of grounding accidents occurred in small fishing vessels. This study analyzed eight cases of grounding accidents on small fishing vessels that inquired in the jurisdictional area of Mokpo-KMST in 2021. I found out that this grounding occurred in clear weather with good visibility (2-4 miles) and good sea conditions with a wave height of less than 1 meter. Furthermore, I found that the main causes of grounding were drowsy navigation due to fatigue, neglect of vigilance, neglect of checking ship's position, overconfidence in GPS plotter, and lack of understanding of chart symbols and tidal differences. To reduce grounding accidents of small fishing vessels, I suggested the following measures. First, crew members who have completed the able seafarer training course on bridge watchkeeping should assist to the master. Second, alarm systems to prevent drowsiness should be installed in the bridge. Third, the regulation should be prepared for the performance standards and updating GPS plotter. Finally, the skipper of small vessels should be trained periodically to be familiar with chart symbols and basic terrestrial navigation.