• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.221-234
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• 2017

The Baengnokdam, the summit crater of Mt. Halla, is one of the representative geosites of World Natural Heritage and Global Geopark in Jeju Island. The crater is marked by two distinctive volcanic lithofacies that comprise: 1) a trachytic lava dome to the west of the crater and 2) trachybasaltic lava flow units covering the gentle eastern slope of the mountain. This study focuses on understanding the formative process of this peculiar volcanic lithofacies association at the summit of Mt. Halla through field observation and optically stimulated luminescence (OSL) dating of the sediments underlying the craterforming volcanics. The trachyte dome to the west of the crater is subdivided into 3 facies units that include: 1) the trachyte breccias originating from initial dome collapse, 2) the trachyte lava-flow unit and 3) the domal main body. On the other side, the trachybasalt is subdivided into 2 facies units that include: 1) the spatter and scoria deposit from the early explosive eruption and 2) lava-flow unit from the later effusion eruption. Quartz OSL dating on the sediments underlying the trachyte breccias and the trachybasaltic lava-flow unit reveals ages of ca. 37 ka and ca. 21 ka, respectively. The results point toward that the Baengnokdam summit crater was formed by eruption of trachybasaltic magma at about 19~21 ka after the trachyte dome formed later than 37 ka.

• Ocean and Polar Research
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• v.43 no.4
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• pp.307-320
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• 2021

Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

• Korean Journal of Ichthyology
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• v.32 no.1
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• pp.21-25
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• 2020

A single specimen of Strophidon sathete (1,302 mm in total length), belonging to the family Muraenidae, was collected in a danish seine off the southern coast of Jejudo Island in April, 2019 for the first time. It was characterized by having unpatterned coloration and thin body, snout slightly rounded, three superorbital pores, four infraobital pores, and six mandibular pores. This species is distinguishable from morphologically similar Gymnothorax albimarginatus inhabiting Korean waters by having all fins dark (vs. fins dark posteriorly with white margin for latter), body depth 1.8~3.1% in total length (vs. 3.2~5.7%), and no dark band on head in less than 50~70 cm (vs. exist). We add Strophidon sathete to the Korean fish fauna and propose a new Korean name, "Ga-neun-gom-chi" for the species because the body is relatively thinner than other similar moray species (G. albimarginatus) in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.294-302
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• 2019

As a series of fundamental researches on the development of an automatic identification monitoring system for fishing gear. Firstly, the study on the installation method of automated identification buoy for the coastal improvement net fishing net with many loss problems on the west coast was carried out. Secondly, the study was conducted find out how to install an automatic identification buoy for coastal gill net which has the highest loss rate among the fisheries. GPS for fishing was used six times in the coastal waters around Seogwipo city in Jeju Island to determine the developmental status and underwater behavior to conduct a field survey. Next, a questionnaire was administered in parallel on the type of loss and the quantity and location of fishing gear to be developed and the water transmitter. In the field experiment, the data collection was possible from a minimum of 13 hours, ten minutes to a maximum of 20 hours and ten minutes using GPS, identifying the development status and underwater behavior of the coastal gillnet fishing gear. The result of the survey showed that the loss of coastal net fishing gear was in the following order: net (27.3%), full fishing gear (24.2%), buoys, and anchors (18.2%). The causes were active algae (50.0%), fish catches (33.3%) and natural disasters (12.5%). To solve this problem, the installation method is to attach one and two electronic buoys to top of each end of the fishing gear, and one underwater transmitter at both ends of the float line connected to the anchor. By identifying and managing abnormal conditions such as damage or loss of fishing gear due to external factors such as potent algae and cutting of fishing gear, loss of fishing gear can be reduced. If the lost fishing gear is found, it will be efficiently collected.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.2
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• pp.67-76
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• 2010

This study examined and analyzed uses, transformations, changes of plane and arrangement, and changes of space structure of housing components with traditional folk houses located at Kyideok village, Hanrim-eup, Jeju, and the results of the study can be summarized as follows. First, the exposure of arrangement of folk houses at Kyideok village, Jeju was evenly distributed to the east, the southeast, the northeast and the west in order and it was little different from the use of sunshine conditions by placing the main room on the south in traditional houses of land areas. Second, the space structure of inner room before transformation was divided into seven types. 3-room type was classified into "Sangbang-centered three-room type" and "nanggan-centered three-room type", 4-room type into "four-room type with inner access to warehouse", "four-room type with outer access to warehouse", "kitchen-divided four-room type", "four-room type with two kitchens", "four- room type with nanggan at the right back". Third, according to types of change in arrangement type, the first is new annex addition to existing inner room, the second is the removal of existing annexes including outer room, the third is the extension of inner room size without new construction of annex, the fourth is new construction of annex with new plane form after removal of existing annex, the fifth is no change in arrangement of inner room, outer room, stable, warehouse, etc. Fourth, transformation of space components led to changes of space structure as well as those of plane form. Changes of space structure were divided into reduction type of circulation to specific factors, negligence type without using increased space factor, and addition type having various circulations through the increase of convenience space.

• Korean Journal of Remote Sensing
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• v.21 no.6
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• pp.469-482
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• 2005

China Coastal Waters (CCW) usually appears in the seas surrounding Jeju Island annually(June to October) and is very pronounced in August. Generally, low-salinity water appears to the western seas of Jeju Island from June through October and gradually propagates to the eastern seas, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the variance in SLAs and SSTs was $95.01\%$(the first mode to third mode) and $98.09\%$(the first mode), respectively. The PSD of the western waters for the first mode of EOF analysis of SLAs was stronger than that of the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the seas to the west and east of Jeju Island), with a period of approximately 260 days.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.564-568
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• 2009

The principal objective of this study was to determine and characterize the food resources and foraging sites of Pacific Reef Herons bred in Aewol-eup, Jeju Island, during Feb. 2005 ~ Aug. 2005. The food resources of Pacific Reef Herons were identified as comprising 21 individuals of 5 species, and these identifications were verified as follows: 38.1% of Tridentoger obscurus(n=8), 19.0% of Ennedpterygius etheostomus(n=4), and 14.3% of Engraulis japonica(n=3). The sizes of the food resources were measured as follows: total $58.29{\pm}5.17mm$(n=19), T. obscurus was $67.49{\pm}4.91mm$(n=8), E. etheostomus was $43.98{\pm}3.50mm$(n=4), and E. japonica was $22.77{\pm}1.17mm$. The semi-digested foods were confirmed as Paralichthys olivaceus and Sebastes inermis. The primary foraging sites were 7.4km(Oedocheon) east, to 6.6km(Geumseongcheon) west of the Aewol breeding area.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.3
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• pp.256-271
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• 2016

The source and transport of the severe Asian dust event (ADE) recently observed in the Korean peninsula were analyzed based on observations (surface weather charts and satellite data) and modeling study (WRF-CMAQ modeling systems). The ADE occurred on 20-21 March 2010 in South Korea with very high $PM_{10}$ concentrations (up to approximately $3,000{\mu}g/m^3$ in Daegu and Jeju). The dominant meteorological conditions affecting the dust outbreak and transport processes were found to be associated with the two synoptic features: (1) strong airflows (i.e., westerlies) induced by a strong pressure gradient resulting from a dense isobar pattern (west-high and east-low) between Tuva Republic and Mongolia and (2) a rapid movement of the strong westerlies merged with airflows generated near Gobi Desert and Inner Mongolia. The merged strong westerlies with a low pressure played a pivotal role in the huge amount of AD and its transport height of 5-8 km. The time and location of dust emissions calculated in the source regions were similar to those observed in the weather charts and satellite image. The ADE simulation mostly showed agreement in the patterns and the concentration levels of modeled dust (including $PM_{10}$) with those of the observations.

• 한국해양학회지
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• v.18 no.1
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• pp.64-72
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• 1983

A series of sheps-of-opportunity sea sryface temperature (SST) measurement beween Jeju and Wando during a period from December 1979 through June 1981 produced following results. 1. A sihnificantly warm water appeared south of Chuja Island and Cheongsan Island during Island. It is suggested that this water represents a current entering the Jeju Strait from the west. Direction of this currint in other seasons is not certain. 2. Coastal waters were found north of the Cheongsan Island and Bogil Islhnd throughout the measurement period. In February these waters sometimes reached as far as Chuja Island to south. 3. Frequently thermal fronts were observed near the Chuja Island and the Cheongsan Island. 4. In summer cold waters appeared north of the Chuja Island and Changsu Island. Intrusion of cold bottom water from offshore and its subsequent vertical mixing due to strong tidal current are probably reponsible for this appearance. 5. Cold waters also appeared locally around islands and in ghe Jeju Harbor in spring and summer. 6. North-south SST difference reached 8-9$^{\circ}C$ in winter which is the annual maximum. 7. Annual range of SST varies from 12-14$^{\circ}C$ in the central part of the Jeju Strait to 16-20$^{\circ}C$ in coastal waters to north. The highest SST appeared everywhere in September but the lowest one did not appesr in the same month of year.

• Journal of East-West Nursing Research
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• v.13 no.1
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• pp.13-21
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• 2007

Purpose: This study was to investigate the knowledge and attitude of nurses who play a significant role in taking care of the aged. Method: The research surveyed 132 nurses working at care facilities for the aged in Seoul, Gyeonggi province, Daejeon, and Jeju.. Measures were knowledge scale and attitude scale. Collected data were analyzed using SPSS/WIN 12.0. Result: First, the mean of knowledge of nurses was 16.45 (0.463), which was high in the knowledge (66%). The mean of attitude was 2.71 (0.764), which was in the neutral range. Second, There was no correlations between the knowledge and the attitude of nurses toward the aged. Third, (1) The degree of knowledge was significantly different according to age, educational backgrounds, clinical experiences, hospitals they work for, how they acquired the knowledge, and whether they took the GNP course. (2) The degree of attitude was significantly different according to age, departments they work for, how they acquired the knowledge, and whether they took the GNP course. Conclusion: As a result, this study could show that nurses are taking a greater interest in the aged, which reflects the social interest in the aged following the rapid growth of the aged population.