• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.485-491
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• 2014

In this paper, it is proposed that the effects of simulator sickness due to scene movement in ship handling simulator can be measured by using center of pressure (COP) and a simulator sickness questionnaire (SSQ). For experiments of simulator sickness, twelve participants are exposed to scenes movement from ship handling simulator according to three steps of sea states. During experiments, COPs for subjects are measured by force plate. After exposure to scenes movement, subjects describe their sickness symptoms by answering the SSQ. Throughput analysing the results of scene movement, SSQ, and COP, the relation between the simulator sickness and COP is investigated. It is suggested that formulations for SSQ score and COP with respect to sea state are obtained by the curve fitting technique, and the longitudinal COP can be used for measuring the simulator sickness.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.308-321
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• 2013

In order to understand the population dynamics of red tide dinoflagellate Noctiluca scintillans, we examined its hydrographical and bio-ecological characteristics at 19 to 20 stations of Gwangyang Bay during all four seasons from 2010 to 2012. During the 3-year period, N. scintillans was seasonally abundant during summer with water temperatures ranging from $15^{\circ}C$ to $22^{\circ}C$ and salinity ranging from 25 psu to 30 psu. On the other hand, N. scintillans population density significantly decreased in spring, fall and winter, although they were present even in lower temperatures (< $4^{\circ}C$). However, high water temperature (> $27^{\circ}C$) and low salinity (< 12 psu) led to the disappearance of N. scintillans population. Chl-a concentration in winter, spring and fall was positively correlated with N. scintillans population density, whereas the N. scintillans population was negatively correlated with Chl-a concentration in summer. This implies that densities of prey population such as diatoms are one of important contributing factor for maintaining abundance of N. scintillans in winter, spring and fall and for increasing abundance of N. scintillans in summer. During summer season, bio-accumulation of N. scintillans population by the wind from southwest is also considered to be a key factor in triggering the formation of large-scale blooms in Gwangyang Bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.3
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• pp.400-421
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• 2019

This study was conducted to find out the seasonal distribution characteristics of meiobenthic communities to understand the benthic ecosystem of Gwangyang Bay, one of the representative bays in the southern coast of Korea. The faunal sampling was conducted eight times seasonally at 20 stations from 2010 to 2011. Among the meiobenthic fauna that appeared during the study period, the nematodes and harpacticoids were the most dominant. In the summer of 2011, the lowest density ($13ind.10m^{-2}$) was seen at station 10 on the inner part of the bay. In the winter of 2011, the highest density ($3,109ind.10m^{-2}$) was seen at station 4 on the inner part of the bay. Although the trend of seasonal changes in density was not clear, the meiobenthic community was seen to be affected more by the environmental factors in each season. Particularly, while the density of the harpacticoids, a dominant faunal group, showed negative correlations with the organic content and average particle size in the summer sediments (p<0.05, p<0.01), the density of the nematodes showed no significant correlation with the environmental factors except with the winter average particle size and the bottom layer's water temperature. The density change of meiobenthos showed irregular changes in Gwangyang Bay, instead of a general trend showing a low density in winter due to low water temperature but an increased density in spring and summer when the water temperature rises and a decreased one again in fall. Considering such a seasonal trend, it seems that the benthic ecosystem of Gwangyang Bay is affected more by artificial environmental factors than by natural environmental ones.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.724-739
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• 2023

Located in the sea area between South Korea, North Korea, and China, the Yellow Sea plays an important role from a geopolitical perspective, and recently, as the use of marine space in the Yellow Sea is expanding, its social and economic values have been increasing further. In addition, owing to rapid climate changes, the need for joint response and cooperation between Korea and China is increasing in various fields, including changes in the marine environment and marine ecosystem and generation and movement of air pollutants. Accordingly, in this study, core topics were derived from research papers with the Yellow Sea as a keyword, and research trends to date were explored through author network analysis. As a specific research method, research papers related to the Yellow Sea published between 1984 and 2021 were extracted from the Web of Science database and were classified into four periods to derive core topics using topic modeling, a type of text mining. Furthermore, the influences of major research communities, researchers, and research institutes in the appropriate fields were identified through analyzing the author network, and their implications were presented. The analysis results indicated that the core topics of research papers on the Yellow Sea had changed over time, and differences existed in the influence (centrality) of key researchers. Finally, based on the results of this study, this study aims to identify research trends related to the Yellow Sea, major researchers, and research institutes and contribute to research cooperation between Korea and China regarding the Yellow Sea in the future.

• Ocean and Polar Research
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• v.35 no.3
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• pp.239-247
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• 2013

Digital image processing is a process to analyze a large volume of information on digital images. In this study, Artemia hatching rate was measured by automatically classifying and counting cysts and larvae based on color imaging data from cyst hatching experiments using an image processing technique. The Artemia hatching rate estimation consists of a series of processes; a step to convert the scanned image data to a binary image data, a process to detect objects and to extract their shape information in the converted image data, an analysis step to choose an optimal discriminant function, and a step to recognize and classify the objects using the function. The function to classify Artemia cysts and larvae is optimally estimated based on the classification performance using the areas and the plan-form factors of the detected objects. The hatching rate using the image data obtained under the different experimental conditions was estimated in the range of 34-48%. It was shown that the maximum difference is about 19.7% and the average root-mean squared difference is about 10.9% as the difference between the results using an automatic counting (this study) and a manual counting were compared. This technique can be applied to biological specimen analysis using similar imaging information.

• Animal Systematics, Evolution and Diversity
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• v.34 no.3
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• pp.143-151
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• 2018

A marine ciliate Amphisiella milnei (Kahl, 1932) $Horv{\acute{a}}th$, 1950 was discovered from the tidal pool of Baekdo Island, South Korea. The existence of extra cirri between leftmost frontal cirrus and buccal cirrus discriminates this species from its congeners. Its morphological features are described as follows: body size in vivo $110-130{\times}35-45{\mu}m$; elongate rectangular to elliptical in shape; two large and several small ring-shaped structures; yellowish cortical granules arranged irregularly on ventral side but longitudinally along dorsal kineties on dorsal side; 34-40 adoral membranelles, 3 frontal cirri, 1 buccal cirrus, 1 parabuccal cirrus, usually 2 extra cirri behind leftmost frontal cirrus, and 3 frontoventral cirri; amphisiellid median cirral row composed of 25-31 cirri with 27-36 left and 27-44 right marginal cirri; usually 5 transverse cirri and 2 pretransverse cirri with 7 dorsal kineties; two macronuclear nodules. In addition to, 18S rDNA sequence of A. milnei was analyzed to understand its phylogenetic relationship.

• Ocean and Polar Research
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• v.38 no.3
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• pp.209-224
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• 2016

The purpose of this study is to analyze research activities related to Antarctic science through a bibliographic study and to understand and evaluate the implications. This study is based on 78,445 articles which were retrieved from the Science Citation Index(SCI) database during the period 1998-2015. Through a quantitative analysis and a Social Network Analysis, we made several findings and drew out the implications. First, many countries, in general, have increased multi-national research cooperation in order to enhance research productivity. However, Korea's cooperative research activity is below the average level. Second, considering the 4 centrality indexes, which are derived from the SNA, Korea had a lower score in terms of centrality indexes. Based on these findings, Korea should formulate a more dynamic or proactive strategy in order to enhance its participation in international research cooperation efforts. Korea, the 10th country to build two or more research bases in Antarctica, should make greater efforts to bring the appropriate level of the phase.

• Ocean and Polar Research
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• v.35 no.1
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• pp.51-61
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• 2013

Two surveys were conducted in January 2006 and September 2007 with multibeam echosounder to investigate the dune shape, migration rate, and bedload transport rate using dune-tracking method on an offshore sand ridge at southern Gyeonggi Bay. The migration rates of dunes range from 1.8 $myr^{-1}$) to 56.0 $myr^{-1}$), at the upper northwestern side of sand ridge towards the southwest direction and from the center of the sand ridge towards the northeast direction respectively. Large (i.e. length 10-100 m) dunes show faster migration (0.3-23.4 $myr^{-1}$) ) than very large (i.e. length > 100 m) dunes because larger dunes have required a larger volume of sediments to be displaced. The decreases in dimensions and migration rates of dunes from the center of sand ridge to the lower part of southeastern side on the sand ridge can be ascribed to the decrease of sandy sediments availability, tidal currents with depth, and the coarsening of surface sediments from the crest of the sand ridge to the trough. Bedload transport rates on the basis of migration rates and dune dimensions decrease from 74.5 $m^2yr^{-1}$) at C transect to 35.6 $m^2yr^{-1}$) at R-02 transect.

• Ocean and Polar Research
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• v.35 no.2
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• pp.181-191
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• 2013

To investigate the occurrence of modern living planktonic foraminiferal species and their seasonal variations around Jeju Island, we conducted planktonic foraminiferal sampling at KIOST's regular sampling sites during 16 months. In total seven genus and 16 modern planktonic foraminiferal species were identified with six dominant species. Dominant species were Gloigerinoides sacculifer, Globigerinoides ruber, Globigerina bulloides, Noegloboquadrina dutertrei, Pulleniatina obliquiloculata, and Globorotalia inflata. Most of the species were characterized as being typical subtropical species and showed seasonal variations and/or intermittent occurrence from season to season. The occurrence of living foraminifera revealed a strong relationship with water temperature, but not with salinity. Species succession seems to occur along with water temperature changes. Some patch distribution and water temperature dependences appear to be significant since there is a high degree of variation in the occurrence patterns of species and standing stock. More detailed quantitative study is necessary to confirm the species diversity and seasonal variations of planktonic foraminifera and related ocean environmental changes.

• Ocean and Polar Research
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• v.35 no.2
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• pp.123-125
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• 2013

According to the Intergovernmental Panel on Climate Change (IPCC), ocean warming and acidification are accelerating as a result of the continuous increase in atmospheric $CO_2$. This may affect the function and structure of marine ecosystems. Recently, changes in marine environments/ecosystems have been observed (increase in SST, decrease in the pH of seawater, northward expansion of subtropical species, etc.) in Korean waters. However, we still don't understand well how climate change affects these changes and what can be expected in the future. In order to answer these questions with regard to Korean waters, the project named 'Assessment of the impact of climate change on marine ecosystems in the South Sea of Korea' has been supported for 5 years by the Ministry of Oceans and Fisheries and is scheduled to end in 2013. This project should provide valuable information on the current status of marine environments/ecosystems in the South Sea of Korea and help establish the methodology and observation/prediction systems to better understand and predict the impact of climate/marine environment changes on the structure and function of marine ecosystems. This special issue contains 5 research and a review articles that highlight the studies carried out during 2012-2013 through this project.