• Journal of The Geomorphological Association of Korea
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• v.25 no.4
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• pp.21-35
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• 2018

The distribution and size of sandy beaches along eastern Korea has a close relationship with the presence of granite rocks. In general, elongated and wide beaches with abundant sands are likely to develop along the coasts where granitic basic rocks comprise the dominant geology or where a large amount of sands are supplied by streams from inland granitic rocks. Small sandy beaches, in contrast, appear in non-granitic rocks (i.e., under sedimentary and/or metamorphic geology). Hence, large beaches are observed continuously along the shore of Gangwon-do, of which coasts consist predominantly of granitic geology. Such continuity declines from Samcheok city to Pohang city. The rock of Gyeonbuk-do is commonly known as sedimentary, deposited between the late Triassic and the early Tertiary Periods. Because few sands are supplied from the upstream areas, sandy beaches unlikely develop along the coasts of the province, only showing a sporadic, discontinuous distribution under Bulguksa granite, granitic gneiss, and some volcanic rocks. Erosion was rarely observed in the beaches where granitic rocks are distributed, whereas merely five beaches seemed to have undergone some level of erosion in non-granitic regions. This is presumably because a larger amount of sands than that which had been eroded away was replenished in areas under granitic geology, while under non-granitic geology having a deficit in sands, no large sandy beaches had formed at first.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1052-1060
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• 2023

The airborne radiation monitoring has been used in geophysics for more than forty years and now it also has its important role in emergency monitoring. The aircraft background and the cosmic gamma-rays contribute to the measured gamma spectrum on the aircraft board. This adverse effect should be eliminated before the data processing. The paper describes two semiparametric methods to estimate the full spectrum aircraft background and cosmic gamma-ray contribution from spectra measured at altitudes where terrestrial contribution is negligible. The methods only assume to know possible peak positions in spectra and their full width at half maximum, that can be easily obtained e.g. from terrestrial measurement. The methods were applied to real experimental data acquired on Mi-17 and Bell 412 helicopter boards. The IRIS airborne gamma-ray spectrometer, with 4×4 L NaI(Tl) crystals, produced by Pico Envirotec Inc., Canada, was used on helicopters' boards. To obtain valid estimate of the aircraft background and the cosmic contribution, the measurements over sea and large water areas were carried out. However, the satisfactory results over inland were also achieved comparing with those acquired over large water areas.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1341-1353
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• 2017

This study aimed to identify the aquatic and riparian factors associated with the presence/absence of the Eurasian otter in the Nakdong river basin, where the species is relatively more abundant than other otter species. Environmental factors and presence records were collected. Geographical Information System technology and chi-square test were used to compare environmental gradients in aquatic and riparian factors between presence and absence sites. Aquatic habitat attributes were evaluated with natural riverside sandbars and channel crossing artificial structures, the ratio of channel width to alluvial plain width, riverbed substrate, and flow diversity. Riverbank characteristics, bank materials, man-made embankment types, and land use/land cover of inland and riverside areas were selected as riparian habitat attributes. Compared to the aquatic attributes, riparian attributes were highly significant when assessing otter presence and absence sites, suggesting that conservation of suitable riparian areas to provide maternity and resting areas for otter species is essential in the Nakdong river basin. None of the aquatic attributes examined were statistically significant when evaluating otter presence or absence. These results indicate that the presence of suitable riparian area for resting and reproduction habitats is more critical to the presence of Eurasian otter than food availability in aquatic areas. To inform implementation of effective conservation actions, broad-scale factors, such as watershed attributes, would be needed to further assess habitat conditions of the Eurasian otter.

• Journal of the Korean Institute of Navigation
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• v.15 no.4
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• pp.41-58
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• 1991

The cooling degree days and the number of cooling days are used as important research materials not only in the field of design for building and cooling facilities but also in the government's establishment of energy policy. The purposes of this dissertation are to clarify the distribution of the cooling degree days and the number of cooling days by using the daily mean air temperature of 95 weather stations in Korea, and to show the distribution charts of the same cooling degree days and the same number of cooling days in order to help the practical uses of the materials. In cases of the base temperatures $24^{circ}C$, $25^{circ}C$, $26^{circ}C$, and $27^{circ}C$, the cooling degree days and the number of cooling days are shown in Table 5. The distribution charts of the same cooling degree days and the same number of cooling days are shown in Fig. 6 to Fig. 8 and Fig.9 to Fig. 11 respectively. As a result of this dissertation, Jeju Island and southern inland regions(especially Jeonju, Daegu, Gwangju) have a larger value than central regions and northern regions because of the influences of the terrain effect, and western coast regions have usually a larger value than eastern coast regions at the same latitude. The largest value appears in August of the year and the second in July, and the smallest in September. And southern inland area surrounded by Imshil, Goechang, and Boeun has a much smaller value than the other areas of its vicinity.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.96-104
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• 2010

During an artificial breeding as a part of restoration of the endangered Korean bitterling Acheilognathus signifer, a small number of individuals exhibiting oculocutaneous albinism were produced. We compared the pigmentation and morphology of normal and albinic bitterlings by histological examination of skin samples obtained from 10 regions on the body, fins, and eyes. There were no differences in morphometry and in general morphology of skin between them. In normal bitterlings, pigment cells were better developed in the dorsal region, the upper part of caudal peduncle region, the choroid-retinal epithelium and iris than in other areas. In the albinic bitterling, however, pigment cells were present only in three parts of the dorsal region, the caudal and dorsal fin, which had few melanin cells. Albinic bitterlings also displayed deficient pigmentation in the choroid-retina pigment epithelium and iris. Although they had different pigmentation aspects in distribution and development between normal and albinic bitterlings, melanin cells were mainly present in the dorsal regions of the skin and eyes where are exposed directly to light.

• Journal of Korea Water Resources Association
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• v.53 no.7
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• pp.521-531
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• 2020

The purpose of this study is to suggest a quantitative assessment of wetland damage considering the effects of topsoil erosion and deposition from rainfall. In the Cheoncheon Basin located upstream of the Yongdam Dam, 16 wetlands are located, but the lacustrine and small palustrine wetland were analyzed for possible damage to erosion and deposition. As a result of applying typhoon events in 2002 and 2003, the sediment load from the upper basin was the highest at 2.30% (22,548 ㎥) of low water capacity. The average sediment load in the mountain areas was found to be 0.03% of the low water capacity, and it was analyzed to be less damaging than the lacustrine with relatively large watershed. as a result of the model, the lacustrine wetland, where a large area is used as agricultural land, shows a high probability of sediment yield, so it is highly likely to damage the wetland by topsoil erosion.

• The Journal of Fisheries Business Administration
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• v.5 no.1
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• pp.9-42
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• 1974

Korea is a peninsular country surrounded by seas on three sides, and the fishing industry has carried out the service of suppling to the people with important anima protein. The distribution of fishery products has very complicated structures, because the production is in charge of small producers scattering along the coast all over the country, while consumpstion is made by separate homes in areas away from producing district. The relation between these two factors the structures make very complicated. The most typical and special structures of fishery distridution are distinguished in two, that is, one is landing market, the other is inland market. Landing markets have been monopolized by fishermen's cooperatives, providing with landing facilities and building sites. Fish markets played not only an important role in the landing, but distribution and price determination of catches by auction or tender. Inland markets are two types of wholesale market in consuming center, one is the terminal market for urban consumers, the other type is the local market for rural consumers. Fundamental functions of landing markets are gathering, assessment, and distribution functions. Gathering function is in charge of wholesaler in fishery cooperative. Gathering amounts are equal to gathering capacity of wholesaler and transact ability of licensed dealers as shown below model. Gathering amount=f.gathering capacity(=pre price.landing facility.account of wholesaler.distance of fishing ground.conveniency purchasing.home port)=fㆍ transact ability of licensed dealers≒f.population or port, and table 1 indicates these relationship. Assessment and distribution functions are in charge of licensed dealers in consumption side. Assessment function should bring the value in production activity through the auction between the cooperative seller and the licensed dealer as buyer. For fair trade transaction in auction, the free competition is supposed to be a prerequisite among the licensed dealers. The ideal condition for free competition is sameness in the scale of buying amount by licensed delaers, but it is almost impossible to attain its goal in actual marketing.

• Development and Reproduction
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• v.16 no.4
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• pp.321-327
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• 2012

Korean bullhead (Pseudobagrus fulvidraco) was collected from the Kum River areas of Kangkyung-eup, Nonsan city, Chungcheongnam-do, Korea, from April to June, 2012 and was fertilized in order to observe egg development and temperature-related cleavage rates and mitotic intervals (${\tau}_0$). The fertilized eggs were separative, demersal and light yellowish with $1.5{\pm}0.06mm$ in diameter, and did not contain oil globules. The first cleavage stages were 90 min, 80 min, 60 min and 50 min at $21^{\circ}C$, $24^{\circ}C$, $27^{\circ}C$ and $30^{\circ}C$, respectively. At higher temperatures, eggs developed faster and underwent further identical development. For Korean bullhead, ${\tau}_0$ were $33.4{\pm}2.08$ min at $21^{\circ}C$, $31.5{\pm}3.06$ min at $24^{\circ}C$, $28.1{\pm}2.11$ min at $27^{\circ}C$ and $26.4{\pm}3.35$ min at $30^{\circ}C$. There were strong negative correlations between the $\tau_0$ and water temperatures at all points studied (Y=-1.13X+58.15, $R^2$=0.98, n=30, where Y is ${\tau}_0$ and X is temperature). The results obtained in this work will be helpful for chromosome manipulation by use of cleavage frequency data and ${\tau}_0$ data in Korean bullhead.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.476-486
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• 2014

This study is aimed to understand the vertical distribution of fish in the daytime and nighttime using an acoustic survey in Yondam reservoir of Jeollabuk-do, and an acoustical backscattering strength of dominant species, bass (Micropterus salmoides) and a bluegill (Lepomis macrochirus), which are classified as the ecosystem disturbing species. The results showed that the fish school was distributed in the shallow areas of less than 10 m depth during the period of Aug. and Oct. where it had a strong thermocline, otherwise, it was distributed over 10-times density under stable water temperatures as $13^{\circ}C$ in Nov. There was no vertical patchiness difference between daytime and nighttime unlike the typical marine ecosystem. The dominant species were crucian carp, bluegill, bass. The hydroacoustic method can provide the spatial distribution and effective removal ways of the ecosystem disturbing species in inland fisheries.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.1-15
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• 2006

As the imports of foreign agricultural products are liberalized and the consumption of agricultural products declines, abandoned rice paddy fields continues to rise. However, such abandoned rice paddy fields has not been precisely surveyed yet. In this backdrop, a necessity to develop technology to utilize such abandoned rice paddy fields has emerged. Utilization of abandoned rice paddy fields as wetlands may be a good example. This study aimed to survey the current status and characteristics of wetlands created within abandoned rice paddy fields by selecting abandoned rice paddy fields throughout the nation and conducting field surveys on the sites that had transformed into wetlands. The abandoned rice paddy fields almost transformed into wetland and the types of wetlands transformed from abandoned rice paddy fields were mainly Inland/Moutain/Depression/Abandoned rice paddy fields/Marsh/Phragmites communis community and Inland/Moutain/Depression/Abandoned rice paddy fields/Swamp/Salix koreensis community. Abandoned rice paddy fields that had transformed into wetlands was depending heavily on waterways for water supply than other reservoirs and lakes do. Abandoned rice paddy fields transformed into wetlands was most observed in mountainous area. Abandoned rice paddy fields are because agricultural land is no longer profitable due to international and social changes and is not cultivated as government policy. Wetland period and dimension originated from abandoned rice paddy fields are very various and its surrounding land its mostly forest and the next largest follow roads and rural community. The abandoned rice paddy fields transformed into wetlands is mostly deserted currently. Despite their value as wetlands, no restoration and utilization efforts are made in Korea today. Therefore, it is imperative to conduct a precise current status survey on these areas and introduce management and restoration plans at the government level in the case of important habitats.