• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.638-645
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• 2013

For the efficient use of the insufficient frequency resources, a precise prediction of field strength based on various propagation environments should be set up to design of radio stations with reliable transmit power and service coverage. Therefore, many countries have tried to secure the propagation models suitable for their each geographical environments, and also, some models like BCAST were developed by Korea, but these models give the different results compared to measured values. In this paper, based on the measurements of DTV broadcasting services in domestic rural area, analysis and comparison of ITU-R P.1546 and BCAST models provide errors between measured and predicted values, and some points for improving SMI system has been proposed. As a result, P.1546 model provides the valid predicted data similar to measured data, but BCAST model has some problems of large deviation and higher prediction to measured data. In future, these problems and fading loss due to a forest or group of trees, and reflection loss due to a lake or sea need to be studied carefully.

• Korean Journal of Medicinal Crop Science
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• v.6 no.1
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• pp.51-56
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• 1998

This study was carried out to evaluate environmental and ecological characteristics of natural habitat for cultivation of Epimedium koreanum. Habitat of E. koreanum was the slope foot of mountain descending gradually toward mostly northwest from top of mountain with slope of $2{\sim}20%$ and the altitude ranged from 60 to 400m above the sea level. Some physiochemical characteristics of habitat soil were as follows: pH, $4.1{\sim}5.8$, organic matters content, $4.9{\sim}6.6%$ and cation exchange capacity, $14.8{\sim}34.3\;me/100g$ soil, respectively. Habitats were shaded by deciduous broad-leaved tree mainly, and compared with those of naked area, relative photon flux density was $3.5{\sim}13.1%$ and relative luminance was $3.3{\sim}11.9%$ due to shading. Air temperature of habitat under shade was $4.3{\sim}6.5^{\circ}C$ lower than that of naked area. Habitat soil temperature was lower than that of naked area but temperature range was smaller than that of naked area. E. koreanum plants were growing with semishading plants under shade of tree leaf. From investigation of natural characteristics of habitat, it was concluded that E. koreanum plant would grow at place with a little change in temperature and moisture of soil which was caused by shading and mulching with litterfall of broad-leaved tree.

• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.3
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• pp.64-78
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• 1992

In this study, elementary school students of both urban and rural areas as its subjects were asked to draw 'A beautiful landscape' by employing the perspective representation technique, i. e., the Perception Map, and to write down the elements comprising 'A beautiful landscape' in the questionnaire sheets. By doing so, an attempt was made 1) to analyze whether there are differences in perceiving 'A beautiful landscape' according to the differences of the environment in which they were brought up ; and, if there are differences. 2) to identify them ; and based on that , 3) to present basic data for evaluation on landscape, on its preference analysis and for Park Planning. The summary of this study is as follows ; 1) The main elements, elementary school students think, comprising 'A beautiful landscape' are 25 ones such as Sky(7), Sea(2), Water(2), Topography(5), Plants(5), Animals(3), School(1), Rural village(1). The natural elements showing a difference are ; Water fall in urban areas and School landscape in rural areas ; the artificial elements are ; City groups(Structures, Facilities, Necessities, Transportation means and Space) in urban areas and School groups in rural areas. Especially, in case of rural area children, they regard 'Trees' as an essential element to be 'A beautiful landscape' comparing to those in urban areas. 2) According to the analysis result on the correlation between the elements comprising a beautiful rural landscape and a beautiful ruban landscape, the correlation between boys and girls is high, showing the same trend with any difference. In comparison of urban areas with rural areas, there is no difference between natural elements, but in artificial elements(7 groups without family) the correlation is quite low, showing that all comprising elements are not the same between rural schools and cities, between schools within the same areas, and between schools of different areas. 3) In identifying the names of elements comprising 'A beautiful landscape', Back-Du Mountain and Sorak Mountain are shown the highest frequency in the category of mountains. In the names of trees and flowers, the elementary school children are thought to consider the kinds of trees and flowers they can see always at hand, i. e., those in their school ground where they spend most of their day time. 4) In the analysis of the numbers of comprising elements according to the responses in the questionnaire sheets and in the Perception Map, 'less than 10' is the most frequently counted number of comprising elements by individual students regardless of rural and urban differences. When the total frequency is divided by the number of students, the mean score is 6-7 without any differences between rural and urban areas, implying that there are no differences in the expression ability between urban and rural schools. 5) According to the result of classyfying and analysizing the landscape appeared on the Perception Map by similar elements and by similar scenes, 'A beautiful landscape' thought by elementary school children is defined not as a standardized form but as 11 types such as the landscape of fields, the landscape of a sea, the landscape of a rural village, a type where elements are assembled, the landscape of cities, the landscape of a school, the landscape coming out of a imagination, and other landscape. Both rural and urban children all consider the landscape of mountains and field and the landscape where several elements are assembled as a commonly beautiful one. Among the landscapes showing rural and urban differences, it can be analyzed that urban children regard the landscapes of cities, imagination, and waterfalls as something characteristic, while rural children regard the landscape of schools and rural villages as something characteristic.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.54-69
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• 2000

There are groundwater trouble by high-salinity yield inducing sea-water intrusion in Cheju Island. It is used groundwater-GIS(Well-lnfo) in the maintenance and management of groundwater in Cheju Island to grasp groundwater trouble area and cause of high-salinity yield. For 16 wells certain to yield high-salinity, we logged specific electrical conductivity(EC) and tried to get hold of freshwater and saltwater relationship. As result of distribution of $Cl^-$ by depth, it is showed up groundwater trouble by high-salinity yield in the east coastal area and the partly north coastal area. The reason of high-salinity groundwater yield are low-groundwater level by the structure of geology and low-hydraulic gradient etc. There is necessity for management to development and use of groundwater in the high-salinity area, special management area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.113-117
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• 2017

The purpose of this study was to evaluate the effects of rice cultivars (Hangaru, Seolgaeng, Dasan-1 and Anda) on the quality characteristics of rice beer. Hangaru and Seolgaeng which are soft rice varieties, had moisture contents that were 14.48% and 14.62% higher than those of Dasan-1 and Anda, respectively. Dasan-1 and Anda showed higher protein contents than those of the other two varieties. The amylose content of Hangaru was found to be 17.71% lower than that of the other varieties, whereas the reducing sugar content of Hangaru and Seolgaeng was higher than that of Dasan-1 and Anda. Hardness measurements for Hangaru and Seolgaeng were lower than those for Dasan-1 and Anda. Measurements of the alcohol content, pH and color of beers brewed using these rice cultivars revealed no significant difference among the cultivars. However, measurement results for bitterness showed that beers brewed with Hangaru and Seolgaeng had lower bitterness than did the beers brewed with Dasan-1 and Anda. The results of this study indicate that Hangaru and Seolgaeng can be considered as cultivars with brewing qualities suitable for rice beer.

• Journal of agricultural medicine and community health
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• v.21 no.1
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• pp.85-95
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• 1996

To examine the contamination in Ulsan coastal area, some heavy metal concentrations in sea water and Mytilus coruscus have been measured. Sea water samples were collected on April 6 in 1995 and Mytilus coruscus samples were collected on April 2 in 1995. Total number of sea water samples was 26 and that of Mytilus coruscus was 54. The sites where the samples collected were same in sea water and Mytilus coruscus. The method of analysis was atomic absorption spectrophotometer. The results indicated that the heavy metal concentrations of sea water were varied according to the sampling stations. The concentrations of cadmium, manganese, zinc in sea water collected in the coastal area near Mipo complex were higher than those of other coastal areas, and the concentrations of lead in sea water collected in the coastal area near petrochemical complex were higher than those of others. In general the concentrations of lead, zinc, copper in sea water were proportionate to those in Mytilus coruscus. The mean concentration rates of lead, cadmium, manganese in Mytilus coruscus inhabiting in Ulsan coastal area were similar, 1070, 1370 and 1300, respectively. The concentration rate of mercury was 80, the lowest value of other heavy metals, and that of copper was 6940, the highest value. Consequently it seems to be more desirable to use Mytilus coruscus as a sample to examine the contamination of coastal area than sea water.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.75-82
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• 2020

The Daehang-ri intertidal flat located the just outside of the Saemangeum dike has been reported to show new-developing flats. Based on the topographic surveys of 21 times from 2000 to 2016 by a leveling method every year, this site clearly shows variation of deposition/erosion in time and space. Deposition has consistently occurred at the rate of +3.75 cm per year at the area along the dike (Zone 1), and this tidal flat is expanding and prograding seaward. In the area of far from the dike (Zone 2), on the other hand, erosion prevails at the rate of -2.38 cm per year, and this zone tends to retreat landward. However, the erosional trend of Zone 2 has slightly slowed down since 2014. As a whole from 2000 to 2016, net deposition is recorded over 3.0 m at the upper beach and the area adjacent to the dike (Zone 1), while erosion up to 1.0 m in Zone 2. In conclusion, the results at the Daehang-ri intertidal flat clearly revealed that its topographic changes were induced by the artificial structures and water masses through its sluice gate. Counter-clockwise gyre newly created after the sea dikes construction probably results in relocating of sediment outside the dike 1 by transportation of materials eroded from the south to the north along the coast.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.279-286
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• 1998

The south-western part of Korea is situated in an unbalance of water supply and demand relating to the Keum, Mankyung, Dongjin and Youngsan River and their estuary reservoirs. For example, the Keum River estuary reservoir is discharging the larger amount of yearly runoff into the sea due to the small storage capacity, while Saemankeum estuary reservoir which is under construction, has the smaller runoff amount comparing with its storage capacity, And the downstream area of the Youngsan River, such as Youngkwang, Youngam are deficient in water due in larger demand and smaller supply. In order to solve the above unbalanced water supply and demand and also to improve the water use efficiency, the Hierarchical Operation Model for Multi-reservoir System(HOMMS) has been developed and applied to analyze the multi-reservoir operation assuming that the above reservoirs were linked each other. The result of this study shows that 2,148MCM of annual additional water requirement for agricultural and rural water demands are required in this region at 2011 of target year, and these demands can be resolved by diverting and reusing 1,913MCM of the released water from the estuary reservoirs into the sea.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.83-92
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• 1990

Experiment was conducted to establish the weed control system on the paddy fields by investigating species, period and amount of weeds in Gangwon province. Four locations were selected for these experiments : West plain area, Chunchon(74m above the sea level), mid-mountainous area, Hongchon(300 m), high alpine area, Hoengsong(450m), and east sea area, Myungju(14m). Weed emergence was investigated 6 times from 10 days after transplanting to 60 days with 10 days interval. From the experiments stated above, the results were summarized as follows ; The identity of weed species was small in grass family, but broad-leaf family was numerous. Also the dominant weed species was generally the perenial weeds. The weed emergence was initiated from 10 days after translanting. The amounts of weed counted the most in Chunchon. A large number of weeds were emerged between 30-60 days after transplanting in Chunchon and between 40-60 days after transplanting in Hongchon and Hoengsong. Among agronomic characteristics affected by weed emergence during rice development, plant height was decreased by 2~4cm, panicle number by 1.3~2.9, spikelet by 3.7~7.5, ripening rates 3.3~6.5%, and milled yield by 12~17%, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E1
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• pp.29-39
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• 2003

The 10-day interval basis measurements of precipitation samples at Yangyang, the rural and coastal area on the eastern coast of the Korea peninsula were accomplished for understanding the precipitation chemistry and the temporal variations of major ions September 1991 to February 1997. The precipitation was slightly acidic, and 37% of the samples in winter were pH less than 4.5. The concentrations of cations were found on the order $Na^+\;>\;{NH_4}^+\;>\;Ca^{2+}\;>\;Mg^{2+}\;>\;K^+$ and those of anions followed the pattern $Cl^-\;>\;{SO_4}^{2-}\;>\;{NO_3}^-$. Neglecting sea salt components, the major ions controlling precipitation chemistry were nss-${SO_4}^{2-}$ and ${NO_3}^-$ in anion and ${NH_4}^+$ and nss-$Ca^{2+}$ in cation. Concentrations of these ions were lower than those measured at urban sites in Korea, but were higher than those measured in Japan. Most of nss-${SO_4}^{2-}$ and ${NO_3}^-$ were neutralized by ammonia and calcium species, especially alkaline soil particles in spring and ammonia gas in other seasons. Considering also the annual value of ［nss -${SO_4}^{2-}$］/［${NO_3}^-$］ ratio of 2.62 and the neutralizing factors, ammonium sulphate compounds were dominant. Annual mean concentrations of these ions showed relatively small fluctuations, while larger seasonal variations were observed with higher levels in spring and winter. Precipitation amount, influence extent of acidic gases and alkaline particles long-range transported from China continent, and energy consumption pattern in each season might be able to explain this seasonal trend.sonal trend.