• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.109-117
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• 2001

The median encroachment accident model proposed in this paper is the first step to develop cost-effective criteria about installing facilities preventing traffic accidents by median encroachment. This model consists of expected annual number of median encroachment on roadway and conditional probability to collide with vehicles on opposite lane after encroachment. Expected encroachment number is related to traffic volume and quote from a study of Hutchinson & Kennedy(1966). The probability of vehicle collision is composed of assumed headway distribution of opposite directional vehicles (negative exponential distribution), driving time of encroaching vehicle and Gap & Gap acceptance model. By using expected accident number yielded from the presented model, it will be able to calculate the benefit of reduced accident and to analyze the cost of installing facilities. Therefore this will help develop cost-effective criteria of what, to install in the median.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.119-129
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• 1986

Disappearence of the trichlorfon (Dipterex) in the forest, following aerial to control Agelastica coerulea B., were studied by sampling deposits on slide glasses, soils, water, and leaves, and analysing with a gas chromatograph equipped with an electron capture detector. By analysing the amount remained on slide glasses, it was shown that the pesticide was adequately sprayed and nearly all deposit was lost in a day. The amount deposited under the tree was about 1/100 of the amount at an exposed site. Concentration of trichlorfon in creek water was 10 to 100 times as high as the acute toxic level to zooplankton for 6 to 24 hours, The rain could recontaminate the stream water up to the toxic level. Loss rate of trichlorfon from soils showed variations by sampling sites and was generally slower than from slide glasses. Amount deposited on leaves were less than the calculated or expected amount. The loss from leaves were similar to that from soil.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12A
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• pp.1229-1237
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• 2006

IEEE 802.11 has employed distributed coordination function (DCF) adopting carrier sense multiple access with collision avoidance (CSMA/CA). To effectively resolve collisions, DCF uses binary exponential backoff (BEB) algorithm with three parameters, i.e., backoff stage, backoff counter and contention window. If a collision occurs, stations involving in the collision increase their backoff stages by one and double their contention window sizes. However, DCF with BEB wastes wireless resource when there are many contending stations. Therefore, in this paper, to enhance the performance of wireless LAN, we propose binary negative-exponential backoff (BNEB) algorithm which maintains a maximum contention window size during collisions and reduces a contention window size to half after successful transmission of a frame without retransmissions. For IEEE 802.11, 802.11a and 802.11b standards, we also compare the performance of DCF with BEB to that with BNEB.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.42-54
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• 2018

This study is to establish the traffic volume-based warrants of left-turn lanes in unsignalized intersections based on a risk probability methodology. This study applied a risk probability of a potential rear-end collision between a left-turn vehicle and the immediately following through vehicle. With the shifted negative exponential model and the compound probability theorem, the risk probability can be expressed as the function of directional volumes, opposing volumes and the percentage of left-turns for a two-lane and four-land highway, respectively. The warrants of installing left-turn lanes on unsignalized intersections were developed with the risk probability. The warrants define the total approaching and opposing volumes to encourage a left-turn lane as a function of operating speed, percentage of left-turn, and number of lanes.

• Journal of Life Science
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• v.20 no.2
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• pp.219-224
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• 2010

This study was carried out to develop the breeding and cultivation of Allium grayi by investigating its natural habitats in Korea. The number of sunny, half-shady, and shady natural habitats were 194 (64.0%), 96 (31.7%), and 13 (4.3%), respectively. Natural habitats included upland (51.2%), Buddhist temple (18.8%), mountain (11.6%), roadside (7.9%), river (5.9%), paddy field (2.3%), and seashore (2.3%). Natural habitats ranged widely in all areas between $33^{\circ}N{\sim}38^{\circ}N$ and $126^{\circ}E{\sim}130^{\circ}E$. Self-generation patterns included growing spontaneously with a 1~10m distance between plants, and there were 3~5 bulbils around each bulb. The sprout stage began in September and continued until March of next year in natural habitats. The bolting period was May, with the following three patterns: tuber (59.2%), flower and tuber (24.7%), and flower (16.1%).

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.2
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• pp.41-46
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• 1989

Rhododendron micranthum grown over the area of Kyoung Puck, Kang Weon Province is showy and very attractive evergreen broad-leaned shrub of shade resistance. This shrub is considered very useful for exploiting as a garden plant. Environments, growth characteristics and vegetation association in the wild habitat and in the garden planted with this shrub, were investigated to find out some appropriate means of propagation and cultivation of this shrub. The results thus obtained were stated as follows ; 1. Light intensity for the native habitat ranged in the proximity of 9%. The most abundant stand of this shrub occurred in the northen side of mountains, while still some plants were found in the eastern sides also. 2. Soil of the native habitat was acidic (pH 4.4) and infertility. 3. Average elevation of the native habitat was shown to be 230m above the sea level. 4. The plant of the native habitat showed an average of 3.9 new shoots per branch, whereas that of the garden planted (light intensity 100%) showed 1.2, 5% of an average was for sun-burn leaves were noted, while garden Plants(light intensity 100%) showed 90% of them. 5. Other tree species associated with Rhododendron micrathum in the native habitat were primarily Pinus densiflora and secondarily Sorbus alnifolia, hemerocallis aurautiaca, Rubus crataegifolius, and Salix hulteni. 6. Vegetation rate of plant habitats in the Rhododendron growing area was observed to be 0 to 80% involving 27 to 50 species of associated trees in the vegetation for the 10${\times}$10m quadrat area.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.68-68
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• 2002

아열대성 식물 4종 (문주란, Crinum asiaticum var. japonicum; 박달목서, Osmanthus insularis; 죽절초, Chloranthus glaber; 파초일엽, Asplenium antiquum)을 대상으로 자연 환경요인의 변화에 따른 엽록소형광을 분석하여 이들 식물의 활력도를 검토하였다. 여름철 일변화에 있어서 양지에 자라는 문주란과 박달목서는 Fv/Fm이 새벽과 밤에는 0.80~0.83 범위의 높은 값을 보이지만, 낮시간에는 0.65~0.73으로 낮았다. 1-qN과 1-qP도 낮시간에 크게 낮아졌다. 음지에 자라는 죽절초와 파초일엽의 Fv/Fm은 높아서 0.83~0.85 범위를 유지하였으며 일변화적 특성은 관찰되지 않았다. 1-qP의 변화는 거의 관찰되지 않았으나 1-qN이 낮시간에 다소 감소하는 경향을 보여주었다. 죽절초와 파초일엽에서는 광억제가 거의 일어나지 않으나 문주란과 박달목서에서는 낮시간의 고광에 의한 광억제가 나타난다. 하지만 여기에너지의 일부를 열의 형태로 방출하여 광피해를 완화시키고 있는 것으로 보인다. 겨울철에는 Fv/Fm이 모든 종에서 0.8 이하의 값을 나타내었는데, 특히 문주란의 Fv/Fm 값은 다른 3종 보다 더 낮았다. 그리고 모든 종에서 일변화적인 특성은 관찰되지 않았다. 문주란의 1-qN은 낮시간에 다소 감소하였지만, 나머지 3종의 식물은 높은 값을 나타내었다. 그리고 l-qP는 문주란과 박달목서에서는 낮시간에 0.6 범위로 낮아졌다. 이는 종에 따라 차이가 있지만 겨울철 저온의 영향을 받은 결과로 보인다. 한편, 여름철 문주란과 박달목서의 O-J-I-P곡선은 거의 유사하며 낮에 뚜렷하게 낮았고, 죽절초와 파초일엽에서는 일변화적 특성은 두드러지지 않았다. 그리고 P $I_{NO}$ 와 SF $I_{NO}$ 가 죽절초를 제외한 3종에서 여름철 낮시간에 증가하였다. 겨울철의 O-J-I-P곡선은 모든 종에서 낮시간에 다소 낮아지지만 큰 변화는 없었다. 그리고, 문주란, 박달목서, 파초일엽에서 $\psi$o/(1-$\psi$o)가 낮시간에 다소 증가하였다. 이로부터 P $I_{NO}$ , SF $I_{NO}$ , $\psi$o/(1-$\psi$o)등의 변수는 식물의 활력도를 검정하는 지표로 활용될 가능성이 높다고 할 수 있다.

• The Journal of Korean Medicine
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• v.31 no.5
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• pp.112-123
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• 2010

Objectives: Three yin-tonifying formulae (Ssanghwa-tang, Yukmijihwang-tang and Jaeumganghwa-tang) were applied to investigate their immunological activities on antigen (Ag)-specific or Ag-non-specific immune responses in the murine macrophage cell line (RAW 264.7) and in ovalbumin (OVA)-immunized mice. Methods: This study was carried out in nitricoxide (NO) synthesis in RAW 264.7 cells and cellular proliferation in mouse splenocytes in association with three herbal formulas. C57BL/6 mice were immunized intraperitoneally with OVA/aluminum ($100\;{\mu}g/200\;{\mu}g$/mouse) on days 1, 8, and 15. Three herbal formulas were administrated to mice orally for 3 weeks from day 1. On day 22, OVA-, lipopolysaccharide (LPS)-, and concanavalin A (Con A)-stimulated splenocyte proliferation and antibodies (OVA-specific antibodies of the IgG, IgG1, and total IgM classes) in plasma were measured. Results: All three yin-tonifying formulas significantly enhanced cellular proliferation by LPS and Con A in splenocytes from OVA-immunized mice (p<0.001). Also, these herbal formulas all significantly enhanced plasma OVA-specific IgG, IgG1, and total IgM levels compared with the OVA/Alum group. Conclusion: These results suggested that the three yin-tonifying formulae could be used as stimulators of immune response.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.289-295
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• 2005

This paper reports on the dendrochronological investigation of tree ring growth of Pinus densiflora in the Gyeongbuk region. Tree ring growth was analysed using basic statistical value and correlation analysis to evaluate the relative contribution of climatic factors. Ta extract age-related trends and nonclimatic signals, each measurement series was standardized using a negative exponential growth function. In the Gyeongbuk region, tree ring growth was positively correlated with the current year in February, March and April, January, February, and March precipitation showed a positive correlation with the current growth year. This suggests that climatic factors (monthly average temperature, precipitation) limit breaking of dormancy and promotion of growth of Pinus densiflora in the Gyeongbuk region.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.1
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• pp.1-11
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• 2012

Human thermal sensation based on a human energy balance model was analyzed in the study areas, the Changwon and Nanaimo sites, on clear days during thesummer of 2009. The climatic input data were air temperature, relative humidity, wind speed and solar and terrestrial radiation. The most effective factors for human thermal sensation were direct beam solar radiation, building view factor and wind speed. Shaded locations had much lower thermal sensation, slightly warm, than sunny locations, very hot. Also, narrow streets in the Nanaimo site had higher thermal sensation than open spaces because of greater reflected solar radiation and terrestrial radiation from their surrounding buildings. Calm wind speed also produced much higher thermal sensation, which reduced sensible and latent heat loss from the human body. By adopting climatic factors into landscape architecture, the human thermal sensation analysis method promises to help create thermally comfortable outdoor areas. The method can also be used for urban heat island modification and climate change studies.