• Journal of Korean Society of Transportation
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• v.24 no.2 s.88
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• pp.127-137
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• 2006

This Paper Presents a novel incident detection method for using the speed-density difference between detectors. When a incident is happened the downstream traffic condition is mostly lower speed and higher density and the upstream is higher speed and lower density In respect of such characteristics, we can suggest a method for detecting an incident based on the speed-density information provided from detectors. The incident detection method is tested by using the accident data collected from the Cheonan-Nonsan Highway. The results show that suck an incident detection method can analyze the position of accident by comparing the speed-density difference between detectors. The work described in this paper is only at on early stage, in the sense that there are several areas to be further investigated in application of this method. such as setting a critical value for judging the incident. a level of accident wave, a varying Pattern between the incident locations and detectors, etc.

• Water for future
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• v.28 no.4
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• pp.147-154
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• 1995

Scour characteristics of noncohesive bed materials at the downstream of free-falling jet were analyzed through hydraulic experiments. It was assumed that the downstream had no special energy dissipators. Flow characteristics of free falling jet from rectangular section were studied, and scour characteristics with and without mounds, which were generated at the downstream of the scour hole, were comparatively analyzed for various bed materials, discharges and tailwater depths. Not only the equilibrium scour depth but also the height of mound could be expressed as a function of densimetric Froude number. Densimetric Froude number had closer relationship with the equilibrium dimensionless scour depth than other dimensionless parameters. It was suggested that the mound effects should be considered at the design stage of bed protection works.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.583-599
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• 2022

According to the discussion on the low-density economy in OECD industrial growth in remote area has played a central role in the members'economic recovery from the financial crisis in the mid-2000s. Based on the OECD's low-density economy this study examines the phenomena and spatial characteristics of industrial growth in peripheral areas of Korea. The growth of industries in the peripheral areas shows a similar growth characteristics as cases in the OECD members. Various manufacturing and service sectors as well as traditional sectors such as agriculture, forestry and fishing have grown in the peripheral areas since the mid-2000s. Firms in the peripheral areas form various cooperative networks to overcome the unfavorable regional conditions. The growth of new industries shows the possibility of path-dependent development in the periphery. Based on the results, implications on the policies for supporting the diversification of regional industries, setting flexible regional boundaries for policies, and linking policy sectors are derived.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.128-128
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• 2021

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.35-35
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• 2019

현호색속은 양귀비과에 속하는 분류군으로서 전 세계에 약 450분류군이 분포하며 한국에는 25분류군이 분포한다. 20분류군의 한국산 현호색속 식물을 대상으로 화부 형태, 밀선의 형태, 밀선의 부착 위치를 비교 분석하였다. 현호색속 식물의 꽃은 좌우대칭하며 외화판의 거(spur)에 위치한 밀선을 갖는데 밀선의 위치, 형태 등은 현호색속의 분류체계를 반영하는 중요한 형질로 판단된다. 관찰결과 현호색절과 가는괴불주머니절의 밀선은 거(spur)의 1/3~2/3 정도 까지 신장되며 신장부는 매우 가늘지만 선단부에서는 다소 부푼 후 뾰족해지고 아래쪽으로 굽으며 분비조직이 위치하고 있는 부분은 녹색, 신장부는 횐색을 띠었다. 들현호색절에서는 거(spur)의 중간 정도에 위치한다. 기부는 두껍고 화색과 같은색을 띠지만 끝부분은 가늘고 굽지 않으며 흰색을 띤다. 자주괴불주머니절의 밀선은 거의 신장되지 않고 주걱형이며 노란색을 띠었다. 산괴불주머니절에서는 거(spur)의 3/4까지 신장되며 선단부는 뾰족하고 녹색을 띠며 아래로 굽는다. 밀선의 형태는 거(spur)의 형태와 관련이 있다. 거(spur)가 주머니처럼 부푸는 절에서 밀선분비조직의 뚜렷한 발달이 관찰되고 거(spur) 안에 분비된 화밀을 저장한다. 비록 현호색절과 산괴불주머니절이 서로 밀접한 계통을 갖지는 않지만 이들이 공유하는 밀선의 형태는 거(spur) 형태의 유사성에서 기인한 것으로 보인다. 한국산 현호색속 밀선의 형질진화 분석을 위하여 mesquite을 이용하여 ancestral reconstruction를 수행하였다. 밀선의 형질진화는 한국산 현호색속 5절의 계통진화를 반영하였다. 현호색속의 화부형질은 매우 복잡하고 다양한 방향으로 진화한 것으로 보이며 이를 이해하기 위해서는 다양한 화부형질의 종합적인 검토가 필요하다. 이번 연구에서 확인된 화부구조와 분비조직의 형질은 현호색속의 계통진화를 잘 반영하고 있었으며 향후 분비조직의 해부형질, 미세형질 등의 추가연구를 통하여 현호색속의 계통연구를 위한 새로운 분류학적 가치를 제공할 수 있을 것이다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.417-417
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• 2010

작은 직경의 외부 전극 형광램프와 냉음극 형광램프는 LCD-TV의 광원으로 사용하고 있다. 교류 전압으로 구동되는 외부전극 형광램프와 교류 및 직류 전압으로 구동되는 냉음극 형광램프에서 광 방출 신호를 관측하였다. 이러한 빛은 양광주의 고전압부에서 접지부로 $10^5-10^6\;m/s$의 속도로 전파한다. 램프에서 방출된 광이 양광주를 따라 전파하는 현상은 일반 형광등과 네온싸인관에서도 동일하게 관측된다. 이러한 빛의 전파 현상은 지난 70년의 형광 램프 역사상 처음 관측되었다. 양광주 영역의 플라즈마는 높은 전압과 수 십 kHz가 인가되는 전극부에서 발생한 고밀도 플라즈마의 확산으로 생성된다. 고전압이 인가된 전극부에서 발생한 고밀도의 플라즈마는 인가되어지는 구동 주파수에 해당하는 섭동으로 작용하여 플라즈마 파동으로 양광주 영역으로 전파된다. 이러한 플라즈마 파동은 고밀도 전극부에서 저밀도 양광주 영역으로 플라즈마 밀도의 차이에 의하여 된다. 이때 파동의 전파 속도는 관 전류에 따라 달라진다. 타운젠트 방전 이전의 저 전류일 때는 ${\sim}10^5\;m/s$이며, 타운젠트 방전 이후 글로우 방전에서의 전파 속도는 ${\sim}10^6\;m/s$로 증가한다. 또한 타운젠트 방전 이전의 저 전류에서는 파동이 감쇠하는 경향을 보이며, 고 전류에서의 파동의 감쇠는 매우 작다. 관측된 광신호의 결과로부터 전파되는 파동의 원인은 플라즈마 확산에 의한 밀도의 차이에 의한 것으로 해석된다. 즉, 수 십 kHz의 구동 주파수를 갖는 플라즈마 파동이 양광주의 플라즈마 밀도 구배에 의하여 전파된다. 이러한 파동은 높은 전압이 인가되는 전극부에서 낮은 전압부로 향하는 조류의 흐름과 같이 나타난다.

• Korean Journal of Environment and Ecology
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• v.3 no.1
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• pp.42-50
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• 1989

A valley and a ridge forest in Mt. Gaya area was studied to investigate forest structure in relation to altitude and part of slope. Sixty-three quadrats were set up in the valley forest along altitude of 600m to 1,000m and part of slope, and thirty-eight quadrats were set up in the ridge forest along altitude of 700m to 1,430m. According to the importance values, the valley forest was Quercus mongolica-Lespedeza maximowiczii community and the ridge forest was Pinus densiflora, Quercus mongolica-Rhododendron mucronulatum community. Similarity index between the valley forest community and the ridge forest community was 37.2%. Shannon's species diversities of the valley forest community and the ridge forest community were 1.3402 and 1.0098, respectively. According to importance values by crown stories and DCA ordination, successional trends of tree species may be from Pinus densiflora and Pinus koraiensis through Quercus mongolica to Quercus serrata and Carpinus laxiflora. As going from the lower part to upper part of the slope in the valley forest, the importance values of Quercus mongolica, Quercus aliena, Rhododendron mucronulatum and Lespedeza maximowiczii increased while those of Carpinus laxiflora and Fraxinus rhynchophylla decreased. With increasing elevation in the valley and ridge forest, the importance value of Pinus densiflora decreased while that of Quercus mongolica increased. In the valley forest, densities of canopy and shrubstratum increased as increasing elevation, and the number of species and species diversity decreased as increasing elevation and going from the lower part to the upper of slope. The range of similarity indices between parts of the slope, and the elevation belts of 100m in the valley forest were 66.6-69.2 and 25.9-79.8%, respectively. In the ridge forest, density and basal area of canopy tended to decreased as increasing elevation, and the range of similarity indices between elevation belts of 100m was 27.9-98.2%.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.59-67
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• 1994

Differences in physicochemical characteristics of sediment and changes in density, height and dry matter of shoots along different water depths were investigated in the stands of Zizania latifolza populations of the littoral zone of Lake Paltangho, Korea. Any significant differences in sediment chemistry were not found along water depth, although sand content decreased slightly with increasing depth. Shoot density of Zizania latqolia decreased with increasing water depth. In shallower water, many of the short shoots died in the early growth stages. The morphology of shoots was taller and heavier in deeper water. The distributions of shoot heights became negatively skewed and leptokurtic as plants grew, and these changes occurred in the earlier growth stages in deeper water. The standing crop of shoots increased with increasing water depth. These results suggest that Zizania lattfolia has a growth strategy for adjustment to deep water through decreasing shoot density and increasing height.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.8 s.239
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• pp.940-947
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• 2005

An immersed boundary method for simulation of density-stratified flows has been developed and applied to computation of viscous flows past three different types of obstacle under table density stratification, namely laminar flows past a vertical barrier, a cosine hill, and a sphere, respectively. Density forcing is introduced on the body surface or inside the body. Significant changes in flow characteristics are observed depending on Fr. The numerical results are in good agreement with other authors' experimental and numerical results currently available, and shed light on computation of density-stratified flows in complex geometries.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.287-293
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• 2008

Density is used as the measure of effectiveness within the ramp junction influence area suggested in the KHCM 2005 in the LOS analysis of the ramp junction, and also density predictive models suggested in the KHCM 2005 is constructed based on the expressway with the speed limit of 100km/h or 110km/h in Korea. So, the density predictive models suggested in the KHCM 2005 are needed to verify if the models could be applied to the urban freeway with the speed limit of 80km/h or less, because the speed limits on most of the urban freeways in Korea are 80km/h or less. The purpose in this study is to construct and verify the appropriate density predictive model within the on-ramp merge influence area of the urban freeway by comparing with the USHCM 2000 and KHCM 2005 models.