• International Journal of Highway Engineering
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• v.13 no.1
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• pp.97-105
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• 2011

This paper presents how one can investigate the effects on crash occurrence of freeway geometric design elements including the horizontal, vertical alignment and road environment. At present, the available research results for the most part involve geometric data analysis that are obtained along a relatively long section of freeway, and, because of the long section's diverse geometric conditions, the results tend to miss the specific local geometric impacts on vehicle crashes. In this regard, this research attempts to establish vehicle crash models based on a set of freeway geometric patterns whose crash generating characteristics are identical because they are homogeneous in terms of producing the same vehicle operating speeds, and subsequently their actual relationships are described by providing statistical analysis made in this research. Also each standard is comprised of part of straight, curve and continuous curve. This research has revealed that each type of model has different relation between accident and geometry structure. This research results should be useful for doing more reasonable highway designs and safety audit analysis.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.141-153
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• 2010

The study is about the development of operating speed prediction models aimed for an evaluation of design consistency of four lane rural roads. The main differences of this study relative to previous research are the method of data collection and classification of road alignments. The previous studies collected speed data at several points in the horizontal curve and approaching tangent. This method of collection is based on the assumption that acceleration and deceleration only occurs at horizontal tangents and the speed is kept constant at horizontal curves. However, this assumption leads to an unreliable speed estimation, so drivers' behavior is not well represented. Contrary to the previous approach, speed data were collected with one and data analysis using a speed profile is made for data selection before building final models. A total of six speed prediction models were made according to the combination of horizontal and vertical alignments. The study predicts that the speed data analysis and selection for model building employed in this study can improve the prediction accuracy of models and be useful to analyze drivers' speed behavior in a more detailed way. Furthermore, it is expected that the operating speed prediction models can help complement the current design-speed-based guidelines, so more benefits to drivers as real road users, rather than engineers or decision makers, can be achieved.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.472-472
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• 2021

우리나라는 하천법 제10조, 소하천정비법 제3조에 하천기본계획 수립 또는 하천의 지정 및 변경고시 시 하천구역을 결정하도록 정의되어 있다. 하천구역 설정 시 일반적으로 하천의 제방이 위치하는 부지 및 제방하심측 토지경계를 하천구역으로 지정하고 있으나, 제방계획이 없거나 무제부 구간으로 활용되고 있는 구간의 경우 하천법 제10조 3항에서 5항까지 3가지 항목을 기준으로 계획하폭에 해당하는 토지, 댐·하구둑·홍수조절지·저류지의 계획홍수위 아래에 해당하는 토지경계, 철도·도로 등 제방의 역할을 하는 선형공작물 하심측 토지경계로 구분하고 있다. 하천구역의 경계설정의 경우 불연속적인 특징을 갖는 하천의 횡단측점 자료의 특성상 정확한 평면상의 경계를 파악하기 어렵고, 철도·도로 등 선형공작물 경계를 하천구역으로 설정 시 편입용지의 보상이 상이하고 모호한 기준으로 인해 다량의 민원이 발생하는 실정이다. 본 연구에서는 부산시에 위치한 지방하천 대천천을 대상지로 설정하였으며, 계획홍수위를 기반으로 홍수범람예상도를 작성하여 정밀계획홍수위선을 산출하고 이를 지형자료와 중첩하여 계획홍수위 경계를 추출하였다. 또한 무제부 구간 내 드론촬영을 실시하여 대상지 드론영상 기반 3차원 정밀 지형자료를 구축하고 이를 앞서 산정한 계획홍수위 경계자료와 중첩하여 정밀 하천구역을 설정하였다. 대상지 정밀 하천구역 산정 결과를 기반으로 도심지내 하천과 도시외곽 하천으로 구분하고 다시 도심지내하천은 암거(복개)구간과 개거구간, 도시외곽하천은 유제부와 무제부 구간으로 구분하여 정밀 하천구역 결정기준을 수립하였다. 본 연구를 통해 대천천유역을 대상으로 실시한 무제부 구간 하천구역 결정과정을 기반으로 하천유형별 3차원 하천구역 산정기법을 정립하였다. 향후 해당기법을 실무에 적용하여 하천구역 산정 시 모호한 하천경계부분 또는 토지소유주와 담당부처 간 하천구역 논의 시 기반자료로 활용될 수 있을 것으로 사료되며, 기본계획 수립 시 해당 기법 적용을 통해 보다 정확한 하천구역 경계 수립이 될 수 있을 것으로 기대된다.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.43-54
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• 2010

In recent years there have been studies on tour based approaches for freight travel demand modelling. The purpose of this paper is to analyze tour type choice behavior of commercial vehicles which are divided into round trips and chained tours. The methods of the study are based on the decision tree and the logit model. The results indicates that the explanation variables for classifying tour types of commercial vehicles are loading factor, average goods quantity, and total goods quantity. The results of the decision tree method are similar to those of logit model. In addition, the explanation variables for tour type classification of small trucks are not different from those for medium trucks', implying that the most important factor on the vehicle tour planning is how to load goods such as shipment size and total quantity.

• Korean Journal of Plant Resources
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• v.12 no.1
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• pp.50-61
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• 1999

The leaf morphological and anatomical characters about 17 taxa of Aster and its allied taxa were investigated to estimate taxonomic values. Leaf shapes of the treated taxa were divided into five types; elliptic, spathulate, lanceolate, linear, ovatodeltoid. These types were fixed in same taxa, but variable among different taxa, therefore useful as taxonomic character. Leaf margins were divided into four types; entire, serrate, dentate, incised, these types were invariable in most taxa, but variable among individual in same taxa such as Kalimeris incise, Aster spathulifolius. The size and shape of leaf epidermal cell, the size and distributional numbers per 10$\textrm{mm}^2$ of stomata, deposit feature of cuticle were not distinguished clearly from treated taxa, but presence of stomata on adaxial surface, size and distributional numbers per 10$\textrm{mm}^2$ of stomata were useful taxonomic characters in some taxa such as Gymnaster koraiensis, Aster altaicus var. uchiyamae, Aster tripolium, Heteropappus arenarius. The leaf trichomes were divided into five types by basic form, sculpturing on their outer surface and cell arrangement; uniseriate granulate conical type, uniseriate psilate conical type, uniseriate psilate filiform type, globular type, biseriate vesicular capitate type. In spite of various habitat, basic morphology of trichomes were not changed, therefore, it was thought to be good taxonomic character.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.2
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• pp.50-61
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• 2019

The aspects of typhoon-induced surges were classified into three types at the Western coast, and their characteristics were examined. The typhoons OLGA (9907) and KOMPASU (1007) were the representative steep types. As they pass close to the coasts with fast translation velocity, the time of maximum surge is unrelated to tidal phase. However, typhoons PRAPIROON (0012) and BOLAVEN (1215) were the representative mild types, which pass at a long distance to the coasts with slow translation velocity, and were characterized by having maximum surge time is near low tide. Meanwhile, typhoons MUIFA (1109) and WINNIE (9713) can be classified into mild types, but they do not show the characteristics of the mild type. Thus they are classified into propagative type, which are propagated from the outside. Analyzing the annual highest high water level data, the highest water level ever had been recorded when the WINNIE (9713) had attacked. At that time, severe astronomical tide condition overlapped modest surge. Therefore, if severe astronomical tide encounter severe surge in the future, tremendous water level may be formed with very small probability. However, considering that most of the huge typhoons are mild type, time of maximum surge tends to occur at low tide. In case of estimating the extreme water level by a numerical simulation, it is necessary not only to apply various tide conditions and accompanying tide-modulated surge, but also to scrutinize typhoon parameters such as translation velocity and so on.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2023-2027
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• 2009

본 연구는 현재와 과거의 하도 지형자료 분석을 통하여 만경강에서 나타나는 폐천(Abandoned channel)을 파악하고, 유형을 폐쇄형, 개방형, 육화형 폐천으로 구분하여 각각의 본류구간과 함께 식물상 및 식생분포 특성을 비교하였다. 만경강의 경우 1918년 하도 형태가 경지정리 및 치수사업에 따른 제방축조 등 인위적인 절단(Engineered cutoff)으로 8개소 이상의 구간에서 하도 선형이 크게 변경됨으로써 폐천이 형성되는 것으로 나타났다. 현재 폐천부지는 육화형태의 농지 이용 및 개방형 또는 폐쇄형의 습지로 유지되는 것으로 조사되었다. 폐천 유형에 따라 나타난 식물상은 폐쇄형 56종류, 개방형 31종류로 조사되었다. 육화형의 본류의 경우 보에 의한 영향으로 달뿌리풀 (Phragmites japonica)과 저수로 검정말(Hydrilla verticillata) 등의 수생식물이 우점하는 정체수역이 나타났다. 개방형 폐천은 갈수기에도 수심이 깊은 수역이 확보되어 본류에 비하여 출현종수가 높았다. 폐쇄형 폐천은 연꽃(Nelumbo nucifera), 애기부들(Typha angustifolia) 등의 다양한 수생식물이 출현하여 본류에 비해 안정된 습지 생태계를 유지하였다. 만경강의 개방형과 폐쇄형 폐천은 수생식물의 증가와 전형적인 습지생태계를 유지하고 있었으며 본류의 정체수역이 관찰되었다. 본래 하천의 연속성을 향상하기 위한 유수생태계의 복원은 하천의 건강성을 향상하기 위한 방안이 될 것이다.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.626-631
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• 2006

본 연구는 2006년 7월 집중호우에 의해 많은 인적.물적 피해가 발생한 강원도 지역의 피해 현장을 조사하였으며, 그 중 성토사면붕괴를 붕괴유형별로 구분하고 발생원인과 특성을 분석하여 그에 따른 적절한 대책방안을 제시하였다. 집중호우에 의한 성토사면의 붕괴유형 중 토석류에 의한 도로횡단 배수구조물의 기능상실로 유수가 노면으로 침출되고 수압이 발생하여 도로가 유실된 유형과 하천선형 불량으로 만곡수충부(물이 직접 부딪히는 부분)에서 유속이 빨라져 세굴에 의한 붕괴가 전체성토붕괴사면의 83%를 차지하였다. 이에 대한 대책방안으로는 토석류를 계곡상부에서 부터 예방할 수 있는 방법으로 사방댐 및 그물망 공법 등이 좋은 대책방안이 될 수 있으며, 토석류에 의한 유송잡물을 모두 통과할 수 있도록 충분히 큰 배수시설을 설치하는 방법도 좋은 대책방안이 될 수 있다. 무엇보다 열대성 국지 폭우를 이제 일상의 한반도 기후현상으로 받아들여 주먹구구식의 일회성 대책방안을 지양하고 바뀐 강우특성과 빈도를 고려하여 계획 홍수위를 재산정하고 그에 따라 하천정비계획을 재검토해야 할 것이다.

• Korean Journal of Social Welfare
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• v.62 no.4
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• pp.171-192
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• 2010

The purpose of this study is to examine factors on wage of the Disabled. This study attempts to identify organizational effects on wage of the disabled. Then, this study adopts hierarchical linear model for the study purpose. Data used for this article is the survey on the vocational rehabilitation facilities in Seoul. The results are as follows. First, wage of the disabled is different from organizations as well as individuals. So, there are necessities in the consideration of organizational effects and the application of hierarchical linear model. Second, effects on wage of the disabilities controlling individual factors such as age, educational level, period using the facilities, sex, whether or not beneficiary, type of disability are different from organization. Finally, there are interaction effects of type of disability and organizational character variables. The implications of these findings are as follows. First, more political concerns should be given on the management of vocational rehabilitation facilities. Second, it is needed to concern about vocational rehabilitation of the mentally disabled.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.39-53
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• 2015

The paper analyzes factors to affect pedestrian volumes by land-use type using 2012 Seoul Pedestrian Survey. First of all, five groups were classified based on land-use types around survey points such as residential, commercial, industrial and green uses, using k-average cluster analysis. Then, differences in average pedestrian volumes by group were compared for a day and time of day. In addition, multiple regression analysis was employed to identify factors to affect pedestrian volumes, considering physical features, land use types, public transportation accessibility, and socio-economic indices as independent variables by spatial hierarchy. Model results show that the walkway width positively influenced on pedestrian volumes for all groups, whereas other variables differently affected by group. Our results can be used as basic data for establishing polices with respect to pedestrian road design and improvement as well as estimating pedestrian demand by land-use type.