• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.139-146
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• 2003

The objective of the presented study is to develop an efficient procedure of proof load testing for existing bridges. By analytical methods, some of these bridges are not adequate to carry normal highway traffic. However, the actual load carrying capacity is often much higher than what can be determined by conventional analysis. Proof load testing can reveal the hidden strength reserve and thus verify the adequacy of the tested bridge. Proof load level required for meaningful tests should be sufficiently higher than legal load. In the state of Michigan, the legal 11-axle truck can weigh up to 685 kN. In this study, a combination of two military tanks and two Michigan 11-axle trucks was used. The proof loads were gradually increased to ensure the safety of the test. After each move, measurements were taken. For the considered bridge, stress levels were rather low compared to pre-test analysis results. This is due to incorrect material strength, structural contribution of nonstructural components such as parapets and railings, and partially fixed supports.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.405-405
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• 2019

최근 기후변화 및 지구온난화의 영향으로 집중호우, 돌발홍수, 가뭄 등 기상 이변이 빈번하게 발생하고 있어 물관리의 불확실성과 복잡성이 매우 높아지고 있다. 대규모 하천의 경우 다목적댐과 다기능보를 이용하여 홍수 및 가뭄에 대응이 비교적 용이하나, 중소하천의 경우 하천길이가 짧고 하천경사가 급해서 홍수파의 이동시간이 짧기 때문에 홍수대비를 위한 시간이 매우 짧다. 또한 중소하천 관리를 담당하는 지자체는 열악한 재정 여건과 전문인력 및 기술력 부족으로 인해 예방보다 사후복구에 집중하는 상황이며, 최근 하천 고수부지를 수변공원, 천변주차장 등으로의 공간적 활용이 증가됨에 따라 홍수발생시 위험성도 증가하고 있어 예방 및 대응 중심의 홍수 모니터링 기준 수립이 시급하다. 이에 K-water는 공익사업의 일환으로 K-water의 홍수 및 하천관리 노하우를 지자체와 공유하고 있다. 해당지자체의 과거 기상 및 수문자료들을 활용하여 홍수분석을 수행하고 지자체 중소하천에 최적화된 우량 및 수위 홍수 모니터링 기준을 수립하여 선제적 홍수대응을 할 수 있는 여건을 조성하였다. 또한 해당지자체의 우량 수위관측소의 분포와 용수전용댐 및 농업용저수지를 반영하여 유역특성을 고려한 홍수분석모형을 구축하였으며, 예상강우에 따른 주요 지점별 예상수위 및 도달시간 분석으로 지자체 담당자의 홍수대응을 지원하고자 한다. 하천 수위국 기준의 우량 알람은 하천 수위 상승 전 예비 알람의 성격으로 수위국의 수위가 상승하기 전 대비할 수 있는 선제적 대응 예방시간 확보에 도움이 될 수 있다. 또한 단계별 수위모니터링 기준에 의거하여 보행자 및 차량 통행제한 등의 조치를 취할 수 있으며, 제방월류 전 사전대응시간을 확보할 수 있어 자자체에서 능동적으며 선제적인 홍수 대응이 가능할 것으로 판단된다. 하지만 하천 수위국의 상황이 홍수에 따라 변화될 수 있으며, 홍수량 재산정 또는 하천기본 계획의 재수립 등 정책적, 현실적인 상황의 변화로 인해 모니터링 기준이 변화되어야 하는 경우에는 지속적인 보완이 필요할 것으로 사료된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.267-273
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• 2009

To predict the urban growth trend and to prevent the metropolitan problems, it is important to track the spatio-temporal changes in the urban spatial structure. Commuting is inevitable and regular activities emerging in the metropolitan region. Therefore, it can be a useful to examine the interregional interaction and the urban spatial change. The purpose of this study is to investigate the urban interaction between Seoul and cities around Seoul Metropolitan Region, and GIS functions helped analysis and visualized results. An analysis of current commuting data using the Gravity Model suggests that the interaction between Seoul and its peripheral cities has been intensified from 1990 to 2000 and that the urban interaction was closely related to the distance. And the southward distribution of the cities having a strong interaction with Seoul accounts for the imbalance in growing of Seoul Metropolitan Region.

• Journal of Korean Society of Transportation
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• v.22 no.1 s.72
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• pp.43-62
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• 2004

Conventionally the estimation method of the origin-destination Matrix has been developed by implementing the expansion of sampled data obtained from roadside interview and household travel survey. In the survey process, the bigger the sample size is, the higher the level of limitation, due to taking time for an error test for a cost and a time. Estimating the O-D matrix from observed traffic count data has been applied as methods of over-coming this limitation, and a gradient model is known as one of the most popular techniques. However, in case of the gradient model, although it may be capable of minimizing the error between the observed and estimated traffic volumes, a prior O-D matrix structure cannot maintained exactly. That is to say, unwanted changes may be occurred. For this reason, this study adopts a conjugate gradient algorithm to take into account two factors: estimation of the O-D matrix from the conjugate gradient algorithm while reflecting the prior O-D matrix structure maintained. This development of the O-D matrix estimation model is to minimize the error between observed and estimated traffic volumes. This study validates the model using the simple network, and then applies it to a large scale network. There are several findings through the tests. First, as the consequence of consistency, it is apparent that the upper level of this model plays a key role by the internal relationship with lower level. Secondly, as the respect of estimation precision, the estimation error is lied within the tolerance interval. Furthermore, the structure of the estimated O-D matrix has not changed too much, and even still has conserved some attributes.

• Spatial Information Research
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• v.4 no.2
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• pp.131-146
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• 1996

The purpose of this study is to extract the main locational factors to affect the location of fastfood stores in Kangnam -Gu, Seoul by using Geographic Information Systems. The Franchise system, which came to be employed in full scale since 1990, now enjoying the booming period, especially fast food industry. The procedure of this research has four steps. First, the spatial distribution of fastfood chain stores in Seoul is analyzed by the land use and road map. Second, the spatial variations of fastfood stores in dong districts of Seoul is explained by multiple regression analysis. Third, the main locational factors to affect the location of fast food stores in Kangnam -Gu are extracted by demand and supply sides using GIS technologies. Finally, the potentiallocational zones where are selected by extracted locational factors are compared with the actual distribution of f astf ood stores in Kangnam - Gu. In terms of demand side, the main locational factors include commercial and service facilities, sub¬ways and bus stops which have a lot of pedestrians, and large apartment districts that have high popu¬lation densities. In terms of supply sides, the main locational factors include land use types and land value, accessibility. After fast food chain stores of Kangnam -Gu are overlaid final potentiallocational zones extracted by demand and supply sides of locational factors, it can be identified that over 80 % of fastfood stores are located in the potentiallocational zone. In conclusion, this study shows that spatial analysis functions may potentially be improved using GIS technologies. However there are still difficulties for the locational analysis for service industries to col¬lect appropriate data in terms of computerized base maps as well as consumer behavior and store characteristics itself.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.3
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• pp.459-475
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• 2008

This study analyzes the network structure of the Metropolitan Seoul subway system by applying complex network analysis methods. For the purpose, we construct the Metropolitan Seoul subway system as a network graph, and then calculate various indices introduced in complex network analysis. Structural characteristics of Metropolitan Seoul subway network are discussed by these indices. In particular, this study determines the shortest paths between nodes based on the weighted distance (physical and time distance) as well as topological network distance, since urban travel movements are more sensitive for them. We introduce an accessibility measurement based on the shortest distance both in terms of physical distance and network distance, and then compare the spatial structure between two. Accessibility levels of the system have been getting up overall, and thus the accessibility gaps have been getting lessen between center located subway stops and remote ones during the last 10 years. Passenger traffic volumes are explored from real passenger transaction databases by utilizing data mining techniques, and mapped by GIS. Clear differences reveal between the spatial patterns of real passenger flows and accessibility. That is, passenger flows of the Metropolitan Seoul subway system are related with population distribution and land use around subway stops as well as the accessibility supported by the subway network.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.41-49
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• 2009

This research conducted a survey on the feeding crane's size, formation and distribution distance subsequent to road pattern and feeding flock's size during the wintering season eight times at the Cheolwon basin in Korea from December 2005 until February 2006. The survey results are as follows: First, the feeding flocks of the Red-crowned and White-naped Crane were found to mainly consist of two to four individuals. Mono-specific feeding flocks were more identified than hetero-specific feeding flocks in both Red-crowned and White-naped Cranes. There existed a significant difference in the ratio by size between the feeding Red-crowned and White-naped Cranes. The crane's average distribution distance from the paved road was much farther than from the unpaved road, paved farm road and unpaved farm road. In case of the white-naped crane, there was a difference in its distance length from between the road and farm road and there existed a significant difference only in the paved road in the distance length by road pattern between these two bird species[Red-crowned and White-naped Crane]. Such a result indicates that crane species don't prefer the road with frequent vehicular traffic to the road with low vehicular traffic. 5 or more individuals of feeding flocks of the Red-crowned Crane were located at a farther distance length from the paved road comparing to less than 5 individuals of the whole feeding flocks and less than 5 individual feeding flocks. 5 or more individuals of feeding flocks of the White-naped Crane were located at a farther distance length from the paved road, paved farm road and unpaved farm road than less than 5 individuals of feeding flocks of the White-naped Crane; however, there existed no difference in distance length subsequent to their group size. Conclusively, it was found out that the flocks with a larger size were more greatly affected by interrupting factors. Considering such results, there seems to be a more relation to the fact that larger size feeding flocks of crane species have a higher efficiency in the lookout for their surroundings.

• Journal of Environmental Impact Assessment
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• v.29 no.1
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• pp.1-7
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• 2020

This study aims to evaluate the effect of artificial facilities constructed afterthe release of the civilian controlled zone (CCZ) in Cheorwon on the inhabitation of cranes. The study site was released from the CCZ in 2012, and several barns have been built since 2017. The average number of Red-crowned Cranes was 9.3±4.3 individuals (±Standard Deviation) in the period before the release of the CCZ from 2009 to 2012, and it decreased by ca. one third of Red-crowned Crane's average individuals were showing 3.5±0.5 individuals after release. The average number of White-naped Cranes also appeared to be decreased by ca. 90% from 63.3±24.6 to 6.0±6.0 individuals. This results suggest that the construction of greenhouses and barns after the releasing of the CCZ affected the decrease of the population of these two crane species. In the case of Red-crowned Crane, the core area tended to move away from the area where barns were built. However, the distribution range of Red-crowned Cranes did not change significantly we expected because the study area was not their favorite place since 2012 when the area was released from the CCZ. The density of the White-naped Crane was relatively high even in the area where greenhouses were built, but after 2017 when the barn was built intensively, core habitat of crane became shrink and fragmented. These results suggest that both Red-crowned Cranes and White-naped Cranes response sensitively against habitat change due to the construction of barns. Since the release of the CCZ, the construction of the greenhouse has been influenced on the distribution of cranes, but subsequently, the construction of the barn seems to have caused a bigger change in their core habitat because the passage of people to barns is more frequent than the greenhouses.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.1-12
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• 2006

In order to estimate a dynamic origin and destination demand between on and off-ramps in the freeways, a traffic flow theory can be used to calculate a link distribution proportion of traffics moving between them. We have developed a dynamic traffic estimation model based on the three-phase traffic theory (Kerner, 2004), which explains the complexity of traffic phenomena based on phase transitions among free-flow, synchronized flow and moving jam phases, and on their complex nonlinear spatiotemporal features. The developed model explains and estimates traffic congestion in terms of speed breakdown, phase transition and queue propagation. We have estimated the link, on and off-ramp volumes at every time interval by using traffic data collected from vehicle detection systems in Korea freeway sections. The analyzed results show that the developed model describes traffic flows adequately.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.421-428
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• 2014

Total 20 surface sediments were collected in Anjung bay to investigate the physicochemical environment and heavy metal contents. The physicochemical investigation ranged from 6.41% to 11.68% (average $9.52{\pm}1.28%$) for ignition loss (IL), from 17.99 mg/g to 43.84 mg/g (average $27.53{\pm}6.39mg/g$) for chemical oxygen demand (COD), and from 0.05 mg/g to 0.61 mg/g (average $0.17{\pm}0.14mg/g$) for acid volatile sulfide (AVS) with significant correlation between water content (W/C) and COD. A contour of spatial distribution indicated higher organic pollution at the bottom of ascidian, Stylea clava, cultural waters. Most of metals contents was not exceeded the NOAA's effect range-low (ERL). Estimated enrichment factor (EF) ranging 0.96-1.12 indicated that the sediment environment of the studied waters was relatively pristine from heavy metal pollution in spite of increased vessel traffics, so far.