• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.75-82
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• 2013

This paper proposes a $O(n^2)$ polynomial time algorithm to obtain optimal solution for Traveling Salesman problem that is a NP-complete because polynomial time algorithm has been not known yet. The biggest problem in a large-scale Traveling Salesman problem is the fact that the amount of data to be processed is $n{\times}n$, and thus as n increases, the data increases by multifold. Therefore, this paper proposes a methodology by which the data amount is first reduced to approximately n/2. Then, it seeks a bi-directional route at a random point. The proposed algorithm has proved to be successful in obtaining the optimal solutions with $O(n^2)$ time complexity when applied to TSP-1 with 26 European cities and TSP-2 with 46 cities of the USA. It could therefore be applied as a generalized algorithm for TSP.

• Journal of the Korean association of regional geographers
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• v.15 no.2
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• pp.273-281
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• 2009

Kimpo international airport logistics complex had been the most busiest airfreight gateway in Korea during last century but, after the grand open of Incheon international airport in 2001, it had lost its major role as a national airfreight hub facilities. However, owing to its locational advantages in Seoul metropolitan area. Kimpo airport logistics park still acts like an urban logistics distribution center in these days. Caused by the KAC's profit oriented policies, the Kimpo airport logistics park's public function as an urban distribution center might be curtailed in the future. Therefore, several laws and ordinances related to national and regional logistics strategies should be modified to prevent it.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.400-403
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• 2012

Laboratory experiments were conducted for tsunami inundation to an urban area with large building roughness. The waterfront portion of the city of Seaside which is located on the US Pacific Northwest coast, was replicated in 1/50 scale in the wave basin. Tsunami heights and velocities on the inundated land were measured at approximately 31 locations for one incident tsunami heights with an inundation height of approximately 10 m (prototype) near the shoreline. The inundation pattern and speed were more severe and faster in some areas due to the arrangement of the large buildings. Momentum fluxes along the roads were estimated using measure tsunami inundation heights and horizontal fluid velocities. As expected, the maximum momentum flux was near the shoreline and decreased landward. Inundation heights and momentum flux were slowly decreased through the road with buildings on each side. The results from this study showed that the horizontal inundation velocity is an important factor for the external force of coastal structures.

• Journal of the Korean association of regional geographers
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• v.10 no.2
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• pp.252-266
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• 2004

This study analyzes the influence of the construction of a high-speed railroad on territorial organization in France. After development of a new transportation network, the French territorial organization has been largely modified. Many economic urban areas are modified by their position in the territorial hierarchy according to their condition of connection with the TGV network. At first, spatial convergence is the most important effect of the TGV network construction. Second, the development of a transportation network concentrated in the Paris area has influence as an intensified factor on metropolitan areas and as a weakening factor on middle- and small-sized cities. Thus, this system has risk in increasing territorial imbalance in France. Third, to implant an economic activity zone around new TGV stations, a new town or a new economic center starts to develop. This is going to grow into a second core outside of the old city center so that regional spatial organization is transformed from a mono-polarized(mono-centric) organization to a multi-polarized(polycentric) one. Lastly, the integration of the EU railroad system enhances the concentration of economic activity in European metropolitan areas as each metropolitan area tries to develop more competitive space for its rising position in the global urban hierarchical system.

• Water for future
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• v.29 no.3
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• pp.143-152
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• 1996

The hydraulics of flow within the covered reach of urban streams is very complicated due to the accumulation and interference effect of eddies around the multiple piers supporting the covering slab. An extensive experimental study is done to quantitatively estimate the backwater rise effect caused by various arrays of multiple piers. The factors governing the backwater rise are found out to be the contraction ratio due to the piers, Froude number of the flow, longitudinal pier spacing, and the length of the covered reach. For a single section of lateral pier arrays the effect of contraction ratio and Froude number on the backwater rise is analyzed and a multiple regression equation is derived. The effect of multiple piers, arrayed in both lateral and longitudinal directions, on the backwater rise is analyzed in terms of the contraction ratio, Froude number,longitudinal pier spacing and the total length of the covered reach. A multiple regression equation for the backwater rise estimation is proposed based on the experimental data collected in the present study.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.933-941
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• 2010

KORAIL has improved profitability through abolition of nonprofitable route and withdraw rolling stocks, operated at that route. as a part of that process, most sections of commuters' train are gone. presently, gyeongui-line and gyeongwon-line's commuter's trains are operated. Despite the abolition, there are demands for commuters' train. so, nonprofitable route operation policies are needed to meet the demands and connect seamlessly to KTX. In this study, we consider the overall operation policies and problems of commuters' train in the past. and then, we analyze foreign nonprofitable route, connected with high speed train, operation policies and search for the development suggestions for applying to the nonprofitable route between Iksan - jeonju section at Honam and joenra line.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.346-350
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• 2010

도시화재의 연소 확대성상을 모델화하기 위해 화재실의 개구를 통하여 분출하는 열기류의 온도 평가 실험을 실시하였다. 실험은 축소모형 형태로 개구 조건과 화원조건에 의해 진행이 되었다. 실험 결과 온도분포 Trajectory는 개구종횡비 n에 의해 횡정(橫井)의 연구결과와 비교하여 n=2일때를 제외하고는 다른 경향을 나타냈다. 동일 조건에서 분출화재보유열량 $Q_{ef}$은 개구 조건이 횡장창($B0.2m{\times}H0.1m$)이고, 단일개구일 때 가장 높은 값을 나타냈다. 또한, 분출화재의 발생 한계 발열속도 $Q_{verit}$에서도 굴웅아(堀雄児)의 연구와 유사한 결과를 보이며, 다른 개구조건보다 횡장창($B0.2m{\times}H0.1m$)일 때 높은 값을 나타냈다.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.623-631
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• 2011

In recent decade, the occurrences of typhoon and severe storm events are increasing trend due to the climate change. And the intensity of natural disaster is more and more stronger and the loss of life and damage of property are also increasing. Therefore, this study tried to understand the impact of climate change on urban drainage system for prevention and control of natural disaster and for this, we selected Gyeyang-gu, Incheon city as a study area. We investigated the climate models and scenarios for the selection of proper model and scenario, then we estimated frequency based rainfall in hourly unit considering climate change. The XP-SWMM model was used to estimate the future flood discharge on urban drainage system using the estimated frequency based rainfall. As a result, we have known that the study area will be overflown in the future and so we may need prepare proper measures for the flood prevention and control.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.897-901
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• 2008

The objective of this study is to conduct land cover classification respectively using Landsat TM data collected on Oct., 1985 and KOMPSAT-1 EOC data collected on Jan., 2000 covering Gumi city, Gyeongbuk Province and to detect urban change by comparing between both land cover maps. Multispectral images of Landsat TM have spatial resolution of 30m are well known as useful data for extracting information related to landcover, vegetation classification, urban growth analysis and so forth. In contrast, as KOMPSAT-1 EOC collects panchromatic images with relatively high spatial resolution of 6.6m. We try to analyze how accurate landcover classification result is able to be derived from the panchromatic images. As the results of the study, the KOMPSAT EOC data with high resolution greater than 4 times showed higher classification degree than Landsat TM data. It was ascertained that the built-up region was extended by three to four times in the last 15 years between 1985 and 2000. In the contrast, it was shown that the forest region was decreased by 15% to 27% and the grass region including agricultural region was decreased by 28% to 45%.

• Journal of the Korean Geographical Society
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• v.49 no.5
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• pp.728-746
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• 2014

The purpose of this study is to analyze the influence of the selective migration of young age group and the stage migration which has proceeded through generations, on the transition of fertility and the population growth in the rural and urban in the case of Jeollabuk-do. For this, we use O-D matrix of 20-34 age group, the distribution of that group and women of child bearing age, and vital statistics in 1970-2010. The major findings of this study are as follows. First, the outflows from their birth place are common and dominant features of 20-34 age group in each time. Second, there is the stage migration which preceding generation moved from the rural areas to the cities in Jeollabuk-do and following generation has moved from the cities to Seoul metropolitan area. Third the selective outflow migration of young age group has leaded to reduction of the childbearing population, declining birthrate, aging and natural population decline. Due to the stage migration, these depopulation processes occurred in rural area in the past, and currently it expands to the cities with about 15 years time gap. In fact, there have been the natural population decrease which annual number of deaths exceed that of births from the late 1980s in the most rural areas and in the early 2000s, such a phenomenon has been confirmed also in urban areas. Therefore, this study concludes that the stage migration through generations is one of the crucial factor to the population growth in local cities and also brings out the step-wise population decrease in settlement hierarchies.