• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1551-1558
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• 2013

The purpose of this study is deriving proper plan which is improving functionality of three-way intersection in two-way road by using shoulder. Alternatives of this study were considered as installation of yield lane and application of TWLTLs (Two-Way Left-Turn Lanes). Case studies to utilize alternatives were limited to national and local roadways which is wider than 11 meters due to be required 3 lanes. Under various traffic conditions such as traffic volume of each direction and left-turn, alternatives were analyzed by simulation. As a results, application of TWLTLs was better than installation of yield lane in terms of improving rate (8.0% vs. 3.7%). Application of TWLTLs is supposed to better alternative, however enough driver education is required to improving safety because it is different with existing driving pattern and/or behaviors. Some limitations and future research agenda have also been discussed by on-site inspections.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.1-12
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• 2012

Even though the semi-actuated signal control system based on image detectors has been spreading in Korea, any appropriate methods to evaluate the effectiveness and performance has not been established yet. Therefore, this research effort is aiming at developing a systematic method for evaluating the effectiveness and performance of the semi-actuated signal control system based on image detectors. To this end, this research firstly established measures of effectiveness(MOEs) and associated information to be surveyed from fields. Secondly, this research provided a procedure and methodology to evaluate any improvements due to the introduction of a semi-actuated signal control system based on image detectors. The developed methodology was examined at a case study site located in the city of Paju. As a result of the evaluation, the MOEs including traffic throughput, travel speeds, split usage rate, progression rate, etc. showed positive improvements though individual signalized intersections as well as coordinated corridors.

• Journal of Korean Society of Transportation
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• v.33 no.5
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• pp.470-477
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• 2015

VMS informs the public of traffic and weather information in real time and functions to facilitate traffic flow. However, as smart phone navigation becomes more popular with the rapid propagation of the smart phone, the efficiency and applicability of VMS are challenged. Accordingly, this study aims to investigate the drivers' preference for the traffic information service between VMS and smart phone navigation by conducting a survey using a stated preference in Busan Metropolitan City in August 2013. This study found that 60% of survey respondents prefer VMS to the smart phone navigation. Further analysis to investigate the preference focused on the smart phone users revealed that female, younger, more educated, and less experienced drivers more rely on the smart phone navigation. Consequently, this study implicates that private and governmental institutes have to take a measure to develop the integrated traffic information system.

• Journal of Korean Society on Water Environment
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• v.32 no.4
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• pp.367-374
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• 2016

In this study, the RDII impact on sewer designing in the upstream monitoring area (A site) was considered. Based on the long-term (1/1/2011~12/31/2011) rainfall and flow data consisting of 10-min interval sampling in the nearby design area (B site), the maximum RDII/DWF ratio was selected. The sewer network system at B site was evaluated by the Manning equation. Scenario 1 considering the hourly maximum flow with respect to the flow velocity showed that none of the sewer pipes satisfied the minimum flow velocity condition (0.6 m/s), and 40 pipes did not achieve half of the velocity condition. In scenario 2 considering I/I, 1 the pipes satisfied 0.6 m/s, and 35 pipes showed 0.3 m/s. Scenario 3 reflected the effect of RDII. Velocities in 26 pipes were less than 0.3 m/s, and 4 pipes satisfied the velocity condition. With respect to the allowance rate, 17 pipes were shown to have more than 99%, and none of the pipes satisfied less than 95% of the allowance rate in scenario 1. In scenario 2, 17 Ed: Per the Table pipes showed more than 99% and one pipe showed less than 95%. In scenario 3, 16 pipes showed more than 99% of the allowance rate, and 19 pipes showed less than 95%. Based on these results, it is predicted that deposition would occur due to the slow flow velocity; however, capacity would not be a problem.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.3
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• pp.92-101
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• 2012

Trip demands and patterns on weekends have been changed significantly over the past decade due to the income growth and the spread of the 5-day workweek in Korea. The increased weekend trips for shopping, leisure activities, entertainment and friendship have exacerbated traffic congestion in major highways or principal arterial roads from Friday afternoon through Sunday. Therefore, it is necessary to focus on travel demand forecasts and transport policies for weekend trips by investigating specific characteristics of the trips. Previous research efforts focus on simple analysis of characteristics of weekend trips and comparison of travel characteristics between weekdays and weekends. The paper analyzes the differences between weekday and weekend trips via statistical analyses to derive multiple types of characteristics of weekend trips, and develops Tobit models to identify key factors that may affect the number of trips, using Seoul city's weekend trip survey data in 2006. The model results show that weekend trips appear differently from weekdays by household or individual characteristics. Age, residence area and type of residence affected the number of trips, regardless of the type of the day, whereas gender, occupation, income, presence of household vehicle showed different impacts on trips between weekdays and weekends.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.34-39
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• 2006

1. 철도, 도로, 항공, 해운 등 교통수단별 현황을 조사한 결과, 현재까지의 교통정책이 도로교통 우선 위주였기 때문에 철도는 뛰어난 환경성 및 경제성을 가지고 있음에도 불구하고 수송분담율이 비교적 저조한 편이었다. 그러나, 향후 정부의 사회기반시설 구축에 있어서 국가 기간 철도망 확대와 대도시 지하철 및 경량전철 건설을 통한 도심철도망과 간선철도망의 연결 등을 통하여 철도의 이용이 훨씬 용이해질 것으로 보이며 이에 따라 철도의 이용률도 크게 상승할 것으로 예상된다. 2. 교통수단별 일반현황은 다음과 같다. 1) 철도교통은 여객수송량이 다소 증가하고 있는 추세였는데, 2004년 KTX의 개통으로 인하여 여객수송량이 급증하였으나, 화물수송은 약간 감소하는 추세이다. 2) 도로교통은 공로의 경우 이용량이 크게 감소하고 있으나, 자가용의 경우에는 승용차의 급증에 의하여 도로의 분담률이 증가하고 있다. 그러나, 도로망의 확충이 자동차의 증가량을 따르지 못하는 것과 자동차가 도시에 밀집됨에 따른 교통체증에 따라 자가용 차량의 1일 평균 주행거리가 짧아지는 등 수송량이 크게 증가하지는 않고 있다. 3. 각 교통수단별 환경경제성을 조사한 결과는 다음과 같았다. 1) 단위수송량당 에너지 소비율은 여객의 경우 철도가 75.97kcal/인 km에 불과한 반면에 버스는 415.43, 택시는 1,192.24kcal/인 km에 달하여 각각 철도의 5.5배 및 15.7배나 많은 에너지를 소비하는 것으로 나타났다. 화물의 경우에도 철도는 105.98kcal/톤 km에 불과한 반면에 도로는 1,674.21kcal/톤 km에 달하여 철도의 무려 15.8배의 에너지를 사용하는 것으로 나타나, 철도가 에너지 효율성 면에서 도로 교통수단보다 월등히 앞서는 친환경적이면서 경제적인 교통수단임을 알 수 있다. 2) 도로와 철도의 단위수송량 당 CO의 배출량은 도로가 1,531.2kg/백만인 km로 철도의 167.4kg/백만인 km에 비하여 9배나 되었다. 그러나, 탄화수소의 경우는 도로가 216.5kg/백만인 km으로 철도의 68.0kg/백만인 km의 3배를 넘는다. 미세먼지의 경우는 도로가 철도보다 약간 더 많은 수준이었으나, NOx와 $SO_2$는 오히려 철도가 오히려 약간 더 높게 나타났다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1093-1099
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• 2016

Currently, there are 499 metropolitan subway stations in Korea, but there are not many studies on the influence zone of linkage between railway station and public transport. Existing studies have been studied almost in terms of accessibility.. In addition, the existing research on the influence zone of linkage using survey data and statistics, there is a limit to the theoretical basis and analysis techniques. In this paper, we propose a new method to select on the influence zone of linkage, It is a GIS analysis technique using the spatial data of the railway station user as the large data of the traffic card. We applied the GIS analysis technique for select the influence zone of linkage based on the travel time of the network for each public transportation system. As a result, it was confirmed that the influence of the link of 15 minutes on the local bus, 20 minutes on the city bus and 25 minutes on the intercity bus were clearly distinguished according to the difference in network access time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.147-150
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• 2008

The real road network is regarded as a grid, and the grid is divided by fixed-sized cells. The path-finding is composed of two step searching. First searching travels on the abstract graph which is composed of a set of psuedo vertexes and a set of psuedo edges that are created by real road network and fixed-sized cells. The result of the first searching is a psuedo path which is composed of a set of selected psuedo edges. The cells intersected with the psuedo path are called as valid cells. The second searching travels with $A^*$ algorithm on valid cells. As pruning search space by removing the invalid cells, it would be possible to reduce the cost of exploring on real road network. In this paper, we present the method of creating the abstract graph and propose a path-finding algorithm on the abstract graph for extracting search space before traveling on real road network.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.974-983
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• 2005

In genetic algorithms with lotus-based encoding, static gene reordering is to locate the highly related genes closely together. It helps the genetic algorithms to create and preserve the schema of high-quality effectively. In this paper, we propose a static reordering framework for linear locus-based encoding. It differs from existing reorderings in that it is independent of problem-specific knowledge. It makes a complete graph where weights represent the interelationship between each pair of genes. And, it transforms the graph into a unweighted sparse graph by choosing the edges having relatively high weight. It finds a gene reordering by graph search method. Through the wide experiments about several problems, the method proposed in this paper shows significant performance improvement as compared with the genetic algorithm that does not rearrange genes.

• Journal of KIISE
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• v.43 no.10
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• pp.1131-1143
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• 2016

How can we effectively compress big graphs composed of billions of edges? By concentrating non-zeros in the adjacency matrix through vertex rearrangement, we can compress big graphs more efficiently. Also, we can boost the performance of several graph mining algorithms such as PageRank. SlashBurn is a state-of-the-art vertex rearrangement method. It processes real-world graphs effectively by utilizing the power-law characteristic of the real-world networks. However, the original SlashBurn algorithm displays a noticeable slowdown for large-scale graphs, and cannot be used at all when graphs are too large to fit in a single machine since it is designed to run on a single machine. In this paper, we propose a distributed SlashBurn algorithm to overcome these limitations. Distributed SlashBurn processes big graphs much faster than the original SlashBurn algorithm does. In addition, it scales up well by performing the large-scale vertex rearrangement process in a distributed fashion. In our experiments using real-world big graphs, the proposed distributed SlashBurn algorithm was found to run more than 45 times faster than the single machine counterpart, and process graphs that are 16 times bigger compared to the original method.