• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.1-14
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• 2024

The most optimal route-search algorithm thus far has introduced a method of applying node labels and link labels. Node labels consider two nodes simultaneously in the optimal route-search process, while link labels consider two links simultaneously. This study proposes a turn-label-based optimal route-search technique that considers two turns simultaneously in the process. Turn-label-based optimal route search guarantees the optimal solution of dynamic programming based on Bellman's principle as it considers a two-turn search process. Turn-label-based optimal route search can accommodate the advantages of applying link labels because the concept of approaching the limit of link labels is applied equally. Therefore, it is possible to reflect rational cyclic traffic where nodes allow multiple visits without expanding the network, while links do not allow visits. In particular, it reflects the additional cost structure that appears in two consecutive turns, making it possible to express the structure of the travel-cost function more flexibly. A case study was conducted on the metropolitan urban railway network consisting of transportation card terminal readers, aiming to examine the scalability of the research by introducing parameters that reflect psychological resistance in travel with continuous pedestrian transfers into turn label optimal path search. Simulation results showed that it is possible to avoid conservative transfers even if the travel time and distance increase as the psychological resistance value for continuous turns increases, confirming the need to reflect the cost structure of turn labels. Nevertheless, further research is needed to secure diversity in the travel-cost functions of road and public-transportation networks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2447-2453
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• 2013

In this study, the effects of weather conditions such as rainfall, discomfort index, snowfall, and sensible temperature on public transport demand in Seoul were analyzed using statistical data. The reasons were also derived from the survey. The data for the analysis were collected over the weekdays and weekends, and seasonal data of summer and winter were also gathered separately. Rainfall amount, discomfort index, and sensible temperature except snowfall amount, whose samples were insufficient, decreased the public transport demand by 2-7%. Rainfall amount and sensible temperature were statistically significant. Correlation analysis also showed that rainfall amount and sensible temperature are highly correlated with the demand. To find the reasons, the survey was conducted on citizens living in the Seoul Metropolitan Area. About 30% of the respondents wished to give up using bus when rainfall was heavy or temperature was low. On the contrary, auto and subway users increased by 10%. The results of this study could be used as the basic data when the public transportation planning or operation related policies according to the weather condition are concerned.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.113-132
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• 2003

Using nonradial data envelopment analysis(DEA) under assumptions of strong disposability and variable returns scale, this paper annually estimates productive. technical and allocative efficiencies of three publicly-owned rail transit properties which are different in terms of organizational type: Seoul Subway Corporation(SSC, local public corporation), the Seoul Metropolitan Electrified Railways sector (SMESRS) of Korea National Railroad(the national railway operator controlled by the Ministry of Construction and Transportation(MOCT)), and Busan Urban Transit Authority (BUTA, the national authority controlled by MOCT). Using the estimation results of Tobit regression analysis. the paper next computes their true productive, true technical and true allocative efficiencies, which reflect only the impacts of internal factors such as production activity by removing the impacts of external factors such as an organizational type and a track utilization rate. And the paper also computes an organizational efficiency and annually gross efficiencies for each property. The paper then conceptualized that the property produces a single output(car-kilometers) using four inputs(labor, electricity, car & maintenance and track) and uses unbalanced panel data consisted of annual observations on SSC, SMESRS and BUTA. The results obtained from DEA show that, on an average, SSC is the most efficient property on the productive and allocative sides, while SMESRS is the most technically-efficient one. On the other hand. BUTA is the most efficient one on the truly-productive and allocative sides, while SMESRS on the truly-technical side. Another important result is that the differences in true efficiency estimates among the three properties are considerably smaller than those in efficiency estimates. Besides. the most cost-efficient organizational type appears to be a local public corporation represented by SSC, which is also the most grossly-efficient property. These results suggest that a measure to sort out the impacts of external factors on the efficiency of rail transit properties is required to assess fairly it, and that a measure to restructure (establish) an existing(a new) rail transit property into a local public corporation(or authority) is required to improve its cost efficiency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.75-83
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• 2004

July 1, 2004 Seoul Metropolitan city is operating the Median Bus Lane System on Gangnam Main Street, Seongsan-Susaek-ro (Road) and Dobong- Mia-ro (Road) as one of the systematic reorganizations in public transportation. It has been assumed that there was an improvement in the speed of bus considering that the Median Bus Lane System practiced on Cheonho-daero (Main Street) since 1996 have had 35km/h on the average. If the Median Bus Lane goes into effect, there is a problem with the left turn on the crossroad. The buses go on the existing first lane so that the left fuming cars cannot help but turn left on the second lane. In case that the Median Bus Lane is put into practice, the left turn on the crossroad should not be allowed. However, if the left turn is not permitted on the crossroads in the aforementioned main streets, neighboring residents will complain about it and there will be some difficulties in finding other detour. On the premise that the prevalent left turn on the crossroads is allowed while the Median Bus Lane is being put into practice, this study suggests the separation of a stop line between buses and other vehicles as a way of fuming left in a safe manner and a way to calculate the appropriate distance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.24-35
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• 2016

This paper developed social equity indicators for evaluation of bus networks. This paper divided the social equity is into 4 categories such as horizontal equity, horizontal accessibility, vertical equity, and vertical accessibility and social equity was defined as integrated concept of these individual indicators. A simulation was performed by using the newly developed indicators to the toy network. On the basis of the simulation result, the social equity indicators are significant to the relative comparison for each zone. And, it was proved that optimal bus network alternative could be different depending on inclusion of the social equity indicators. Thus, it enabled to evaluate the bus network, as a public resource, considering not only the economic efficiency but also social equity. This paper suggested evaluation method for bus network considering social equity using indicators newly developed.

• Journal of the Korean Institute of Gas
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• v.22 no.5
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• pp.114-123
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• 2018

As recognizing the necessity of eco-friendly vehicles in order to reduce air pollution from road sector, Korean government has established and implemented a promotion policy which is encouraging the public transportation companies to purchase CNG buses in replacing diesel buses since 2000s. With CNG bus promotion policy, the number of CNG buses had been increased on the road of metropolitan area and big cities. However, increasing rate of CNG buses had been fluctuated between the decrease and the increase since year 2014. In this study, the impact of fuel cost competitiveness between diesel and CNG on CNG bus increasing volume was testified by simple regression, which was only assumed by precedent research on the CNG promotion policy. And this study suggested the necessity of harmonization among the related policies conducted by related Ministries. Eventually this study should contribute to enhance the validity of CNG bus promotion policy. And it is expected that Korean government should apply the new policy suggestion of this study in the establishment of government's promotion policy on LNG cargo trucks and Zero Emission Vehicles in the future.

• KIEAE Journal
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• v.9 no.2
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• pp.17-26
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• 2009

High-rise and high-density apartment complexes have been built and supplied on a large scale in the 1st period New Town of metropolitan areas since the late 1980s. Recently it has become necessary to improve those apartment complexes which have blight problems for aging more than about 20 years accompanying simultaneity and a large scale. The purpose of this study is to analyze actual conditions of high-rise and high-density apartments in a view of sustainable regeneration. The contents and methods of this study are as follows. First, the concept of high-rise and high-density in domestic apartment developments were identified through review of literature and the law. Second, development conditions of Bundang new town and 1st period new town were studied. Third, the evelopment conditions of high-rise and high-density apartments in cases of 6 apartment complexes were analyzed from points of view of sustainable development by literature review and a field study. The results of this study are as follows. First, high-density range in domestic apartments can be conceptualized as 600 persons/ha. High-rise range in domestic apartments can be onceptualized as more than 11 stories under 30 stories. Second, characteristics and subjects based on actual conditions analysis could suggest on physio-environmental aspect and socio-economic aspect. Major characteristics and subjects of the physio-environmental aspect were 1.satisfaction of convenient facilities and public transportation service, 2.shortage of parking space, 3.uniform & blight of community facilities, 4.uniformed building layout, and 5.uniform pattern of unit plan and low flexibility by the bearing wall structure. And those of the socio-economical aspect were 1.satisfaction of current community, 2.increase and diversity of needs of the elderly by socio-demography change, 3.improvement of size and method of apartment complex development and 4.raising of economic-sufficiency.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.623-628
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• 2007

Metro Subway System is widely known as the leader of public transportation in a metropolitan area. The signal interlocking is one of the most important organs that plays a major role in the system. By improving the quality of signal interlocking on of the traffic system and keeping its maintenance on a high level will not only repair the current state, but it will also let the PLC(Programmable Logic Controller). The Non-Vital relay of No. 3, 4 Line are the most one of the unstable system, device, which underwent a process of fine manufacture establishment and a close examination, obtained as a new device. Utilizing the equipment with cautious preservation on the system will enhance the current state of the signal device. Especially, the test for improvement and development based upon the technique that decreases the frequency of defect produced will further precipitate its efficiency. With authorization of imposing the newly made equipment will bring improvement to the signal technology and to the industry at largest extent.

• Land and Housing Review
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• v.2 no.1
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• pp.1-8
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• 2011

During the 1990's, five new towns were constructed around Seoul such as Bun-Dang and Il-San. These new towns are very popular since they were created based on systemic urban planning and they provide various residential amenities. Many people consider them livable cities. Taking such advantages, other small-scale new public and private developments continued around those new towns and consequently created 'agglomerated region with new development'. The most representative area is Bun-Dang and north-western Yong-In area which are formed along the Seoul-Busan expressway. This area is a mega-community having more than one million residents in 2005.Judging from recent development trends in the Seoul metropolitan area, it is expected that the formation of other 'agglomerated region with new development' would be continued for the time being. This study is aimed to analyze the residential environment of Bun-Dang and north-western Yong-In and find implications to the management of 'agglomerated region with new development'. The relevant existing studies have their limits, only focusing on analyzing current conditions and pointing out current problems. This study could be differentiated from the existing analyses in that it conducted comprehensive analyses on various factors that constitute urban residential environment. The conclusion of this study was derived from diverse analyses of current development condition, residential sites, regional transportation, awareness of residents, and oversee cases.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.63-72
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• 2014

The exchangeable battery electric bus is an eco-friendly public transportation vehicle. Due to the technological limitation, however, it should repeatedly change batteries with charged ones. The unmanned battery exchangeable electric bus being studied in Korea can exchange batteries automatically by using a battery swapping system. In this paper, we propose an unmanned battery exchangeable electric bus management system. The proposed system provides two services: the bus information service and the battery change scheduling service. The bus information service is the existing traditional metropolitan area bus information systems, which inform bus passengers how long they should wait for the buses. Our second service assigns a low-battery bus, which needs to change the batteries, to the battery swapping system, which stores fully-charged batteries. To validate the proposed system, we model the system by using the DEVS formalism. The simulation result shows that the proposed system provides the services properly.