• Proceedings of the KOR-KST Conference
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• 2007.05a
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• pp.527-535
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.379-389
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• 2022

The number of public transportation users has dropped drastically due to COVID-19. In this work, my survey was conducted to uncover the factors that influence citizens' travel patterns. Data were collected and logistic regression analysis on the shifts in transportation was undertaken. Additionally, an importance-performance analysis was carried out to investigate how to effectively operate public transportation systems and improve facilities. The main research findings were as follows: First, the more individuals were concerned about COVID-19 (+) and being infected when using public transportation (+), the greater the tendency to switch to private transportation modes. Secondly, when it came to personal traits, respondents who could drive a car (+) or owned a car (+)or did more online shopping (+) or used public transportation for trips (+) tended to switch over, compared with respondents who could not drive or did not own a caror used public transportation to commute. In addition, respondents who were vaccinated (-) or had more household members tended not to switch transportation modes, compared with those who were not vaccinated or had fewer household members. Third, it is important to continue the following efforts to safeguardhygiene linked to public transportation: wearing masks, disinfecting hands, controlling diseases, and general cleaning. The conclusion was that it is important to put traffic congestion and ventilation issues first, especially in regards public transportation, which was not rated as satisfactory enough compared to its importance. The research findings can provide useful basic data when establishing countermeasures to the current COVID-19 circumstances in the areas of public transportation operation and management and in the event of an infectious disease outbreak in the future.

• International Journal of Railway
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• v.5 no.3
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• pp.117-123
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• 2012

According to the Intergovernmental Panel on Climate Change, combustion of petroleum-based and other fossil fuels results in the increasing atmospheric concentrations of $CO_2$ and other greenhouse gases (GHG's) and is a major contributing factor to global warming. This paper includes estimates of the energy and petroleum use and the GHG emissions caused by the transportation sector. It then examines the extent to which diversions to alternative modes may be possible. Estimates are made of the potential reductions in energy and petroleum use and GHG emissions resulting from diversions from conventional modes, to both low-speed urban and high-speed intercity maglev vehicle trips based on "well-to-wheel" (i.e. total-fuel-cycle) calculations.

• Structural Engineering and Mechanics
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• v.65 no.4
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• pp.389-400
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• 2018

An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.52-58
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• 2013

This study discusses how transportation to connect railway stations in Korea's small and medium-sized cities can be improved, based on analysis of a survey on the Joongang Line. The analysis considered current problems in connectivity between parts of the Korean transportation system and suggests how to encourage more passengers to shift from private cars to railways. It was found that railway users in small and medium-sized cities hope for better connection between different modes of public transportation, especially for urban buses. However, there is not enough connectivity currently available; therefore it is crucial to establish a system of such connections, mainly focusing on urban buses. Furthermore, in order to minimize transfer distances and connect various transfer modes, plans for improvements of facilities are needed and governmental support should be provided.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.41-46
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• 2011

The port of Busan is the fifth busiest container port in the world in terms of total mass of 20-foot equivalent units transported. Yet no attempts have been made to estimate the greenhouse gas (GHG) emissions from the port of Busan by accounting for all port-related activities of the various transportation modes. With these challenges in mind, this study estimates the first activity-based GHG emissions inventory in the port of Busan, which consists of four transportation modes: marine vessels, cargo-handling equipment, heavy-duty trucks, and railroad locomotives. The estimation results based on the most recent and complete port-related activity data are as follows. First, the average annual transportation GHG emission in the port of Busan during the analysis period from 2000 to 2007 was 802 Gg $CO_2$-eq, with a lower value of 773 Gg $CO_2$-eq and an upper value of 813 Gg $CO_2$-eq. Second, the increase in the transportation-related GHG emissions in the port of Busan during the analysis period can be systematically explained by the amount of cargo handled ($R^2$=0.98). Third, about 64% of total GHG emissions in the port of Busan were from marine vessels because more than 40% of all maritime containerized trade flows in the port were transshipment traffic. Fourth, approximately 22% of the total GHG emissions in the port of Busan were from on-road or railroad vehicles, which transport cargo to and from the port of Busan. Finally, the remaining 14% of total GHG emissions were from the cargo handling equipment, such as cranes, yard tractors, and reach stackers.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.76-82
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• 2019

This study was investigate the characteristics of GHGs ($CO_2$, $CH_4$, and $N_2O$) emissions of diesel medium duty trucks according to their various driving modes. GHGs emissions decreased as vehicle speed increased, and emissions increased after 64.7 km/h. The 4.5 ton trucks show higher values of $CO_2$, $CH_4$, $N_2O$, 35%, 25%, and 57%, respectively, comparing of the 2.5 ton trucks. Also, $CO_2$ emissions under WHVC mode were 20% lower than those under the NEDC mode. In the case of cold start condition, $CO_2$ emissions were 12-13% higher than those for hot start condition. In the future, the result of present study will provide basic data to set up GHGs emission standards for medium and heavy duty vehicles.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2303-2308
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• 2010

We studied the cost-volume supply characteristic of public transportation systems focused on Bi-modal Tram in the main cities to analyze the applicability and status for the new transit system Bi-modal Tram as public transportation system. The operation cost considering the characteristic of vehicle, facilities, operation and average cost for respective public transportation system and the time cost considering the travel and transfer time are defined to the social cost, and the cost-volume supply curve is based on this social cost. The cost-volume supply characteristic between public transportation modes in the city is determined on the basis of cost-volume supply curve. Through the comparison between cost-volume supply characteristic of main transportation systems, it is analyzed about the relation between public transportation systems in the city and the characteristic for proper service provision. The application of Bi-modal Tram in the city is concluded that it is effective to reduce the social cost on the existing public transportation system.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.290-299
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• 2002

The Korean railroads' logistics are facing the important turning points by the connection of. South and North Korean railroads, and the commercial opening of the High Speed Rail. These two factors demand several plans for the development of railroads' logistics, in which intermodal transportation with the others modes is wholly studied. In this respect the case of port of Hamburg, Germany, where railroads are completely integrated in the port, will permit the Koreans some useful lessons for the future of railroads' logistics.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.7-14
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• 2000

The purpose of this study is to improvement strategies for transportation systems of container cargo in Busan port. Therefore, it was forecasted the future container cargo demand using logistic curve formula. In 2011, container cargo demand was forecasted 8.791 million TEU(T/S including 12.559 million TEU). In order to improvement transportation systems of container cargo, this study presented following; $\circled1$ port facilities expansion, $\circled2$ diversity of container transport modes. $\circled3$ make up ICD and exclusive container roads, $\circled4$ the second Seoul-Busan Expressway.