• Journal of the Korean Society for Railway
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• v.6 no.3
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• pp.169-173
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• 2003

Transportation by railroad is superior to other transport in a mass transport, stability, rapid transit, delightfulness and low-pollution etc. But, it need to ensure a track stability that supports the train-load for high-speed in transportation by railroad. Ballast resistance force resists against the buckling of track taking a rail-tie's place. So, it plays an important role in a careful train-service. So, in this papers, we forced on measuring and theorizing about the Ballast Resistance Force that play a key role in track stability and high-speed. And we studied the mechanical property. Finally, we suggested the method of securing Ballast Resistance Force and the report for a careful train-service in high-speed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.395-402
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• 2008

Aggregate bandwidth required by the internet is expected to be explosively increased. To meet this anticipated need, an ultra high speed internet backbone transport network, capable of supporting up to a Tbps traffic capacity, is required. this thesis examines, through computer simulation and modeling, the technological requirements and assesses the performance analysis and feasibility for implementing ultra-high speed NGI backbone transport network fabric based on WDM technology. The study results are that C/L band EDFA spectral gains for ultra high speed DWDM have been improved from 2.61dB/1.5386dB to 0.03dB/0.096dB by proposed architecture.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.33-42
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• 2010

Travel speed is an important parameter in measurement of road traffic. UTIS(Urban Traffic Information System) was developed as a type of section detector. However, UTIS incur errors caused by irregular vehicle trajectories, wireless communication range and so on. This paper suggests a new model that use an error-filtering algorithm to improve the accuracy of travel speed measurements. In the field test, the variance of the percent errors measured by the new model was reduced. Therefore, it can be concluded that the proposed model significantly improves travel speed measuring accuracy.

• Journal of Korea Port Economic Association
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• v.22 no.3
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• pp.189-207
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• 2006

As the development of Northeast Asian logistics hub becomes one of the national agenda for further development, the sea&Air transport around the Yellow Sea regions has drawn attention of many scholars and government officials. The Sea&air transport is a mode of transportation combining the advantage of high-speed in air transport with the advantage of low-price in sea transport. Hence the sea&air aims at a niche market between air and sea. This paper reviews the possibility of development of the sea&air transport in the aspects of competitiveness over other modes, future demand condition, and the change of the technology and transport environment. The result is that the sea&air is competitive in the aspect of time as well as cost, and sustainable in the aspect of future demand condition. But, it is not stable in the aspect of the conditions of technology or transport demand. Especially, the progress of air transport technology which is aiming at the door-to-door transport among mid- and small- cities, and the rapidly increasing strategic alliances of international airlines with Chinese airlines for the market of China will undermine the stability of the sea&air transport seriously As alternatives, this paper proposes the 3-stage development strategy of sea&air transport. First, at the stage of transshipement, the development of high speed vessels to reduce the time crossing the Yellow Sea and the proactive marketing strategy to induce Chinese-owned products should be emphasized. Second, the value added logistics activity which will secure the demand of the sea&air transport should be developed. Third, demand creation by developing the SCM hub in Incheon is final goal for the logistics hub strategy as well as the sea&air transport.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.16-26
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• 2011

Variable speed limit(VSL) is one of the highway ITS techniques designed to prevent accidents and traffic slow down by reducing congestion or speed variation between vehicles and lanes prior to arrive at the accident location by limiting speed. In Korea, while people have recognized the need for variable speed limit beginning with Seoul's urban expressway and installed facilities in order to provide guide for speed limit per lane and lane use, there has not been enough development of algorithm for internal administration as well as research on the basic principles behind administering variable speed limit. This study is for modeling and evaluating the VSL strategies based on the traffic flow theory. Supply-Demand method of the Cell Transmission Model is applied to demonstrate the traffic features and shockwaves to upstream of the bottleneck with/without VSL. We verified the explanation of Cell Transmission Model for the numerical example. and as the result, it is found that VSL strategies can reduce the total travel time in the congested section and variation of the speed. It means VSL is useful to improve the traffic condition and the safety on highway

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.74-84
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• 2022

Vehicle average speed information which measured at a point or a short section has a problem in that it cannot accurately provide the speed changes on an actual highway. In this study, segment separation method based on vehicle big data for accurate micro-speed estimation is proposed. In this study, to find the point where the speed deviation occurs using location-based individual vehicle big data, time and space mean speed functions were used. Next, points being changed micro-scale speed are classified through gradual segment separation based on geohash. By the comparative evaluation for the results, this study presents that the link-based speed is could not represent accurate speed for micro-scale segments.

• Journal of Korea Port Economic Association
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• v.17 no.2
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• pp.1-28
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• 2001

Korea has been at the forefront of efforts to enhance international cooperation in transport and communications within Northeast Asia. This effort is driven not only by the benefits that could accrue to the Korean Peninsula but also to all nations in the region. Mutual cooperation within Northeast Asia would reduce transport and communications costs and provide the basis for a regional transport and logistics network. Before progress can be made towards an integrated transport and communications system in Northeast Asia, however, there is a need to evaluate its prospects, outline a visionary plan, and detail a preferred strategy. The strategy to develop the Korean Peninsula as the gateway for Northeast Asia should harmonize with the region's common transport (and communications) policy The strategy adopted by South Korea is focused primarily on the development of an improved logistics infrastructure that would be extended to North Korea upon reunification. The seaport and airport developments In Korea will have to be supported by improved access to planned high-speed railways, expressways and freight distribution centers that, in turn, are to be integrated with new telecommunications and computer technologies. The benefits from these improvements will be lost unless existing government monopolies controlling seaport, airport, rail, road and expressway developments are commercialized to ensure that the price of transport reflects its actual cost. Technical harmonization between different modes should be promoted to facilitate efficient intermodal transport between the Korean Peninsula and the rest of Northeast Asia.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.194-201
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• 2018

Purpose: The objective of this study was to propose a formula for the theoretical grain mean transport velocities of an elliptically moving oscillator by modifying the grain mean transport velocity formula applied to linear motion and to compare the calculated values with the experimental values of grain mean transport velocity. Methods: The values of the throwing index ($K_v$) and the maximum horizontal velocities for various positions on the elliptical oscillator were obtained using kinematic analysis. To obtain the actual grain transport velocity, the mean transport velocities of perilla grains at six positions on the sieve surface were measured using a high-speed camera and compared with the theoretical values. The cam with an eccentric bearing on the oscillator was designed to be eccentric by 1.6 cm so that the lengths of the major axis of the elliptical motion were 3.2-3.6 cm. The material used in the experiments was perilla grain. Results: The experimental result was consistent with the theoretical value calculated using the proposed formula ($R^2$ is 0.80). It is considered that the angle difference between the maximum accelerations in the directions vertical and horizontal to the sieve has as much influence on the grain mean transport velocity as the value of Kv itself. Conclusions: It was possible to theoretically obtain the grain mean transport velocities through a screening device in elliptical motion by modifying the formula of the grain mean transport velocities used in linear motion.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1889-1907
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• 2014

The characteristics of meteorological conditions related to changes in atmospheric environment on Jeju Island were investigated during recent years (2010-2012). This analysis was performed using the hourly observed data of meteorological variables (air temperature, wind speed and direction) and air pollutants ($O_3$, $PM_{10}$, $SO_2$, $NO_2$, and CO). Out of 5 pollutants, $O_3$ and $PM_{10}$ concentrations have frequently exceeded national environmental standards in the study area during the study period, with relatively higher concentrations than the others. The concentrations of $O_3$ and $PM_{10}$ in 2010 and 2011 were somewhat higher than those in 2012, and their highest concentrations were mostly observed in spring followed by fall. Nighttime $O_3$ concentrations (with relatively high concentration levels) were almost similar to its daytime concentrations, due to less $O_3$ titration by very low NO concentrations in the target area and in part to $O_3$ increase resulting from atmospheric transport processes. The transport effect related to the concentration variations of $O_3$ and $PM_{10}$ was also clarified in correlation between these pollutants and meteorological variables, e.g. the high exceedance frequency of concentration criteria with strong wind speed and the high concentrations with the westerly/northwesterly winds (e.g., transport from the polluted regions of China). The overall results of this study suggest that the changes in atmospheric environment in the study area were likely to be caused by the transport effect (horizontal and vertical) due to the meteorological conditions rather than the contribution of local emission sources.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.40-51
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• 2020

Much time has passed since Korea's expressway congestion-threshold speed was revised in 2011. In the meantime, various expressway environments have changed owing to improved performance of vehicles, expanded operations of transport competition (i.e., the KTX), and increased speed limits along some expressway sections. In addition, the speed that expressway users expect to travel at is also increasing. Therefore, through a survey, this study investigates expressway users' perceptions of congestion, and reviews the adjustment of the expressway speed congestion threshold by analyzing expressway traffic flow. One result of the survey confirms that the threshold speed expressway users consider to be congestion has slightly increased. Analyzing traffic and speed data through a K-means algorithm found that the threshold speed for congestion is 60 km/h. In addition, assuming the congestion threshold speed increase from 40 km/h to 50 km/h and 60 km/h, frequently congested expressway sections are identified, determining that 50 km/h is appropriate as a congestion threshold for proper expressway mobility management.