• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3706-3714
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• 2011

This study deals with the algorithm to finding the maximum capacity and their schedule of extra freight while honoring planned timetable of trains on railway network. Time-expanded network, a kind of space-time graph, can be shown both planned train timetable and dynamic features of given problem. Pre-processing procedure is a series of infeasible arcs removal from time-expanded network honoring planned timetable. In the result, this preprocessing transforms dynamic features of given problem into static maximal flow problem which can be easily solved.

• Environmental and Resource Economics Review
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• v.16 no.4
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• pp.855-872
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• 2007

This study suggests an imported coal procurement model that simultaneously considers the risk factors of coal price, ocean freight rate and foreign exchange rate. In addition, it quantitatively analyses the superiority of this model compared to the previous one m terms of procurement cost saving and stabilization. According to the empirical results, a separate hedging could stabilize the procurement cost flow, but this is not the end of story. That is, a complex hedging would reduce the standard deviations of cost flow. Thus, one could improve hedging effects by fully considering the inherent variance-covariance relationship among coal price, ocean freight rate and foreign exchange.

• Journal of Navigation and Port Research
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• v.36 no.7
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• pp.591-597
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• 2012

Generally an urban freeway means a primary arterial which provides road users with a free-flow speed, except for ramp junctions during rush hours. However, most road users suffer from traffic congestion in the basic segments as well as in the ramp junctions of urban freeway during rush hours, because most road users prefer urban freeways to local roads in the urban areas. This study then intends to analyze lane traffic characteristics of urban freeway basic segments having more freight vehicles during rush hours, find the lane showing a high correlation with the segment speed between lane speeds, and finally suggest a segment-speed predictive model by the lane speed of urban freeway basic segments during rush hours.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.379-392
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• 2015

Freight flow data in Korea has been collected for a variety of purposes by various organizations. However, since the representation and format of the data varies, it has not been substantially used for freight analyses and furthermore for freight policies. In order to increase the applicability of those data sets, it is required to bring them in a table and compare for finding the differences. Then, it is shown that the raw data can be aggregated by a particular criterion such as mode, origin and destination, and type commodity. This study aims to examine the freight data issue in terms of three different points of view. First, we investigated various freight volume data sets which are released by several organizations. Second, we tried to develop formulations for freight volume data. Third, we discussed how to apply the formulations to network models in which particular OR (Operations Research) techniques are used. The results emphasized that some data might be useless for modeling once they are aggregated. As a result of examining the freight volume data, this study found that 14 organizations share their data sets at various aggregation levels. This study is not an ordinary research article, which normally includes data analysis, because it seems to be impossible to conduct extensive case studies. The reason is that the data dealt in this study are diverse. Nevertheless, this study might guide the research direction in the freight transport research society in terms of data issue. Especially, it can be concluded that this study is a timely research because the governmemt has emphasized the importance of sharing data to public throughout 'government 3.0' for research purpose.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.175-180
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• 2020

In this study, the freight vehicles were modelled and the flow analysis on the existence or non-existence of a cargo container and the wind deflector were carried out. Based on the driving speed of 100 km/hr, at all models A, B and C, the highest flow rate was shown between 58 m/s and 59 m/s at the top of the model shape. All models A, B and C showed the highest pressure of air resistance between 652Pa and 671Pa at the front of the model geometry. The maximum pressure of model A is considered to be the smallest, with the least flow resistance to speed compared to models B and C. Therefore, it can be seen that model A has an advantageous condition for air resistance in terms of fuel costs. Unlike model B which causes the rapid flow resistance at the cargo compartment, model C can be found to flow a little more smoothly on the streamlined wind deflector. So, the flow air at a streamlined shape is considered to be more advantageous in terms of air resistance than at angular shape. By applying the research analysis result on the air flow in driving according to a cargo container and the wind deflector, it is seen that this study is adequate at the practical efficient design and aesthetic convergence.

• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.304-317
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• 2016

The advancement in technology including transportation and information communication has accelerated the flow of supplies, and the importance of the national logistics policy has increased following the expansion of the regional range of logistics to a national range. The rapid growth of the domestic logistics market results in the deficit of logistics facilities, inefficient operation of logistics facilities, and a complicated distribution structure. It has precipitated a plan aimed at efficiency improvement by building base logistics facilities, but this market is now undergoing difficulties due to low performance. Many studies on the revitalization of base logistics facilities have been conducted, but a causal analysis focusing on the function overlap of private logistics businesses has been absent. Therefore, this study has analyzed the function overlap of logistics facilities and the irrationality of the system, which resulted from the lost function of Inland Freight bases in the Yeongnam region. By suggesting the cause of disuse of base logistics complexes from the function overlap in the ground transportation of domestic freight, the study can provide the policy implication for the national logistics infrastructure.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.69-74
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• 2003

This study is aimed to develop a system to position and manage object flow in real time. Logistics management system which position objects and vans using GPS is required to load, unload and keep freight effectively and in real time at sea or airport. In this study, a management system which is consisted of five sub-systems is developed; GPS position analysis system, GPS interface system, mapping system, network system and database management system.

• Asian Journal of Innovation and Policy
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• v.11 no.1
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• pp.110-147
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• 2022

Many megacities are exposed to natural hazards such as earthquakes, and when located in coastal regions, are also vulnerable to hurricanes and tsunamis. The physical infrastructures of transportation systems in megacities have become so complicated that very few organizations can understand their response to extreme events such as earthquakes and can effectively mitigate subsequent economic downfalls. The technological advances made in recent years to support these complex systems have not grown as fast as the rapid demand on these systems burdened by population shift toward megacities. The objective of this paper is to examine the risks imposed on and recoveries of transportation systems in megacities as the result of extreme events such as an earthquake. First, the physical damage to transportation infrastructure, loss of the transportation system performance, and the corresponding economic loss from disruptions to passenger and freight traffic is evaluated. Then, traffic flows are re-routed to reduce vehicles' delay due to earthquakes using a microscopic traffic flow simulator with an optimization model and macroscopic terminal simulator. Finally, the economic impact of the earthquake is estimated nationwide. Southern California is regarded as the region of study. The results demonstrate the effectiveness of the integrated model and provide what and how to prepare innovative resilience policies of urban infrastructure for a natural disaster occurrence.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.11-25
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• 2006

Space may be a scarce resource in manufacturing shops, warehouses, freight terminals, and container terminals. This Paper discusses how to locate temporary storage Inventories In limited storage areas. A typical inventory is delivered from the location of the preceding process to the storage area and stored In the storage area during the certain period of time. And it may be relocated from the storage position to another. Finally. it is delivered from the final storage area to the location of the next process. Because this logistic process for an inventory requires handling activities, transportation activities, and storage spaces, the limitation in capacities of handling equipment, transportation equipment, and storage space must be considered when allocating spaces to the inventory. This problem Is modeled as a multicommodity minimal cost flow problem. And a heuristic algorithm for the Problem is proposed. Numerical experiments are presented to validate the mathematical model and the heuristic algorithm.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.303-307
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• 2004

Is not used by consistency transport at transport of freight nothing but is using Pallet only by pedestal when work palletized unit load or materials handling when keep simplicity receptacle which fill raw material or product in factory in our country. Therefore, pallet that is most important function of Pallet is not empled circulation to end consumer from manufacturing plant which is circulation process whole path being done and factory. It is real condition stopping only in extremely determinate part process use of warehouse back. Additionally, it is possible to figure out the flow of all the materials loaded on the RFID pallet; product, material, raw material immediately, so that epoch-making management is possible and it contributes to the reduction of logistics cost because there are little loss or outflow of pallet. The materials flow is getting speedy and inventory is decreasing in the logistics process, and also bad inventory and loss problems are prevented. As a result, not only logistics cost of company but also national logistics cost is decreased. Thus it contributes to the strength of national competitiveness.