• International Commerce and Information Review
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• v.15 no.2
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• pp.3-23
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• 2013

In 1997, 180 countries signed the Kyoto Protocol in Kyoto, Japan. The Kyoto Protocol came into force in February 2005. The agreement calls for industrialized nations to cut greenhouse gas emissions by 5 percent from 1990 levels by 2008 to 2012. One of those polices is a modal shift that change from road freight to sea, inland waterway and railroad transportation that is eco-friendly. The increase of road freight brings road congestion, accidents, logistic costs, air pollution and greenhouse gases. Railroads are superior than the other modes of transportation in mass transportability, high speed, timeliness, safety and environmental-friendliness, but the railway industry has been pushed behind in competition. Korean railroads were used by passengers and freight transport popularly until the middle of 20th century, however, by the sudden change of logistics environments, a shaving time efficiency being most important, railroad logistic lost its competitive power against the transportation by truck. From the research which sees consequently investigated a various policy, a system and a law about Chinese logistics industry and present condition of the Chinese goods enterprise and instance analysis of the large Chinese corporation that branch out to undeveloped markets led and a Chinese logistics industry and problem point escape hereafter the heightening of competitiveness plan which is rational under prsenting boil.

• The Journal of Engineering Geology
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• v.30 no.1
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• pp.43-57
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• 2020

The objective of this study was to evaluate the performance of high-strength lattice girders as a possible superior alternative to conventional steel arch ribs. For this purpose, the structural characteristics of supports were analyzed using numerical analysis, and their performance was evaluated using maximum bending load tests and tensile tests of the welded joint. According to the results of structural analysis, the optimum size of the upper and lower members and plates is 50 mm × 31.8 mm × 25.4 mm, demonstrating excellent functionality and economic efficiency. High-strength lattice girders of dimensions 55 mm × 30 mm × 20 mm and 85 mm × 30 mm × 20 mm, determined from bending load tests, are found to meet both the reference values and the target values of H-profiles 100 and 125. A review of the ratio of theoretical deflection to actual deflection shows that the high-strength lattice girder developed during this study meets fewer than five of the evaluation criteria for lattice girder deflections proposed by the Federal Railway Department of Germany. Finally, tensile test results reveal that the welded joint of the high-strength lattice girder at the main steel bar-auxiliary steel bar-plate junction exceeds the target value, indicating that the welded joint has sufficient stability.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.69-78
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• 2004

In this study, the back analysis program was developed by applying the genetic algorithm, one of artificial intelligence fields, to the direct method. The optimization process which has influence on the efficiency of the direct method was modulated with genetic algorithm. On conditions that the displacement computed by forward analysis for a certain rock mass model was the same as the displacement measured at the tunnel section, back analysis was executed to verify the validity of the program. Usefulness of the program was confirmed by comparing relative errors calculated by back analysis, which is carried out under the same rock mass conditions as analysis model of Gens et at (1987), one of back analysis case in the past. We estimated the total displacement occurring by tunnelling with the crown settlement and convergence measured at the working faces in three tunnel sites of Kyungbu Express railway. Those data measured at the working face are used for back analysis as the input data after confidence test. As the results of the back analysis, we comprehended the tendency of tunnel behaviors with comparing the respective deformation characteristics obtained by the measurement at the working face and by back analysis. Also the usefulness and applicability of the back analysis program developed in this study were verified.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.3
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• pp.50-62
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• 2015

Recently, Subway Line No. 9, described as a 'hell-like' subway for its recorded load factor of max. 240% due to the opening of the 2nd phase extension section, has been causing problems of recurrent congestion in a subway station building. A recurrent congestion in the station building becomes a factor to offend rail users and to reduce the efficiency of railway management. This study aims to establish the methodology for effect evaluation of information provided to rail users, and conducts a gate metering case study considering the congested conditions at a platform among the methodologies for effect evaluation. The metering effect evaluation by load factor was conducted through selecting the micro simulation and pedestrian simulation tool grafting a gate metering. As a result, it was confirmed that, if gate metering is performed, the service level and pedestrian density of a platform by load factor would improve. In other words, if metering is conducted at a platform, it is possible to control the load factor in the waiting space of a platform. Therefore, it was judged through this study that it is possible to set up the index for effect evaluation of information provided to manage congestion of rail users, and establish the methodology for effect evaluation of information provided to rail users through a program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.351-358
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• 2016

An Electrical Point Machine (NS:New-type Switch), which is equipped and operated at railways in Korea, has been used since the 1960s after being imported from Japan. On the other hand, although the mechanical configuration has improved the position motor control circuit, the electrical connection has not been improved, so NS may have a problem, such as the interlocking system of automatic train operation. In addition, NS is the most vulnerable part in the railway system and a huge train accident may occur due to minor defects. The existing NS wiring set of the circuit controller should be checked only if fixed. Therefore, an excessive inspection time only by a Railroad Signal expert is required. In this paper, the improvement of electrical connection in a NS wiring set, such as the position motor control circuit, was developed and the prototype was installed at Seoul Metro in the distance to go section. The results can be used to help make appropriate adjustments. The improvement of the NS wiring set enhance the maintenance efficiency, passenger service and the stability of the signal system as well as reducing the maintenance cost.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.87-92
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• 2011

This paper describes a study on the permeability reduction of the riverbed ground during urban railway tunnel construction. The research is mainly concentrated on the study of the grouting or injection methods among permeability reduction methods which can be adapted in the riverbed ground. The design technology of grouting methods considering the long term hydro-geological behaviour in the riverbed, was suggested. Two injection methods namely, Natural Durable Stabilizer (N.D.S) and Space-Multi Injection Grouting (S.M.I) methods, were introduced as new approach methods which could be adapted to modify the riverbed ground. In order to evaluate the performance of the improved ground by the N.D.S and S.M.I method, a series of pilot tests including the field and laboratory permeability tests, were carried out in the river crossing tunnel construction sites. The results obtained from pilot test program, were also reviewed. The results, the grouting efficiency of the S.M.I method using the non-alkalimeter silica sol is better than that of N.D.S method using cement. In addition, it is anticipated that the current research results are contributed to develop the grouting design technology.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.379-390
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• 2022

While the construction industry is striving to make changes suitable for the 4th industrial revolution era through the introduction of 4th industrial revolution technologies, such change is progressing more slowly than in other industries. Nevertheless, the recent digitization and digital transformation of the construction industry can provide a new paradigm to address and innovate the chronic problems faced by the construction industry. Therefore, in this study, a case study using a data hub and API for use of the data hub, which is essential for digitalization and digital transformation, was conducted, and the efficiency and feasibility of using the data hub and API were considered. When the API system was introduced, it was found that the average budget savings per person was about 23%, and the costbenefit ratio was about 4.4 times higher, indicating that the feasibility of the project was very high. The results and framework of this study can serve as fundamental research data for related research, and provide a worthy case study to promote the introduction of related technologies. This will ultimately contribute to digitalization and digital transformation for smartization of the construction industry.

• Steel and Composite Structures
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• v.48 no.2
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• pp.207-233
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• 2023

Steel-concrete composite box girder bridges are widely used in the construction of highway and railway bridges both domestically and abroad due to their advantages of being light weight and having a large spanning ability and very large torsional rigidity. Composite box girder bridges exhibit the effects of shear lag, restrained torsion, distortion and interface bidirectional slip under various loads during operation. As one of the most commonly used calculation tools in bridge engineering analysis, one-dimensional models offer the advantages of high calculation efficiency and strong stability. Currently, research on the one-dimensional model of composite beams mainly focuses on simulating interface longitudinal slip and the shear lag effect. There are relatively few studies on the one-dimensional model which can consider the effects of restrained torsion, distortion and interface transverse slip. Additionally, there are few studies on vehicle-bridge integrated systems where a one-dimensional model is used as a tool that only considers the calculations of natural frequency, mode and moving load conditions to study the dynamic response of composite beams. Some scholars have established a dynamic analysis model of a coupled composite beam bridge-train system, but where the composite beam is only simulated using a Euler beam or Timoshenko beam. As a result, it is impossible to comprehensively consider multiple complex force effects, such as shear lag, restrained torsion, distortion and interface bidirectional slip of composite beams. In this paper, a 27 DOF vehicle rigid body model is used to simulate train operation. A two-node 26 DOF finite beam element with composed box beams considering the effects of shear lag, restrained torsion, distortion and interface bidirectional slip is proposed. The dynamic analysis model of the coupled composite box girder bridge-train system is constructed based on the wheel-rail contact relationship of vertical close-fitting and lateral linear creeping slip. Furthermore, the accuracy of the dynamic analysis model is verified via the measured dynamic response data of a practical composite box girder bridge. Finally, the dynamic analysis model is applied in order to study the influence of various mechanical effects on the dynamic performance of the vehicle-bridge system.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.75-89
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• 2024

As the problem of lowering the efficiency of urban services in small and medium-sized cities in the non-metropolitan area intensifies, the necessity of developing a railway station area is being emphasized to form a compressed urban space through regional bases. Although major station areas in large cities are being developed in the form of complex, the analysis of the development location characteristics of the small and medium-sized city station areas is insufficient. The purpose of this study is to analyze the characteristics of development project conditions and potential demand in the high-speed rail station areas across the country, identify the differences in locational characteristics according to the type of city, such as 'metropolitan city', 'large city in non-metropolitan city', 'medium and small city in non-metropolitan city', and find out the appropriate development method. As a result of the analysis, it was analyzed that the 'metropolitan area metropolitan area' has high potential demand and poor business conditions. On the other hand, in the case of the non-metropolitan area, it was analyzed that the 'small and medium-sized city station area' has good business conditions and low potential demand characteristics, and the 'large city station area' has intermediate characteristics. This suggests the need for different development methods in the development of metropolitan and small and medium-sized city station areas. The analysis results of this study show that it is desirable to encourage private participation in large-scale metropolitan station areas, which require large-scale input, to maximize potential demand, and to encourage private participation through public-led projects based on favorable business conditions or development based on regional characteristics.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.127-144
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• 2021

The purpose of this study is to derive service factors based on the "Rail Statistical Yearbook" data of railroad service providers from 1990 to 2019, and to analyze the effect of the service factors on the operating profit ratio(OPR), a representative management performance variable of railroad transport service providers. In particular, it has academic significance in terms of empirical research to evaluate whether the management innovation of the KoRail has changed in line with the purpose of establishing the corporation by dividing the research period into the first period (1990-2003) and the latter (2004-2019). The contents of this study investigated previous studies on the quality of railway passenger transportation service and analyzed the contents of government presentation data related to the management performance evaluation of the KoRail. As an empirical analysis model, a research model was constructed using OPR as a dependent variable and service factor variables of infrastructure, economy, safety, connectivity, and business diversity as explanatory variables based on the operation and management activity information during the analysis period 30 years. On the results of research analysis, OPR is that the infrastructure factor is improved by structural reform or efficiency improvement. And economic factors are the fact that operating profit ratio improves by reducing costs. The safety factor did not reveal the significant explanatory power of the regression coefficient, but the sign of influence was the same as the prediction. Connectivity factor reveals a influence on differences between first period and latter, but OPR impact direction is changed from negative in before to positive in late. This is an evironment in which connectivity is actually realized in later period. On diversity factor, there is no effect of investment share in subsidiaries and government subsidies on OPR.