• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.11
• /
• pp.4460-4467
• /
• 2010

Recent advances in computer technology have brought more dependence on software to railway systems and changed to computer systems. Hence, the reliability and safety assurance of the vital software running on the embedded railway system is going to tend toward very critical task. Accordingly, various software test and validation activities are highly recommended in the international standards related railway software. In this paper, we presented an automated analysis tool and standard for software testing coverage in railway system, and presented its result of implementation. We developed the control flow analysis tool estimating test coverage as an important quantitative item for software safety verification in railway software. Also, we proposed judgement standards due to railway S/W Safety Integrity Level(SWSIL) based on analysis of standards in any other field for utilizing developed tool widely at real railway industrial sites. This tool has more advantage of effective measuring various test coverages than other countries, so we can expect railway S/W development and testing technology of real railway industrial sites in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.1
• /
• pp.81-91
• /
• 2019

Although the number of users of urban railways is greatly influenced by the land use plan around the railway station, Korea has been studying this problem in a small scale, so that the entrance width is uniformly calculated irrespective of the land use plan, And there is little deviation. Therefore, this study aims to establish a demand estimation model for the entrance and exit of urban railway stations. For this purpose, the demand, land use area, and socioeconomic indicators for each of the 20 urban railway stations were surveyed at 200m and 500m Regression model. The model is based on the assumption that the dependent variable (response variable) of the model is set to 1 day, peak 1 hour, peak time 5 minutes, Education, and park) and socioeconomic indicators (population, employer, employee, and student) as independent variables (explanatory variables). As a result, it was analyzed that the fit of the model is more statistically significant when the use area of the land use by 500 meters of the center radius of the city rail is used as an independent variable and the demand for the daily use of the railway station is used as a dependent variable. The purpose of this study is to estimate the optimal size of urban railway entrance in order to improve the mobility of the user and the transportation weak in urban railway station.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.1
• /
• pp.85-91
• /
• 2021

In contrast to standard train tracks, tramlines are often set along public roads, with trams running among pedestrians and other vehicles. In some cities and towns, trams and buses share the same routes and stations. Under the current investment appraisal system, trams are classified into light rail when predicting traffic demand and calculating benefits, but in the case of non-capital areas, it is notable that the origin-destination and transit lines of buses are not provided in the Korea Transport Database distribution data. Due to this problem, it is difficult to reflect proper mode changing behaviors between route buses and trams. This study examines the impact on tramlines of bus routes that are not currently considered in non-capital areas. Following an analysis of the effect of tram projects according to whether bus routes are considered or not, an improvement in methodology is proposed. Through this study, it is expected that the investment appraisal system for the planning of new tramlines will be improved in the future.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.9
• /
• pp.1172-1179
• /
• 2020

With the establishment of the railway integrated radio network (LTE-R) environment, radio-based train control transmission and reception and various forms of service are provided. The smooth delivery of these services requires improved performance in a highly reliable and available wireless environment. This paper measured the LTE-R radio communication environment to improve radio communication performance of railway integrated wireless network reliability and availability, analyzed the results, and established the wireless environment model. Based on the built-up model, we also proposed an improved radio-access algorithm to control trains for improved reliability, suggesting a way to improve stability for handover that occur during open-air operation, and proposed an algorithm for frequency auto-heating to improve availability. For simulation, data were collected from the Korea Rail Network Authority (Daejeon), Manjong-Gangneung KTX route, which can measure the actual data of LTE-R wireless environment, and the results of the simulation show performance improvement through algorithm.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.12
• /
• pp.5-12
• /
• 2008

The reinforced earth wall, which is able to improve the strength of soil highly, is required in case of supporting high surcharge load such as high speed rail way, high embankment road, and massive reinforced earth wall in a mountainous area. And also, it is continuously required that the method is able to minimize the amount of excavated soil on account of environmental issue, boundary of land, etc., on excavation site. However, because the required length of reinforcement should be $60{\sim}80%$ of the height of reinforced earth wall for general reinforced earth wall, in fact the reinforced earth wall is hardly applied on the site of cut slope. In this paper we studied the design and construction cases of hybrid reinforcement retaining wall system combined with steel strips and soil nails, connecting the reinforced earth wall reinforcements to the slope stability reinforcements (soil nails) to ensure sufficient resistance by means of reducing the length of reinforcements of reinforced earth wall. And the feasibility of hybrid reinforcement retaining wall system, suggested by real data measured on site, is also discussed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.4D
• /
• pp.679-686
• /
• 2006

Recently, the city railway in the Seoul Metropolitan Area (SMA) has offered a low quality of service as a passage time, because it was operated slowly. So, the people who live in modern society are not satisfied about passage time, therefore, this study tried to make that the subway in the SMA becomes a more functional and effective wide-area-transportation-network through an express train introduction's method which examined cases from abroad and current system. and then presented how express train could be applied to current system. In a case study, We used the An-San Line and Su-In Line as a examples and developed a schedule which can minimize the delaying time of subway by using Branch & Bound Algorithm. The train operational plan was loaded to consider a railroad siding, Obtained site, and the dispatch interval(three to ten minutes) for the express and local lines and finally, We presented an alternative operational plan which made by those factors.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5D
• /
• pp.477-483
• /
• 2010

The existing mass transport system, with its limited capacity and the saturated road networks, has given cause for a new means of transport to be developed, and strong demands for such new means of transport are observed more than ever. However, the traffic authority is seeking a new transport system that focuses more on LRT(Light Rail Transit), a downsized version of the existing urban railroad, rather than one that is appropriate to solve the traffic problems. Moreover, local governments are experiencing difficulties in planning their own mass transportation(bus or urban railroad) as they have no specified criteria for selecting a mass transport system. Accordingly, there has been an increasingly loud voice that calls for criteria to determine which mass transport system befits each transportation corridor. This paper develops a mass-transport demand forecasting model based on the GIS Buffering analysis of each transportation corridor in the city, sets up the capacity for each mass transport system and presents the criteria for selecting an optimal mass transport system for each transportation corridor. It also presents a methodology that identifies necessary and sufficient conditions for selection and evaluation, since it is most important to select the optimal mass-transport system that can meet the demand by each mass-transportation corridor.

• Journal of the Korean Society for Railway
• /
• v.20 no.1
• /
• pp.85-98
• /
• 2017

In general, under the repetitive dynamic load generated by rail cars running on the track, subgrade soil experiences changes of stress conditions such as deviatoric stress (${\sigma}_d$) and bulk stress (${\theta}$). Due to the repetitive change of deviatoric stress (${\sigma}_d$) with number of loadings, the resilient modulus ($M_R$) can be obtained by using the measured resilient strain (${\varepsilon}_r$) after a sufficient number of loadings. At present, no plausible and unified test method has been proposed to obtain the resilient modulus of railway track subgrade soil. In this study, a possible test method for obtaining the resilient modulus ($M_R$) of railway track subgrade soil is proposed; this test, by utilizing repetitive triaxial compression testing, can consider all the important parameters, such as the confining stress, deviatoric stress, and number of loadings. By adapting and using the proposed test method to obtain $M_R$, $M_R$ values for compacted track subgrade soil can be successfully determined using soil obtained in three field sites of railway track construction with changing water content range from OMC. In addition, shear modulus (G) ~ shear strain (${\gamma}$) relation data were also obtained using a mid-size RC test. A correlation analysis was performed using the obtained G and $M_R$ values while considering the strain levels and modes of strain direction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3632-3637
• /
• 2009

In this paper, we describe the performance results of the field installation test which is required to practicalize the single-phase MJ81 Switch Point Machine. This product has passed the certified test through performance improvement of driving parts in order to use 3 phase MJ81 Switch Point Machine, which is localized by taking over technology from Alstom and Cogifer when constructing Seoul-Busan rapid-transit railway, without change of the electrical equipment at track-side in domestic existing lines which single-phase 220V is used. KRRI and Samsung SDS have localized the single-phase MJ81 Switch Point Machine to improve the speed and safety of the conventional lines through the existing railway technology development project. For practicalization of this, we should, however, verify the performance through not only field installation test in real lines but also interface test with the interlocking. In this paper we verify the practicality of the domestic single-phase MJ81 Switch Point Machine through analysis on the performance result of the field installation test as well as the research contents for this test. Thereby, in Feb 2009 we have received an order from the Korea Rail Network Authority and are currently installing the single-phase MJ81 Switch Point Machine.

• Asian Journal of Atmospheric Environment
• /
• v.4 no.2
• /
• pp.97-105
• /
• 2010

A quantitative single particle analytical technique, denoted low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), was applied to characterize particulate matters collected at two underground subway stations, Jegidong and Yangje stations, in Seoul, Korea. To clearly identify the source of the indoor aerosols in the subway stations, four sets of samples were collected at four different locations within the subway stations: in the tunnel; at the platform; near the ticket office; nearby outdoors. Aerosol samples collected on stages 2 and 3 ($D_p$: $10-2.5\;{\mu}m$ and $2.5-1.0\;{\mu}m$, respectively) in a 3-stage Dekati $PM_{10}$ impactor were investigated. Samples were collected during summertime in 2009. The major chemical species observed in the subway particle samples were Fe-containing, carbonaceous, and soil-derived particles, and secondary aerosols such as nitrates and sulfates. Among them, Fe-containing particles were the most popular. The tunnel samples contained 85-88% of Fe-containing particles, with the abundance of Fe-containing particles decreasing as the distances of sampling locations from the tunnel increased. The Fe-containing subway particles were generated mainly from mechanical wear and friction processes at rail-wheel-brake interfaces. Carbonaceous, soil-derived, and secondary nitrate and/or sulfate particles observed in the underground subway particles likely flowed in from the outdoor environment by human activities and the air-exchange between the subway system and the outdoors. In addition, since the platform screen doors (PSDs) limit air-mixing between the tunnel and the platform, samples collected at the platform at the Yangjae station (with PSDs) showed a marked decrease in the relative abundances of Fe-containing particles compared to the Jegidong station (without PSDs).