• Journal of the Korean Society for Railway
• /
• v.12 no.1
• /
• pp.45-54
• /
• 2009

TETRA(Terrestrial Trunked Radio) is the standard of D-TRS(Digital Trunked Radio System) developed by the ETSI(European Telecommunications Standards Institute). Currently, TETRA has been selected as Electric Power IT Wireless Backbone Network. Traditional distribution automation system has used the wireless network of Mobile Service Provider using CDMA(Code-Division Multiple Access) and WCDMA(Wideband CDMA) modem. Therefore, the development of gateway platform is indispensable according to the change to TETRA network. In this paper, we propose an embedded Linux-based Gateway platform for transmitting Industrial Electric Power IT protocol using TETRA network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.527-530
• /
• 2017

LTE-R(Long Term Evolution-Railway) based on LTE technology is expected to use core communication technology for high speed railway as one of standards for railway communications. In this paper, transmission performance of video traffic as an application is analyzed on LTE-R networks. Performance is evaluated with compter simulation based NS(Network Simulator)-2, open video traffic is used, RTP(Real Time Protocol) is used for transmission protocol. Results and methods of this paper can be used for research and developmemt of LTE-R networks.

• Journal of the Korean Society for Railway
• /
• v.9 no.3 s.34
• /
• pp.313-318
• /
• 2006

In this paper, we propose an efficient Care of Address (CoA) configuration scheme for network mobility support in the railroad environment. Mobile routers in a train visit each access router in the fixed order. Such regular movement characteristic of a train enables a current subnet access router to inform the next subnet access router of the mobile routers' interface identifiers before the mobile routers move to the next subnet access router. So, the next subnet access router can make care of addresses for the mobile routers in advance. The numerical results show that the proposed scheme outperforms the stateless scheme with respect to CoA configuration time.

• Journal of the Korean Society for Railway
• /
• v.20 no.1
• /
• pp.142-155
• /
• 2017

It is anticipated that, in cases in which different train operators share railway network, conflicts may occur among train operators with regard to train operation rate, train priorities, and arrival and departure time; besides this, during times when there is high demand for trains, operators will request train operations intensively, steadily increasing train conflict phenomena. In the present study, train operation sequence, minimum headway, arrival and departure time, train priorities, etc., were analyzed, and while using train departure times as decision variables in variably given train schedules, by adjusting train time requested by train operators, and finally rejecting the train times in cases in which conflict resolution is impossible, so that various constraints can be satisfied, a train slot allocation model was suggested to find the objective function, that is, the maximum number of train slots that can be practically applicable to railway operation.

• Ecology and Resilient Infrastructure
• /
• v.5 no.1
• /
• pp.45-53
• /
• 2018

Ecological networks can be generally classified into core areas, buffer zones, and corridors. Particularly, buffer zones connect core areas or ecological corridors, and preserve ecological network by reducing the impact from outside. We examined related laws and researches about buffer zone establishment associated with the resources of high ecological and conservation value to find out more researches are needed. In this study, we investigated various examples of the criteria for establishing buffer zones at domestic and overseas. Based on the results of railway environmental impact assessment and railway construction guidelines, we analyzed the application methods applicable to the railway development area and proposed the criteria to evaluate land cover status, species diversity, rarity, and connectivity. Through this study, the environmental and ecological value around the development area of the railroad was examined to reduce the environmental damage from railroad construction.

• Journal of the Korean Society for Railway
• /
• v.19 no.3
• /
• pp.363-372
• /
• 2016

This study identifies influence factors for Korean railway export and analyzes the importance and competitiveness of the factors. This study also suggests policy directions for each factor and analyzes the current situation of the Korean railway industry. All influence factors identified in this study turned out to have high levels of importance. Influence factors with higher importance levels for each field are as follows: man-power/experience and skill/technology in the engineering field; price, information and man-power/experience in the construction field; and information, technology, and price in the manufacturing field. However, the level of competitiveness of the factors turned out to be low. This study also suggested policy directions for each influence factor: overall, they turned out to have high levels of importance. Policy directions with high importance for each field are as follows: strengthening overseas' human network, training/educating experts for overseas projects, and accumulating experiences through Official Development Assistance projects in the fields of engineering and construction; and cost reduction and strategical cooperation with foreign companies in the manufacturing field. However, interviewees' satisfaction levels for each policy area turned out to be low. Finally, policy measures for Korean railway export for each influence factor were suggested.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.1-9
• /
• 2016

Railroad bridges account for 25% of the entire high-speed rail network. Railway bridges are subject to gradual structural degradation or fatigue accumulation due to consistent and repeating excitation by fast moving trains. Wireless sensing technology has opened up a new avenue for bridge health monitoring owing to its low-cost, high fidelity, and multiple sensing capability. On the other hand, measuring the transient response during train passage is quite challenging that the current wireless sensor system cannot be applied due to the intrinsic time delay of the sensor network. Therefore, this paper presents a framework for monitoring such transient responses with wireless sensing systems using 1) real-time excessive vibration monitoring through ultra-low-power MEMS accelerometers, and 2) post-event time synchronization scheme. The ultra-low power accelerometer continuously monitors the vibration and trigger network when excessive vibrations are detected. The entire network of wireless smart sensors starts sensing through triggering and the post-event time synchronization is conducted to compensate for the time error on the measured responses. The results of this study highlight the potential of detecting the impact load and triggering the entire network, as well as the effectiveness of the post-event time synchronized scheme for compensating for the time error. A numerical and experimental study was carried out to validate the proposed sensing hardware and time synchronization method.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.6
• /
• pp.751-760
• /
• 2021

Most bridges in Korea are over 20 years old, and many problems linked to their deterioration are being reported. The current practice for bridge inspection mainly depends on expert evaluation, which can be subjective. Recent studies have introduced data-driven methods using building information modeling, which can be more efficient and objective, but these methods require manual procedures that consume time and money. To overcome this, this study developed an image-based automaticbridge component classification network to reduce the time and cost required for converting the visual information of bridges to a digital model. The proposed method comprises two convolutional neural networks. The first network estimates the type of the bridge based on the superstructure, and the second network classifies the bridge components. In avalidation test, the proposed system automatically classified the components of 461 bridge images with 96.6 % of accuracy. The proposed approach is expected to contribute toward current bridge maintenance practice.

• Journal of the Economic Geographical Society of Korea
• /
• v.19 no.3
• /
• pp.423-436
• /
• 2016

In a densely developed metropolitan area, the subway system is often constructed to address the mobility problems. Subway system was first introduced in Seoul in late 1970s, then Korean metropolitan cities began to adopt the system later. Subway systems not only resolve the mobility problems, but also interact with regional socioeconomic landscape. This study aims to find the association between the subway network and land rent within the subway catchment areas in Gwangju metropolitan city in a spaciotemporal framework. The analysis results indicated that proximity to the subway station and the size of nearest road were positively associated with the land rent. Also from a cluster analysis, it was found that the old and new Central Business Districts as well as stations at peripheral areas had distinctive land rent change characteristics. This empirical analysis indirectly proves the strong association between land rent and urban planning and also the positive relationship between land rent and transportation networks.

• Electronics and Telecommunications Trends
• /
• v.34 no.1
• /
• pp.13-22
• /
• 2019

Various hyper-intelligent and ultra-realistic data-driven services are being increasingly developed with the goal of achieving a hyper-connected intelligent society. To sustain this trend, our research focuses on the integration and optimization of data-driven applications from several aspects such as delivery, storage, execution, and sharing of data and software, beyond the limitations of the existing network infrastructure. In this paper, we present important research issues of data-centric hyper-distributed autonomous infrastructure technologies.