• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.413-422
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• 2017

In this study we investigate the importance of the subway station using network centrality measures. For centrality measures, we have used betweenness centrality, closeness centrality, and degree centrality. A new measure called weighted betweenness centrality is proposed, that combines both traditional betweenness centrality and passenger flow between stations. Through correlation analysis and power-law analysis of passenger flow on the Seoul metropolitan subway network, we have shown that weighted betweenness centrality is a meaningful and practical measure. We have also shown that passenger flow between any two stations follows a highly skewed power-law distribution.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.616-623
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• 2006

As we have understood the commonly launched T-DMB service from December 2005, we kindly recommend to apply LCX cable installing solution which can be covering underground subway and tunnel T-DMB signal shadow area with most efficient network implementation method. Subway passengers would be enjoyable continuous T-DMB services through LCX cable installing solution.

• Journal of KIISE
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• v.42 no.2
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• pp.272-279
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• 2015

Concurrent with the more widespread usage of smart devices, mobile users' desires are becoming much more complex. Most IT experts insist that smart devices should have additional functions to satisfy these requirements. In particular, research has concentrated on LBS (Locationbased Service), because it is considered one of the most common mobile service types. Generally, Wi-Fi has a critical limitation for use for LBS services, because it requires new network connection points whenever its location (Network Zone) changes. Unfortunately, GPS also has a systematic problem in providing LBS service in the indoor environment, because of its inaccuracy in processing data. So, to redress these limitations, iBeacon technology has been designed, and is currently used for LBS service instead of Wi-Fi or GPS. By using iBeacon, which is based on Bluetooth 4.0 LE technology, we propose a M-SAS (Mobile-Subway-Alarm-Service System) that could accurately and timely provide its users with various mLBS (micro LBS) services, such as current user location, and subway arrival time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.95-104
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• 2018

Using network betweenness centrality we attempt to analyze the characteristics of Seoul metropolitan subway lines. Betweenness centrality highlights the importance of a node as a transfer point between any pairs of nodes. This 'transfer' characteristic is obviously of paramount importance in transit systems. For betweenness centrality, both traditional betweenness centrality measure and weighted betweenness centrality measure which uses monthly passenger flow amount between two stations are used. By comparing traditional and weighted betweenness centrality measures of lines characteristics of passenger flow can be identified. We also investigated factors which affect betweenness centrality. It is the number of passenger who get on or get off that significantly affects betweenness centrality measures. Through correlation analysis of the number of passenger and betweenness centrality, it is found out that Seoul metropolitan subway system is well designed in terms of regional distribution of population. Four measures are proposed which represent the passenger flow characteristics. It is shown they do not follow Power-law distribution, which means passenger flow is relatively evenly distributed among stations. It has been shown that the passenger flow characteristics of subway networks in other foreign cities such as Beijing, Boston and San Franciso do follow power-law distribution, that is, pretty much biased passenger flow traffic characteristics. In this study we have also tried to answer why passenger traffic flow of Seoul metropolitan subway network is more homogeneous compared to that of Beijing.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.210-215
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• 2003

At present, communication network for subway is making use of the train radio system for main network and normally established a base station every three subway station. It is talk over the telephone between a locomotive and the traffic control for careful train service. Besides, mobile telephone equipment is using for service improve and convenience to passengers such as 011, 016, 017, 019 and what not. However, the train radio system has been occurring a various problems when a state of emergency because it is able to compose only one communication route each base station zone. We could have improving like this problems through induce the TRS(Trunked Radio System), though because have been able to compose multilateral communication route in case of linking with LCX(Leaked Coaxial) cable which is established. Therefore, we could be able to a fitting meet the emergency as train firing etc.. and efficient use of limited frequency resources.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2762-2767
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• 2011

With increasing use of wireless mobile devices like smartphone and tablet PC, telecommunication companies have been providing the internet service by installing a multitude of access points (AP) in subway stations. Most of these APs use frequency of 2.4 GHz band range and the three telecom providers (SKT, KT, LGT) are using the limited channels within this range without any regulations. The channels within 2.4GHz band are already saturated as the companies are setting up wireless AP even within the subway trains for better service. This can affect other 2.4GHz wireless devices used for other purposes with channel interference, etc. This study has tested and analyzed the effects of the wireless APs installed within the subway stations and trains for the internet service on ZigBee-based sensor network for the intelligent surveillance system of urban transit, which is currently being developed and installed.

• Journal of the Korean Professional Engineers Association
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• v.42 no.3
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• pp.41-46
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• 2009

A new subway, line 9 linking Western and Eastern Seoul began its services for citizens between Gimpo airport and Gangnam area within 30 minutes by express transit service. Seoul Metro Line 9 Corporation plans to operate both local transit service which will stop at every station, and express transit service that will stop at several key stations including junctions. The passengers on line 9 will be able to transfer to lines 2, 3, 5, 8, Bundang and Incheon International Airport. The Line 9 is expected to disperse the demand for line 2, having the most number of subway users, and will provide passengers with less crowded travel. The new line will also help residents in southern Seoul outskirts and Gyeonggi provincial cities including Bundang vicinity, and Gangdong area commuters get better access to Gimpo and incheon Airports. The Corporation expects to transfer 560,000 passengers daily by the subway line 9. Seoul Development Institute conducted network reshuffle study for Seoul Metro system to sort out congestion problem due to its irrational line alignments and inconvenient transfer. Among several candidate plans of network reshuffling, the direct connection of line 9 with line 5 was chosen as a pilot study. The study found that direct connection of the 2 lines is essential for enhancing transit utility and reducing automobile commuters.

• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.397-405
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• 2010

This study proposes visualization methods of the diurnal passenger flows on the Metropolitan Seoul Subway system (MSSs) and examines the passenger trip behaviors of major central business districts (CBDs). We mine the MSS passenger flow information from a single day T-card passenger trip transaction database. It is practically intractable to analyze such flows, involving huge, complex space-time data, by means of general statistical analysis. On the other hand, dynamic visualizations of the passenger flows make it possible to analyze intuitively and to grasp effectively characteristics of the passenger flows. We thus propose several methods to visualize the passenger flow information. In particular, we visualize dynamic passenger flows of each link on the subway network and analyze the time-space characteristics of passenger ridership for the three major CBDs. As the result, we can ascertain the strong association between CBD and subway line and clarify the distinction among three major CBDs in the diurnal patterns of subway passenger flow.

• Journal of Korean Society of Transportation
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• v.1 no.1
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• pp.104-120
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• 1983

Alternative generation and evaluation in the transportation planning process are generally considered the two most important areas of research. It is, however, unfortunate that most of Korean transportation network systems are evolved without thorough investigation of alternatives and that underplanned systems as well as over-planned systems ar blamed for the current transportation problems. This paper investigates the practical use of formal methodology of alternative generation and evaluation. The maximum possible alternative network approach and the computer oriented network evaluation method developed by KIST and applied for Pusan subway study are summarized to demonstrate their practical usefulness. The practical problems centering around the quantification of evaluation criteria ar also summarized for further studies.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1756-1760
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• 2008

In this study, it was suggested how to monitor the air quality with use of intelligent wireless sensor network in the subway station. When Zigbee-based ubiquitous sensor network was used, smaller budget was required in configuring the system compared to existing air-quality monitoring method and this system may easily be configured due to easy installation of communication cables. The study will be continued to supplement the network systems currently installed in subway stations and the completion of development of this system is expected to make a large contribution in improvement of indoor air quality.