Seoul Metropolitan Subway Research Articles

Network time series forecasting using spectral graph wavelet transform

We propose a novel method for forecasting network time series that occur in graphs or networks. Our approach is based on a spectral graph wavelet transform (SGWT) that provides the localized behavior of graph signals around each node. The proposed method improves forecasting performance over other existing methods. In particular, the advantages of the proposed method stand out when signals observed on a graph are inhomogeneous or non-stationary. We demonstrate the strength of the proposed approach through real-world data analysis. This analysis uses two network time series datasets: the daily number of people getting on and off the Seoul Metropolitan Subway, and daily Covid-19 confirmed cases reported in South Korea. We further conduct a simulation study to evaluate the effectiveness of the proposed method.

Trip Assignment for Transport Card Based Seoul Metropolitan Subway Using Monte Carlo Method

Trip Assignment for Transport Card Based Seoul Metropolitan Subway Using Monte Carlo Method

역사 맞춤형 정책 수립을 위한 지하철 역사의 유형화 및 특성 분석에 관한 연구: 서울 지하철 사례를 중심으로

The Seoul metropolitan subway opened in 1974, and it became popular public transportation used by an average of 4.61 million passengers per day in 2021. Furthermore, by generating a vast amount of traffic data, it is showing value beyond public transportation. Developed countries utilize a combination of public transportation data and other types of data to efficiently develop public transportation operations and passenger-specific policies. On the other hand, despite various types of subway stations being added over time, the domestic study considers data of a single type (e.g., congestion, passenger, etc.). Such studies cannot effectively utilize traffic information and are challenging to utilize in various types of Seoul metropolitan subway. In this study, we aim to classify Seoul metropolitan subway from Line 1 to Line 9 by utilizing various data related to subway stations to suggest customized policies. The experiment results showed that the areas around the subway stations were categorized into three types: highly residential types, university•capital types, and transfer•commercial types. Our findings can provide appropriate policies for each type of subway station.

Effects of built environment in subway stations on pedestrian injuries

ObjectiveIn South Korea, major events that cause many subway injuries due to trains or other facilities and force majeure such as terrorism or natural catastrophes have markedly decreased. However, there are still many other types of cases involving injury inside subway stations. To reduce this damage, it is essential to identify and evaluate the factors that have the potential to lead to event occurrence. In other transportation domains, such as in the area of road traffic, crash or collision frequencies have been estimated using a safety performance function (SPF) with explanatory variables that represent risk factors. We introduce an SPF modeling approach for the injury events inside subway stations to interpret the risks to the users moving between exit and platform for boarding and alighting and put forward implications for the operation and design of stations. MethodsWe conducted SPF modeling based on a negative binomial regression analysis, using 4039 injury event datasets for eight lines and 235 stations in the Seoul Metropolitan Subway network. The number of passengers is an exposure variable, and other explanatory variables consist of spatial attributes inside stations. ResultsThe number of users of each station has a positive and nonlinear correlation with event frequency. Several spatial attributes have positive correlations with events, especially the vertical movement of passengers and the total length of escalators, and the number of wheelchair lifts and floors in each station. Results estimate that 54% more event occurrence in transfer stations than in non-transfer stations. The total length of platforms and the area of shops in each station, on the other hand, are negatively correlated with events. ConclusionsThe results provide quantitative guidance for dealing with risk factors in each corresponding phase of the design, construction, operation, and maintenance of subway stations.

Optimum Location Analysis for an Infrastructure Maintenance Depot in Urban Railway Networks

Urban railway networks have an important role in increasing the mobility of urban populations while decreasing congestion and pollution. Railway network extension that is caused by urban growth requires additional specialists and equipment for the operation, which causes an increase in maintenance cost. A comprehensive review of the literature regarding the application of facility location problem (FLP) in the railway domain found that there are few studies, and most of the current research involves the maintenance of railway vehicles only. In this paper, the purpose of this study is to determine the optimal location of infrastructure maintenance depot (IMD) for storing special vehicles and to support the inspection and maintenance tasks in a timely and efficient manner. For a challenging problem that should reflect the characteristic that traffic load and the deterioration of railway tracks are proportional, we proposed a method of applying maintenance weights to the p-hub median problem. To examine the proposed model, the test network was constructed by collecting information on the Seoul metropolitan subway. The results of case studies show that the number and location of IMDs are significantly affected by maintenance demand and expanded network.

Rationality of Passengers’ Route Choice Considering Smart Card Tag Constraints : Focused on Seoul Metropolitan Subway Network

Rationality of Passengers’ Route Choice Considering Smart Card Tag Constraints : Focused on Seoul Metropolitan Subway Network

Cancer and non-cancer risk associated with PM10-bound metals in subways

Non-cancer and cancer health risks to humans associated with respirable particulate matter ≤10 µm (PM10) in an indoor microenvironment such as a subway cabin are currently a public concern. In this study, detailed investigations of human health risks due to PM10-bound metals in a subway cabin were conducted for the first time. Cancer risks (CRs) were estimated for inhalation exposure (CRinh) using a Monte Carlo probability density function and were compared with incremental lifetime CRs (ILCRs). Moreover, the percentage contributions of each metal to the risk levels were calculated to identify the elements potentially responsible for human health risks. The significant (>1) for non-CRs levels as HI (hazard index) was estimated for children and adults for all types of exposure (inhalation, ingestion, and dermal). Pb, Cr, and Ni were recognized as the foremost contributors to the HQ (hazard quotient) levels for all types of exposure. For subway commuters, the CRinh and ILCR levels for adults were marginally higher than the satisfactory maximum point of confinement of the lifetime carcinogenic risk level (1 × 10−5) where as CRinh for children was within the acceptable limit (1 × 10−6–1 × 10−5). Cr was identified as the predominant carcinogenic element, with 91% contribution to the total CR level in the subway cabin on the Seoul Metropolitan Subway.

Changes in Subway Ridership in Response to COVID-19 in Seoul, South Korea: Implications for Social Distancing.

IntroductionWhile numerous episodes of Coronavirus disease 2019 (COVID-19) infection and subsequent government announcements in South Korea were accompanied by widespread social distancing efforts by the people, it is unclear whether these episodes and government announcements were actually influential in improving social distancing, or whether the level of response among different demographic groups varied.MethodsData were downloaded from Seoul Data Open Plaza, and changes in the number of passengers on the Seoul Metropolitan Subway network between January 1, 2020, and March 31, 2020, were used to assess the extent to which people in Seoul practiced social distancing. Five events regarding COVID-19 that received wide public attention between January and March 2020 were identified and the changes in the number of passengers before and after each event were analyzed. Also, similar analyses were performed for 16 stations that were specific in either the age or purpose of the visit of the passengers.ResultsCompared to the third week of January 2020 (January 13-19), the mean daily number of passengers in all stations decreased by 2,984,857.4 or 40.6% by the first week of March (March 2-8). The percentage decrease in individual stations between this period was not significantly different between “young” and “old” stations (46.3% vs. 49.2%; p = 0.551) but was significantly smaller in “work” stations than in “leisure” stations (36.2% vs. 51.6%; p = 0.021). Of the five events, the first reported death due to COVID-19 in South Korea and the identification of a mass infection cluster in Daegu on February 20 were accompanied by the greatest decrease of the mean daily number of passengers (1,352,153.3 or 20.8%), while the first mass infection in Seoul on March 10 and the announcement of aggressive social distancing campaign on March 22 were accompanied by an increase in the number of passengers.ConclusionsThe number of subway passengers in Seoul decreased markedly during late February but slowly increased afterward, suggesting decreasing levels of risk perception and adherence to social distancing. Understanding the differing patterns of subway use by age or purpose of the visit may guide policymakers and the general public in shaping their future response to the current pandemic.

지리정보시스템을 이용한 수도권 전철 역세권과 안경원 분포의 연관성 분석

지리정보시스템을 이용한 수도권 전철 역세권과 안경원 분포의 연관성 분석

서울시 지하철 터널 내 입자상물질의 농도 특성 및 오염형태 분류

서울시 지하철 터널 내 입자상물질의 농도 특성 및 오염형태 분류

도시철도 차량 하부의 풍속 및 미세먼지 농도 특징

도시철도 차량의 운행은 터널 공기를 오염시키는 주된 원인이므로, 마모입자를 제거하는데 집진장치가 유용한 수단이 될 수 있다. 차량의 하부에 장착될 수 있는 집진장치의 설계조건을 파악하기 위하여 3차원 초음파 풍속계와 입자측정기를 사용하여 차량 하부의 풍속과 입자농도를 조사하였다. 2015년 2월 10일 수도권 지하철 5호선에서 운행되는 차량을 대상으로 측정하였다. 측정자료는 역 사이 노선의 형상(직선, 곡선)과 차량 속도패턴(가속, 정속 및 감속)을 구분하여 분석하였다. 차량속도도 함께 분석하였다. 직선 및 곡선 구간 모두 차량 하부의 평균 풍속은 차량속도의 약 30%이었고, 미세먼지(<TEX>$PM_{10}$</TEX>) 농도는 약 <TEX>$200{\mu}g/m^3$</TEX>이었다. 감속구간에서 평균 <TEX>$PM_{10}$</TEX> 농도는 가속구간에 비해 더 높았다. Since operation of railway trains is a major source of particle pollution in tunnel air, a particle removal device can be an effective measure to remove wear particles. To obtain design conditions of the particle removal device that will be installed underneath the railway trains, the wind speed and particle concentration underneath the trains were investigated using a three-dimensional ultrasonic anemometer and a DustTrak aerosol monitor, respectively. The measurements were made for the trains running on Seoul Metropolitan Subway Line 5 on February 10, 2015. The data were analyzed according to the track geometry (straight, curved) and train speed pattern (acceleration, cruising, and deceleration) between stations. Train speed was also analyzed. The average wind speed and <TEX>$PM_{10}$</TEX> concentration underneath the trains were ~30% of the train speed and <TEX>${\sim}200{\mu}g/m^3$</TEX> for both straight and curved sections. Average <TEX>$PM_{10}$</TEX> concentration for deceleration sections was higher than that for acceleration sections.

Perceived Easiness of Design of Seoul Metropolitan Subway Map

Perceived Easiness of Design of Seoul Metropolitan Subway Map

The Size-Oriented Particulate Mass Ratios and Their Characteristics on the Seoul Metropolitan Subway Lines

The purpose of the study was to initially investigate the concentration patterns of PM 1 , PM 2.5 and PM 10 in the Seoul subway lines, and then to figure out the PM behaviors of internal and external sources inside subway tunnels. The PMs were monitored by a light scattering real-time monitor during winter (Jan. 8-26 in 2015) and summer (July 2-Aug. 7 in 2015) in tunnel air, in passenger cabin air, and in the ambient air. The daily average PM 10 , PM 2.5 , and PM 1 concentrations on these object lines were 101.3±38.4, 81.5±30.2, and 59.7±19.9 μg/m 3 , respectively. On an average, the PM concentration was about 1.2 times higher in winter than in summer and about 1.5 times higher in underground tunnel sections than in ground sections. In this study, we also calculated extensively the average PM mass ratios for PM 2.5 /PM 10 , PM 1 /PM 10 , and PM 1 /PM 2.5 ; for example, the range of PM 2.5 /PM 10 ratio in tunnel air was 0.82-0.86 in underground tunnel air, while that was 0.48-0.68 in outdoor ground air. The ratio was much higher in tunnel air than in outdoor air and was always higher in summer than in winter in case of outdoor air. It seemed from the results that the in/out air quality as well as a proper amount of subway ventilation must be significant influence factors in terms of fine PM management and control for the tunnel air quality improvement.

수도권 지하철 길 찾기 정보 디자인 연구 -연계버스안내를 중심으로-

수도권 지하철 길 찾기 정보 디자인 연구 -연계버스안내를 중심으로-

IoT를 접목한 지하철 객차 내 혼잡도 평준화 시스템 설계

Abstract The Seoul Metropolitan Subway, which started operating in 1974, plays a major role in transporting 7,289thousands passengers daily. This trend of a steadily increase in passengers from 2012 has increased the congestionrate because of the limited capacity and time. To solve this problem, Seoul city is consistently working on improvingthe subway facilities, such as the construction of a detour path. This project, however, has only a slight effect onimproving the congestion rate and is too expensive to construct the facilities. Hence, this study suggests The Congestion Standardization System based on the IoT for improving the subway congestion rate. Based on the system,the expected effect analysis was performed, which resulted in a decrease in ride passengers from 34 to 20. In addition,this expected effect analysis shows that the number of subway vehicles can increase from 20 to 24. The suggestedsystem will have a significant effect on the efficiency of the management system. Keywords :

대중교통카드 자료를 활용한 도시철도 승강장 혼잡도 추정 알고리즘 개발

In some sections of the Seoul Metropolitan Subway, severe congestion can be observed during rush hours and on specific days. The subway operators have been conducting regular surveys to measure the level of congestion on trains: the results are then used to make plans for congestion reduction. However, the survey has so far focused just on train` congestion and has been unable to determine non-recurring congestion due to special events. This study develops an algorithm to estimate the platform congestion rate by time using individual public transportation card data. The algorithm is evaluated by comparison of the estimated congestion rate and the ground truth data that are actually observed at non-transfer subway stations on Seoul subway line 2. The error rates are within and the performance of the algorithm is fairly good. However, varying walking times from gates to platforms, which are applied to both non-peak periods and peak time periods, are needed to improve the algorithm.

A multivariate study for characterizing particulate matter (PM10, PM2.5, and PM1) in Seoul metropolitan subway stations, Korea

Given that around eight million commuters use the Seoul Metropolitan Subway (SMS) each day, the indoor air quality (IAQ) of its stations has attracted much public attention. We have monitored the concentration of particulate matters (PMx) (i.e., PM10, PM2.5, and PM1) in six major transfer stations per minute for three weeks during the summer, autumn, and winter in 2014 and 2015. The data were analyzed to investigate the relationship between PMx concentration and multivariate environmental factors using statistical methods. The average PM concentration observed was approximately two or three times higher than outdoor PM10 concentration, showing similar temporal patterns at concourses and platforms. This implies that outdoor PM10 is the most significant factor in controlling indoor PM concentration. In addition, the station depth and number of trains passing through stations were found to be additional influences on PMx. Principal component analysis (PCA) and self-organizing map (SOM) were employed, through which we found that the number of trains influences PM concentration in the vicinity of platforms only, and PMx hotspots were determined. This study identifies the external and internal factors affecting PMx characteristics in six SMS stations, which can assist in the development of effective IAQ management plans to improve public health.

Method of Removing Fe Particulate Matters from Subway Environments

In subway environments, particulate matter is generated continuously by abrasion between wheels, rails and brake pads, and through contact between electric carlines and the pantograph. Particulate matter, 61-79% of which is composed of iron (Fe), is dispersed throughout subway stations, including platforms and waiting rooms, by train drafts. This study proposes a method for removal of Fe particulates from subway tunnels, which involves mounting magnetic dust collectors underneath operating subway trains. A mathematical model is developed to determine the size of dust collector needed and the minimum period required to remove all Fe particulate matter accumulated in subway tunnels. When the model was applied to Seoul Metropolitan Subway Line 7, which has an operational duration of 20 years, it was estimated that up to 3 years would be required to remove accumulated particulate matter if two collectors were mounted on all subway trains. After removal of accumulated particulate matter, the overall concentration of particulate matter in the tunnel was shown to decrease by 61.6% when dust collectors were mounted on 50% of subway trains.

A Study on the Factors Affecting Crowding Degree in the Subway Train Considering the Seoul Metropolitan Subway Network and the Land Use of Its Catchment Area

A Study on the Factors Affecting Crowding Degree in the Subway Train Considering the Seoul Metropolitan Subway Network and the Land Use of Its Catchment Area

Urban structural hierarchy and the relationship between the ridership of the Seoul Metropolitan Subway and the land-use pattern of the station areas

The purpose of this research is to analyze the relationship between the ridership of the Seoul Metropolitan Subway (SMS) and the land-use pattern of its station areas to verify the assumption that the ridership of transit stations at both ends of the range of urban structural hierarchy is more affected by density than by land use diversity, whereas the ridership of the stations in between are influenced more by land use diversity than by density. The station areas were classified and clustered according to an accessibility index, which refers to the position of the urban structural hierarchy of Seoul. A multiple regression model was applied to each cluster of the station areas. Finally, the estimated models for all station areas and for the clusters were compared to verify the assumption. The results show that the subway ridership at Seoul’s CBD and fringe areas is primarily influenced by density, whereas the sub-central area is generally affected by diversity. The intermodal connectivity by bus had an influence. The results provide policy implications for Transit-Oriented Development (TOD) strategies to increase subway ridership in metropolitan areas where a number of sub-centers exist.