In this study, the distribution characteristics of particulate matter (PM) in subway platforms were investigated, and the performance of hybrid filter systems was determined through the removal efficiency of PM according to various flow rates and filter structures. The hybrid filter systems were constructed in magnetic systems as (Magnet-Magnet (MM) filters and Magnet-Cascade (MC) filters). PM removal efficiencies of these filters were investigated at a subway platform for three days including weekdays and weekends. The compositions of collected PM were also analyzed. Based on the PM measurement in the subway platforms, it was confirmed that the operation of trains had a significant effect on the increase of PM concentration, and a large number of PMs were less than 1 μm in size. For the MC filter, the removal efficiency of PM1 based on the number of particles was up to 30.5%, demonstrating a relatively high removal efficiency in comparison with the MM filter. In terms of PM10, PM removal efficiencies of the MC filter with respect to the mass concentration and the number of particles were 48.3% and 14.5%, respectively. For the MC filter, it was found that the PM removal efficiency was enhanced with the increase in the flow rate. Moreover, the relatively large particle size PM (i.e., 7.5 μm - 10 μm) denoted a maximum removal efficiency of 97% in terms of the number of particles. All PMs collected by the filter were Fecontaining PMs. As a field experiment using the hybrid filter, the applicability of magnetic particle control technology was approved. Based on this result, it is expected that this study will be used as background research for the development of fine dust control technologies in a subway environment.

Although airborne wear particles (AWPs) generated from wheel-rail contacts are the major source of particulate matter (PM) in subway systems, studies on reducing the generation of such particles in order to enhance air quality are extremely rare. Therefore, this study investigated the effect of applying water-lubricant (applying tap water) on improving air quality by reducing the mass concentration (MC) of AWPs from wheel-rail contacts at a train velocity of 73 km/h using a twin-disk rig. An optical particle sizer was used to measure the MC of particles with the diameter range of 0.3 μm~10 μm. The results showed that the generation trends regarding PM1, PM2.5, and PM10 were different for dry and water-lubricated conditions: all three PMs showed an increasing-decreasing trend with slip rate under dry conditions; however, they were almost constant with slip rate under water-lubricated conditions. The particle size distributions were also different for dry and water-lubricated conditions: the peak occurred in multi-modal with the largest peak at approximately 6 μm in diameter under dry conditions; whereas, the peak occurred in bi-modal with the largest peak at approximately 0.9 μm in diameter under water-lubricated conditions. In addition, MCs were mostly smaller under water-lubricated conditions than dry conditions except at approximately 0.9 μm in diameter. Applying water significantly decreased PM1~2.5 and PM2.5~10 by more than 95%. This caused a decrease in PM2.5 and PM10 by 48.1% and 78.5%, respectively. On the other hand, applying water increased PM0.3~1 (i.e., PM1) by 52.8%, possibly owing to the effect of water vapor and mineral crystals from tap water. Overall, these findings indicate that water-lubrication can improve air quality in subway systems by reducing the MC of APWs generated from wheel-rail contacts. This study may provide a reference for future studies seeking to improve air quality in subway systems by reducing AWPs generated from wheel-rail contacts by applying lubricants.

This study investigated the indoor air quality conditions of public transportation according to the changing of seasons and different times of the day. We measured the concentration of PM10 and CO2, which are substances subject to control measures and limits established by Ministry of Environment for public transportation, and compared actual levels whit the legal standard. Public transportation was classified as subway lines (form 1 to 4), trains (KTX, ITX) and buses. The PM10 concentration was measured as being high during peak hours in winter compared to that in summer. On the other hand, the PM10 concentration in trains and buses was shown to be low. The CO2 concentration in public transportation was recorded as being higher than the legal standard. PM10 concentration was affected by the inflow of outdoor air, and CO2 concentration was influenced by the number of people in a particular space or environment. This survey focused on the indoor air quality of public transportation. The basic data could prove useful in formulating policies to promote and maintain good indoor air quality with regard to public transportation.

With the development of public transportation, the use of subways as a means of transportation in the city center is increasing, so that vibrations and structural noises are emerging as a new environmental issues. This study can be used as a basis for research on subway safety and shock mitigation by applying vibration-proof mat.

목적 : 본 연구는 신경발달 장애 아동들에게 작업기반(occupation-based) 중재를 그룹 프로그램으로 적용하여 작업 수행의 질, 수행도 및 만족도, 프로그램에 대한 만족도의 효과를 알아보고자 하였다. 연구방법 : 신경발달 장애 아동 10명을 대상으로, ADOC-S(Aid for Decision making in Occupation Choice-School) 및 COPM(Canadian Occupational Performance Measure)을 사용하여, 모든 클라이언트에게 의미 있고 공통된 작업 목표를 수립 하였다. ‘지하철 이용’ 작업수행 분석한 후에 PQRS(Performance Quality Rating Scale)를 사용하여 작업수행의 질 변화를 조사하였다. 작업기반 중재는 가장 자연스럽고 실제생활과 비슷한 상황에서 의미 있는 작업을 직접 수행하며 진행되었다. 실험은 사전평가 1회기, 중재기는 주 1회, 회기당 100분, 8주간, 총 8회기 진행되었고 사후 평가 1회기 실시되었다. 결과 : 작업수행의 질인 PQRS에서는 중재 전에 비해 중재 후 38.10의 증가를 보였다. 유지, 보상 및 적응 접근을 적용하여 초기 회기(1~4회기)에 큰 증가율이 나타났다. COPM의 수행도는 중재 전에 비해 5.80, 만족도는 7.00의 증가가 나타났다. 또한 보호자 인터뷰를 통한 프로그램 만족도에서 높은 점수가 나타났다. 결론 : 작업기반 중재는 신경발달장애 아동의 작업수행을 향상시킬 수 있는 중재방법이며, 수행도 및 만족도, 프로그램 만족도에 긍정적인 결과를 도출할 수 있었다.

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.

The purpose of this study is to develop correction formulas using the results of measurement by PMS 103, which is a weight method measuring device, and by Dusttrak (TSI, USA), DustMate (Turnkey Instrument Ltd., UK), and LD-5 (SIBATA, Japan), which are light scattering measuring devices. The objective is to evaluate and identify new standards (to develop a proposal) in order to complement the limitations of the existing measurement methods of public transportation vehicle indoor air quality by utilizing the three nephelometer type measuring devices. In the case of non-rush hours, the PMS values were estimated using an estimation regression equation. Statistically, the PMS values that were actually measured were not significantly different (p-value=0.4375, 0.4375, 1.000). With respect to the agreement between the two values, ICC was 0.99 in the case of the estimation regression equation using LD-5 values, 0.97 in the case of the estimation regression equation using Dusttrak values, and 0.84 in the case of the estimation regression equation using DustMate values to allow for the identification of agreement at greater levels. In the case of rush hours, the PMS values were estimated using an estimation regression equation. Statistically, the PMS values that were actually measured were not significantly different (p-value=0.3125, 0.6250, 0.8125). With respect to the agreement between the two values, ICC was 0.92 in the case of the estimation regression equation using LD-5 values, 0.91 in the case of the estimation regression equation using Dusttrak values, and 0.89 in the case of the estimation regression equation using DustMate values to allow for the identification of agreement at greater levels.

The subway is a common transportation system accessed by over 8 million people on a daily basis in Metropolitan Seoul area. The subway ventilation system located on a street occupies a large area of walkways which cause inconvenience to the public. In this paper, approaches to reduce the ventilation sitting area on the pathway are examined. 5 different preliminary models of ventilation systems are analyzed to minimize the pathway obstacle area such that the public may have an easy access to pass by on the street. The amount of the air ventilation is predicted using the CFD software to ensure an efficient ventilation. The ventilation performance is verified by theory and numerical analysis. The result shows that one of the proposed model combined with the hybrid ventilation satisfies the regulation requirement of the air quantities. We may conclude that the proposed ventilation design provides a smooth walking environment to the public while the ventilation volume is maintained to the existing ventilation system with no modification of the current ventilation holes and structures.

A single-stage electrostatic precipitator (ESP) was evaluated in terms of its performance in removing dust in subway tunnels. A wire-to-plate type ESP was tested in a small-scale wind tunnel. The effects of wire-to-wire spacing (2040 mm) and the material connecting wire-to-wire on the performance of ESP were investigated, with varying applied voltage and airflow velocity. A narrower wire-to-wire spacing showed higher collection efficiency at the same applied voltage. Lower electrical resistivity of material connecting wire to wire was more effective. Ozone generation in subway tunnel applications was insignificant.

The following study aims to estimate the configuration ratio of the ion compounds that identifies the cause of fine dust and ways to reduce it. In this study, the physical and chemical properties of fine particles in a tunnel and the configuration form of ionic composition were interpreted to establish reasonable measurement for air quality management. Seasonal measurements were performed by collecting samples from the Mia sageori subway station. Chemical Mass Balance (CMB) model was used to estimate the configuration ratio of ions in this study. The results showed that the test performed outside showed about 56.4% of total ion, with (NH4)2SO4, NH4NO3, CaCO3 and NaCl showing concentrations of 2.138 μg/m3, 1.957 μg/m3, 1.697 μg/m3 and 1.600 μg/m3, respectively, while the results indoor had CaCO3, NH4NO3, (NH4)2SO4 and NaCl showing concentrations of 2.272 μg/m3, 2.204 μg/m3, 1.656 μg/m3 and 1.342 μg/m3, respectively, about 65.1% of total ion. During the usage of tunnel, it was found that CaCO3, NH4NO3, (NH4)2SO4 and MgCO3 showed concentrations of 3.464 μg/m3, 1.732 μg/m3, 1.698 μg/m3 and 0.582 μg/m3, respectively, total ion of 70.2% was presented.

This study measured the particulate matter (PM) in a subway tunnel using a dust spectrometer and estimated the PM10 and PM2.5 using a Kriging method. For the hourly measurement, a probe was attached inside the cabin and put through the window to collect data from the outside. The Kriging method is a spatial analysis method, and time and spatial data were applied in the subway tunnel along with a PM concentration map. The result of the measurement shows that PM10 is 31.9~271.3 μg/m3 and PM2.5 is 30.9~209.5 μg/m3. In addition, The pollutant map shows that some sections have a higher concentration than other sections because of the depth and curvature of tunnel and traffic volume on the section and local construction. Also, the results show that differences concentration at different times of sampling could be distinguished. The highest concentration was found at 3 pm while the lowest was at 12 pm. We expect to use the pollutant map in planning air quality improvements for the tunnel.

This paper is focused on an economic analysis of applied air pollutant control technologies used for the particulate matters present in subway. Beneficial effects such as reduction in medical expenses and prevention of productivity loss and death are achievable through the adaptation of control technologies. The result showed that the total investment expense was 97.6 billion won and the cost-benefit was 4776.8 billion won, therefore a 4.8 benefit/ cost ratio was attained.

Seoul Metro has set up a principle of liberal translation on naming its stations that it will use thematic role in naming stations in Korean to reveal the origin of the place name and is abiding by the principle. Busan Humetro also applies the same principle. In the view that it can complement the broad principle of transliteration, the thematic role can be fully considered and used in parallel as well. Especially, when thematic role is used, the place name in Chinese characters should be considered first. Furthermore, accurate understanding on the origin of the place name should be sought. However, when looking at closely, there are mistakes in many cases, such as that, the existing Chinese character place names are not considered in thematic role, or the origin of place names are misunderstood, or Chinese characters are wrongly applied. In case of transliteration, there is no independent standard on writing Chinese characters for Korean pronunciation. Therefore, a definite implementation scheme which fully reflects ｢Template(英汉译音表)｣should be sought. Particularly, It should be considered that the common noun at the rear should be thematically translated or its original pronunciation be written as is. In common nouns at the rear which reveal the natural topography, there are many cases that the common nouns at the rear have lost the topographic informativity. Therefore, it would be appropriate to do transliteration for the whole place name in case the common noun at the rear does not contain the information of the relevant region. However, looking at the actual translation examples, the place names containing the old topographical information were thematically translated uniformly, for example, 나루(ferry)→渡口, 다리(bridge)→橋, 샛강(side river)→江, 내(stream)→川, 못(pond)→池, etc. In the cases that the station name contains the needed information, for example, 성당못(Catholic church pond)→聖堂池 in Daegu Subway, the thematic role is necessary, however, it should be noted that there is a possibility of conveying unnecessary information, like, 여의나루(Yeouinaru)→汝矣渡口. In contrast to this, for the cases of public offices or institutions, it is basically necessary to transfer into corresponding offices or institutions in China. Presently, it is written literally as 시청(city hall)→市厅 or 구청(borough office)→区厅, but a way to change this to 市政府, or 区政府 should be considered. It would also be proper to write 검찰청(Public Prosecutors’ Office) to 检察院, rather than 检察厅. In cases that the Chinese character writings are not commonly used, like 政府厅舍, It would be also appropraite to try to find words which are commonly used, like 政府办公大楼, rather than writing as 厅舍. However, for the institutions like 国会议事堂, which does not exist in China, should be treated as exceptions. It would be awkward to translate it into 人民大会堂 overly. Because their roles are completely different each other. On the other hand, in case of writing an English word place name into Chinese, it is necessary to judge whether it is a common noun or a proper noun. If it is a common noun, thematic role would be appropriate, and if it is a proper noun, transliteration should be done. The most problematic cases are when Chinese characters are written together while the English word place names are not translated; Centum City and Renecite Station fall under this category. For Centum City, translated words such as 仙登城 or 仙腾城, which have transliteration and thematic role together, could be suggested, and for Renecite, transliterations such as 日内西德 or 日内西特 could be suggested. In translating Chinese words, it is particularly important to have uniformity whether it is by transliteration or by thematic role. For the case of 버스터미널(bus terminal), it would be embarrasing to write differently, like, 巴士客运站, 高速客运站, 客运站, etc. It is necessary to unify into one expression of, for example, 汽车客运站, or something else. Sometimes 삼거리(three way intersection) is written differently as 三岔路口 and 丁字路口, and this should also be unified. Besides, there are cases where the possibility of transliteration was suggested, like, 골(valley)→谷尔, 고개(pass)→谷给, 바위(rock)→巴伊, or 내(inside)→內. In these cases where the common nouns at the rear appear frequently, it seems necessary to form a consensus to unify the transliteration.