• Title/Summary/Keyword: heavy traffic

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A study of PM-10 and Heavy Metal characteristics in the air at the each site of a subway station. (지하철역사내 측정위치별 PM-10 및 중금속 농도특성에 관한 연구)

  • Chang Jung-Wook;Cho Jang-Je;Choi Woo-Gun;Park Duk-Sin;Jung Woo-Sung;Kim Tae-Oh
    • Proceedings of the KSR Conference
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    • 2003.10c
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    • pp.389-394
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    • 2003
  • Subway has been used one of major public transportations because of overpopulation and heavy traffic problems in the metropolitan areas. So, the air pollution has been serious. In this study, continuous date of PM-10 (particles with aerodynamic diameter < $10{\mu}m$) and heavy metal concentration measurements for winter, spring and summer. These measurements have been carried out in the outdoor, concourse, platform, tunnel. The study results showed that the average seasonally concentration of PM-10 particles were $141.57{\mu}g/m^3$ in winter. $129.34{\mu}g/m^3$ in spring and $122.73{\mu}g/m^3$. The average concentration of PM-l0 particles at indoor higher than outdoor. The concentration of Fe, Cu, showed the largest peak concentrations during the respective season.

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A Study on the Indoor Air Quality in Subway - PM-10 and Heavy Metals - (지하철역에서의 공기질 평가에 관한 연구 - PM-10 및 중금속 -)

  • 배상호;최우건;박덕신;정우성;김태오
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.555-560
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    • 2002
  • Subway has been used one of major public transportations because of overpopulation and heavy traffic problems in the metropolitan areas. In this study, continuous date of PM-10(particles with aerodynamic diameter < 10$\mu\textrm{m}$) and heavy metal concentration measurements for autumn and winter period were analysed. These measurements have been carried out at the outdoor, concourse, platform, tunnel. The study results showed that the average seasonal concentration of PM-10 particles were 181.01$\mu\textrm{g}$/㎥ in autumn and 129.03$\mu\textrm{g}$/㎥ in winter, respectively. The concentration of Fe, Cu showed the largest peak concentrations during the respective season.

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A Study on the Impacts of Truck Platooning on Freeway Traffic-Flow and the Effect of Dedicated Lane (고속도로 화물차의 군집주행이 교통류에 미치는 영향 및 전용차로 효과 연구)

  • KIM, Joohye;Lee, YoungIhn
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.19 no.5
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    • pp.52-69
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    • 2020
  • Considering the need for an infrastructure-level review, this study analyzed the impact of truck platooning on freeway traffic flow and the effect of dedicated lanes based on domestic road and traffic conditions. According to the study, the higher traffic volume and truck ratio, the higher ratio of platoons and the greater size of platoons are formed, which results in greater effect of increasing the average speed of the network. Therefore, the routes with heavy traffic and heavy cargo traffic could be positively considered for truck platooning. However, the analysis showed that the effect of increasing the average speed of the entire network is difficult to expect in the event of a queue due to entry and exit, and that the overall network's throughput could be reduced. Therefore, traffic operation strategies associated with the access road, such as securing capacity of the connection, are needed to maximize the effect of truck platooning. When it comes to the effect of dedicated lane, it could have a positive effect only if one lane was fully operated by automated trucks under the condition of 100% MPR, which allowed positive effects in all aspects, such as higher average speed, throughput, and reduced conflict rates.

Simple AC/CRC Composite Pavement Design Using MEPDG (MEPDG를 이용한 아스팔트/연속철근 콘크리트 복합포장 간편 설계)

  • Baek, Jongeun;Kim, Hyung Bae;Lee, Hyun Jong
    • International Journal of Highway Engineering
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    • v.16 no.6
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    • pp.1-8
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    • 2014
  • PURPOSES : Analysis and design of asphalt concrete (AC) and continuously reinforced concrete (CRC) composite pavements. METHODS : In this study, the service life of the AC/CRC composite pavements was determined based on the probabilistic method in the mechanistic-empirical pavement design guide(MEPDG). Typical pavement design was provided with respect to heavy truck traffic volume of highways. RESULTS : The service life of the composite pavements based on IRI was shorter than that based on rutting at lower traffic volume, but this trend was switched at higher traffic volume. CONCLUSIONS : It is concluded that the main distress affecting the service life of the composite pavements was longitudinal roughness and rutting. Roughness became lower, but rut depth became greater as the stiffness of the CRC increased.

A New Architecture to Offload Network Traffic using OpenFlow in LTE

  • Venmani, Daniel Philip;Gourhant, Yvon;Zeghlache, Djamal
    • Journal of Korea Society of Industrial Information Systems
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    • v.17 no.1
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    • pp.31-38
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    • 2012
  • Next generation cellular applications and smart phone usage generate very heavy wireless data traffic. It becomes ineluctable for mobile network operators to have multiple core network entities such as Serving Gateway and Packet Data Network Gateway in 4G-LTE to share this high traffic generated. A typical configuration consists of multiple serving gateways behind a load-balancer which would determine which serving gateway would service a end-users'request. Such hardware is expensive, has a rigid policy set, and is a single point of failure. Another perspective of today's increasingly high data traffic is that besides it is being widely accepted that the high bandwidth L TE provides is creating bottlenecks for service providers by the increasing user bandwidth demands without creating any corresponding revenue improvements, a hidden problem that is also passively advancing on the newly emerging 4G-LTE that may need more immediate attention is the network signaling traffic, also known as the control-plane traffic that is generated by the applications developed for smartphones and tablets. With this as starting point, in this paper, we propose a solution, by a new approach considering OpenFlow switch connected to a controller, which gains flexibility in policy, costs less, and has the potential to be more robust to failure with future generations of switches. This also solves the problem of scaling the control-plane traffic that is imperative to preserve revenue and ensure customer satisfaction. Thus, with the proposed architecture with OpenFlow, mobile network operators could manipulate the traffic generated by the control-plane signaling separated from the data-plane, besides also reducing the cost in installing multiple core-network entities.

Extrapolation of extreme traffic load effects on bridges based on long-term SHM data

  • Xia, Y.X.;Ni, Y.Q.
    • Smart Structures and Systems
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    • v.17 no.6
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    • pp.995-1015
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    • 2016
  • In the design and condition assessment of bridges, it is usually necessary to take into consideration the extreme conditions which are not expected to occur within a short time period and thus require an extrapolation from observations of limited duration. Long-term structural health monitoring (SHM) provides a rich database to evaluate the extreme conditions. This paper focuses on the extrapolation of extreme traffic load effects on bridges using long-term monitoring data of structural strain. The suspension Tsing Ma Bridge (TMB), which carries both highway and railway traffic and is instrumented with a long-term SHM system, is taken as a testbed for the present study. Two popular extreme value extrapolation methods: the block maxima approach and the peaks-over-threshold approach, are employed to extrapolate the extreme stresses induced by highway traffic and railway traffic, respectively. Characteristic values of the extreme stresses with a return period of 120 years (the design life of the bridge) obtained by the two methods are compared. It is found that the extrapolated extreme stresses are robust to the extrapolation technique. It may owe to the richness and good quality of the long-term strain data acquired. These characteristic extremes are also compared with the design values and found to be much smaller than the design values, indicating conservative design values of traffic loading and a safe traffic-loading condition of the bridge. The results of this study can be used as a reference for the design and condition assessment of similar bridges carrying heavy traffic, analogous to the TMB.