30 research outputs found

    Analysis of Red-Light Violation Behavior of Pedestrian Two-Stage Crossing at a Signalized Intersection

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    Studying pedestrians’ twice-crossing behavior is of great significance to enhance safety and efficiency for pedestrians at signalized intersections. However, researchers have paid little attention to analyze and model pedestrians’ red-light running behavior on a two-stage crossing at signalized intersections. This paper focuses on analyzing the characteristics of pedestrian red-light violation behavior at the two stages, including the time distribution of violation behavior, the consistency of violation behavior, and the violation behavior in group.  A goal-oriented and time-driven red-light violation behavior model was proposed for pedestrian two-stage crossing. A video-recording method was used to collect field data, and the results show that pedestrians in the two directions present different red-light violation behaviors in time selection and violation count, as well as, pedestrians in the two stages of a direction present different red-light violation behaviors in time selection. The main reasons leading to the phenomena were analyzed, regarding from people’s cognitive psychology and visual perception. The results also show that the proposed model is effective in simulating pedestrian red-light violation behavior of twice crossing. This research provides a theoretical basis for optimizing signal timing, improving pedestrian safety and developing user-friendly transportation system

    Analysis of Route Choice for Pedestrian Two-Stage Crossing at a Signalized Intersection

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    Studying pedestrians’ twice-crossing behavior is of great significance to enhance safety and efficiency for pedestrians at signalized intersections. However, limited attention has been paid to analyze and model pedestrians’ behavior patterns of twice crossing. The purpose of this paper is to determine pedestrians' route choices for twice crossing at a signalized intersection, focusing on the waiting position (to cross the street) and walking route. A goal-oriented and time-driven model was proposed to analyze pedestrians’ twice-crossing behavior at signalized intersections, where the two directions have different pedestrian signal timing. A video-recording method was used to collect field data in order to obtain pedestrian preferences in choosing a walking route. It was found that pedestrians in the two directions present different preferences toward walking route, in waiting position, directional change and route type. The results showed that the proposed model is effective in simulating pedestrian route-choice behavior of twice crossing. This research provides a theoretical basis for identifying pedestrian movement intention, optimizing signal timing, and improving pedestrian infrastructure at signalized intersections.

    Flood Control and Aquifer Recharge Effects of Sponge City: A Case Study in North China

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    Sponge City is an integrated urban stormwater management approach and practice to tackle waterlogging, flooding, water scarcity, and their related problems. Despite many positive effects of Sponge City on flood control that have been investigated and revealed, the effect on aquifer recharge is still less known. Considering maximizing the function of natural elements such as surface water bodies and subsurface storage space, to minimize the use of a gray drainage system, a Sponge City design was proposed to substitute the planning development scheme in the study area. The stormwater management model of SWMM (storm water management model) and the groundwater flow model of MODFlow (Modular Three-dimensional Finite-difference Groundwater Flow Model) were adopted to evaluate the flood-control effect and aquifer-recharge effect, respectively. Compared with the traditional planning scenario, the peak runoff is approximately 92% less than that under the traditional planning scenario under the condition of a 5-year return period. Due to the increase in impervious areas of urban construction, the total aquifer recharge from precipitation and surface water bodies was decreased both in the present planning scenario and the Sponge City design scenario. However, the Sponge City design has a positive impact on maintaining groundwater level stabilization and even raises the groundwater level in some specific areas where stormwater seepage infrastructure is located

    Flood Control and Aquifer Recharge Effects of Sponge City: A Case Study in North China

    No full text
    Sponge City is an integrated urban stormwater management approach and practice to tackle waterlogging, flooding, water scarcity, and their related problems. Despite many positive effects of Sponge City on flood control that have been investigated and revealed, the effect on aquifer recharge is still less known. Considering maximizing the function of natural elements such as surface water bodies and subsurface storage space, to minimize the use of a gray drainage system, a Sponge City design was proposed to substitute the planning development scheme in the study area. The stormwater management model of SWMM (storm water management model) and the groundwater flow model of MODFlow (Modular Three-dimensional Finite-difference Groundwater Flow Model) were adopted to evaluate the flood-control effect and aquifer-recharge effect, respectively. Compared with the traditional planning scenario, the peak runoff is approximately 92% less than that under the traditional planning scenario under the condition of a 5-year return period. Due to the increase in impervious areas of urban construction, the total aquifer recharge from precipitation and surface water bodies was decreased both in the present planning scenario and the Sponge City design scenario. However, the Sponge City design has a positive impact on maintaining groundwater level stabilization and even raises the groundwater level in some specific areas where stormwater seepage infrastructure is located

    The Therapeutic Effect of the Chinese Herbal Medicine, Rehmanniae Radix Preparata, in Attention Deficit Hyperactivity Disorder via Reversal of Structural Abnormalities in the Cortex

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    Rehmanniae radix preparata is extracted from wine-steaming the Rehmannia root, a scrophulariaceae plant. It has been used for thousands of years with effects of nourishing kidney-yin, benefiting essence and filling marrow based on traditional Chinese medicine (TCM) theory. Rehmanniae radix preparata has antioxidant, antisenescence, anti-inflammatory, and neuroprotective properties. It is the most popular Traditional Chinese medicinal compound (TCMC) used in attention deficit hyperactivity disorder (ADHD) therapy. However, few studies have been conducted exploring the effects and potential mechanisms of Rehmanniae radix preparata alone on ADHD. Recent studies have shown that Rehmanniae radix preparata inhibits spontaneous activity in mice, improves learning and memory in rats following thalamic arcuate nucleus injury, and exhibits antidepressant effects. Catalpol, an active component of Rehmanniae radix preparata, elevates brain-derived neurotrophic factor (BDNF), and attenuates neuronal apoptosis and energy metabolism failure. ADHD is characterized by hyperactivity-impulsivity and impairments in learning and memory. Its pathomechanism is closely related to structural abnormalities in the cortex that is mediated by dysfunction in neuronal development, apoptosis, and energy metabolism. We hypothesize that Rehmanniae radix preparata may be effective at treating ADHD by alleviating neurodevelopmental abnormalities, neuronal apoptosis, and energy metabolism failure

    Multi-objective optimisation of bio-inspired lightweight sandwich structures based on selective laser melting

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    Multi-objective optimisation of the bio-inspired lightweight structure is developed by response surface methodology (RSM) and non-dominated sorting genetic algorithm II (NSGA-II) for future applications in the aerospace and military fields. Multilayer bio-inspired sandwich structures of Ti6Al4V alloy are designed and fabricated by selective laser melting (SLM). Results show that the bio-inspired sandwich structures can be optimized by RSM and NSGA-II with a relative error rate of experiment and response value less than 10%. The bio-inspired sandwich structures with different core-arranged configurations were destroyed layer by layer under out-of-plane loadings with a primary failure mode of the core breaking. Increasing the layer number of cores can improve the comprehensive mechanical performances of multilayer bio-inspired sandwich structures with cross-arranged configurations but will decrease the energy absorption capacity of those with parallel-arranged configurations. Furthermore, the two-layered bio-inspired sandwich structure under cross-arranged configurations has the most excellent comprehensive performances with the specific energy absorption of 9.16 × 103 J/kg and the energy absorption of 154.80 J, respectively
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