14-10 Innovative Park-and-Ride Management for Livable Communities

Park-and-ride (P&R) has been recognized as an effective way to tackle the challenge of the last-mile problem in public transportation, i.e., connecting transit stations to final destinations. Although the design and operations of P&R facilities have been extensively investigated, there is a pressing need for a theoretically sound methodology for planning and managing P&R facilities. It is critically important to investigate where P&R facilities should be strategically located and how often transit service should be provided such that the net social benefit can be maximized. This project proposes an integrated planning methodology for locating P&R facilities and designing transit services simultaneously to promote public transportation and reduce traffic externalities in urban areas. The optimal P&R facility and transit service design problem is formulated as a mathematical program with complementarity constraints, and a solution algorithm based on the active-set approach is used to solve the optimal design problem effectively. A numerical example is employed to demonstrate that the optimal design shifts commuters from the automobile mode to transit and P&R modes and, hence, improves the net social benefit dramatically. The study provides a heretofore missing theoretical framework for integrated planning of P&R facilities and transit services

Voxel-based Urban Vegetation Volume Analysis with LiDAR Point Cloud

The 3D volume and spatial distribution of urban vegetation are highly related to the delivery of multiple ecosystem services. However, due to the intricate vegetation structure, little research has been conducted to visualize and model the 3D spatial structure of urban vegetation. This study proposes an automated voxel-based modeling method to visualize and quantify the urban vegetation volume with LiDAR point cloud and performs a case study of the No.6 Middle School campus in Hengyang City, Hunan Province, China. The PointCNN model is used to perform semantic segmentation of the LiDAR data to extract the tree points. Then the points are voxelized into a 3D volume model with 1m×1m×1m cells. The result shows that the total vegetation volume of the area is 61,192m³, accounting for 37.28% of the total voxelized study area. The green space in front of the north teaching buildings has the largest proportion of vegetation volume, 19,366m³, accounting for 68.37% of the vegetation volume of the whole campus, due to the diverse vegetation and complex structure. The automated segmentation voxel modeling process could provide an efficient way to represent the spatial distribution of urban greenery. With an adjustable voxel size, the model could be adapted to various scales from regional to neighborhood. The model could also be used to analyze the green space structure at the human scale, as well as the interactions between green space and the surrounding environment, and to provide spatial data for the evaluation of multiple ecosystem services

Planning of Fast-Charging Stations for a Battery Electric Bus System under Energy Consumption Uncertainty

Battery-powered electric buses are gaining popularity as an energy-efficient and emission-free alternative for bus fleets. However, battery electric buses continue to struggle with concerns related to their limited driving range and time-consuming recharging processes. Fast-charging technology, which utilizes dwelling time at bus stops or terminals to recharge buses in operation employing high power, can raise battery electric buses to the same level of capability as their diesel counterparts in terms of driving range and operating time. To develop an economical and effective battery electric bus system using fastcharging technology, fast-charging stations must be strategically deployed. Moreover, due to the instability of traffic conditions and travel demands, the energy consumption uncertainty of buses should also be considered. This study addresses the planning problem of fast-charging stations that is inherent in a battery electric bus system in light of the energy consumption uncertainty of buses. A robust optimization model that represents a mixed integer linear program is developed with the objective of minimizing the total implementation cost. The model is then demonstrated using a real-world bus system. The performances of deterministic solutions and robust solutions are compared under a worst-case scenario. The results demonstrate that the proposed robust model can provide an optimal plan for a fast-charging battery electric bus system that is robust against the energy consumption uncertainty of buses. The trade-off between system cost and system robustness is also addressed

Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns

[EN] Concrete-filled steel tubes have been widely used all over the world due to their superior structural behaviour. To promote the use of ecofriendly materials and to reduce the use of concrete, this paper presents an innovative type of composite column, which can be referred as bamboo-concrete filled steel tubes. In this kind of column, concrete filled in the space between the external steel tube and the inner raw moso bamboo. Bamboo-concrete filled steel tubes inherit the merits of concrete-filled steel tubes such as high load-bearing capacity and ductility performance. Besides, global buckling behaviour of a bamboo column due to its relatively large slenderness can be significantly improved, and the bamboo column with nodes could provide confinement to the infilled concrete. This paper investigated the composite effect of bamboo-concrete filled steel tubular stub columns subjected to axial compression. In addition, concrete-filled double-skin steel tubular stub columns and hollow concrete-filled steel tubular stub columns were also tested for comparison. The main experimental parameter considered was the diameter-to-thickness ratio (D/t) of steel tube. Test results indicated that the composite columns with moso bamboo pipe as inner core elements showed better ductility than the hollow concrete-filled steel tubular stub columns. The bearing capacity and ductility visibly increased with decreasing of the D/t ratio.Gan, D.; Zhang, T.; Zhou, X.; He, Z. (2018). Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 385-391. https://doi.org/10.4995/ASCCS2018.2018.7138OCS38539

Full-range Gate-controlled Terahertz Phase Modulations with Graphene Metasurfaces

Local phase control of electromagnetic wave, the basis of a diverse set of applications such as hologram imaging, polarization and wave-front manipulation, is of fundamental importance in photonic research. However, the bulky, passive phase modulators currently available remain a hurdle for photonic integration. Here we demonstrate full-range active phase modulations in the Tera-Hertz (THz) regime, realized by gate-tuned ultra-thin reflective metasurfaces based on graphene. A one-port resonator model, backed by our full-wave simulations, reveals the underlying mechanism of our extreme phase modulations, and points to general strategies for the design of tunable photonic devices. As a particular example, we demonstrate a gate-tunable THz polarization modulator based on our graphene metasurface. Our findings pave the road towards exciting photonic applications based on active phase manipulations

Public health risks and their governance in traditional fresh food market from the perspective of vulnerability theory

With the increase of risk factors in urban governance in China, traditional fresh food market has become a vulnerable part. In order to avoid the outbreak of public health crisis caused by traditional fresh food, it is necessary to analyze and evaluate the public health risks inherent in it, so as to improve the ability of public health risk management of urban government in China. From the perspective of vulnerability theory, this paper analyzes the public health risks of traditional fresh food market, and discusses the vulnerability of traditional fresh food market in nature, society, management and technical system. On this basis, this paper puts forward some countermeasures for the potential and secondary risks of the traditional fresh food market in China under the fragile system environment

Joint Design of Access and Backhaul in Densely Deployed MmWave Small Cells

With the rapid growth of mobile data traffic, the shortage of radio spectrum resource has become increasingly prominent. Millimeter wave (mmWave) small cells can be densely deployed in macro cells to improve network capacity and spectrum utilization. Such a network architecture is referred to as mmWave heterogeneous cellular networks (HetNets). Compared with the traditional wired backhaul, The integrated access and backhaul (IAB) architecture with wireless backhaul is more flexible and cost-effective for mmWave HetNets. However, the imbalance of throughput between the access and backhaul links will constrain the total system throughput. Consequently, it is necessary to jointly design of radio access and backhaul link. In this paper, we study the joint optimization of user association and backhaul resource allocation in mmWave HetNets, where different mmWave bands are adopted by the access and backhaul links. Considering the non-convex and combinatorial characteristics of the optimization problem and the dynamic nature of the mmWave link, we propose a multi-agent deep reinforcement learning (MADRL) based scheme to maximize the long-term total link throughput of the network. The simulation results show that the scheme can not only adjust user association and backhaul resource allocation strategy according to the dynamics in the access link state, but also effectively improve the link throughput under different system configurations.Comment: 15 page

Platelet activation: a promoter for psoriasis and its comorbidity, cardiovascular disease

Psoriasis is a chronic inflammatory skin disease with a prevalence of 0.14% to 1.99%. The underlying pathology is mainly driven by the abnormal immune responses including activation of Th1, Th17, Th22 cells and secretion of cytokines. Patients with psoriasis are more likely to develop cardiovascular disease (CVD) which has been well recognized as a comorbidity of psoriasis. As mediators of hemostasis and thromboinflammation, platelets play an important part in CVD. However, less is known about their pathophysiological contribution to psoriasis and psoriasis-associated CVD. A comprehensive understanding of the role of platelet activation in psoriasis might pave the path for more accurate prediction of cardiovascular (CV) risk and provide new strategies for psoriasis management, which alleviates the increased CV burden associated with psoriasis. Here we review the available evidence about the biomarkers and mechanisms of platelet activation in psoriasis and the role of platelet activation in intriguing the common comorbidity, CVD. We further discussed the implications and efficacy of antiplatelet therapies in the treatment of psoriasis and prevention of psoriasis-associated CVD

Structure Performance of Cold-formed Steel columns reinforced by Channel Sleeve under Axial and Eccentric compression

Due to the weak torsional stiffness of cold-formed thin-walled channel members, distortional buckling behavior maybe controlled the ultimate load-capacity under certain conditions. Therefore, a new section reinforced by Channel Sleeve is proposed in order to improve the structural capacity of channel columns in this paper and is performed on the axial and eccentric compression tests. The influence of Channel Sleeve spacing on the bearing capacity and failure mode is studied, and the beneficial effect of the Channel Sleeve on the bearing capacity is verified. First, the corresponding numerical modeling of the experiments is presented in detail by describing the numerical models, types of finite elements and methods of analyses. Second, the reinforced cold-formed steel members were subjected to axial and eccentric compression analysis. Next, the magnitude, direction of eccentricity and the sleeve position are varied, in order to address their effect on the columns' capacity and structural behavior. In addition, the numerical model is used to analyze the parameters such as the slenderness ratio of the specimen, the magnitude and direction of eccentricity. The influence of these parameter changes on the structural performance of the members under the action of axial and beam-column compression members is obtained. Finally, compare the bearing capacity of the axial compression specimen with the bearing capacity calculated by the North American Code