通讯机构:
[Jianrong Cai] S;School of Civil Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
摘要:
Reversible lanes constitute an important solutions for sustainable transportation, with the aim to solve the practical problem of reversible lane optimization of urban road networks constrained by adjustment time. Considering the relationship between the number of lanes and the capacity of sections, a mixed-integer bilevel programming model of reversible lane optimization constrained by adjustment time is constructed in order to minimize the total travel time of the system. The results show that the model can effectively obtain the optimal strategy for any number of reversible sections subject to adjustment time constraints. With the increase of the number of reversible sections that can be optimized within the adjustment time, the cumulative reduced system time increases monotonically and the road network optimization effect improves, but as a whole, the optimization effect of the newly added reversible sections in each stage shows a decreasing trend. When the number of reversible sections that can be optimized within the adjustment time reaches a certain number, increasing the number of reversible sections will have a limited further effect on the overall system. For the reversible lane optimization problem of urban road networks, only efficient reversible sections need to be optimized to achieve a good optimization effect.
通讯机构:
[Jianbo Yuan] S;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要:
Based on analytical and simulation methods, this paper discusses the path choice behavior of mixed traffic flow with autonomous vehicles, advanced traveler information systems (ATIS) vehicles and ordinary vehicles, aiming to promote the development of autonomous vehicles. Firstly, a bi-level programming model of mixed traffic flow assignments constrained by link capacity is established to minimize travel time. Subsequently, the algorithm based on the incremental allocation method and method of successive averages is proposed to solve the model. Through a numerical example, the road network capacity under different modes is obtained, the impact of market penetration on travel time is analyzed, and the state and characteristics of single equilibrium flow and mixed equilibrium flow are explored. Analysis results show that the road network can be maximized based on saving travel time when all vehicles are autonomous, especially when the autonomous lane is adopted. The travel time can be shortened by increasing the market penetration of autonomous vehicles and ATIS vehicles, while the former is more effective. However, the popularization of autonomous vehicles cannot be realized in the short term; the market penetration of autonomous vehicles and ATIS vehicles can be set to 0.2 and 0.6, respectively, during the introduction period.
作者机构:
[Zhang, Yinghui; Zhang, Jinfan; Wang, Da; Chen, Yun] Changsha Univ Sci & Technol, Dept Transportat Engn, Changsha 410114, Peoples R China.;[Zhang, Jinfan] Hunan City Univ, Dept Civil Engn, Yiyang 413000, Peoples R China.
通讯机构:
[Jinfan Zhang] D;Department of Civil Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Department of Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
关键词:
construction megaproject team;multiteam system;team learning
摘要:
The construction megaproject team (CMPT) emphasises integration as a megaproject multiteam system (MTS) to facilitate knowledge learning. This paper synthesises the CMPT structure characteristics and team learning processes into a conceptual framework named the CMPT-MTS learning framework to advance future CMPT learning research. The constructs included are identified from published research. A case example is the island and tunnel project of the Hong Kong–Zhuhai–Macao Bridge, which provides practical grounding for framework refinement. The conceptual framework deemed to follow a cyclical pattern identifies the CMPT-MTS structure variables and team learning processes affecting learning outcomes and contextual variables hypothesised to influence the intra- and inter-team interaction. We discuss how the conceptual framework might identify the CMPT learning research gaps for future research. The framework’s contribution to the body of knowledge expands our lens to understand team learning practices in the complex CMPT by considering CMPT as an MTS.
通讯机构:
[Zi-Jian Fan] S;School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要:
In order to study the dynamic response characteristics of circular extended foundation of wind turbine in mountainous areas, a 1:10 scaled model test was carried out on the circular extended foundation of 2MW wind turbine, and the deformation characteristics of wind turbine foundation under random wind load were analyzed by ABAQUS numerical calculation. The results show that: (1) The wind turbine foundation has different stress types on the windward side and the leeward side. The components of the windward side foundation are subjected to tensile stress, while the components of the wind turbine leeward side foundation are subjected to compressive stress. (2) The strain of the foundation bolt, the strain of the foundation ring, and the strain of the foundation plate are within the allowable range of material deformation, but the relative deformation of the windward side and the leeward side is quite different. (3) The numerical calculation results of wind turbine foundation under strong wind load are compared with the failure results of scale model experiment, which shows that the overall overturning failure of foundation is a dynamic response mode of wind turbine foundation. In the design and construction, it is necessary to strengthen the research on the windward side and the leeward side and strengthen the anti-overturning design of the wind turbine expansion foundation.
摘要:
As an emerging urban public transport mode, responsive feeder transit system is flexible and can offer door-to-door services between new districts at margins with low urban transit coverage and trunk bus station. In this study, a joint optimization of running route and scheduling for responsive feeder transit under mixed demand (i.e., reservation and real-time demands) of the time-dependent road network was investigated. A two-stage optimization method was designed together with considering the mixed demands. At the first stage, the initial running route and scheduling were determined according to all reservation demands. At the second stage, the running route and scheduling were continuously optimized based on the real-time demands. The real-time demand responsive strategy, which is built up by using quantitative batch treatment rather than immediate treatment and dynamic route updating strategy for global optimization, were designed by utilizing the submission order of real-time demands. A joint optimization model of running route and scheduling was constructed based on the quantitative batch decision points in the time-dependent road network together with combination of the actual road network. In this model, the minimum total system cost was used, which is composed of the vehicle running costs and passengers' traveling time costs with constraints including vehicle capacity, passengers' time window, and vehicle running time. A solving algorithm based on the adaptive genetic algorithm was designed by considering the characteristics of the joint optimization model.
作者机构:
[Zhou, Z. -M.; Zhang, J. -F.; Long, Q.] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
通讯机构:
[Zhang, J. -F.] H;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
关键词:
Multi-objective model;Traffic management strategy;Intersection signal controlling;Fuzzy analytic process;Q-learning algorithm
摘要:
Traffic signals are one of the main traffic management tools used to control traffic flow on the roads and should reflect traffic managers' intentions in different tasks. This paper showed a multi-objective optimization model, and its algorithm was aimed at the intricate structure of traffic control. First, the indexes of queuing lengths, delay times, and stop times were chosen as the evaluation indexes of optimization model. Second, the weight of the optimization indexes was confirmed with a fuzzy analytic process (FAP) according to the traffic managers' strategy. Finally, the multi-objective optimization model was solved with the Q-learning algorithm, and thus the signal control scheme of the intersection was produced in real-time while considering the traffic management strategy. The results of the simulation showed that the method could effectively improve traffic efficiency at the intersection, and at the same time, the intentions of the traffic managers could be fully embodied.