A monocular ranging method for forward vehicles in intelligent driving is proposed. This method measures vehicle distance more accurately under the condition of a single camera and can estimate camera attitude in real-time. For the estimation of camera pitch and yaw angles, it is achieved using road vanishing points. The images collected by the camera are sequentially processed through the Roberts operator amplitude calculation, feature point extraction, feature line segment generation, road vanishing point voting, and estimation of camera attitude to obtain pitch and yaw angles. A distance estimation network was designed, which is divided into multiple levels based on image size and incorporates image feature, integrating vehicle grounding point, and vehicle width information, effectively improving ranging accuracy. Finally, validation was conducted on KITTI data, with a relative error (AbsRel) of 8.3%. Additionally, the TuSimple dataset and continuous driving scenarios were also validated, resulting in improved performance compared to previous algorithms.
To solve the problems of narrow driving condition range, partial evaluation method and insufficient road adaptive control of trajectory tracking, the trajectory tracking accuracy and driving safety under full speed and full road adhesion coefficient were investigated. In the road adaptive model predictive control（MPC）, the discrete linear time-varying predictive model was obtained by the three-degree-of-freedom nonlinear dynamic model of the vehicle. The road adaptive speed range matching was realized according to the road adhesion coefficient detected by sensors, and the constraint condition of the speed increment was formulated. The maximum and standard deviation of path tracking error, lateral acceleration, centroid sideslip angle and front wheel sideslip angle with the change of velocity and road adhesion coefficient were obtained by integrating CarSim and Matlab softwares. Combined with the mechanism of tire sideslip, the driving safety was evaluated, and the trajectory tracking stability/instability area of vehicle under all working conditions was divided. The results show that the vehicle speed can be adaptively adjusted according to the road information to achieve excellent trajectory tracking accuracy and driving safety under all working conditions.
作为社区成长方式之一的社区微更新,在实践中取得项目制治理形态时,或隐或显地呈现出合作生产的样态.这是一种新治理取向,虽颇有成效,但亦问题频仍.从需要多元主体参与交互及利益交汇的治理理论内涵设定看,散布于城市社区的微更新,以项目制方式实施在一定程度上整合了政府、市场和社会的多重逻辑,但镶嵌其中的权力、资本与权利之间的持续张力难以在短期内得以有效消弭.从"社区微更新何以有效达成"的务实理解出发,持续强化社区合作治理,需要激发社区各类主体合作治理的自主性,寻求"最大公约数",即以对社区微更新项目制的新认知、新规则、新参与、新借鉴与新监管为基本路径,引导对项目制治理逻辑的新调谐.
经济政策不确定性对长三角城市群出口技术复杂度影响的实证研究表明:经济政策不确定性增加会通过外商直接投资和技术创新影响长三角城市群出口技术复杂度,且两者关系表现出"边际效应"递增的非线性特征.从区域差异来看,经济政策不确定性对长三角中心区城市的出口技术复杂度影响更为显著;从政策差异来看,财政政策、贸易政策的不确定性对长三角城市群出口技术复杂度提升具有正向促进作用,货币政策和汇率政策的不确定性则产生了负向影响.政府应关注经济政策不确定性的区域效应,充分发挥中心区城市的带动作用,加强产业集聚和升级,提高各城市出口产品技术含量,促进长三角城市群的外贸高质量发展.
基于2000-2021年中国A股上市公司面板数据构建的双向固定效应模型,实证检验了知识产权保护对企业全要素生产率的影响效应及作用机制.研究结果表明:知识产权保护对企业全要素生产率具有显著的促进作用,且该结论在经历一系列稳健性检验和内生性检验后仍然成立.影响机制分析结果表明,自主创新和外来技术溢出是知识产权保护助推企业全要素生产率增长的重要中介路径.异质性分析结果显示,知识产权保护对不同产业、不同规模、不同所有制企业的全要素生产率的影响效应具有显著的异质性.研究结论揭示了知识产权保护对企业全要素生产率的提升效应与影响路径,为完善知识产权战略、推动企业高质量发展提供决策参考.
