考虑能源类型的城市出租车运营效率评价研究

以分析西安市燃气型、电动型及甲醇型3种能源类型出租车在运营中的既有期望运营投入和非期望运营投入，既有期望产出和非期望产出为基础，本文构建基于DEA-Malmquist的考虑能源类型的出租车运营效率评价模型。从西安市出租车管理处提取西安市 2020 年 9~12 月期间 14946辆出租车的GPS轨迹数据，并随机选取1000辆甲醇型出租车、1000 辆电动型出租车及 1000辆燃气型出租车作为样本进行实例分析。通过处理3000辆出租车GPS数据，得到乘客在工作日和双休日不同时段的出行需求和特征，分析3种不同能源类型出租车的运营效率差异。所得结论可为西安政府部门对不同能源类型出租车的管理运营提供决策支持。     

Real-time identification of probe vehicle trajectories in the mixed traffic corridor

This paper proposes three enhanced semi-supervised clustering algorithms, namely the Constrained-K-Means (CKM), the Seeded-K-Means (SKM), and the Semi-Supervised Fuzzy c-Means (SFCM), to identify probe vehicle trajectories in the mixed traffic corridor. The proposed algorithms are able to take advantage of the strengthens of topological relation judgment and the semi-supervised learning technique by optimizing the selection of pre-labeling samples and initial clustering centers of the original semi-supervised learning technique based on horizontal Global Positioning System data. The proposed algorithms were validated and evaluated based on the probe vehicle data collected at two mixed corridors on Shanghai’s urban expressways. Results indicate that the enhanced SFCM algorithm could achieve the best performance in terms of clustering purity and Normalized Mutual Information, followed by the CKM algorithm and the SKM algorithm. It may reach a nearly 100% clustering purity for the uncongested conditions and a clustering purity greater than 80% for the congested conditions. Meanwhile, it could improve clustering purity averagely by 21% and 14% for the congested conditions and 6.5% and 6% for the uncongested conditions, as compared with the traditional K-Means algorithm and the basic SFCM. The proposed algorithms can be applied for both on-line and off-line purposes, without the need of historical data. Clustering accuracies under different traffic conditions and possible improvements with the use of historical data are also discussed.     

CZM in California: Successes and Challenges Ahead

California has a forty-year history of successful coastal zone management. The San Francisco Bay Conservation and Development Commission, the California Coastal Commission, and the State Coastal Conservancy have protected and made accessible hundreds of miles of shoreline. While each agency has played a critical role, this article focuses on the Coastal Commission. Implementing the California Coastal Act, the Coastal Commission has partnered with local government, other agencies, nongovernmental organizations (NGOs), and the public to concentrate new development in already developed areas, and much of the rural coastal zone looks as it did in 1972. The Commission has protected and expanded public shoreline access through its regulatory actions. Using strong ecological science the Commission has protected a wide variety of sensitive habitats and wetlands. And under the authority of the Coastal Zone Management Act, the Commission has reviewed thousands of federal projects to assure that they are consistent with the Coastal Act. Challenges continue, though, including population growth, sea-level rise, and inadequate funding to update local coastal land use plans to address new issues, such as climate change adaptation. New investment is needed at the national, state, and local level to continue the success of the California program.     

人机协作系统中车辆轨迹规划与轨迹跟踪控制研究

自动驾驶系统需具备响应驾驶人意图且有效执行驾驶人意图的能力，以解决人机协作系统中存在的人机冲突、人机优势融合等问题。提出决策层“以人为主”、执行层“以机为首”的人机协作关系，构建包含驾驶人意图识别模块、基于意图识别的轨迹规划模块与轨迹跟踪控制模块的人机协作一体化控制系统框架，并重点对轨迹规划模块与轨迹跟踪控制模块开展研究。首先，结合双向长短期记忆神经网络（Bi-directional Long Short Term Memory，Bi-LSTM）与注意力机制模型建立换道轨迹规划模型；在改进人工势场算法中引入模型预测控制并建立避险轨迹规划模型。其次，通过开展驾驶模拟器试验建立换道与避险驾驶行为数据集，为拟人化模型训练和模型参数确定提供支撑。然后，综合考虑车辆状态变量、控制输入与输出以及道路结构参数等约束条件，构建基于最优转向前轮输入的线性时变模型预测轨迹跟踪控制器，实现对规划轨迹的精准跟踪。最后，基于驾驶模拟器搭建人机协作系统硬件在环测试平台，对轨迹规划模块与轨迹跟踪控制模块开展硬件在环测试与验证。结果表明：换道与避险规划轨迹光滑且平稳，轨迹跟踪控制过程中，车辆航向角与前轮转角变化平稳；所构建的轨迹规划与轨迹跟踪控制模块在确保安全性前提下可实现不同场景中的车辆运动控制需求。     

基于全弹道控制分析的水下航行器攻击模型视景仿真*

研究并建立高空滑翔水下航行器的虚拟现实的视景仿真系统,分析水下航行器全弹道控制并在视景仿真平台下实现水下航行器全弹道多状态攻击轨迹模型。高空滑翔水下航行器姿态变化快,背景参数复杂,视景仿真中会出现局部模型快速变化或者模型分离的难题。提出采用DOF和Switch节点相结合的方法,利用其Matlab Simulink仿真模型,计算高空滑翔水下航行器的六自由度数据,通过Matlab的“To Workspace”模块将六自由度数据输出并存档。在VC＋＋6．0环境下编写Vega应用程序,读取运动参数,应用LOD技术在不降低显示速度的同时提高仿真视觉效果。仿真实验和测试效果表明,系统实能实现水下航行器在空中滑翔、低空突防、滑翔翼脱离以及水下攻击等多状态的水下航行器运动弹道轨迹和视景仿真效果,以及运动控制参数的同步跟踪,不再会因局部模型快速变化和模型分离而失真。为分析空投滑翔水下航行器的运动轨迹提供了数据支撑和视景平台支持,对展开高空滑翔水下航行器的弹道控制研究和试验具有重要价值。     

基于群组层次分析理论的顾客需求权重确定

确定顾客需求权重是质量功能展开(QFD)的关键环节。论文运用群组层次分析法来确定顾客需求权重,首先建立系统递阶层次结构,获取各专家的两两比较判断矩阵,然后对判断矩阵进行一致性检验,并通过相关算法计算得到综合各个专家意见的判断矩阵,最终确定顾客需求权重。最后以潜艇自卫防空武器系统顾客需求权重的确定为例,验证了用群组层次分析法确定顾客需求权重的可行性。     

公路隧道出入口平面线形一致性检验研究

由于地形、地物等条件的限制,项目选线中隧道洞口段位于回旋曲线上,考虑到洞口段行车的安全,规范对隧道出入口的平面线形一致性有专门的要求,但在实际操作过程中存在一定的困难和分歧。以JTG D20--2006公路路线设计规范中不设缓和曲线的圆曲线最小半径以及回旋曲线最小长度计算出的临界内移值P,提出了一个隧道出入口平面线形一致性检验的定量化判据,即行车道中心线上距洞口3s设计速度行程终点与驾驶员继续按设计时速行驶3s后的位置偏差△D≤临界内移值P,否则就认为不满足一致性要求。     

海底溢油输移扩散的可视化数值模拟系统

为直观研究溢油在复杂水下环境中的动态行为,设计和开发一套海底溢油可视化数值模拟系统(SIMPACT-SOS).系统由数值模型、数据库和图形界面构成,具有地理信息系统(GIS)应用平台、数值建模分析、溢油数值模拟等专业功能.应用算例表明,SIMPACT-SOS系统可为海底沉船溢油、海底输油管道泄漏、海洋石油钻井井喷等水下污染事故的风险评估、应急决策及损害评估提供理论和技术支持.     

船舶航迹跟踪的滑模控制

为了解决船舶路径跟踪中的非线性问题,在建立船舶非线性模型的基础上,采用指数趋近律,设计了船舶轨迹跟踪的滑模控制器,分别进行了动态直线跟踪和环形跟踪仿真试验,仿真结果表明,船舶动态轨迹跟踪性能良好,能精确保持航迹。