地面激光扫描仪的精度影响因素分析

尽管地面三维激光扫描技术正被越来越多地应用于多个领域,但对其测量数据的精度评定,至今尚缺乏必要的理论及方法支持。从分析直接测量数据出发,对该类测量仪器误差的主要来源及其对测量数据的影响情况进行了详细分析,构建了地面三维激光扫描仪单个扫描点测量数据的精度评价模型。该模型为基于地面三维激光扫描仪高精度测量项目(如变形监测)的测量成果精度评定,以及测量方案的优化设计提供了所必需的理论基础。     

Advanced permanent magnet motor drive modeling for automotive application under matlab/simulink environment

This paper proposes an advanced permanent magnet (PM) motor drive modeling for dynamic analysis of automotive control systems with PM motor drives. To enhance the reusability of the proposed PM motor drive model, each component is modeled in an object-oriented manner according to the physical partitioning of a real drive system, and userfriendly and well-organized interfaces are also proposed. These characteristics enable this model to be used as a kind of a programming library. A multi-level modeling strategy is also proposed, which helps make a compromise between model accuracy and simulation speed without structural modification of the system model. The model and modeling strategy developed allow for a comprehensive analysis of each component and dynamic analysis of the total system. System simulation results show the practical effectiveness of the proposed modeling strategy.     

Powertrain design and experiment research of a parallel hybrid electric vehicle

The powertrain of an ultra-capacitor-based parallel hybrid electric vehicle (HEV) was developed. Innovations, such as the engine management system, floating ISG (Integrated Starter and Generator), electronic-controlled double-clutch system and dual-driven air conditioning system were realized. Hybrid control strategies to improve the fuel economy and reduce emissions were analyzed briefly. In order to ensure the vehicle emission performance, the engine management system calibration was performed. The vehicle emission test was also conducted, showing that the vehicle emission satisfied the EURO III standard and has great potential for improvement. The hybrid start test was introduced in detail. We realized the hybrid function and start parameter optimization of the engine and ISG.     

LM-CDBN超高层变形预测模型的构建与应用

为提高超高层建筑变形预测精度,对附有条件的深度信念网络(conditional deep belief network,CDBN)模型中权值及阈值调整方法进行了改进,使用LM (Levenberg-Marquardt)算法作为新的模型定权机制,构建了LMCDBN网络模型;将构建的LM-CDBN超高层变形预测模型应用于一座298 m超高层建筑中;然后用训练误差、预测值拟合度、预测结果稳定性组成的综合评价体系对模型进行了评价;最后,将LM-CDBN模型分别与深度信念模型(deep belief network,DBN)、极限学习机(extreme learning machine,ELM)、基于无迹卡尔曼滤波的支持回归向量机(unscented Kalman filter-support vector regression,UKF-SVR)进行了预测结果对比.结果表明:在超高层建筑的变形预测中,相比DBN、ELM和UKF-SVR,LM-CDBN预测精度分别提升了32%、55%及24%,模型的信息提取稳定性及处理时变系统非线性问题的泛化能力得到了提高.     

Oversaturation Inherence and Traffic Diversion Effect at Urban Intersections through Simulation

Conventional approaches of signal control optimization and geometric channelization may not be an inappropriate solution to an oversaturated urban intersection, especially where physical expansion is limited by the intensive land-use development around it. Traffic diversion strategy may be an optional solution; however, it is greatly dependant upon identification of the traffic movements that need diversion and the existence of parallel or accessible detour routes that are capable of accommodating the diverted traffic without bring adverse impact on the diversion routes. Obviously, these factors are difficult to be determined through analysis of the field observations alone. This paper presents a study of using simulation-based approach combined with analysis of observed data to identify oversaturated intersection movements needed for diversion and test the traffic diversion effect in the roadways that have potential to bear the diverted traffic. The proposed approach is discussed through a practical case study at the intersection of Galbraith Avenue and Colerain Avenue (US-27), Ohio. The effect of such option is evaluated using a state-of-the-art microscopic traffic simulation system VISSIM, intersection analysis software programs, Highway Capacity Software (HCS 2000), and Synchro. The optimum percentage of traffic that is desired to be diverted at the inlet to minimize the delay while keeping shorter travel time is evaluated for the concerned intersection. The evaluation results imply a successful option that has great potential to put into practice. Finally, signage countermeasures are discussed for implementing the diversion strategy.     

Dynamic Stability of Vehicle Systems via Poincaré Maps

Computer simulations of a driven vehicle are performed to assess and quantify the automobile stability. The analytical methodology is based on PoincarS maps and Floquet theory, which are commonly used to investigate the stability of periodic systems. The approach accommodates the study of the complex dynamics of vehicle locomotion under various configurations of the system. The proposed method does not require any knowledge regarding the inner structure of the vehicle model. Kinematic data is simply collected at the specific instants to conduct the analysis. It is found that this method has the potential for real time warning and control of vehicle instabilities.     

A disaggregated land use—transport model for Delhi,India

A Lowry-type land use-transport model stratified both by socio-economic group and urban sub-region is described. The parameters of this model are calibrated from a 1969 urban travel survey conducted in Delhi. Parameter magnitudes are estimated for several versions of the model and the qualities of these calibrations are reported. Applications of the calibrated models to the analysis of alternative development concepts for the Delhi urban region are described.