钢管混凝土拱桥支架法施工技术

以朝阳东大桥为例,简要介绍钢管混凝土拱桥支架法施工工艺及施工要点,经实践证明支架法施工经济简便、安全可靠.     

捣固车信号校准系统的设计与实现

捣固车信号校准系统关系到捣固车运行的准确性与可靠性.采用CAN总线,完成了基于AT89C52及SJA1000芯片的信号校准系统的软、硬件设计.该系统具有远程操作等控制功能,能显示并校准各个通道信号.实验结果表明:所研制的系统满足设计要求,可提高捣固车的工作效率及可靠性.     

基于CAN总线的汽油机管理系统标定平台开发

将CAN转USB接口技术应用于发动机标定系统中,实现了标定主机和发动机各待标定电控单元之间的实时准确数据通信,具有连接简单、传输速率高和控制系统扩展性好等优点。在优化过程中采用了Bayesian算法,缩短标定时间并提高了标定精度。最后针对WF4C27F-E汽油机进行了标定试验,获取了充量系数和点火提前角MAP图。     

红旗CA7180/CA7182排放的标定匹配

结合CA7180／7182红旗轿车的标定工作,综述了汽油机采用一级三效催化剂加闭环电子控制的措施,使排放达到欧Ⅱ法规要求的发动机电控系统标定匹配方法,并给出了红旗轿车的标定匹配结果。     

Calibration of response amplitude operators based on measurements of vessel motions and directional wave spectra

A vessel's response to waves is dependent on a large number of parameters, some of which are both frequency and direction dependent. To predict vessel response, these parameters are used to construct response amplitude operators (RAOs) that act as transfer functions between the directional wave spectra and the motion spectra of the vessel. In particular situations, however, vessel motions predicted using RAOs calculated with general-purpose radiation-diffraction codes and measured wave spectra are found to deviate from measured vessel responses. To address this problem, a methodology for calibrating RAOs based on measurements of the directional wave spectra and vessel motions is proposed. Use is made of a vector fitting method through which the frequency dependent hydrodynamic properties of the vessel can be approximated by a ratio of two polynomials, thus greatly reducing the number of parameters that need to be calibrated. The reduced set of parameters is subsequently related to previously identified causes of RAO inaccuracy in order to arrive at optimization algorithms for identifying more accurate RAOs from the measurements. It is shown that the RAOs can be improved with accuracy in situations where the discrepancies are caused by imprecise estimates for the vessel's radii of gyration, center of gravity, or viscous damping. When the discrepancies in the RAOs are related to the potential mass, damping and wave forces, however, the problem becomes highly non-convex and it is not possible to find a unique RAO that satisfies the data.     

基于CCP协议的ECU标定系统上位机设计

为了提高标定系统开发研究的效率,文章采用工业界广泛认可的标定规范ASAP作为标定系统软件开发标准,采用CCP协议作为标定系统的应用层协议,描述了上位机软件的3大主要模块(界面功能模块、CCP驱动模块和CAN驱动模块)及其开发流程。经反复调试,该上位机软件实现了数据实时监控和参数标定等功能。基于CCP协议的标定系统通信稳定可靠,且传输速率快,其应用推广有利于促进标定系统研究的规范性和通用性。     

Trajectory data reconstruction and simulation-based validation against macroscopic traffic patterns

This paper shows that the behavior of driver models, either individually or entangled in stochastic traffic simulation, is affected by the accuracy of empirical vehicle trajectories. To this aim, a “traffic-informed” methodology is proposed to restore physical and platoon integrity of trajectories in a finite time–space domain, and it is applied to one NGSIM I80 dataset. However, as the actual trajectories are unknown, it is not possible to verify directly whether the reconstructed trajectories are really “nearer” to the actual unknowns than the original measurements. Therefore, a simulation-based validation framework is proposed, that is also able to verify indirectly the efficacy of the reconstruction methodology. The framework exploits the main feature of NGSIM-like data that is the concurrent view of individual driving behaviors and emerging macroscopic traffic patterns. It allows showing that, at the scale of individual models, the accuracy of trajectories affects the distribution and the correlation structure of lane-changing model parameters (i.e. drivers heterogeneity), while it has very little impact on car-following calibration. At the scale of traffic simulation, when models interact in trace-driven simulation of the I80 scenario (multi-lane heterogeneous traffic), their ability to reproduce the observed macroscopic congested patterns is sensibly higher when model parameters from reconstructed trajectories are applied. These results are mainly due to lane changing, and are also the sought indirect validation of the proposed data reconstruction methodology.     

基于单目机器视觉的船舶测距定位原理研究

利用透视投影几何关系和摄像机内部参数,计算船舶与各陆标之间的距离,提出一种基于单目机器视觉的船舶测距定位方法。仿真结果表明,该方法与传统的陆标定位方法相比,具有简易、实时、受海况影响小的优势,可满足全封闭舰船陆标定位要求。     

铁路罐车量值传递方法分析

铁路罐车量值传递方法有几何测量法、比较法。论述了几何测量法和比较法,并对它们的量值传递结果进行了分析。一般情况下采用几何测量法检定铁路罐车,比较法用于仲裁检定。     

The principles of calibrating traffic microsimulation models

Traffic microsimulation models normally include a large number of parameters that must be calibrated before the model can be used as a tool for prediction. A wave of methodologies for calibrating such models has been recently proposed in the literature, but there have been no attempts to identify general calibration principles based on their collective experience. The current paper attempts to guide traffic analysts through the basic requirements of the calibration of microsimulation models. Among the issues discussed here are underlying assumptions of the calibration process, the scope of the calibration problem, formulation and automation, measuring goodness-of-fit, and the need for repeated model runs.