社会转型时期公路工会群众工作探索

文章基于社会转型时期河池公路管理局工会群众工作实际,分析了新时期公路工会群众工作中存在的问题,提出改进公路工会群众工作的对策与建议,以建设服务型、法治型、活力型工会,积极作为服务职工群众。     

基于稳定度指标的分布式驱动车辆转向稳定性控制研究

针对装有轮毂电机的分布式驱动车辆,设计了一种车辆稳定性控制系统,该系统包括上层附加横摆力矩决策和下层转矩分配2个层次.基于滑模控制理论设计了上层β-ω联合控制器,并用修正的五参数菱形法划分车辆相平面的稳定域,基于此设计稳定度指标进行失稳判断与控制比例分配,下层基于动态载荷理论分配附加横摆力矩,优化了控制分配效果,在MA...     

干线公路旧危桥改造若干问题探析

结合干线公路窄桥加宽、旧桥改造施工及监理的实践,就危旧桥梁改造若干问题进行探讨分析,供同行参考,如有不当,不吝指正。     

基于相位分析的超声波噪声信号抑制算法

针对超声波射频（简称RF）信号的特点,确定了一种基于离散傅立叶变换（简称DFT）加窗的相位分析方法。经过对超声波RF信号相位信息的分析,提取出2路超声波信号相位信息,再解析测量误差,提出解决办法。通过噪声抑制算法应用,给出仿真结果及应用实例。     

Transformation Plasticity─The Effect on Metallo-Thermo-Mechanical Simulation of Carburized Quenching Process

IntroductionInelashcorhaersiblestrainaccompaniedbyslidingofcrystalsduetothermalandphasetransformationdilatationiswellknowntointensivelythethedistonionofworkpieceunderqUopching,andsomanynumericalsimulatonsll-7]havebeencAnedoutintheframeworkofmotallochermo-mechwhcsl1].Transformationplasticity(TP),anothekindofbeversiblestrain,isalsorecognizedasoneofdominantparwtersthechngthestr6ssanddistorton,andsomenumcricalcalculationaremadebytakingtheeffectintoconsideration.Figurelschematicallyillustraresthe…     

基于小型圆阵的AUV方向定位算法的研究

水下小型无人系统AUV在海洋探测中起着重要，实现其精准定位与打捞有利于促进海洋经济的发展。传统的具有较高定位精度的装置如长基线等不方便装载与布置，定位效率不高。本文提出一种基于小型圆阵的AUV方向定位算法，被定位的AUV搭载声源，装载在船上的定位系统，采用半径为0.125m的水听器圆阵列，阵元个数为4，水听器阵列接收的信号通过多通道前端处理电路被采集，对每个阵元接收到的信号利用希尔伯特变换相位检测方法检测出各信号的相位恢复无幅度和相位失真的信号，然后使用具有超指向性的反卷积波束形成算法实现AUV方向的准确估计。水池实验表明，小型圆阵系统的相位反卷积波束形成定位算法精度高，定位平均误差为0.233°，主瓣宽度窄，波束平均宽度3.97°。便于装载，相比MUSIC算法具有更好的定位效果。     

浅议广州地铁工程投资控制

文章从广州地铁建设项目的决策阶段、设计阶段和工程实施阶段分别阐述和分析．通过科学的优化管理，在保证质量、进度和安全的前提下，实现对地铁建设工程的投资控制。     

Border crossing delay prediction using transient multi-server queueing models

As a result of the continued increase in travel demand coupled with the need for tighter security and inspection procedures after September 11, border crossing delay has recently become a critical issue with tremendous economic and social costs. The current paper develops multi-server queuing models to estimate border crossing delay in support of a predictive traveler information system for the crossings. Two classes of multi-server models are considered: (1) models with exponential inter-arrival times and Erlang service times; and (2) a more generic model with a Batch Markovian Arrival Process (BMAP) and phase types (PH) services. As a case study, the models are developed based on real-time traffic volume and inspection time data collected at one of the major US–Canada border crossings, the Peace Bridge, and their transient solution is obtained using heuristic methods. For validation, the queueing models’ estimates are compared to the results from a detailed microscopic traffic simulation model of the Peace Bridge border crossing. The comparison shows that the transient queueing model, along its heuristic solution algorithm, is capable of predicting border crossing delay. Finally, a set of sensitivity analysis tests are conducted, and the developed models are incorporated within an optimization framework to help inform border crossing management strategies.     

Second-order models and traffic data from mobile sensors

Mobile sensing enabled by GPS or smart phones has become an increasingly important source of traffic data. For sufficient coverage of the traffic stream, it is important to maintain a reasonable penetration rate of probe vehicles. From the standpoint of capturing higher-order traffic quantities such as acceleration/deceleration, emission and fuel consumption rates, it is desirable to examine the impact on the estimation accuracy of sampling frequency on vehicle position. Of the two issues raised above, the latter is rarely studied in the literature. This paper addresses the impact of both sampling frequency and penetration rate on mobile sensing of highway traffic. To capture inhomogeneous driving conditions and deviation of traffic from the equilibrium state, we employ the second-order phase transition model (PTM). Several data fusion schemes that incorporate vehicle trajectory data into the PTM are proposed. And, a case study of the NGSIM dataset is presented which shows the estimation results of various Eulerian and Lagrangian traffic quantities. The findings show that while first-order traffic quantities can be accurately estimated even with a low sampling frequency, higher-order traffic quantities, such as acceleration, deviation, and emission rate, tend to be misinterpreted due to insufficiently sampled vehicle locations. We also show that a correction factor approach has the potential to reduce the sensing error arising from low sampling frequency and penetration rate, making the estimation of higher-order quantities more robust against insufficient data coverage of the highway traffic.     

北京昌平线二期地铁盾构侧穿桥梁沉降监测分析

采用盾构法施工不可避免会引起地表及建筑物的变形沉降。为了研究盾构侧穿桥梁时对桥梁沉降变形的影响,以北京昌平二期工程盾构侧穿桥梁为例,采集桥桩和地表沉降变化数据,结合盾构推进土压和注浆量,分析桥桩及桥梁周边地表在不同阶段的沉降变形情况。得出:1)当盾构低土压侧穿桥梁时,会引起桥梁横向的差异沉降;2)低注浆率穿越浅覆土层及不良填土层时,隧道正上方范围内的地表仍会发生隆起变形。因此,盾构侧穿时,必须保证合理土压和注浆率,防止桥梁发生断裂裂缝及穿越不良土层时出现地表冒浆。