红外车辆分离子系统的设计和性能分析

在机动车磁卡收费系统中,红外车辆分离子系统是一种重要设备,它是由平行等距红外线族构成的平面检测系统,其性能直接影响收费系统的正常运转。本文介绍该子系统的设计并对系统性能进行分析,得出:子系统采取相关检测技术后,不仅能有效地抑制外界干扰、噪声,还具有抗相邻红外信号干扰能力。     

地铁沿线建筑内噪声多维度感受影响机制

随着城市铁路系统的快速发展,铁路沿线建筑内人群对地铁运行产生噪声的抱怨逐渐增多,为控制室内地铁噪声对人群所产生的负面影响,有必要对地铁噪声产生的多维度负面情绪进行评估。采集了79名受试者对建筑内地铁噪声的多维度负面感受(压抑感,不舒适度和不满意度),基于偏最小二乘法分析了主客观影响因素对多维度负面感受的作用机制,并比较了多维度负面感受在反映地铁噪声影响上的差异。结果表明,多维度负面感受主要取决于主观响度和声学参数,活动干扰度、地铁噪声的敏感度、厌烦度和适应性的影响明显更弱;3个多维度负面感受中,相比于压抑感,不舒适度和不满意度受主观响度的影响轻微更显著,在相同的主观响度感受下,不满意度等级最高。 该文可以为地铁沿线建筑物内噪声负面感受的评价和改善提供参考。     

Combustibles,fuels and their combustion products: A view through carbon isotopes

Stable (i.e. non-radioactive) carbon-isotope composition (δ¹³C) in fuels has been extensively used as an indicator of the processes leading to the generation of their parent crude-oil. With the example of those used in Paris (France), this preliminary study isotopically characterizes fuels and combustibles, as well as the isotopic relations existing with their combustion by-products, i.e. gases (CO₂) and particles (bulk carbon). Results show that δ¹³C in fuels is clearly related to their physical state, with natural gas being strongly depleted in ¹³C while coal yields the highest δ¹³C, and liquid fuels display intermediate values. This relation is also valid for combustion gases, although δ¹³C values of combustion particles form a homogeneous range within which no clear distinction is observed. Combustion processes are accompanied by carbon-isotope fractionation (noted Δ¹³C) resulting from the combustion being incomplete. Carbon-isotope fractionation is strictly negative (Δ¹³C = ?1.3‰) during the formation of combustion gases, but generally positive in particle formation even if values close to zero are observed. Using simple mixing equations for describing the closed system formed by fuel, CO₂ and carbonaceous particles, we discuss the carbon budget for spark-ignition (unleaded gasoline) and diesel engines. Stable carbon isotopes corroborate the already-proved superior efficiency of diesel combustion mode compared with spark ignition, as carbon is preferentially transformed into CO₂.     

新形势下中国移动城域传送网演变之路

面对急剧变化的业务需求,中国移动城域传送网该何去何从？本文从网络结构、新技术演进等方面进行了分析和研究,并提出了其网络演进思路和方案,供网络规划建设人员参考。     

新一代运载火箭时序仿真系统信号完整性分析

新一代运载火箭时序仿真系统具有数字电路速度快、集成度高的特点,系统要求发出多路高精度时序、时串信号以满足新一代运载火箭地面测试设备的检查与校准需求,因此信号完整性问题在系统设计中不容忽视。针对仿真系统的典型模块(USB 3.0 Super-speed差分线、FPGA外设数据走线、时钟走线)进行建模分析仿真得出PCB硬件电路设计参数,给出时序仿真系统设计信号完整性问题的抑制和解决方法,优化了板级信号质量,改善系统可靠性、工作连续性和输出精度,可有效提高新一代运载火箭测试效率和测试可靠性。     

基于多模差分融合的高速车辆定位算法

针对车辆高速运动下定位延时大、精度低、稳定性差的问题,发挥GPS、RSSI和INS三种定位模式的各自优势,将GPS差分校准算法与RSSI测距相结合求解横坐标,将RSSI测距与INS惯导迭代算法相结合求解纵坐标,提出了一种适合高速运动车辆的多模差分融合精确定位算法。以四车道的高速路为场景进行了仿真实验,当车速为70km/h时,跟踪误差<1m,定位延时<0.2s。实验结果表明,该算法可实现车身级和车道级定位,在精确交通诱导、车辆防撞等智能交通领域具有应用前景和推广价值。     

一种高准确率的交通监控视频车辆检测算法

针对高速视频监控的车辆识别易受几何变换影响且准确度不高的问题,提出了高效的阴影去除和车辆分类两种视频处理算法来提高车辆识别性能。利用阴影区域前景和背景的对比度参数进行有效的阴影去除;利用Hu不变矩表征车辆,从而克服了几何变换的影响。对比试验结果证明,本算法具有较高的阴影检测性能和极佳的车辆分类性能,明显优于其他同类型算法。     

Coverage path planning for UAVs based on enhanced exact cellular decomposition method

In this paper, an enhanced exact cellular decomposition method to plan the coverage path of UAVs in a polygon area is proposed. To be more specific, the contributions of the paper are: firstly, the turning motion of UAVs is shown to be less efficient from the viewpoints of route length, duration and energy. Secondly, the problem of coverage Path Planning (CPP) in a convex polygon area is transformed to width calculation of the convex polygon, and a novel algorithm to calculate the widths of convex polygons with time complexity of O(n) is developed. The path of the least number of turns for an UAV based on the widths of convex polygons is devised. Thirdly, a convex decomposition algorithm for minimum width sum based on the greedy recursive method which revolves around decomposing the concave area into convex subregions is developed. It is proved that the algorithm is a polynomial time algorithm. To avoid unnecessary back and forth motion, some entirely adjacent subregions are combined. Finally, comparing different weights of two joint-points, a subregion connection algorithm based on minimum traversal of weighted undirected graph is proposed to connect the coverage paths of the subregions. Simulation results show that the proposed method is feasible and effective.     

城域网的光缆线路设计

根据城域网的定位及作用，对城域光网络的结构、组网原则和光纤选用等问题进行了讨论。     

浅谈南京地铁 ATS 系统 SINAUT Spectrum 平台

南京地铁ATC(列车自动控制)系统采用Solaris系统环境、SINAUT Spectrum控制实现平台和VICOS控制界面。目前被关注比较多的是Spectrum的操作系统环境:Solaris操作系统以及在Spectrum基础上的VICOS控制平台。文中根据南京地铁一号线ATS系统,描述了SINAUT Spectrum的运用、系统构架、系统组成以及各个组件的功能。