侧吹气体对不锈钢薄板CO2激光焊接过程的影响

为了研究侧吹辅助气体对CO2激光焊接过程的影响及其机理,在不锈钢薄板CO2激光焊接过程中,用高速数字摄像机拍摄了不同侧吹工艺参数下等离子体的动态变化过程。对比分析了侧吹工艺变化对等离子体行为和焊缝形貌的影响。结果表明:顶吹气流和侧吹气流的合流角约为40°时焊缝背面熔宽最大,喷嘴高度和流速变化对薄板激光焊接过程有显著的影响;薄板CO2激光焊过程中工件表面上方的等离子体云团有两种典型的形态,即焊透时出现体积较小的等离子体云团和未焊透时出现的体积较大的等离子体云团。     

基于遗传算法的交易中心停车场优化设计

根据某交易中心大型停车场的实际情况 ,并利用大型客车和轿车的长度、宽度、最小转弯半径等数据 ,建立了停车场优化停车设计模型 ,采用遗传算法进行求解 ,得到了停车场的最优停放布局和车位排列角度的优化结果 .本文优化设计的思想、方法和结果对其他大型停车场优化设计也有一定的参考价值 .     

Toward Cloud-Based Parking Facility Management System: A Preliminary Study

An e-tag used on the freeway is a kind of passive sensors composed of sensors and radio-frequency identification (RFID) tags. The principle of the electronic toll collection system is that the sensor emits radio waves touching the e-tag within a certain range, the e-tag will respond to the radio waves by induction, and the sensor will read and write information of the vehicles. Although the RFID technology is popularly used in campus management systems, there is no e-tag technology application used in a campus parking system. In this paper, we use the e-tag technology on a campus parking management system based on the cloud-based construction. By this, it helps to achieve automated and standardized management of the campus parking system, enhance management efficiency, reduce the residence time of the vehicles at the entrances and exits, and improve the efficiency of vehicles parked at the same time.     

基于ARM的停车场车辆管理系统

为了实现基于ARM的停车场车辆管理系统,本文采用Cortex-M3内核的STM32微控制器,以此为核心部署了超声波模组作为车辆检测器,液晶屏作为信息显示器,步进电机作为道闸控制器,以及智能卡读写器。为了便于管理员使用,在PC上用VB编写了图形界面,配合Access数据库通过串口对系统进行管理。测试系统功能结果能够完成车辆在停车场的进出场流程,由此验证了该套低成本解决方案的可行性,实用性。     

Random sequential bisection and its associated binary tree

Summary Random sequential bisection is a process to divide a given interval into two, four, eight, ... parts at random. Each division point is uniformly distributed on the interval and conditionally independent of the others. To study the asymptotic behavior of the lengths of subintervals in random seqential bisection, the associated binary tree is introduced. The number of internal or external nodes of the tree is asymptotically normal. The levels of the lowest and the highest external nodes are bounded with probability one or with probability increasing to one as the number of nodes increases to infinity. The associated binary tree is closely related to random binary tree which arises in computer algorithms, such as binary search tree and quicksort, and one-dimensional packing or the parking problem.     

基于LabVIEW的车位管理系统实训设计方案

本文基于NI-cRIPO 9025可编程控制器,通过反射式红外光电传感器和触发按钮模拟停车场车辆的出入和泊位信息,利用LabVIEW可视化程序对整个过程进行数据采集和状态监控.整体设计简洁明了,可作为传感器和电子技术课程的综合实验实训项目应用于高职专业课程的实践教学.     

基于超声波与无线传感技术的车位信息检测器的研究

本项目开展的是利用用超声波技术和无线传感技术进行车位检测器的开发与研究,信息感知部分采用超声波技术,改变常用红外线传感器、涡流传感器等易受外界因素影响或安装复杂问题,数据传输部分改有线为无线通信技术,施工效率高,成本低.此项技术是对当前停车诱导管理系统中数据采集关键技术的提升和补充.     

Parking with density

We study parkings with n places, where m(n) cars are placed according to a nonuniform probability. The aim of this paper is to show a threshold function (depending on the distribution) for the emergence of a giant component. The size of the largest blocks of consecutive occupied places and the total displacement of the cars are also studied. ©2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 364–380, 2001.     

三维引力辅助解析分析方法研究

针对星际探测中的引力辅助技术,基于二体问题,导出了三维引力辅助前后飞行器速度、能量、角动量和轨道倾角与引力辅助参数之间的解析公式. 以进行木星引力辅助为例,将解析公式计算的结果与基于圆型限制性三体问题的数值仿真结果进行了对比,各项绝对误差小于0.01,除极少数情况外,相对误差均小于0.7%. 分析结果表明导出的解析公式与实际情况对比具有较高的精度,可以满足引力辅助轨道初步设计的需要. 为了讨论和应用上的方便,对导出的公式进行了简化,据此进一步讨论了引力辅助参数对引力辅助效果的影响.     

一种基于卷积神经网络的360环视系统停车位检测设计

针对传统汽车视觉系统所存在的视野有限的缺陷,文章提出了一种基于卷积神经网络的360环视系统停车位检测方法。该系统通过安装在车身四周的4个鱼眼摄像头来获取车身所处环境信息,再对摄像头捕获的图片进行畸变矫正与逆透视变换,由拼接技术生成环视鸟瞰图;在此基础上,设想出一种全新的停车位检测方法,即利用卷积神经网络对环视鸟瞰图进行检测和识别。