Fractional partial differential equation denoising models for texture image

In this paper,a set of fractional partial differential equations based on fractional total variation and fractional steepest descent approach are proposed to address the problem of traditional drawbacks of PM and ROF multi-scale denoising for texture image.By extending Green,Gauss,Stokes and Euler-Lagrange formulas to fractional field,we can find that the integer formulas are just their special case of fractional ones.In order to improve the denoising capability,we proposed 4 fractional partial differential equation based multiscale denoising models,and then discussed their stabilities and convergence rate.Theoretic deduction and experimental evaluation demonstrate the stability and astringency of fractional steepest descent approach,and fractional nonlinearly multi-scale denoising capability and best value of parameters are discussed also.The experiments results prove that the ability for preserving high-frequency edge and complex texture information of the proposed denoising models are obviously superior to traditional integral based algorithms,especially for texture detail rich images.     

湛江电网故障统计分布及台风演化分析

研究湛江电网故障统计分布规律,发现湛江电网故障具有明显的幂律特性,去除故障极值日的数据呈指数分布.而故障极值日均伴有极端天气,表明湛江电网故障的幂律特性因极端天气引发.     

窄带滤光片光学极值法直接监控的光学设计

窄带滤光片是应用于光谱学、激光、天文物理学、通信等各个领域的光学组件,精确控制每一层膜厚是制备滤光片的困难所在.采用光学极值法直接监控工件,可以同时制备多件滤光片.设计了监控光路和信号获得电路,通过探测到的测试信号,监控薄膜膜厚,实现了直接监控.     

What localizes beneath: A metric multisensor localization and mapping system for autonomous underground mining vehicles

Robustly and accurately localizing vehicles in underground mines is particularly challenging due to the unavailability of GPS, variable and often poor lighting conditions, visual aliasing in long tunnels, and airborne dust and water. In this paper, we present a novel, infrastructure‐less, multisensor localization method for robust autonomous operation within underground mines. The proposed method integrates with existing mine site commissioning and operation procedures and includes both an offline map‐building process and an online localization algorithm. The approach combines the strengths of visual‐based place recognition, LIDAR‐based localization, and odometry in a particle filter fusion process. We provide an extensive experimental validation using new large data sets acquired in two operational Australian underground hard‐rock mines (including a 600m‐deep multilevel mine with approximately 33 km of mapping data and 7 km of vehicle localization) by actual mining vehicles during production operations. We demonstrate a significant increase in localization accuracy over prior state‐of‐the‐art SLAM research systems and real‐time operation, with processing times in the order of 10 Hz. We present results showing a mean error of 0.68 m from the Queensland Mine data set and 1.32 m from the New South Wales Mine data set and at least 86% reduction in error compared with prior state of the art. We also analyze the impact of the particle filter parameters with respect to localization accuracy. Together this study represents a new approach to positioning systems for currently deployed autonomous vehicles within underground mine environments.     

软土地区旧桩拔除技术和新建桩基础调整方案及施工措施

结合天津南开区某地块定向经济适用房项目,介绍其在基础施工中遇到旧预制方桩时,采用全套管高压喷气、射水振动沉管施工工艺清孔拔桩,并对该工艺进行分析得出:该拔桩施工工艺适用于软土地区旧桩拔除项目;并针对旧桩孔无法回填压实、部分新建桩基础与拔除旧桩孔距离较近等原因导致钻孔倾斜、串孔等问题,提出远离旧桩位置或调整至旧桩桩心位置等方法调整桩位,并采用加大桩径、增设承台等调整方案承担因调整桩位而产生的上部偏心荷载;采用拌和白灰、分层压实、回填静置等措施提高回填土的密实度,采用保证垂直度和调节泥浆配合比等措施,以改善不良施工条件,得出适当增加混凝土充盈系数保证成桩质量等施工经验,为后续类似工程提供借鉴。     

一种基于并联机构的航天器姿态模拟装置的设计开发

航天器发射升空前进行地面测试和试验是航天器研制过程中的重要环节。文中针对一种基于并联机构的姿态模拟装置的设计开发,从位置分析、速度分析和虚拟样机的建造和仿真分析等方面对3UPS-PU并联机构进行研究,完成姿态模拟装置的设计,为航天器装配、试验和测试设备的设计提供一种新的思路。     

依据角度位置变速的铺匀器控制系统

用角度测量传感器，检测铺匀器的角度变化，并用新型的电、液控制技术，实施了对铺匀器的变速控制。此设计经实际使用，效果良好。     

滑动式双工位装模机构设计

介绍了工程机械车轮热压滑动式双工位装模机构的设计、功能及其应用 ,经反复试验及生产实践证明 ,这种工艺方法切实可行 ,压制出来的产品完全符合设计要求 ,从而成功解决了热压件两道工序间快速切换的技术难题     

国外全位置自动TIG管焊机中的一种新型弧长自动控制系统

管子全位置自动TIG焊时，弧长控制功能是确保焊接质量的关键，尤其在管径、壁厚公差大时，更显重要。本文介绍了POLYSOUDE公司全位置自动管焊机上的一种利用弧压传感反馈的自动控制系统。通过反复实测，证实了该系统具有很高的灵敏度和响应速率。     

A global cutter positioning method for multi-axis machining of sculptured surfaces

Traditional cutter positioning methods have defects of global errors and incomplete optimization. Because of using local differential geometry and focusing on the cutting contact point, these defects cannot be avoided and will deteriorate accuracy in precision machining. The authors presented the conception of actual cutting edge of a toroidal mill which was extended from cutting contact point, and pointed out its importance in programming. Instantaneous cutter position error (ICPE) was also investigated. A new global method based on the ICPE curve was presented. Taking the relationship between surface and cutter into consideration thoroughly, this global method shows many advantages which have been verified by simulation and cutting tests.