基于认知实验选取地标的研究现状分析

认知实验作为研究人类认知世界的科学活动方式之一,地标是辅助人们进行日常寻路与导航的关键要素,从环境中提取合适的地标方法是空间认知研究领域的热点之一。本文从认知实验和面向导航的视角出发,在对国内外大量文献进行分析研究的基础上,系统综述了基于认知实验选取地标的研究进展。首先,介绍了目前主流的各种地图学认知实验方法在地标选取中的应用;其次对眼动实验作为定量探究导航中地标选取行为特点的新方法进行重点分析;最后,总结归纳了各种认知实验在地标选取中的优缺点及存在的问题,对指导今后的地标选取具有一定的借鉴价值打下基础。     

均值漂移与卡尔曼滤波相结合的遥感影像道路中心线追踪算法

基于模板匹配的道路追踪方法是道路提取中较实用的一类方法,但传统模板匹配方法主要以相关系数作为相似性测度,对车辆、树荫等遮挡敏感,不适用于高分辨率遥感影像道路提取。针对这一问题,本文采用一种稳健的相似性测度,设计了一种基于均值漂移的道路中心点匹配算法,克服了传统模板匹配对遮挡敏感的缺点;然后运用卡尔曼滤波,实现高分辨率遥感影像道路中心线追踪。试验表明,该方法能够准确提取高分辨率遥感影像道路中心线,对车辆、树荫等遮挡具有稳健性。     

基于二维码的城市部件移动巡查系统研究

针对市政部门在数字城市建设中提高城市基础部件巡查维护效率的需求,引入二维码技术到城市部件移动巡查系统架构中,剖析系统的主要功能模块,研究二维码技术应用、ArcGIS Server地图服务发布和移动终端定位等系统构建关键技术,设计并实现基于二维码技术的城市部件移动巡查系统。系统达到提高城市部件移动巡查工作效率和质量的效果,为提高城市部件移动巡查工作提供良好的解决方案和思路。     

Robust sliding mode control of a mini unmanned underwater vehicle equipped with a new arrangement of water jet propulsions: Simulation and experimental study

This paper presents dynamical modeling and robust control of a Mini Unmanned Underwater Vehicle (MUUV) equipped with a new arrangement of water jet propulsion. The water jet propulsion includes some advantages comparing with a propeller one, such as, reducing the number of required motors, desired number and arrangement of the propulsions, removing adverse torque and cavitation due to propeller rotation and etc. In order to model the proposed MUUV, the gray box method is used in such a way that the dynamical equation of motion is derived analytically by Euler-Lagrangian method, and then the hydrodynamic coefficients (such as added mass and drag coefficients) are derived by performing some tests in a Computational Fluid Dynamic (CFD) software. The dynamical model is used to simulate the MUUV system and also to design the proposed controllers, which are Feedback Linearization Controller (FLC) and Sliding Mode Controller (SMC). In order to investigate and compare the performance of the MUUV and the applied controllers, three types of tests including a desired signal tracking case and two desired path tracking cases are designed. To do so, a method is presented to obtain the desired signals from a desired path under predetermined conditions. Then, an MUUV prototype is designed and constructed in order to investigate the performance of the proposed water jet propulsions and controllers for regulation and tracking desired signal purpose, experimentally. As it is expected, the simulation and experimental results show better performance of the SMC compared to FLC. Furthermore, the experimental results reveal that the water jet propulsion is implementable to practical prototypes and also can be produced in an industrial level.     

基于GPS的海冰实时监测系统及其应用研究

海冰是高纬度海区特有的海洋现象。运动的海冰具有巨大的能量,对冰区的石油平台、港口堤坝、船只等构成了巨大的威胁,因此实时获取准确的海冰运动信息对于海冰灾害的防治有重要的现实意义。我国海冰为一年海冰,冰体较薄,用于极地的海冰跟踪设备并不适用于我国北方海域。设计并提出了一种基于GPS的海冰定位跟踪系统,系统包含冰上定位发射和接收两个部分。冰上部分质量较轻且外形增加了防滑设计,接收端接收到数据后自动入库,并与地图匹配显示。监测系统于2015-2016年冬季在辽东湾海域进行了应用测试,应用试验表明,该方法能够较好地进行海冰定位与跟踪,定位误差在5 m以内,运行时间较久,较适用于我国薄冰海域。     

煤矿底板注浆多分支水平井卡钻事故处理

煤矿底板注浆多分支水平井因其具有效封堵含水层中的导水通道,解决煤矿底板水对工作面的威胁,对环境破坏小等优点被广泛应用于煤矿底板突水防治中,但受地质条件、水文条件、钻井工艺、施工过程等影响,在施工中易发生事故。以淮北煤田某煤矿底板注浆多分支水平井为例,对该井因二开施工过程不规范引起地层坍塌导致的井下卡钻事故进行分析,在采用常规方式处理无效的情况下,借鉴“油田老井侧钻开窗技术”,不仅解决了卡钻事故,而且确保了后期施工安全。这是侧钻开窗技术在该区处理井下事故的首次成功应用,对该区及国内其他地区处理类似事故具有重要的借鉴和指导意义。     

Surface velocity fields of active rock glaciers and ice-debris complexes in the Central Andes of Argentina

Rock glaciers and transitional ice-debris complexes predominate the Central Andean landform assemblage, yet regional studies on their state of activity and their kinematics remain sparse. Here we utilize the national glacier inventory of Argentina to quantify surface velocity fields of 244 rock glaciers and 51 ice-debris complexes, located in the Cordón del Plata range, Argentina. Applying a feature-tracking approach to repeated RapidEye satellite imagery acquired between 2010 and 2017/18, we find mean displacement rates between 0.37 and 2.61 m year⁻¹ for 149 landforms, while for the remaining 146 features, surface movement remains below our level of detection. We compare our satellite-derived velocity fields with ground-truth data from two local field sites and find closely matching results in magnitude and spatial distribution. With average displacement of one-third of the active rock glaciers and ice-debris complexes exceeding 1 m year⁻¹, the region hosts an exceptional number of fast-flowing periglacial landforms, compared to other mountain belts. Using a random forest model, we test the predictive power of 25 morphometric and topoclimatic candidate predictors for modelling the state of activity of rock glaciers and ice-debris complexes on two different scales. For entire landforms and individual landform segments, constructed along displacement centrelines, we can predict the state of activity with overall accuracies of 70.08% (mean AUROC = 0.785) and 74.86% (mean AUROC = 0.753), respectively. While topoclimatic parameters such as solar radiation and elevation are most important for entire landforms, geometric parameters become more important at the scale of landform segments. Despite tentative correlations between local slope and surface kinematics, our results point to factors integrating slope and distance to the source to govern local deformation. We conclude that feature tracking in optical imagery is feasible for regional studies in remote regions and provides valuable insight into the current state of the Andean cryosphere. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd     

地图矢量数据拓扑关系生成算法

拓扑关系的建立是地图矢量数据管理和更新的重要内容。在综合多种典型拓扑算法优点的基础上,详细描述了拓扑关系生成算法的主要过程,并在线要素互相交断链、结点匹配和特殊情况处理等方面对算法进行了改进。最后以1∶25万济宁市地形图数据进行了实验,结果表明该算法在效率方面优于传统算法。     

联合高低卫-卫跟踪和卫星重力梯度数据恢复地球重力场的谱组合法

GOCE采用的高低卫-卫跟踪和卫星重力梯度测量技术在恢复重力场方面各有所长并互为补充,如何有效利用这两类观测数据最优确定地球重力场是GOCE重力场反演的关键问题。本文研究了联合高低卫-卫跟踪和卫星重力梯度数据恢复地球重力场的最小二乘谱组合法,基于球谐分析方法推导并建立了卫星轨道面扰动位T和径向重力梯度Tzz、以及扰动位T和重力梯度分量组合{Tzz-Txx-Tyy}的谱组合计算模型与误差估计公式。数值模拟结果表明,谱组合计算模型可以有效顾及各类数据的精度和频谱特性进行最优联合求解。采用61天GOCE实测数据反演的两个180阶次地球重力场模型WHU_GOCE_SC01S（扰动位和径向重力梯度数据求解）和WHU_GOCE_SC02S（扰动位和重力梯度分量组合数据求解）,结果显示后者精度优于前者,并且它们的整体精度优于GOCE时域解,而与GOCE空域解的精度接近,验证了谱组合法的可行性与有效性。     

地波雷达目标检测跟踪联合处理粒子滤波方法

针对固定粒子数PF-TBD算法计算量大、复杂环境下地波雷达海上船只目标检测与跟踪性能不佳的问题,本文将粒子滤波方法应用于地波雷达船只目标检测与跟踪中,提出了基于自适应粒子滤波的地波雷达目标检测与跟踪联合处理方法。该方法结合地波雷达回波谱中目标展宽特性,充分利用了地波雷达回波谱中面目标的粒子权重信息来设置粒子自适应采样策略,提高了目标检测和跟踪联合处理的效果。通过地波雷达实测数据的目标跟踪结果及与同步AIS信息的比对分析,结果表明:提出的检测跟踪联合处理方法在对低信噪比、快速机动等复杂环境下的多目标跟踪时,可提高目标整体跟踪性能。