A Control-Point-Based Sweeping Technique

This article presents a general sweeping technique for nonuniform rational B-splines. This operator allows sweeps with several cross sections along a 3D path. One can scale the cross sections along the path according to the shape of a profile curve. The definition of the resulting surface is inherited from the initial curves, and you compute its control mesh from the control polygon of these curves. We shall consider several special cases, like straight lines and rational curves; characteristics of circles and straight lines are preserved.     

Sweeping体的离散化原理

本文主要介绍FSMTS中所采用的Sweeping体素的离散化原理。首先讨论了体素离散化的“拓扑有效性”和精度要求,并在此基础上提出了依据主曲率控制离散点密度的方法。其次研究了离散化过程中的三种活动标架,提出了在扫动过程中如何描述截面变化规律的各种策略。最后推导出Sweeping体的合法性检验判据。     

侧扫雷达的流速测验不确定度分析与研究

针对提高侧扫雷达测流系统河流表面流速测验精度,关键在于确定影响侧扫雷达流速测验不确定度因素的情况,结合雷达系统理论设计,分析侧扫雷达产生不确定性的理论原因,包括收发宽波束带来的天线方向展宽效应、河面随机起伏及系统参数设计引起的不确定度等。对侧扫雷达实测数据进行分析,证实系统不确定度的产生对雷达数据频谱的影响,验证不确定度在测流时对测量信号谱宽的影响效应。针对采样不确定度,采用基于点模式的数据采集方法和分析策略,通过配置不同采样的数据集,有效降低测流不确定度,提高雷达数据质量。测站侧扫雷达系统的实测流速数据分析表明：按照相关理论对应要求设置参数,侧扫雷达可取得较好的表面流速测验精度和稳定性,能够满足水文测验的要求,更好地服务于水文测报工作。     

扫雷游戏的设计与实现

本文根据"自顶向下,逐步求精"的软件设计方法,针对windows自带的扫雷游戏进行了总体设计、详细设计,并采用C语言在VS 2019平台上利用Easyx图形库进行编程实现,游戏运行效果良好.     

BMSweep: Locating Interior Nodes During Sweeping

BMSweep is a new algorithm to determine the location of interior nodes while generating hexahedral meshes using the volume sweeping method. Volume sweeping is performed on two and one half-dimensional volumes by identifying a ‘source’ surface which is meshed with quadrilaterals. These quadrilaterals are then swept through the volume towards a ‘target’ surface generating layers of hexahedra along the way. BMSweep uses background mesh interpolation to locate interior nodes during sweeping. The interpolation method provides for quality element creation, while allowing the volume boundary to vary. The cross-section of the volume can vary along the length of the sweep, the sweep path need not be linear, and the source and target areas need not be flat. Three dimensional volumes can be swept using BMSweep after being decomposed into two and one half-dimensional subvolumes.     

一种优先级扫描的Dyna结构优化算法

不确定环境的时序决策问题是强化学习研究的主要内容之一,agent的目标是最大化其与环境交互过程中获得的累计奖赏值.直接学习方法寻找最优策略的算法收敛效率较差,而采用Dyna结构将学习与规划并行集成,可提高算法的收敛效率.为了进一步提高传统Dyna结构的收敛速度和收敛精度,提出了Dyna-PS算法,并在理论上证明了其收敛性.该算法在Dyna结构规划部分使用优先级扫描算法的思想,对优先级函数值高的状态优先更新,剔除了传统值迭代、策略迭代过程中不相关和无更新意义的状态更新,提升了规划的收敛效率,从而进一步提升了Dyna结构算法的性能.将此算法应用于一系列经典规划问题,实验结果表明,Dyna-PS算法有更快的收敛速度和更高的收敛精度,且对于状态空间的增长具有较强的鲁棒性.     

近似查询中重叠区域的扫描计算

根据R*树节点硬盘主引导记录(MBR)特征,在不改变最小外包矩形特征的前提下,通过区域扫描对正交MBR重叠区域边界建立二叉线段树,以此为基础分别计算面积和周长,有效改善了R*树节点结构。理论分析和实验均表明,与未经过重叠区域计算的R*树相比,经计算的R*树节点比较次数平均下降了近60%,准确率提高了约60%。     

多步截断优先扫描强化学习算法

研究了优先扫描的强化学习方法,通过定义新的迹,把多步截断即时差分学习用于集成规划的优先扫描强化学习,用多步截断即时差分来定义扫描优先权,提出一种改进的优先扫描强化学习算法并进行仿真实验,实验结果表明,新算法的学习效率有明显的提高。     

一种扫地机器人路径规划的改进算法

扫地机器人现有的各种路径规划对定位、航迹推算提出了严格的要求,路径计算量及规划难度也随即增大;而简单的随机覆盖法却存在着低覆盖率及高重复率的缺点.为了避免上述各种缺陷,提出了一种路径规划的改进算法,经过扫地机器人验证平台的测试,利用此种改进算法进行路径规划,不仅避免了上述各种缺陷,同时还能够根据环境的相关特征信息做出更进一步的优化.     

Sweeping of an object held by a robotic end-effector

A broadly applicable formulation for calculating the swept volume generated by an object held by a manipulator's end-effector is presented. While the problem of determining the workspace of a robot arm has been extensively addressed in the literature, this rarely addressed problem is of significance to path planning, collision detection, plant layout, and robot design. The totality of points touched by a geometric entity moved in space using a number of joints is defined as the swept volume. The formulation and accompanying experimental code are presented and are aimed at providing the reader with a replicable computer algorithm. Calculating the swept volume is based on The Implicit Function theorem and is shown to be any number of degrees of freedom yielding the exact representation of the swept volume. By considering the sweep equation as a vector function defined on a manifold (possibly with boundaries), it is shown that stratification of the various sub-manifolds yields varieties that can be depicted in R³. A measure of the computational complexity is presented to give the reader a sense of the robustness of this method as well as its difficulties. An experimental computer code is developed using a symbolic manipulator that performs the automated calculations necessary to calculate the varieties and to visualize the manifold.     

扫频干扰的自适应时变抑制研究

在DSSS系统中,提出一种基于修正离散Chirp-Fourier变换(MDCFT)的扫频干扰自适应时变抑制算法。该算法采用MDCFT估计扫频干扰的参数,构造了实时性强的自适应时变干扰剔除器,推导了MDCFT检测扫频干扰的输出信噪比的闭合表达式。与Wigner-Hough变换(WHT)估计扫频干扰时的非线性损失相比,输出信噪比提高了3 dB,并给出了误码率的闭合表达式。数值仿真表明了理论分析的正确性和该方法的有效性。     

多分支拖曳扫雷系统姿态仿真模型

为分析多分支、多部件拖曳扫雷系统的水下姿态,为提高系统的稳定性,采用简化为多点受力的刚性杆系模型,以欧拉角表示系统位形,建立了系统的虚位移关系和流体阻力算法,用连通矩阵解决了分支表达和计算问题,基于虚功原理建立了矩阵形式的系统稳态方程,简化为求解N个二元非线性方程组得到系统的稳态位形.实例计算结果表明模型能吻合实际情况,能准确反映系统结构变化对稳定姿态的影响,可为类似系统的设计和使用提供依据.     

一种改进的求解输运方程的并行Sn扫描算法

非结构网格上求解粒子输运方程的可扩展并行算法是一个亟待解决的课题。本文在文献[1]并行流水线勖扫描算法的基础上提出了一种改进算法。改进后的算法可以有效降低原算法对并行机通信延迟的依赖,减少程序运行的通信时间,达到了缩短并行计算时间和提高并行性能的目的。针对二维粒子输运问题进行的数值实验表明,从64扩展到256个处理机时,加速比呈线性增长,改进算法比原算法的并行计算时间最大减少了19％。     

A Fast Sweeping Method for Computing Geodesics on Triangular Manifolds

A wide range of applications in computer intelligence and computer graphics require computing geodesics accurately and efficiently. The fast marching method (FMM) is widely used to solve this problem, of which the complexity is O(Nlog N), where N is the total number of nodes on the manifold. A fast sweeping method (FSM) is proposed and applied on arbitrary triangular manifolds of which the complexity is reduced to O(N). By traversing the undigraph, four orderings are built to produce two groups of interfering waves, which cover all directions of characteristics. The correctness of this method is proved by analyzing the coverage of characteristics. The convergence and error estimation are also presented.     

Sweeping体的拓扑结构与精确B—Rep反算策略

本文根据五种造型法则:平行扫法则、回转扫法则、箱体法则、异形体法则和曲面立体法则的离散化原理,提出了Sweeping体的拓扑结构的生成方法。讨论了离散化多面体边界的几何属性码和CSG-索引方法,以及基于这种几何属性码和CSG-索引的精确B-Rep反算策略。     

非结构网格上求解中子输运方程的并行流水线Sn扫描算法

间断有限元离散纵标方法(Sn)是广泛应用于求解高维非定常中子输运方程的数值方法,它涉及几何网格空间、速度相空间和中子能群的离散,计算量很大．该文基于非结构网格,提出了基于区域分解的并行流水线Sn扫描算法,通过设计具有不同内在并行度和通信面体比的区域分解方法和队列插入算法,对两个不同物理模型,分别使用两台并行机的92个和256个CPU,获得72倍和78倍以上的加速．可扩展性能分析表明,算法的性能非常依赖于并行机的点对点通信延迟．     

High Order Fast Sweeping Methods for Static Hamilton–Jacobi Equations

We construct high order fast sweeping numerical methods for computing viscosity solutions of static Hamilton–Jacobi equations on rectangular grids. These methods combine high order weighted essentially non-oscillatory (WENO) approximations to derivatives, monotone numerical Hamiltonians and Gauss–Seidel iterations with alternating-direction sweepings. Based on well-developed first order sweeping methods, we design a novel approach to incorporate high order approximations to derivatives into numerical Hamiltonians such that the resulting numerical schemes are formally high order accurate and inherit the fast convergence from the alternating sweeping strategy. Extensive numerical examples verify efficiency, convergence and high order accuracy of the new methods.     

Prioritized Sweeping: Reinforcement Learning with Less Data and Less Time

We present a new algorithm,prioritized sweeping, for efficient prediction and control of stochastic Markov systems. Incremental learning methods such as temporal differencing and Q-learning have real-time performance. Classical methods are slower, but more accurate, because they make full use of the observations. Prioritized sweeping aims for the best of both worlds. It uses all previous experiences both to prioritize important dynamic programming sweeps and to guide the exploration of state-space. We compare prioritized sweeping with other reinforcement learning schemes for a number of different stochastic optimal control problems. It successfully solves large state-space real-time problems with which other methods have difficulty.     

振弦式传感器扫频激振技术

介绍一种基于ICL8038的扫频激振技术实现激振单线圈振弦式传感器的新方法，它与传统的激振方法相比，具有硬件电路简单、激振效果好、速度快、可控性好等优点。