基于物联网的活动范围受限人员监管系统的研究

首先介绍了活动范围受限人员监管系统的需求和研究意义,之后给出了系统的总体架构.在此基础上,着重介绍了基于RSSI(Received Signal Strength Indication)的测距原理和高斯模型校验方法,以及利用陀螺仪传感器通过航位推测算法进行方位计算的思想与方法.系列测试和实验结果表明,采用的RSSI测距方法和航位推算方法设计的系统可以有效的应用于活动范围受限人员的监管.     

上海天文台亚厘米级单次测距精度的卫星激光测距试验

2001年8月, 中国科学院上海天文台与捷克技术大学合作在上海天文台进行了亚厘米级单次测距精度的卫星激光测距试验. 采用皮秒事件计时器作为激光往返脉冲的时间间隔测量仪器, 配合原有的发射和接收系统, 对Lageos-1, 2, Starlette, Stella, Topex和ERS-2等卫星进行了测距试验. 分析表明: 对这些卫星的单次测距精度达到了7~8 mm. 为了对比, 原有的测距系统同时对这些卫星进行了测量, 单次测距精度为12~15 mm. 表明新测距系统的测量精度比原有系统提高了约80%. 同时还对原有测距系统的系统偏差进行了检测.     

一种测距定位仪的数学模型

将观测定距的一般性问题归结为对于已知平面矩形的测距问题.将实物成像的标示点屏幕坐标作为已知观测数据,给出了物距的简明计算方法.     

上海天文台第三代卫星激光测距系统

本文介绍了中国科学院上海天文台的第三代卫星激光测距系统的性能及三年来对LAGEOS,AJISAI和STARLETTE等卫星的实测结果.卫星轨道拟合和地面靶的测距试验均表明,本系统的卫星测距精度(均方差)约±5cm.     

伪随机序列

在数字通信、测距及跟踪系统中常用伪随机序列来调制信号(即将信号波形用此种序列编码),以达到提高可靠性和有效性或保密等目的.其重要的应用是在测距方面.据报导,早期曾用长度为2~(13)-1=8191的 m-序列于金星测距,在极低的信噪比情况下提取信号,达到极高的测量精度;但这是用长的积累时间换取到的.后来,为了能快速检测,有的深空测距系统用几个短 m-序列的 Boole 组合序列调制连续载波,从而大大缩减了积累时间.伪随机序列亦曾用于可由单人背负的便携式连续波 Doppler 雷达,供前沿侦察之用;在功率相当低的情况下,提供了清晰的距离与速度信息.本文将国外资料中有关伪随机序列的主要结果作一侧重于数学方法的介绍,主要参考资料列在后面.     

学好数学,上测星辰,下量物距

<正>对军事感兴趣的同学或许在电视或书刊上看过与图1类似的画面:士兵们右手平举于正前方,竖起大拇指,眯着一只眼,另一只眼作瞄准状态．士兵们是在为谁点赞吗?其实不是,士兵们是在测量自己与前方某目标的距离．这也太神奇了,不借助任何工具,只用手比划一下就能测距离了?其实,士兵们用的是跳眼法测距,下面我们就用所学的数学知识来揭秘跳眼法原理．     

雷达信息处理中的统计估值问题——连续波雷达载波信息的最佳利用

连续波雷达的高精度性能早期受测距起点精度影响很大,近期利用载波信息提高测距精度成为重要的研究课题之一,本文提出通过建立特定的统计估值模型,给出递推显式解,实现计算机联机实时输出的解决方法,它和用硬设备实现的近年来提出所谓载波辅助跟踪技术的出发点一样,对载波信息最佳利用,但无疑使设备复杂性大大降低。     

Q矩阵的结构与有限域上多项式的可约性

<正> 近年来,由移位寄存器所产生的序列在一些实际问题中得到了应用,例如数字通信中的纠错编码、测距等,因此种序列的伪随机性还可用于一些需要随机数的领域,如蒙特卡罗方法等.     

卫星激光测距中激光脉冲波形变化的理论分析及数值计算

分析了激光测距中脉冲波形变化的物理过程,给出了该变化的数学描述,讨论了脉冲波形变化对卫星质心改正(CoM)和测距精度(RMS)的影响,并对上述变化和影响进行了数值计算.计算结果揭示了激光脉冲波形在各种因素影响下产生变化的规律性,这对于毫米级精度的卫星激光测距系统的设计具有实际意义.     

白天卫星激光测距系统的设计和实测结果

中国科学院上海天文台首次建立了一套白天卫星激光测距系统 .分析了白天强烈噪声的虚警概率和白天探测单光子激光回波的成功概率 ,详述了该系统的总体设计、性能参数、研制过程、采用的关键技术和卫星实测的结果 .     

Cost‐efficient monitoring of continuous‐time stochastic processes based on discrete observations

Planning a cost‐efficient monitoring policy of stochastic processes arises from many industrial problems. We formulate a simple discrete‐time monitoring problem of continuous‐time stochastic processes with its applications to several industrial problems. A key in our model is a doubling trick of the variables, with which we can construct an algorithm to solve the problem. The cost‐efficient monitoring policy balancing between the observation cost and information loss is governed by an optimality equation of a fixed point type, which is solvable with an iterative algorithm based on the Feynman‐Kac formula. This is a new linkage between monitoring problems and mathematical sciences. We show regularity results of the optimization problem and present a numerical algorithm for its approximation. A problem having model ambiguity is presented as well. The presented model is applied to problems of environment, ecology, and energy, having qualitatively different target stochastic processes with each other.     

基于QAR数据的民航客机对称发动机差异监控模型和算法

从某型民航客机发动机机队管理的实际出发,利用HOLT双参数指数平滑方法,建立基于机载QAR数据的对称发动机性能参数的差异监控模型,并给出实现对称发动机差异监控的算法。算例分析表明模型和算法能有效地识别发动机运行状态,并能预测发动机故障征兆,使发动机排故端口提前,且方法简单易于实现。     

云计算环境资源监控系统研究

为保障云计算平台的可靠性,基于Ganglia,采用Eucalyptus开源云平台,提出了云计算平台资源监控系统架构.从总体结构、监控信息处理流程等多个方面对监控系统进行了详细阐述,提出了动态更换虚拟机簇头的算法,并对算法与原型系统进行了验证和性能评测.分析与评测结果表明,所提系统能够适用于云计算环境资源信息的实时监测与预警,具备系统开销较低,用户接口友好的特点,能准确反映系统、虚拟机的负载信息,有助于云计算系统服务可靠性的提升.簇头动态更换算法能及时发现失效的簇头并更换为更健壮的虚拟机,保证了监测系统的正常运行.     

基于奇异值分解和K means算法的近海水质数据分类方法

以辽东湾某生态监测区水质监测数据为例,以矩阵的奇异值分解和K means算法为分类工具,给出生态监测区水质监测数据的分类方法.方法具有以下特点:通过奇异值分解简化并加速了类比过程,通过动态设置类K避免了K means算法先设定类数的不足,还探讨了对少量新增监测数据的归类问题.方法对近海海水水质监测数据分类具有普适性.     

Multiple UAVs path planning algorithms: a comparative study

Unmanned aerial vehicles (UAVs) are used in team for detecting targets and keeping them in its sensor range. There are various algorithms available for searching and monitoring targets. The complexity of the search algorithm increases if the number of nodes is increased. This paper focuses on multi UAVs path planning and Path Finding algorithms. Number of Path Finding and Search algorithms was applied to various environments, and their performance compared. The number of searches and also the computation time increases as the number of nodes increases. The various algorithms studied are Dijkstra’s algorithm, Bellman Ford’s algorithm, Floyd-Warshall’s algorithm and the AStar algorithm. These search algorithms were compared. The results show that the AStar algorithm performed better than the other search algorithms. These path finding algorithms were compared so that a path for communication can be established and monitored.     

Automatic detection and identification of shocks in Gaussian state‐space models: a Bayesian approach

An automatic monitoring and intervention algorithm that permits the supervision of very general aspects in an univariate linear Gaussian state–space model is proposed. The algorithm makes use of a model comparison and selection approach within a Bayesian framework. In addition, this algorithm incorporates the possibility of eliminating earlier interventions when subsequent evidence against them comes to light. Finally, the procedure is illustrated with two empirical examples taken from the literature. Copyright © 2005 John Wiley & Sons, Ltd.     

Joint Monitoring of Several Types of Shocks in Normal Dynamic Linear Models: A Bayesian Decision Theoretic Approach

In this article we consider the sequential monitoring process in normal dynamic linear models as a Bayesian sequential decision problem. We use this approach to build a general procedure that jointly analyzes the existence of outliers, level changes, variance changes, and the development of local correlations. In addition, we study the frequentist performance of this procedure and compare it with the monitoring algorithm proposed in an earlier article.     

Optimal sensor placement for modal identification of structures using genetic algorithms—a case study: the olympic stadium in Cali,Colombia

Adequate sensor placement plays a key role in such fields as system identification, structural control, damage detection and structural health monitoring of flexible structures. In recent years, interest has increased in the development of methods for determining an arrangement of sensors suitable for characterizing the dynamic behavior of a given structure. This paper describes the implementation of genetic algorithms as a strategy for optimal placement of a predefined number of sensors. The method is based on the maximization of a fitness function that evaluates sensor positions in terms of natural frequency identification effectiveness and mode shape independence under various occupation and excitation scenarios using a custom genetic algorithm. A finite element model of the stadium was used to evaluate modal parameters used in the fitness function, and to simulate different occupation and excitation scenarios. The results obtained with the genetic algorithm strategy are compared with those obtained from applying the Effective Independence and Modal Kinetic Energy sensor placement techniques. The sensor distribution obtained from the proposed strategy will be used in a structural health monitoring system to be installed in the stadium.     

基于改进PSO-BP神经网络的贮存可靠性预测

贮存可靠性是军事储备质量监测的重要环节,科学准确地预测贮存可靠度是现代化军事评估的必然要求。针对历史贮存数据,建立可靠度与年限的贮存可靠性预测模型,采用进化策略改进粒子群算法(PSO)优化BP神经网络进行贮存可靠性预测。通过数据扩充提高样本质量和数量,应用改进后的PSO算法优化BP神经网络的初始权值和阈值,提高网络的泛化能力。PSO算法较好的全局搜索能力与BP网络很强的局部搜索能力相结合,能够避免早熟现象,提高算法的收敛速度及预测精度。实验结果表明,改进的PSO-BP网络模型比PSO-BP和BP神经网络获得更好的预测性能。