Practical security of continuous-variable quantum key distribution under finite-dimensional effect of multi-dimensional reconciliation

The well-known multi-dimensional reconciliation is an effective method used in the continuous-variable quantum key distribution in the long-distance and the low signal-to-noise-ratio scenarios.The virtual channel employed to exchange data is generally established by using a finite-dimensional rotation in the reconciliation procedure.In this paper,we found that the finite dimension of the multi-dimensional reconciliation inevitably leads to the mismatch of the signal-to-noise-ratio between the quantum channel and the virtual channel,which may be called the finite-dimension effect.Such an effect results in an overestimation on the secret key rate,and subsequently induces vital practical security loopholes.

Research on the Development and Optimization of Financial Management and Benefit Distribution Pattern from the Perspective of Multi-Dimensional Cooperation Enterprise

In this paper, we conduct analysis on the development and optimization of financial management and the benefit distribution pattern from perspective of multi-dimensional cooperation enterprise. Financial management is the whole process of capital operation of the modern enterprise decision-making, planning and control of the management activities. Financial management is an important part of enterprise management, enterprise＇ s sustainable development requires the financial management in the central position in the management of the enterprise, according to the present our country enterprise financial management of a series of problems, in this paper, starting from the connotation of the enterprise financial management, we analyses the center of the enterprise financial management status and further puts forward some countermeasures to solve from the perspectives of the multi-dimensional cooperation which obtains the satisfactory performance.

Stability Analysis of Multi-Dimensional Linear Discrete System and Root Distribution Using Sign Criterion with Real Coefficients

A new idea was proposed to find out the stability and root location of multi-dimensional linear time invariant discrete system (LTIDS) for real coefficient polynomials. For determining stability the sign criterion is synthesized from the Jury’s method for stability which is derived from the characteristic polynomial coefficients of the discrete system. The number of roots lying inside or outside the unit circle and hence on the unit circle is directly determined from the proposed single modified Jury tabulation and the sign criterion. The proposed scheme is simple and the examples are given to bring out the merits of the proposed scheme which is also applicable for the singular and non-singular cases.

MULTI-DIMENSIONAL MARKOV CHAIN–BASED ANALYSIS OF CONFLICT PROBABILITY FOR SPECTRUM RESOURCE SHARING

In this paper, we consider the optimal problem of channels sharing with het-erogeneous traffic （real-time service and non-real-time service） to reduce the data conflict probability of users. Moreover, a multi-dimensional Markov chain model is developed to analyze the performance of the proposed scheme. Meanwhile, performance metrics are derived. Numerical results show that the proposed scheme can effectively reduce the forced termination probability, blocking probability and spectrum utilization.

平衡损失下Possion分布参数的估计

设X1,…,Xn是Possion分布总体P的样本,其中是未知参数.在平衡损失函数下,取共轭先验时,得到了的Bayes估计,进而讨论了的形如aX+b的估计的容许性问题.

居民伤害发生相关因素的Possion分布多水平模型分析

目的:探讨个人和家庭常见伤害的影响因素,为进一步开展居民伤害预防提供科学依据。方法:采用整群抽样的方法对浙江省11个地区的3639户常住居民家庭,共计11761个居民进行与伤害相关的问卷调查。单因素分析采用2检验或Wilcoxon符号秩和检验;伤害发生的影响因素采用Possion分布多水平模型的方法。结果:浙江居民伤害的发生率为8.83%。男性伤害发生率高于女性。各伤害类型数量排序由高到低依次为交通事故、跌落、钝器伤和烧烫伤等。多水平模型结果显示代表家庭差异的估计值为1.36,且有统计学意义;女性居民伤害的发生较男性的风险低;体力劳动者较脑力劳动者易发生伤害;每天吸烟20支及以上者较不吸烟者易发生伤害。结论:浙江居民伤害发生的变异在家庭方面存在聚集性;居民伤害发生的相关因素主要为性别、工作性质和吸烟。

An Efficient Algorithm for Distributed Outlier Detection in Large Multi-Dimensional Datasets

The distance-based outlier is a widely used definition of outlier. A point is distinguished as an outlier on the basis of the distances to its nearest neighbors. In this paper, to solve the problem of outlier computing in distributed environments, DBOZ, a distributed algorithm for distance-based outlier detection using Z-curve hierarchical tree （ZH-tree） is proposed. First, we propose a new index, ZH-tree, to effectively manage the data in a distributed environment. ZH-tree has two desirable advantages, including clustering property to help search the neighbors of a point, and hierarchical structure to support space pruning. We also design a bottom-up approach to build ZH-tree in parallel, whose time complexity is linear to the number of dimensions and the size of dataset. Second, DBOZ is proposed to compute outliers in distributed environments. It consists of two stages. 1） To avoid calculating the exact nearest neighbors of all the points, we design a greedy method and a new ZH-tree based k-nearest neighbor searching algorithm （ZHkNN for short） to obtain a threshold LW. 2） We propose a filter-and-refine approach, which first filters out the unpromising points using LW, and then outputs the final outliers through refining the remaining points. At last, the efficiency and the effectiveness of ZH-tree and DBOZ are testified through a series of experiments.

基于概率分布模型的北京地区冰雹灾害风险区划

利用北京地区20个地面气象台站1951—2006年的冰雹数据,统计分析了各台站冰雹日数在作物生长季4-10月的不同月份及年度发生的风险概率特征,并在此基础上进行了北京地区不同时段不同雹日数的冰雹风险区划。结果表明:北京地区各台站雹日数在不同时段的发生具有明显的POSSION分布特点;从年度分布来看,风险概率随着年雹日的增多逐渐降低,各台站年雹日≥1、2、3、4 d的风险概率分别在50%、18.8%、4.6%和0.9%以上。从空间来看,北京地区冰雹风险具有明显的山区高于城区的空间分布特征,山区又以西北部最大、东部和西部次之、南部最小;西北部山区佛爷顶附近冰雹年发生概率高达98.1%,6月冰雹风险概率也在60%以上,是北京地区冰雹的主灾区。

基于CSMA/CD协议的以太网络性能仿真技术研究

根据以太网络的随机访问方式和到达帧的突发特性 ,证明了以太网络的帧到达过程服从泊松分布 ,提出了以太网络系统的排队模型 ,并对基于 CSMA/ CD协议的以太网络系统性能进行了仿真 。

最可能数的精确计算及其在食品微生物检验中的应用

目的最可能数(MPN)方法已经被广泛应用于多种食品安全指标菌的检测中,但是由于大多数操作者对该方法的原理及使用原则缺乏了解,错误地使用了该方法,最终导致对结果的错误评价。本文通过解决上述问题来增强该方法的可操作性。方法利用细菌浓度泊松分布数学模型全面分析MPN值及其置信区间;通过国内外相关标准方法的比较分析,以相应实例诠释MPN表的实际应用原则。结果推导MPN置信区间的精确计算公式;通过ISO标准的概率类群分类的引入建立新的MPN表;扩展FDA标准中5个平行样品连续稀释度的选取原则至9管法,建立实例表。结论 MPN值的置信区间可以通过数学模型进行精确的计算,计算结果将为国内外标准方法的进一步修定提供很好的参考;MPN方法的关键是将样品进行倍比稀释直至产生阴性管,MPN值的确定取决于对实验结果中连续稀释度的正确选择。

股票价格服从跳-扩散过程的期权定价模型

研究了股票价格的行为模型问题.假定股票价格的跳过程为一类特殊的更新过程,建立了股票价格服从跳 扩散过程的行为模型.在风险中性的假设下,推导出了基于股票的欧式期权定价公式.

Ka频段移动卫星星地链路误码统计分析

针对Ka频段移动卫星星地链路的特性,全面考虑天气和移动终端周边环境的影响,建立了Ka频段移动卫星星地信道模型。对二进制相移键控(BPSK)调制方式下的星地信道进行仿真和数字基带误码图案的统计分析,并采用最小二乘法对误码发生次数的概率进行了拟合。研究表明:信道误码发生次数服从泊松分布,在Ka频段移动卫星星地信道的数字基带模拟中,BPSK调制方式下的系统误码由突发误码和服从泊松分布的随机误码组成。

复合泊松分布参数估计的EM算法

复合泊松分布是非寿险精算中的重要理赔模型,利用正规的统计方法(如极大似然估计)估计模型的参数往往比较困难,而矩估计的精度在大样本下才能有令人满意的结果.本文应用EM算法研究了复合泊松分布的参数估计问题,给出了参数满足的方程,并给出了参数的矩估结果,对两种参数估计结果,通过计算机模拟,表明EM算法对参数的估计更为有效,且EM算法在小样本下就能得到较好的估计效果.

一阶随机系数整值滑动过程

建立了特殊的一阶随机系数整值滑动平均模型.研究发现:固定指标t,该过程服从泊松分布;求得该过程的期望、方差、协方差;证明了该过程是宽平稳过程,均值具有遍历性;得到了模型参数的区间估计与具有一致性与无偏性的矩法估计,并对估计量的效果进行了模拟研究.

工业以太网时延分析与建模研究

介绍工业控制网络最近的发展状况,在此基础上讨论工业以太网的实时性及以往相关研究的不足,进而提出截尾泊松分布并将其应用于工业以太网时延分析中,推导出对将来进一步研究有重要意义的公式并给出时延分析模型.

浅谈二项分布的近似计算

讨论了用Possion定理、局部极限定理和积分极限定理近似计算二项分布概率时的误差,对这3种近似计算的误差进行了比较,详细分析了用局部极限定理做近似计算时的误差。

一种放射CT重建的鲁棒估计算法

放射CT的重建问题可以归结为一种基于泊松分布的最大似然估计（MuxnimumLikelihood,ML），其中最著名的如EM算法[1]，这种算法存在的问题是鲁棒性不强，当观测数据中存在一些出格点（outlier）（如2％）时，EM算法的性能就变得很差。本文分析了算法性能变差的原因，将泊松分布近似为高斯分布后，仿照鲁律估计中的M-估计，构造了一种鲁棒性很强的EM改进算法。实验结果表明，即使在投影数据中混有10％的出格点，仍能重建出满意的结果来。

脉冲干扰下的星间扩频码域并行捕获性能研究

星间链路的高动态给星间扩频信号带来高达几百kHz的多普勒频偏,本文提出一种利用卫星历书进行多普勒预估计与码域并行捕获相结合实现星间扩频信号捕获的算法。同时,常规的高斯白噪声下捕获概率分析对空间电磁脉冲不具有针对性,本文利用Possion分布对空间电磁脉冲干扰进行建模,对该并行捕获的捕获概率、捕获时间的影响进行了研究,表明该算法在信干比为-7.4dB时,捕获概率仍在90%以上,适于星间扩频信号的捕获。

常见概率分布之间的关系

概率分布是概率论研究的基础,本文通过分析常见分布的概率背景,得到了常见分布之间的内在联系。

基于泊松分布的光子计数激光雷达点云去噪

针对光子计数激光雷达数据特点,研究基于泊松分布的点云去噪算法并开展精度评估。首先,将点云投影到二维剖面,划分格网并统计每个格网光子点个数,剔除点数大于平均值部分以计算背景噪声率;随后,从小到大调整格网尺寸,统计各尺寸下格网内的点数,大于阈值时将该网格内的点都标记为信号,并且根据比例大小划分为高、中、低置信度三类;最后,采用分段直线拟合将倾斜点投影到直线上以识别倾斜地形,采用分段二次拟合方法剔除残余孤立噪点,得到优化结果。利用多组不同地形光子点云数据开展实验,结果表明:基于泊松分布的去噪算法在冰盖、海洋场景下效果较好,整体精度优于96%,在植被场景稍差,但能达到识别信号的基本目标。