Error log analysis: statistical modeling and heuristic trendanalysis

Most error-log analysis studies perform a statistical fit to the data assuming a single underlying error process. The authors present the results of an analysis that demonstrates that the log is composed of at least two error processes: transient and intermittent. The mixing of data from multiple processes requires many more events to verify a hypotheses using traditional statistical analysis. Based on the shape of the interarrival time function of the intermittent errors observed from actual error logs, a failure-prediction heuristic, the dispersion frame technique (DFT), is developed. The DFT was implemented in a distributed system for the campus-wide Andrew file system at Carnegie Mellon University. Data collected from 13 file servers over a 22-month period were analyzed using both the DFT and conventional statistical methods. It is shown that the DFT can extract intermittent errors from the error log and uses only one fifth of the error-log entry points required by statistical methods for failure prediction. The DFT achieved a 93.7% success rate in predicting failures in both electromechanical and electronic devices     

Error analysis of the moment method

Because of the widespread use of the Method of Moments for simulation of radiation and scattering problems, analysis and control of solution error is a significant concern in computational electromagnetics. The physical problem to be solved, its mesh representation, and the numerical method all impact accuracy. Although empirical approaches such as benchmarking are used almost exclusively in practice for code validation and accuracy assessment, a number of significant theoretical results have been obtained in recent years, including proofs of convergence and solution-error estimates. This work reviews fundamental concepts such as types of error measures, properties of the problem and numerical method that affect error, the optimality principle, and basic approximation error estimates. Analyses are given for surface-current and scattering-amplitude errors for several scatterers, including the effects of edge and corner singularities and quadrature error. We also review results on ill-conditioning due to resonance effects and the convergence rates of iterative linear-system solutions.     

Error probability estimator structures based on analysis of thereceiver decision variable

The paper presents schemes for rapid on-line error probability estimation of digital communications links. Several estimator structures are proposed based on the assumption of sample independence, including weighted least squares (WLS) and maximum likelihood (ML) forms. The continuous-form ML estimator is shown to lie on the Rao-Cramer bound, making it a most efficient estimator of probability of error. The design, performance, implementation complexity and behavior of these estimators is described for AWGN     

Error performance analysis for narrow-band duobinary FM withdiscriminator detection and soft decision decoding

An analytical method for calculating error rates for duobinary FM systems with discriminator detection and Viterbi sequence estimation decoding is presented. Gaussian noise and intersymbol interference are included in the channel model, and high signal-to-noise ratio and precoding of the binary input message are assumed in the analysis. The computed error rates are compared to previously published measurements. The agreement is very good, confirming that the assumptions are valid and useful     

一种基于统计分析的解定位模糊方法

针对相位测量定位系统是否正确解辐射源位置模糊的判别问题,提出了基于相位差拟合误差均值与方差假设检验的统计判断方法,以逐步剔除错误解;对于剩余的正确辐射源位置估计,给出了提高定位精度的统计处理方法和辐射源位置估计的置信椭圆.仿真试验结果表明,提出的解模糊方法能有效降低将错误解判别为正确解的误判比例,定位结果的统计处理方法可以提升定位精度并缩小置信椭圆.所提方法对于促进相位干涉仪系统的实际应用具有积极意义.     

Extension of the moment-analysis method for statistical analysis to include linear-correlation effects

A technique for extending the moment-analysis method for statistical analysis to include linear-correlation effects is presented. This technique has the advantage of being significantly faster than previous methods for treating linear-correlation effects. Included is an example of the effect of linear correlation between load and driver devices on the probability-density function of the output voltage of an m.o.s.t. integrated invertor.     

Social decision analysis

How can a diverse free society find decision mechanisms that are logical, efficient, and timely? This is a problem that has challenged man at least from the time of Plato's Republic. We see today factions of society arguing over alternatives rather than over values or probabilities. Adversary proceedings encourage people to advocate extremes rather than a careful balance of several considerations. Decision analysis, a logical procedure for balancing the many uncertain, complex, and dynamic factors that characterize a decision, offers promise of a new and valuable procedure for social decisions. The decision analyst creates an extrapersonal explicit model of the decision under consideration. Information on possible alternatives, uncertainties, relationships, or preferences can come from different groups and still be represented within the same decision model, with the implications for the decision apparent to all. One can imagine a society where decision making has become decentralized, where distinct bodies are responsible for creating social alternatives, assessing the probabilities of various outcomes for each alternative, and setting the preferences of society. Once the alternatives, information, and preferences were established, society would make the decision using only the principles of logic. Applications to automotive pollution, hurricane seeding, and nuclear safety demonstrate the approach.     

基于统计自然语言分析的九宫格输入法最优键盘布局

九宫格输入法是手机端常用的中文输入法之一,可将26个英文字母按顺序布局在8个数字键上,每个键上有3～4个字母.然而顺序布局显然不是最优的.本文采用统计自然语言处理计算键盘布局的平均击键次数,并采用模拟退火算法优化,在搜寻键盘数据时,对其实行哈希计算,避免重复搜索,最终找到九宫格输入法的最优键盘布局方案.结果显示,本文的最优键盘布局方案比顺序布局的输入效率明显提升,可以提高生活的便利程度和工作效率.     

基于统计的高效决策树分组分类算法

基于决策树的分组分类算法因易于实现和高效性,在快速分组分类中广泛使用。决策树算法的基本目标是构造一棵存储高效且查找时间复杂度低的决策树。设计了一种基于规则集统计特性和评价指标的决策树算法——HyperEC 算法。HyperEC算法避免了在构建决策树过程中决策树高度过高和存储空间膨胀的问题。HyperEC算法对IP地址长度不敏感,同样适用于IPv6的多维分组分类。实验证明,HyperEC算法当规则数量较少时,与HyperCuts基本相同,但随着规则数量的增加,该算法在决策树高度、存储空间占用和查找性能方面都明显优于经典的决策树算法。     

基于多尺度决策融合的SAR图像溢油检测方法分析

本文以墨西哥湾溢油事故的一幅SAR溢油影像数据为信息源,通过多尺度分析和基于灰度共生矩阵的纹理特征提取,最后引入多尺度决策融合策略,对各尺度获得的检测结果进行融合,从而形成统一的溢油检测框架。     

基于C++的常微分方程欧拉解法的误差分析

工程计算中常微分方程的欧拉解法存在一定的误差，而实际往往要求其满足一定的精度。以工程中的一个常微分方程为例，运用C＋＋程序对其欧拉解法的误差进行分析。     

用空间解析几何法进行天文定位定向的误差分析

为了确定三视场定位定向设备各个误差源对定位定向误差的影响,建立了定位定向的误差分析模型。首先,给出了三视场导航设备采用空间解析几何法进行定位定向的原理。其次,指出影响定位定向的各个误差源,归纳分析了误差源的特性、概率分布以及误差源对定位定向信息对的影响。然后,利用定位定向原理建立起定位定向误差分析模型。最后,利用蒙特卡罗法进行误差仿真分析。仿真结果表明系统的定位均值误差为121.0 m;定向均值误差为7.4,并指出定位定向主要的误差源是水平测量误差,其次是垂线偏差数据的误差。野外实验表明,该系统的定位均值误差为182.12 m;定向均值误差为9.3,水平测倾角的误差对定位定向结果的影响最大。     

BER analysis of a GMSK system using decision feedback

There are considerable literatures on the Bit Error Rate（BER）evaluation of Differential Detection of Gaussian Minimum Shift Keying（DDGMSK）system using Decision Feedback（DF）,but most of them give the performance based on the Monte Carlo Error Counting（MCEC）technique.From the probability distribution of the phase angle between two vectors perturbed by Gaussian noises,the formulae of BER are derived for the performance analysis of DDGMSK system with DF in this letter.Considering the m-bit dock-tailed sequence,the new formulae of Gaussian Minimum Shift Keying（GMSK）modulated phase and the Time-Varying Signal to Noise Ratio（TVSNR）of the demodulated signal are presented,and it is proved that the relationship between the TVSNR of the demodulated signal and the size of eye opening is not inevitable.Simulation results show that the theoretical investigation gives analogous results with the MCEC technique.The formulae presented are useful for the performance analysis of systems using GMSK as modulating and demodulating method,for instance,the analysis of synchronous performance of frequency-hopping communication system.     

国家电网客服工单投诉统计分析方法研究

文章形成了一种数据统计分析机制,通过多维度分析客户诉求,实现了从海量数据信息中将有价值的数据集中、萃取和提炼,全面、深入、系统的分析供电管理中95598工单投诉初步存在问题,反映业务实际情况和工单管理状况,有效降低客户投诉风险。     

Efficient statistical circuit analysis

The letter reports the results of a preliminary feasibility study of an efficient method of statistical analysis for linear nonreciprocal circuits.     

NGN网络测试仪表实时统计方案的设计与应用

本文介绍了NGN网络测试仪表中一种支持用户自定义时段统计结果查看的统计方案设计与应用,实现用户自由输入任一时间段,查看该时段网络的通信状况,极大地方便了用户对通信网络的运管维护。本文对统计的粒度、文件、模块进行了分析、设计,并在此基础上提出了统计与统计结果获取的实现方式,以INAP协议监测为例阐述了该方案在NGN测试仪中的具体应用,从该实例中证明了设计的合理性和可行性。本文涉及的统计方案在其他网络测试仪表的研发中具有通用的指导和推广意义。     

Imaging below the diffraction limit: a statistical analysis

The present paper is concerned with the statistical analysis of the resolution limit in a so-called "diffraction-limited" imaging system. The canonical case study is that of incoherent imaging of two closely-spaced sources of possibly unequal brightness. The objective is to study how far beyond the classical Rayleigh limit of resolution one can reach at a given signal to noise ratio. The analysis uses tools from statistical detection and estimation theory. Specifically, we will derive explicit relationships between the minimum detectable distance between two closely-spaced point sources imaged incoherently at a given SNR. For completeness, asymptotic performance analysis for the estimation of the unknown parameters is carried out using the Cramér-Rao bound. To gain maximum intuition, the analysis is carried out in one dimension, but can be well extended to the two-dimensional case and to more practical models.     

Design and statistical analysis of a hash-aided image watermarking system

This paper develops a joint hashing/watermarking scheme in which a short hash of the host signal is available to a detector. Potential applications include content tracking on public networks and forensic identification. The host data into which the watermark is embedded are selected from a secret subset of the full-frame discrete cosine transform of an image, and the watermark is inserted through multiplicative embedding. The hash is a binary version of selected original image coefficients. We propose a maximum likelihood watermark detector based on a statistical image model. The availability of a hash as side information to the detector modifies the posterior distribution of the marked coefficients. We derive Chernoff bounds on the receiver operating characteristic performance of the detector. We show that host-signal interference can be rejected if the hash function is suitably designed. The relative difficulty of an eavesdropper's detection problem is also determined; the eavesdropper does not know the secret key used. Monte Carlo simulations are performed using photographic test images. Finally, various attacks on the watermarked image are introduced to study the robustness of the derived detectors. The joint hashing/watermarking scheme outperforms the traditional "hashless" watermarking technique.     

基于决策树的企业信息系统故障自动诊断分析方法

目前,大型企业信息系统规模和复杂度快速增长,但对故障的诊断分析仍主要依赖传统的人工经验,这不仅耗时、耗力,还影响对故障的及时处理.针对这一问题,创新性地提出了基于决策树的企业信息系统故障自动诊断分析方法,根据信息系统运行监控指标告警信息,实现对信息系统故障的自动诊断.利用某大型国有企业的实际生产运行数据,提取典型告警数据特征对该方法进行了验证,并在R语言环境下对决策树模型及其训练方法进行了仿真和对比分析.实验结果证明,该方法可以较为准确地实现故障自动快速诊断,有助于提高信息系统故障诊断分析效率.     

DWDM窄带滤光片膜层的误差分析与监控策略

为了提高密集波分复用(DWDM)薄膜窄带滤光片制备的成品率,讨论了用于DWDM薄膜窄带滤光片在镀制过程中的监控方法及误差,采用Monte Carlo允差分析原理分析用于DWDM窄带滤光片膜层的容差,以便选择更易制备的膜系;计算膜层的Mac leod极值灵敏度,得到所选膜系各个膜层的误差要求;模拟光学监控过程和计算膜层导纳,能够得到膜层制备过程中膜层之间膜厚的补偿关系。实验表明,据此制定的膜厚监控策略,对于DWDM窄带滤光片膜层的制备和保证成品率是非常关键的。