An upper bound estimate on classification error (Corresp.)

An upper bound estimate on the Bayes misclassification error is derived using a kernel function to estimate probability density functions. As a result of this bound, a relationship between a Euclidean distance and a probability of misclassification is indicated.     

Interpolatory quadrature rules and error rate of digital communication systems

A simple numerical technique is proposed for the construction of the estimate of integrals which represent the average error probability of many digital communication systems. Since these integrals are expressed as the expectation of some function of a random variable, their evaluation can be based on the knowledge of a number of moments of the variable. This is investigated from the viewpoint of discussing an algorithm based on interpolatory quadrature formulas which have equally spaced nodes. An example shows the satisfactory performance of the proposed approach.     

On outage and error rate analysis of the ordered V-BLAST

Outage and error rate performance of the ordered BLAST with more than 2 transmit antennas is evaluated for i.i.d. Rayleigh fading channels. A number of lower and upper bounds on the 1st step outage probability at any SNR are derived, which are further used to obtain accurate approximations to average block and total error rates. For m Tx antennas, the effect of the optimal ordering at the first step is an m-fold SNR gain. As m increases to infinity, the BLER decreases to zero, which is a manifestation of the space-time autocoding effect in the V-BLAST. While the sub-optimal ordering (based on the before-projection SNR) suffers a few dB SNR penalty compared to the optimal one, it has a lower computational complexity and a 3 dB SNR gain compared to the unordered V-BLAST and can be an attractive solution for low-complexity/low-energy systems. Uncoded D-BLAST exhibits the same outage and error rate performance as that of the V-BLAST. An SNR penalty of the linear receiver interfaces compared to the BLAST is also analytically evaluated.     

A software solution to estimate the SEU-induced soft error rate for systems implemented on SRAM-based FPGAs

SRAM-based FPGAs are very susceptible to radiation-induced Single-Event Upsets(SEUs) in space applications.The failure mechanism in FPGA’s configuration memory differs from those in traditional memory device.As a result,there is a growing demand for methodologies which could quantitatively evaluate the impact of this effect.Fault injection appears to meet such requirement.In this paper,we propose a new methodology to analyze the soft errors in SRAM-based FPGAs.This method is based on in depth understanding of the device architecture and failure mechanisms induced by configuration upsets.The developed programs read in the placed and routed netlist,search for critical logic nodes and paths that may destroy the circuit topological structure,and then query a database storing the decoded relationship of the configurable resources and corresponding control bit to get the sensitive bits.Accelerator irradiation test and fault injection experiments were carried out to validate this approach.     

一种静态随机存储器型现场可编程门阵列的单粒子软错误率的软件分析方法

静态随机存取存储器(SRAM)型现场可编程门阵列(FPGA)在当前空间电子设备中取得了广泛的应用,尽管它对空间辐射引起的单粒子翻转效应极其敏感。在FPGA的配置存储器中发生的单粒子翻转造成的失效机理不同于传统的存储器中的单粒子翻转。因此,如何评价这些单粒子翻转对系统造成的影响就成了一个值得研究的问题。传统的方法主要分为辐照实验和故障注入两种技术途径。本文中提出了一种新的方法,可以用来分析单粒子翻转对构建在FPGA上的系统造成的影响。这种方法基于对FPGA底层结构以及单粒子翻转带来的失效机理的深入理解,从布局布线之后的网表文件出发,寻找所有可能破坏电路结构的关键逻辑节点和路径。然后通过查询可配置资源与相应的配置数据之间关系来确定所有敏感的配置位。我们用加速器辐照实验和传统的故障注入方法验证了这种新方法的有效性。     

On the rate of convergence of nearest neighbor rules (Corresp.)

An erroneous method for maximizing the projected divergence between two Gaussian multivariate hypotheses appeared in a recent paper. The correct solution is given.     

On the bit error rate of lightwave systems with optical amplifiers

The problem of evaluating the performances of communication systems with optical amplifiers and a wideband optical filter is addressed. Exact probability of error expressions for optical signals in presence of amplifier spontaneous noise and photodetector shot noise are given and compared with those predicted by Gaussian approximations for amplitude shift keying (ASK), frequency shift keying (FSK), or differential phase shift keying (DPSK) modulations, both for ideal photodetectors and for the case where shot noise is significant     

Software error rate evaluation

An expression for estimating the error rate of computer programs is suggested. It is assumed that the total number of errors in a computer program is proportional to the total number of instructions in the program and errors detected are proportional to remaining errors.     

最佳接收机误码率的两种估算观点

很多教材都是从统计的观点讨论分析了最佳接收机的误码率问题,统计的观点认为信道的噪声是非带限的高斯白噪声,分析的过程也假设接收机非带限。但是从实际和滤波的观点来看,任何形式的接收机都是频带受限的,进入到接收机检测器的噪声频带也会受限。文中基于统计和滤波的观点,讨论了最佳接收机的误码率问题,得出的结论相同,但是分析的过程体现了两者的不同之处,有助于更好的了解数字信号的最佳接收。     

Distribution-free performance bounds with the resubstitution error estimate (Corresp.)

Probability inequalities are given for the deviation of the resubstitution error estimate from the unknown conditional probability of error. The inequalities are distribution free and can be applied to linear discrimination rules, to nearest neighbor rules with a reduced sample size, and to histogram rules.     

ASP程序错误及处理

介绍了ASP程序中常见的三种错误类型,提出了有效防止错误的两个方面及错误处理的三种方法。     

应用支持向量回归估计预测陀螺误差系数

针对目前小样本容量陀螺误差系数预测精度不高的问题,本文将支持向量回归估计引入到陀螺误差系数的预测研究中。通过对某型陀螺某项误差系数的预测,并且对比分析该方法与目前通用的AR模型预测方法的预测效果,结果表明本文采用的支持向量回归估计具有更高的预测精度。     

An estimate of the error caused by the plane-wave approximation infree-space dielectric measurement systems

In a free-space measurement system, the electrical constitutive parameters of a plane sheet of material are determined using incident, transmitted and reflected electromagnetic beams. The electrical parameters are almost always obtained from the measured transmission and reflection coefficients using a procedure that approximates each beam as a single plane wave whose wavefront is parallel to the surfaces of the sheet (the plane-wave approximation). A theoretical model is constructed to investigate, in a very general way, the limitations of the plane-wave approximation. The field of the incident beam is taken to be a Gaussian function at the center of the sheet and analytic expressions are obtained for the transmitted and reflected beams using the plane-wave spectrum technique. Power transmission and reflection coefficients are calculated and series expansions of these coefficients are used to determine under what conditions the plane-wave approximation applies. Graphical results are presented to show how the error associated with the plane-wave approximation depends on the various parameters for the problem: electrical size of the beam waist, electrical thickness of the sheet etc     

Sampling theorem for wavelet subspaces: error estimate andirregular sampling

The error estimate is useful in the application of the sampling theorem. For the classical Shannon sampling theorem, various errors are widely studied, but for the sampling theorem in general wavelet subspaces, only the aliasing error is studied. In this paper, we study three other errors: truncation error, amplitude error, and time-jitter error. With the same technique, a result on irregular sampling is improved     

The angle error estimate method in the wide swath SAR basing on multi-receiver

The wide-swath method based on multi-receiver is a novel and highly accurate wide-swath method, which requires a very precise view angle. The estimated angle has error because of the atmosphere refraction, angle error of view and target height. A method is proposed in this paper to estimate the angle error from the return signal. The method makes use of the relationship between the view angle error and the signal correlation of the subswaths to estimate the angle error. The precision of this method is analyzed by the law of great number and it turns out to be in direct proportion to the root square number of averaging. The simulation result is given and the angle precision is 0.025°.     

A constraint-based genetic algorithm approach for mining classification rules

Data mining is an information extraction process that aims to discover valuable knowledge in databases. Existing genetic algorithms (GAs) designed for rule induction evaluates the rules as a whole via a fitness function. Major drawbacks of GAs for rule induction include computation inefficiency, accuracy and rule expressiveness. In this paper, we propose a constraint-based genetic algorithm (CBGA) approach to reveal more accurate and significant classification rules. This approach allows constraints to be specified as relationships among attributes according to predefined requirements, user's preferences, or partial knowledge in the form of a constraint network. The constraint-based reasoning is employed to produce valid chromosomes using constraint propagation to ensure the genes to comply with the predefined constraint network. The proposed approach is compared with a regular GA and C4.5 using two UCI repository data sets. Better classification accurate rates from CBGA are demonstrated.     

Source code error bound in the excess rate region

The problem of encoding a discrete memoryless source with respect to a single-letter fidelity criterion, using a block code of lengthnand rateR, is considered. The probability of error,p_{n}(R,D), is defined to be the minimum probability, over all such codes, that the source will generate a sequence which cannot be encoded with distortionDor less. For sufficiently largeR, thatp_{n}(R,D)decreases doubly exponentially with blocklength,nis shown. It is known thatp_{n}(R,D) = 0for some finiten, denoted byn_{0}(R,D). An upper bound ton_{0}(R,D)is also presented and numerically evaluated. The results derived hold independently of the source statistics. It is shown that a theorem of Omura and Shohara for symmetric sources is a special case of the results herein. Additionally, a useful characterization ofR ast (D)for row-balanced distortion matrices is obtained.     

NCFSK bit error rate in the presence of unsynchronised co-channelinterferers

The bit error rate (BER) of binary non-coherent frequency shift keying modulation in the presence of multiple unsynchronised co-channel interferers (UCCIs) and Gaussian noise is investigated. It is found that the BER with UCCIs is generally lower than that with synchronised co-channel interferers (SCCIs). The difference between UCCI and SCCI signal-to-interference ratios required to achieve the same BER performance (<10^-2) increases with the number of interferers     

存在定时误差的MPSK信号调制方式识别

接收机存在定时误差时,应用高阶累积量进行MPSK信号调制方式识别会引起识别率下降.本文针对这一问题,提出了一种对接收数据进行盲定时估计并通过插值滤波进行定时恢复的算法.仿真结果表明,对插值滤波后的数据进行调制识别,具有良好的分类性能,对定时误差有很强的适应能力.     

空间X射线通信系统误码率分析

自X射线通信的概念被提出后,大部分研究集中在发射源、收发天线和探测器等关键器件上,而关于传输理论的研究较少。文中旨在建立X射线通信的理论模型,首先建立了X射线通信的功率传输模型和链路方程;其次建立了基于泊松噪声的X射线通信误码率模型,随后建立了X射线通信中的核心参数:通信距离,通信速率,误码率与传输功率之间的关系;最后对不同阳极高压与不同调制方式下探测器端信号光子数进行实验监测,对功率传输方程及误差模型进行验证,测试了X射线通信系统的误码率,理论与实验较为符合,OOK和4 PPM的误码率可达10-4~10-5量级,为空间X射线通信研究建立了理论基础,同时有望对空间X射线通信的工程化提供一定的参考。