Point and Interval Estimation, From One-Order Statistic, of the Location Parameter of an Extreme-Value Distribution with Known Scale Parameter and of the Scale Parameter of a Weibull Distribution with Known Shape Parameter

This paper derives a one-order statistic estimator ?mn b for the location parameter of the (first) extreme-value distribution of smallest values with cumulative distribution function F(x;u,b) = 1 - exp {-exp[(x-u)/b]} using the minimum-variance unbiased one-order statistic estimator for the scale parameter of an exponential distribution, as was done in an earlier paper for the scale parameter of a Weibull distribution. It is shown that exact confidence bounds, based on one-order statistic, can be easily derived for the location parameter of the extreme-value distribution and for the scale parameter of the Weibull distribution, using exact confidence bounds for the scale parameter of the exponential distribution. The estimator for u is shown to be b ln cmn + xmn, where xmn is the mth order statistic from an ordered sample of size n from the extreme-value distribution with scale parameter b and Cmn is the coefficient for a one-order statistic estimator of the scale parameter of an exponential distribution. Values of the factor cmn, which have previously viously been tabulated for n = 1(1)20, are given for n = 21(1)40. The ratios of the mean-square-errors of the maximum-likelihood estimators based on m order statistics to those of the one-order statistic estimators for the location parameter of the extreme-value distribution and the scale parameter of the Weibull distribution are investigated by Monte Carlo methods. The use of the table and related tables is discussed and illustrated by numerical examples.     

An Optimal Coding Scheme for a Certain Type of Ensemble

An optimal coding scheme is offered for binary messages with a limited number of successive runs of length 1 (i.e., strings of the form 010101..., in the messages, have a known limited length). A practical example is given of a case where such messages are found.     

Estimators for Parameters of a Series System Under an Attribute Life Test Situation

Estimators for failure-law parameters are derived for the components of a series system under an attribute life test situation where the parameters of the failure laws are unequal. Exponential, Rayleigh, mixed exponential and Rayleigh, and a special case of the Weibull failure models are treated. An example uses simulated data for a 10-component system.     

某型计算输出机试验台的设计

以计算机的ISA总线为基础,对它的外围电路进行研究;以静态存储器作为共享存储介质,接口电路的设计包括各控制接口设计,标志逻辑电路设计以及可编程定时计数器的设计,该装置能对输出机进行各项检查。运行试验表明,该系统性能稳定,结构简单,调试方便,可作为对计算机ISA总线进一步研发的配套设备。     

On a Test for Equality of the Means of Two Independent Poisson Distributions

In this paper, an exact method is studied for testing the equality of means of two independent Poisson distributions. The method allows for sampling over different time durations and thus, one can compare the mean time between failures of an equipment, by observing it for, say, a month, to the MTBF of another equipment which has been under observation for say six months. The purpose of the test for a given situation is discussed, and examples are given which illustrate the usefulness of the test. Extensive tables and graphs are included for those readers who wish to utilize the results.     

GaAs MESFET微波散射参数计算

Shur等人提出了用Gunn畴的形成来说明GaAs MESFET中的电流饱和效应.本文叙述了基于这种模式的GaAs MESFET等效电路分析表示式,进而计算S参数.文中用这些结果对具体器件进行了计算,并与测量值比效,两者相当一致.     

某高炮火控系统测试序列的优化

火控系统是一种大型的电子装备,由于其功能繁琐、结构复杂,维修测试时十分不便。常规的顺序测试法和目的测试法都容易造成重复测试或冗余测试,不仅加大了测试工作量,更会对正常的测试序列造成干扰。有必要采用一种科学的测试优化方法,设计最准确、最合理的测试序列,以降低装备的维修难度,提高维修的效率与效益。以某高炮火控系统为例,介绍了列表寻优法的工作过程,阐述了信息流模型的原理与构建。在此基础上探讨了借助信息流模型,利用列表寻优法优化测试序列。并结合具体的装备结构,给出了其每一结构层次的测试序列优化结果。基于此思路,对构建大型电子装备的故障诊断隔离体系进行了初步探索。     

某型管理控制设备数字口检测方法的设计

某型管理控制设备是一部接口关系多、管理流程复杂的设备。对该设备数字接口的检测方法进行了研究,设计了一套专门的检测装置,并设计了对和设备数字口相关的管理功能性能进行自动检测的方法。     

Comparison of a Set of Power Distribution Parameters for Intraoperative EEG Monitoring

This study was conducted to compare the relative performance of 19 univariate EEG power distribution parameters in terms of their sensitivity to changes in the background (stationary) EEG activity and insensitivity to broad-band interference. Each of the parameters partitioned the power spectrum into two frequency subbands, each subband containing a fixed specific percentage of the total power. The EEG signals recorded from ten patients during induction with thiopental sodium were used in the study. Two sensitivity functions were defined to compare the sensitivity of the parameters to the effects of thiopental sodium. Parameter changes were compared to bandwidth changes during induction to evaluate their sensitivity to broad-band interference. The results of the study showed that the parameters in the middle of the percentile scale were more sensitive to background EEG changes produced by thiopental sodium than were those at either end of the scale. Sensitivity to broad-band interference was found to be directly proportional to percentile. Within the limits of this study, a parameter between the 25th and 30th percentiles would be the most suitable parameter to monitor intraoperatively.     

基于步进加速退化试验的某型电连接器可靠性评估

某导弹电连接器属于高可靠性、长寿命产品,在短时间内很难获取其失效数据。为了评估其可靠性,在分析其失效机理的基础上设计了步进应力加速退化试验,通过分析加速退化数据外推出产品在正常工作应力水平下的可靠度函数。试验中,以电连接器的接触电阻作为性能参量,选取温度作为加速应力。数据分析时利用Wiener随机过程对样品退化进行建模,为了提高模型参数的估计精度,采用极大似然法对所有性能退化数据进行整体统计推断。结果表明,提出的基于加速退化数据分析的方法实用、有效,实现了某导弹电连接器的可靠性评估并可为其他高可靠性产品的可靠性评估工作提供参考。     

有关无功负荷最优分配的一个常用算例的修正

本文讨论了"电力系统分析"课程中有关无功功率最优分配的一个常用算例,指出了目前解析中的问题,并作了修正.由于系统中没有平衡节点来补充线路中的有功损失,确定各发电机的有功出力时需要考虑有功网损的影响.分配无功负荷时应将无功平衡方程、有功平衡方程和等微增率准则建立的方程联立求解.计算结果显示,考虑了线路有功网损之后,能够同时满足有功功率平衡和无功功率平衡,无功负荷的最优分配与有功负荷的分配有关.     

A Stability Test for a Class of Linear, Active Two-Ports with Uncertain Parameters

A new procedure is presented for testing the stability of lumped, linear, active, time-invariant two-ports. The mare advantage of this procedure is that it can consider conditional stability when the passive terminating impedances are limited to only a small subset of all passive impedances represented by the entire right half of the complex plane (RHP). The method can be easily computerized. It is especially useful when only the numerical values of the two-port parameters at various frequencies are known. One version of such a computer program is currently in use at Bell Laboratories for studying the stability properties of two-wire voice-frequency telephone circuits containing E6 type repeaters.     

水冷式微波偶极子辐射器在生物介质中的SAR分布计算

本文从电磁场理论模型出发，分析地腔内水冷式微波偶极子辐射器在生物介质中的近场辐射特性，计算得到有水冷时的比吸收率（ＳＡＲ）分布形态。与无水冷时的ＳＡＲ分布比较表明，水冷可改善热区分布，增加治疗深度。该结果与工程经验和临床实际基本相符。     

BER Calculation and Investigation of Optimal Single User Detector for a BPSK Signal Contaminated by Cochannel Interferer

We propose an optimal single user detector (OSUD) for a binary phase shift keying (BPSK) signal corrupted by a cochannel interferer and additive white Gaussian noise (AWGN). We obtain an analytical expression for the detector bit error rate (BER). The capacity of this channel is also investigated to interpret the BER performance of the optimal detectors.     

Distribution of a random walk with an application to a truncated nonparametric sequential test

Explicit expressions for the probability of reaching a given position at each stage of a random walk are derived for the case of absorbing boundaries. Utilizing these results, exact expressions for the power function and the average sample number function of a truncated nonparametric sequential test are obtained. Some numerical examples are also given.     

大功率CO2混合模激光束传输参数的精确测量

根据大功率 CO2 混合模激光束横截面强度分布的变化规律 ,任选两个横截面的强度分布 ,采用数值迭代方法 ,精确计算出混合模传输的光学参数。     

可控温大功率LED光强空间分布测试系统的设计

发光二极管(LED)的光强空间分布特性决定了它能否满足特定场合的应用。大功率LED由于发热量大,其绝对光强空间分布(LISD)的测试也必须在特定热沉温度下进行才能得到准确可靠的结果。设计了一个可对大功率LED进行热沉温度控制且快速实现LISD自动测试的系统。该自动测试系统基于LEDGON-100测角光度计及其高精度的二维旋转台,配合测试适配器、温度控制器、光度探头、Keithley 2400源表和测试软件组成。测试软件基于Delphi程序语言开发。在控温条件下,该LISD自动测试系统稳定可靠,测试时间大大缩短,测试结果实时直观。利用该自动测试系统对具有朗伯型和蝙蝠翼型两大LISD类型的LED进行测试,获得它们的二维LISD和三维LISD。实验结果表明:随着热沉温度的增加,光强绝对值下降,而相对LISD却不变。     

腔长250mmHe—Ne激光管TEM_（00）模参数的最佳匹配试验

应用正交试验的方法对腔长２５０ｍｍＨｅ－Ｎｅ激光管ＴＥＭ（００）模参数进行试验，得到了ＴＥＭ（００）模参数的最佳匹配值，并将其应用于成批生产，经过近十年，单模率一直稳定在９０％以上。     

基于LabVIEW的某探测组件自动化测试平台设计

本文设计了某探测组件自动化测试平台,通过USBCANⅡ高性能CAN接口卡结合LABVIEW“数据流”框图式编程语言,实现了测量的自动化、测试数据的可视化、以及数据记录的有序管理;通过动态调用子VI,实现了两个终端界面并行运行且相互独立,完成了多个线程之间实时的数据交换;通过验证证实了自动化测试平台设计方案的可行性与便捷性,既节省了测试测量时间,又提高了测试测量的精确度,具有一定的通用性。     

Design and Implementation of an Optimal Receptor for a Non Manipulated MSSR Antenna Electromagnetic Field Reconstruction

While the usual practice on antenna metrology supposes an intense manipulation of the radiation system in order to avoid as much as possible the environmental stochastic variables foreign to ideal radiation conditions, here we propose an algorithm of an observant procedure in which the radiant system is not manipulated at all. An optimal receptor is also proposed, and its viability is shown in the particular case of the metrology of monopulse secondary surveillance radar (MSSR) Antennas. After the study of the characteristics and the error model obtained, the proposed system potentially offers an alternative procedure to traditional methods of measuring MSSR antennas, avoiding the process of stopping its normal operation for an in-depth study.