基于子带平均的宽带源个数估计方法

本文提出了一种相关宽带源个数估计的方法。该方法首先阵列采样数据分段并进行FFT变换．得到若干个窄带信号，然后分别对每一个窄带信号进行处理，最后对各窄带的处理结果进行加权综合来得到宽带源个数的估计结果，采用空间平滑技术可处理相关宽带源。计算机仿真结果证实了方法的可行性。     

直插式电器插头测试项目探讨

为保证直插式电器的安全使用,分析直插式电器插头易出现的问题,阐明了家电标准对直插式电器插头的考核项目,提出了我国扁形插头应测试的项目。     

一种估计宽带信号源数目的新方法

信号源数目估计是波达方向（DOA）估计的基础。基于噪声特征值的统计特性,文章在宽带信号条件下,基于各个频率点下的阵列采样协方差矩阵的噪声特征值在平面直角坐标系中几乎处于同一条直线上这一统计特性,提出了一种新的估计宽带信号源数目的方法,该方法简单且易于实现。最后通过计算机仿真验证了此方法的有效性和优越性。     

行波管阴极的寿命试验

微波器件的寿命往往取决于阴极的寿命,做好阴极寿命的测试是非常必要的.本文选择了常规寿命试验的方式,采用了阳控枪和水冷收集极的短管结构,在阴极工作温度1020℃、脉冲工作比10％、初始发射电流6A/cm2电流密度的状态下,进行行波管阴极寿命试验.截止目前,该试验还在进行中,累积寿命时间达8200h.     

一种新的宽带信号源数目快速估计方法

信号源数目估计是波达方向(DOA)估计的基础.基于两个子阵接收数据的信号子空间的旋转不变性,利用Lanczos方法来求解多级维纳滤波器的匹配滤波器组,即子阵的信号子空间,本文提出了一种新的宽带信号源数目快速估计方法.该方法不需要计算协方差矩阵或对其进行特征值分解,避免了特征值分解的大运算量.最后通过计算机仿真验证了本文方法的有效性和优越性.     

加速寿命试验评估功率发光二极管平均寿命

采用恒定温度应力的加速寿命试验,对XR7090BL-LI-B3-0-0001功率型蓝色发光二极管(LED)的平均寿命进行了评估.参照已有的发光管光功率缓慢退化公式,采用图估法和数值分析法进行试验数据处理,得到了该型号功率发光二极管工作结温不超过80℃、光通量衰减至70%的平均寿命.

Abstract：

Based on constant temperature stress,an accelerate life test was carried out on a type of power light-emitting diodes (LEDs) named XR7090BL-L1-B3-0-0001.Yamaoshi's slow LED degradation formula was consulted and test data were processed through chart eastimate and numerical analysis method.Then mean life of XR7090BL-L1-B3-0-0001 satisfying the conditions that the working junction temperature was lower than 80 ℃ and the luminous flux decreased to 70% were finally obtained.     

VLSI使用寿命的一种估计方法

文章提出了一种ＶＬＳＩ使用的实用估计方法,该方法充分考虑了工作条件对集成电路寿命的影响,使估计结果更切合实际。     

Minimizing Life Test Costs

Requirements for unusual operating environments and high reliability necessitate qualification and life tests of new or changed components. Considering these requirements, test planners determine test environments, instrumentation, and the number of parts and elapsed hours for the life test. A technique is presented to deal with one specific aspect of test planning?the selection of that number of test units that will result in the lowest total cost of the life test.     

电子对抗装备例行试验项目的选择及应用

批量生产阶段环境试验的目的是为监控生产过程提供信息。根据大量的整机环境例行试验中发生的故障信息统计结果,从顾客关注的不同焦点,对批量生产产品整机环境试验暴露出的缺陷进行分析,为针对性地选择电子对抗装备整机例行试验项目提供参考。     

Simple and Efficient Nonparametric Method for Estimating the Number of Signals Without Eigendecomposition

Inspired by the computational simplicity and numerical stability of QR decomposition, a nonparametric method for estimating the number of signals without eigendecomposition (MENSE) is proposed for the coherent narrowband signals impinging on a uniform linear array (ULA). By exploiting the array geometry and its shift invariance property to decorrelate the coherency of signals through subarray averaging, the number of signals is revealed in the rank of the QR upper-trapezoidal factor of the autoproduct of a combined Hankel matrix formed from the cross correlations between some sensor data. Since the infection of additive noise is defused, signal detection capability is improved. A new detection criterion is then formulated in terms of the row elements of the QR upper-triangular factor when finite array data are available, and the number of signals is determined as a value of the running index for which this ratio criterion is maximized, where the QR decomposition with column pivoting is also used to improve detection performance. The statistical analysis clarifies that the MENSE detection criterion is asymptotically consistent. Furthermore, the proposed MENSE algorithm is robust against the array uncertainties including sensor gain and phase errors and mutual coupling and against the deviations from the spatial homogeneity of noise model. The effectiveness of the MENSE is verified through numerical examples, and the simulation results show that the MENSE is superior in detecting closely spaced signals with a small number of snapshots and/or at relatively low signal-to-noise ratio (SNR)     

Technique for Estimating the Number of Active Flows in High‐Speed Networks

The online collection of coarse‐grained traffic information, such as the total number of flows, is gaining in importance due to a wide range of applications, such as congestion control and network security. In this paper, we focus on an active queue management scheme called SRED since it estimates the number of active flows and uses the quantity to indicate the level of congestion. However, SRED has several limitations, such as instability in estimating the number of active flows and underestimation of active flows in the presence of non‐responsive traffic. We present a Markov model to examine the capability of SRED in estimating the number of flows. We show how the SRED cache hit rate can be used to quantify the number of active flows. We then propose a modified SRED scheme, called hash‐based two‐level caching (HaTCh), which uses hashing and a two‐level caching mechanism to accurately estimate the number of active flows under various workloads. Simulation results indicate that the proposed scheme provides a more accurate estimation of the number of active flows than SRED, stabilizes the estimation with respect to workload fluctuations, and prevents performance degradation by efficiently isolating non‐responsive flows.     

Estimating the Number of Clusters via System Evolution for Cluster Analysis of Gene Expression Data

The estimation of the number of clusters (NC) is one of crucial problems in the cluster analysis of gene expression data. Most approaches available give their answers without the intuitive information about separable degrees between clusters. However, this information is useful for understanding cluster structures. To provide this information, we propose system evolution (SE) method to estimate NC based on partitioning around medoids (PAM) clustering algorithm. SE analyzes cluster structures of a dataset from the viewpoint of a pseudothermodynamics system. The system will go to its stable equilibrium state, at which the optimal NC is found, via its partitioning process and merging process. The experimental results on simulated and real gene expression data demonstrate that the SE works well on the data with well-separated clusters and the one with slightly overlapping clusters.     

LED加速寿命试验方法的研究

给出了一种缩短试验时间求取LED平均寿命的方法,利用"亚玛卡西"的发光管光功率缓慢退化公式,由退化系数求得不同应力温度下LED失效时间,再用数值解析法得到正常温度应力下的LED平均寿命.     

一种步进应力加速寿命试验数理统计分析法

本文提出了处理步进应力加速寿命试验的“时间等效”数学模型,并用它把寿命分布服从对数正态分布(或威布尔分布)、有m步的一次步进应力加速寿命试验变为有m级应力的恒定应力加速寿命试验来分析处理.并且推导出了它们之间的变换计算公式.用本法处理质子轰击隔离WC56型砷化镓场效应管步进应力加速寿命试验,获得了满意的结果.     

A Technique for Estimating the Minimum Number of Frequencies Required for Urban Mobile Radio Communication

In this correspondence paper a technique for estimating the minimum number of frequencies required for Urban Mobile Radio Communication is presented. The technique is algebraic in origin and can be implemented as a computer algorithm.     

Probability Limits for Life Test Data

In this paper a general theory for constructing probability limits for life test data is briefly discussed. It is then applied to a set of life test data to determine which of three specified Weibull distributions give the best fit.     

Likelihood Inference for Life Test Data

This paper reviews the basic ideas of likelihood inference and applies them to some reliability and life testing problems connected with the exponential distribution. Various censoring schemes are considered and the likelihood approach is shown to provide a unified framework for treating exact solutions to estimation, prediction, and population-comparison problems. These solutions are provided in a well defined but non-probabilistic form. The classical s-confidence procedures depend strongly on imaginary exact repetitions of the form of the experiment being analyzed. This is often unrealistic and impractical. The data on hand can be directly analyzed by examining the likelihood function.     

影响电解电容器漏电流的因素

以铝和钽电解电容器为例,特别强调了原材料对漏电流值的影响;分析了工作温度的影响作用,除了一般的离子电导随着温度上升而成指数式增加的规律外,还指出了由于各类电容器有各自的特点,因此所受的影响也各不相同,具有一定的参考价值.     

多功能环境模拟试验舱——空气试验领域智能化试验室

多功能环境模拟试验舱为可模拟各种环境因子（包括温湿度、换气率、压力、风速、光照等）,试验人员可进行舱外操作试验,全过程电脑监控的密闭可视试验室。可进行生命体暴露、污染物挥发、净化产品性能检测、环境因素影响分析等实验。对国内外与室内空气品质有关的检测规范中提及的模拟现场试验舱进行分类,方便使用者与建造者之间的技术沟通。