多源数据融合建模的寿命预测方法

针对单一传感器在设备状态监测期间不能很好地进行退化建模和剩余使用寿命预测的问题,提出了一种多源数据融合建模的寿命预测方法.首先,根据设备的退化性能,构造了复合健康指标;其次,使用非线性漂移维纳过程对设备进行退化建模,通过使用极大似然法估计模型参数后,推导出设备剩余寿命概率密度函数;最后,对所提出的方法进行了验证,并与单一传感器预测结果进行了对比,结果表明此方法具有较高的准确性.     

基于EM-EKF与隐含比例退化模型的机载电子设备剩余寿命自适应预测

针对现有机载电子设备剩余寿命自适应预测方法在新研小样本条件下,未能综合考虑设备隐含退化建模与漂移系数在线更新的问题,本文提出一种基于期望最大-扩展卡尔曼滤波(Expectation Maximization-Extended Kal-man Filter,EM-EKF)与隐含比例退化模型的机载电子设备剩余寿命自适应预测方法.首先,基于非线性Wiener过程构建带比例关系的设备隐含退化模型;其次,在引入漂移系数更新机制的基础上建立设备退化状态方程,并采用EKF算法同步更新设备退化状态与漂移系数;然后,采用EM-EKF算法实现对退化模型参数的自适应估计;最后,基于全概率公式,推导出设备剩余寿命的概率密度函数.通过对单台微机械陀螺仪实测数据进行分析,验证了本文所提方法具有更好的模型拟合性与预测准确性.     

RBF网络用于性能退化的可靠性评估

针对无法用数学式准确描述退化量与环境因子间复杂非线性关系的问题,提出了一种基于RBF网络的退化轨迹建模方法.利用RBF网络能够逼近任意非线性函数的特性,进行退化轨迹的建模,并结合失效值预测产品寿命.将所有估计寿命作为完全失效数据进行可靠性评估,有效地解决了失效数据少的问题.通过对疲劳裂纹增长数据的RBF网络建模分析,证明RBF网络具有很好的函数逼近能力,寿命预测结果非常理想.经验证,在更少的退化数据下,RBF网络仍能够较好地模拟退化轨迹,寿命预测精度较高.     

融合随机退化过程与失效率建模的设备剩余寿命预测方法

剩余寿命预测对于设备的维修与保养具有十分重要的意义。现有的剩余寿命预测方法大多只利用了设备的当前退化信息,对设备的历史寿命信息没有充分利用,而这些信息往往包含着设备寿命的演化信息,对于准确预测设备的剩余寿命具有重要意义。针对这个问题,提出了一种融合随机退化过程与失效率建模的设备剩余寿命预测方法。该方法首先将设备的退化过程建模为Wiener过程,然后利用Cox比例失效模型建模的方法融合设备退化过程对设备失效率的影响,由此达到利用设备历史监测信息的目的。进一步通过Bayes方法,利用当前退化监测信息对退化过程模型的参数进行更新,基于此进行剩余寿命预测,从而实现设备历史数据与当前数据的有效融合。最后,通过激光发生器的退化测量数据验证了提出的方法,说明该方法是有效的,具有一定的应用价值。     

基于机理建模与大数据技术的风电设备故障诊断与预测分析

阐述风电设备故障诊断与预测的特点、机理建模技术和大数据技术的原理。探讨基于机理建模与大数据技术的风电设备故障诊断与预测方法、典型案例和实践应用,分析挑战和未来发展。     

基于随机退化数据建模的设备剩余寿命自适应预测方法

针对现有剩余寿命预测研究中需要多个同类设备历史数据离线估计模型参数的问题,本文提出了一种基于退化数据建模的服役设备剩余寿命自适应预测方法.该方法,利用指数随机退化模型来建模设备的退化过程,基于退化监测数据运用Bayesian方法更新模型的随机参数,进而得到剩余寿命的概率分布函数及点估计.区别于现有方法,本文方法基于设备到当前时刻的监测数据,利用期望最大化算法对模型中的非随机未知参数进行在线估计,由此无需多个同类设备历史数据.最后,通过数值仿真与实例分析,验证了本文方法在剩余寿命预测时的有效性.     

基于逆高斯过程和证据推理的退化建模方法

为解决高可靠性设备的剩余寿命预测问题,针对寿命数据缺少、物理模型难以建立的情况,结合单调退化数据,采用逆高斯退化模型,对设备的退化过程进行建模;通过参数估计的方法得到退化模型,进而预测设备的剩余寿命。在有同批次多组数据都能对逆高斯模型进行参数估计的情况下,将会面临数据融合问题。采用基于证据推理(ER)的方法对多源数据进行融合处理,引入属性权重的概念,以此更加准确地估计逆高斯模型的参数。最后,通过实验仿真,证明了所提方法能够得到较为可信的参数估计结果。     

基于粒子滤波的高频金融时间序列预测

高频金融时间序列呈现出强烈的非高斯特性,已经不能采用传统的统计分析方法对其进行分析与预测,通常采用基于极限思想的已实现波动理论进行高频数据的建模.针对市场运作中的高频数据采集数量有限而不能准确估计"已实现"波动率的局限性,提出一种新的预测方法:在对"已实现"波动率建模的基础上,采用适合于非高斯非线性过程的粒子滤波技术对波动率进行估计与预测,可以处理单日内的高频交易数据.将此算法应用于日内高频微软股价数据预测,得到了较好的实证效果.     

基于长短期记忆神经网络的短期负荷预测

准确的电力负荷预测是电力系统安全、稳定、经济、优质运行的前提,负荷预测的本质是通过历史数据对未来负荷情况做出预先估计。电量的快速增长和用户的多元化对负荷预测提出了更高的要求。文中提出了一种基于长短期记忆网络的负荷预测方法,利用长短期网络数据驱动和对时间序列建模强的特点,对于含非线性、不确定性的系统,提取其负荷数据中的周期特征,具有较强的自适应性。以真实数据为算例,验证了方法的有效性。     

融合非线性加速退化模型与失效率模型的产品寿命预测方法

针对高可靠性产品寿命数据少、获取成本高的问题,基于充分利用产品在研制、加速试验等不同环境下的退化数据、失效数据等可靠性数据的思想,提出了一种融合非线性加速退化模型和失效率模型的产品寿命预测方法.首先,根据退化数据对非线性退化过程进行分析,估计退化过程的参数;然后,根据加速退化数据及相应的加速退化模型估计加速退化模型的参数,从而得到退化参数与应力之间的关系.进一步,利用比例风险模型融合产品的寿命数据和未失效截尾数据,并基于此计算产品的可靠度函数、预测产品的寿命.实例应用验证了所提方法的有效性,同时说明了所提方法的应用价值.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks