Adaptive Wavelets Based on Second Generation Wavelet Transform and Their Applications to Trend Analysis and Prediction

In order to make trend analysis and prediction to acquisition data in a mechanical equipment condition monitoring system, a new method of trend feature extraction and prediction of acquisition data is proposed which constructs an adaptive wavelet on the acquisition data by means of second generation wavelet transform (SGWT). Firstly, taking the vanishing moment number of the predictor as a constraint, the linear predictor and updater are designed according to the acquisition data by using symmetrical interpolating scheme. Then the trend of the data is obtained through doing SGWT decomposition, threshold processing and SGWT reconstruction. Secondly, under the constraint of the vanishing moment number of the predictor, another predictor based on the acquisition data is devised to predict the future trend of the data using a non-symmetrical interpolating scheme. A one-step prediction algorithm is presented to predict the future evolution trend with historical data. The proposed method obtained a desirable effect in peak-to-peak value trend analysis for a machine set in an oil refinery.     

Volterra小波变换最优阈值的混沌去噪方法

针对混沌信号小波去噪中难以确定最优阈值的问题,提出一种Volterra小波变换最优阈值的判定方法。利用小波变换将混沌信号分解,对不同尺度下的小波信号设定浮动因子以调节阈值大小,最后根据混沌序列Volterra自适应预测的相对误差选取最优阈值。利用该方法对不同维度的Lorenz混沌时间序列进行了去噪研究,结果表明所提方法是有效的。     

半参数回归模型拟极大似然估计的弱相合性

本文考虑一类固定设计的半参数回归模型,其误差为一阶自回归时间序列。用权函数及拟极大似然估计方法得到了一些参数及非参数的拟极大似然估计量,在适当的条件下,研究了它们的弱相合性,从而丰富了该类半参数回归模型的估计理论与方法。     

非线性科学及其在医学中的应用

简要介绍了非线性科学中的分形维方法和信息熵方法及其用于房颤信息的处理和分析，计算了未房颤时P波的及房颤时f波的格子维和信息熵，特别是，比较了未房颤时和发生房颤时的相关计算结果的显著差别，从而很容易判断是否发生了房颤。     

State-space based analysis and forecasting of macroscopic road safety trends in Greece

In this paper, macroscopic road safety trends in Greece are analyzed using state-space models and data for 52 years (1960–2011). Seemingly unrelated time series equations (SUTSE) models are developed first, followed by richer latent risk time-series (LRT) models. As reliable estimates of vehicle-kilometers are not available for Greece, the number of vehicles in circulation is used as a proxy to the exposure. Alternative considered models are presented and discussed, including diagnostics for the assessment of their model quality and recommendations for further enrichment of this model. Important interventions were incorporated in the models developed (1986 financial crisis, 1991 old-car exchange scheme, 1996 new road fatality definition) and found statistically significant. Furthermore, the forecasting results using data up to 2008 were compared with final actual data (2009–2011) indicating that the models perform properly, even in unusual situations, like the current strong financial crisis in Greece. Forecasting results up to 2020 are also presented and compared with the forecasts of a model that explicitly considers the currently on-going recession. Modeling the recession, and assuming that it will end by 2013, results in more reasonable estimates of risk and vehicle-kilometers for the 2020 horizon. This research demonstrates the benefits of using advanced state-space modeling techniques for modeling macroscopic road safety trends, such as allowing the explicit modeling of interventions. The challenges associated with the application of such state-of-the-art models for macroscopic phenomena, such as traffic fatalities in a region or country, are also highlighted. Furthermore, it is demonstrated that it is possible to apply such complex models using the relatively short time-series that are available in macroscopic road safety analysis.     

Economic statistical design of a T2 control chart with double warning lines

Recent studies have shown that enhancing the common T² control chart by using variable sample sizes (VSS) and variable sample intervals (VSI) sampling policies with a double warning line scheme (DWL) yields improvements in shift detection times over either pure VSI or VSS schemes in detecting almost all shifts in the process mean. In this paper, we look at this problem from an economical perspective, certainly at least as an important criterion as shift detection time if one considers what occurs in the industry today. Our method is to first construct a cost model to find the economic statistical design (ESD) of the DWL T² control chart using the general model of Lorenzen and Vance (Technometrics 1986; 28 :3–11). Subsequently, we find the values of the chart parameters which minimize the cost model using a genetic algorithm optimization method. Cost comparisons of Fixed ratio sampling, VSI, VSS, VSIVSS with DWL, and multivariate exponentially weighted moving average (MEWMA) charts are made, which indicate the economic efficacy of using either VSIVSS with DWL or MEWMA charts in practice if cost minimization is of interest to the control chart user. Copyright © 2010 John Wiley & Sons, Ltd.     

Consensus Values,Regressions, and Weighting Factors

An extension to the theory of consensus values is presented. Consensus values are calculated from averages obtained from different sources of measurement. Each source may have its own variability. For each average a weighting factor is calculated, consisting of contributions from both the within- and the between-source variability. An iteration procedure is used and calculational details are presented. An outline of a proof for the convergence of the procedure is given. Consensus values are described for both the case of the weighted average and the weighted regression.     

ECG steganography based on tunable Q‐factor wavelet transform and singular value decomposition

The article presents a novel ECG steganography scheme based on the tunable Q‐factor wavelet transformation (TQWT) and also singular value decomposition (SVD) techniques that ensure better safety and confidentiality of patient information. Initial parameters such as Q, r, and J are used to decompose the cover signal into individual frequency sub‐bands with the tunable Q‐factor wavelet transform (TQWT). The singular value decomposition (SVD) technique is used to further decompose high‐frequency sub‐band coefficients into singular values. The watermark information is then embedded with high‐frequency sub‐band coefficients by involving the quantization process. The performance of this proposed system is successfully evaluated by considering various metrics, such as peak signal to noise ratio (PSNR), structural similarity index (SSIM), percentage residual difference (PRD), and bit error rate (BER). The simulation results of the proposed scheme are observed to be better than other traditional algorithms.     

航空发动机试飞中转静子碰摩故障信号处理 的希尔伯特－黄变换（HHT）方法

时变信号处理的新方法希尔伯特－黄变换,是把一时间序列数据通过经验模态分解（Empirical Mode Decomposition,简称EMD）成本征模函数组（Intrinsic Mode Function, 简称IMF）,然后经希尔伯特变换（Hilbert Transformation,简称HT）获得频谱的信号时频分析方法引入到航空发动机转静子碰摩故障振动信号处理领域。该方法的理论和算法为用MATLAB语言编写分析程序,再用仿真信号验证程序的正确性和有效性;然后对飞行试验中获得的故障振动信号进行分析。结果表明,用EMD和HT方法对航空发动机转静子碰摩故障振动信号进行时频分析是有效的。     

Encapsulation of ferro- and ferricyanide complexes inside ZSM-5 zeolite synthesized from rice straw: Implications for synthesis of Prussian blue pigment

Encapsulation of [Fe(CN)₆]⁴⁻ and [Fe(CN)₆]³⁻ complexes in the intracrystalline pores of ZSM-5 zeolite, Fe^IIL/Z and Fe^IIIL/Z respectively, by the zeolite synthesis method was reported. The modified zeolites were characterized by powder XRD, FT-IR and UV–vis spectroscopy. The nitrogen adsorption isotherms allow for the evaluation of pore structure of the complex-modified zeolites, whereas the thermal analysis (TGA/DTA) measurements provide insight into the decomposition products of the immobilized complexes. The modified zeolites exhibited smaller pore volumes and surface areas as compared with those of unpromoted ZSM-5, suggesting the inclusion of iron cyanides inside the interconnecting channels of ZSM-5. While the ferricyanide complex enhanced the formation of highly crystalline zeolite, the ferrocyanide one resulted in a lesser effect. The electronic spectra of the colloidal species developed when Fe^IIIL/Z brought in contact with an aqueous solution of [Fe(CN)₆]³⁻ exhibit absorptions attributed to CN⁻ → iron charge-transfer. New bands at 294 and 319 nm due to d–d transitions of Fe^III tetrahedral monomeric moieties were emitted concurrently under successive adsorption of _[Fe₍CN_)6]aq³⁻${{\left[\text{Fe}{\left(\text{CN}\right)}_6\right]}_{\text{aq}}}^{3-}$ over Fe^IIIL/Z, along with a broad band at 555 nm assigned to polymeric [Fe^II–C–N–Fe^III] of Prussian blue (PB). The FT-IR spectra of Fe^III/IIL/Z devoted to the adsorption of an aqueous solution of [Fe(CN)₆]³⁻ showed a band at 2092 cm⁻¹ assigned to the C–N stretch in the Fe^II–CN–Fe^III linkages. The vibrations attributable to Fe–O–Si bonding along with hydrocarbon and nitroprusside appeared only in the spectrum of Fe^IIIL/Z, thus was found to be strong evidence for the mutual interaction between [Fe(CN)₆]³⁻ and the latter sample.     

基于OVMD与SVR的水电机组振动趋势预测

为更好地预测水电机组振动趋势,研究提出了一种基于最优变分模态分解（OVMD）与支持向量回归（SVR）的水电机组振动趋势预测模型。首先基于中心频率观察法与残差指标最小化准则确定OVMD的分解参数,采用OVMD将非平稳振动序列分解为一系列模态函数,并对各模态函数分别进行相空间重构,构建状态矩阵,进而得到SVR回归预测模型的输入、输出,再采用交叉验证的网格搜索策略优化各SVR模型的参数,并分别进行回归预测,最后对所有SVR预测结果进行求和,得到原始振动趋势的预测值。研究对某大型混流式水电机组的振动监测数据进行预测试验,并进行对比分析,结果表明该模型可有效预测水电机组振动趋势。     

General time‐dependent C(t) and J(t) estimation equations for elastic‐plastic‐creep fracture mechanics analysis

This paper presents equations for estimating the crack tip characterizing parameters C(t) and J(t), for general elastic‐plastic‐creep conditions where the power‐law creep and plasticity stress exponents differ, by modifying the plasticity correction term in published equations. The plasticity correction term in the newly proposed equations is given in terms of the initial elastic‐plastic and steady‐state creep stress fields. The predicted C(t) and J(t) results are validated by comparison with systematic elastic‐plastic‐creep FE results. Good agreement with the FE results is found.     

Ethyl group as matrix modifier and inducer of ordered domains in hybrid xerogels synthesised in acidic media using ethyltriethoxysilane (ETEOS) and tetraethoxysilane (TEOS) as precursors

Hybrid silica xerogels favourably combine the properties of organic and inorganic components in one material; consequently these materials are useful for multiple applications. The versatility and mild synthetic conditions provided by the sol-gel process are ideal for the synthesis of hybrid materials. The specific aims of this study were to synthesise hybrid xerogels in acidic media using tetraethoxysilane (TEOS) and ethyltriethoxysilane (ETEOS) as silica precursors, and to assess the role of the ethyl group as a matrix modifier and inducer of ordered domains in xerogels. All xerogels were synthesised at pH 4.5, at 60 °C, with 1:4.75:5.5 TEOS:EtOH:H₂O molar ratio. Gelation time exponentially increased with the ETEOS molar ratio. Incorporation of the ethyl groups into the structure of xerogels reduced cross-linking, increased the average siloxane bond length, and promoted the formation of ordered domains. As a result, a transition from Qⁿ to Tⁿ signals detected in the ²⁹Si NMR spectra, the Si–O structural band in the FTIR spectra shifted to lower wavelength, and a new peak in the XRD pattern at 2θ < 10° appeared in the XRD patterns. Mass spectroscopy detected fragments with high numbers of silicon atoms and a polymeric distribution.     

Simultaneous improvement of strength and ductility in NiAl-Cr(Mo)-Hf near eutectic alloy by small amount of Ti alloying addition

Effects of Ti alloying addition on the microstructure and room temperature compression deformation behavior of a NiAl-Cr(Mo)-Hf near eutectic alloy were investigated by SEM, TEM, EDX and compression test. The results showed that compared with base alloy, the compressive fracture strain and 0.2% yield strength of the Ti-containing alloy were enhanced simultaneously. Disordered (Ti,Hf) solid solution phase together with the blocky Heusler phase Ni₂Al(Ti,Hf) precipitation presented at eutectic cell boundaries is responsible for the enhancement in ductility due to the better deformation ability of (Ti,Hf) solid solution phase. The improvement in strength depends mainly on the solid solution strengthening in NiAl matrix by large amount of Ti due to its larger solid solubility relative to Hf in NiAl.     

板带轧机随机干扰模型与ARMA谱分析

板带轧机随机干扰模型不易建模,是制约轧机随机动力特性研究的主要难点之一。基于某铝热连轧机轧制１２３５铝合金的轧制力随机数据,得到平稳、正态、零均值的时间序列,采用时序分析法建立轧制力的ＡＲＭＡ模型及轧机动态干扰功率谱密度模型,分析了轧制力的ＡＲＭＡ谱特性,采用麦夸特法＋通用全局优化算法,得出便于工程应用的轧制力功率谱表达式,构建轧制力随机干扰模型。对轧制力的预报、轧机动刚度的确定及对轧机与轧制过程的随机动态性研究与分析具有一定的意义。     

Load-strength modelling of mechanics and electronics

The basic conditions for using the load-strength theory is listed. The use of the theory as a modelling tool—a way of thinking, is discussed. The theory is used to explain differences and similarities in failure patterns of mechanics and electronics. Further, real data is shown for load-strength in an electronic system.     

五种二元过渡金属氧化物界面上的相互作用、非晶相结构及催化性能(Ⅰ) 界面非晶相分散作用及体相晶相剩余率的提出

通过固相热反应，以十种不同配比和不同的焙烧制度，在MoO3中分别掺杂Fe2O3、V2O5、TiO2(锐钛矿型）、WO3和ZrO2，制得五种二元氧化物的系列试样。应用XRD、BET、FT-IR、DSC、半导体气敏特性和催化反应探针等表征技术，较系统地研究了这些组分氧化物形成二元氧化物时界面的非晶相分散结构及催化性能，并提出了相应的亚单层的非晶相分散模型。本文首先报道应用XRD，FT-IR和BET表征界面的非晶相分散。研究结果发现，各个组分氧化物的表面大小不同，但每一对组分氧经物在相互掺杂时，在界面上发生了组分氧化物的亚单分子层（meta-monolayer)的非晶相分散以及某些表面化学反应，前者在非晶相含量具有本征性的分散阈值，后者则生成新的化学物种。根据BET比表面积，求算了各组分氧化物在不同二元氧化物中每100m^2的不同的非晶相分散阈值。XRD晶相定量分析和FT-IR差谱法（the differential spectra method)联合证明了非晶相新物种的存在，首次发现非晶相新物种的IR特征吸收峰与分子键价结构的关联。     

PAN基原丝预氧丝炭纤维微结构的几种新的X射线衍射散射定量表征技术

介绍几种新近开发的针对PAN基原丝、预氧丝和炭丝微结构和结构缺陷的X射线衍射与散射定量表征技术,它们是:纤维材料中柱状(椭球状)纳米取向微孔体积分数X射线小角散射定量表征方法;纤维材料中柱状(椭球状)纳米取向微孔取向角的小角散射定量表征方法;预氧丝中链状相与环化相体积分数的小角衍射定量表征方法以及炭纤维中乱层石墨相与单层石墨相的X射线广角衍射定量表征方法等。     

Optimal Resource Allocation and Quality of Service Prediction in Cloud

In the present scenario, cloud computing service provides on-request access to a collection of resources available in remote system that can be shared by numerous clients. Resources are in self-administration; consequently, clients can adjust their usage according to their requirements. Resource usage is estimated and clients can pay according to their utilization. In literature, the existing method describes the usage of various hardware assets. Quality of Service (QoS) needs to be considered for ascertaining the schedule and the access of resources. Adhering with the security arrangement, any additional code is forbidden to ensure the usage of resources complying with QoS. Thus, all monitoring must be done from the hypervisor. To overcome the issues, Robust Resource Allocation and Utilization (RRAU) approach is developed for optimizing the management of its cloud resources. The work hosts a numerous virtual assets which could be expected under the circumstances and it enforces a controlled degree of QoS. The asset assignment calculation is heuristic, which is based on experimental evaluations, RRAU approach with J48 prediction model reduces Job Completion Time (JCT) by 4.75 s, Make Span (MS) 6.25, and Monetary Cost (MC) 4.25 for 15, 25, 35 and 45 resources are compared to the conventional methodologies in cloud environment.