随机森林-相关向量机算法结合中红外光谱法快速测定在用柴油机油酸值

研究了随机森林-相关向量机(RF-RVM)算法与ATR中红外光谱法相结合测定柴油机油样品的酸值的方法。选择了某型车辆发动机在不同情况下所用的柴油机油样品48个,并按GB/T 4945-2002标准所述方法对48个样品的酸值进行测定,测得其酸值在0.59～1.71mg(KOH)·g^(-1)之间。运用SG平滑结合一阶微分对原始光谱图进行预处理,采用RF算法和相关系数法选择了特征波数,并进行RVM建模分析。RF算法选取6个特征波数,不仅大大减少了输入变量数,还使RVM算法建模效果更佳。模型验证集的相关系数为0.922 5,验证集标准偏差为0.091 7。结果表明,RF-RVM算法与红外光谱法相结合能实现在用油酸值的快速而准确的测定。

Improved delay-dependent stability criteria for stochastic systems with time-varying interval delay

The problem of the stability for a class of stochastic systems with time-varying interval delay and the norm-bounded uncertainty is investigated. Utilizing the information of both the lower and the upper bounds of the interval time-varying delay, a novel Lyapunov-Krasovskii functional is constructed. The delay-dependent sufficient criteria are derived in terms of linear matrix inequalities （LMIs）, which can be easily checked by the LMI in the Matlab toolbox. Based on the Jensen integral inequality, neither model transformations nor bounding techniques for cross terms is employed, so the derived criteria are less conservative than the existing results. Meanwhile, the computational complexity of the obtained stability conditions is reduced because no redundant matrix is introduced. A numerical example is given to show the effectiveness and the benefits of the proposed method.

Traffic flow prediction of urban road network based on LSTM-RF model

Traffic flow prediction,as the basis of signal coordination and travel time prediction,has become a research point in the field of transportation.For traffic flow prediction,researchers have proposed a variety of methods,but most of these methods only use the time domain information of traffic flow data to predict the traffic flow,ignoring the impact of spatial correlation on the prediction of target road segment flow,which leads to poor prediction accuracy.In this paper,a traffic flow prediction model called as long short time memory and random forest(LSTM-RF)was proposed based on the combination model.In the process of traffic flow prediction,the long short time memory(LSTM)model was used to extract the time sequence features of the predicted target road segment.Then,the predicted value of LSTM and the collected information of adjacent upstream and downstream sections were simultaneously used as the input features of the random forest model to analyze the spatial-temporal correlation of traffic flow,so as to obtain the final prediction results.The traffic flow data of 132 urban road sections collected by the license plate recognition system in Guiyang City were tested and verified.The results show that the method is better than the single model in prediction accuracy,and the prediction error is obviously reduced compared with the single model.

AUTOCORRELATIONS OF l-SEQUENCES WITH CERTAIN SHIFTS

In this paper, the autocorrelations of maximal period Feedback with Carry Shift Register sequences （l-sequences） are discussed. For an l-sequence a with connection integer q = p^e（e ≥ 2） and period T = p^t-1（p- 1）, and for any integer i, 1 ≤ i ≤ e/2, by calculating the number of certain sets, it is shown that the autocorrelation of a with shift τ= kT/2p^i is Ca（τ） =（-1）^k-1 T/p^2i-1, where 1 ≤ k ≤ 2p^i - 1, and gcd（k,2p^i） = 1. This result shows there do exist some shifts such that the autocorrelations of l-sequences are high although most autocorrelations are low. Such result also holds for the decimations of l-sequences.

利用小波进行多尺度地形生成方法的研究

针对随机中点位移法难以生成符合ｆＢｍ特征的三维地形之缺点，本文把地形看成层次性随机统计过程，提出了利用小波进行多尺度地形生成的新方法，首先利用扩展的随机－相关法按给定的地形参数（均值、地形高程标准差、地形相关长度、地形粗糙度等）形成一定数量用来表示地形骨架的地形特征点，然后与通过小波机制产生的多尺度地形局部细节信号相综合，通过小波多尺度合成获得符合要求的具有任意细节水平的“真实”的三维地形。试验证明这一方法切实可行。

辅助导航二维标量场模拟生成的组合改进算法

模拟生成是解决辅助导航研究中数据源不足的有效手段,而准确反映所用地球物理场的分布特征是算法设计的关键.综合分析辅助导航的匹配定位方式与场源模拟限定,发现建立二维标量场是其基准数据库自动生成共同的基础.本文针对通常的骨架生成算法忽略初始边缘似真性的问题,提出了改进的扩展随机-相关骨架生成方法,并结合附加限定条件的分形细节生成算法建立了组合改进算法.最后采用均方差检验准则验证了其模拟生成二维标量场的匹配适用性.

Stochastic resonance based on correlation coefficient in parallel array of threshold devices

The phenomenon of stochastic resonance （SR） based on the correlation coefficient in a parallel array of threshold devices is discussed. For four representative noises： the Gaussian noise, the uniform noise, the Laplace noise and the Cauchy noise, when the signal is subthreshold, noise can improve the correlation coefficient and SR exists. The efficacy of SR can be significantly enhanced and the maximum of the correlation coefficient can dramatically approach to one as the number of the threshold devices in the parallel array increases. Two theorems are presented to prove that SR has some robustness to noises in the parallel array. These results further extend the applicability of SR in signal processing.

Study on the scales of heterogeneous geologic bodies in random media

In order to study the scale characteristics of heterogeneities in complex media, a random medium is constructed using a statistical method and by changing model parameters （autocorrelation lengths a and b）, the scales of heterogeneous geologic bodies in the horizontal and the vertical Cartesian directions may be varied in the medium. The autocorrelation lengths a and b represent the mean scale of heterogeneous geologic bodies in the horizontal and vertical Cartesian directions in the randQm medium, respectively. Based on this model, the relationship between model autocorrelation lengths and heterogeneous geologic body scales is studied by horizontal velocity variation and standard deviation. The horizontal velocity variation research shows that velocities are in random perturbation. The heterogeneous geologic body scale increases with increasing autocorrelation length. The recursion equation for the relationship between autocorrelation lengths and heterogeneous geologic body scales is determined from the velocity standard deviation research and the actual heterogeneous geologic body scale magnitude can be estimated by the equation.

Probabilistic durability assessment approach of deteriorating RC bridges

A stochastic finite element computational methodology for probabilistic durability assessment of deteriorating reinforced concrete（RC） bridges by considering the time-and space-dependent variabilities is presented.First,finite element analysis with a smeared cracking approach is implemented.The time-dependent bond-slip relationship between steel and concrete,and the stress-strain relationship of corroded steel bars are considered.Secondly,a stochastic finite element-based computational framework for reliability assessment of deteriorating RC bridges is proposed.The spatial and temporal variability of several parameters affecting the reliability of RC bridges is considered.Based on the data reported by several researchers and from field investigations,the Monte Carlo simulation is used to account for the uncertainties in various parameters,including local and general corrosion in rebars,concrete cover depth,surface chloride concentration,chloride diffusion coefficient,and corrosion rate.Finally,the proposed probabilistic durability assessment approach and framework are applied to evaluate the time-dependent reliability of a girder of a RC bridge located on the Tianjin Binhai New Area in China.

Modeling of Rocks with Spatial Distributed Fractures by Random Medium Theory

By using the spectrum expanding theory of random processes and Hudson's crack model,we developed a random medium model for rocks with spatial random distributed number density of cracks. This model could connect the micro-parameters of the cracks with the macro- mechanical properties, and can be effectively applied to model the real inhomogeneous medium. Numerical example indicates that the random distribution characters could be different for different elastic constants under the same random distribution of number density of cracks. By changing the value of the autocorrelation length pair, it is possible to model the difference of the distribution in the two coordinate directions. Numerical modeling results for seismic wave propagating in rocks with random distributed fractures using a staggered high-order finite-difference (SHOFD) are also presented.

EFFECTS OF RANDOM ERRORS ON THE SIDELOBE FOR THE LINEAR ARRAY

The effects of statistically dependent random errors on the sidelobe are analyzed for the linear array. It is shown that the random errors cause a rise in the sidelobe level. The simple formulas can also be obtained for the case of independent random errors.

Coefficient of Partial Correlation and Its Calculation

This thesis offers the general concept of coefficient of partial correlation.Starting with regres-sion analysis,the paper,by using samples,infers the general formula of expressing coefficient of partial correlation by way of simple correlation coefficient.

Analysis of Genetic Diversity of Four Subpopulations of Chimonobambusa rivularis Yi in Sichuan

A study of the genetic diversity within four subpopulations of Chimonobambusa rivularis Yi and adaptations to altitude, habitat and related factors in Qionglai City of Sichuan province in China, analyzed by random amplified polymorphic DNA technique. 22 random primers were selected in the amplification and 375 repetitive loci with 350 polymorphic loci were produced. The total average percentage of amplification loci was 93.3%. The genetic diversity of every subpopulation was medium on （the percentage of amplification loci was 49.33%-66.67%）. The genetic diversity of high altitude samples of Zhengtiantai was lower than that of low altitude Wutonggang＇s. There was no obvious differentiation between two subpopulations of Zhengtiantais. The correlation is very low between altitude and the amplification loci and the genetic distance, Pearson correlation coefficient was 0.431 and 0.488 （P 〈 0.01）. Through investigation, the primary cause of heredity multiplicity drops was that the habitat had been destroyed by tourism development and other human disturbance.

A Novel Masking Scheme for SM3 Based MAC

The Chinese hash algorithm SM3 is verified to be secure enough,but improper hardware implementation may lead to leakage.A masking scheme for SM3 algorithm is proposed to ensure the security of SM3 based Message Authentication Code(MAC).Our scheme was implemented in hardware,which utilizes hardware oriented secure conversion techniques between boolean and arithmetic masking.Security evaluation based on SAKURA-G FPGA board has been done with 2000 power traces from 2000 random plaintexts with random plaintext masks and random key masks.It has been verified that the masked SM3 hardware implementation shows no intermediate value leakage as expected.Our masked SM3 hardware can resist first-order correlation power attack(CPA) and collision correlation attack.

Asymptotics for the Tail Probability of Random Sums with a Heavy-Tailed Random Number and Extended Negatively Dependent Summands

Let （X, Xk ： k ≥ 1） be a sequence of extended negatively dependent random variables with a common distribution F satisfying EX 〉 0.Let τ be a nonnegative integer-valued random variable, independent of {X, Xk ： k ≥ 1}. In this paper, the authors obtain the necessary and sufficient conditions for the random sums Sτ=∑n=1^τ Xn to have a consistently varying tail when the random number τ has a heavier tail than the summands, i.e.,P（X〉x）/P（τ〉x）→0 as x →∞.

Rosenthal's inequalities for independent and negatively dependent random variables under sub-linear expectations with applications

Classical Kolmogorov's and Rosenthal's inequalities for the maximum partial sums of random variables are basic tools for studying the strong laws of large numbers.In this paper,motived by the notion of independent and identically distributed random variables under the sub-linear expectation initiated by Peng(2008),we introduce the concept of negative dependence of random variables and establish Kolmogorov's and Rosenthal's inequalities for the maximum partial sums of negatively dependent random variables under the sub-linear expectations.As an application,we show that Kolmogorov's strong law of larger numbers holds for independent and identically distributed random variables under a continuous sub-linear expectation if and only if the corresponding Choquet integral is finite.

CHOVER'S LAW OF THE ITERATED LOGARITHM FOR NEGATIVELY ASSOCIATED SEQUENCES

Consider a sequence of negatively associated and identically distributed random variableswith the underlying distribution in the domain of attraction of a stable distribution with an exponentin(0,2).A Chover's law of the iterated logarithm is established for negatively associated randomvariables.Our results generalize and improve those on Chover's law of the iterated logarithm(LIL)type behavior previously obtained by Mikosch(1984),Vasudeva(1984),and Qi and Cheng(1996)fromthe i.i.d,case to NA sequences.

A random physical model of seismic ground motion field on local engineering site

This paper presents a random physical model of seismic ground motion field on a specific local engineering site.With this model,artificial ground motions which are consistent with realistic records at SMART-1 array on spatial correlation are synthesized.A two-scale modeling method of seismic random field is proposed.In large scale,the seismic ground motion field on bedrock surface is simplified to a two-dimensional spherical wave field based on the seismic point source and homogeneous isotropic media model.In small scale,the seismic ground motion field on the engineering site has a plane waveform.By introducing the physical models of seismic source,path and local site and considering the randomness of the basic physical parameters,the random model of seismic ground motion field is completed in a random functional form.This model is applied to simulation of the acceleration records at SMART-1 array by using the superposition method of wave group.

Quantum Correlations Evolution Asymmetry in Quantum Channels

It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entanglement and quantum discord, evolution asymmetry to various quantum channels. We found that the asymmetry of entanglement and quantum discord only occurs in some special quantum channels, and the behavior of the entanglement evolution may be quite different from the behavior of the quantum discord evolution. To quantum entanglement, in some channels it decreases monotonously with the increase of the quantum channel intensity. In some other channels, when we increase the intensity of the quantum channel, it decreases at first, then keeps zero for some time, and then rises up. To quantum discord, the evolution becomes more complex and you may find that it evolutes unsmoothly at some points. These results illustrate the strong dependence of the quantum correlations evolution on the property of the quantum channels.

Correlation Functions of an Autonomous Stochastic System with Nonlinear Time Delays

The auto-correlation function and the cross-correlation of an autonomous stochastic system with nonlinear time-delayed feedback are investigated by using the stochastic simulation method. There are prominent differences be- tween the roles of quadratic time-delayed feedback and cubic time-delayed feedback on the correlations of an autonomous stochastic system. Under quadratic time-delayed feedback, the nonlinear time delay fails to improve the noisy state of the autonomous stochastic system, the auto-correlation decreases monotonously to zero, and the cross-correlation increases monotonously to zero with the decay time. Under cubic time-delayed feedback, the nonlinear time delay can improve the noisy state of the autonomous stochastic system; the auto-correlation and the cross-correlation show periodical oscillation and attenuation, finally tending to zero with the decay time. Comparing the correlations of the system between with nonfinear time-delayed feedback and linear time-delayed feedback, we find that nonlinear time-delayed feedback lowers the correlation strength of the autonomous stochastic system.