改善安全工作的对策

安全是铁路运输生产的头等大事。应严格落实安全规章制度；改善安全设施，加强安全教育，加强干部管理，有效地控制人身伤害事故的发生。     

基于正交小波变换的计权声级测量

提出了采用正交小波变换进行计权声级测量的方法 ,克服了传统计权声级测量系统中采用模拟计权网络的缺点 ,比采用短时傅里叶变换方法更能反映人耳对噪声的主观感觉特性。理论分析和仿真计算表明 ,该方法是可行的。为了进一步提高计算精度和减少计算复杂度 ,给出了对应于 IIR滤波器的正交小波变换、自适应小波包变换和匹配小波变换等三种可能的改进方法。     

300 t转炉IF钢低枪位低终点氧冶炼工艺实践

在脱磷理论分析基础上,采用低枪位冶炼和低终点氧出钢,增大出钢口直径和降低终点温度,并优化底吹工艺降低碳氧积,取得了较好的脱磷效果。生产应用结果表明:采用增大出钢口和优化底吹工艺后,300t转炉出钢时间缩短至5.1 min,缩短了1.9 min;IF钢终点温度降低至1 670.6℃,降低了17.4℃;碳氧积降低至13.3,降低了8.9;终点氧降低至422.5×10^-6。在铁水磷升高0.010%,枪位降低30 cm,终点氧降低153.3×10^-6的条件下,工艺优化后的平均终点磷含量为0.012 4%,能够满足转炉冶炼IF钢对脱磷效果的要求。     

IDENTIFICATION OF DIESEL FRONT SOUND SOURCE BASED ON CONTINUOUS WAVELET TRANSFORM

Acoustic signals from diesel engines not only colitain useful information but also includeconsiderable noise components. To extract information for condition monitoring purposes the continu-ous wavelet transform (CWT)is used for the characterization of engine acoustics. The charasteristicsof the CWT in terms of the representation of short duration transient signals are reviewed firstlyWavelet selection and CWT implementation are then detailed. With the wavelet transform, the majorsoures of the exterior radiation sound of the engine front are surveyed. The research provides a reli-able basis for engineering practice to reduce vehicle sound level. Furthermore, the idenification resultsof the measured acoustic signals are compared with the identification results of the measured surfacevibration, and good agreement is observed.     

Determination of Relaxation Moduli and Poisson‘s Ratio in Uniaxially Loaded Solid Polyethylene Foam Specimens as Part of Full Material Characterization

The mechanical behavior of a solid polyethylene foam is characterizedby a constitutive equation which is of second order in the linearstrain tensor. It turns out that for the determination of the sixtime dependent material functions relaxation tests intension/compression, torsion and, for instance, in isotropic tension andcompression are necessary. For tension/compression tests theexperimental procedure is described in detail. Main emphasis is givento the methods of optical deformation measurement techniques. Resultsfor the relaxation moduli in tension/compression and for the Poissonsratio are presented.     

PUseqClust:一种RNA-seq数据聚类分析方法

基因的聚类分析是基因表达数据分析研究的重要技术,它按照表达谱相近原则将基因表达数据归类,探究未知的基因功能.近年来,RNA-seq技术广泛应用于测量基因表达水平,产生了大量的读段数据,为基因表达聚类分析提供了充分条件.由于读段非均匀分布的特性,对读段计数一般采用负二项分布进行建模.现有的负二项分布算法和传统的聚类算法对于聚类分析都是直接对读段计数进行建模,没有充分考虑实验本身存在的各种噪声,以及基因表达水平测量的不确定性,或者对聚类中心的不确定性考虑不够.基于PGSeq模型,模拟读段的随机产生过程,采用拉普拉斯方法考虑多条件多重复基因表达水平之间的相关性,获得了基因表达水平的不确定性,联合混合t分布聚类模型,提出PUseqClust （propagating uncertainty into RNA-seq clustering）框架进行RNA-seq读段数据的聚类分析.实验结果表明,该方法相比其他方法获得了更具生物意义的聚类结果.     

基于特征值的黑盒子意义下的特殊门限秘密共享方案

摘 要: 基于Shamir(n,t)秘密共享方案,提出一个新的门限秘密共享方案。利用n阶矩阵的特征方程具有重根的特点,实现了不同集合中参与者的秘密共享。同一参与集合所对应的次主密钥是相同的,即特征值是相同的,将同一个特征值所对应的不同特征向量作为子密钥,分发给同一参与集合的参与成员。而且,利用黑盒子,同一集合内部成员可以验证自己手中的子密钥的真实性,从而达到了防欺诈的目的。分析结果表明,本方案是安全的理想秘密共享方案。     

标准模型下完美前向安全的基于身份认证密钥交换

一轮Diffie-Hellman密钥交换(One-Round Diff ie-Hellman key exchange,OR-DHKE)协议被认为无法实现完美的前向安全性(Perfect Forward Secrecy,PFS)。基于身份的OR-DHKE协议也是如此,现有研究仅实现了弱的完美 前向安全性(wPFS)。基于Cremers等人对密钥交换协议完美前向安全性的研究,文章提出 一种新的具有完美前向安全的基于身份认证密钥交换方案。文章首先提出一种较弱安全性的 基于身份 OR-DHKE协议π₀,然后采用Cremers等人提出的SIG变换方法,将π₀转化为具有完美前 向安全的基于身份认 证密钥交换方案π₁。文章简要分析了CK、CK⁺、eCK和eCK-PFS安全模型的异同,在此 基 础上定义了基于身 份认证密钥交换协议分析的强安全模型ID-eCK-PFS。在ID-eCK-PFS模型下,协议π₀和π₁的安全性被规约为 求解判定性BDH(Decisional Bilinear Diffie-Hellman,DBDH)问题,规约过程未使用随 机预言机,实现了在标准模型下的完美前向安全性和可证明安全性。     

针对集客厚覆盖项目降本增效的研究

本文针对运营商提出的降本增效行动,统计某地市各批次集客厚覆盖工程数据,通过分析数据发现问题,并结合实例分析对比,有针对性的对独立政企和聚类市场两类场景下的设计方案进行优化和改进,达到降本增效目的。     

Wavelet multi-resolution analysis on particle dynamics in a horizontal pneumatic conveying

The particle velocities are measured by the high-speed particle image velocimetry (PIV) in the acceleration and fully developed regimes of a horizontal pneumatic conveying. Based on the measured particle fluctuation velocities, continuous wavelet transform and one-dimensional orthogonal wavelet decomposition were applied to reveal particle dynamics in terms of time frequency analysis, the contribution from wavelet level to the particle fluctuation energy, spatial correlation and probability distribution of wavelet levels. The time frequency characteristics of particle fluctuation velocity suggest that the small-scale particle motions are suppressed and tend to transfer into large scale particle motions from acceleration regime to fully developed regime. In the near bottom part of pipe, the fluctuation energy of axial particle motion is mainly contributed from the wavelet levels of relatively low frequency, however, in the near top part of pipe, wavelet levels of relatively high frequency make comparable contribution to the axial particle fluctuation energy in the suspension flow regime, and this contribution decreases as particles are accelerated along the pipe. The low frequency wavelet levels exhibit large spatial correlation, and this spatial correlation increases as the particles flow from acceleration regime to fully developed regime. The skewness factor and kurtosis factor of wavelet level suggest that the deviation of Gaussian probability distribution is associated with the central frequency of wavelet level, and the deviation from Gaussian distribution is more evident as increasing central frequency. The higher wavelet levels can be linked to small sale particle motions, which lead to irregular particle fluctuation velocity.