区间模型非概率可靠性指标的一维优化算法

证明了基于区间模型的非概率可靠性指标只可能存在于:标准化区间向量张成的凸域及其扩展空间中,通过原点和凸域顶点的有限条超射线与标准化失效面的某个交点处,从而极大地缩小了优化方法求取非概率可靠性指标的可行域,使放弃计算结果极易扩张的区间运算法则和计算量太大的高维寻优方法成为可能。提出了求取非概率可靠性指标的一维优化方法,讨论了一维优化方法搜索区间关于0对称且具有半径递减的特性,利用该特性明显提高一维优化算法的效率。     

汉语缩略语规范原则(草案)

本规范(草案)将缩略语区分为缩合语、节略语和数括语。缩略语的生成除了要合乎必要性、可行性原则之外,其下属各类还应分别遵守各自的分项原则:针对缩合语的有"意义段原则"和"关联度优化原则";针对节略语的有"中心语优先原则"和"首音节优先原则";针对数括语的有"共同成分优先原则"。并存的不同缩略语可依次依据"从俗"、"从表义明确"、"从短"、"从首音节"来进行规范。缩略语的使用是否规范可根据"层次性原则""共现原则"和"得体原则"作出判断。     

Mixed norm regularized recursive total least squares for group sparse system identification

A mixed l_p,0‐regularized recursive total least squares (RTLS) algorithm is considered for group sparse system identification. Regularized recursive least squares (RLS) has been successfully applied to group sparse system identification; however, the estimation performance in regularized RLS‐based algorithms deteriorates when both input and output are contaminated by noise (the error‐in‐variables problem). We propose an l_p,0‐RTLS algorithm to handle group sparse system identification with errors‐in‐variables. The proposed algorithm is an RLS‐like solution that utilizes l_p,0‐regularization. The proposed algorithm provides excellent performance as well as reduces the required complexity by effective inversion matrix handling. Simulations demonstrate the superiority of the proposed l_p,0‐regularized RTLS for a group sparse system identification setting. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of transient multiexponential signals using exponential compensation deconvolution

A three-step procedure for the parameter estimation of transient multiexponential signals is proposed. The first step involves the use of the classical Gardner transform to convert the data signal into a convolution model which is deconvolved using exponential compensation deconvolution technique in the second step. In the third step, eigenvector algorithms are used to process the resulting complex exponentials to obtain better estimates of decay rates and number of components. Simulation and experimental results show that this method outperforms previous approaches if a number of preprocessing parameters are correctly selected.     

基于四元极谐变换矩与显著特征的图像鲁棒哈希算法

为了增强哈希序列对各种几何变换攻击的鲁棒性,设计基于四元极谐变换矩与显著特征的图像鲁棒哈希算法。引入线性插值与自适应Wiener滤波器,实现初始图像的预处理;计算预处理图像的颜色向量角度,并基于Fourier变换,得到其对应的幅度信息,以获取两个不同的频谱;计算两个频谱的残差,确定图像中的局部显著性区域;通过LBP算子,提取显著特征;基于四元极谐变换(Quaternion Polar Harmonic Transform,QPHT),获取预处理图像的QPHT矩;联合显著特征与QPHT矩,形成过渡哈希数组。引入Logistic映射,定义加密函数,实现对过渡哈希数组的加密,输出最终的哈希序列,以增强其抗碰撞性能。测量源图像与可疑图像之间的哈希序列所对应的l₂范数距离,并将其与优化阈值比较,对图像的真实性做出判断。在多种几何变换攻击下完成测试,输出数据显示:较当前准确性较高的哈希方法而言,该算法具有更理想的鲁棒性与识别准确率。     

Accounting for no difference/preference responses or ties in choice experiments

The analysis of choice data in which no difference/preference responses, or ties, occur is considered in this paper. A key issue addressed in the paper is the need for “identicality norms” for difference and preference tests. These norms reflect the researcher’s expectation for the number of ties that would have occurred in the experiment had the products tested been putatively identical. Without these norms, the issue of how to account for ties can never be fully resolved. After this idea is developed, some methods from the statistics literature to account for ties are reviewed and the Thurstonian 2-AC (2-Alternative Choice) model is discussed. Common practices of equal or proportional redistribution of ties are noted to be either conservative or liberal, respectively, when the binomial distribution is used to evaluate results. In particular, the exact probability function for the equal allocation method is given as a particular type of mixing distribution, known as a convolution, of binomial probability functions. Regardless of which statistical method is used to test tied data, however, none of the current methods of analysis can account for segmentation or the effect of heterogeneity in individual assessors. To study the possible effect of heterogeneity, the data could first be tested against an identicality norm. Thus, this research clarifies the assumptions that are made when conducting tests on paired comparison data with ties and provides guidance on the choice of analytic method.     

静压桩爆桩的原因分析与对策

根据多年的施工经验和现场调查，参考了管桩部分的规范标准，对静压桩爆桩的原因进行了分析，提出了在管桩生产和静压桩施工中应注意的问题和预防控制措施，从而确保静压桩工程的顺利进行。     

随机向量的逼近及奇异值分隔定理的应用

Ｃ．Ｒ．Ｒａｏ在［１］中都是在协方差矩阵为非奇异的情况下讨论的，作者把它们都推广到奇异的情形．作者在讨论用一个随机向且通过一个已知的随机向量中也得出一些结果，并肯定了Ｃ．Ｒ．Ｒａｏ的一个猜测．     

纸的发明与包装考

根据考古发掘的西汉初年古纸,推论造纸术可能发明于战国时代的长江流域,而非东汉时期的黄河中游地区;《考工记》中的“筐人”可能指造纸工官;古纸最初用于日常杂用包装和穿著,以后,纸质提高,方用于书写和绘图;纸包装的历史可上溯到战国时代;药丸纸包装则可上溯到汉咸帝时代(公元前32～前7年),已有2000年的悠久历史了。