基于HHT方法的爆破地震信号分析

在介绍HHT(Hilbert HuangTransform)理论的基础上,结合现场测试,将这种理论引入到爆破地震信号分析中。HHT方法主要通过经验模式分解方法将信号分解成有限的固有模态函数,并对每个固有模态函数进行Hilbert变换从而得到Hilbert谱。经过FFT、小波谱对比分析,结果表明:在爆破地震信号分析中,利用经验模式分解不需要固定的基函数,可将原始信号分解为少量的、频率自高至低排列的固有模态函数,分解过程具有自适应性、高效性;再通过Hilbert变换所得的谱图能清晰地反映原始地震信号能量随时间、频率的分布。HHT法能有效地提取爆破地震信号的主要特征,更能适应信号突变快、衰减快的特征,为进一步认识爆破地震波的传播机理、破坏原因和危害判据的确定提供了新的途径。     

Hilbert空间在量子力学中的应用

本文讨论了量子力学与Ｈｉｌｂｅｒｔ空间的关系,以及Ｈｉｂｅｒ空间在量子力学中的应用。     

Forensic Architecture

The urban destruction captured by black and white photos of London after the Blitz or bomb-damaged Berlin are emblematic of the desolation brought by modern warfare. Eyal Weizman , Paulo Tavares , Susan Schuppli and Situ Studio describe, though, how the built environment now represents more than a means of violation in conflict, as it has become an important source of evidence bearing witness to the event when international justice is sought. Copyright © 2010 John Wiley & Sons, Ltd.     

Adaptive Fourier Series and the Analysis of Periodicities in Time Series Data

A Fourier series decomposes a function x ( t ) into a sum of periodic components that have sinusoidal shapes. This paper describes an adaptive Fourier series where the periodic components of x ( t ) may have a variety of differing shapes. The periodic shapes are adaptive since they depend on the function x ( t ) and the period. The results, which extend both Fourier analysis and Walsh–Fourier analysis, are applied to investigate the shapes of periodic components in time series data sets.     

Orlicz空间几何学研究在哈尔滨(英)

综合评述哈尔滨泛函学派在近15年里关于Orlicz空间几何学的研究工作。     

Anxiety and the Archive: Understanding Plagiarism Detection Services as Digital Archives

Based on a case study of the popular plagiarism detection service Turnitin, particularly its “Legal Document,” this article contends that plagiarism detection services should be viewed as digital archives. Services like Turnitin not only seek to regulate what constitute original texts and appropriate writing practices but also to advance conceptions of the work that archives should do in storing and circulating texts in digital spaces. This article concludes that the services we sometimes use to ensure the integrity of students’ texts can themselves be of questionable integrity—largely through the design of their archives. As increasing numbers of texts take digital form, the problems and promise of digital archives will demand thoughtful responses that do not rush to replace questionable writing and research practices with equally troubling pedagogical and archival ones. These thoughtful responses start with exploring the use of plagiarism detection service archival technology in unadvertised ways.     

基于改进HHT的双电机消隙状态动态定量评价技术

双电机消隙这一技术的引入为重型数控机床进给系统的高精度传动提供了一种可靠的解决方案。针对目前双电机消隙动态定量效果评价方法缺乏的问题,提出了基于改进HHT的双电机消隙进给系统消隙状态定量识别技术。以进给系统电流变化作为检测技术,实现在不干扰生产的同时获得高信噪比的测试信号。以EEMD和Hilbert局部能量谱对传统HHT进行改进并作为电机电流信号处理技术,解决了电流信息的非平稳和非高斯分布问题,实现了对双电机消隙的消隙状态进行定量化识别。仿真和实验验证了该方法的有效性。     

Orlicz序列空间的k—端点,k—光滑点

给出了Ｏｒｌｉｃｚ序列空间ｌ（Ｍ）的ｋ－端点、ｋ－光滑点的判据，同时得到了ｌ（Ｍ）是ｋ－严格凸、ｋ－光滑空间的充要条件。     

Fixed Queries Array: A Fast and Economical Data Structure for Proximity Searching

Pivot-based algorithms are effective tools for proximity searching in metric spaces. They allow trading space overhead for number of distance evaluations performed at query time. With additional search structures (that pose extra space overhead) they can also reduce the amount of side computations. We introduce a new data structure, the Fixed Queries Array (FQA), whose novelties are (1) it permits sublinear extra CPU time without any extra data structure; (2) it permits trading number of pivots for their precision so as to make better use of the available memory. We show experimentally that the FQA is an efficient tool to search in metric spaces and that it compares favorably against other state of the art approaches. Its simplicity converts it into a simple yet effective tool for practitioners seeking for a black-box method to plug in their applications.     

凸度量空间内广义渐近拟非扩张映射不动点的迭代

在凸度量空间中，引入一类比渐近拟非扩张映射更加广泛的广义渐近拟非扩张型映射，并在完备凸度量空间给出修改的Ishikawa迭代序列收敛于广义渐近拟非扩张型映射不动点的充要条件。