Topological voiceprints for speaker identification

Despite its noninvasive nature, subject identification by voice is not as popular as other biometric procedures (i.e. fingerprinting). In part, this is due to the difficulty of establishing how close is close enough when comparing spectral features. In this work, we address this issue by showing how to characterize spectra by means of sets of integers, borrowing topological tools used in the theory of dynamical systems. On the other hand, we report an empirical result: within a relatively small bank of speakers, there are subsets of integers that seem to strenghten the speakers’ identity information. These results suggest a new direction in the identification of subjects by voice: one in which arrangements of integers define voiceprints that stand on their own, despite any acceptance/rejection thresholds.     

Extracting Work Optimally with Imprecise Measurements

Measurement and feedback allows for an external agent to extract work from a system in contact with a single thermal bath. The maximum amount of work that can be extracted in a single measurement and the corresponding feedback loop is given by the information that is acquired via the measurement, a result that manifests the close relation between information theory and stochastic thermodynamics. In this paper, we show how to reversibly confine a Brownian particle in an optical tweezer potential and then extract the corresponding increase of the free energy as work. By repeatedly tracking the position of the particle and modifying the potential accordingly, we can extract work optimally, even with a high degree of inaccuracy in the measurements.     

一个二次多项式混沌系统的均匀化及其熵分析

利用已有理论给出了一个二次多项式混沌系统,证明了该系统与Tent映射拓扑共轭,给出了该混沌系统的概率密度函数;并根据此概率密度函数,得到了轨道均匀分布的反三角函数映射;对均匀化前后的混沌系统在不同参数下产生序列的信息熵、Kolmogorov熵、离散熵的特性进行了分析,结果显示均匀化后产生的混沌序列混沌程度不改变且具有更好的均匀性.     

Information,information gain,and efficiency of self-organizing systems close to instability points

Selforganizing systems are those which can acquire macroscopic spatial, temporal, or spatio-temporal structures without interference from the outside by mere changes of control parameters. The slaving principle which has been derived for such systems close to their instability points allows one to give the probability distribution of the total system a specific form.This in turn allows one to decompose information and information gain into a part which refers to the order parameters alone and a second part which is a sum over the information of the slaved modes averaged over the distribution of the order parameters. Close to instability points the information of the order parameters changes dramatically whereas the information of the slaved modes does not. Therefore close to these points it is sufficient to study the behavior of the order parameter information and information gain which is done explicitly for a large class of systems undergoing nonequilibrium phase transitions. It is shown how information and information gain as well as efficiency (in the sense defined in this paper) can be measured directly.     

原子力显微镜高次谐波幅度对样品弹性性质表征的研究

轻敲模式下原子力显微镜微悬臂探针在接近其基态共振频率的外加驱动下振荡, 其末端针尖周期性靠近、远离样品, 产生于针尖与样品非线性相互作用过程中的高次谐波信号包含更多的待测样品表面纳米力学特性等方面的信息. 通过理论分析、计算, 系统地研究了针尖与样品接触时间受样品弹性模量的影响, 以及高次谐波幅度与接触时间的关系, 获得了通过高次谐波幅度区分待测样品表面弹性性质差异的规律. 并在自制的高次谐波成像实验装置上, 得到了与理论预期一致的实验结果. 关键词： 轻敲模式原子力显微镜 接触时间 高次谐波幅度 弹性模量     

Experimental study of the spectral anomalies in Young’s interference experiment

We report, the experimental result of a study, conducted to investigate the spectral anomalies in the region of superposition in the Young’s double-slit interference experiment. These results are in close agreement with the theoretical study by Pu et al. (J. Pu, C. Cai S. Nemoto, Opt. Express 12 (2004) 5131). The application of this study might be useful in realizing the information transmission in free space, in optical signal processing and optical computing.     

户外聚光测试系统设计

为了提高聚光系统的聚光效率,设计了一种户外聚光测试系统.选二阶菲涅耳聚光系统为测试对象,采用局部测量法测试其性能.利用软件模拟聚光系统的透过率、聚光效率和聚光光斑照度分布,并利用户外聚光测试系统对二阶菲涅耳聚光系统进行实验测试.将模拟结果与实验结果对比发现:二者的光斑分布均匀性比较接近,透过率相差1.800%|聚光效率相差4.346%,主要差异来源于加工误差和测量误差.据此可以为设计和加工提供信息反馈,从而改进加工工艺,提高聚光效率.     

腔内混合态原子系统中辐射场的压缩效应

本文应用熵最大原理，假定腔内二能级原子起初就没有关于系统所处态的任何信息，研究了腔内原子与腔场相互作用的压缩行为，得出了原子初始处于任意统计混合态下，当初始激发足够强时，辐射场将产生极其接近于纯态情况在相同激发时的强压缩现象的重要结果，同时还讨论了产生压缩的混态范围。     

一种基于修正扩展形态学算子的高光谱遥感图像端元提取算法

形态学算子反映了像素的空间相关性信息,将其应用于高光谱遥感图像端元提取可以有效地提升算法性能,本文针对已经普遍用于高光谱遥感图像端元提取的扩展形态学算子在像元排序规则和替换准则上存在的局限性,引入了基准向量的概念并给出计算方法,提出了修正扩展形态学算子.修正后的排序规则和替换准则避免了图像中不同类别交界处的交叉替换现象,保证了正确的覆盖方向,是提高端元提取效果的关键步骤.通过修正扩展形态学算子的基本膨胀和腐蚀运算,定义了相应的开-闭运算和闭-开运算,由此得出了端元判定向量,并给出端元提取算法的详细流程.基于扩展形态学的自动端元提取算法可以综合考虑光谱和空间信息,端元提取效果优于仅依靠光谱信息的算法.算法由IDL7.0实现,并在AVIRIS于Cupritc地区的高光谱遥感图像上进行实验,实验结果从光谱曲线相似性、端元平均相似度和相应地物分布图等方面证明了算法的有效性.     

LIBS与反向传播算法结合的橄榄石成分分析

LIBS是一项用于分析物质成分的有力手段，但是定量分析时存在结果不准确、重复性低等缺点。为了准确预测自然界中橄榄石的成分信息，通过按照自然界中的橄榄石的成分信息制作15组橄榄石样品，将其中的11组作为标准样品，另外4组作为测试样品进行LIBS定量分析。每个样本采50条LIBS光谱建立橄榄石的LIBS数据库。然后采用多元线性回归算法和反向传播算法对样本的50组数据进行分析，有效的降低了由于随机误差造成的测试结果的不准确。最终结果表明，使用激光诱导击穿光谱和反向传播算法对橄榄石中镁橄榄石与铁橄榄石含量进行检测，预测结果的决定系数为0.901，接近常规的多元线性回归算法得到的0.911，这说明反向传播算法对橄榄石含量的预测精度接近多元线性回归算法。同时使用反向传播算法得到的结果的均方根误差为28.64，优于后者的29.23，说明使用反向传播算法得到的结果分布更加集中。此外，通过分析关联矩阵中各数值的大小与各元素谱线的位置的对应关系，表明使用反向传播算法反演出来的关联矩阵F与之所代表的物理含义的相关性更高。说明反向传播运算不仅与传统的多元线性回归算法性能相当，而且在预测数据的一致性上表现得更好。此外使用反向传播算法可以直接对激光诱导击穿光谱得到的橄榄石全谱数据进行数据反演，而不需要经过光谱寻峰这一步骤，简化了数据分析流程，弥补了多元线性回归算法难以分析全谱数据的不足。     

多种图像采集策略下X射线折射信息的提取研究

不同的图像采集策略下,基于分析晶体相衬成像技术的折射信息提取方法(衍射增强成像法、广义衍射增强成像法、多图成像法)的折射角提取结果有明显的差异.与摇摆曲线腰位作为图像采集位置的传统策略相比,采集位置靠近摇摆曲线中轴时,衍射增强成像法能够提取得到更好的折射角结果.广义衍射增强成像法的三个图像采集位置相对摇摆曲线中轴对称时,折射角的提取结果好于采集位置非对称的结果,并且采集位置靠近摇摆曲线中轴时,折射角的提取结果好于摇摆曲线腰位或趾位的结果.对于多图成像法,相邻图像采集位置的角度间隔大于摇摆曲线半高全宽时,折射角提取结果非常差;而当角度间隔小于半高全宽并且图像采集位置对应的角度范围接近样品的最大折射角理论值时,能够获得很好的折射角提取结果.此研究有助于实验上对图像采集策略的合理选择以及对折射信息提取方法的更深理解.     

变焦距镜头组的自适应调焦的实现

介绍了ST16160自动调光变焦镜头,在无距离信息情况下实现自适应调焦的方法并做了相应的实验实验采用图像处理技术实现自适应调焦,用图像采集卡采集视频信号在内存中存成一幅图像,运用图像处理学中的锐化技术对采集到内存中的图像进行处理,锐化采用梯度运算,以梯度运算得到的结果作为检测和评估焦面是否合适的标准,结果表明对静态近目标和远目标的自适应调焦有良好的调焦效果,运用图像处理方法寻找成像清晰的位置准确可靠.     

一种改进的基于信息传播率的复杂网络影响力评估算法

评价网络中节点的信息传播影响力对于理解网络结构与网络功能具有重要意义.目前,许多基于最短路径的指标,如接近中心性、介数中心性以及半局部(SP)指标等相继用于评价节点传播影响力.最短路径表示节点间信息传播途径始终选择最优方式,然而实际上网络间的信息传播过程更类似于随机游走,信息的传播途径可以是节点间的任一可达路径,在集聚系数高的网络中,节点的局部高聚簇性有利于信息的有效扩散,若只考虑信息按最优传播方式即最短路径传播,则会低估节点信息传播的能力,从而降低节点影响力的排序精度.综合考虑节点与三步内邻居间的有效可达路径以及信息传播率,提出了一种SP指标的改进算法,即ASP算法.在多个经典的实际网络和人工网络上利用SIR模型对传播过程进行仿真,结果表明ASP指标与度指标、核数指标、接近中心性指标、介数中心性指标以及SP指标相比,可以更精确地对节点传播影响力进行排序.     

Light-charged particle emission in fission

The emission of light charged particles in the fission process is of interest as they are believed to emerge from the neck region of the deformed fissioning nucleus at a time close to the scission point and may thus prove a useful probe to investigate the last stages of fission close to the rupture point. Experimental results on light charged particle emission and the efforts made to obtain information about the scission point parameters therefrom are reviewed.     

Critical behavior of nanoemitter radiation in a percolation material

We studied the field radiation of disordered optical nanoemitters incorporated into three-dimensional (3D) spanning cluster in a percolation material. In supercritical state, the field intensity is large enough to produce a dynamic high-density coherent field. The resulting state becomes different for lossless and lossy mediums. For material with small losses the long-term coherence arises in the supercritical area close to the percolation threshold. As a result, the dynamic non-monotonic behavior of the field order parameter raises that allows to reach the optimal field intensity. This effect can allow optimization of the disordered optical nanostructures with incorporated radiating nanoemitters in various applications of information technology.     

Einstein-Podolsky-Rosen Steering and Quantum Phase Transition in Spin Chains

We study the Einstein-Podolsky-Rosen steering and quantum phase transitions of the transverse Ising and antiferromagnetic XXZ spin-1/2 chains. By making use of steerable weight, we calculate the steerability for the bipartite subsystems of the models. It is shown that steerability vanishes abruptly and its value maintains zero in a region close to the critical point for the Ising chain. This result is quite different from the information provided by entanglement and quantum discord. While for the XXZ chain, steerability increases and reaches maximal at the critical point, indicating the occurrence of quantum phase transition.     

The multipole particle and the Papapetrou equation

The conclusion is made that the supplementary conditions of Pirani, Dixon, or others, which close the system of dipole equations of the general theory of relativity for a test particle and as a result make it possible to uniquely calculate the motion of such a particle, in essence determine the internal structure of the particle. The conclusion is made against the background of the solution of the problem of the multipole expansion of the tensor density along a line and a multipole formulation of the equations of motion of a body. It is shown that the Papapetrou equations can be employed to calculate the behavior of particles only if information contained in the dipole equations is used.S. Ordzhonokidze Aeronautical Institute, Moscow. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 43–48, October, 1994.     

The focusing performance with a horizontal time- reversal array at different depths in shallow water

The performance of time-reversal focusing with a horizontal line array at different depths is investigated by normal mode modeling and computer simulation.It is observed that the focusing performance of a bottom-mounted horizontal time-reversal array is much better than that of a horizontal time-reversal array at other depths in shallow water.The normal mode modeling is used to explain this result.The absolute values of the modes at different depths are compared.It is shown that the number of modes whose absolute values close to zero is smaller at the bottom than that at other depths.It means that the horizontal time-reversal array deployed at the bottom can sample more modes,obtain more information of the probe source and achieve better focusing performance.The numerical simulations of time-reversal focusing performance under various conditions,such as different sound speed profiles,and different bottom parameters,lead to similar results.     

Virial theorem for localized states of a quantum particle in classical fluids close to the critical point

Localized states of a light quantum particle, thermalized in a dense classical fluid close to the critical point, obey a simple virial identity as a result of the scaling properties of the host medium. This identity may serve as a self-consistency check for coarse-grained theories of localization.