A design for a general digital filter for state estimation of an arbitrary stochastic sound system

This article describes a new attempt at the design of a general digital filter for the state estimation of a nonstationary nonlinear stochastic sound system. A recursive algorithm for estimating the higher-order statistics of arbitrary-function type, mean, and variance is obtained by introducing a new expansion form of Bayes' theorem. Further, the state probability density function (PDF) can also be estimated in a unified form of orthogonal or nonorthogonal series expansions by using these estimates. This method is widely applicable for cases where the random-noise fluctuation is non-Gaussian. The estimation algorithm proposed in this article agrees completely with a well-known Kalman filtering theory [J. Basic Eng. 82, 35-45 (1960); Kalman and Buchy, J. Basic Eng. 83, 95-108 (1961)], as a simplified special case when the stochastic system is of linear type with Gaussian random excitation. The validity and effectiveness of the proposed theory were confirmed experimentally by applying it to actually observed room acoustic data and road-traffic noise data.     

A new approach to a practical subwavelength resolving microscope

Superresolution depends on near-field capture and transfer of high spatial frequencies from the scattering object. These evanescent waves are transferred to a near-field image domain using a negative index material. Measuring images with subwavelength scale resolution in the near field by scanning is not practical and ignores inevitable object–lens–image coupling phenomena as well as the need to employ inverse scattering algorithms. An alternative approach based on compressive sampling permits the use of a single fixed detector. Traditionally, in such a system, an image-bearing wavefront is projected onto a series of patterns (= basis functions) and the transmitted light integrated by a lens onto a single-point detector. Image reconstruction is possible by weighting each basis function with its measured coefficient and summing, including basis functions representing evanescent waves. We employ a single fixed detector in the back focal plane of a negative index concave lens and basis functions realized by structured illumination from combinations of a set of discrete sources. We have investigated this as an approach to recover subwavelength scale details about a scattering object and report our results.     

自调整平滑区间粒子滤波平滑算法

针对非线性系统的状态估计问题, 提出了一种自调整平滑区间粒子滤波平滑算法. 该算法的显著特点是根据采样粒子观测值与系统状态观测值之间的偏差动态修正滤波平滑区间的长度, 有效抑制了传统的粒子滤波平滑算法中因区间长度固定可能造成粒子权重重新赋值带来误差增大的问题. 该算法的原理是依据粒子滤波器的工作机理, 把系统状态信息和热槽组成一个抽象的整体, 将粒子滤波平滑过程类比为观测信息和热槽交互的统计力学系统. 在无新的观测信息时, 整个系统遵循热力学第二定律, 即无论从任何初始状态出发, 整个力学系统的熵是非减的; 而当出现新的观测信息时, 粒子滤波器像麦克斯韦妖从新的观测信息中抽取能量传送给热槽, 使整个抽象系统的熵减少, 根据系统熵的递变规律变化对滤波平滑区间的长度加以动态修正, 优化粒子的权重赋值, 进而提高系统状态的估计精度. 利用matlab进行了仿真分析, 验证了该算法的有效性.     

A new system for rating impact sound insulation

The rating of impact sound insulation on the basis of tapping machine measurements with the ISO reference values has proved to be unsatisfactory in practice. This is mainly due to the differences in spectrum shape of tapping machine noise and real life impact noises, such as walking. The problem can be solved by changing the reference values in accordance with these differences in spectrum shape. The difference between tapping and walking noise spectra has been established by measurements on 49 different floors. In the most important frequency range (125–500 Hz) it was discovered to be sufficiently constant for all the floor constructions considered.Thus a new set of reference values has been derived, based on the assumption that the NR-curves provide a correct subjective rating system for walking noise.In addition, due account has been taken of the different frequency content at higher frequencies of impact noises other than those made by walking males, such as those made by walking females, jumping children, the moving of furniture, etc.     

An equation of state and non-linear parameter from sound velocity measurements for liquid alkali metals

In the present paper, an equation of state has been obtained in case of liquid alkali metals like Na, K, Rb and Cs from sound velocity measurements. The theory developed gives very good agreement for both the sound velocity and the volume as a function of pressure at different temperatures in these liquid alkali metals. Further, the variation of non-linear parameter,B / A, as a function of pressure and temperature is also studied.     

Event-based state estimation for a class of complex networks with time-varying delays: A comparison principle approach

The paper is concerned with the state estimation problem for a class of time-delayed complex networks with event-triggering communication protocol. A novel event generator function, which is dependent not only on the measurement output but also on a predefined positive constant, is proposed with hope to reduce the communication burden. A new concept of exponentially ultimate boundedness is provided to quantify the estimation performance. By means of the comparison principle, some sufficient conditions are obtained to guarantee that the estimation error is exponentially ultimately bounded, and then the estimator gains are obtained in terms of the solution of certain matrix inequalities. Furthermore, a rigorous proof is proposed to show that the designed triggering condition is free of the Zeno behavior. Finally, a numerical example is given to illustrate the effectiveness of the proposed event-based estimator.     

A new approach for the estimation of the axial velocity using ultrasound

The most used estimation method for calculating the blood velocity in commercial scanners is the autocorrelation approach. The calculation of the mean velocity used in this method depends on the center frequency of the interacting ultrasound pulse which downshifts as a function of depth, introducing a bias. A new velocity estimator for the mean axial velocity is presented. The estimation principle is based on the 2D Fourier transform and the Radon transform. The input data are a sequence of RF data forming a 2D data input, one column for each pulse emission. A 2D segment is selected for a specific depth. This data segment is first transformed by a 2D Fourier transform, and the result is then transformed by a Radon transform. The center of gravity for the angles of the lines intersecting the origin of the R-theta coordinate system in the Radon domain gives the mean axial velocity for the data segment. The benefit of this method is an estimate of the mean axial velocity which is independent of the center frequency of the propagating ultrasound pulse. The estimate will only depend on f(s) and f(pr f). Results of the estimation method is presented based on both simple generated RF harmonic data for different signal/noise ratios and simulated acoustic RF responses from a 3D measurement situation with an array transducer and a tube with plug flow. The new method shows improvement with a factor of 1.5-4 on the standard deviation on the estimated mean velocity for the simulated case.     

一类新混沌系统的线性状态反馈控制

研究了一类新混沌系统的控制问题.利用Routh-Hurwitz准则对受控系统进行了稳定性分析，结合线性状态反馈方法理论上严格证明了达到控制目标反馈系数的选择原则.数值研究证明了该方法能够有效地控制混沌系统到失稳的平衡点或周期解，同时控制效果在弱噪声干扰下具有很强的鲁棒性. 关键词： 新混沌系统 线性状态反馈控制 Routh-Hurwitz准则 噪声     

A new approach to irreversibility from maximum entropy estimation

This paper deals with the study of some irreversible processes like slow heating of a thermodynamic system or of inhomogeneity, i.e. spatially local equilibrium in it, based on the principle of maximum entropy estimation, in a stochastic model.     

A FRW dark fluid with a non-linear inhomogeneous equation of state

A dark Friedman–Robertson–Walker fluid governed by a non-linear inhomogeneous equation of state is considered that can be viewed as a conveniently simple paradigm for a whole class of models that exhibit phase transitions from a non-phantom towards a phantom era (superacceleration transition). On the other hand, such dark fluid models may also describe quintessence-like cosmic acceleration. Thermodynamical considerations for the processes involved, which are of great importance in the characterization of the global evolution of the corresponding universe, are given too. Connecting the proposed equation of state with an anisotropic Kasner universe with viscosity, we are led to the plausible conjecture of a dark fluid origin of the anisotropies in the early universe.     

A new approach to the properties of a harmonic crystal in a stationary nonequilibrium state

An exact analytical solution has been obtained for the covariance matrix resulting from a stochastic interaction of a linear chain ofN coupled harmonic oscillators with different heat reservoirs via its endparticles. For the special case, that the friction forces on the endparticles, which result from the system-heatbath-interaction, are equal, we obtain the same results as Lebowitz et al. by applying an entirely different mathematical technique as these authors have used. For the realistic coupling, where friction and diffusion coefficient differ for different heatbaths and are only connected via the Einstein relation we obtain additional contributions to the correlation matrices between the momenta and between the displacements.On leave from the School of Nuclear Engineering, The University of New South Wales, Sydney, Australia     

A new approach of binary addition and subtraction by non-linear material based switching technique

Here, we refer a new proposal of binary addition as well as subtraction in all-optical domain by exploitation of proper non-linear material-based switching technique. In this communication, the authors extend this technique for both adder and subtractor accommodating the spatial input encoding system.     

一种基于遗传算法的混沌系统参数估计方法

通过构造一个适当的适应度函数,将混沌系统的参数估计问题转化为一个参数的寻优问题,然后利用遗传算法的全局优化搜索能力对其进行求解.以典型的Lorenz混沌系统为例进行了数值模拟.实际数值模拟表明,使用这种方法可以有效地对混沌系统的参数进行估计 关键词： 混沌系统 参数估计 遗传算法     

A new method for generating nonclassical correlation state of the light in a open-loop LED system

The nonclassical correlation state of the light have been investigated experimentally in re-cent years.After the open-type amplitude squeezed state of the light has been observed experi-mentally,we have generated and observed nonclassical correlation state of the light deep sup-pression in a open-loop LED system with very simple setup.The experimental apparatus isshown in Fig.1.In which,a closed-loop Ch1 is consist of LED1,PD1,A1,A3 and low-noise     

一种新的声速推导方法

利用动量定理给出一个简单而又直观的推导气体中声速的方法。     

A global analysis of a non-linear system under parametric excitation

A strongly non-linear mechanical system consisting of a rigid damped bar subjected to a periodic parametric excitation is treated here in an exact manner. The emphasis is on the global behavior of this system which is carried out by using the point mapping and the cell-to-cell mapping methods. Even though the mechanical system is a simple one, yet it has a very complex global behavior. It is shown here that the newly developed theory of cell-to-cell mappings offers a tremendous advantage in obtaining the global domains of attraction of strongly non-linear dynamical systems.     

A numerical study of steady state non-linear heat flow in a Lorentz plasma

Steady state heat flow in a Lorentz plasma is investigated using a discrete ordinate method. The model problem which is studied is the calculation of the heat flow between two boundaries at which the inward flowing part of the distribution function is half maxwellian and between which there is a constant ion density and zero current. Results agree with the appropriate collisionless and collision dominated limits.