荧光寿命的快速傅里叶变换拟合方法

介绍了一种利用快速傅里叶变换算法对稀土掺杂物质的荧光寿命进行数据拟合的方法。稀土掺杂物质可用来制备多种光学传感器,用于温度、pH值等多种参量测量领域。本方法利用快速傅里叶变换(FFT)结果作为基础,从非零项的相位角的正切值得出被测的荧光寿命,具有速度快、误差小、不受本底干扰等一系列优点。以掺铒光纤为例,通过数字仿真将本方法与其它几种传统的拟合方法进行了比较。快速傅里叶变换方法的测量偏差不到Prony方法的50％,为对数似合(log-fit)方法测量偏差的1／6。另外,快速傅里叶变换方法由于不受本底噪声影响,可以不必在信号处理时去掉本底噪声,因而可以明显缩短测量时间。     

长基线声学定位系统跟踪解算优化方法

针对现有长基线定位解算算法忽略阵型标定误差的问题,本文提出了一种结合声信标的标定误差和测距误差的待定目标解算方法。该方法利用观测数据的先验误差将观测数据连同带求解量一并构建平差解算模型,可以对待定目标位置解算进行优化求解。采用该方法对现有测量船只的跟踪定位实验进行数据处理,得到的跟踪定位轨迹平滑连续,和传统方法相比更接近于GPS输出结果,在深水环境下效果提升明显。理论分析和实验结果表明采用该方法能够获得更优化的位置估计结果及全局误差,能够应用于高精度长基线定位系统中。      

用代数多重网格法求解一维分裂格式的Euler方程

提出了代数多重网格法(AMG)的一种新算法。新算法改进了插值公式和粗网格方程,并把它应用到求解一维的分裂格式Euler方程。数值结果表明,对于具有高CFL条件数的Euler方程,代数多重网格法可以求解;对于Gaus-Seidel方法求解不能收敛的代数方程组,代数多重网格法求解可以收敛。新算法改进了代数多重网格法的收敛性和扩展了它的应用范围,数值结果表明了它的有效性和强壮性。     

运动声源快速定位的声达时差法

针对声达时差法只能用于非运动声源定位的问题,本文提出一种运动声源快速定位方法。该方法以声达时差为基本定位原理,基于声源计算位置对多普勒效应进行解耦并进行声信号多普勒效应修正,根据三角定位方法构建声传播空间矩阵,以声源位置偏差度为目标基于单纯形优化搜索算法进行声源位置快速逼近,实现了对匀速直线运动的单声源的定位追踪,提高定位实时性。该方法将声达时差法拓展到运动声源的定位,同时解决了消除多普勒效应带来的计算过程复杂、运算量大的问题,仅用4个传声器就可实现运动声源的快速定位,突破了传统运动声源识别中对大传声器阵列的依赖。仿真实验和实车运动声源识别实验结果证明了该方法的有效性,本研究为短时发声运动声源的识别提供了一种简便、高效的方法。      

原子吸收法间接测定泥炭水解物中的还原糖

本文研究是在常规分析基础上，提出的原子吸收法间接测定泥炭水解物中还原糖的方法。并探讨了方法中酸性介质、共存元素的影响等问题。本方法与常规方法比较，具有测定速度快，试剂用量少，准确性、重现性高等优点。     

Prediction condensed models adapted to the nonlinear structures in time domain

This paper deals with a method to study closely the stationary solution of nonlinear dynamic systems in time domain. This method is based on the exploitation of Karhunen-Loève decomposition with or without parametric modifications as well as on the characteristics of localized nonlinearities. With the application of this method at first on linear models initially condensed by Karhunen-Loève, the predictions of nonlinear responses can be obtained rapidly. This method is adapted to a condensed linear model used in the first optimization procedure of the nonlinear dynamic behaviour. This robust basis will be used as condensation basis of the modified model local per zone, which leads to a prediction of vibratory responses of complex structures modified and affected by localized nonlinearities.     

霍尔传感器法测量金属线胀系数

介绍了一种新颖的金属线胀系数测量方法,该方法是利用霍尔位移传感器的位移与输出电压的线性关系,对位移量的测量能精确到千分之一毫米,从而实现对微小位移的测量。利用该方法通过对铁的线胀系数测量结果表明：此法操作过程简单,测量精度较高。     

单水听器被动测距的脉冲周期最接近法

为了解决单水听器对运动目标的被动测距的问题,提出了一种基于最小二乘的脉冲周期最接近法。该方法适用于目标发射固定周期脉冲信号,推导了目标运动参数与单水听器接受信号脉冲周期的关系式,构建一个长方矩阵,在最小二乘意义下,计算目标最接近距离和速度。使用泰勒展开公式,分析了算法的误差特性。为单水听器被动测距提供了新方法。仿真结果表明了新方法的正确性。     

The measurement of sound radiation from room surfaces in lightweight buildings

When investigating the transmission of sound within a building it is useful to measure the sound powers being radiated by individual room surfaces. This is normally accomplished using the ‘accelerometer method’. This method is shown to be unsuitable for use in lightweight buildings, and a new ‘direct’ method, suitable for general application, is described. The equipment required by the direct method is detailed, and the magnitudes of the inaccuracies involved in its use are estimated. An account is given of the successful testing of the method on lightweight panels radiating into an anechoic chamber, and the application of the method to actual constructions is described.     

源端网络检测与抑制DDoS方法设计与实现

提出了一种源端网络DDoS攻击检测的方法。本方法基于BPF包过滤在源端网络的网关上监控数据包,通过计算网络报文的目的IP地址的信息熵进行可疑流量的检测,最终进一步使用连接跟踪的技术对可疑流量进行判别。本方法可以有效的鉴别出SYN Flood的流量,并在源端网络中直接拦截,节省计算资源。     

正则化参数求解方法研究

针对BP神经网络算法训练过程中出现的过拟合问题,提出了利用一阶原点矩,二阶原点矩,方差和极大似然估计概念的推广来计算L2正则化中正则化参数 值的方法。该方法通过对算法数据集[X,Y]中的X矩阵进行运算得到的四个 值,BP神经网络算法训练时通常采用的是贝叶斯正则化方法,贝叶斯正则化方法存在着对先验分布和数据分布依赖等问题,而利用上述概念的推广计算的参数代入L2正则化的方法简便没有应用条件限制。在BP神经网络手写数字识别的实验中,将该方法与贝叶斯正则化方法应用到实验中后的算法识别结果进行比较,正确率提高了1.14-1.50个百分点。因而计算得到的 值应用到L2正则化方法与贝叶斯正则化方法相比更能使得BP神经网络算法的泛化能力强,证明了该算法的有效性。     

一种提高CCD目标测量数据处理速度的新方法

本文提出一种提高CCD目标测量数据处理速度的新方法.该方法从操作系统紧密结合的角度出发,通过锁定物理内存和增大工作集的方法来达到提高速度的目的.本文通过目标综合测量系统的实际应用,证实该方法的可行性和有效性.     

传输线方程的高精度龙格−库塔数值求解方法

提出了一种求解传输线方程的高精度龙格-库塔(RK)方法。此方法在空间上采取高阶泰勒展开,提高了对空间微分的近似精度,减少了数值色散所带来的误差。与传统的时域有限差分法(FDTD)方法相比,在每波长采样数相同时,RK方法的计算精度更高。同时,根据Taylor模型,对外界平面波激励源进行离散,成功利用RK方法对外部场激励传输线进行求解,扩大了龙格-库塔方法在求解传输线方程时的应用范围。通过编程对平面波辐照下无限大地平面上的单导体与双导体的算例分别应用FDTD方法与RK方法进行了计算,验证了RK方法的正确性。结果表明同等计算条件下RK方法的计算精度更高。     

一种最优控制数值计算方法

本文为解决非线性微分方程自治系统的周期轨道的数值计算,提出了一种最优控制的数值计算方法。其方法的实质是利用连续的打靶法,在非线性最小二乘公式的监护下,附加惩罚函数进行控制来实现的。并利用该法计算了典型的化学反应模型。     

一种使用线阵型CCD实现高精度二维位置测量的方法

介绍了一种使用ＣＣＤ测量位置的方法。与其它ＣＣＤ位置测量系统不同，通过设计一个特殊的光学系统，实现了使用两个线阵型ＣＣＤ进行高精度二维位置坐标测量。文中对该光学系统进行了误差分析，证实该方法具有很高的测量精度。该二维位置测量方法具有一些突出的优点：系统响应速度快，可以对动态目标进行测量；测量精度高；制造成本低。上述特点使它在工业制造领域内有着广阔的应用前景。     

An energy-consistency-preserving large eddy simulation-scalar filtered mass density function (LES-SFMDF) method for high-speed flows

An energy-consistency-preserving large eddy simulation-scalar filtered mass density function (LES-SFMDF) method is developed to improve the existing LES-SFMDF method in high-speed flows, especially supersonic flows. The high-speed source term in the SFMDF transport equation is analysed theoretically from a new point of view, and then several primary principles are proposed for the LES-SFMDF to achieve a good consistency even along discontinuities. Based on these principles and further theoretical analysis, the high-speed source term of the enthalpy in the SFMDF is modelled and computed from both MC and LES variables rather than the usually used solely LES variables. This new LES-SFMDF method is used for simulating the flows in a shock tube and in a subsonic temporally developing mixing layer. This method shows a better particle energy consistency than the existing method when applied across discontinuities in supersonic laminar flows. Unlike the existing method, with this energy-consistency-preserving LES-SFMDF method, particle energy consistency is consistent with particle mass consistency so that particle energy consistency can benefit from particle velocity correction. This method also demonstrates robustness for various numbers of particles.     

Singular solitons and other solutions to a couple of nonlinear wave equations

This paper addresses the extended （G′/G）-expansion method and applies it to a couple of nonlinear wave equations. These equations are modified the Benjamin-Bona-Mahoney equation and the Boussinesq equation. This extended method reveals several solutions to these equations. Additionally, the singular soliton solutions are revealed, for these two equations, with the aid of the ansatz method.     

用近红外光谱法测定甜菜粕中总糖份和水份的方法研究

本文研究了用近红外分光光度计测定甜菜粕中总糖份和水份的分析方法，采用此方法，只需将样品粉碎、混匀、装样、扫描、数十秒就可出结果，分析结果与化学结果相符。方法快速、准确且无药品污染，精密度良好。     

Bulk velocity extraction for nano-scale Newtonian flows

The conventional velocity extraction algorithm in MDS method has difficulty to determine the small flow velocity. This study proposes a new method to calculate the bulk velocity in nano-flows. Based on the Newton?s law of viscosity, according to the calculated viscosities and shear stresses, the flow velocity can be obtained by numerical integration. This new method can overcome the difficulty existed in the conventional MDS method and improve the stability of the computational process. Numerical results show that this method is effective for the extraction of bulk velocity, no matter the bulk velocity is large or small.     

Variational iteration method for solving compressible Euler equations

This paper applies the variational iteration method to obtain approximate analytic solutions of compressible Euler equations in gas dynamics.This method is based on the use of Lagrange multiplier for identification of optimal values of parameters in a functional.Using this method,a rapid convergent sequence is produced which converges to the exact solutions of the problem.Numerical results and comparison with other two numerical solutions verify that this method is very convenient and efficient.