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1.
最小二乘法是求解精确晶格参数的基本方法.讨论了使用和不使用校正函数情形下的科恩最小二乘法,给出了所有晶系的法方程、晶格参数、误差估计的计算公式,以及计算晶格参数、校正函数参数的阻尼最小二乘迭代算法,该方法具有普适性,有大的收敛范围和快的收敛速度.作为应用例子,计算了数个不同晶系晶体的晶格参数,说明最小二乘法是获得高精度晶格参数的计算方法;用阻尼最小二乘法计算了ChuG校正函数的参数,表明该方法是获得校正函数参数的有效方法.  相似文献   

2.
兰斌  吴小霞  杨洪波  蒋权  张正铎 《红外与激光工程》2017,46(6):617001-0617001(7)
为了解除4 m轻量化反射镜支撑系统间存在的相互耦合作用,提出了采用广义最小二乘法进行主动光学的模式定标计算。首先,介绍了4 m轻量化反射镜的支撑系统,推导出液压Whiffletree支撑系统工作下主动光学校正力组满足解耦条件的等式约束方程,将节点面积加权因子修正后的Zernike多项式面形拟合过程作为有限元分析前处理,建立主动光学的响应矩阵。其次,采用广义最小二乘法求解同时满足等式和不等式约束下的最佳校正力组。最后,将提出的方法应用于重力印透效应产生的镜面变形主动力解算,分析不同阻尼因子对解算结果的影响。结果表明:阻尼因子取7.4e-9时,达到了满足约束条件的最佳校正效果,镜面面形均方根由最初的271.5 nm通过校正后变为8.3 nm。验证了广义最小二乘法应用于4 m轻量化反射镜主动光学校正力组解算的可行性。  相似文献   

3.
基于遗传算法的雷达组网误差配准算法   总被引:1,自引:0,他引:1  
系统误差校正是雷达组网的关键问题,传统的误差校正方法采用最小均方估计法或极大似然法,这些方法受随机误差影响,计算量大,难以在工程中应用。本文在实时精度控制法(RTOC)的基础上,通过构造误差配准的目标函数,将误差配准转换为非线性优化问题,并采用遗传算法进行寻优。该方法采用非参数化的方法进行误差配准,克服了RTOC和最小二乘算法中线性化带来的误差,提高了误差估计的精度。仿真和实际数据测试表明,本文提供的方法能有效地进行组网雷达误差配准。  相似文献   

4.
目前拉格朗日乘因子法是求解分布式目标最优极化的主要算法.该算法需要计算一个以拉格朗日乘法因子为自变量的六次多项式方程.针对拉格朗日乘因子法在计算该多项式方程根时存在的问题,提出了一种优化求解法.在理论证明该方程最大根对应天线最大接收功率而最小根对应天线最小接收功率的基础上,该优化求解法通过缩小迭代搜索区间获取方程最大、最小根,然后利用这些根与天线极化之间的关系式求解目标最优极化.为了提高迭代收敛速度,通过理论分析确定了最小初始迭代搜索区间.实验结果表明, 该优化求解法消除了算法对于拉格朗日乘因子初始值的依赖,提高了算法的运算速度.  相似文献   

5.
针对信源方位信息存在偏差时阵元位置误差进行讨论,提出了一种基于单信源的误差校正方法。该方法中假设接收阵列可精密旋转,达到多个信源分时校正的效果,从而获得大量样本,先用最小二乘拟合法对校正源的方位信息进行估计,再采用剔野的方式剔除某些阵元位置误差较大的数据,达到校正信源方位信息的目的,然后再次采用最小二乘法校正阵元位置误差,最后仿真验证了该方法的有效性,并对比分析了阵元位置误差校正前后的MUSIC谱测角。  相似文献   

6.
赵艺兵  温秀兰   《电子器件》2007,30(4):1391-1393
提出了将进化策略算法用于对测试系统中信号转换电路的非线性误差进行校正.该算法基于实数编码,采用(μ λ)选择策略和高斯变异算子,即父代种群参与竞争;同时建立了用进化策略校正非线性误差时目标函数的数学模型.实验结果表明,用进化策略对信号转换电路进行非线性校正不仅能够自动搜索到最优多项式,而且精度高于最小二乘法和改进遗传算法.该方法同样适用于对测试系统中传感器等其它电子测量元件中存在的非线性误差进行校正.  相似文献   

7.
曲长文  王昌海  徐征 《信号处理》2012,28(4):533-538
多机无源融合定位中的误差配准是目前多传感器误差配中的难点之一.当无源传感器获得的观测量存在系统误差却不进行配准时,多机融合定位的效果将受到严重影响.针对这一情况,在多机只测角无源定位问题中提出了一种基于非线性最小二乘(NLS)的误差配准算法.该算法将多机只测角误差配准问题转换为非线性最小二乘估计问题,并采用高斯-牛顿法求解,即先将非线性量测方程线性化并采用加权最小二乘进行估计,然后进行迭代直至收敛到最优估计值.仿真结果表明,与EKF配准算法相比,当观测时间足够长时,本文提出的NLS误差配准算法的定位误差可以接近克拉美罗限(CRLB),并且对系统误差的估计精度非常高.  相似文献   

8.
雷达测距拟合微分求速方法研究   总被引:2,自引:1,他引:1  
雷达测距元的高采样率为测距拟合微分求速提供了基础条件,但必须对测距元数据进行合理的平滑和拟合以消除相关噪声的影响.文中采用自由节点多项式样条函数建立雷达测距元拟合函数,通过最小二乘优化设计的方法搜寻最优节点,使节点分布自适应目标运动规律,再微分求速.通过仿真和实例计算,对该方法处理过程和求解速度精度水平进行了分析.  相似文献   

9.
网络流量是具有复杂非线性、不确定时变性的混沌时间序列.为提高标准最小二乘支持向量机的预测精度与自适应性,提出一种基于动态加权最小二乘支持向量机的网络流量混沌预测方法.该方法在标准LS-SVM回归机的训练样本误差设置时间权,增强对非线性样本的逼近能力.然后结合滚动窗与迭代求逆法实现模型动态在线校正,进而克服网络变化时的累积误差.仿真实验结果表明,相对常规LS-SVM,该模型能降低预测误差、减少计算时间,实现高精度实时混沌流量估计.  相似文献   

10.
《无线电工程》2016,(2):65-68
针对非合作目标多雷达组网中的系统误差配准问题,介绍了基于地心地固坐标系的三维空间配准模型,以及常用的雷达误差配准方法——最小二乘法。为了能够实时估计出系统偏差,并解决最小二乘等批处理算法在求解系统误差过程中数据量、计算量和存储量随时间递增的问题,提出了基于广义最小二乘法的有限记忆最小二乘法。通过一个实例,对新算法进行Matlab仿真,结果证明了算法的正确性和有效性。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

13.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

14.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

15.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

16.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

17.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

18.
In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line(w), the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line(x), the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines(y), the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line(z) in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line(q) in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution(λ/△ 2) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.  相似文献   

19.
High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.  相似文献   

20.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

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