Prospect for Cosmological Parameter Estimation Using Future Hubble Parameter Measurements

We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain cosmological parameters using 52 current Hubble parameter data including the Hubble constant measurement from the Hubble Space Telescope. Then we simulate the baryon acoustic oscillation signals from WFIRST (Wide-Field Infrared Survey Telescope) covering the redshift range of z ∈[0.5,2] and the redshift drift data from E-ELT (European Extremely Large Telescope) in the redshift range of z ∈[2,5]. It is shown that solely using the current Hubble parameter data could give fairly good constraints on cosmological parameters. Compared to the current Hubble parameter data, with the WFIRST observation the H(z) constraints on dark energy would be improved slightly, while with the E-ELT observation the H(z) constraints on dark energy is enormously improved.     

中国评价核参数库和IAEA之推荐输入参数库

概述了为核反应模型计算用的“中国评价核参数库”的发展和结构 ,指出了该数据库在国际核反应数据模型计算的“推荐输入参数库”中的作用和地位 .目前正研制更新的CENPL ,一方面将检验、更新和扩充数据 ,特别注重研究适用于更高能区和非稳定核区的模型参数 ;另一方面发展其检索软件和网络软件 ,实现网络在线服务. The Chinese Evaluated Nuclear Parameter Library (CENPL) for the model calculations of nuclear reactions was developed in the past ten years. The International Atomic Energy Agency has constructed a Reference Input Parameter Library (RIPL) for the calculations of nuclear reaction data in the meantime. All data files of CENPL are adopted as the RIPL Starter Files. The model parameters estimated and recommended by our group are specially selected as recommended files. The updated CENPL is being developed...     

Cavitation: Parameter control

A method for increasing the temperature and pressure in a collapsing bubble due to centrifuging was proposed. Based on the proposed method, the possibility of progress in the study of not only acoustic (cavitation) nucleosynthesis (sonofusion), but also other important problems, e.g., mechanocracking of heavy hydrocarbons, is considered.     

Julia Sets in Parameter Spaces

Given a complex number λ of modulus 1, we show that the bifurcation locus of the one parameter family {f _b (z)=λz+b z ²+z ³} _{b ∈ ℂ} contains quasi-conformal copies of the quadratic Julia set J(λz+z ²). As a corollary, we show that when the Julia set J(λz+z ²) is not locally connected (for example when z↦λz+z ² has a Cremer point at 0), the bifurcation locus is not locally connected. To our knowledge, this is the first example of complex analytic parameter space of dimension 1, with connected but non-locally connected bifurcation locus. We also show that the set of complex numbers λ of modulus 1, for which at least one of the parameter rays has a non-trivial accumulation set, contains a dense G _δ subset of S ¹. Received: 22 September 2000 / Accepted: 16 January 2001     

Parameter estimation for hysteretic systems

The differential system characterization of hysteretic system is well known. The problem of estimating the parameters of this system on the basis of input-output data, possibly noise corrupted, is considered. It turns out that the estimation problem is a non-linear optimization problem. The Gauss Newton method is used in setting up a two-stage iterative least squares algorithm. The usefulness of the algorithm is validated through its application to various simulated time histories from the hysteretic model.     

Parameter counting for neutrino mixing

The content of physical masses, mixing angles and CP violating phases in the lepton sector of the extended standard model, both renormalizable and non-renormalizable, with arbitrary numbers of singlet and left-handed doublet neutrinos is systematically analyzed in the weak basis. Received: 25 April 2000 / Revised version: 16 June 2000 / Published online: 8 September 2000     

Parameter interpolation in speech synthesis

A comparison has been made of the transition properties of six types of speech synthesizer parameters: serial resonance, prediction coefficients, reflection coefficients, area functions, parallel resonance, and, finally, a simple set of articulatory parameters. The first four synthesizers are formally equivalent and can be made to produce identical steady-state sounds (targets). The last two involve approximations, but achieve similar targets. Formant paths between targets will differ according to the parameter type used during interpolation. Each type was tested on nonsense words spanning a wide range of parameter values. Linear interpolation of synthesizer parameters was used to determine a path between target values. The resultant data were then converted to formant values and plotted as a spectrographic (frequency versus time) representation. Small differences in formant frequency (versus linear transitions of formant frequency and bandwidth) were common, and some quite large differences in formant bandwidths were observed in certain cases.     

高能闪光照相对电子束参数的要求

对高能闪光机光源性能用Monte-Carlo方法模拟研究发现：并非击靶电子束半径越小、发射度越低, 闪光机的照相性能就会越好. 研究结果表明：为了使闪光照相图像视面上照射量分布比较均匀, 对束半径与电子束归一发射度有一个联合限制, 对于20MeV闪光机, 如果击靶电子束有效半径是0.12cm, 那么仅当束归一发射度≥550cm.mrad时,在2°内的照射量不均匀性才小于5%.     

Parameter Estimation for Multiscale Diffusions

We study the problem of parameter estimation for time-series possessing two, widely separated, characteristic time scales. The aim is to understand situations where it is desirable to fit a homogenized single-scale model to such multiscale data. We demonstrate, numerically and analytically, that if the data is sampled too finely then the parameter fit will fail, in that the correct parameters in the homogenized model are not identified. We also show, numerically and analytically, that if the data is subsampled at an appropriate rate then it is possible to estimate the coefficients of the homogenized model correctly. The ideas are studied in the context of thermally activated motion in a two-scale potential. However the ideas may be expected to transfer to other situations where it is desirable to fit an averaged or homogenized equation to multiscale data.     

Parameter estimation using balanced synchronization

Synchronization between experimental observations and a dynamical model with undetermined parameters can assist in completing the specification of the model parameters. The quality of the synchronization, a cost function to be minimized, typically depends on the difference between the data time series and the model time series. If the coupling between the data and the model is too strong, this cost function is small for any data and any model, and the variation of the cost function with respect to the parameters of interest is too small to permit selection of a value of the parameters. If the coupling is too small, synchronization is lost. We introduce two methods for balancing the competing desires of a small cost function and the numerical ability to determine parameters accurately. One method of ‘balanced’ synchronization adds a requirement that the conditional Lyapunov exponent of the model system, conditioned on being driven by the data, remain negative but small. The other method allows the coupling to vary in time according to the error in synchronization. This second method succeeds because the data and the model exhibit generalized synchronization in the region where the parameters of the model are well determined.     

Parameter estimation with mixed quantum states

We consider quantum enhanced measurements with initially mixed states. We show very generally that for any linear propagation of the initial state that depends smoothly on the parameter to be estimated, the sensitivity is bound by the maximal sensitivity that can be achieved for any of the pure states from which the initial density matrix is mixed. This provides a very general proof that purely classical correlations cannot improve the sensitivity of parameter estimation schemes in quantum enhanced measurement schemes.     

Parameter space of general gauge mediation

We study a subspace of General Gauge Mediation (GGM) models which generalize models of gauge mediation. We find superpartner spectra that are markedly different from those of typical gauge and gaugino mediation scenarios. While typical gauge mediation predictions of either a neutralino or stau next-to-lightest supersymmetric particle (NLSP) are easily reproducible with the GGM parameters, chargino and sneutrino NLSPs are generic for many reasonable choices of GGM parameters.     

广义Julia 集的参数辨识

本文研究了一类相当广泛的复系统Julia 集的参数辨识问题.基于非线性反馈控制器和差分方程稳定性理论, 设计了普遍适用的自适应同步控制器和参数自适应律的解析表达式.理论证明设计的控制器可使得此类广义复系统Julia 集达到同步,并且可以辨识广义Julia 集的未知参数.通过仿真实例验证了该方法的有效性.另外, 本文特别地讨论了最基本的Julia 集的参数辨识问题. 关键词： Julia集 参数辨识 同步     

Parameter Study on Far-Field Sub-Diffraction-Limited Hyperlens

Influence of hyperlens structure parameters, such as curvature radius and layer number, and incident wavelength on the beam propagation is numerically investigated by FDTD. It is found that the intensity and the full width at half maximum (FWHM) of the output beam can be controlled by the structure parameters and operating wavelength. The optimized structureparameters and operating wavelength are obtained, which will be of great significance in design and fabrication of optical hyperlens with high resolution.     

模型及其参数对确定K介子有效质量的影响

分别使用线性和非线性Walecka模型,讨论了重子标量密度ρS和矢量密度ρB的关系.运用相对论平均场理论给出了不同模型下ρ_S-ρ_B关系曲线.利用这些结果,分析了模型和参数组对核物质中K介子有效质量影响的大小,得到了不同参数组下K介子有效质量随核物质密度的变化关系曲线.同时计算了非对称核物质中K介子有效质量在不同模型和不同参数下的有效质量的曲线,并与对称核物质中的情况进行了比较.     

星载激光相干测高计的参量设计

为使星载激光高度计实现高空间分辨力、高距离精度,提出了联合采用调频光纤激光器和相干测距的方法.详细讨论了这种方法的实现方案,并对方案中的激光发射功率、望远镜口径以及脉冲宽度对距离精度及信噪比的影响进行数值模拟.对系统参量进行分析,得到了相关参量的关系和优化的参量.结果表明,当望远镜口径为400 mm时,啁啾调频速率为1 MHz/μs,脉冲时间宽度150～350 μs, 发射功率10 W左右时,基于相干测距的星载激光高度计可以实现距离精度小于15 cm的技术指标.