非正侧视阵机载雷达杂波抑制算法研究

非正侧视阵机载雷达的空时二维杂波谱随距离的变化而变化,即在距离维是非均匀的,因此不能直接由邻近距离单元估计杂波协方差矩阵。为了解决这种由距离依赖性引起的杂波特别是近程杂波的非均匀问题,该文对多普勒频移算法进行了改进,将经过多普勒频移补偿后的数据转换到阵元-多普勒域,在多普勒域进行空间频率补偿,提高其在主杂波区的性能。改进算法既充分利用了原算法简单,易于实现的特点,又克服了原算法在大偏航角下性能下降的缺陷,仿真结果验证了该算法的有效性。     

基于数据仓库的企业DSS开发

本文结合实际开发经验,提出信息系统开发的一种新思路,即在ＭＩＳ系统基础之上建立数据仓库,又以数据仓库为基础建立决策支持系统。     

基于分布式数据仓库的电信信息共享平台的研究

随着信息化水平的逐渐提高,信息的共享越来越受到人们的关注,电信行业也不例外;针对电信行业信息中出现的管理和共享问题,介绍采用数据仓库技术实现信息共享的方法,并在此基础上提出了信息共享平台模型;模型建立在分布式数据仓库基础上,通过维度建模法创建了数据仓库模型,并提出多维分析流程,可以利用分布式数据仓库和网络技术实现信息的共享;数据仓库技术的应用和信息共享平台模型的建立,能最大限度地发挥电信信息的价值,对提高信息的共享度起到重要作用。     

DW中一种基于本体的语义集成方法研究

文中介绍了数据仓库领域一种基于本体的语义集成方法。首先建立领域本体和数据源的局部本体,然后通过局部本体对应的概念树间的映射算法得到数据源全局本体,再和领域本体映射,得到映射关系。最后通过本体推理,得出隐含的语义关系,用最终的语义关系来指导数据抽取、转换和加载过程,实现数据仓库语义程度上的数据集成。     

DW45万能式断路器的选型和使用

介绍了DW45智能型万能式断路器设计选型和使用维护方面的几个重点问题.     

THERMUS—A thermal model package for ROOT

THERMUS is a package of C++ classes and functions allowing statistical-thermal model analyses of particle production in relativistic heavy-ion collisions to be performed within the ROOT framework of analysis. Calculations are possible within three statistical ensembles; a grand-canonical treatment of the conserved charges B, S and Q, a fully canonical treatment of the conserved charges, and a mixed-canonical ensemble combining a canonical treatment of strangeness with a grand-canonical treatment of baryon number and electric charge. THERMUS allows for the assignment of decay chains and detector efficiencies specific to each particle yield, which enables sensible fitting of model parameters to experimental data.

Program summary

Program title: THERMUS, version 2.1Catalogue identifier: AEBW_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBW_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 17 152No. of bytes in distributed program, including test data, etc.: 93 581Distribution format: tar.gzProgramming language: C++Computer: PC, Pentium 4, 1 GB RAM (not hardware dependent)Operating system: Linux: FEDORA, RedHat, etc.Classification: 17.7External routines: Numerical Recipes in C [1], ROOT [2]Nature of problem: Statistical-thermal model analyses of heavy-ion collision data require the calculation of both primordial particle densities and contributions from resonance decay. A set of thermal parameters (the number depending on the particular model imposed) and a set of thermalized particles, with their decays specified, is required as input to these models. The output is then a complete set of primordial thermal quantities for each particle, together with the contributions to the final particle yields from resonance decay. In many applications of statistical-thermal models it is required to fit experimental particle multiplicities or particle ratios. In such analyses, the input is a set of experimental yields and ratios, a set of particles comprising the assumed hadron resonance gas formed in the collision and the constraints to be placed on the system. The thermal model parameters consistent with the specified constraints leading to the best-fit to the experimental data are then output.Solution method: THERMUS is a package designed for incorporation into the ROOT [2] framework, used extensively by the heavy-ion community. As such, it utilizes a great deal of ROOT's functionality in its operation. ROOT features used in THERMUS include its containers, the wrapper TMinuit implementing the MINUIT fitting package, and the TMath class of mathematical functions and routines. Arguably the most useful feature is the utilization of CINT as the control language, which allows interactive access to the THERMUS objects. Three distinct statistical ensembles are included in THERMUS, while additional options to include quantum statistics, resonance width and excluded volume corrections are also available. THERMUS provides a default particle list including all mesons (up to the (2045)) and baryons (up to the Ω⁻) listed in the July 2002 Particle Physics Booklet [3]. For each typically unstable particle in this list, THERMUS includes a text-file listing its decays. With thermal parameters specified, THERMUS calculates primordial thermal densities either by performing numerical integrations or else, in the case of the Boltzmann approximation without resonance width in the grand-canonical ensemble, by evaluating Bessel functions. Particle decay chains are then used to evaluate experimental observables (i.e. particle yields following resonance decay). Additional detector efficiency factors allow fine-tuning of the model predictions to a specific detector arrangement. When parameters are required to be constrained, use is made of the ‘Numerical Recipes in C’ [1] function which applies the Broyden globally convergent secant method of solving nonlinear systems of equations. Since the NRC software is not freely-available, it has to be purchased by the user. THERMUS provides the means of imposing a large number of constraints on the chosen model (amongst others, THERMUS can fix the baryon-to-charge ratio of the system, the strangeness density of the system and the primordial energy per hadron). Fits to experimental data are accomplished in THERMUS by using the ROOT TMinuit class. In its default operation, the standard χ² function is minimized, yielding the set of best-fit thermal parameters. THERMUS allows the assignment of separate decay chains to each experimental input. In this way, the model is able to match the specific feed-down corrections of a particular data set.Running time: Depending on the analysis required, run-times vary from seconds (for the evaluation of particle multiplicities given a set of parameters) to several minutes (for fits to experimental data subject to constraints).References:

[1]

W.H. Press, S.A. Teukolsky, W.T. Vetterling, B.P. Flannery, Numerical Recipes in C: The Art of Scientific Computing, Cambridge University Press, Cambridge, 2002.

[2]

R. Brun, F. Rademakers, Nucl. Inst. Meth. Phys. Res. A 389 (1997) 81. See also http://root.cern.ch/.

[3]

K. Hagiwara et al., Phys. Rev. D 66 (2002) 010001.

     

数据仓库技术在教学管理信息系统中的应用研究

在现有信息系统基础上建立数据仓库应用是信息系统开发面临的新课题。文章介绍了数据仓库的基本概念和系统结构,针对教学管理信息系统中的数据特性,探讨了数据仓库中的数据组织的基本方法。     

Periodic peristalsis enhancing the high solids enzymatic hydrolysis performance of steam exploded corn stover biomass

Enzymatic hydrolysis beyond 15% solid loading offers many advantages such as increased sugar and ethanol concentrations and decreased capital cost. However, difficult mixing and handling limited its industrialized application. A novel intensification method, periodic peristalsis, had been exploited to improve the high solids enzymatic hydrolysis performance of steam exploded corn stover (SECS). The optimal steam explosion conditions were 200 °C and 8 min, under which glucan and xylan recovery was 94.3% and 64.8%, respectively. Glucan and xylan conversions in periodic peristalsis enzymatic hydrolysis (PPEH) were 28.0–38.5% and 25.0–36.0% higher than those in static state enzymatic hydrolysis with solid loading increasing from 1% to 30%, respectively, while they were 1.0–11.2% and 3.0–9.2% higher than those in incubator shaker enzymatic hydrolysis (ISEH). Glucan and xylan conversion in PPEH at 21% solid loading reached 71.2% and 70.3%, respectively. Periodic peristalsis also facilitated fed-batch enzymatic hydrolysis of which SECS was added completely before transition point. Results presented that PPEH shortened the transition point time from solid state to slurry state, decreased the viscosity of hydrolysis mixture, and reduced the denaturation effect of enzymes compared with ISEH, and hence improve the high solids enzymatic hydrolysis efficiency.     

露天矿卡车调度系统数据处理技术的研究

利用数据仓库DW(Data Warehouse)、联机分析处理OLAP(On—Line Analytical Processing)、数据挖掘DM(Data Mining)等技术对露天矿卡车调度系统存有的大量数据,提出分析处理的思路和方法。     

Optimisation of total phenolic acids extraction from mandarin peels using microwave energy: The importance of the Maillard reaction

Microwave processing has been used for the extraction of antioxidants from mandarin peels using deionised water as the solvent. Optimum extraction conditions under constant heat load per unit mass were as follows: microwave power, 400 W; extraction time, 3 min; solid to solvent ratio, 1:2; and extraction temperature below 135 °C. These conditions did not change the colour of the extract significantly under neutral (pH 4.5-4.9) and acidic conditions (pH 1.5-2.5). The amounts of antioxidants, which were extracted when the heat load per unit mass was held constant, were not significantly affected by the solid to solvent ratio used, so the maximum solid to solvent ratio of 1:2 used here is recommended to minimise the amount of solvent used. The colour of the extract was more greatly affected by the extraction temperature than by the solid to solvent ratio. The total phenolic contents of mandarin peels were evaluated using the Folin-Ciocalteu assay (FCR) and the trends were compared with the results of the Oxygen Absorbance Radical Capacity (ORAC) assays. The presence of Maillard rections and Maillard by-products were also investigated at higher extraction temperatures and analysed by the High Performance Liquid Chromatography (HPLC) method. The results demonstrated that microwave extraction (MWE) is a fast and reliable method for phenolic compound extraction from citrus marc with the minimum use of solvent.