Numerical analysis for factorial data analysis. Part II: Special purpose hardware—the programmable systolic array SARDA

The second part of this paper deals with the systolic implementation of the computational kernel for factorial data analysis, defined in Part I, on special-purpose hardware. The framework of the study is that a sequence of different algorithms has to be performed on a unique hardware array. This fact has led us to the design of the programmable systolic array SARDA: this is a triangular array which consists of programmable nodes with local memory and programmable orthogonal connections.     

飞行器气动参数辨识进展

飞行器气动参数辨识研究的主题,是应用系统辨识技术从飞行试验数据求取气动力,从而建立飞行器动力学系统的数学模型.它研究的对象是飞行器;解决的是空气动力学问题;采用的基本方程是飞行动力学的运动方程组;应用的研究手段是现代控制论的滤波、预测和估计理论.它是处于空气动力学、飞行力学、弹性力学和现代控制论之间的应用性研究课题. 本文综述了国内外公开发表的飞行器参数辨识研究的理论结果和实践经验,分八个专题——模型辨识,参数估计,数据预处理和相容性检验,试验设计与最佳输入,弹性与非定常效应,频域辨识,闭环辨识,辨识准度与系统验证——评述其研究进展和现状.      

激波风洞信号测量仪

本文叙述了一种用于激波风洞实验研究中的以微机为基础的多功能智能测量仪表,叙述了其构成部分和性能、硬件结构和原理、软件编制以及将BASIC程序写入EPROM的过程。     

一种基于复数域微分的资料同化新方法

提出了一种基于复数域微分的资料同化新方法. 针对变分资料同化中目标泛函梯度计算复杂和精度不高的问题, 首先利用复变量求导法把梯度分析过程转化为复变泛函的数值计算, 进而高效和高精度地获得梯度值; 然后结合经典的最优化方法, 给出了非线性物理系统资料同化问题的新求解算法; 最后对典型混沌系统和包含“开关”现象的单格点比湿发展方程进行了资料同化数值实验, 结果表明新方法能非常有效地估计出非线性动力预报模式的初始条件. 关键词： 资料同化 复数域微分 非线性物理系统 梯度分析     

合成孔径雷达光学处理器的检测方法

本文以一个通用合成孔径雷达光学处理器(简称OSARP)的检测为例,来说明OSARP的检测方法。给出OSARP的每个可调部件与合成孔径雷达(简称SAR)数据片的各特征参数间的关系,通过测量调整量求得OSARP的适用范围;用普通检测目标加位移透镜,来检测OSARP的成像质量。同时用模拟的SAR数据片,以另一种方法对OSARP做检测,结果相同。最后处理了真实SAR数据片,用来展示SAR和OSARP的综合成像质量。文中给出一些实验照片和数据,结果表明,本检测方法是可行的。     

体全息存储系统读出图像的放大率的补偿算法研究

在1∶1体全息存储系统的读出过程中,保证图像的不失真和降低误码率是最关键的问题。提出了一种新颖的放大率补偿算法,定量分析了放大率偏移误差对图像的影响,并通过理论推导和实验模拟证明了这一算法的可行性。     

Lazy structure-activity relationships (lazar) for the prediction of rodent carcinogenicity and Salmonella mutagenicity

lazar is a new tool for the prediction of toxic properties of chemical structures. It derives predictions for query structures from a database with experimentally determined toxicity data. lazar generates predictions by searching the database for compounds that are similar with respect to a given toxic activity and calculating the prediction from their activities. Apart form the prediction, lazar provides the rationales (structural features and similar compounds) for the prediction and a reliable condence index that indicates, if a query structure falls within the applicability domain of the training database. Leave-one-out (LOO) crossvalidation experiments were carried out for 10 carcinogenicity endpoints ({female|male} {hamster|mouse|rat} carcinogenicity and aggregate endpoints {hamster|mouse|rat} carcinogenicity and rodent carcinogenicity) and Salmonella mutagenicity from the Carcinogenic Potency Database (CPDB). An external validation of Salmonella mutagenicity predictions was performed with a dataset of 3895 structures. Leave-one-out and external validation experiments indicate that Salmonella mutagenicity can be predicted with 85% accuracy for compounds within the applicability domain of the CPDB. The LOO accuracy of lazar predictions of rodent carcinogenicity is 86%, the accuracies for other carcinogenicity endpoints vary between 78 and 95% for structures within the applicability domain.     

Time and direction of arrival detection and filtering for imaging in strongly scattering random media

We study detection and imaging of small reflectors in heavy clutter, using an array of transducers that emits and receives sound waves. Heavy clutter means that multiple scattering of the waves in the heterogeneous host medium is strong and overwhelms the arrivals from the small reflectors. Building on the adaptive time-frequency filter of [Borcea et al, SIIMS 2011;4(3)], we propose a robust method for detecting the direction of arrival of the direct echoes from the small reflectors, and suppressing the unwanted clutter backscatter. This improves the resolution of imaging. We illustrate the performance of the method with realistic numerical simulations in a non-destructive testing setup.     

基于扫描相机的激光三维成像研究

随着条纹管器件技术的发展,条纹管作为瞬态光学器件的应用不再局限于高速摄影和光谱学研究领域。建立以单狭缝条纹管为核心器件的扫描相机激光成像系统,对目标进行推扫成像,获得原始条纹图像,并进行特征数据提取和三维重建。理论计算出的两目标的距离差与实际距离差较接近,从而验证采用该系统作激光雷达成像的可行性。实验结果表明,基于扫描相机激光雷达具有高分辨率,具有较好的应用前景。     

系统可靠度置信下限估计方法及其应用

针对寿命服从指数分布的随机截尾样本,研究单元及系统可靠度的评估方法,给出了系统可靠度置信下限估计方法,该方法同样适用于工程中常见的定时截尾样本与定数截尾样本的系统可靠度评估问题。首先通过分位数填充算法将随机截尾数据补充成虚拟完全样本,然后基于信仰推断,给出系统内每个单元失效率的信仰分布,最后根据指数分布的特点,从失效率角度出发,采用蒙特卡罗法对单元失效率进行随机抽样,结合系统可靠性模型得到系统失效率的分布,在给定置信水平下即可得到系统失效率上限,进而得到工程上特别关注的系统可靠度置信下限。