Using interval arithmetic for robust state feedback design

A problem of a modal P-regulator synthesis for a linear multivariable dynamical system with uncertain (interval) parameters in state space is considered. The designed regulator has to place all coefficients of the system characteristic polynomial within assigned intervals. We have developed the approach proposed earlier in Dugarova and Smagina (Avtomat. i Telemech. 11 (1990) 176) and proved a direct correlation between interval system controllability and existence of robust modal P-regulator.     

On the complete instability of interval polynomials

In this paper, we study “complete instability” of interval polynomials, which is the counterpart of classical robust stability. That is, the objective is to check if all polynomials in the family are unstable. If not, a subsequent goal is to find a stable polynomial. To this end, we first propose a randomized algorithm which is based on a (recursive) necessary condition for Hurwitz stability. The second contribution of this paper is to provide a probability-one estimate of the volume of stable polynomials. These results are based on a combination of deterministic and randomized methods. Finally, we present two numerical examples and simulations showing the efficiency of the proposed methodology for small and medium-size problems.     

The computational complexity of approximating the minimal perturbation scaling to achieve instability in an interval matrix

An interval matrix can be represented in terms of a center matrix and a nonnegative error matrix, specifying maximum elementwise perturbations from the center matrix. A commonly proposed robust stability (regularity) characterization for an interval matrix with a stable (nonsingular) center matrix identifies the minimum scaling of this error matrix for which instability (singularity) is achieved. In this paper it is shown that approximating this minimum scaling is a MAX-SNP-hard problem. This implies that in the general case, unless the class of deterministic polynomial-time decision problems, P, equals the class of nondeterministic polynomial-time decision problems, NP, thought to be highly unlikely, this minimum scaling cannot be approximated with a ratio arbitrarily close to unity in polynomial time.This research was supported by the National Science Foundation under Grant ECS-8857019.     

基于纹理特征的指纹识别算法

基于纹理特征的指纹识别方法,具有计算量小的特点。本文对该指纹识别算法进行了系统研究,提出了一套新颖的方向图修正算法,对于噪声相对较小的情况具有良好的效果。本文对多窗口法求块方向图给出了减少运算量的方法;在方向滤波器设计方面,给出了一个方向滤波器的闭合等式,可以简化方向滤波器设计,大大减少运算量,并取得了较好的增强效果;在中心点求取方面,提出了一种新的粗搜索算法,可以减少计算量,加快中心区域搜索速度。     

A new version of the CADNA library for estimating round-off error propagation in Fortran programs

The CADNA library enables one to estimate, using a probabilistic approach, round-off error propagation in any simulation program. CADNA provides new numerical types, the so-called stochastic types, on which round-off errors can be estimated. Furthermore CADNA contains the definition of arithmetic and relational operators which are overloaded for stochastic variables and the definition of mathematical functions which can be used with stochastic arguments. On 64-bit processors, depending on the rounding mode chosen, the mathematical library associated with the GNU Fortran compiler may provide incorrect results or generate severe bugs. Therefore the CADNA library has been improved to enable the numerical validation of programs on 64-bit processors.

New version program summary

Program title: CADNACatalogue identifier: AEAT_v1_1Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAT_v1_1.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.: 28 488No. of bytes in distributed program, including test data, etc.: 463 778Distribution format: tar.gzProgramming language: FortranNOTE: A C++ version of this program is available in the Library as AEGQ_v1_0Computer: PC running LINUX with an i686 or an ia64 processor, UNIX workstations including SUN, IBMOperating system: LINUX, UNIXClassification: 6.5Catalogue identifier of previous version: AEAT_v1_0Journal reference of previous version: Comput. Phys. Commun. 178 (2008) 933Does the new version supersede the previous version?: YesNature of problem: A simulation program which uses floating-point arithmetic generates round-off errors, due to the rounding performed at each assignment and at each arithmetic operation. Round-off error propagation may invalidate the result of a program. The CADNA library enables one to estimate round-off error propagation in any simulation program and to detect all numerical instabilities that may occur at run time.Solution method: The CADNA library [1-3] implements Discrete Stochastic Arithmetic [4,5] which is based on a probabilistic model of round-off errors. The program is run several times with a random rounding mode generating different results each time. From this set of results, CADNA estimates the number of exact significant digits in the result that would have been computed with standard floating-point arithmetic.Reasons for new version: On 64-bit processors, the mathematical library associated with the GNU Fortran compiler may provide incorrect results or generate severe bugs with rounding towards −∞ and +∞, which the random rounding mode is based on. Therefore a particular definition of mathematical functions for stochastic arguments has been included in the CADNA library to enable its use with the GNU Fortran compiler on 64-bit processors.Summary of revisions: If CADNA is used on a 64-bit processor with the GNU Fortran compiler, mathematical functions are computed with rounding to the nearest, otherwise they are computed with the random rounding mode. It must be pointed out that the knowledge of the accuracy of the stochastic argument of a mathematical function is never lost.Restrictions: CADNA requires a Fortran 90 (or newer) compiler. In the program to be linked with the CADNA library, round-off errors on complex variables cannot be estimated. Furthermore array functions such as product or sum must not be used. Only the arithmetic operators and the abs, min, max and sqrt functions can be used for arrays.Additional comments: In the library archive, users are advised to read the INSTALL file first. The doc directory contains a user guide named ug.cadna.pdf which shows how to control the numerical accuracy of a program using CADNA, provides installation instructions and describes test runs. The source code, which is located in the src directory, consists of one assembly language file (cadna_rounding.s) and eighteen Fortran language files. cadna_rounding.s is a symbolic link to the assembly file corresponding to the processor and the Fortran compiler used. This assembly file contains routines which are frequently called in the CADNA Fortran files to change the rounding mode. The Fortran language files contain the definition of the stochastic types on which the control of accuracy can be performed, CADNA specific functions (for instance to enable or disable the detection of numerical instabilities), the definition of arithmetic and relational operators which are overloaded for stochastic variables and the definition of mathematical functions which can be used with stochastic arguments. The examples directory contains seven test runs which illustrate the use of the CADNA library and the benefits of Discrete Stochastic Arithmetic.Running time: The version of a code which uses CADNA runs at least three times slower than its floating-point version. This cost depends on the computer architecture and can be higher if the detection of numerical instabilities is enabled. In this case, the cost may be related to the number of instabilities detected.References:

[1]

The CADNA library, URL address: http://www.lip6.fr/cadna.

[2]

F. Jézéquel, J.-M. Chesneaux, CADNA: a library for estimating round-off error propagation, Comput. Phys. Commun. 178 (12) (2008) 933-955.

[3]

N.S. Scott, F. Jézéquel, C. Denis, J.-M. Chesneaux, Numerical ‘health check’ for scientific codes: the CADNA approach, Comput. Phys. Commun. 176 (8) (2007) 507-521.

[4]

J. Vignes, A stochastic arithmetic for reliable scientific computation, Math. Comput. Simul. 35 (1993) 233-261.

[5]

J. Vignes, Discrete stochastic arithmetic for validating results of numerical software, Numer. Algorithms 37 (2004) 377-390.

     

The design and implementation of the nag master library file system

The NAG Master Library File System is described in terms of its structure and function, with particular reference to the rationale and design constraints adopted and to the actual functioning of the system within the NAG project.     

Optimal design and verification of temporal and spatial filters using second-order cone programming approach

11 Introduction The filters are widely used in many applications of signal processing. Filter design is an important research problem in many diverse application areas. The filters we usually refer to are temporal filters, which pass the frequency components of interest and attenuate the others. A spatial filter passes the signal radiating from a specific location and attenuates signals from other locations. Beamformer that widely used in radar, sonar,and wireless communications is a kind of …     

The creation of a virtual NAG-algol 68 program library

A method for the creation of a virtual Algol 68 program library on top of a subset of the NAG-FORTRAN library is discussed.     

图书馆结构化综合布线系统的设计与实施

本文根据我校图书馆实际情况,详细介绍了有关结构化综合布线的设计等问题,并具体探讨了信息点的确定,布线系统的选择,以及施工和验收标准等。本文认为：结构化综合布线系统的设计与实施,必须以合理、适用、灵活为原则,并应考虑现在的需要和将来的发展。     

Coupling structure-based design with combinatorial chemistry: application of active site derived pharmacophores with informative library design

Protein structural information is combined with combinatorial library design in the following protocol. Active site maps are generated from protein structures. All possible 2-, 3- and 4-point pharmacophores are enumerated from the active site map and encoded as bit strings. The pharmacophores define a design space that can be used to select compounds using an informative library design tool. The method was evaluated against a collection of compounds assayed previously against a cyclin-dependent kinase target, CDK-2, starting with 23 X-ray co-crystal structures. Performance was assessed based on the number of active scaffolds selected after four rounds of iterative informative library design. The method selects compounds from 12 out of the 15 active scaffolds from the CDK-2 library and outperforms a two-dimensional similarity search and docking calculations.     

基于令牌的共享资源分配算法

通过对工业控制中多个设备共用一个设备问题的分析,提炼出一个更具一般性的控制问题-共享资源的分配问题。引用计算机局域网通讯中的令牌总线网工作原理,将其应用在共享资源的分配问题上。给出了用令牌原理解决该类共享资源分配的一般思路和算法。最后运用该算法举例解决了转炉投料系统中的集中称量问题。     

两种倍频方式的比较与设计研究

针对倍频电路进行了研究与设计。分别使用硬件倍频和FPGA倍频两种方式实现了对50Hz方波的两倍频,并对两种方式进行了比较研究。     

Integrated design of the feedback controller and topography estimator for atomic force microscopy

In atomic force microscopy (AFM) the force between the measurement tip and the sample is controlled in a feedback loop to prevent damage of the tip and sample during imaging, and to convert the measurement of the tip–sample force into an estimate of the sample topography. Dynamical uncertainties of the system limit the achievable control bandwidth and the accuracy of the topography estimation. This paper presents an integrated approach to design a feedback controller and topography estimator, taking into account the dynamical uncertainties of the system. The proposed methodology is experimentally demonstrated on a commercial AFM system, showing a direct trade-off between the control bandwidth and the accuracy of the topography estimation.     

基于Wiki的软件设计模式库的设计与实现

软件设计模式库的构建和模式复用是当前软件复用研究的热点,对提高软件开发效率和质量具有重要意义.通过将软件设计模式分类、描述和存储,建立模式库,为软件设计和开发提供支持.本文提出了模式库系统的管理流程和系统框架.分析了Wiki的特点,并结合其特点给出了基于Wiki的软件设计模式库的实现.     

Fuzzy multiple attributes group decision-making based on the ranking values and the arithmetic operations of interval type-2 fuzzy sets

In this paper, we present a new method to handle fuzzy multiple attributes group decision-making problems based on the ranking values and the arithmetic operations of interval type-2 fuzzy sets. First, we present the arithmetic operations between interval type-2 fuzzy sets. Then, we present a fuzzy ranking method to calculate the ranking values of interval type-2 fuzzy sets. We also make a comparison of the ranking values of the proposed method with the existing methods. Based on the proposed fuzzy ranking method and the proposed arithmetic operations between interval type-2 fuzzy sets, we present a new method to handle fuzzy multiple attributes group decision-making problems. The proposed method provides us with a useful way to handle fuzzy multiple attributes group decision-making problems in a more flexible and more intelligent manner due to the fact that it uses interval type-2 fuzzy sets rather than traditional type-1 fuzzy sets to represent the evaluating values and the weights of attributes.     

A framework for the design and verification of software measurement methods

At the core of any engineering discipline is the use of measures, based on ISO standards or on widely recognized conventions, for the development and analysis of the artifacts produced by engineers. In the software domain, many alternatives have been proposed to measure the same attributes, but there is no consensus on a framework for how to analyze or choose among these measures. Furthermore, there is often not even a consensus on the characteristics of the attributes to be measured.In this paper, a framework is proposed for a software measurement life cycle with a particular focus on the design phase of a software measure. The framework includes definitions of the verification criteria that can be used to understand the stages of software measurement design. This framework also integrates the different perspectives of existing measurement approaches. In addition to inputs from the software measurement literature the framework integrates the concepts and vocabulary of metrology. This metrological approach provides a clear definition of the concepts, as well as the activities and products, related to measurement. The aim is to give an integrated view, involving the practical side and the theoretical side, as well as the basic underlying concepts of measurement.     

The challenge of equality constraints in robust design optimization: examination and new approach

In recent years, robust design optimization (RDO) has emerged as a significant area of research. The focus of RDO is to obtain a design that minimizes the effects of uncertainty on product reliability and performance. The effectiveness of the resulting solution in RDO highly depends on how the objective function and the constraints are formulated to account for uncertainties. Inequality constraint and objective function formulations under uncertainty have been studied extensively in the literature. However, the approaches for formulating equality constraints in the RDO literature are in a state of disharmony. Moreover, we observe that these approaches are generally applicable only to certain special cases of equality constraints. There is a need for a systematic approach for handling equality constraints in RDO, which is the motivation for this research. In this paper, we examine critical issues pertinent to formulating equality constraints in RDO. Equality constraints in RDO can be classified as belonging to two classes: (1) those that cannot be satisfied, because of the uncertainty inherently present in the RDO problem, and (2) those that must be satisfied, regardless of the uncertainty present in the problem. In this paper, we propose a linearization- based approach to classify equality constraints into the above two classes, and propose respective formulation methods. The theoretical developments presented in this paper are illustrated with the help of two numerical examples.     

The design of an inter-task communication scheme

The paper describes an implemented inter-task communication scheme, and its design motivation. The scheme provides a well-defined environment for all situations, including abnormal ones, such as misuse of its facilities. The main design goal is that users of the scheme should be able to verify their communication logic by inspection. Methods are described for reducing the complexity of communication logic to a minimum. The analogy with inter-CPU communication is discussed.     

The specification of rank reducing observation sets in experimental design

If observations are lost from an experiment involving one or more forms of blocking, it can happen that the resultant design is treatment disconnected which has serious implications for the experiment. A method is described in this paper for specifying each set of observations which has the property that a treatment disconnected design will result if this observation set is missing. Some implications for two-replicate designs are described and four applications that portray the value of the method are discussed.     

单片机抗扰设计综述

对单片机应用系统的干扰源进行了分析,重点介绍了单片机系统中常用的硬件和软件抗干扰设计,并提出一种数字滤波全新算法,实时性很强,采用汇编语言来编写。