Robust optimal experiment design for system identification

This paper develops the idea of min-max robust experiment design for dynamic system identification. The idea of min-max experiment design has been explored in the statistics literature. However, the technique is virtually unknown by the engineering community and, accordingly, there has been little prior work on examining its properties when applied to dynamic system identification. This paper initiates an exploration of these ideas. The paper considers linear systems with energy (or power) bounded inputs. We assume that the parameters lie in a given compact set and optimise the worst case over this set. We also provide a detailed analysis of the solution for an illustrative one parameter example and propose a convex optimisation algorithm that can be applied more generally to a discretised approximation to the design problem. We also examine the role played by different design criteria and present a simulation example illustrating the merits of the proposed approach.     

最优实验设计的改进随机进化算法

详细阐述构造最优实验设计的原始随机进化算法,并在原始算法的基础上,拓展广度搜索,改进深度搜索,以提高最优实验设计的计算速度。通过不同规模和不同优化准则的拉丁超立方体最优实验设计,验证改进算法的应用效果。算例分析表明,改进算法能够比原始算法节省约30%～60%的机时完成最优实验设计,而且改进算法对应于优化准则的最优值与原始算法最优值的差别仅为1%～3%。可见,改进算法能够兼顾最优实验设计的计算时间和优化质量,明显提高最优实验设计的构造效率。     

基于正交法的软件测试用例生成

在软件测试中,即使对中小规模的软件,要想达到一定的测试覆盖要求,生成的测试用例数目都可能非常惊人.为了尽早地产生高质量的测试数据,将有限的测试资源进行合理的分配,提出了一种基于正交试验设计法(简称正交法)的软件测试用例生成技术.介绍了正交法的基本概念和主要用途,详细阐述了运用正交法进行软件测试用例设计的步骤,最后将其应用于一个简易管理信息系统,结果表明,生成的测试数据数量较少且错误检测能力较高.     

半实物仿真中试验总控软件的设计与实现

试验总控软件是应用于半实物仿真中对参试系统进行管理和控制的一种软件,它可以对半实物仿真中的参试系统进行配置,实现对整个试验仿真的管理和监控。解析各参试系统的数据交互协议是试验总控软件对参试系统进行监控和管理的关键功能。通常试验总控软件解析功能代码完全按照各参试系统数据交互协议开发,这样一旦数据交互协议发生更改,解析功能代码需要根据新协议重新开发导致软件重复开发,影响软件开发效率和通用性。为了解决这个问题,文中提出一种试验总控软件设计框架并采用动态解析数据帧技术将解析代码与数据交互协议隔离,不仅提高软件通用性,同时缩短半实物仿真开发周期,减少人力财力开支。     

Finding the optimal parameters for a software reliability model

Failure rate parameters exert a great deal of influence on the accuracy of software reliability predictions. Thus, it behooves us to examine the methods that are used to estimate the parameters. The value of parameters is determined by the pattern of historical failure data and the amount of data used in the estimates. Conventional wisdom suggests that all the data be used. However, this could be counterproductive if all the data are not representative of the current and future failure process. Therefore, we can analyze these factors to obtain the optimal parameter estimates, where “optimal” means parameter values that will result in minimum prediction error. We examine one software reliability model that does not use all the failure data if a priori analysis indicates that optimal parameter values could not be obtained. Historically, this model has used a mean square error criterion (MSE) of the difference between actual and predicted reliability in the parameter estimation range. However, it has been observed that this policy does not always result in minimum error predictions in the prediction range. Therefore, we investigated the linear interpolation estimation method as an alternative to MSE for three NASA shuttle flight software releases comprising forty-two reliability predictions. Interestingly, linear interpolation provided better prediction accuracy, overall. We believe our analysis can be applied to other software and failure data. In order to systematize our thinking on developing new models using linear interpolation, we employed object-oriented design concepts as guides to implementing C++ programs for evaluating linear interpolation with respect to MSE. The author is a fellow of the IEEE, an IEEE Congressional Fellow, and a member of the US Senate 2005.     

基于正交试验设计的软件操作剖面构造方法

为了解决传统的操作数量控制方法中出现的问题,提出一种基于正交试验设计的软件操作剖面构造方法.该方法首先确定操作额定值,接着建立一个粗略的操作剖面,然后在一些粗略操作对应的多属性区域内通过比较发生概率和正交试验设计等方法选取新的操作,最后整理操作及发生概率,得到最终的操作剖面.应用该方法能够开发出满足要求的操作剖面,并分析指出了该方法的优越性.     

On the development of software support for solving problems of optimal design of power boilers

Power boilers are complicated technical objects consisting of a large number of interconnected components. Main problems of creating mathematical models and software support for optimal design of power boiler units are analyzed, approaches to the solution of them are described, and distinctive features of their software implementation are considered. Results of testing software are considered.     

Resampling-based software for estimating optimal sample size

The SISSI program implements a novel approach for the estimation of the optimal sample size in experimental data collection. It provides a visual evaluation system of sample size determination, derived from a resampling-based procedure (namely, jackknife). The approach is based on intensive use of the sample data by systematically taking sub-samples of the original data set, and calculating mean and standard deviation for each of sub-samples. This approach overcomes the typical limitations of conventional methods, requiring data-matching statistical assumptions. Visual, easy-to-interpret provisions are supplied to display the variation of means and standard deviations as size of generated samples increases. An automatic option for identification of optimal sample size is given, targeted at the size for which the rate of change of means becomes negligible. Alternatively, a manual option can be applied. An ideal application of SISSI is in supporting the collection of plant and soil samples from field-grown crops, but it also holds potential for more general application. SISSI is developed in Visual Basic and runs under the Windows operating systems. The installation software package includes the executable files and a hypertext help file. SISSI is freely available for non-profit applications.     

Estimating parameters with pre-specified accuracies in distributed parameter systems using optimal experiment design

Estimation of physical parameters in dynamical systems driven by linear partial differential equations is an important problem. In this paper, we introduce the least costly experiment design framework for these systems. It enables parameter estimation with an accuracy that is specified by the experimenter prior to the identification experiment, while at the same time minimising the cost of the experiment. We show how to adapt the classical framework for these systems and take into account scaling and stability issues. We also introduce a progressive subdivision algorithm that further generalises the experiment design framework in the sense that it returns the lowest cost by finding the optimal input signal, and optimal sensor and actuator locations. Our methodology is then applied to a relevant problem in heat transfer studies: estimation of conductivity and diffusivity parameters in front-face experiments. We find good correspondence between numerical and theoretical results.     

The optimal class size for object-oriented software

A growing body of literature suggests that there is an optimal size for software components. This means that components that are too small or too big will have a higher defect content (i.e., there is a U-shaped curve relating defect content to size). The U-shaped curve has become known as the "Goldilocks Conjecture." Recently, a cognitive theory has been proposed to explain this phenomenon and it has been expanded to characterize object-oriented software. This conjecture has wide implications for software engineering practice. It suggests 1) that designers should deliberately strive to design classes that are of the optimal size, 2) that program decomposition is harmful, and 3) that there exists a maximum (threshold) class size that should not be exceeded to ensure fewer faults in the software. The purpose of the current paper is to evaluate this conjecture for object-oriented systems. We first demonstrate that the claims of an optimal component/class size (1) above) and of smaller components/classes having a greater defect content (2) above) are due to a mathematical artifact in the analyses performed previously. We then empirically test the threshold effect claims of this conjecture (3) above). To our knowledge, the empirical test of size threshold effects for object-oriented systems has not been performed thus far. We performed an initial study with an industrial C++ system and repeated it twice on another C++ system and on a commercial Java application. Our results provide unambiguous evidence that there is no threshold effect of class size. We obtained the same result for three systems using four different size measures. These findings suggest that there is a simple continuous relationship between class size and faults, and that, optimal class size, smaller classes are better and threshold effects conjectures have no sound theoretical nor empirical basis     

化工原理实验数据处理软件的开发

本软件旨在解决通常的化工原理实验数据处理过程中或因计算复杂,或因作图时不可避免的出错而影响实验结果的问题.它以Visual Basic 6.0为开发工具,采用最小二乘法直线拟合、非线性拟合、数值积分等方法处理实验数据,可完全消除学生作图出错,使实验结果更正确、更科学.本软件为处理化工原理实验数据提供方便、快捷的方法,也为教师批改实验报告提供可靠的依据.该软件在中文Windows环境中运行,界面美观、操作方便.     

Behavior specification in a software design system

A technique for software system behavior specification appropriate for use in designing systems with concurrency is presented. The technique is based upon a generalized ability to define events, or significant occurrences in a software system, and then indicate whatever constraints the designer might wish to see imposed upon the ordering or simultaneity of those events. Constructs implementing this technique in the DREAM software design system are presented and illustrated. The relationship of this technique to other behavior specification techniques is also discussed.     

A program for individual and population optimal design for univariate and multivariate response pharmacokinetic-pharmacodynamic models

The design of pharmacokinetic and pharmacodynamic experiments concerns a number of issues, among which are the number of observations and the times when they are taken. Often a model is used to describe these data and the pharmacokinetic-pharmacodynamic behavior of a drug. Knowledge of the data analysis model at the design stage is beneficial for collecting patient data for parameter estimation. A number of criteria for model-oriented experiments, which maximize the information content of the data, are available. In this paper we present a program, Popdes, to investigate the D-optimal design of individual and population multivariate response models, such as pharmacokinetic-pharmacodynamic, physiologically based pharmacokinetic, and parent drug and metabolites models. A pre-clinical and clinical pharmacokinetic-pharmacodynamic model describing the concentration-time profile and effect of an oncology compound in development is used for illustration.     

A design medium for software

A design medium for software is proposed and illustrated. The medium, which employs rectangular, embedded contours, provides a high level of scale independence. Module specifications, logic design and program elements are easily intermixed in a design. The proposed module formalization includes interface specification, exceptions, logic design and effects in an order which will ultimately be exhibited by the program code as well.     

CAL software design for transferability

The successful transfer of CAL software is often thwarted by differences between the computer system on which the software was developed and that on which it is required to be implemented. Facilities which CAL programs may exploit are usually those most vulnerable to change between different computer systems.Drawing upon experience gained in the design, programming, and subsequent transfer of CAL programs in engineering, examples are given of features which may cause problems during implementation and alternatives or improvements are suggested. FORTRAN and GINO-F are proposed as machine and device independent standards, for implementation language and graphics subroutine library, respectively.Good programming practices are described with a view to obtaining readable and easily maintained programs of a sound quality. Importance is placed on modularity in design as the key to writing transportable programs. The idea that every module should conceal some design decisions from all other modules is described with reference to modules that have proved to be particularly useful or advisable. This technique enables a design to be produced in which machine dependencies and difficult design decisions may be confined to a handful of routines. This makes the program more adaptable and gives the teacher and programmer greater freedom to change the implementation, allowing the program to move to any computer system where similar functions can be implemented.     

An experiment in concurrent software evaluation

This paper considers a method for evaluating the concurrent programming language available on a multiprocessor system – in particular, a shared-memory multiprocessor system. The method is based on the consideration of well-known algorithms which have been used as a means of demonstrating the expressive power of new concurrent language constructs. The algorithms considered are the Readers and Writers Problem and the Drinking Philosophers Problem. Both algorithms are coded using features that are widely regarded as being state-of-the-art for shared-memory systems and are then recoded in the language available on an actual multiprocessor system in order to carry out a comparison and evaluation. Several observations and conclusions are drawn.