Evaluation of functions on microcomputers: exp(x)

This paper is a continuation of a study of numerical software for evaluating elementary functions in a microcomputer environment. Here we describe three algorithms for evaluation of the exponential function that are based on rationals, polynomials and coarse table look-up, respectively. Focus is on the design of fast algorithms that preserve full machine precision in small scale machines which use truncated binary fixed point arithmetic with at most a sixteen-bit wordlength. Included in the paper is a comparison of the performance of these algorithms implemented in two contemporary microcomputers.     

基于UML的软件体系结构的定量评估

软件体系结构是软件开发过程的关键制品,应该尽早地分析和评估其质量.目前研究的软件体系结构评估主要集中在基于场景的评估方法,其特点是定性的、主观的、无需专用的体系结构描述语言.本文提出以统一建模语言UML作为软件体系结构描述语言以及度量的软件体系结构的定量评估.针对UML的可视化、多视图、半形式化以及一致地应用在整个软件开发活动的特性,提出一组UML度量,从UML图所表达的信息含量、可视化影响以及图形建模元素之间的关联性这三个方面度量软件体系结构.分析并讨论这组UML度量在评估软件体系结构的规模、复杂性和结构性等质量属性方面的应用.     

BCL-3: A High Performance Basic Communication Protocol for Commodity Superserver DAWNING-3000

1 IntroductionC1usters have been popu1ar platforms fOr high performance computing in receot years. They arewidely used in scientific and engineering computing business computing, and Internet informationservices. Communication perfOrmance is one of the most critical factors determining the perfOrmanceof a whole cluster system. So how to improve the performance of communication is a hot researchtopic in cluster computing. Meanwhile, bui1ding a cluster with commodity SMPs (CLUMPS) isbecorn…     

A software tool for performance evaluation of digital control algorithms on finite wordlength processors

A large number of algorithms exist for digital control which work well with high precision floating point computation. When implemented in finite wordlength processors without inherent floating point capability, these control algorithms often fail to demonstrate their effectiveness. The software described here has been developed to test the performance of digital controllers under such finite wordlength situations. It is also shown, how, with a suitable restructuring of the conventional discrete-time shift operator models, considerably improved robustness to such situations can be achieved with marginally added computations.     

Consequences of the digitization on the performance of a fuzzylogic controller

The consequences of the finite wordlength on the performance of a digital fuzzy logic controller (FLC) based on Mamdani's inference algorithm are investigated. Digital implementations of FLCs involve three main types of errors due to the finiteness of the wordlength: analog-to-digital errors, membership function errors, and arithmetic errors. First, a statistical evaluation of the consequences of these errors is performed. The effects of the digital resolution on the controller response are discussed. Then, the dynamic behavior of a closed-loop fuzzy system composed of a digitized FLC and a second-order plant is evaluated; a qualitative evaluation of time-domain parameters as a function of the universe discretization is carried out. The results show that, as in the case of conventional control strategies, bias effects and limit cycles are generated as a consequence of the digitization. Although these distortions diminish when the discretization is sufficiently refined, they are very difficult to predict because of the nonlinear nature of both quantization and fuzzy operation. In this sense, the availability of computer-aided design (CAD) tools that permit the specification of the wordlength is essential to validate the design     

软件可信评估模型及其工具实现

软件可信评估是软件质量保障的一项重要内容。现有软件可信评估研究存在适用的软件形态单一、评估的可信属性固定、缺乏具体的评估工具等不足。因此,提出了一种通用的软件可信评估模型,系统地讨论了模型的实现过程,开发了一个可信评估管理系统,通过对一个税务领域案例的详细分析,验证了模型实施的可行性。该研究及评估工具能有效辅助软件可信评估活动的实施,指导软件质量的改进。     

Informal feedback rather than performance measurements – user-centred evaluation in Scrum projects

The main features of the Scrum process are intense communication between different stakeholders, and rapid feedback based on regular delivery of working software. The integration of traditional user-centred evaluation activities in this context is challenging. Hence, this paper presents an interview study of 21 informants, categorised in four different professional roles. The main contribution of the paper is an overview of the types of user-centred evaluation conducted by information technology professionals in various Scrum projects. Results show that various forms of feedback are indeed gathered on the usability and user experience of the software, system or service being developed. However, the user-centred evaluations conducted typically are informal with few users, gathering empirical qualitative data and performed during short unplanned sessions. Performance measurements gathering quantitative data are seldom used. The informants in the business specialist role merely ask users about their opinion, whereas the other roles use several user-centred evaluation activities to gather feedback on their design. Generally, feedback is gathered throughout the whole project, but often evaluation is conducted early in the project or even before the actual development starts. Finally, these results are discussed in relation to previous studies in the area.     

基于定点DSP的浮点开平方算法的实现

本文提出了基于TMS320C2XX定点DSP的浮点开平方算法，给出了实现方法及程序清单，实践证明该方法具有精度高，运算速度快、程序简单等特点。     

北斗短报文与固定电话语音 通讯服务系统设计

北斗三号系统已于2018年12月完成建设,并开始提供全球服务,北斗短报文应用也即将覆盖全球。由于一些特殊环境并没有北斗系统专用的接收机,配备接收机也很不方便,为了使通信联络正常,基于北斗一号用户机数据接口2.1协议,以STM32系列单片机为数据处理单元,重点从系统硬件、软件两部分入手,对北斗短报文与固定电话语音通讯服务系统进行了研究与设计。该系统利用北斗电话网关实现北斗短报文与固话座机或移动电话的互联互通,解决了在没有接收机的特殊环境或者不使用接收机的情况下,无法进行正常通信联络问题,以及基于北斗短报文通信的安全性、可靠性、局限性问题,同时扩展了北斗短报文的通信应用范围。     

软件体系结构性能评价研究

1 引言随着软件规模和复杂程度不断地扩大和增加,软件开发的成败已不再完全取决于数据结构和软件算法的选择,而是在很大程度上取决于软件系统体系结构(Software Architecture)的设计。软件体系结构已经成为一个新兴的计算机学科。所谓的软件体系结构是问题解决方案的逻辑框架,它包括系统中各计算单元(组件)的功能分配、各单元间的高层交     

整数开平方快速算法及其定点DSP实现

本文提出了基于ADSP-BF533定点DSP的整数开平方快速算法,给出了C语言及其汇编实现。实践证明该方法具有精度高、运算速度快、程序简单等特点。     

支持软件可信评估的框架及其应用研究

软件可信评估是软件可信研究的一个重要方面,但是目前已有的研究存在适用的软件形态受限、评估的可信属性不全面、未提供具体的应用实现等不足。针对上述问题,通过对已有相关工作进行改进和扩展,提出了一种通用的软件可信评估框架,阐述了应用该框架实现可信评估的具体过程,给出了详尽的案例分析,并基于该框架开发了可信评估管理系统,验证了框架实施的可行性。实验表明此项研究适用于不同形态的软件,支持可信属性、可信证据、评估指标的定制,对于软件可信评估活动的成功实施具有一定的指导作用。     

基于Agent的软件可靠性评估系统

1 引言现代软件产品的重要特征之一是软件质量,而软件可靠性被认为是软件质量的关键因素。软件可靠性指软件在特定环境和给定时间内无故障运行的概率。它面向用户而不是开发者,是软件质量诸多因素中最容易度量的属性。软件可靠性模型是随机过程的一种表示,可以将软件可靠性或与其直接有关的量(如平均无故障时间或故障率)表示成时间以及软件产品     

Contextual Method for the Redesign of Existing Software Products

Abstract

This article is concerned with the problem of improving software products and investigates how to base that process on solid empirical foundations. Our key contribution is a contextual method that provides a means of identifying new features to support discovered and currently unsupported ways of working and a means of evaluating the usefulness of proposed features. Standard methods of discovery and evaluation, such as interviews and usability testing, gather some of the necessary data but fall short of covering important aspects. The shortcomings of these approaches are overcome by applying an integrated and iterative method for collecting and interpreting data about product usage in context. This article demonstrates its effectiveness when applied to the discovery and evaluation of new features for standard Web clients.     

Efficiency of CAMEtools in software quality assurance

Our paper describes the requirements and possibilities of integration of metrics tools in the field of software quality assurance. Tools for the support of the measurement process are herein classified as Computer Assisted Software Measurement and Evaulation Tools (CAMETools). Software measurement regarded as a special type of metrics application provides a great amount of basic information for the evaluation of the software development process or the software product itself. Our paper examines the effectiveness and destination of software measurement in tool-based software development and is based on an analysis of more than 20 CAME tools in the Software Measurement Laboratory at the University of Magdeburg. CAMEtools are useable for the process, product, and resources evaluation in all phases of the software life cycle (including the problem definition) for different development paradigms. The efficiency of CAME tools is described on the basis of a general measurement framework. This framework includes all steps in the software measurement and evaulation process: metrics definition, selection of the evaluation criteria, tool-based modelling and measurement, value presentation and statistical analysis. The framework includes the main aspects of the process evaluation techniques (Capability Maturity Model, ISO 9000-3 etc.) and product evaluation (ISO 9126, etc.). It is not a disjointed set of aspects: our measurement framework represents an incremental technique for the application of quantification of quality aspects in a required quality assurance     

Parametric spline curves in integer arithmetic designed for use in microcomputer controlled plotters

An algorithm for generating a parametric spline curve through a set of points using only integer arithmetic is derived. The algorithm is especially suited for implementation on simple computers with a short wordlength and does not require multiplication or division. It is an incremental step algorithm suited for digital plotting and numerical machine tool control. It has been used to draw optimally “nice” alphanumeric characters independent of scale in a plotting system for the RC4000 computer where a microcomputer controls the plotter. The splined alphanumeric characters do not require more computer time on the main processor than the simple characters using straight line segments, and only increases the load on the microcomputer.     

蚁群模拟退火算法在测试用例约简中的应用

参数的成对组合覆盖测试技术是软件测试中有效的测试方法之一。该文将模拟退火思想引入蚁群算法,组成新的混合算法,即蚁群模拟退火混合算法(ASA),应用在组合测试用例的约简过程中。按照测试的特殊需求进行多种建模尝试,通过仿真实验对算法涉及的参数进行研究,实验验证了ASA 算法对测试用例集的约简作用是有效的。