Communications software design for testability: specification transformations and testability measures

To deal with the increased complexity related to the testing of communications software, we propose the integration and application of finite state machine based specification transformations and testability measures early in the communications software development process. Based on this integration, the testability of a given design is estimated and appropriate specification transformations are defined and applied iteratively to enhance the testability of the product implementation.     

Calculation of probabilistic testability measures for digital circuits with Structurally Synthesized BDDs

A method is proposed for probabilistic testability analysis of digital circuits focusing on calculating the probabilistic controllability measures in terms of signal probabilities with the goal of assessment of pseudorandom test quality in digital circuits. The structure of the circuit is modeled as a macro-level network, where macros denote Fan-out-Free Regions (FFRs) of the circuit, which are represented as Structurally Synthesized BDDs (SSBDDs). SSBDD based representation allows signal probability calculation with higher speed and accuracy than using gate-level calculation approach. The proposed method is based on tracing true paths in SSBDDs, which avoids errors caused by signals' correlation and possible redundancy in the circuit, that is not possible in gate-by-gate probability calculation. A method is proposed for proving redundancy of faults, which is an extension of the same idea of SSBDD path tracing used for probability calculation. Experimental results show higher accuracy and considerable speed-up of probabilistic analysis using the proposed new macro-level approach, compared to gate-level calculation.     

粗糙函数依赖的近似度量

为了发现粗糙关系数据库中潜在的和有趣的模式,提出并研究了粗糙函数依赖的近似度量和精确度量。首先,对于关系数据库的近似度量及其满足的性质进行了研究,在此基础上提出了粗糙关系数据库（Rough Relational Database,简称RRDB）的近似度量及精确度量,对该两种度量进行了形式化定义,并且进一步研究了他所满足的性质,给出了相应的实例。该度量的提出及其性质的研究有利于粗糙关系数据库的知识发现及数据查询的研究,并且进一步扩大了粗糙关系数据库的研究领域。     

因子分解二终端网络可靠度近似计算

因子分解算法可以用来计算网络可靠度精确值,但对于大型网络,可靠度精确值的计算非常困难。基于时间和精确度的双重考虑,在精确算法的基础上通过改进得出一种近似算法。实验结果证明,该算法得到的近似值接近精确值,而且计算时间要低于精确算法。     

MBSE模式下可靠性安全性测试性一体化建模与评估技术方法

随着智能保障、PHM等技术不断深入应用,可靠性、安全性、测试性(以下简称"三性")的重要性日益凸显,工程中迫切需要解决"三性"重复工作、专业孤岛以及"两张皮"现象;从系统工程出发,首先分析了"三性"主线工作内容,均紧紧围绕功能故障逻辑关系开展,统一建模,实现模型复用;其次,在功能模型基础上映射出故障逻辑关系,更接近故障传递的真实情况,解决"两张皮"现象;然后,全面分析"三性"建模要素和评估内容,对专用部分的信息进行处理,使得"三性"工作不再是孤岛;最后,以燃油系统为例展开了建模评估,基于功能故障逻辑模型,分别进行了可靠性、安全性、测试性建模与评估,实现了模型复用,减少重复工作;专业协同工作,提高了工作效率;紧密结合功能,有效解决"两张皮"现象.     

Designing for testability

In the laboratory, a designer may conveniently analyse microprocessor circuits and their peripherals by means of suitable logic analysers. This is possible because he will have a detailed knowledge of his system and the time to learn the optimum methods of using his analyser. Once this system is a part of a product, it would be preferable if a less complicated means of verifying the processor's correct activity were available should a failure occur. An extremely convenient and inexpensive verification and diagnostic system may be designed into a product using two complementary techniques, selftest and signature analysis. The material cost of implementing such a system can be very small indeed whereas the savings in troubleshooting time and test equipment costs can be substantial.     

The Methodology of Testability Prediction for Sequential Circuits

Increasingly,test generation algorithms are being developed with the continuous creations of incredibly sophisticated computing systems.Of all the developments of testable as well as reliable designs for computing systems,the test generation for sequential circuits is usually viewed as one of the hard nuts to be solved for its complexity and time-consuming issue.Although dozens of algorithms have been proposed to cope with this issue,it still remains much to be desired in solving such problems as to determin 1) which of the existing test generation algorithms could be the most efficient for some particular circuits(by efficiency,we mean the Fault Coverage the algorithm offers,CPU time when executing,the number of test patterns to be applied,ectc.)since different algorithms would be preferable for different circuits;2)which parameters(such as the number of gates,flip-flops and loops,etc., in the circuit)will have the most or least influences on test generation so that the designers of circuits can have a global understanding during the stage of designing for testability.Testability forecastin methodology for the sequential circuits using regression models is presented which a user usually needs for analyzing his own circuits and selecting the most suitable test generation algorithm from all possible algorithms available.Some examples and experiment results are also provided in order to show how helpful and practical the method is.     

复杂系统可靠性多级综合的熵法第二近似限

根据信息量相等的原理，将部件或分系统的试验信息折合为产品的等效试验信息，导出指出寿命型系统的部件或分系统试验信息等效折合的基本公式，根据单元可靠性评定的基本理论，给出院 基于信息理论的复杂系统可靠性第二近似限的基本模型。计算实例说明了模型的具体应用，并与传统方法的评定结果进行比较，说明了模型的正确性和实用性。     

Optimization of testability parameters

The main objective of this study was to investigate performance models of automatic diagnostic systems taking into consideration its imperfections such as incorrect isolation and false alarms. This was accomplished by developing an optimization model to assist the decision maker in determining the optimal values of testability parameters which maximize his/her utility function. This will provide the decision maker with a tool to evaluate the parameters set forth by the designer and to assess the real capability of the diagnostic system. This tool also will help the decision maker to check if the correct detection and isolation capability of the system, as well as the imperfections of the system, e.g., incorrect isolation and false alarms are acceptable and satisfactory.

An interactive program was developed and help to implement the optimization modedl. This program provides the decision maker with enough flexibility to avaluate different different strategies and to repeat the decision process after changing one or more of the model's parameter. An example will be presented to show the application of this optimization model.     

Reconvergent-Fanout-Oriented Testability Measure

This paper describes the theory and implementation of a testability measure program called RFOTM.Itis suggested that the real difficulty in test generation should be reflected in testability measure.We analysethe behavior of fanout and reconvergent fanout which cause inconsistency in generating tests.Aclassification of fanouts is given and a class of fanouts which behaves like fanout-free lines is described.Based on this observation,the new measure is developed with emphasis on the influence of fanout andreconvergent fanout,and is shown with more accurate prdiction for testing difficulty and acceptablecomputing complexity.     

Integrating testability into microsystems

 The integration of sensors and actuators with microelectronics into either compact packages or onto a single silicon die is likely to be of major technological importance over the next decade. These systems are referred to as Microsystems or Micro-Electro-Mechanical-Systems (MEMS). One obstacle to mass-market introduction are difficulties with quality and reliability verification. This paper outlines the difficulties of testing microsystems, shows approaches of test generation and verification transferable from the mixed-signal Integrated-Circuit (IC) domain, and demonstrates an on-line test designed for bridge-type, micromachined accelerometer and pressure sensors [1]. Received: 31 October 1996 / Accepted: 14 November 1996     

An approximate sequential optimization and reliability assessment method for reliability-based design optimization

Sequential optimization and reliability assessment (SORA) is one of the most popular decoupled approaches to solve reliability-based design optimization (RBDO) problem because of its efficiency and robustness. In SORA, the double loop structure is decoupled through a serial of cycles of deterministic optimization and reliability assessment. In each cycle, the deterministic optimization and reliability assessment are performed sequentially and the boundaries of violated constraints are shifted to the feasible direction according to the reliability information obtained in the previous cycle. In this paper, based on the concept of SORA, approximate most probable target point (MPTP) and approximate probabilistic performance measure (PPM) are adopted in reliability assessment. In each cycle, the approximate MPTP needs to be reserved, which will be used to obtain new approximate MPTP in the next cycle. There is no need to evaluate the performance function in the deterministic optimization since the approximate PPM and its sensitivity are used to formulate the linear Taylor expansion of the constraint function. One example is used to illustrate that the approximate MPTP will approach the accurate MPTP with the iteration. The design variables and the approximate MPTP converge simultaneously. Numerical results of several examples indicate the proposed method is robust and more efficient than SORA and other common RBDO methods.     

The reliability and stability of various individual difference and tolerance to shiftwork measures

The aim of the study was to evaluate the reliability and temporal stability of various individual difference and tolerance to shiftwork measures which were used in an extensive study on relationships between shiftworkers' features and tolerance to shiftwork. The study was conducted in a Croatian oil refinery where 604 male shift workers, working in a 2:2:3 continuous three-shift system were examined by means of various questionnaires. A subsample of 61 shift workers were re-examined using the same questionnaires and the same administration procedure nine years later. The questionnaires were: Jenkins Activity Survey, Eysenck Personality Inventory, Momingness-Eveningness Questionnaire, Behavioural Arousal Questionnaire, Orcadian Type Questionnaire and Inventory, Way of Life Questionnaire, Health Information Questionnaire, Sleep Quality Scale. The questionnaires were scored for 14 individual difference measures and eight tolerance to shiftwork measures. In addition to these scores sleep durations on night, morning, afternoon shifts, and on days off were used as tolerance to shiftwork measures. The reliability of each measure was determined by means of Cronbach alpha coefficients computed on a total of 604 shiftworkers and temporal stability by means of correlation coefficients between the scores obtained on two occasions on the subsample of 61 shiftworkers. The internal consistency coefficients for most of the measures ranged between moderate to high, and were considered to be satisfactory. The correlations between the scores obtained twice over a period of nine years proved both the individual difference and tolerance to shiftwork measures to be temporally stable. The only measure that had insignificant correlation was the sleep duration on days off.     

机载设备测试性建模与应用

测试性模型是进行测试性仿真、设计、分析、评估的基础和关键。该文描述了设备测试性建模方法与测试性建模流程,为实现对复杂系统的测试性分析及故障诊断,获取有指导意义的诊断策略服务实际应用。测试性设计中采用多信号流建模技术,分层次建立某型机载音频设备的测试性模型;对设备故障模式、故障影响的分析归纳,收集各层级设备故障模式样本形成FMEA分析表;运用计算机建模仿真工具辅助,构建了定量化的测试性模型;通过模型仿真获得被测设备故障检测率、隔离率以及相关故障诊断流程;经测试性指标对比分析及测试性试验验证,发现该测试性模型中薄弱环节,经过迭代模型、改进测试性方案后,显著提高了设备的测试性指标,满足设备的应用使用需求。     

位模式下粗糙函数依赖近似度量的研究

利用粒计算位模式方法对粗糙关系数据库（Rough Relational Database,RRDB）的粗糙函数依赖的度量问题进行研究。首先对粗糙函数依赖、RRDB中粗糙上下近似进行了分析,然后利用位模式表示粗糙关系的属性值,在此基础上给出了位模式利用粒计算方法对粗糙函数依赖进行度量的模型,并研究了其满足的性质。     

基于数字孪生的测试性验证技术

针对型号测试性验证工作中存在的验证周期长、验证时机滞后、验证环境受限等问题,开展了基于数字孪生技术的测试性验证技术研究,重点关注数字孪生技术框架和关键技术研究,包括基于数字孪生驱动的故障模式分析、基于数字孪生驱动的故障模式空间模拟、基于数字孪生驱动的故障模式分配与注入、基于数字孪生驱动的数据融合技术,以期实现装备全生命周期的测试性验证与增长。形成一套基于数字孪生驱动的测试性验证流程及方法,用于指导新研产品的测试性验证工作。     

BDI agent testability revisited

Agent-based systems are deployed to solve a wide range of problems in a wide range of domains. Before software is deployed, it is important to obtain assurance that it will function correctly. Traditionally, this assurance is obtained by testing. However, there is an intuition that agents exhibit more complex behaviour than traditional software, which raises the question: how testable are agent systems? We focus on BDI agent programs, and analyse their testability with respect to the all edges test adequacy criterion (also known as “branch coverage”). Our results augment earlier results that considered the all paths criterion to provide a richer and more nuanced understanding of the testability of BDI agents. We show that the number of tests required with respect to the all edges criterion is much lower than that required with respect to the all paths criterion. We also show that, as for the previous analysis, BDI programs are harder to test than equivalently-sized procedural programs, even if exception handling is introduced. Overall, our conclusions lend strength to the earlier work, and motivate the need for work on formal methods for agent systems.     

基于云模型的可信软件可靠性度量模型

针对可信软件可靠性定性评估问题,将云模型理论与GB/T16260中软件可靠性度量指标相结合,提出了一种基于云模型的软件可靠性度量模型.模型根据可靠性度量指标提取样本信息,通过云发生器生成云模型,运用合并云算法将多个属性云合并为一个综合云模型,使用带权重的欧氏距离云决策算法确定综合云模型的可靠性等级.通过某安全关键软件验证,该模型能够更加客观、真实地反映软件的可靠性.     

Alpha 21164 testability strategy

A custom DFT strategy solved specific testability and manufacturing issues for this high performance microprocessor. Hardware and software assisted self test and self repair features helped meet aggressive schedule and manufacturing quality and cost goals