基于单元故障模型的树型加法器的测试

首先分析了树型加法器的原理，总结了其运算特性．其次在介绍单元故障模型的基础上分析了树型加法器的测试向量生成．分析结果表明，5n-1个测试向量可以实现树型加法器中所有单元故障的检测．这些测试向量具有很好的规则性，能够利用片上测试向量生成器实现，适合于应用内建自测试技术测试．基于此，作者提出了一种内建自测试的测试结构，测试时只需存储7个籽测试向量，其它测试向量可以在这7个籽测试向量的基础上通过循环移位实现．最后给出了实验分析结果．     

基于ASAAC标准的BIT设计

为满足航空电子系统的可测试性,降低航空电子系统测试维护成本,结合ASAAC标准设计一个机内自测试(BIT)系统。BIT利用自身资源对系统进行故障检测或隔离,采用总线层次化方法将BIT设计分为系统级、分系统级及模块级3层测试结构,并给出模块级测试的软硬件设计方案。测试结果表明,该系统能使测试与航电系统的健康管理和故障管理紧密结合,在满足测试覆盖率等技术指标的同时,提高航空电子系统可靠性与可测试性。     

SPARC体系结构处理器测试方法研究与实现

处理器离线测试广泛采用随机测试技术,但是随机测试技术生成大量测试代码,并且测试覆盖率不高;主要针对随机测试的不足,借鉴基于软件内建自测试方法建立处理器模块级于系统级功能模型,后分析功能模型可能发生错误,针对错误模型开发测试代码来提高错误覆盖率;经测试,模块级测试覆盖到所有功能点,达到功能模块100%测试,系统级的测试覆盖到SPARC V8的所有指令异常、正常测试用例;测试结果表明,所采取的测试方案对提高错误覆盖率是行之有效的.     

基于确定性测试图形的BIST构建方法

为降低内建自测试(Build-in Self Test,BIST)的测试功耗,提出了一种基于确定性测试图形的内建自测试构建方法:首先采用D算法生成测试所需的测试图形,然后使用粒子群算法对其进行优化,使内建自测试的功耗大幅度降低;文中最后以ISCAS'85Benchmark中的部分电路作为实验对象,并给出了测试图形优化前后的功耗数;实验结果证明该方法能够有效降低内建自测试的测试功耗,并且具有方法简单、无需额外硬件开销的特点.     

系统芯片IP核间互联总线串扰故障检测模型的BIST实现

文章针对系统芯片IP核间互联总线串扰故障的激励检测问题,在已经提出一种有效的串扰故障渐进式激励检测模型的基础上,给出了一种该渐进式模型的内建自测试(BIST)实现,对其中的测试矢量产生单元、测试响应分析单元以及测试控制单元进行了详细的分析。同时还给出了该BIST结构实现的参数化HDL描述,文章的最后给出了使用综合工具Synopsys对该BIST结构的综合结果。     

一种组合电路内建自测试的改进方法

对组合电路的测试提出了一种将确定性测试生成方法与内建自测试相结合的设计方案;设计实现了利用D算法生成的测试矢量和伪随机测试序列生成电路共同构成测试矢量生成模块,利用内建自测试方法完成可测性设计,并将两者结合得出组合电路内建自测试的改进方法;分析与实验结果表明,该方法能减少系统硬件占用,同时具有测试向量少、故障覆盖率高的特点。     

手机电磁干扰测试系统研究与实现

参照手机测试标准,全面分析了进行手机EMI测试系统设计时需要考虑的因素和应对策略,然后给出了一套自测试系统的设计方案,该方案在满足标准要求的基础上采用虚拟置换法对辐射杂散骚扰测试进行了优化设计,缩短了项测试时间,提高了系统性价比。     

硬件复用的内建自测试结构设计

现代数字集成电路因规模庞大而导致测试困难,内建自测试是一种有效的可测性设计技术;由于内建自测试在电路内部设计测试生成与分析模块,需要消耗额外的硬件资源;通过对测试生成与特征分析模块的结构分析,提出基于硬件结构复用的可重构逻辑块观测器,并基于该模块设计了可重构的内建自测试结构;仿真结果表明,该测试结构通过硬件结构的时分复用,能有效地降低硬件资源消耗,测试逻辑正确有效,测试速度较快。     

基于FPGA的板级BIST设计和实现策略

为解决复杂电路板的测试问题,边界扫描、内建自测试等可测性设计技术相继发展,针对目前板级可测性设计发展状况,提出了基于FPGA的板级BIST设计策略;通过阐述存储器模块、逻辑模块和模拟模块三大部分的BIST设计,说明了基于FPGA进行板级模块BIST设计的灵活性和优势;最后,给出了在FPGA内构建BIST控制器的方法,并介绍了FPGA自测试的实现以及在板级设计过程中要考虑的问题。     

Flash存储器的内建自测试设计

内建自测试是一种有效的测试存储器的方法.分析了NOR型flash存储器的故障模型和测试存储器的测试算法,在此基础上,设计了flash存储器的内建自测试控制器.控制器采用了一种23位的指令,并且通过JATG接口来控制,结果通过扫描链输出.验证结果表明,设计的内建自测试结构对固定故障、转换故障、桥接故障、耦合故障、栅极干扰、漏极干扰、过渡擦除和读干扰均有100%的故障覆盖率.     

基于边界扫描技术的复杂电子设备系统级测试研究

以提高复杂电子设备系统级测试能力为目的,在对边界扫描技术进行研究的基础上.论述和总结了基于边界扫描的电子设备系统级测试的硬件结构、测试方案和测试装置,并提出了软件系统的结构设计;同时,按照IEEE1149.5标准的MTM—BUS总线进行了结构设计和功能仿真;实验结果表明,基于边界扫描的系统级测试技术能够广泛应用于现代电子设备,特别是MTM—BUS总线结构具有快速、准确、简单等特点;该研究和设计不仅对复杂电子设备系统级测试技术进行了总结,而且对改善电子设备系统级测试性能具有十分重要的指导意义。     

Syndrome-decoding algorithms for static-diagnosis models

The problem of finding fault patterns consistent with a given syndrome is discussed for graph-theoretical diagnosis models such as the fault-diagnosis and self-diagnosis models. The fault-diagnosis model consists of two types of vertices, fault units and measurements, and is expressed by a bipartite graph. Faulty states of a fault unit always imply abnormal states of all the measurements which are adjacent to the unit, otherwise a measurement remains normal. A self-diagnosis model consists of one type of unit which has the capability of testing other units and being tested itself. The testing relation is represented by a directed arc; this produces test outcomes which are invalid if the testing unit is faulty. The inverse system which yields a fault pattern from a corresponding syndrome for fault-diagnosis models is studied and a syndrome-decoding algorithm is proposed which works for some class of diagnosis models with observation noise. The algorithm uses a similar measure to the syndrome-decoding algorithm of error-correcting codes which use the Hamming distance. Another measure is presented for the self-diagnosis model expressed by a directed graph and this measure is characterized by a ranking method.     

Optimal maintenance policy incorporating system level and unit level for mechanical systems

The study works on a multi-level maintenance policy combining system level and unit level under soft and hard failure modes. The system experiences system-level preventive maintenance (SLPM) when the conditional reliability of entire system exceeds SLPM threshold, and also undergoes a two-level maintenance for each single unit, which is initiated when a single unit exceeds its preventive maintenance (PM) threshold, and the other is performed simultaneously the moment when any unit is going for maintenance. The units experience both periodic inspections and aperiodic inspections provided by failures of hard-type units. To model the practical situations, two types of economic dependence have been taken into account, which are set-up cost dependence and maintenance expertise dependence due to the same technology and tool/equipment can be utilised. The optimisation problem is formulated and solved in a semi-Markov decision process framework. The objective is to find the optimal system-level threshold and unit-level thresholds by minimising the long-run expected average cost per unit time. A formula for the mean residual life is derived for the proposed multi-level maintenance policy. The method is illustrated by a real case study of feed subsystem from a boring machine, and a comparison with other policies demonstrates the effectiveness of our approach.     

Simulating distributed and coordinated conveying systems

We present the design and implementation of a new object-oriented simulation platform for a decentralized material handling system called the Coordinated Conveying System (CCS). CCS is a new approach to conveying entities, i.e., materials and people. It is also a generalized framework in which the connections between structure and behavior can be systematically studied. In this system, a collection of mobile units moves periodically along fixed tracks. Entities are transferred from some input to an output unit by the mobile units; entities can also transfer between mobile units during a space–time event called a rendezvous. This systems framework and model of conveying exposes a rich spectrum of spatio-temporal behaviors that have interesting connections to core issues in scheduling, resource allocation, communication, embedded systems, automation, and programming. The complexity of CCS arises from the interactions between the mobile units; hence, it is difficult to construct a system-level model for these dynamic behaviors, even though the behavior of individual units is simple. For these reasons, the simulator we present enables a systematic investigation of cyber-physical issues in CCS. Since all the details of CCS are not yet fully understood, we designed an extensible simulator using the Model-View-Controller architecture. The object-oriented approach helped us to model the CCS artifacts in a natural manner and, hence, reduced the complexity of our design.     

考虑集成故障与单元互测的系统级测试性分配与设计

随着装备系统复杂度、集成度的不断增加，系统集成故障和单元间互测因素越来越凸显，给系统级测试性分配和设计带来了新问题，主要表现在：传统方法未考虑集成故障和单元互测导致测试性指标分配不合理，系统级测试性设计缺乏系统级测试选择方法等。针对系统集成后产生的集成故障和单元间互测等情形进行了理论分析，提出了考虑集成故障与单元互测的测试性指标分配、面向集成故障的系统级测试选择方法，为系统级测试性设计提供了一套解决方案。     

系统级综合中结合资源分配的调度算法

在系统级综合中,资源的分配通常由设计者指定,或在设计空间搜索的最外层循环中进行枚举探索.提出了一种结合资源分配的启发式调度算法.它根据当前系统划分的结果,在调度过程中寻找合适的所需资源实例的数目,从而确定系统的资源分配以及调度指派方案.应用该调度算法可使设计空间搜索过程简化为划分、调度和评估三个步骤,省去了最外层的资源分配枚举循环,提高了搜索效率.实验结果验证了该算法的可行性和有效性.     

The economics of system-level testing

Competitive pressure to streamline system-level test without affecting product quality is mounting. Identifying the features unique to system-level testing, the authors present key results of production testing based on a new test cost model     

Multimodal person detection system

Person detection is often critical for personal safety, property protection, and national security. Most person detection technologies implement unimodal classification, making predictions based on a single sensor data modality, which is most often vision. There are many ways to defeat unimodal person detectors, and many more reasons to ensure technologies responsible for detecting the presence of a person are accurate and precise. In this paper, we design and implement a multimodal person detection system which can acquire data from multiple sensors and detect persons based on a variety of unimodal classifications and multimodal fusions. We present two methods of generating system-level predictions: (1) device perspectives which makes a final decision based on multiple device-level predictions and (2) system perspectives which combines data samples from multiple devices into a single data sample and then makes a decision. Our experimental results show that system-level predictions from system perspectives are generally more accurate than system-level predictions from device perspectives. We achieve an accuracy of 100%, zero false positive rate and zero false negative rate with fusion of system perspectives motion and distance data.

     

Lightweight coarse-grained coordination: a scalable system-level approach

In this paper, our solution to the problem of modelling functionally complex communication systems at the application level, based on lightweight coordination, is extended to seamlessly capture system-level testing as well. This extension could be realized simply by self-application: the bulk of the work for integrating system-level testing into our development environment, the ABC, concerned domain modelling, which can be done using the ABC. Therefore, the extension of the ABC to cover system-level testing was merely an application development on the basis of the ABC, illustrated here in the domain of Computer Telephony Integration. Here the adoption of a coarse-grained approach to test design, which is central to the scalability of the overall testing environment, is the enabling aspect for system-level test automation. Together with our lightweight coordination approach this induces an understandable modelling paradigm of system-wide test cases that is adequate for the needs and requirements of industrial test engineers. In particular, it enables test engineers to graphically design complex test cases that, in addition, can even be automatically checked for their intended purposes via model checking.     

A fast pessimistic diagnosis algorithm for generalized hypercube multicomputer systems

The reliability of processors is an important issue for designing a massively parallel processing system for which fault-tolerant computing is crucial. In order to achieve high system reliability and availability, a faulty processor (node) when found should be replaced by a fault-free processor. Within a multiprocessor system, the technique of identifying faulty nodes by constructing tests on the nodes and interpreting the test outcomes is known as system-level diagnosis. The topological structure of a multicomputer system can be modeled by a graph of which the vertices and edges correspond to nodes and links of the system, respectively. This work presents a system-level diagnosis algorithm for a generalized hypercube which is an attractive variance of a hypercube. The proposed algorithm is based on the PMC model and can isolate all faulty nodes to within a set which contains at most one fault-free node. If the total number of nodes to be diagnosed in a generalized hypercube is N, the proposed algorithm can run in O(Nlog?N) time, and being superior to Yang??s algorithm proposed in 2004, it can diagnose not only a hypercube but also a generalized hypercube.