Minimal Test Set Research Articles

A systematic review of cognitive decline in the general elderly population.

The public health impact of cognitive decline and dementia is increasing as the population ages. Studies exploring therapies or risk factors for cognitive impairment require understanding of expected age-related decline. To establish the rate of age-related cognitive decline in the general elderly population. Systematic review of studies of cognitive decline in the general elderly population. Medline, Embase and PsycINFO databases were searched using an adapted version of McMaster's aetiology, causation and harm strategies and the Cochrane Dementia and Cognitive Impairment Group strategy. Grey literature was explored and experts contacted. A second observer was involved at all stages and quality appraisal of included studies was performed. Included studies were representative, community-based, cohort studies of people aged over 60, incorporating individuals with dementia. Identification of 5990 abstracts and retrieval of 163 full texts led to inclusion of 19 papers. Heterogeneity made narrative review the appropriate method of data synthesis. Some degree of cognitive impairment with increasing age was found in all studies, although the extent varied. The prevalence of cognitive impairment and the rate of decline increased with age. Studies were of variable quality. Cognitive decline is almost universal in the general elderly population and increases with age. Improved communication between researchers and between clinicians to identify a core minimum data set of neuropsychological tests that could be used in different populations would support consistent study design and meta-analysis, helping to quantify the true rate of cognitive decline in the elderly and assisting diagnosis in clinical practice.

Correction to "A minimum universal test set for self-test of EXOR-sum-of-products circuits"

Correction to "A minimum universal test set for self-test of EXOR-sum-of-products circuits"

Evaluating the effect of IMF lending to low-income countries

The purpose of this paper is twofold: to apply to a group of low-income borrowers from the IMF, the most commonly used technique for measuring the independent effects on economic developments of IMF support; and to develop a minimum set of diagnostic tests for determining whether necessary conditions for using the methodology exist. The modified control-group methodology is used to measure the effect of IMF support on three key variables — output growth, inflation, and the external debt/service ratio. The sample comprises adjustment programs begun during 1986–1991 supported by the IMF's Enhanced Structural Adjustment Facility (ESAF). The distinguishing feature of the modified control-group approach is the estimation of a policy counterfactual — policies that would have been followed in the absence of IMF support against which to compare actual policies and resulting outcomes. Using this approach for the ESAF, the sample reveals statistically significant beneficial effects of IMF support on output growth and the debt/service ratio but no effects on inflation. Diagnostic tests of these results, rarely if ever reported in the literature, are shown to be critical in interpreting the validity of the results of assessments of adjustment lending. For this sample, at least, the diagnostic tests cast doubt on the reliability of estimates of the effects of IMF-supported programs using panel data in a modified control-group model. The most obvious and manageable modifications to the model do not overcome its basic weaknesses.

A minimal universal test set for self-test of EXOR-Sum-of-Products circuits

A testable EXOR-Sum-of-Products (ESOP) circuit realization and a simple, universal test set which detects all single stuck-at faults in the internal lines and the primary inputs/outputs of the realization are given. Since ESOP is the most general form of AND-EXOR representations, our realization and test set are more versatile than those described by other researchers for the restricted GRM, FPRM, and PPRM forms of AND-EXOR circuits. Our circuit realization requires only two extra inputs for controllability and one extra output for observability. The cardinality of our test set for an n input circuit is (n+6). For Built-in Self-Test (BIST) applications, we show that our test set can be generated internally as easily as a pseudorandom pattern and that it provides 100 percent single stuck-at fault coverage. In addition, our test set requires a much shorter test cycle than a comparable pseudoexhaustive or pseudorandom test set.

Minimal test set for multi-output threshold circuitsimplemented as bubble sorting networks

An n-input sorting network can be used to implement all n-variable symmetric threshold functions. It is shown that a systolic bubble sorting network can be tested for all single stuck-at faults by carrying out only 2 n tests.

Test set compaction algorithms for combinational circuits

This paper presents a new algorithm, essential fault reduction, for generating compact test sets for combinational circuits under the single stuck-at fault model, and a new heuristic for estimating the minimum single stuck-at fault test set size. These algorithms together with the dynamic compaction algorithm are incorporated into an advanced automatic test pattern generation system for combinational circuits, called MinTest. MinTest found better lower bounds and generated smaller test sets than the previously published results for the ISCAS85 and full scan versions of the ISCAS89 benchmark circuits.

Novel test pattern generators for pseudoexhaustive testing

Pseudoexhaustive testing of a combinational circuit involves applying all possible input patterns to all its individual output cones. The testing ensures detection of all detectable multiple stuck-at faults in the circuit and all detectable combinational faults within individual cones. Test pattern generators based on coding theory principles are not tailored to a specific circuit as they do not utilize any structural information. They usually generate test sets that are several orders of magnitude larger than the minimum size pseudoexhaustive test set required for a specific circuit. In this paper, we describe hardware efficient test pattern generators that employ knowledge of the circuit output cone structures for generating minimal test sets. Using our techniques, we have designed generators that generate minimum size test sets for the ISCAS benchmark circuits.

Test set size minimization and fault detection effectiveness: A case study in a space application

An important question in software testing is whether it is reasonable to apply coverage-based criteria as a filter to reduce the size of a test set. An empirical study was conducted using a test set minimization technique to explore the effect of reducing the size of a test set, while keeping block coverage constant, on the fault detection strength of the resulting minimized test set. Two types of test sets were examined. For those with respect to a fixed size, no test case screening was conducted during the generation, whereas for those with respect to a fixed coverage, each subsequent test case had to improve the overall coverage in order to be included. The study reveals that regardless of how a test set is generated, with or without any test case screening, block minimized test sets have a size/effectiveness advantage, in terms of a significant reduction in test set size and with almost the same fault detection effectiveness, over the original non-minimized test sets.

Worst case tolerance analysis and CLP-based multifrequency test generation for analog circuits

We present an algorithm for automatically generating minimal test sets for parametric faults in linear analog circuits. In a previous work we elaborated a multifrequency test generation method (TPG) for such circuit faults. The method was formulated as a series of optimization problems that were solved by sequential quadratic programming (SQP) available in MATLAB. Such a standard optimization method processes local information and, consequently, cannot guarantee that the found solution is global. This may lead to a poor test selection. Furthermore, the method is semiautomatic and depends on various parameters that must be selected by an experienced user. In this paper, we propose a method based on constraint logic programming (CLP) using relational interval arithmetic (RIA) to solve these optimization problems as a series of constraint satisfaction problems (CSPs). The method is fully automatic and provides tight and guaranteed bounds on the true range of a multivariable nonlinear function. The correctness of the bounds stems from the enumeration of subdivisions of the function and its variable domains while discarding those subdivisions containing no solution. The tightness (i.e., the closeness to the true range) of the bounds can be refined to any desired degree by increasing the fineness of subdivisions imposed on the variable domains and the stringency of the termination criterion at the cost of an increased CPU time. The TPG method was implemented in CLP (BNR) prolog. The effectiveness of our approach is illustrated on a number of nonlinear functions known to be difficult, and two realistic electronic circuits in the context of TPG. Our algorithm accelerated the computation of the various parameters related to the test of a biquadratic filter by a factor ranging from 11 to 29 as compared to the Monte Carlo method.

Minimal C-testable tests for block-CLA adders

This paper examines the testing of Carry Look-Ahead (CLA) adders and blockCLA adders with inter-block carry-ripple. By analysing the testing and fault-effect propagation of each stage of the adder, the paper derives minimal test sets for simple CLAs. The generality of these allows them to be assembled to produce minimal ‘C-testable’ test sets for block-CLA adders. The special cases of unequal block sizes and of no carry-in are also covered. The paper also examines the differing test requirements of the two different forms of CLA adders, the exclusive-OR form and the inclusive-OR form.

3 Pre-operative screening for elective surgery

The primary goal of pre-operative evaluation is to assess adequately the patient's preoperative condition and to diagnose and possibly to treat disturbances and diseases which may be of relevance to the course of anaesthesia, surgery and the post-operative period. A pertinent medical history and a physical examination by an experienced anaesthetist are compulsory. A minimal set of tests should be carried out in all patients. The results obtained from these tests were very abnormal in a variety of studies; the information was not always apparent from the history and the examination although it was of relevance to anaesthesia and the post-operative period. Further laboratory tests such as haematocrit and blood glucose and potassium (K + ) concentrations should only be ordered if indicated on the basis of the history and the examination. This small set of tests seems to be justified for the following reasons: • to identify unexpected risk factors not apparent from the history and the examination; • to avoid additional costs resulting from deferring a case due to incomplete tests; • to avoid medicolegal consequences of a possibly incomplete pre-operative evaluation; • to protect patients from unnecessary invasive investigations.

An efficient test generation for multiple fault coverage of two-rail checkers

The design and implementation of an efficient test generation method for multiple fault coverage of self-testing two-rail checkers are presented. This method involves two steps. In the first step, the minimum set of tests required to detect all multiple faults is determined by working backwards from output to input. In the second step, a novel analytic scheme is used to analyse the test set, to enable the user to simplify the implementation of the test generation procedure. The resultant test has a test length significantly shorter than those previously reported. The test generation method is also suitable for parity checkers.

A CAT Tool for Frequency-domain Testing and Diagnosis on Analog

This paper presents a sensitivity-based test generation tool for analog multifrequency testing and diagnosis. The test generation procedure is based on sensitivity analysis and on fault simulation. This tool generates minimal test sets that maximize the coverage of soft, large and hard component faults and that enhance the coverage of interconnect shorts. An introduction to the problem of analog fault diagnosis considering both component and interconnect faults, is also presented. This procedure is now being automated by integrating commercially available tools for symbolic computation and electrical simulation

A uniform approach to mixed-signal circuit test

Owing to the analogue nature of many industrial processes and the increasing use of microprocessor techniques, many circuits nowadays carry mixed (digital and analogue) signals. As complexities of these circuits increase, the testability of mixed-signal circuits has become an important issue that must be dealt with by both design and test engineers. A systematic approach to study the testability of mixed-signal circuits is urgently needed, because current ad hoc methods cannot efficiently handle increasingly complex and ever-changing circuits. In this paper we develop a uniform and systematic approach to the mixed-signal circuit testability problem. The approach is based on a recently developed theory of discrete event systems. It is suitable for the following tasks: (i) checking the testability of a circuits; (ii) computing the minimum test set; (iii) finding the fault coverage; (iv) dividing a circuit into testable modules.

VLSI Testing for High Reliability: Mixing IDDQ Testing With Logic Testing

In this paper, we examine the effectiveness of combined logic and IDDQ testing to detect stuck-at and bridging faults. The stuck-at faults are detected by the logic test and IDDQ testing detects bridging faults.Near minimal stuck-at test sets are used for this combined logic and IDQQ test environment. These near minimal stuck-at test sets are generated using standard test programs, while using collapsed fault lists. We examined ISCAS '85 and ISCAS '89 benchmark circuits under this combined test environment. A comparison is given for the fault coverage obtained under this combined test environment with other studies based on pure logic test and IDDQ test. Also, the results of IDDQ based test sets (vectors generated specifically for IDDQ testing) are compared with that of stuck-at test sets. Finally, we present a case study on a microprogrammed processor using a functional test set to detect bridging faults in IDDQ testing.

Testing from semi-independent communicating finite state machines with a slow environment

Some systems may be modelled as a set of communicating finite state machines with a slow environment. These machines communicate through the exchange of values. While it is possible to convert such a model into one finite state machine, from which test cases can be derived, this process may lead to an explosion in the number of states. Alternatively it is possible to utilise any independence that exists. The problem of producing a minimal test set, in the presence of certain types of independence and unique input/output sequences, can be represented as a variant of the vehicle routing problem. Possible heuristics for solving this problem are outlined and the method is applied to an example.

Acquisition of language models based on HMnet

Word n-grams and ergodic HMMs were generally used as statistic language models obtained from a large amount of training samples. These models can express short distance correlations between words, however, it is difficult for them to express the long distance correlations between words. In order to solve this problem, a construction algorithm is proposed for a statistic language model based on the hidden Markov network (HMnet). HMnet can express long distance correlations between words. To show the effectiveness of HMnet, it is compared with n-grams and ergodic HMMs by simple experiments. Training and test samples were randomly generated by a stochastic finite state automaton. HMnet showed lower perplexities than word n-grams and ergodic HMMs at an optimum number of states. However, an algorithm is needed for calculating the optimum number of states. If the test set perplexity is estimated from training samples, the optimum number of states is determined as the number with the minimum test set perplexity. So an estimation algorithm of the test set perplexity from training samples has been proposed. From the experimental results, the estimated values were nearly the same values as those for the test set perplexities.

Fault-based ATPG for linear analog circuits with minimal size multifrequency test sets

An automatic test pattern generation (ATPG) procedure for linear analog circuits is presented in this work. A fault-based multifrequency test approach is considered. The procedure selects a minimal set of test measures and generates the minimal set of frequency tests which guarantee maximum fault coverage and, if required, maximal fault diagnosis, of circuit AC hard/soft faults. The procedure is most suitable for linear time-invariant circuits which present significant frequency-dependent fault effects. For test generation, the approach is applicable once parametric tests have determined DC behaviour. The advantage of this procedure with respect to previous works is that it guarantees a minimal size test set. For fault diagnosis, a fault dictionary containing a signature of the effects of each fault in the frequency domain is used. Fault location and fault identification can be achieved without the need of analog test points, and just in-circuit checkers with an observable go/no-go digital output are required for diagnosis. The procedure is exemplified for the case of an analog biquadratic filter. Three different self-test approaches for this circuit are considered. For each self-test strategy, a set of several test measures is possible. The procedure selects, in each case, the minimal set of test measures and the minimal set of frequency tests which guarantee maximum fault coverage and maximal diagnosis. With this, the self-test approaches are compared in terms of the fault coverage and the fault diagnosability achieved.

A Geometric Buchberger Algorithm for Integer Programming

Let IP{A, c} denote the family of integer programs of the form Min cx: Ax = b, x ∈ Nn obtained by varying the right-hand side vector b but keeping A and c fixed. A test set for IPA, c is a set of vectors in Zn such that for each nonoptimal solution α to a program in this family, there is at least one element g in this set such that α − g has an improved cost value as compared to α. We describe a unique minimal test set for this family called the reduced Gröbner basis of IP{A, c}. An algorithm for its construction is presented which we call a geometric Buchberger algorithm for integer programming and we show how an integer program may be solved using this test set. The reduced Gröbner basis is then compared with some other known test sets from the literature. We also indicate an easy procedure to construct test sets with respect to all cost functions for a matrix A ∈ Z(n−2)×n of full row rank.

Cost-effective generation of minimal test sets for stuck-at faults in combinational logic circuits

This paper presents new cost-effective heuristics for the generation of minimal test sets. Both dynamic techniques, which are introduced into the test generation process, and a static technique, which is applied to already generated test sets, are used. The dynamic compaction techniques maximize the number of faults that a new test vector detects out of the yet-undetected faults as well as out of the already-detected ones. Thus, they reduce the number of tests and allow tests generated earlier in the test generation process to be dropped. The static compaction technique replaces N test vectors by M<N test vectors, without loss of fault coverage. During test generation, we also find a lower bound on test set size. Experimental results demonstrate the effectiveness of the proposed techniques.