Test Data Volume Research Articles

Test data decompression for multiple scan designs with boundary scan

The paper presents an efficient scheme to compress and decompress in parallel deterministic test patterns for circuits with multiple scan chains. It employs a boundary-scan-based environment for high quality testing with flexible trade-offs between test data volume and test application time while achieving a complete fault coverage for any fault model for which test cubes are obtainable. It also reduces bandwidth requirements, as all test cube transfers involve compressed data. The test patterns are generated by the reseeding of a two-dimensional hardware structure which is comprised of a linear feedback shift register (LFSR), a network of exclusive-or (XOR) gates used to scramble the bits of test vectors, and extra feedbacks which allow including internal scan flip-flops into the decompressor structure to minimize the area overhead. The test data decompressor operates in two modes: pseudorandom and deterministic. In the first mode, the pseudorandom pattern generator (PRPG) is used purely as a generator of test vectors. In the latter case, variable-length seeds are serially scanned through the boundary-scan interface into the PRPG and parts of internal scan chains and, subsequently, a decompression is performed in parallel by means of the PRPG and selected scan flip-flops interconnected to form the decompression device. Extensive experiments with the largest ISCAS' 89 benchmarks show that the proposed technique greatly reduces the amount of test data in a cost effective manner.

Strength and Ductility of Confined Concrete

An analytical model is proposed to construct a stress‐strain relationship for confined concrete. The model consists of a parabolic ascending branch, followed by a linear descending segment. It is based on calculation of lateral confinement pressure generated by circular and rectilinear reinforcement, and the resulting improvements in strength and ductility of confined concrete. A large volume of test data, including poorly confined and well‐confined concrete was evaluated to establish the parameters of the analytical model. Confined concrete strength and corresponding strain are expressed in terms of equivalent uniform confinement pressure provided by the reinforcement cage. The equivalent uniform pressure is obtained from average lateral pressure computed from sectional and material properties. Confinement by a combination of different types of lateral reinforcement is evaluated through superposition of individual confinement effects. The descending branch is constructed by defining the strain corresponding to 85% of the peak stress. This strain level is expressed in terms of confinement parameters. A constant residual strength is assumed beyond the descending branch, at 20% strength level. The model is compared against a large number of column tests. Circular, square, and rectangular columns, with spiral and rectilinear reinforcements, as well as welded wire fabric, are used for comparison. Comparisons include concentric and eccentric loadings, as well as slow and fast strain rates. The results indicate good agreement.

Bayesian reliability assessment for discrete data—A case study

The ever-increasing reliability requirement and reduced programme schedules and budgets, particularly in the field of space research, make very real the problem of producing reliability assessments without a large volume of objective test data. In this paper, an attempt is made to utilize Bayesian statistics for reliability measurement of a complex system by combining prior information actual test data for each subsystem. Bayesian statistics, as applied herein, codes the information available from past experience into a prior probability distribution which is updated with test results as they became available. The study includes: 1. (i) Bayesian models for discrete data analysis; 2. (ii) application of the Monte Carlo simulation technique for convolving subsystem reliability distributions together in order to arrive at the overall system reliability and 3. (iii) implementation of the Bayesian reliability measurement programme for the evaluation of the reliability estimate of a typical system of the satellite launch vehicle.

Review of built-in test methodologies for gate arrays

The paper presents a review of current and proposed test methodologies for semicustom gate arrays. The necessity of high quality testing is emphasised by considering some of the hazards and penalties associated with poor testability. The usefulness and limitations of testability analysis programs are then considered. A built-in test is introduced as an attractive alternative to conventional approaches based on automatic test pattern generation for highly structured circuits. This test technique is shown to offer significant benefits, including reduced test data volume, improved test quality, and easier maintenance testing. The advantages and disadvantages of three built-in test implementations for gate arrays are discussed. First, an architecture which combines an ad hoc design for testability with a comprehensive on-chip maintenance system is reviewed. This is followed by a presentation of an LSSD-based pseudorandom self-test and the associated test problems. Finally an exhaustive test, based on a similar architecture achieves a high quality test with guaranteed fault coverage. In conclusion, the future direction of test strategy development is predicted, in the context of increasing integration density and the convergence of ‘semicustom’ and ‘full-custom’ design styles.

Review of built-in test methodologies for gate arrays

The paper presents a review of current and proposed test methodologies for semicustom gate arrays. The necessity of high quality testing is emphasised by considering some of the hazards and penalties associated with poor testability. The usefulness and limitations of testability analysis programs are then considered. A built-in test is introduced as an attractive alternative to conventional approaches based on automatic test pattern generation for highly structured circuits. This test technique is shown to offer significant benefits, including reduced test data volume, improved test quality, and easier maintenance testing. The advantages and disadvantages of three built-in test implementations for gate arrays are discussed. First, an architecture which combines an ad hoc design for testability with a comprehensive on-chip maintenance system is reviewed. This is followed by a presentation of an LSSD-based pseudorandom self-test and the associated test problems. Finally an exhaustive test, based on a similar architecture achieves a high quality test with guaranteed fault coverage. In conclusion, the future direction of test strategy development is predicted, in the context of increasing integration density and the convergence of `semicustom? and `full-custom? design styles.

Genetic toxicology studies using saccharomyces cerevisiae

AbstractThe use of the yeast Saccharomyces cerevisiae in genetic toxicology testing is discussed. The biology of this unicellular eukaryote allows the study of genetic effects in haploid and diploid cells, and in mitotic as well as meiotic cultures. It is at present a prime organism for the study of eukaryotic molecular genetics and cell biology. The genetic system has been thoroughly analysed, and many different types of genetic end points can be studied by using genetically well‐defined but simple tests. Induction of point mutation has been investigated in a number of strains, both in forward and selective reverse mutation assays. One of the most frequently studied genetic effects has been the induction of mitotic recombination. This test has shown a good response to many mutagens and carcinogens, and must be considered as a repair test since mitotic recombination is inducible by damage inflicted upon the genetic nuclear material. There are basically two types of mitotic recombination. At the intragenic level, recombination between different mutational alterations within the same gene can conveniently be studied by using selective techniques; it is due principally to the occurrence of non‐reciprocal recombination between the two mutation sites and is now called mitotic gene conversion. Another type of mitotic recombination is the classical type of reciprocal crossing‐over. Even though testing by using mitotic crossing‐over and associated processes (cumulatively called mitotic segregation) has been based on non‐selective techniques, there is a considerable volume of testing data. Tests for chromosomal malsegregation leading to aneuploidy are now available, but the number of agents tested is still small. Various important and critical aspects of using different yeast systems are discussed. Metabolic activation in yeast is provided by endogeneous P450 systems, but exogenous activation of various kinds, including that available in host mediated assays, has successfully been used.

Centralized large-scale clinical testing in a commercial environment

This article will deal with the role of the large medical testing laboratory, and its increasing importance to the medical community. It will illustrate the necessary interrelationship of technological advances in instrumentation, transportation, and communication. The role of the computer with supporting electronic and electrical systems in handling a large volume of clinical test data will be outlined. From a scientific and economic standpoint, it will demonstrate the merits of volume testing in the areas of quality control, speed, and cost per test. Good business practices and the importance of continuing research, continuing education, continuing growth as adjuncts of the large clinical testing laboratory will be noted. It will show the ability of the large medical testing laboratory, with private capitalization, vision and sound management to keep pace with the demands of physicians for test data for patient diagnosis, evaluation and treatment, today and in the future.