6,307 research outputs found

    Transient upsets in microprocessor controllers

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    The modeling and analysis of transient faults in microprocessor based controllers are discussed. Such controllers typically consist of a microprocessor, read only memory storing and application program, random access memory for data storage, and input/output devices for external communications. The effects of transient faults on the performance of the controller are reviewed. An instruction level perspective of performance is taken which is the basis of a useful high level program state description of the microprocessor controller. A transition matrix is defined which determines the controller's response to transient fault arrivals

    Intermittent/transient faults in digital systems

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    Containment set techniques are applied to 8085 microprocessor controllers so as to transform a typical control system into a slightly modified version, shown to be crashproof: after the departure of the intermittent/transient fault, return to one proper control algorithm is assured, assuming no permanent faults occur

    Intermittent/transient fault phenomena in digital systems

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    An overview of the intermittent/transient (IT) fault study is presented. An interval survivability evaluation of digital systems for IT faults is discussed along with a method for detecting and diagnosing IT faults in digital systems

    Intermittent/transient faults in computer systems: Executive summary

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    An overview of an approach for diagnosing intermittent/transient (I/T) faults is presented. The development of an interrelated theory and experimental methodology to be used in a laboratory situation to measure the capability of a fault tolerant computing system to diagnose I/T faults, is discussed. To the extent that such diagnosing capability is important to reliability in fault tolerant computing systems, this theory and supporting methodology serves as a foundation for validation efforts

    Toward the assessment of the susceptibility of a digital system to lightning upset

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    Accomplishments and directions for further research aimed at developing methods for assessing a candidate design of an avionic computer with respect to susceptability to lightning upset are reported. Emphasis is on fault tolerant computers. Both lightning stress and shielding are covered in a review of the electromagnetic environment. Stress characterization, system characterization, upset detection, and positive and negative design features are considered. A first cut theory of comparing candidate designs is presented including tests of comparative susceptability as well as its analysis and simulation. An approach to lightning induced transient fault effects is included

    Limitations of CD44v6 amplification for the detection of tumour cells in the blood of colorectal cancer patients

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    Based on the important role of CD44 splice variants in colorectal cancer progression and metastasis, we evaluated the use of CD44v6 expression to detect and assess the metastatic potential of colorectal tumour cells circulating in peripheral blood. A nested amplification was designed that allowed to detect 10–100 colon cancer cells. This assay was applied to blood samples from healthy donors. Strong signals were detected in all cases, indicating that it cannot be used to detect colorectal carcinoma cells in whole blood. We then included an enrichment step based on the use of an anti-epithelial cells monoclonal antibody (BerEP4) coupled to magnetic beads. The CD44v6 reverse transcription polymerase chain reaction (RT PCR) assay was performed on cDNA synthesized from blood samples treated with these beads. We analysed 18 samples from 12 patients with a gastrointestinal disease, and 36 samples from ten patients with a colorectal cancer. None of the patients used as negative controls were found to contain epithelial cells in their blood as determined by cytokeratin 19 RT-PCR. By contrast, CD44 transcripts containing exon v6 were detected in nine out of the 18 samples tested (50%). For the colorectal cancer patients, six out of the seven samples (85.7%) that were cytokeratin 19-positive were CD44v6-negative, whereas ten samples out of the 29 not containing epithelial cells were CD44v6-positive (34.5%). This is probably due to the persistence of CD8+ leucocytes in the enriched preparations, as determined by PCR analysis of the CD8 α-chain. We conclude that detection of CD44v6 transcripts using a sensitive nested RT-PCR assay has no potential value to detect and characterize colorectal cancer micrometastases from blood, even following an initial enrichment step. © 2000 Cancer Research Campaig

    Brain, cognition, and language development in spinal muscular atrophy type 1: a scoping review

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    Aim: To summarize the current knowledge on brain involvement in spinal muscular atrophy (SMA) type 1, focusing on brain pathology, cognition, and speech/language development. / Method: A scoping review was performed using the methodology of the Joanna Briggs Institute. Five databases and references from relevant articles were searched up to December 2019. Articles were screened on the basis of titles and abstracts. Full‐text papers published in peer‐reviewed journals in English were selected. / Results: Nineteen articles met eligibility criteria. Eight case series/reports on brain pathology showed abnormalities in few SMA type 0/1 cases, supported by findings in three post‐mortem examinations in mice. Four studies (three case–control, one cross‐sectional) on cognition reported contradictory results, with impaired cognitive performances in recent, small groups with SMA type 1. Four studies (three cross‐sectional, one observational) on speech/language showed that untreated SMA type 1 patients rarely achieve functional and intelligible speech, with data limited to parent reports/non‐formal evaluations. / Interpretation: Brain involvement is an under‐investigated aspect of SMA type 1, requiring further exploration in longitudinal studies. A deeper knowledge of brain involvement would improve the interpretation of clinical phenotypes and the personalization of rehabilitation programmes supporting patients' autonomies and quality of life. Additionally, it may help to define further outcome measures testing the efficacy of current and new developing drugs on this domain

    The dimension of loop-erased random walk in 3D

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    We measure the fractal dimension of loop-erased random walk (LERW) in 3 dimensions, and estimate that it is 1.62400 +- 0.00005. LERW is closely related to the uniform spanning tree and the abelian sandpile model. We simulated LERW on both the cubic and face-centered cubic lattices; the corrections to scaling are slightly smaller for the face-centered cubic lattice.Comment: 4 pages, 4 figures. v2 has more data, minor additional change
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