2,819 research outputs found

    Path analysis for process troubleshooting

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    Modelling valve stiction

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    A continuous stirred tank heater simulation model with applications

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    This article presents a first principles simulation of a continuous stirred tank heater pilot plant at the University of Alberta. The model has heat and volumetric balances, and a very realistic feature is that instrument, actuator and process non-linearities have been carefully measured, for instance to take account of the volume occupied by heating coils in the tank. Experimental data from step testing and recordings of real disturbances are presented. The model in Simulink and the experimental data are available electronically, and some suggestions are given for their application in education, system identification, fault detection and diagnosis.© Elsevie

    Cache-oblivious index for approximate string matching

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    This paper revisits the problem of indexing a text for approximate string matching. Specifically, given a text T of length n and a positive integer k, we want to construct an index of T such that for any input pattern P, we can find all its k-error matches in T efficiently. This problem is well-studied in the internal-memory setting. Here, we extend some of these recent results to external-memory solutions, which are also cache-oblivious. Our first index occupies O((nlog kn)B) disk pages and finds all k-error matches with O((|P|+occ)B+log knloglog Bn) I/Os, where B denotes the number of words in a disk page. To the best of our knowledge, this index is the first external-memory data structure that does not require Ω (|P|+occ+poly(logn)) I/Os. The second index reduces the space to O((nlogn)B) disk pages, and the I/O complexity is O((|P|+occ)B+log k(k+1)nloglogn) . © 2011 Elsevier B.V. All rights reserved.postprin

    A retrospective review of the long term clinical outcomes of patients with neurogenic lower urinary tract dysfunction following transverse myelitis

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    AIMS: Transverse myelitis (TM) is an inflammation of the spinal cord which causes neurological deficit in motor, sensory, and autonomic pathways. Persistent neurogenic lower urinary tract dysfunction (NLUTD) is common even where motor and sensory impairment is recovered. Long term follow-up is required to ensure optimal bladder management and protection of the upper tracts. We describe the clinical outcomes for a cohort of patients with TM who have received neurourological follow-up in a specialist center. METHODS: A retrospective review of TM patient records was performed. Current pharmaceutical and surgical management, upper tract status, and patient reported symptoms are reported. Changes in urodynamic parameters and bladder emptying technique between current and baseline were analyzed. RESULTS: Sixty patients with NLUTD following TM were identified. The mean age at onset of NLUTD was 29 years (0-77 years). The mean follow-up was 13 years. 55% of patients were taking antimuscarinic medication, 53% of patients had intradetrusor botulinum toxin injections and 5% had bladder augmentation surgery. Forty-one patients had a baseline and recent urodynamic study which could be compared. Fifty-three of fifty-eight patients with a recent renal ultrasound had normal renal appearance. Four had mild hydronephrosis and one more extensive hydronephrosis. CONCLUSION: TM can have a persistent effect on lower urinary tract function. There is potential for upper tract damage if bladder management is not optimized. We have demonstrated that in a specialist neurourology unit within a tertiary center, one can provide acceptable long term outcomes following international guidelines
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