7,575 research outputs found

    Support vector recurrent neurofuzzy networks in modeling nonlinear systems with correlated noise

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    Good generalization results are obtained from neurofuzzy networks if its structure is suitably chosen. To select the structure of neurofuzzy networks, the authors proposed a construction algorithm that is derived from the Support Vector Regression. However, the modeling errors are assumed to be uncorrelated. In this paper, systems with correlated modeling errors are considered. The correlated noise is modeled separately by a recurrent network. The overall network is referred to as the support vector recurrent neurofuzzy networks. The prediction error method is used to train the networks, where the derivatives are computed by a sensitivity model. The performance of proposed networks is illustrated by an example involving a nonlinear dynamic system corrupted by correlated noise.published_or_final_versio

    Estimating the number of faults: efficiency of removal, recapture, and seeding

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    Various experimental designs for estimating the number of faults in a system are studied including: (1) removal of each fault as it is detected; (2) marking of each fault as it is detected; and (3) introduction of a known number of faults into the system followed by (1) or (2). A unified framework is developed for comparing these designs; it also produces simplified estimators having high efficiency relative to maximum likelihood estimators. The designs are compared in terms of: (1) statistical accuracy; and (2) the number of failures that need to occur to achieve a given accuracy. On the basis of these comparisons, some general recommendations are made on the level of seeding as well as the choice of removal or recapture designs. When the testing effort is sufficient so that roughly two thirds of the faults are detected, the removal-design is preferred over the recapture-design, and there are no gains from seeding. However, this conclusion depends on assigning unit cost to all fault detections, which might not always be reasonable.published_or_final_versio

    Peri-operative administration of rectal diclofenac sodium. The effect on renal function in patients undergoing minor orthopaedic surgery

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    In a randomized, double-blind study, we administered placebo and diclofenac sodium 100 mg suppositories 1 h pre-operatively and on the first post-operative morning to 22 adult patients undergoing minor orthopaedic surgery. A standardized post-operative intravenous fluid regimen was instituted until oral fluids were tolerated. Renal function was assessed pre-operatively, and on the first and second post-operative days by the measurement of urine output, creatinine, urea, sodium, potassium and NAG (N-acetyl-b-D-glucosaminidase) levels and serum creatinine, urea, sodium and potassium concentrations. On the first postoperative day, the diclofenac group demonstrated a reduced urinary sodium excretion. On the second postoperative day, a reduced urinary NAG/creatinine ratio was observed in the diclofenac group when compared to placebo. We conclude that peri-operative administration of diclofenac causes changes in renal function consistent with prostaglandin inhibition on the first post-operative day but had no lasting adverse effects in this group of patients. Our results reinforce the need for caution when administering this drug in the context of pre-existing renal impairment.published_or_final_versio

    Polarised radiative transfer, rotation measure fluctuations and large-scale magnetic fields

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    Faraday rotation measure at radio wavelengths is commonly used to diagnose large-scale magnetic fields. It is argued that the length-scales on which magnetic fields vary in large-scale diffuse astrophysical media can be inferred from correlations in the observed RM. RM is a variable which can be derived from the polarised radiative transfer equations in restrictive conditions. This paper assesses the usage of RMF (rotation measure fluctuation) analyses for magnetic field diagnostics in the framework of polarised radiative transfer. We use models of various magnetic field configurations and electron density distributions to show how density fluctuations could affect the correlation length of the magnetic fields inferred from the conventional RMF analyses. We caution against interpretations of RMF analyses when a characteristic density is ill-defined, e.g. in cases of log-normal distributed and fractal-like density structures. As the spatial correlations are generally not the same in the line-of-sight longitudinal direction and the sky plane direction, one also needs to clarify the context of RMF when inferring from observational data. In complex situations, a covariant polarised radiative transfer calculation is essential to capture all aspects of radiative and transport processes, which would otherwise ambiguate the interpretations of magnetism in galaxy clusters and larger-scale cosmological structures

    Effect of electronic adherence monitoring on adherence and outcomes in chronic conditions: A systematic review and metaanalysis

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    Introduction Electronic adherence monitoring (EAM) is increasingly used to improve adherence. However, there is limited evidence on the effect of EAM in across chronic conditions and on patient acceptability. We aimed to assess the effect of EAM on adherence and clinical outcomes, across all ages and all chronic conditions, and examine acceptability in this systematic review and meta-analysis. Methods A systematic search of Ovid MEDLINE, EMBASE, Social Work Abstracts, PsycINFO, International Pharmaceutical Abstracts and CINAHL databases was performed from database inception to December 31, 2020. Randomised controlled trials (RCTs) that evaluated the effect of EAM on medication adherence as part of an adherence intervention in chronic conditions were included. Study characteristics, differences in adherence and clinical outcomes between intervention and control were extracted from each study. Estimates were pooled using random-effects meta-analysis, and presented as mean differences, standardised mean differences (SMD) or risk ratios depending on the data. Differences by study-level characteristics were estimated using subgroup meta-analysis to identify intervention characteristics associated with improved adherence. Effects on adherence and clinical outcomes which could not be meta-analysed, and patient acceptability, were synthesised narratively. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was followed, and Risk of bias (RoB) assessed using the Cochrane Collaboration's RoB tool for RCTs. The review is registered with PROSPERO CRD42017084231. Findings Our search identified 365 studies, of which 47 studies involving 6194 patients were included. Data from 27 studies (n = 2584) were extracted for the adherence outcome. The intervention group (n = 1267) had significantly better adherence compared to control (n = 1317), (SMD = 0.93, CI:0.69 to 1.17, p<0.0001) with high heterogeneity across studies (I2 = 86%). There was a significant difference in effect according to intervention complexity (p = 0.01); EAM only improved adherence when used with a reminder and/or health provider support. Clinical outcomes were measured in 38/47 (81%) of studies; of these data from 14 studies were included in a meta-analysis of clinical outcomes for HIV, hypertension and asthma. In total, 13/47 (28%) studies assessed acceptability; patient perceptions were mixed. Interpretation Patients receiving an EAM intervention had significantly better adherence than those who did not, but improved adherence did not consistently translate into clinical benefits. Acceptability data were mixed. Further research measuring effects on clinical outcomes and patient acceptability are needed

    Polarized radiative transfer, rotation measure fluctuations, and large-scale magnetic fields

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    Faraday rotation measure (RM) at radio wavelengths is commonly used to diagnose large-scale magnetic fields. It is argued that the length-scales on which magnetic fields vary in large-scale diffuse astrophysical media can be inferred from correlations in the observed RM. RM is a variable which can be derived from the polarized radiative transfer equations in restrictive conditions. This paper assesses the usage of rotation measure fluctuation (RMF) analyses for magnetic field diagnostics in the framework of polarized radiative transfer. We use models of various magnetic field configurations and electron density distributions to show how density fluctuations could affect the correlation length of the magnetic fields inferred from the conventional RMF analyses. We caution against interpretations of RMF analyses when a characteristic density is ill defined, e.g. in cases of lognormal-distributed and fractal-like density structures. As the spatial correlations are generally not the same in the line-of-sight longitudinal direction and the sky plane direction, one also needs to clarify the context of RMF when inferring from observational data. In complex situations, a covariant polarized radiative transfer calculation is essential to capture all aspects of radiative and transport processes, which would otherwise ambiguate the interpretations of magnetism in galaxy clusters and larger scale cosmological structures

    Manipulation of Polyhydroxybutyrate Properties through Blending with Ethyl-Cellulose for a Composite Biomaterial

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    Polyhydroxybutyrate (PHB) is widely used as a biomaterial in medical and tissue-engineering applications, a relatively high crystallinity limits its application. Blending PHB with ethyl-cellulose (EtC) was readily achieved to reduce PHB crystallinity and promote its degradation under physiological conditions without undue influence on biocompatibility. Material strength of composite films remained unchanged at 6.5 ± 0.6 MPa with 40% (w/w) EtC loadings. Phase separation between the two biopolymers was determined with PHB crystallinity decreasing from 63% to 47% for films with the same loading. This reduction in crystallinity supported an increase in the degradation rates of composite films from 0.39 to 0.81% wk−1 for PHB and its composite, respectively. No significant change in morphology and proliferation of olfactory ensheathing cells were observed with the composites despite significant increases in average surface roughness (Ra) of the films from 2.90 to 3.65 Όm for PHB and blends with 80% (w/w) EtC, respectively. Copyright © 2011 Rodman T. H. Chan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    A study on city motor vehicle emission factors by tunnel test

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