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Plamen Tzvetanov Rossen Todoroff Rousseff Zdravka Radionova 《Journal of Zhejiang University. Science. B》2009,10(1):52-56
Objective: To investigate the masseter inhibitory reflex (MIR) and its eventual changes in patients with episodic tension-type headache (TTH). Methods: MIR was studied in 21 patients with episodic TTH and 30 healthy subjects, with age and sex matched to the study cohort. Median age of patients was 17,0 years (ranged 16～49 years), median duration of disease 12 months (1～5 years), and median frequency of headache 7.5 d per month. Results: The second period of suppression (S2) of MIR was reduced in intensity and duration in 10% of controls and 66.7% (confidence interval (CI)=45.3%～85%; P<0.05) of patients with episodic TTH (χ2=74.9; P<0.001). In 3 (14.3%) of patients with episodic TTH, S2 was completely absent. No significant correlation between the duration of disease and headache frequency was found. Conclusion: Our results confirm the link between episodic TTH and reduction or absence of S2. Teenage patients with episodic TTH may exhibit marked pathological changes in S2 in contrast to older individuals. 相似文献
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In this paper, quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed. The following factors are considered: (a) boundary digging forces allowed for by the stability of an excavator, (b) boundary digging forces enabled by the driving mechanisms of the excavator, (c) factors taking into consideration the digging position in the working range of an excavator, and (d) sign and direction of potential digging resistive force. A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising: an undercarriage, a rotational platform and an attachment with boom, stick, and bucket. On the basis of the mathematical model of the excavator, software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator. By using the developed software, the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass (around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms. The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models. 相似文献
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Jonas Richiardi Andrzej Drygajlo Plamen Prodanov 《Journal of The Franklin Institute》2006,343(6):574-595
Speaker verification is a biometric identity verification technique whose performance can be severely degraded by the presence of noise. Using a coherent notation, we reformulate and review several methods which have been proposed to quantify the uncertainty in verification results, some with a view to coping with the effects of mismatched training-testing environments. We also include a recently proposed method, which is firmly rooted in a probabilistic approach and interpretation, and explicitly measures signal quality before assigning a reliability value to the speaker verification classifier's decision. We evaluate the performance of the confidence and reliability measures over a noisy 251-users database, showing that taking into account signal-domain quality can lead to better accuracy in prediction of classifier errors. We discuss possible strategies for using the measures in a speaker verification system, balancing acquisition duration and verification error rate. 相似文献
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Agnes Stancel-Piątak Plamen Mirazchiyski Deana Desa 《European Journal of Education》2013,48(4):498-510
This article gives a short overview based on the EU High Level Group of Experts on Literacy (HLWG) report to address issues and challenges in Europe on improving literacy competencies in schools. Furthermore, an analysis is conducted focusing on the promotion of reading and early literacy skills in schools taking into account psychological and institutional learning conditions in three countries (Denmark, Germany, and France) with different outcomes in PIRLS 2011 (Progress in International Reading Literacy Study). Country comparison is conducted using multiple groups – multilevel structural equation modelling (MG-MSEM). An important finding is that policy action taken in order to evaluate and improve school effectiveness in each country must address particular needs of its educational system. Suggestions for improving reading achievement in schools are derived from the analysis. 相似文献
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