Detection of pseudosinusoidal epileptic seizure segments in the neonatal EEG by cascading a rule-based algorithm with a neural network

This paper presents an approach to detect epileptic seizure segments in the neonatal electroencephalogram (EEG) by characterizing the spectral features of the EEG waveform using a rule-based algorithm cascaded with a neural network. A rule-based algorithm screens out short segments of pseudosinusoidal EEG patterns as epileptic based on features in the power spectrum. The output of the rule-based algorithm is used to train and compare the performance of conventional feedforward neural networks and quantum neural networks. The results indicate that the trained neural networks, cascaded with the rule-based algorithm, improved the performance of the rule-based algorithm acting by itself. The evaluation of the proposed cascaded scheme for the detection of pseudosinusoidal seizure segments reveals its potential as a building block of the automated seizure detection system under development.     

Time reversal for crack identification

A general computational methodology is proposed for identifying cracks in structures. It is based on a time reversal (TR) technique and on the notion of refocusing. In the proposed procedure, a known source generates waves in the structure, and the time-varying response of the structure is measured only at certain points and times. In an industrial application this step is performed experimentally, but in the present study it is emulated numerically. Relying on a computational model of the structure and on the measured signals, a TR solution is obtained for each assumed set of crack parameters. This amounts to evolving the solution backward in time, till the initiation time of the original source. The crack identification is based on seeking, among all crack candidates, the crack which yields the best wave refocusing at the true source location. To test the proposed methodology, a simple rectangular membrane model governed by the 2D time-dependent scalar wave equation is employed. Finite element discretization of the structure and an explicit time-stepping scheme are used. The performance of the method is tested under various conditions and with various amounts of partial information. Its sensitivity to noise and to perturbations in the material properties is also investigated.     

Quantifying motion in video recordings of neonatal seizures by regularized optical flow methods.

This paper presents the development of regularized optical flow computation methods and an evaluation of their performance in the extraction of quantitative motion information from video recordings of neonatal seizures. A general formulation of optical flow computation is presented and a mathematical framework for the development of practical tools for computing optical flow is outlined. In addition, this paper proposes an alternative formulation of the optical flow problem that relies on a discrete approximation of a family of quadratic functionals. These regularized optical flow computation methods are used to extract motion strength signals from video recordings of neonatal seizures.     

Measurement of reproducibility.

"Reproducibility" refers to "the degree to which one can reproduce a subject's entire response pattern from a knowledge of his total score and the order of difficulty of the items." The purpose of this article is to examine some of the available techniques for assessing "reproducibility," to evaluate these techniques, and to indicate the relationships between these techniques and the concept of reliability. 20 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlation Between the Total Morphology of an Epoxy System and Some of its Properties

Due to the ever growing use of epoxy resins for structural applications, more information is required about their structure-properties relationship. Much work was done on this subject by us and by others, but many questions still remain unanswered. Some problems which require more detailed studies are the influence of factors like compositional changes in the resin (ratio of prepolymer-curing agent), postcuring and cooling of the polymerized resin from temperatures above T_g to room temperature, on physical properties of the product.     

Electric field induced switching of the fluorescence of single semiconductor quantum rods

The exceptional fluorescence properties of single CdSe quantum rods (QRs) arising from internal and external electric fields are studied. Reversible external field induced switching of the emission in single QRs is reported for the first time. This effect was correlated with local field induced emission intensity reduction and newly observed darkening mechanism. Bimodal spectral jumps under a zero field were also observed and assigned to charged exciton emission, a phenomenon that was likewise directly controlled through an external field. These phenomena point to the use of single QRs as spectrally tunable charge sensitive fluorophores with polarized emission in fluorescence tagging and optical switching applications.     

Hydrodynamic method for cleaning inner surfaces of pipes

A new method for cleaning inner surfaces of pipes was studied both theoretically and experimentally. The method is based on the phenomenon of a sphere rotating in a pipe (levitation), when the translational movement of the sphere is restricted and the sphere is subjected to fluid flow in the pipe. The high rotation velocity causes a vibration process, which may be exploited for cleaning sediments or rust from the inner surfaces of pipes. A simplified theoretical model for the determination of the relationships among the dimensionless parameters governing the rotation phenomenon was developed. The model was validated with experimental data and found to be appropriate for engineering design of the system. Application of the cleaning method was demonstrated by cleaning the sediments and rust off the inner surface of a one-inch nominal diameter pipe.     

A constitutive description for aluminum-0.1 pct magnesium alloy under hot working conditions

The constitutive behavior of an aluminum 0.1 wt pct Mg alloy deformed in the temperature range of 573 to 823 K at strain rates between 0.001 and 100 s⁻¹ is analyzed on the basis of the concept of the mechanical threshold stress (MTS), , taking into consideration the contributions from the different strengthening mechanisms that could be present in this alloy, , which include one component that arises from the interaction between dislocations and solute atoms, , and another contribution from the interaction between mobile and forest dislocations, . The evolution of is described in terms of a generalized form of an exponential-saturation equation, whereas the characterization of the ratio, s _i ( , T), between the flow stress at any strain rate and temperature, and the two components is carried out by means of the phenomenological model advanced by Kocks and co-workers. It is shown that the experimental values of the flow stress as well as the work-hardening rate can be accurately described following this approach and that the maximum difference between the experimental and calculated values of such a parameter is less than ±4 MPa. The analysis conducted from continuous stress-strain curves determined at constant temperature and strain rate indicates that the relaxation strain in the generalized form of the Sah et al. relationship displays a significant strain rate dependence. The inclusion of such a dependence into the analysis by means of a simple parametric relationship leads to an improvement in the accuracy of the prediction of the model.     

Effective water diffusivity in deep-fat fried restructured potato product

Water diffusivity was determined for a restructured potato product undergoing deep-fat frying. Pre-fried product gel-strength, expressed by its deformability modulus, varied from 37 to 127 kPa and markedly affected the effective diffusion coefficients, ranging from 3.31 to 1.58 × 10⁻⁹ m² s⁻¹, respectively. Pre- and post-fried effective water diffusivity decreased with higher deformability modulus. Frying time reduced the effective water diffusivity only when the initial deformability modulus was higher than 52 and 79 kPa for 1 and 5 min, respectively. Oil uptake criterion was found to increase with the effective water diffusivity for frying durations of 1 and 5 min.