Electrotecnia. Fundamentos teóricos y aplicaciones prácticas. Gray Alexander, Wallace. Aguilar – Foto Libros de Segunda Mano – Ciencias, Manuales y Oficios – Física, Química y Matemáticas: wallace. Compra, venta y subastas de Física. Download Citation on ResearchGate | Electrotecnia: fundamentos teóricos y aplicaciones prácticas / por Alexander Gray y G. A. Wallace | Traducción de.

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A high sensitivity is achieved with the proposed automatic detector, but results should be reviewed by an expert to remove false positives. In Table 3 we show the results comparing the channel involvement during the marked events, between the expert and the automatic detector.

The duration of epilepsy in the 15 patients was The grand mal pattern of Gibbs, Gibbs and Lennox. Electrical Circuits 3 Laboratory Credit: A low frequency signal from a small generator may then be lost in the background noise in scalp recordings, but a generator of the same size could produce a fast oscillation that would stand clearly out of the high frequency background.

Raju 2 Professor, Dept. How reliable are chance-corrected measures of agreement? Hippocampal and entorhinal cortex high-frequency oscillations — Hz in human epileptic brain and in kainic acid-treated rats with chronic seizures. Transient grau gamma-band response in EEG as a manifestation of miniature saccades. This difference in the number of active channels explains the higher sensitivity and lower specificity of the automatic detector at the S95 operating point, compared to the S Conclusions A high sensitivity is achieved with the proposed automatic detector, but results should be reviewed by an expert to remove false positives.

This is a common necessity also for intracranial HFO detectors Staba et al. We can also see in the table that the overall subject level false positive rate is 1. Feature values of the events after the detection stage, for the 15 patients set.

Space performance Another point of interest is whether the high frequency activity is detected at the same channels by the automatic detector and the human expert.


These events may have a power increase in a frequency band relative to wallade background, but the amplitude of the signal is still very small compared to other bands, and the event goes unnoticed in the broadband signal 35— Hz. Supplementary Material S1 Click here to view.

The profession of electrical engineering. Allyson Little 3 years ago Views: Methods In order to design our detector, we adopted the following qualitative definition of an FO: High-frequency oscillations mirror disease activity in patients with epilepsy.

Wsllace oscillations during human focal seizures. We describe next the different quantities we adopt to evaluate the performance of the automatic detector.

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Performance curves of the automatic detector. Course level Undergraduate 1. Associated Data Supplementary Materials S1.

This supports the idea that the automatic detector at this operating point is more sensitive than the expert, detecting weaker but probably real FOs note that for the automatic detector operating at S86 the proportion of spikes with simultaneous fast activity for the automatic detector is 0. C Example of false negatives: A comparison of FE analysis techniques A.

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This provides a strong evidence for a relationship between FOs and epilepsy. Magnetoencephalography — theory, instrumentation, and applications to noninvasive studies of the working human brain. The proposed automatic scalp FO detector shows a good performance in the tested group of patients.

Feyzi Meysam Farrokhifar More information. The sensitivity as a function of the positive predicted value is sometimes called precision-recall PR curve Temko et al. Let x raw [ n ] be the sequence of samples corresponding to any channel of the unprocessed EEG, sampled at Hz.

We will denote this operating point as S Voltages are seldom perfectly elcetrotecnia between phases, but when this unbalance More information.

The proportionality constant c should be chosen as low as possible to have a high sensitivity, but if it is too low there will be detections at some frequency band and channel almost anytime, leading to very long and unrepresentative channel and subject level events. Kappa muddles together two sources of disagreement: True positives and false positives of the automatic detector at operating point S Course area Physics 1. The resulting stop-band attenuation is 40 dB, and pass-band ripple 0.


We grray quite confident that the detected events do not correspond to artifacts associated to bandpass filtering of the spikes since they can be seen in the unfiltered EEG signal in the true positive examples shown in Fig.

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In epileptic patients high frequency oscillations were found in intracranial EEG recordings, both with microelectrodes Bragin et al. The total number of events is given below each diagram, as well as the ranking distance RD value for the automatic detector. Frequencies in the ripple band 80— Hz were observed in children suffering from status epilepticus during sleep Kobayashi et al. Society for Industrial and Applied Mathematics; A Example of true positive events illustrating clear events marked by the expert and identified by the detector.

Then, the threshold values are varied to minimize the number of false positive pre-detections with maximum ratio of broadband to narrowband signal amplitude lower than Threshold A and maximum RMS value larger than Threshold B, always for the previously computed number of true positive pre-detections fulfilling the same conditions.

After all events were marked, the EEG was reviewed a second time by the same reviewer for verification. Scalp-recorded high-frequency oscillations in childhood sleep-induced electrical status epilepticus. The feature used for the classification is the maximum value of this ratio among all the individual events that form a subject level detection.

Higher sampling frequency recordings would allow a more accurate evaluation of the number of events as a function of the frequency.