Packet clock recovery using a bismuth oxide fiber-based optical power limiter

Abstract: We demonstrate an optical clock recovery circuit that extracts the line rate component on a per packet basis from short data packets at 40 Gb/s. The circuit comprises a Fabry-Perot filter followed by a novel power limiting configuration, which in turn consists of a 5m highly nonlinear bismuth oxide fiber in cascade with an optical bandpass filter. Both experimental and simulation-based results are in close agreement and reveal that the proposed circuit acquires the timing information within only a small number of bits, yielding a packet clock for every respective data packet. Moreover, we investigate theoretically the scaling laws for the parameters of the circuit for operation beyond 40 Gb/s and present simulation results showing successful packet clock extraction for 160 Gb/s data packets. Finally, the circuit's potential for operation at 320 Gb/s is discussed, indicating that ultrafast packet clock recovery should be in principle feasible by exploiting the passive structure of the device and the fsec-scale nonlinear response of the optical fiber

Inter-hemispheric EEG coherence analysis in Parkinson's disease : Assessing brain activity during emotion processing

Parkinson’s disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3–AF4, F7–F8, F3–F4, FC5–FC6, T7–T8, P7–P8, and O1–O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities

Revealing Real-Time Emotional Responses: a Personalized Assessment based on Heartbeat Dynamics

Emotion recognition through computational modeling and analysis of physiological signals has been widely investigated in the last decade. Most of the proposed emotion recognition systems require relatively long-time series of multivariate records and do not provide accurate real-time characterizations using short-time series. To overcome these limitations, we propose a novel personalized probabilistic framework able to characterize the emotional state of a subject through the analysis of heartbeat dynamics exclusively. The study includes thirty subjects presented with a set of standardized images gathered from the international affective picture system, alternating levels of arousal and valence. Due to the intrinsic nonlinearity and nonstationarity of the RR interval series, a specific point-process model was devised for instantaneous identification considering autoregressive nonlinearities up to the third-order according to the Wiener-Volterra representation, thus tracking very fast stimulus-response changes. Features from the instantaneous spectrum and bispectrum, as well as the dominant Lyapunov exponent, were extracted and considered as input features to a support vector machine for classification. Results, estimating emotions each 10 seconds, achieve an overall accuracy in recognizing four emotional states based on the circumplex model of affect of 79.29%, with 79.15% on the valence axis, and 83.55% on the arousal axis

The Effect of Lateralization of Motor Onset and Emotional Recognition in PD Patients Using EEG

The objective of this research was to investigate the relationship between emotion recognition and lateralization of motor onset in Parkinson’s disease (PD) patients using electroencephalogram (EEG) signals. The subject pool consisted of twenty PD patients [ten with predominantly leftsided (LPD) and ten with predominantly rightsided (RPD) motor symptoms] and 20 healthy controls (HC) that were matched for age and gender. Multimodal stimuli were used to evoke simple emotions, such as happiness, sadness, fear, anger, surprise, and disgust. Artifactfree emotion EEG signals were processed using the auto regressive spectral method and then subjected to repeated ANOVA measures. No group differences were observed across behavioral measures? however, a significant reduction in EEG spectral power was observed at alpha, beta and gamma frequency oscillations in LPD, compared to RPD and HC participants, suggesting that LPD patients (inferred righthemisphere pathology) are impaired compared to RPD patients in emotional processing. We also found that PD related emotional processing deficits may be selective to the perception of negative emotions. Previous findings have suggested a hemispheric effect on emotion processing that could be related to emotional response impairment in a subgroup of PD patients. This study may help in clinical practice to uncover potential neurophysiologic abnormalities of emotional changes with respect to PD patient’s motor onset

"SEE and SEE": An educational tool for hard of hearing children

An educational software, namely "SEE and SEE", that aims to enhance literacy skills of deaf or hard of hearing children is presented in this paper. The proposed computer-based educational environment, takes into account children's visual learning characteristics. The software provides a series of adjustable functionalities to the teacher, so s/he can create visual-kinetic educational information for each pupil. Moreover, pupils have the opportunity to use bilateral presentations of the information content, by evoking sign language video for each text sentence, accompanied with comprehensive diagrams and pictures. A series of test-questions are also incorporated that reflect the contribution of each educational process to the learning curve. The whole activity is logged and archived at a local database that outputs statistic/activity reports and files. "SEE and SEE" can prove to be a useful learning object that contributes to the normalization of the educational environment towards the children needs

"SEE and SEE": An educational tool for kids with hard of hearing

An educational software, namely "SEE and SEE", that aims to enhance literacy skills of deaf or hard of hearing children is presented in this paper. The proposed computer-based educational environment, takes into account children's visual learning characteristics. The software provides a series of adjustable functionalities to the teacher, so s/he can create visual-kinetic educational information for each pupil. Moreover, pupils have the opportunity to use bilateral presentations of the information content, by evoking sign language video for each text sentence, accompanied with comprehensive diagrams and pictures. A series of testquestions are also incorporated that reflect the contribution of each educational process to the learning curve. The whole activity is logged and archived at a local database that outputs statistic/activity reports and files. "SEE and SEE" can prove to be a useful learning object that contributes to the normalization of the educational environment towards the children needs. © 2008 IEEE