Anilesh Dey

Fractal analysis of EEG signals for studying the effect of cognitive stress on brain

This work aims to study the development of stress in different section of brain under various mental stress conditions, while the brain performs variety of cognitive tasks. The cognitive tasks are designed so as to cover a wide range of brain activities, which includes puzzle solving, decision making, mathematical calculation, memorisation and recollection, correlation and matching. The purpose is to see whether different level of stresses could be developed under varied conditions. In this article we use Multifractal Detrended Fluctuation Analysis (MFDFA) to observe the different changes in different lobes of the brain. It is found that there is an effect on frontal and parietal lobes during the cognitive task. In order to confirm the results of MFDFA analysis, we also obtain topological scalp map. The features of topological scalp map are found to support the results of MFDFA.

Does Music Affect HRV Impulse? A Time Domain Study

The two-dimensional (2D) Poincare plot of HRV signal reflects the effect of different external stimuli on ANS. The classification is generally done by fitting an ‘ellipse’ on the dense region of the constructed Poincare plot of HRV signal. However, 2D Poincare plot sometimes fails to describe the proper behaviour of the system. One such example is 2D Poincare plot of HRV signal in pre-music and on-music condition. In fact, 2D Poincare plots in pre and on-music condition look almost similar for few subjects. So a proper classification tool is sought for. In this article, an improved technique called ‘3D Poincare plot with proper delay’ has been applied to properly distinguish the pre-music and on-music state of some normal healthy subjects.

Analysis of Similarity Between Protein Sequences Through the Study of Symbolic Dynamics

Protein sequence analysis is an important tool to decode the logic of life. The rapid growth of protein sequences is constantly throwing several challenges to the bioscientists. So several methods are being improvised to assign mathematical descriptors to protein sequences, in order to quantitatively compare the sequences and determine similarities and dissimilarities between them. In this paper, for the analysis of protein sequences their 4-bit ranks and entropies are studied and compared with each other which yields satisfactorily convenient results.

Effect of Audio Cue on Electrooculogram-Based Eye Movement Analysis of Visual Memory Recall

Context aware ubiquitous computing systems are capable of assisting people by sensing human cognitive context. In this work, visual memory recall of human beings is identified by analysing their eye movements. Electrooculogram signals, potential difference produced in the surrounding region of eye socket for eye ball movement, are recorded to collect eye movement data. Electrooculogram signals while viewing ‘repeated’ and ‘non-repeated’ visual stimuli were classified for ‘with’ and ‘without’ audio cue sections. Adaptive autoregressive parameters, power spectral density, Hjorth parameters and wavelet coefficients are extracted from these signals as features. A combined feature space is formed comprising all four signal features. A maximum accuracy of 88.70 % is obtained on an average over five participating subjects using SVM-RBF classifier for ‘without audio’ visual memory recall. From this study, it is evident that this auditory effect leaves an impact on EOG signal patterns so that to make reduction in the recognition performance.