The analysis method of the Hilbert spectrum entropy of dividing frequency range for signals of heart rate variability / 生物医学工程学杂志

The signal analysis of heart rate variability (HRV) has been very significant for heart disease of aided diagnosis, monitoring and evaluation. We proposed a new method of HRV signal analysis based on the Hilbert spectrum entropy dividing frequency range. According to Hilbert spectrum characteristics of the multi-resolution and the characteristic of HRV signal frequency spectrum, the Hilbert time-frequency spectrum entropy of HRV signal in different frequency range and the full frequency Hilbert time-frequency spectrum entropy with weighting factor were calculated. This approach was analyzed after the appropriate separation for various physiological factors based on the frequency range and it is more conducive to reflect the physiological and the pathological characteristics. Applying the new approach to the actual HRV signal of the MIT-BIH standard database, we obtained the results which showed that this method could effectively differentiate from the sample group for the young, the elder and the patients with atrial fibrillation, and for the sample group for the healthy persons and CHF patients, the performance in statistical analysis was superior to those of the general time-frequency entropy method. The approach could provide an effective analysis method for clinical HRV signal.

Progress in biofixation of CO2 from combustion flue gas by microalgae / 生物工程学报

Global warming caused by the increasing CO2 concentration in atmosphere is a serious problem in the international political, economic, scientific and environmental fields in recent years. Intensive carbon dioxide capture and storage (CCS) technologies have been developed for a feasible system to remove CO2 from industrial exhaust gases especially for combustion flue gas. In these technologies, the biofixation of CO2 by microalgae has the potential to diminish CO2 and produce the biomass. In this review, the current status focusing on biofixation of CO2 from combustion flue gases by microalgae including the selection of microalgal species and effect of flue gas conditions, the development of high efficient photobioreactor and the application of microalgae and its biomass product were reviewed and summarized. Finally, the perspectives of the technology were also discussed.

Study on Classification of Imaginary Hand Movements Based on Band Power and Wavelet Packet Entropy / 中国康复理论与实践

@#Objective To explore the effect of band power and wavelet packet entropy in the recognition of hand imagery.Methods The data gained from brain computer interface competition in 2003 provided by Graz University of Technology.The electroencephalogram(EEG)signals between 8～16 Hz were decomposed by db3 wavelet packet at three levels.The band power(BP)and wavelet packet entropy(WPE)of C3 and C4 were calculated respectively.The BP and WPE were defined as the feature vector.The left and right hand motor imaginary tasks were distinguished.Results The proposed method was applied to the test data set with 140 trails.The satisfactory results were obtained with the highest classification accuracy 87.14%.Conclusion The band power and wavelet packet entropy of EEG changed with time is coincident with event-related desynchronization and event-related synchronization.It can be used to recognize the left and right band motor imaginary tasks.