Automatic modulation recognition of radiation source signals based on two-dimensional data matrix and improved residual neural network

Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this paper.First,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing process.Second,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR model.Finally,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation type.Theoretical analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR method.The recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR.

On-Line Measurement of Ion Density in Atmospheric Nitrogen Discharge Filaments via Radiation Signals from Plasma Oscillation

Diagnosis of the particle number density of plasma plays an important role in the understanding of plasma sources and processing.Regular radiation signals from plasma oscillation in filaments of atmospheric nitrogen discharge,which were excited by the injection of secondary electron beams during the propagation of the streamer,are employed to determine the ion density of plasma and its evolution in the filaments.Results show that the density of N4＋ in a filament of atmospheric nitrogen discharge is of the order of 1013 cm-3.It is also found that the recombination processes play a dominant role in plasma decay,and that the ion density decreases non-monotonically with time during streamer propagation.

SIGNAL TRANSDUCTION IN LYMPHOCYTES AFTER LOW DOSE RADIATION

Mice were given whole-body irradiation (WBI) with 75 mGy X-rays which had previously been found to stimulate immunologic functions. This low dose radiation (LDR) potentiated |Ca2+|i mobilization in thymic and splenic lymphocytes in response to Con A and anti-CD3 McAb and activated protein kinase C in T and B lymphocytes of the spleen. The expression of TCR / CD3 molecules on the thymocytes was en-chanced after LDR indicating an expedited maturation and differentiation process in the thymus. The changes in TCR / CD3 expression and |Ca2-|i mobilization in response to McAb-CD3 after LDR was found to be highly correlated. Meanwhile the transcription of c-fos and c-jun genes was up-regulated beginning 3 hours after LDR. The expression of IL2R in actived thymocytes was potentiated 24 hours after LDR which coincided with the previous finding of increased secretion of IL2 by splenocytes after WBI with 75 mGy X-rays. It is first reported in the present paper that LDR could stimulate immunologic functions through facilitation of the signal transduction process in the lymphocytes.