Dual-band polarimetric HRRP recognition via a brain-inspired multi-channel fusion feature extraction network

Radar high-resolution range profile (HRRP) provides geometric and structural information of target, which is important for radar automatic target recognition (RATR). However, due to the limited information dimension of HRRP, achieving accurate target recognition is challenging in applications. In recent years, with the rapid development of radar components and signal processing technology, the acquisition and use of target multi-frequency and polarization scattering information has become a significant way to improve target recognition performance. Meanwhile, deep learning inspired by the human brain has shown great promise in pattern recognition applications. In this paper, a Multi-channel Fusion Feature Extraction Network (MFFE-Net) inspired by the human brain is proposed for dual-band polarimetric HRRP, aiming at addressing the challenges faced in HRRP target recognition. In the proposed network, inspired by the human brain’s multi-dimensional information interaction, the similarity and difference features of dual-frequency HRRP are first extracted to realize the interactive fusion of frequency features. Then, inspired by the human brain’s selective attention mechanism, the interactive weights are obtained for multi-polarization features and multi-scale representation, enabling feature aggregation and multi-scale fusion. Finally, inspired by the human brain’s hierarchical learning mechanism, the layer-by-layer feature extraction and fusion with residual connections are designed to enhance the separability of features. Experiments on simulated and measured datasets verify the accurate recognition capability of MFFE-Net, and ablative studies are conducted to confirm the effectiveness of components of network for recognition

Experimental and Numerical Investigation of Micro/Mini Channel Flow-Boiling Heat Transfer with Non-Uniform Circumferential Heat Fluxes at Different Rotational Orientations

Flow-boiling of Perfluorohexane (FC-72) in horizontal micro/mini channels was investigated experimen- tally and numerically at different rotational orientations in terms of gravity. One-sided uniform channel heating was considered experimentally for rotational angles ranging from 0 °(heating from below) to 180 °(heating from above) in increments of 30 °. The micro/mini channel had a high aspect ratio of 10 (5 mm x 0.5 mm) and a hydraulic diameter of 909 μm. In-channel flow visualisations were recorded and heat transfer coefficients were determined for mass fluxes of 10, 20 and 40 kg/m 2 s at a saturation temperature of 56 °C. Suitable heat fluxes were applied to span the onset of nucleate boiling to near dry-out conditions within the channel. It was found that the rotational angle had a significant influence on the heat transfer performance due to its influence on bubble detachment. Bottom-heated cases (0 °orientation) resulted in local heat transfer coefficients that were up to 201% higher than for any other rotational orientation. Channel orientations of 60 °(slanted heating surface) and 90 °(heating from the side) generally produced the lowest local heat transfer coefficients. Insight into the influence of the grav- itational orientation on single-bubble growth within the nucleation and detachment region was obtained via two- and three-dimensional numerical simulations. Bubble behaviour after detachment and its effect on heat transfer were also investigated transiently until detachment. The numerical simulations mirrored the experimental trends and it was found that the presence of growing bubbles interrupted the velocity streamlines and the thermal boundary layer downstream of the nucleation sit

Parental Absence Accompanies Worse Academic Achievements: Evidence Based upon a Sample of Left-Behind Children in Rural China

In China, with the rapid urbanization and large amount of labor force migrating from rural-to-urban areas, an enormous number of children living in rural China are in the absence of parental care. The objective of the study was to investigate the academic performance of left-behind children under various statuses of parental absence. We investigated 3,076 children (1,761 non-left-behind and 1,315 left-behind) regarding their academic achievement in different subjects. We found that children with different status of parental absence would perform differently on Chinese, mathematics, and English learning. In addition, left-behind children would be significantly more likely to get low scores in academic examinations as compared with non-left-behind children. Strengths and limitations of the study are discussed

Parental absence predicts suicide ideation through emotional disorders

<div><p>The objectives of the study were to investigate the association between the parental absence and suicide ideation and to examine the roles of emotional disorders in the aforementioned relationship. Four thousand five hundred and thirteen children from rural areas in Jiangsu Province, China, participated in the study. Among the participants, 2416 were non-left-behind children (children living with both parents) and 1997 were left-behind children (children living with the absence of at least one parent). All participants responded to the Center for Epidemiological Studies Depression Scale for Children, the Multidimensional Anxiety Scale for Children, and a question regarding respondents’ suicide ideation. Results indicated that as compared with non-left-behind children, the left-behind children with both-parents absence were statistically more likely to show suicide ideation. Furthermore, all the three types parental absence—father absence, mother absence, and both-parents absence were significantly associated with negative emotional outcomes. Moreover, depression, social anxiety, and physical anxiety were shown to be significant mediators in the relationship of parental absence and suicide ideation of children. The stress of parental absence and its negative impact on children’s mental health are discussed.</p></div

The prevalence of suicide ideation across children with various status of parental absence.

<p>The prevalence of suicide ideation across children with various status of parental absence.</p

Mediating effects of emotional factors in the relationships of parental-absence status to suicide ideation.

<p>Mediating effects of emotional factors in the relationships of parental-absence status to suicide ideation.</p