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Based on the new curriculum reform and big data technology, this paper uses the radial function and RBF neural network algorithm in the multidimensional data analysis method to obtain the center, variance and output layer power of the neurons of Probability Theory and Mathematical Statistics. Construct the teaching evaluation model of Probability Theory and Mathematical Statistics according to the RBF neural network algorithm and screen 25 secondary indicators from the three aspects of teachers, students, and course content, thus forming the teaching evaluation index system of Probability Theory and Mathematical Statistics. Determine the evaluators and evaluation methods, according to the specific implementation of the evaluation. The evaluation model of “Teaching Probability Theory and Mathematical Statistics” based on the RBF neural network is tested for reliability and validity. The results show that the evaluation values of 25 indicators in the indicator system of the RBF-based evaluation model for the teaching of Probability Theory and Mathematical Statistics are all out of the range of 8.010-9.0, and |u1| = 16.392≥2.241, |u2| = 10.052≥2.241 in the examination scores of Probability Theory and Mathematical Statistics from the second semester of the academic year 2018/2019 to the second semester of the academic year 2020/2021, i.e., the examination scores of the course for the five semesters as a whole do not obey a normal distribution. This study enables students to better master the theoretical knowledge of Probability Theory and Mathematical Statistics, which is of great significance to the educational reform and practical exploration of Probability Theory and Mathematical Statistics in colleges and universities.

In the era of widespread digital image sharing on social media platforms, deep-learning-based watermarking has shown great potential in copyright protection. To address the fundamental trade-off between the visual quality of the watermarked image and the robustness of watermark extraction, we explore the role of structural features and propose a novel edge-aware watermarking framework. Our primary innovation lies in the edge-aware secret hiding module (EASHM), which achieves adaptive watermark embedding by aligning watermarks with image structural features. To realize this, the EASHM leverages knowledge distillation from an edge detection teacher and employs a dual-task encoder that simultaneously performs edge detection and watermark embedding through maximal parameter sharing. The framework is further equipped with a social network noise simulator (SNNS) and a secret recovery module (SRM) to enhance robustness against common image noise attacks. Extensive experiments on three public datasets demonstrate that our framework achieves superior watermark imperceptibility, with PSNR and SSIM values exceeding 40.82 dB and 0.9867, respectively, while maintaining an over 99% decoding accuracy under various noise attacks, outperforming existing methods by significant margins. [ABSTRACT FROM AUTHOR]

A double-layer broadband high-transmission terahertz linear-to-circular polarization metasurface is experimentally demonstrated in frequencies between 0.46 and 0.62 THz. The measured results show a good agreement with the simulations. The values of co-polarization transmission coefficients T x x and T y y remain above 0.82 in both simulation and experiment, and the simulated and measured axial ratio is 26.2% and 29.6%, respectively. Moreover, the experimental ellipticity remains above 0.98 in the region from 0.5 to 0.62 THz. The average measured polarization conversion ratio is 0.68. The multi-reflection and transmission interference model is used to explain the physical mechanism of polarization conversion. The proposed structure could be used in terahertz transmission and detection because of its stable, high ellipticity and transmittance. [ABSTRACT FROM AUTHOR]

A wide-angle terahertz metamaterial absorber is designed, fabricated, and measured. The resonant structure on the top layer of the absorber consists of two metal crosses with different sizes. The wider and higher absorption is achieved when compared with the structures that only consist of a large or small cross under different incident angles. Physical mechanisms of the absorption are clarified by their electric field distributions. The influence of the permittivity and the loss tangent of the dielectric on the absorptions are also investigated. The terahertz band sample was developed based on a double-faced copper dielectric plate using the conventional printed circuit board (PCB) technique. This saves time and allows for low cost and large-area fabrication as an alternative to the expensive conventional lithography method. The reflection spectra of the sample at oblique incidence are directly obtained using a vector network analyzer in conjunction with a quasi-optical test bench, which is used instead of the most common Fourier Transform Infrared spectrometry or Terahertz (THz) time-domain spectroscopy method in the terahertz band. The measured results are in good agreement with those of the simulation. The proposed terahertz metamaterial absorber will be crucial in the implementation of future terahertz sensors, THz communication systems, and other emerging THz technologies. [ABSTRACT FROM AUTHOR]

With the growing demand for broadband wireless communication, high-resolution radar, security inspection, and biological analysis, terahertz (THz) technology has made significant progress in recent years. The wide applications of THz technology benefited from the rapid development of various THz functional devices. Metasurface, an essential means of manipulating THz waves, has widely been applied in multiple THz functional devices. However, it is still a great challenge to construct flexible THz metasurface devices due to the lack of flexibility of traditional semiconductor and metal materials. In this work, a two-dimensional material, MXene, is used to prepare flexible metasurfaces with frequency filtering and polarization functions. By further combining with the phase-transition-material vanadium dioxide, the VO2/MXene metasurface exhibits good performance in amplitude modulation under electrical stimulation. The modulation depth of the device reaches 86% under a lower trigger power of 11.6 mW/mm2 and the response time is only ∼100 ms. Such a flexible active metasurface with superior performance and high integration will be useful in THz imaging systems, THz sensing systems, etc. [ABSTRACT FROM AUTHOR]