By applying phase-only technique in array antenna pattern synthesis, antenna arrays can form desired patterns with the use of phase shifters only. A novel phase-only pattern synthesis algorithm is proposed for the pas...By applying phase-only technique in array antenna pattern synthesis, antenna arrays can form desired patterns with the use of phase shifters only. A novel phase-only pattern synthesis algorithm is proposed for the passive phased array seeker. This algorithm synthesizes the main beam of the antenna pattern through least-squares approximation, thus minimizing the errors between the actual and the desired main beams. The synthesis problem can be solved by applying gradient-descent optimization. The item for suppressing side lobes is added to the above synthesis problem. To obtain a side lobe level as low as possible, the algorithm assigns different weights to different directions in the side lobe region. The algorithm is run repeatedly and the weights are adjusted adaptively according to the normalized power in the side lobe directions. Detailed examples are presented to demonstrate the accuracy and effectiveness of the proposed approach.展开更多
Metasurfaces have revolutionized planar optics due to their prominent ability in light field manipulation.Recently,the incorporation of machine learning has further improved computational efficiency and reduced the re...Metasurfaces have revolutionized planar optics due to their prominent ability in light field manipulation.Recently,the incorporation of machine learning has further improved computational efficiency and reduced the reliance on professionals in designing various metasurfaces.However,the prevalent methods still suffer from configuration complexity and expensive training costs due to more than one model or a combination of rule-driven algorithms.This study proposes a deep learningbased paradigm using only one deep learning model for the end-to-end design of versatile metasurfaces.The adopted deepenhanced RseNet acts both as the surrogate of the electromagnetic simulator in forward spectrum prediction and as the path for backward gradient descent optimization of the meta-atom structures in the paralleled calculation.Without loss of generality,a polarization-multiplexing holographic and a polarization-independent vortex metasurface were designed by this paradigm and successfully demonstrated in the terahertz range.The extremely simplified framework presented here will not only propel the design and application of metasurfaces in terahertz communication and imaging fields,but its universality will also accelerate the research and development of subwavelength planar optics across various wavelengths through artificial intelligence[AI]-enhanced design for optical devices.展开更多
为了保障网络环境的安全性,提出了基于集成式图卷积神经网络算法的网络入侵检测技术。研究方法采用随机梯度下降算法和均方根传播(Root Mean Square Propagation,RMSProp)优化器提升了检测模型的训练效率,强化了检测模型的分类效果。研...为了保障网络环境的安全性,提出了基于集成式图卷积神经网络算法的网络入侵检测技术。研究方法采用随机梯度下降算法和均方根传播(Root Mean Square Propagation,RMSProp)优化器提升了检测模型的训练效率,强化了检测模型的分类效果。研究结果显示,研究模型的入侵检测准确率为96.41%~97.18%。可见经过研究模型优化后,入侵检测技术在模型训练效率和模型训练精度上都有明显提升。研究模型可以根据访问来源进行数据分类,提升了入侵检测模型对访问行为的分类效果。同时,分类效果的提升优化了计算机对攻击行为的识别效率,使计算机的防御效果增强,有效保障了用户的网络安全环境。因此,研究为网络入侵行为的检测提供了一个识别效果较好的技术方法。展开更多
基金supported by the National Natural Science Foundation of China(1127301761471196)
文摘By applying phase-only technique in array antenna pattern synthesis, antenna arrays can form desired patterns with the use of phase shifters only. A novel phase-only pattern synthesis algorithm is proposed for the passive phased array seeker. This algorithm synthesizes the main beam of the antenna pattern through least-squares approximation, thus minimizing the errors between the actual and the desired main beams. The synthesis problem can be solved by applying gradient-descent optimization. The item for suppressing side lobes is added to the above synthesis problem. To obtain a side lobe level as low as possible, the algorithm assigns different weights to different directions in the side lobe region. The algorithm is run repeatedly and the weights are adjusted adaptively according to the normalized power in the side lobe directions. Detailed examples are presented to demonstrate the accuracy and effectiveness of the proposed approach.
基金supported by the National Natural Science Foundation of China(Nos.62027820,61975143,62375203,62175180,and 61735012)。
文摘Metasurfaces have revolutionized planar optics due to their prominent ability in light field manipulation.Recently,the incorporation of machine learning has further improved computational efficiency and reduced the reliance on professionals in designing various metasurfaces.However,the prevalent methods still suffer from configuration complexity and expensive training costs due to more than one model or a combination of rule-driven algorithms.This study proposes a deep learningbased paradigm using only one deep learning model for the end-to-end design of versatile metasurfaces.The adopted deepenhanced RseNet acts both as the surrogate of the electromagnetic simulator in forward spectrum prediction and as the path for backward gradient descent optimization of the meta-atom structures in the paralleled calculation.Without loss of generality,a polarization-multiplexing holographic and a polarization-independent vortex metasurface were designed by this paradigm and successfully demonstrated in the terahertz range.The extremely simplified framework presented here will not only propel the design and application of metasurfaces in terahertz communication and imaging fields,but its universality will also accelerate the research and development of subwavelength planar optics across various wavelengths through artificial intelligence[AI]-enhanced design for optical devices.
文摘为了保障网络环境的安全性,提出了基于集成式图卷积神经网络算法的网络入侵检测技术。研究方法采用随机梯度下降算法和均方根传播(Root Mean Square Propagation,RMSProp)优化器提升了检测模型的训练效率,强化了检测模型的分类效果。研究结果显示,研究模型的入侵检测准确率为96.41%~97.18%。可见经过研究模型优化后,入侵检测技术在模型训练效率和模型训练精度上都有明显提升。研究模型可以根据访问来源进行数据分类,提升了入侵检测模型对访问行为的分类效果。同时,分类效果的提升优化了计算机对攻击行为的识别效率,使计算机的防御效果增强,有效保障了用户的网络安全环境。因此,研究为网络入侵行为的检测提供了一个识别效果较好的技术方法。
