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151.
介绍BP神经网络的结构及相关算法,并通过实验比较不同情况下对BP神经网络的收敛速度与分类精度的影响。实验表明,合适的参数设置能提高BP神经网络算法的分类精度。 相似文献
152.
153.
通过神经网络和模糊控制技术的结合,实现了模糊神经网络控制器FNNC和神经网络预测器NNP的结构设计。该设计可以提高压缩机的控制精度,加强控制系统的适应性,实现压缩机的智能化。 相似文献
154.
为了解决煤矿井下温度控制的应用需求,提出了一种采用分布式的煤矿井下温度调节算法.该算法通过分布在矿井下不同位置的温度传感器探测矿井下的温度,采用模糊神经网络的策略对井下的温度进行调节和控制.给出模糊神经网络的隶属度函数以及模糊函数,仿真测试表明,所设计的温度控制算法具有较强的鲁棒性. 相似文献
155.
基于BP神经网络算法在分类预测方面的权威性,提出利用BP神经网络构建教师履职评价模型的新方法。实验结果表明,该模型具有较高的可行性和实用性,能够准确、高效地对教师履职情况进行客观评价。 相似文献
156.
聂立申 《江西师范大学学报(哲学社会科学版)》2015,(3)
金代泰山及周边地区文化昌达,涌现出大量文人学士。这些文士依籍贯和活动区域不同可大致划分为本地型、周边型和活动型三大类。通过诗酒酬唱、畅游山林、臧否人物等方式,泰山文士构筑了广泛的社会交往网络;与女真贵族、外地文士、道教人士的交往拓展了泰山文士社交网络的空间。泰山文士交游网络的构建与拓展不仅有利于北方各地区的民族融合与社会信息交流对于传承并发展泰山文化亦有重要作用。 相似文献
157.
Ronan Van Rossem Marjolijn Vermande Beate Völker Chris Baerveldt 《British Journal of Sociology of Education》2015,36(5):669-688
Social capital is generally considered beneficial for students’ school adjustment. This paper argues that social relationships among pupils generate social capital at both the individual and the class levels, and that each has its unique effect on pupils’ performance and well-being. The sample in this study consists of 1036 children in 60 first-grade classes in 46 Dutch elementary schools. Multilevel regression results show that a substantial proportion of the variance in school adjustment can be attributed to the class level and that both individual-level and classroom-level social capital have substantial effects on school adjustment. At the individual level, the size of one’s network is more important than its structure. At the collective level, social capital also has a ‘dark side’ because it can have negative effects on adjustment, lowering the academic performance in a class. 相似文献
158.
Eeva Pyörälä Laura Hirsto Auli Toom Liisa Myyry Sari Lindblom-Ylänne 《International Journal for Academic Development》2015,20(2):150-162
The University of Helsinki established a Teachers’ Academy to reward excellence in teaching. This study focuses on teachers’ significant networks and their meaningful conversations about teaching and learning before the establishment of the Teachers’ Academy. The research data consisted of answers to open-ended questions, and were examined using social network analysis. The teachers’ network consisted of significant relations with (1) colleagues and other teachers, (2) peers in pedagogical courses and pedagogical experts, (3) students, and (4) family members and friends. The conversations with different parties varied in nature, content and the level of confidentiality. 相似文献
159.
Ke Li Yingfeng Li Xinyu Wang Mengkui Cui Bolin An Jiahua Pu Jintao Liu Boyang Zhang Guijun Ma Chao Zhong 《国家科学评论(英文版)》2021,8(8)
Marine diatoms construct their hierarchically ordered, three-dimensional (3D) external structures called frustules through precise biomineralization processes. Recapitulating the remarkable architectures and functions of diatom frustules in artificial materials is a major challenge that has important technological implications for hierarchically ordered composites. Here, we report the construction of highly ordered, mineralized composites based on fabrication of complex self-supporting porous structures—made of genetically engineered amyloid fusion proteins and the natural polysaccharide chitin—and performing in situ multiscale protein-mediated mineralization with diverse inorganic materials, including SiO2, TiO2 and Ga2O3. Subsequently, using sugar cubes as templates, we demonstrate that 3D fabricated porous structures can become colonized by engineered bacteria and can be functionalized with highly photoreactive minerals, thereby enabling co-localization of the photocatalytic units with a bacteria-based hydrogenase reaction for a successful semi-solid artificial photosynthesis system for hydrogen evolution. Our study thus highlights the power of coupling genetically engineered proteins and polysaccharides with biofabrication techniques to generate hierarchically organized mineralized porous structures inspired by nature. 相似文献
160.
Liuqing Yang Ce Zhang Xiwen Yu Yingfang Yao Zhaosheng Li Congping Wu Wei Yao Zhigang Zou 《国家科学评论(英文版)》2021,8(8)
Aerospace milestones in human history, including returning to the moon and manned Martian missions, have been implemented in recent years. Space exploration has become one of the global common goals, and to ensure the survival and development of human beings in the extraterrestrial extreme environment has been becoming the basic ability and technology of manned space exploration. For the purpose of fulfilling the goal of extraterrestrial survival, researchers in Nanjing University and the China Academy of Space Technology proposed extraterrestrial artificial photosynthesis (EAP) technology. By simulating the natural photosynthesis of green plants on the Earth, EAP converts CO2/H2O into fuel and O2 in an in-situ, accelerated and controllable manner by using waste CO2 in the confined space of spacecraft, or abundant CO2 resources in extraterrestrial celestial environments, e.g. Mars. Thus, the material loading of manned spacecraft can be greatly reduced to support affordable and sustainable deep space exploration. In this paper, EAP technology is compared with existing methods of converting CO2/H2O into fuel and O2 in the aerospace field, especially the Sabatier method and Bosch reduction method. The research progress of possible EAP materials for in-situ utilization of extraterrestrial resources are also discussed in depth. Finally, this review lists the challenges that the EAP process may encounter, which need to be focused on for future implementation and application. We expect to deepen the understanding of artificial photosynthetic materials and technologies, and aim to strongly support the development of manned spaceflight. 相似文献