超透镜是超表面在成像领域中具有较大应用潜力的平面光学器件,能够精确调控光的相位、振幅、偏振等信息、兼容互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)制造工艺,在器件轻量化和批量化制造等方面具有很大的...超透镜是超表面在成像领域中具有较大应用潜力的平面光学器件,能够精确调控光的相位、振幅、偏振等信息、兼容互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)制造工艺,在器件轻量化和批量化制造等方面具有很大的发展前景。针对近红外成像镜头的轻量化需求,使用时域有限差分(finite-difference time-domain,FDTD)软件设计仿真了工作波长为800 nm的硅基偏振不敏感超透镜,镜头厚度小于0.5 mm,数值孔径为0.41时聚集效率为75%。针对FDTD软件仿真时间较长、硬件要求较高、平面波边缘消散等问题,提出了三维和远场计算相结合的仿真方法;利用波印廷矢量和电场强度积分两种方法分别对超透镜聚集效率进行了计算。对比实验表明:三维和远程计算相结合的方法仿真时间降低了70%,计算机内存需求降低了50%。展开更多
在当今数字化时代,开源技术、开源软件和开源社区日益重要,而通过量化分析方法研究开源领域的问题也已经成为一个重要的趋势。开发者是开源项目中的核心,其贡献度的量化以及量化后的贡献度提升策略,是开源项目能够健康发展的关键。文中...在当今数字化时代,开源技术、开源软件和开源社区日益重要,而通过量化分析方法研究开源领域的问题也已经成为一个重要的趋势。开发者是开源项目中的核心,其贡献度的量化以及量化后的贡献度提升策略,是开源项目能够健康发展的关键。文中提出了一种数据驱动的开源贡献度量化评估与持续优化方法,并通过一个实际的工具框架Rosstor(Robotic Open Source Software Mentor)进行了实现。该框架包含两个主要部分:1)贡献度评估模型,采取了熵权法,可以动态客观地评估开发者的贡献度;2)贡献度持续优化模型,采取了深度强化学习方法,最大化了开发者的贡献度。文中选取了GitHub上若干著名的开源项目的贡献者数据,通过大量且充分的实验验证了Rosstor不仅能够使所有项目上开发者的贡献度得到大幅度提升,而且还具有一定的抗干扰性,充分证明了所提方法和框架的有效性。Rosstor框架为当下广泛开展的开源项目和开源社区的可持续健康发展提供了方法和工具方面的支持。展开更多
With the arrival of the big data era,the phenomenon of information overload is becoming increasingly severe.In response to the common issue of sparse user rating matrices in recommendation systems,a collaborative filt...With the arrival of the big data era,the phenomenon of information overload is becoming increasingly severe.In response to the common issue of sparse user rating matrices in recommendation systems,a collaborative filtering recommendation algorithm was proposed based on improved user profiles in this study.Firstly,a profile labeling system was constructed based on user characteristics.This study proposed that user profile labels should be created using basic user information and basic item information,in order to construct multidimensional user profiles.TF-IDF algorithm was used to determine the weights of user-item feature labels.Secondly,user similarity was calculated by weighting both profile-based collaborative filtering and user-based collaborative filtering algorithms,and the final user similarity was obtained by harmonizing these weights.Finally,personalized recommendations were generated using Top-N method.Validation with the MovieLens-1M dataset revealed that this algorithm enhances both recommendation Precision and Recall compared to single-method approaches(recommendation algorithm based on user portrait and user-based collaborative filtering algorithm).展开更多
文摘在当今数字化时代,开源技术、开源软件和开源社区日益重要,而通过量化分析方法研究开源领域的问题也已经成为一个重要的趋势。开发者是开源项目中的核心,其贡献度的量化以及量化后的贡献度提升策略,是开源项目能够健康发展的关键。文中提出了一种数据驱动的开源贡献度量化评估与持续优化方法,并通过一个实际的工具框架Rosstor(Robotic Open Source Software Mentor)进行了实现。该框架包含两个主要部分:1)贡献度评估模型,采取了熵权法,可以动态客观地评估开发者的贡献度;2)贡献度持续优化模型,采取了深度强化学习方法,最大化了开发者的贡献度。文中选取了GitHub上若干著名的开源项目的贡献者数据,通过大量且充分的实验验证了Rosstor不仅能够使所有项目上开发者的贡献度得到大幅度提升,而且还具有一定的抗干扰性,充分证明了所提方法和框架的有效性。Rosstor框架为当下广泛开展的开源项目和开源社区的可持续健康发展提供了方法和工具方面的支持。
文摘With the arrival of the big data era,the phenomenon of information overload is becoming increasingly severe.In response to the common issue of sparse user rating matrices in recommendation systems,a collaborative filtering recommendation algorithm was proposed based on improved user profiles in this study.Firstly,a profile labeling system was constructed based on user characteristics.This study proposed that user profile labels should be created using basic user information and basic item information,in order to construct multidimensional user profiles.TF-IDF algorithm was used to determine the weights of user-item feature labels.Secondly,user similarity was calculated by weighting both profile-based collaborative filtering and user-based collaborative filtering algorithms,and the final user similarity was obtained by harmonizing these weights.Finally,personalized recommendations were generated using Top-N method.Validation with the MovieLens-1M dataset revealed that this algorithm enhances both recommendation Precision and Recall compared to single-method approaches(recommendation algorithm based on user portrait and user-based collaborative filtering algorithm).
