基于神经网络的认知无线电合作频谱感知     

薛建伟  唐亮  卜智勇 《中国科学院大学学报》2020,37(3):379-386

认知无线电是一种可用于有效缓解当前频谱资源紧张的技术，而频谱感知是认知无线电的前提。针对低信噪比情况下频谱感知性能差的问题，提出一种将信号高阶统计量、协方差矩阵特征值与神经网络相结合的合作频谱感知算法。该算法考虑到认知用户与授权用户的信道衰落情况，利用神经网络较强的多分类能力，将最大-最小特征值之比、平均-最小特征值之比以及高阶统计量作为特征参数，通过神经网络实现合作频谱感知。仿真结果表明，该算法不仅在低信噪比情况下较其他算法具有更高的频谱检测率，而且对频谱中信号的调制类型也有较高的识别率。  相似文献   

Committee standards battles in the era of convergence: Implications for smart systems     

《International Journal of Information Management》2021

By now, there have been many standards battles fought within the same industry or by multiple industries in the market-based standardization. In these battles, incompatible standards compete to win market dominance. While there is some research on standards battles found within a single committee, competitions in the committee-based standardization between standards from different committees or SDOs are underexplored. This paper categorizes the types of standards battles by the mode of standardization and the heterogeneity of actors. A new type referred to as ‘committee standards battles for converging systems’ is introduced and the dynamics of such battles is explored with two cases. The battle between the electric vehicle charging and the smart meter communication standard and the battle between two different vehicle-to-everything (V2X) communication standards are analyzed. The failure in achieving compatibility between different committee standards on the same frequency bands results in communication interference that adversely affects the operation of smart systems. Social incompatibilities between actors and alliances from a mix of industries with vested interests towards a particular standard complicate the battling scene. The findings provide implications in terms of heterogeneity, actors, and government role in standards battles.  相似文献   

Young people with high‐functioning autism and Asperger's syndrome planning for and anticipating the move to college: what supports a positive transition?     

Wendy Mitchell  Bryony Beresford 《British Journal of Special Education》2014,41(2):151-171

For many young people in England, the move into continuing education involves a transfer from the school where they were educated to a further education college. For those with high‐functioning autism or Asperger's syndrome, this can be a challenging process. Past research has demonstrated some of the problems that these young people can encounter. This article by Wendy Mitchell and Bryony Beresford, both based in the Social Policy Research Unit at the University of York, adds to the evidence base by describing how best to support these young people, focusing specifically on ‘young person endorsed’ practice. Data are gleaned from qualitative interviews with 18 young people with high‐functioning autism/Asperger's syndrome. Findings reveal that young people welcomed the involvement of practitioners; however, specific forms of help and knowledge were particularly valued. In addition, it was parents, as opposed to professionals, who typically emerged as the most significant and valued source of support. Implications for practice are discussed, including the support needs of parents.  相似文献   

一类宽平稳量子随机过程及实例分析     

张伦传 《滨州学院学报》2005,21(3):5-7

定义了"宽平稳量子随机过程"的概念,获得了其谱分解定理.辅以统计物理学中的实例为基础.  相似文献   

浅谈扩频通信在无线局域网中的应用     

韩辉珍 《南平师专学报》2007,26(2):56-59

本文阐述扩频通信的工作原理及目前无线局域网的特点和主要传输方式,并就扩频通信的四种工作方式、扩频技术的特点和扩频技术在无线局域网中的应用前景等作了介绍  相似文献   

新兴“X活族”词语及其语用修辞价值     

刘红妮 《毕节师范高等专科学校学报》2008,(6):17-20

“X活族”新词是指“快活族”、“慢活族”、“乐活族”这样新出现的带“活族”的词语。“X活族”新词的句法和语义构成比较复杂;语用上具有继承性与创新性、二次创新和非常规性、音译兼意译,洋为中用的特点;修辞上巧用对比、转喻和概念整合手段,具有形象创新、词约义丰、直指本质以及陌生化的功能。“X活族”新词的涌现,是语言和社会共同作用的结果。  相似文献   

含反射的共轴光具组成像的矩阵方法     

吕佳力 《成都教育学院学报》2008,22(5):62-65

文章介绍了在近轴光线和近轴物条件下,利用对光线跟踪的矩阵方法成像的方法,并说明它在含反射的共轴系统中的应用。  相似文献   

嵌入式手持设备平台设计     

洪艳伟  赖娟  唐益 《乐山师范学院学报》2008,23(5):47-49

本文结合S3C2410X的功能和结构特点,文章基于三星S3C2410X的ARM处理器设计一个可扩展嵌入式手持设备终端平台。文中主要对外围接口电路进行了优化设计,以PCMCIA、液晶触摸屏为例详细说明了接口电路的设计过程。随后分析了针对于手持设备的系统引导部分、操作系统以及图形用户界面系统的软件特点。  相似文献   

电子技术民生应用之红外线报警装置     

周佐琳 《九江职业技术学院学报》2008,(2):25-26

本文研究红外线报警装置在民生应用中的工作原理和使用方法。  相似文献   

紫外线对黑曲霉生长及某些生理活性的影响     

施翠娥  童贯和 《淮南师范学院学报》2008,10(5):13-15

以不同时间的紫外线照射处理后培养观察黑曲霉的生长情况、孢子形态、胞内蛋白质含量以及酶的活性变化。结果表明：紫外线照射后各处理组在长势,孢子形态,胞内蛋白质含量和酶活性方面都发生了不同程度的变化,其中10min处理组的菌株长势更好,孢子更大,胞内蛋白质含量更高,酶活性更强。  相似文献