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基于部分响应和SCMA的联合检测与译码算法
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作者 刘梦 刘威 周志刚 《中国科学院大学学报(中英文)》 CSCD 北大核心 2020年第5期657-662,共6页
稀疏码分多址(SCMA)是一种新型非正交多址技术,具有过载通信的特点。在高信噪比(Eb/N0)场景下基于消息传递(MPA)的译码算法,误比特率性能不理想。因此,提出一种部分响应与稀疏码分多址联合调制译码模型,方案继承了SCMA在译码端的低复杂... 稀疏码分多址(SCMA)是一种新型非正交多址技术,具有过载通信的特点。在高信噪比(Eb/N0)场景下基于消息传递(MPA)的译码算法,误比特率性能不理想。因此,提出一种部分响应与稀疏码分多址联合调制译码模型,方案继承了SCMA在译码端的低复杂性和部分响应的高容错性。为进一步降低联合译码的误比特率,将部分响应的Viterbi译码级联至MPA迭代译码过程中,即每次迭代过程中变量节点都会进行一次Viterbi译码,从而组成新型联合译码模块。仿真结果表明,改进后联合编译码模型能够有效降低系统对E b/N 0的需求,同时保持较低的误比特率。 展开更多
关键词 稀疏码分多址 消息传递算法 部分响应 联合调制解调
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Joint detection method of pornographic images with skin-like color background
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作者 唐朝伟 Leng Zhenfeng +2 位作者 Shao Yanqing Tang Hui Zhou Xu 《High Technology Letters》 EI CAS 2012年第2期132-138,共7页
A novel approach is proposed to automatically detect pomographic images with skin-like color background on the Intemet using the locations of human faces and bodies. It has two separate skin-color detection steps: th... A novel approach is proposed to automatically detect pomographic images with skin-like color background on the Intemet using the locations of human faces and bodies. It has two separate skin-color detection steps: the first one is to quickly detect the potential human skin-color regions; and the second one is to use an off-the-shelf face detector to locate a human face and then apply hypothesis testing based on series of assumptions which take into account the face-height ratio, body orientation and modem photograph composition common sense, etc. After that, a template matching method is used to further discriminate normal images or pornographic ones. Experimental results show that the proposed method has high precision and real time speed. 展开更多
关键词 face detection pornographic image skin-like color background skin-color detection template matching
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