个人对个人电子商务(customer to customer,C2C)是目前主流的电子商务模式之一,为解决C2C电子商务网站中特殊的推荐问题,对传统的二维协同过滤方法进行了扩展,提出了能进行卖家和商品组合推荐的三维协同过滤推荐方法,并在此基础上设计了...个人对个人电子商务(customer to customer,C2C)是目前主流的电子商务模式之一,为解决C2C电子商务网站中特殊的推荐问题,对传统的二维协同过滤方法进行了扩展,提出了能进行卖家和商品组合推荐的三维协同过滤推荐方法,并在此基础上设计了C2C电子商务推荐系统,阐述了该系统的基本架构和推荐过程中的关键运算。该系统利用卖家属性计算卖家相似度,并依据销售关系和卖家相似度对评分数据集进行填充,以解决三维评分数据的稀疏问题;采用协同过滤思想,利用历史评分计算买家相似度,获取最近邻并预测未知评分,最终将预测评分最高的卖家和商品组合推荐给目标买家。实验结果表明,该系统具有较好的推荐效果。展开更多
The conservation status of all the amphibians in China is analyzed,and the country is shown to be a global priority for conservation in comparison to many other countries of the world.Three Chinese regions are particu...The conservation status of all the amphibians in China is analyzed,and the country is shown to be a global priority for conservation in comparison to many other countries of the world.Three Chinese regions are particularly rich in amphibian diversity:Hengduan,Nanling,and Wuyi mountains.Sala-manders are more threatened than frogs and toads.Several smaller families show a high propensity to become seriously threatened:Bombinatoridae,Cryptobranchidae,Hynobiidae and Salamandridae.Like other parts of the world,stream-breeding,high-elevation forest amphibians have a much higher likeli-hood of being seriously threatened.Habitat loss,pollution,and over-harvesting are the most serious threats to Chinese amphibians.Over-harvesting is a less pervasive threat than habitat loss,but it is more likely to drive a species into rapid decline.Five conservation challenges are mentioned with recommendations for the highest priority research and conservation actions.展开更多
文摘个人对个人电子商务(customer to customer,C2C)是目前主流的电子商务模式之一,为解决C2C电子商务网站中特殊的推荐问题,对传统的二维协同过滤方法进行了扩展,提出了能进行卖家和商品组合推荐的三维协同过滤推荐方法,并在此基础上设计了C2C电子商务推荐系统,阐述了该系统的基本架构和推荐过程中的关键运算。该系统利用卖家属性计算卖家相似度,并依据销售关系和卖家相似度对评分数据集进行填充,以解决三维评分数据的稀疏问题;采用协同过滤思想,利用历史评分计算买家相似度,获取最近邻并预测未知评分,最终将预测评分最高的卖家和商品组合推荐给目标买家。实验结果表明,该系统具有较好的推荐效果。
文摘The conservation status of all the amphibians in China is analyzed,and the country is shown to be a global priority for conservation in comparison to many other countries of the world.Three Chinese regions are particularly rich in amphibian diversity:Hengduan,Nanling,and Wuyi mountains.Sala-manders are more threatened than frogs and toads.Several smaller families show a high propensity to become seriously threatened:Bombinatoridae,Cryptobranchidae,Hynobiidae and Salamandridae.Like other parts of the world,stream-breeding,high-elevation forest amphibians have a much higher likeli-hood of being seriously threatened.Habitat loss,pollution,and over-harvesting are the most serious threats to Chinese amphibians.Over-harvesting is a less pervasive threat than habitat loss,but it is more likely to drive a species into rapid decline.Five conservation challenges are mentioned with recommendations for the highest priority research and conservation actions.
