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Region Pair Grey Difference Classifier for Face Detection 被引量:1
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作者 欧凡 刘冲 欧宗瑛 《Transactions of Tianjin University》 EI CAS 2010年第2期118-122,共5页
A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition betwee... A new kind of region pair grey difference classifier was proposed. The regions in pairs associated to form a feature were not necessarily directly-connected, but were selected dedicatedly to the grey transition between regions coinciding with the face pattern structure. Fifteen brighter and darker region pairs were chosen to form the region pair grey difference features with high discriminant capabilities. Instead of using both false acceptance rate and false rejection rate, the mutual information was used as a unified metric for evaluating the classifying performance. The parameters of specified positions, areas and grey difference bias for each single region pair feature were selected by an optimization processing aiming at maximizing the mutual information between the region pair feature and classifying distribution, respectively. An additional region-based feature depicting the correlation between global region grey intensity patterns was also proposed. Compared with the result of Viola-like approach using over 2 000 features, the proposed approach can achieve similar error rates with only 16 features and 1/6 implementation time on controlled illumination images. 展开更多
关键词 face detection region pair grey feature region grey pattern correlation machine learning
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国际油价对天然气溢价影响的研究——以日本为例 被引量:1
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作者 杨鑫磊 董秀成 +1 位作者 蒋庆哲 刘贵贤 《价格理论与实践》 CSSCI 北大核心 2018年第6期66-69,共4页
长期以来,与北美和欧洲区域相比亚太地区的天然气进口价格存在较高的溢价。天然气区域间价差较大程度上受国际油价影响,天然气主要通过天然气定价方式和能源产品替代两个方面影响天然气区域价差,形成亚洲天然气溢价。本文采用向量自回... 长期以来,与北美和欧洲区域相比亚太地区的天然气进口价格存在较高的溢价。天然气区域间价差较大程度上受国际油价影响,天然气主要通过天然气定价方式和能源产品替代两个方面影响天然气区域价差,形成亚洲天然气溢价。本文采用向量自回归模型(VAR),选取2007-2015年的月度数据,分析油价与日本-德国天然气区域(JGRS)价差、日本-美国天然气区域(JARS)价差的互相作用关系。建议在油价处于较高价位或是稳定回升时期,考虑加强与美国天然气贸易;建立天然气交易中心,提高谈判议价能力;密切中日韩合作关系。 展开更多
关键词 天然气溢价 区域价差 国际油价
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