网页具有丰富的内容和复杂多变的结构,现有的网页信息提取技术解决了单记录型简单页面的信息提取问题,但是对于多记录型复杂页面的信息提取效果往往不佳。文中提出了一种全新的基于可视块的复杂网页信息自动化提取算法(Visual Block Bas...网页具有丰富的内容和复杂多变的结构,现有的网页信息提取技术解决了单记录型简单页面的信息提取问题,但是对于多记录型复杂页面的信息提取效果往往不佳。文中提出了一种全新的基于可视块的复杂网页信息自动化提取算法(Visual Block Based Information Extraction,VBIE),通过启发式规则构建可视块与可视块树,然后通过区域聚焦、噪声过滤及可视块筛选,实现了对复杂网页中数据记录的提取。该方法摒弃了以往算法对网页结构的特定假设,无需对HTML文档进行任何人工标记,保留了网页的原始结构,且能够在单页面上实现无监督的信息提取。实验结果表明,VBIE的网页信息提取精确度最高可达100%,在主流搜索引擎的结果页面和社区论坛的帖子页面上的F1均值分别为98.5%和96.1%。相比目前方法中在复杂网页上提取效果较好的CMDR方法,VBIE的F1值提高了近16.3%,证明了该方法能够有效解决复杂网页的信息提取问题。展开更多
In this paper, we propose a flexible locationbased service （LBS） middleware framework to make the development and deployment of new location based applications much easier. Considering the World Wide Web as a huge d...In this paper, we propose a flexible locationbased service （LBS） middleware framework to make the development and deployment of new location based applications much easier. Considering the World Wide Web as a huge data source of location relative information, we integrate the common used web data extraction techniques into the middleware framework, exposing a unified web data interface for the upper applications to make them more attractive. Besides, the framework also emphasizes some common LBS issues, including positioning, location modeling, location-dependent query processing, privacy and secure management.展开更多
文摘网页具有丰富的内容和复杂多变的结构,现有的网页信息提取技术解决了单记录型简单页面的信息提取问题,但是对于多记录型复杂页面的信息提取效果往往不佳。文中提出了一种全新的基于可视块的复杂网页信息自动化提取算法(Visual Block Based Information Extraction,VBIE),通过启发式规则构建可视块与可视块树,然后通过区域聚焦、噪声过滤及可视块筛选,实现了对复杂网页中数据记录的提取。该方法摒弃了以往算法对网页结构的特定假设,无需对HTML文档进行任何人工标记,保留了网页的原始结构,且能够在单页面上实现无监督的信息提取。实验结果表明,VBIE的网页信息提取精确度最高可达100%,在主流搜索引擎的结果页面和社区论坛的帖子页面上的F1均值分别为98.5%和96.1%。相比目前方法中在复杂网页上提取效果较好的CMDR方法,VBIE的F1值提高了近16.3%,证明了该方法能够有效解决复杂网页的信息提取问题。
基金Supported by the National Natural Science Foun-dation of China (60573091 ,60273018)National Basic Research andDevelopment Programof China(2003CB317000) +1 种基金the Key Project ofMinistry of Education of China (03044) Programfor NewCentu-ry Excellent Talents in University(NCET) .
文摘In this paper, we propose a flexible locationbased service （LBS） middleware framework to make the development and deployment of new location based applications much easier. Considering the World Wide Web as a huge data source of location relative information, we integrate the common used web data extraction techniques into the middleware framework, exposing a unified web data interface for the upper applications to make them more attractive. Besides, the framework also emphasizes some common LBS issues, including positioning, location modeling, location-dependent query processing, privacy and secure management.
