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网站简约本体垂直搜索系统的设计与实现 被引量:2
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作者 杨和平 陈瑜 张志强 《计算机工程与应用》 CSCD 北大核心 2017年第19期257-264,共8页
针对单个网站构建本体库垂直搜索引擎的过程中,叙词及其间逻辑关系等收集整理所耗人力成本高,导致该技术框架虽成熟,而大多网站搜索功能仍以字符匹配为主,缺乏分词、查询扩展及结果的相关度排序,很难准确命中相关查询内容等问题,设计并... 针对单个网站构建本体库垂直搜索引擎的过程中,叙词及其间逻辑关系等收集整理所耗人力成本高,导致该技术框架虽成熟,而大多网站搜索功能仍以字符匹配为主,缺乏分词、查询扩展及结果的相关度排序,很难准确命中相关查询内容等问题,设计并开发了一套基于网站简约本体库的垂直搜索系统。该系统以中国气象数据网(http://data.cma.cn)为例,利用protégé根据网站的导航目录,构建了中国气象数据网的本体库,基于Lucene引擎构建技术框架,对本体库中的对象及网页内容分别进行分词,并构建本体对象索引库及网页索引库;前端对查询内容分词后,先在本体对象索引库中进行扩展,利用TF-IDF相关度算法计算扩展结果的相关度并排序,该值作为各扩展本体对象的权值,并将各自的权值动态赋给利用Jena二次语义分析技术扩展的对象,最后将所有带有权值的关键词在网页索引库中查询检索,计算结果相关度并排序。实验结果表明,该系统构建简便,能为用户扩展、推荐相关查询内容,提高了针对网站检索的查准率及查全率。 展开更多
关键词 本体库 垂直搜索引擎 语义扩展 中国气象数据网
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Development of a 50-year daily surface solar radiation dataset over China 被引量:9
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作者 TANG WenJun YANG Kun +1 位作者 QIN Jun MIN Min 《Science China Earth Sciences》 SCIE EI CAS 2013年第9期1555-1565,共11页
Although solar radiation is a crucial parameter in designing solar power devices and studying land surface processes,long-term and densely distributed observations of surface solar radiation are usually not available.... Although solar radiation is a crucial parameter in designing solar power devices and studying land surface processes,long-term and densely distributed observations of surface solar radiation are usually not available.This paper describes the development of a 50-year dataset of daily surface solar radiation at 716 China Meteorological Administration(CMA) stations.First,a physical model,without any local calibration,is applied to estimate the daily radiation at all 716 CMA routine stations.Then,an ANN-based(Artificial Neural Network) model is applied to extend radiation estimates to earlier periods at each of all 96 CMA radiation stations.The ANN-based model is trained with recent reliable radiation data and thus its estimate is more reliable than the physical model.Therefore,the ANN-based model is used to correct the physical model dynamically at a monthly scale.The correction generally improves the accuracy of the radiation dataset estimated by the physical model:the mean bias error(MBE) averaged over all the 96 radiation stations during 1994-2002 is reduced from 0.68 to 0.11 MJ m-2 and the root mean square error(RMSE) from 2.01 to 1.80 MJ m-2.The new radiation dataset shows superior performance over previous estimates by locally calibrated ngstr m-Prescott models.Based on the new radiation dataset,the annual mean daily solar radiation over China is 14.3 MJ m-2.The maximal seasonal mean daily solar radiation occurs in the Tibetan Plateau during summer with a value of 27.1 MJ m-2,whereas the minimal seasonal mean daily solar radiation occurs in the Sichuan Basin during winter with a value of 4.7 MJ m-2. 展开更多
关键词 Development of a 50-year daily surface solar radiation dataset over China
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