1 引言 World Wide Web是目前全球最大的信息系统,在WWW上查询Web文档主要依赖于Internet上的索引信息系统,如Yahoo、Infoseek、AltaVista、WebCrawler、Excite、Lycos等等。由于WWW太大又没有良好的结构且Web服务器的自治性,所以Web文...1 引言 World Wide Web是目前全球最大的信息系统,在WWW上查询Web文档主要依赖于Internet上的索引信息系统,如Yahoo、Infoseek、AltaVista、WebCrawler、Excite、Lycos等等。由于WWW太大又没有良好的结构且Web服务器的自治性,所以Web文档的查询难以做到全面而精确。衡量Web文档查询的质量主要有两个方面:①是否能把所有相关的文档资源找出来,不要有所遗漏。展开更多
科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜...科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜索(Improved Bald Eagle Search,IBES)算法优化双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)的组合水质等级预测模型。首先,采用CRITIC法确定各水质指标的权重,加权求和获得一项综合水质指标,从而提出一种改进的水质评价指标体系,以为BiLSTM提供更丰富、更可靠的水质特征信息。其次,在训练过程中引入Logistic映射和莱维飞行策略,并设计交叉共享及准反向搜索策略优化秃鹰搜索(Bald Eagle Search,BES)算法,以提升其种群多样性,增强寻优能力。最后,通过IBES算法迭代寻找BiLSTM的最佳学习率、隐藏层节点数以及正则化系数的超参数组合,进一步提高其预测水平。结果显示:与IBES-BiLSTM、BES-BiLSTM、GA-BiLSTM、PSO-BiLSTM和BiLSTM等模型相比,CRITIC-IBES-BiLSTM模型进行水质等级预测的准确率、精准率、召回率及F_(1)均最高,且具有更好的稳定性。展开更多
With the explosive increase of the network information,people can find information more and more difficultly. The occurrence of the Web search engine overcomes this problem in some degree. This paper tells about the h...With the explosive increase of the network information,people can find information more and more difficultly. The occurrence of the Web search engine overcomes this problem in some degree. This paper tells about the history of the search engine ,the current state of the search engine. Some guidelines about the search engine are analysed and the related checking methods are also given. In this basis, we introduce the trend of the search engine.展开更多
With the explosive increase of the network information,it is more and more difficult for people to look up information. The occurrence of the Web search engines overcomes this problem in some degree. However, because ...With the explosive increase of the network information,it is more and more difficult for people to look up information. The occurrence of the Web search engines overcomes this problem in some degree. However, because different search engines use different mechanisms, scope and algorithms, the repetition of the search results for the same query is no more than 34 %. If wish to get relativly fullscale ,accurate search results,multi-search engines should be used and the meta search engines occur. In this paper ,the meta search engines are surveyed. At first ,the history ,the principles and the elements of the meta search engines are discussed. Then,the related creteria of the meta search engines are analyzed and several typical meta search engines are compared. Finally,on this base,the trend of the meta search engine is introduced.展开更多
介绍了一个高效的元搜索引擎系统SMS(Smart Meta Searchcr),采用检索实例知识库对用户的检索意图进行推理,同时给出一套独特的星级排行评价策略,通过用户行为分析技术为用户提供个性化信息检索服务,以及其在未来搜索引擎个性化、智能化...介绍了一个高效的元搜索引擎系统SMS(Smart Meta Searchcr),采用检索实例知识库对用户的检索意图进行推理,同时给出一套独特的星级排行评价策略,通过用户行为分析技术为用户提供个性化信息检索服务,以及其在未来搜索引擎个性化、智能化、专业化和多媒体搜索的发展方向所做的探索工作。展开更多
文摘1 引言 World Wide Web是目前全球最大的信息系统,在WWW上查询Web文档主要依赖于Internet上的索引信息系统,如Yahoo、Infoseek、AltaVista、WebCrawler、Excite、Lycos等等。由于WWW太大又没有良好的结构且Web服务器的自治性,所以Web文档的查询难以做到全面而精确。衡量Web文档查询的质量主要有两个方面:①是否能把所有相关的文档资源找出来,不要有所遗漏。
文摘科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜索(Improved Bald Eagle Search,IBES)算法优化双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)的组合水质等级预测模型。首先,采用CRITIC法确定各水质指标的权重,加权求和获得一项综合水质指标,从而提出一种改进的水质评价指标体系,以为BiLSTM提供更丰富、更可靠的水质特征信息。其次,在训练过程中引入Logistic映射和莱维飞行策略,并设计交叉共享及准反向搜索策略优化秃鹰搜索(Bald Eagle Search,BES)算法,以提升其种群多样性,增强寻优能力。最后,通过IBES算法迭代寻找BiLSTM的最佳学习率、隐藏层节点数以及正则化系数的超参数组合,进一步提高其预测水平。结果显示:与IBES-BiLSTM、BES-BiLSTM、GA-BiLSTM、PSO-BiLSTM和BiLSTM等模型相比,CRITIC-IBES-BiLSTM模型进行水质等级预测的准确率、精准率、召回率及F_(1)均最高,且具有更好的稳定性。
文摘With the explosive increase of the network information,people can find information more and more difficultly. The occurrence of the Web search engine overcomes this problem in some degree. This paper tells about the history of the search engine ,the current state of the search engine. Some guidelines about the search engine are analysed and the related checking methods are also given. In this basis, we introduce the trend of the search engine.
文摘With the explosive increase of the network information,it is more and more difficult for people to look up information. The occurrence of the Web search engines overcomes this problem in some degree. However, because different search engines use different mechanisms, scope and algorithms, the repetition of the search results for the same query is no more than 34 %. If wish to get relativly fullscale ,accurate search results,multi-search engines should be used and the meta search engines occur. In this paper ,the meta search engines are surveyed. At first ,the history ,the principles and the elements of the meta search engines are discussed. Then,the related creteria of the meta search engines are analyzed and several typical meta search engines are compared. Finally,on this base,the trend of the meta search engine is introduced.
