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《内蒙古科技与经济》2019,(21)
OPAC(开放公共查询目录)系统是图书馆提供的重要服务。本文探究了一种基于TF-IDF和余弦相似度的OPAC系统的实现,该系统通过对图书数据进行分词和TF-IDF向量化,进而利用词向量的余弦相似度作为评估依据,以实现为读者提供最接近的咨询结果,克服了传统的基于数据库关键词检索的OPAC系统检索不够灵活、无法实现结果有效聚合、无法处理自然语言检索需求的缺点,具有一定的优越性。 相似文献
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针对目前常用的信息检索算法普遍存在查询性能不高的问题。本文提出了一种基于AWAR算法的信息检索扩展查询模型,该模型首先采用传统向量空间模型算法对检索目标进行初检,然后利用最小完全加权置信度阈值生成完全加权关联规则,最后根据规则提取扩展词,得到查询结果。实验表明,基于AWAR算法的信息检索扩展查询模型的检索性能比传统向量空间模型算法和基于局部上下文分析的查询扩展的检索算法要高。 相似文献
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针对传统方法应用于云计算数据查询服务时的不足,提出基于单个基因模糊化的云计算查询算法。在云计算环境下,找到数据库中的查询请求的目标节点,通过把单个基因位的理论引入到传统的模糊计算中,定义云计算服务节点的数据搜索模型,利用数据评判模糊度函数,使不同尺度因子下的数据查询模糊度函数对应着该尺度下不同输出,数据查询模糊度函数表示经过尺度伸缩的查询结果输出。模糊度函数的最大值对应了云计算环境下数据查询完全匹配的输出。实验结果表明,该方法在查询的数据质量、服务节点的负载能力以及查询的目标长度方法要优于传统的方法。 相似文献
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基于主题偏好的个性化检索模型研究 总被引：1，自引：0，他引：1
随着互联网信息资源日益增多,个性化检索成为了信息检索领域的研究热点.传统的个性化检索利用网页内容形成的向量空间模型来描述用户兴趣,使得用户的查询响应较慢,修正用户兴趣计算量大.由此提出基于主题偏好的个性化检索模型,用户兴趣由用户的主题偏好来表示,结合主题敏感的PageRank算法对检索结果排序.旨在更好地体现用户兴趣,并简化计算,减少查询响应时间. 相似文献
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提出一种新颖的基于特征融合的灰度图像检索算法,该算法将图像按一定步长量化并映射为n阶频率矩阵,然后融合矩阵第一、第二奇异值向量的信息得到图像复特征向量,最后以余弦相似度作为图像检索的相似度度量.实验数据分析表明,算法在检索性能上优于传统的颜色直方图法. 相似文献
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云计算数据预取算法设计是实现云平台环境下通信链路优化和任务调度均衡分配的基础技术。在传统的云计算据查询模式下,当由于缓存空间不足而导致新的缓存数据无法进入缓存时,导致数据预取拥堵,性能不好。提出一种基于Monte Carlo熵权决策的云计算数据预取算法,构建云计算数据查询模板模型,进行Hybrid缓存置换数据预取前置处理,采用Monte Carlo熵权决策方法,把云计算预取信号从缓存域变换到波束域,构建置换函数,实现了对算法的改进。仿真实验研究得出,该算法通过熵权特征提取,进行云计算数据预取决策,提高了云计算数据预取性能,大数据访问延迟率降低,云计算数据存取和调度效率提高,保真率较好。 相似文献
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本文主要研究了查询语义树的生成策略、用户查询语义的提取机制，以及查询语义树中语义边界的确定方法。通过查询语义树产生候选扩展词，再计算候选扩展词与所有查询项在初检局部文档集合中的共现度，用以评估扩展词质量，使得扩展词与用户查询所蕴涵的主题具有较强的语义相关性。实验结果表明，与传统向量空间模型检索算法比较，查询性能有明显的改善。 相似文献
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We present an image retrieval framework based on automatic query expansion in a concept feature space by generalizing the vector space model of information retrieval. In this framework, images are represented by vectors of weighted concepts similar to the keyword-based representation used in text retrieval. To generate the concept vocabularies, a statistical model is built by utilizing Support Vector Machine (SVM)-based classification techniques. The images are represented as "bag of concepts" that comprise perceptually and/or semantically distinguishable color and texture patches from local image regions in a multi-dimensional feature space. To explore the correlation between the concepts and overcome the assumption of feature independence in this model, we propose query expansion techniques in the image domain from a new perspective based on both local and global analysis. For the local analysis, the correlations between the concepts based on the co-occurrence pattern, and the metrical constraints based on the neighborhood proximity between the concepts in encoded images, are analyzed by considering local feedback information. We also analyze the concept similarities in the collection as a whole in the form of a similarity thesaurus and propose an efficient query expansion based on the global analysis. The experimental results on a photographic collection of natural scenes and a biomedical database of different imaging modalities demonstrate the effectiveness of the proposed framework in terms of precision and recall. 相似文献
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Combining the evidence of different relevance feedback methods for information retrieval 总被引：2，自引：0，他引：2
Joon Ho Lee 《Information processing & management》1998,34(6):681-691
It has been known that retrieval effectiveness can be significantly improved by combining multiple evidence from different query or document representations, or multiple retrieval techniques. In this paper, we combine multiple evidence from different relevance feedback methods, and investigate various aspects of the combination. We first generate multiple query vectors for a given information problem in a fully automatic way by expanding an initial query vector with various relevance feedback methods. We then perform retrieval runs for the multiple query vectors, and combine the retrieval results. Experimental results show that combining the evidence of different relevance feedback methods can lead to substantial improvements of retrieval effectiveness. 相似文献
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“云图书馆”平台的架构与实现 总被引：7，自引：0，他引：7
通过对山西财经大学＂云图书馆＂平台技术与应用的探讨分析,论述了图书馆云计算平台的基础架构和功能,探讨了图书馆进入云计算平台的策略和途径,提出了图书馆向云计算平台迁移的内容与方法,为图书馆从设备、应用和服务等资源全面向云计算转变提出了具体的方向。Abstract： Based on the analysis of the technology and application of the＂cloud library＂platform in Shanxi University of Finance and Economics,this paper discusses the basic architecture and function of the cloud computing platform in library,explores the strategies and approaches for library to enter into the cloud computing platform, and brings forward the content and method for library to migrate to the cloud computing platform. The paper gives specific directions for transforming the library into cloud computing completely from the perspective of device,application and service. 相似文献
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基于服务关系统计的数字图书馆云服务模式研究 总被引：1，自引：0，他引：1
云计算环境下,数字图书馆云服务平台系统要求具有更高的可扩展性、可靠性和可用性。随着数字图书馆云服务平台与云服务模式的发展,读者对云阅读服务的需求不断增多。本文首先分析了云计算环境下数字图书馆云服务模式与风险问题。然后,提出了基于服务关系统计的数字图书馆云服务模式。 相似文献
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《Information processing & management》2016,52(5):873-884
OCR errors in text harm information retrieval performance. Much research has been reported on modelling and correction of Optical Character Recognition (OCR) errors. Most of the prior work employ language dependent resources or training texts in studying the nature of errors. However, not much research has been reported that focuses on improving retrieval performance from erroneous text in the absence of training data. We propose a novel approach for detecting OCR errors and improving retrieval performance from the erroneous corpus in a situation where training samples are not available to model errors. In this paper we propose a method that automatically identifies erroneous term variants in the noisy corpus, which are used for query expansion, in the absence of clean text. We employ an effective combination of contextual information and string matching techniques. Our proposed approach automatically identifies the erroneous variants of query terms and consequently leads to improvement in retrieval performance through query expansion. Our proposed approach does not use any training data or any language specific resources like thesaurus for identification of error variants. It also does not expend any knowledge about the language except that the word delimiter is blank space. We have tested our approach on erroneous Bangla (Bengali in English) and Hindi FIRE collections, and also on TREC Legal IIT CDIP and TREC 5 Confusion track English corpora. Our proposed approach has achieved statistically significant improvements over the state-of-the-art baselines on most of the datasets. 相似文献
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云制造平台是以新一代信息技术为支撑,为企业提供网络化制造服务的重要载体.研究服务创新的机理与路径,是提高其服务能级和服务效率的基本前提.在梳理国内外相关研究成果的基础上,以云计算技术作为外生变量,以服务概念创新、服务流程创新、服务界面创新为内生变量,构建提升云制造平台服务创新绩效的结构方程模型;通过对我国各省区市云制造平台的问卷调查,采用最大似然估计法进行统计分析.研究结果表明:云制造平台服务创新存在两条创新路径,分别是“云计算一服务概念创新—服务绩效提升”和“云计算—服务界面创新—服务绩效提升”.该成果为云制造平台的运营与发展提供理论支撑和方法借鉴. 相似文献
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《Information processing & management》2001,37(1):119-145
This study attempted to use semantic relations expressed in text, in particular cause-effect relations, to improve information retrieval effectiveness. The study investigated whether the information obtained by matching cause-effect relations expressed in documents with the cause-effect relations expressed in users’ queries can be used to improve document retrieval results, in comparison to using just keyword matching without considering relations.An automatic method for identifying and extracting cause-effect information in Wall Street Journal text was developed. Causal relation matching was found to yield a small but significant improvement in retrieval results when the weights used for combining the scores from different types of matching were customized for each query. Causal relation matching did not perform better than word proximity matching (i.e. matching pairs of causally related words in the query with pairs of words that co-occur within document sentences), but the best results were obtained when causal relation matching was combined with word proximity matching. The best kind of causal relation matching was found to be one in which one member of the causal relation (either the cause or the effect) was represented as a wildcard that could match with any word. 相似文献
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随着电力行业和电力市场的快速发展,电力工程项目的竞争日益激烈,因此对电力工程项目管理水平的要求也不断提高。云计算是一种以互联网为中心的新兴网络应用模式,能显著改变网络服务的模式,利用它来构建电力工程项目管理系统能带来低成本、高性能等特点。在分析电力工程项目管理特点的基础上设计一个分层的电力工程项目管理系统模型,详细介绍该模型的功能结构以及基于云计算平台——Google Sites的系统实现方法。该方法体现了利用云平台来搭建网络化的电力工程项目管理系统的便捷性与高效性,为电力工程项目管理的信息化和网络化建设提供了一种新的参考。 相似文献
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云计算产业空间格局集聚模式与创新效应研究 《科学学研究》2022,40(4):619-631
云计算是国家“新基建”战略的重要支点。云计算产业空间组织机理存在自上而下政府引导和自下而上企业自组织的双重特性，政府提升产业集聚的地区政策和云计算虚拟化、网络化技术属性之间看似矛盾的关系，是引发本文探索的起点。利用2010-2016年上海市1637家云计算企业数据，描绘城市内部云计算产业空间特性，并分析不同集聚模式对企业创新的影响效应。研究发现：（1）上海云计算产业呈现中心集聚、多点联动的空间格局，随着产业链向后端延伸，企业的空间分布越向中心城区集聚。（2）云计算产业仍然具有地理性，产业链内部专业化集聚和多样化集聚对不同技术类型企业创新的影响呈现梯度变化特征。政府应审视产业链内部不同集聚模式的创新效应差异性，进一步优化产业空间布局，促进创新资源在空间上的有效配置。 相似文献