共查询到19条相似文献，搜索用时 156 毫秒
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合理有效地管理实验设备有利于提高设备的利用率,现将时间图查询用于实验设备的管理,可以丰富查询的语义,提高设备的查询效率.将设备的使用情况抽象成一个大的时间图,将用户的查询请求转换为一个查询图,利用图匹配技术查询出相关的结果.为实现查询图的匹配,提出了3种相关算法:朴素匹配算法(NM)、基于BFS的点匹配算法(BVM)和... 相似文献
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王荣华 《西安文理学院学报》2019,(4)
资源描述框架广泛用于描述资源及其关系,资源描述框架图是最常用的资源描述框架数据表示方式之一.采用不一致概率的资源描述框架图对数据进行形式化处理,并探讨图匹配问题.给定查询图,从不一致概率的资源描述框架图中进行子图的检索,并获得高质量分数.为了提高查询效率,设计了一个有效的剪枝策略.通过大量的实验验证了所提出算法的有效性. 相似文献
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为了解决语义Web服务匹配方法主要针对服务IO描述的匹配, 导致匹配结果较为片面的问题, 提出了一种基于描述逻辑的语义Web服务IOPE描述及匹配方法. 具体使用描述逻辑概念标注服务IO, 以描述逻辑断言库刻画服务PE. 进行服务匹配时, 利用描述逻辑TBox概念包含检测确定服务请求与广告IO之间的包含关系; 利用描述逻辑ABox一致性检测推理, 判断服务请求与广告PE之间的逻辑蕴含关系; 依据此蕴含关系, 将PE匹配情况划分为4种, 即Exact, Perfect, Side-effect和Common匹配, 用以对匹配结果进行有意义的排序. 实验结果表明, 所提方法在召回率与现有方法相当的情况下, 具有更高的查准率. 相似文献
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图像的抽象描述和特征提取是基于内容的图像检索系统中需要解决的关键问题之一,文章提出了一种图像信息熵和分形编码相结合的图像检索方法．首先,计算图像库中的各幅图像的信息熵,比较设定的阈值对图像库进行预分类;其次．利用Jacquin方法计算得到查询图像的分形IFS编码,应用到图像库同类的图像进行分形迭代解码;最后,计算解码图像与查询图像的相似距离得到检索结果．实验结果表明,与直接像素值相似匹配方法相比,该法在基本保证图像检索效率的前提下,极大地提高了检索时间． 相似文献
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目前,常用的全文搜索引擎都是基于关键词检索的,其查准率和查全率都较低,并且返回记录太多,重复信息过多,使得搜索引擎的查询效率很低。基于此,提出了一种基于本体的搜索引擎模型,通过提取的文档中概念,确定其所属的领域本体,以此归类,并用文档—概念匹配系数建立索引。搜索时,采用基于概念匹配的方式进行检索,对属于不同领域本体的文档,分类输出。提高搜索引擎的查准率和查全率,减少冗余信息,从而提高搜索引擎的查询效率。 相似文献
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为了改善目前船舶装备远程维修技术支援系统缺乏知识查询、相似案例检索、案例推理等知识管理缺陷,提出基于本体构建的远程维修技术支援知识库系统。通过对故障案例进行分析,提取案例特征,并运用属性相似度计算,进行案例检索匹配;若检索到的故障案例不适用,则运用模糊C均值法对故障案例库进行处理并得到精简案例库,同时运用神经网络对其进行训练,使系统形成案例推理能力,再结合专家经验,形成实用的故障解决方案。研究结果表明,该方法解决了目前船舶装备远程维修技术支援系统缺乏知识查询、相似案例检索、案例推理等问题,提高了船舶装备远程维修技术支援的知识管理能力和效率。 相似文献
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分析了现有信息系统中检索数据时直接输入检索词的不足,提出了基于汉字拼音首字母的查询方法,以汉字拼音首字母串替代检索词,并针对重码问题进行了分析研究,得出一种可行的编码方案.该方法对检索词是姓名、地名、商品名等专用名的查询具有很好的实用价值,能显著提高查询效率. 相似文献
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支持语义web模糊本体的描述逻辑 总被引：7，自引：0，他引：7
为实现语义web上包含复杂模糊知识的模糊本体的表示和推理,提出了一种描述逻辑的模糊扩展———支持比较表达式的模糊描述逻辑(FCDLs).给出FCDLs语法和语义的形式化定义,并规定FCDLs知识库中的公理和断言形式.FCDLs将模糊描述逻辑(FDLs)中的模糊概念和扩展模糊描述逻辑(EFDLs)中的截概念结合在同一理论中,并将截概念扩展为比较截概念,从而支持对实际中经常用到的模糊隶属度之间比较表达式的描述,而其他的描述逻辑模糊扩展均不支持比较表达式.FCDLs具有比FDLs和EFDLs更强的表达能力,能够表示复杂的模糊知识并基于它们完成推理任务.因此FCDLs可实现语义web上包含复杂模糊知识的模糊本体的表示和推理. 相似文献
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CAI Ke-ke BU Jia-jun CHEN Chun QIU Guang 《浙江大学学报(A卷英文版)》2007,8(6):871-882
This paper explores the application of term dependency in information retrieval (IR) and proposes a novel dependency retrieval model. This retrieval model suggests an extension to the existing language modeling (LM) approach to IR by introducing dependency models for both query and document. Relevance between document and query is then evaluated by reference to the Kullback-Leibler divergence between their dependency models. This paper introduces a novel hybrid dependency structure, which allows integration of various forms of dependency within a single framework. A pseudo relevance feedback based method is also introduced for constructing query dependency model. The basic idea is to use query-relevant top-ranking sentences extracted from the top documents at retrieval time as the augmented representation of query, from which the relationships between query terms are identified. A Markov Random Field (MRF) based approach is presented to ensure the relevance of the extracted sentences, which utilizes the association features between query terms within a sentence to evaluate the relevance of each sentence. This dependency retrieval model was compared with other traditional retrieval models. Experiments indicated that it produces significant improvements in retrieval effectiveness. 相似文献
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Search engines have greatly helped us to find the desired information from the Internet. Most search engines use keywords matching technique. This paper discusses a Dynamic Knowledge Base based Search Engine (DKBSE), which can expand the user's query using the keywords' concept or meaning. To do this, the DKBSE needs to construct and maintain the knowledge base dynamically via the system's searching results and the user's feedback information. The DKBSE expands the user's initial query using the knowledge base, and returns the searched information after the expanded query. 相似文献
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韩腊萍 《广东技术师范学院学报》1998,(4)
本文在了解分布式数据库概念及分布式查询优化方法的基础上,主要讨论了如何利用语义信息对分布查询进行优化,以期达到提高查询效率,缩短响应时间的目的。 相似文献
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郑晓霞 《牡丹江教育学院学报》2006,(1):106-107
传统的基于内容的图像检索方法提取图像全局特征,缺乏高层语义信息,无法很好地满足用户的检索要求。本文深入研究基于区域的检索方法,该方法能够更好地表达用户的查询要求,在语义层次上理解图像、检索图像,是基于内容的图像检索的一种行之有效的方法。 相似文献
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基于树的包容匹配思想,把积件的查询转化为查询树与积件标注树之间的匹配.通过研究积件查询的特点,提出积件标注树匹配的3个定理.在此基础上,提出积件查询的逆路径字符串匹配算法.该算法从叶节点开始进行匹配查找,同时考虑从叶节点到根节点的路径长度关系,能尽早终止不能匹配成功的路径,避免了字符串的循环反复查找,同时利用同一路径长度下字符串按字典排序,跳过大量不可能匹配的路径.实验结果表明,此方法在保持积件查找速度的前提下,能有效提高积件的查全率和查准率. 相似文献
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The present study investigated the utility of an instructional strategy known as the query method for enhancing learning outcomes in computer-based training. The query method involves an embedded guided, sentence generation task requiring elaboration of key concepts in the training material that encourages learners to ‘stop and think’ about the information already presented before proceeding to new concepts. This study also investigated the effect of varying the level of elaboration (low or high) prompted by the queries. Fifty-one undergraduate students from the general psychology department subject pool at a major university in the southeastern United States received instruction on the basic principles of flight via one of three versions of a computer-based tutorial (no query, low-level elaboration query, or high-level elaboration query). Participants had no prior knowledge or previous experience with the aviation domain. A one-way between-groups design was employed, with the query method serving as the independent variable and a sample size of 17 per condition. Dependent variables included knowledge organization, knowledge acquisition, and instructional efficiency. Overall, results showed that incorporating low-level elaboration queries into the training resulted in improved organization, integration, and application of task-relevant knowledge and higher instructional efficiency. High-level elaboration queries consistently failed to produce significantly better post-training outcomes, possibly due to the increased cognitive load imposed on learners during training. The discussion centers on theoretical and practical implications for promoting and assessing learning outcomes in computer-based training. 相似文献
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基于内容自动扩展的多示例查询图像检索技术 总被引：1，自引：0，他引：1
为了缩短基于内容图像检索存在的"语义鸿沟",提出了一种自动扩展的多示例查询技术.该技术将传统检索使用的单一查询图像自动扩展为多个查询示例,从而包含了更多的与语义相关的图像特征.对这些查询示例进行检索,并融合检索结果,可以获得更多相关图像.扩展主要利用了一般检索算法的查准率-查全率曲线特点,对原始查询结果的图像特征距离应用K-均值聚类算法,确定多个查询示例图像.实验结果表明该方法可以显著提高原有检索算法的查全率和查准率. 相似文献
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Property path is the latest navigational extension of the standard query language SPARQL 1.1 for the Semantic Web.However,in the existing SPARQL query systems which support property path,the query efficiency is very low and does not support reasoning.This paper proposes a new existential semantics which has polynomial-time evaluation complexity and an equivalent relationship with the current semantics,and transforms the property path expressions to the extended nested regular expressions based on the existential semantics and proves the semantic equivalence after the transformation considering the RDFS semantics.The property path query engine is achieved by implementing the nested regular expressions algorithm and the transformation rules from the property path expressions to the nested regular expressions,which maintains the syntax simplicity of property path and the goal-oriented polynomial-time reasoning to avoid computing the RDF graph closure.The experiment results not only show the characteristics of query engine based on the existential semantics in efficiency and reasoning,but also further validate the equivalence between the results based on current semantics and those based on the existential semantics for property path after the removal of duplicate values. 相似文献