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图数据模型广泛应用于各种具有复杂关联数据的领域.针对现有音乐数据模型与查询语言在功能上的缺陷,首先提出了一个基于图的音乐数据模型Gra-MM,用图数据模型对复杂音乐数据进行建模,定义了图逻辑数据结构以及相关的图代数操作,然后给出了建立在Gra-MM之上的音乐数据查询语言Gra-MQL,定义了查询语言的BNF定义.Gra-MQL能够较好地处理音乐数据之间的复杂关联,同时具有音乐元数据检索和音乐内容数据检索能力,从而满足用户对音乐数据不同层次的查询需求,克服了传统图数据查询语言对复杂关联数据的表达能力有限、不能直接应用于音乐内容检索等不足.最后对实现的音乐数据库原型系统进行了介绍,对原型系统进行测试并给出实验数据,证明了模型以及查询语言的可行性. 相似文献
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肖铮 《计算机技术与发展》2020,(5):70-75
以RDF结构为基础的数据网的发展中,高效数据检索成为关键问题之一。形式化查询语言(如SPARQL)因其语法的复杂性及查询本体的相关性阻碍其效用的发挥,迫切需要新的方法或工具实现以自然语言为基础(如关键字检索)的检索。形式化查询语言是检索这类结构化数据的有效方式,用户习惯自然语言为基础的检索方式。因而如何自动将关键词为基础的检索方式转换成以形式化查询为基础的检索方式是实现数据网的重要一环。关联数据的自然语言查询方法自动将自然语言查询转换成SPARQL查询,提高系统的有效性和效率。文中在抽象转换度量模型的基础上,以本体为基础构建查询语义图及实现语义消歧,构建SPARQL查询。实验结果表明,该方法具有更高的召回率、精度及更低的时间消耗。 相似文献
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模糊关系数据库查询语言FSQL 总被引:1,自引:0,他引:1
模糊数据库是模糊信息处理系统的重要组成部分。本文以SQL语言为基础,设计了模糊关系数据库查询语言FSQL。FSQL语言采用了模糊值模糊关系数据模型,提供了相应的模糊数据定义与模糊数据操纵功能。为了便于模糊信息的表示和管理,FSQL语言增加了模糊数据类型,如简单标量型、模糊标量型、简单数集、模糊数集等。另外,为了便于模糊查询,扩充了模糊比较库函数及自定义隶属函数。 相似文献
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WWW实际上是一个巨大的异构分布式数据库系统。为了支持高级的、健壮的和可靠的应用,在WWW上应当加强其数据库的功能。文中引进了新的机制和概念以便将数据库的功能移植到WWW上,并对涉及到的WWW查询处理和数据稳定性的概念进行了探讨。 相似文献
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In this paper, a Graph-based semantic Data Model (GDM) is proposed with the primary objective of bridging the gap between the human perception of an enterprise and the needs of computing infrastructure to organize information in some particular manner for efficient storage and retrieval. The Graph. Data Model (GDM) has been proposed as an alternative data model to combine the advantages of the relational model with the positive features of semantic data models. The proposed GDM offers a structural representation for interacting to the designer, making it always easy to comprehend the complex relations amongst basic data items. GDM allows an entire database to be viewed as a Graph (V, E) in a layered organization. Here, a graph is created in a bottom up fashion where V represents the basic instances of data or a functionally abstracted module, called primary semantic group (PSG) and secondary semantic group (SSG). An edge in the model implies the relationship among the secondary semantic groups. The contents of the lowest layer are the semantically grouped data values in the form of primary semantic groups. The SSGs are nothing but the higher-level abstraction and are created by the method of encapsulation of various PSGs, SSGs and basic data elements. This encapsulation methodology to provide a higher-level abstraction continues generating various secondary semantic groups until the designer thinks that it is sufficient to declare the actual problem domain. GDM, thus, uses standard abstractions available in a semantic data model with a structural representation in terms of a graph. The operations on the data model are formalized in the proposed graph algebra. A Graph Query Language (GQL) is also developed, maintaining similarity with the widely accepted user-friendly SQL. Finally, the paper also presents the methodology to make this GDM compatible with the distributed environment, and a corresponding query processing technique for distributed environment is also suggested for the sake of completeness. 相似文献
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Baozhu Liu Xin Wang Pengkai Liu Sizhuo Li Xiaowang Zhang Yajun Yang 《International Journal of Software and Informatics》2021,11(1):91-116
Knowledge graph is an important cornerstone of artificial intelligence, which currently has two main data models: RDF graphs and property graphs. There are several query languages on these two data models, including SPARQL on RDF graphs and Cypher on property graphs. Over the last decade, various communities have developed different data management methods for RDF graphs and property graphs. Inconsistent data models and query languages hinder the wider application of knowledge graphs. In this paper, we propose a knowledge graphy database (KGDB) system with unified data model and query language. (1) We work out a unified storage scheme based on the relational model that supports the efficient storage of RDF graphs and property graphs, catering to the smooth storage and query of knowledge graph data. (2) The characteristic set-based clustering is used in KGDB for the storage of typeless entities. (3) It realizes the interoperability of SPARQL and Cypher by enabling them to operate on the same knowledge graph. Extensive experiments on real-world datasets and synthetic datasets reveal that KGDB is more efficient than existing knowledge graph database management systems in storage management and query efficiency. KGDB saves 30% of the storage space on average compared with gStore and Neo4j. In addition, KDGB is two orders of magnitude faster than gStore and Neo4j in the query of the real-world datasets, seen from experiments on the query of basic graph pattern matching. 相似文献
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Peter M.D. Gray Suzanne M. Embury Kit Y. Hui Graham J.L. Kemp 《Journal of Intelligent Information Systems》1999,12(2-3):113-137
We describe how to express constraints in a functional (semantic) data model, which has a working implementation in an object database. We trace the development of such constraints from being integrity checks embedded in procedural code to being something declarative and self-contained, combining data access and computation, that can be moved around into other contexts in intelligent distributed systems. We see this as paralleling and extending the original vision of functions as values in functional programming systems. It is greatly helped by using a referentially transparent functional formalisation. We illustrate these ideas by showing how constraints can move around within database systems (Colan & Angelic Daplex), being transformed for various uses, or even moved out into other systems and fused into a specification for a configuration problem. We look forward to future directions involving Agents. 相似文献
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面向空间数据库引擎的扩充数据模型及其操纵语言GSQL 总被引:9,自引:3,他引:9
面向空间数据库引擎的扩充数据模型将点、线、面等几何数据类型作为系统的基本数据类型,其操纵语言GSQL在标准SQL语言基础上支持几何数据和属性数据的定义、检索、存储和管理。关系数据库元数据表提供了对象—关系模型转换接口。 相似文献
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岳根霞 《电脑编程技巧与维护》2012,(14):50-51
从多媒体数据的特征研究出发,分别介绍了面向对象的数据模型、NF2数据模型、超媒体数据模型、信息元等多媒体数据模型,研究基于内容的图像、视频等多媒体媒体的的检索方法,对建立多媒体数据库系统具有普遍的指导意义和实用价值。 相似文献
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本文探讨了为数据库查询提供自然语言接口的可能性,给出了查询流程、基于状态转换图的词法分析和语法分析方法、将疑问句转换成SOL查询语句的方法以及由查询结果生成回答句的方法。 相似文献
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实时数据库系统的关系数据模型 总被引:3,自引:2,他引:3
实时数据库系统的定时限制包括数据的定时限制和事务的定时限制。本文详细讨论了实时数据的各种时特征,包括数据的外部有效期、相互一致性、采用样同步性、数据截止期等;在引出元组生命周期其映射概率的基础上,建立了实时数据库系统的地关系数据模型RTRDM。 相似文献
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一种基于统计语义聚类的查询语言模型估计 总被引:2,自引:0,他引:2
如何有效生成文档聚类并使用聚类信息提高检索效果是信息检索中的重要研究课题.如果假设文档中存在若干隐含的独立主题,那么文档可以看成是由这些隐含的独立主题混合噪声相互作用的结果.基于这个假设提出了一种基于独立分量分析的语义聚类技术,试图借助于独立分量分析的良好主题区分能力,将一组文档按照实际隐含的主题在语义空间上聚类.在语言模型的框架下,语义主题聚类将由用户初始查询按照一定的度量方式激活.利用激活语义聚类的信息估计一个反馈语义主题模型,并与初始查询模型一起形成新的查询模型.在5个TREC数据集上的实验结果表明:基于统计语义聚类估计的查询模型相比传统的查询模型以及其他基于聚类的语言模型在检索性能上有显著性提高.其主要原因是应用了和用户查询最相似的语义聚类信息来估计查询模型. 相似文献
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隐私已经越来越受到人们的重视.论文首先介绍了隐私和隐私数据库的概念,然后根据隐私数据类型的不同,构建了隐私数据类型的层次结构;最后,提出了一种新的隐私定义及其建模方法,并对单拥有者隐私数据类型和多拥有者隐私数据类型进行了形式化描述. 相似文献
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本文根据面向对象的工程数据库管理系统(OOEDBMS)的特点,定义了面向对象的工程数据查询语言(OSQL)的模型,并分析,归纳了它的功能、特点,最后通过对我们CAD中心开发的面向对象的工程数据库管理系统OOEDBMS的结构、设计以及建立在其上的查询语言OSQL实现的介绍,对OSQL与数据库连接、抽象数据类型操纵、复杂语义表示、工作区设计等问题进行了一些有益的探讨,并对OSQL的进一步改进、扩充提出了设想。 相似文献
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Most documents available over the Web conform to the HTML specification. Such documents are hierarchically structured in nature. The existing data models for the Web either fail to capture the hierarchical structure within the documents or can only provide a very low level representation of such hierarchical structure. How to represent and query HTML documents at a higher level is an important issue. In this paper, we first propose a novel conceptual model for HTML. This conceptual model has only a few simple constructs but is able to represent the complex hierarchical structure within HTML documents at a level that is close to human conceptualization/visualization of the documents. We also describe how to convert HTML documents based on this conceptual model. Using the conceptual model and conversion method, one can capture the essence (i.e., semistructure) of HTML documents in a natural and simple way. Based on this conceptual model, we then present a rule–based language to query HTML documents over the Internet. This language provides a simple but very powerful way to query both intra–document structures and inter–document structures and allows the query results to be restructured. Being rule–based, it naturally supports negation and recursion and therefore is more expressive than SQL–based languages. A logical semantics is also provided. 相似文献