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1.
Currently, vertical partitioning has been used in multimedia databases in order to take advantage of its potential benefits in query optimization. Nevertheless, most vertical partitioning algorithms are static; this means that they optimize a vertical partitioning scheme (VPS) according to a workload, but if this workload suffers changes, the VPS may be degraded, which would result in long query response time. This paper presents a set of active rules to perform dynamic vertical partitioning in multimedia databases. First of all, these rules collect all the information that a vertical partitioning algorithm needs as input. Then, they evaluate this information in order to know if the database has experienced enough changes to trigger a performance evaluator. In this case, if the performance of the database falls below a threshold previously calculated by the rules, the vertical partitioning algorithm is triggered, which gets a new VPS. Finally, the rules materialize the new VPS. Our active rule base is implemented in the system DYMOND, which is an active rule-based system for dynamic vertical partitioning of multimedia databases. DYMOND’s architecture and workflow are presented in this paper. Moreover, a case study is used to clarify and evaluate the functionality of our active rule base. Additionally, authors of this paper performed a qualitative evaluation with the aim of comparing and evaluating DYMOND’s functionality. The results showed that DYMOND improved query performance in multimedia databases.  相似文献   

2.
In this paper, we present a new method, called multiview fuzzy querying, which permits to query incomplete, imprecise and heterogeneously structured data stored in a relational database. This method has been implemented in the MIEL software. MIEL is used to query the Sym'Previus database which gathers information about the behavior of pathogenic germs in food products. In this database, data are incomplete because information about all possible food products and all possible germs is not available; data are heterogeneous because they come from various sources (scientific bibliography, industrial data, etc); data may be imprecise because of the complexity of the underlying biological processes that are involved. To deal with heterogeneity, MIEL queries the database through several views simultaneously. To query incomplete data, MIEL proposes to use a fuzzy set, expressing the query preferences of the user. Fuzzy sets may be defined on a hierarchized domain of values, called an ontology (values of the domain are connected using the a kind of semantic link). MIEL also proposes two optional functionalities to help the user query the database: i) MIEL can use the ontology to enlarge the querying in order to retrieve the nearest data corresponding to the selection criteria; and ii) MIEL proposes fuzzy completion rules to help the user formulate his/her query. To query imprecise data stored in the database with fuzzy selection criteria, MIEL uses fuzzy pattern matching.  相似文献   

3.
多媒体对象查询语言及其查询处理   总被引:4,自引:0,他引:4  
文章研究了多媒体数据库的查询需求,提出结构化的多媒体对象查询语言MOQL(multi-media object query language).它能够支持基于类型、结构特征、同步关系、时态关系和内容信息的多媒体查询.以DB2数据库为存储机制,定义了一组代数算子和变换规则,利用它们可以将用户定义的MOQL查询变换为代数表达式,进行代数优化,并将代数查询表达式转换为能够在DB2数据库上运行的DB2SQL和C++查询过程.  相似文献   

4.
In a traditional database system, the result of a query is a set of values (those values that satisfy the query). In other data servers, such as a system with queries based on image content, or many text retrieval systems, the result of a query is a sorted list. For example, in the case of a system with queries based on image content, the query might ask for objects that are a particular shade of red, and the result of the query would be a sorted list of objects in the database, sorted by how well the color of the object matches that given in the query. A multimedia system must somehow synthesize both types of queries (those whose result is a set and those whose result is a sorted list) in a consistent manner. In this paper we discuss the solution adopted by Garlic, a multimedia information system being developed at the IBM Almaden Research Center. This solution is based on “graded” (or “fuzzy”) sets. Issues of efficient query evaluation in a multimedia system are very different from those in a traditional database system. This is because the multimedia system receives answers to subqueries from various subsystems, which can be accessed only in limited ways. For the important class of queries that are conjunctions of atomic queries (where each atomic query might be evaluated by a different subsystem), the naive algorithm must retrieve a number of elements that is linear in the database size. In contrast, in this paper an algorithm is given, which has been implemented in Garlic, such that if the conjuncts are independent, then with arbitrarily high probability, the total number of elements retrieved in evaluating the query is sublinear in the database size (in the case of two conjuncts, it is of the order of the square root of the database size). It is also shown that for such queries, the algorithm is optimal. The matching upper and lower bounds are robust, in the sense that they hold under almost any reasonable rule (including the standard min rule of fuzzy logic) for evaluating the conjunction. Finally, we find a query that is provably hard, in the sense that the naive linear algorithm is essentially optimal.  相似文献   

5.
面向语义信息查询的模糊本体模型   总被引:4,自引:0,他引:4       下载免费PDF全文
杨青  陈薇  闻彬 《计算机工程》2010,36(8):188-190
针对领域知识建模时的模糊性、不确定性与信息查询时的局限性,提出一种基于模糊控制规则的模糊本体模型。利用基于模糊聚类的本体机器学习方法构建模糊控制规则库,通过计算模糊相似矩阵得到模糊概念的语义关联,对词汇相关概念进行语义分析与扩展获取模糊概念间的本质语义关系,实现基于模糊概念属性值的信息查询与语义共用。实验结果表明,该模型在语义查询上有更完善的推理机制,能有效获取语义信息。  相似文献   

6.
As more information sources become available in multimedia systems, the development of abstract semantic models for video, audio, text, and image data is becoming very important. An abstract semantic model has two requirements: it should be rich enough to provide a friendly interface of multimedia presentation synchronization schedules to the users and it should be a good programming data structure for implementation in order to control multimedia playback. An abstract semantic model based on an augmented transition network (ATN) is presented. The inputs for ATNs are modeled by multimedia input strings. Multimedia input strings provide an efficient means for iconic indexing of the temporal/spatial relations of media streams and semantic objects. An ATN and its subnetworks are used to represent the appearing sequence of media streams and semantic objects. The arc label is a substring of a multimedia input string. In this design, a presentation is driven by a multimedia input string. Each subnetwork has its own multimedia input string. Database queries relative to text, image, and video can be answered via substring matching at subnetworks. Multimedia browsing allows users the flexibility to select any part of the presentation they prefer to see. This means that the ATN and its subnetworks can be included in multimedia database systems which are controlled by a database management system (DBMS). User interactions and loops are also provided in an ATN. Therefore, ATNs provide three major capabilities: multimedia presentations, temporal/spatial multimedia database searching, and multimedia browsing  相似文献   

7.
基于内容的多媒体数据库系统引擎CDB   总被引:3,自引:0,他引:3  
CDB(Content-based DataBase)是一种基于内容的多媒体数据库引擎,可以嵌入到通用的对象一关系数据库中,使数据库系统综合支持对多媒体数据的常规和基于内容的壹询.本文首先阐述CDB的体系结构,它把信息检索和数据检索结合到数据库中,支持多媒体数据库的基于内容的建立、操纵和维护;然后给出其层次型内容模型,描述多媒体内容的时空结构特征以及信息线索;最后描述用于CDB的基于内容信息检索技术及其设计和实现的用户壹询和操纵接口,包括示例壹询、主观颜色壹询、视频概要和浏览、扩展SQL内容壹询等.  相似文献   

8.
9.
10.
演员模型:一种多媒体数据表达模型   总被引:3,自引:0,他引:3  
张霞 《软件学报》1996,7(8):471-480
本文提出一种多媒体数据表达模型:演员模型,该模型建立在多媒体数据库概念模型基础之上,基于库所—时间Petri网,描述多媒体对象之间的时态关系,同时引入与变迁相关联的场景表达式,描述多媒体对象之间的空间关系,从而模拟多媒体数据的时空编组,文中形式化地定义了演员模型的抽象模型和实现模型,提出多媒体对象的表达算法以及多媒体数据库的查询模型.  相似文献   

11.
由于越来越多的人开始将视线转移到个人健康体检管理上,使得医院在如何实现快速、有序地对体检管理信息进行处理方面面临着巨大的挑战。通过引入模糊查询算法到体检管理系统中,利用语义词法规则结合专家系统对查询条件信息进行分词处理,用模糊贴近度对已经进行分词的条件信息与数据库中存储的对应数据做贴近度的计算,并按照贴近度降序输出,由此使系统尽可能多地快速、准确地获取查询目标数据,减少数据库的冗余度,提高医院体检管理工作的效率,改变医院原有的体检管理运行方式,确保医院体检工作正常有序地运转。  相似文献   

12.
On Similarity Measures for Multimedia Database Applications   总被引:1,自引:1,他引:0  
A multimedia database query consists of a set of fuzzy and boolean (or crisp) predicates, constants, variables, and conjunction, disjunction, and negation operators. The fuzzy predicates are evaluated based on different media criteria, such as color, shape, layout, keyword. Since media-based evaluation yields similarity values, results to such a query is defined as an ordered set. Since many multimedia applications require partial matches, query results also include tuples which do not satisfy all predicates. Hence, any fuzzy semantics which extends the boolean semantics of conjunction in a straight forward manner may not be desirable for multimedia databases. In this paper, we focus on the problem of ‘given a multimedia query which consists of multiple fuzzy and crisp predicates, how to provide the user with a meaningful overall ranking.’ More specifically, we study the problem of merging similarity values in queries with multiple fuzzy predicates. We describe the essential multimedia retrieval semantics, compare these with the known approaches, and propose a semantics which captures the retrieval requirements in multimedia databases. Received 13 August 1999 / Revised 13 May 2000 / Accepted in revised form 26 July 2000  相似文献   

13.
In this paper, we extend the work of Kraft et al. to present a new method for fuzzy information retrieval based on fuzzy hierarchical clustering and fuzzy inference techniques. First, we present a fuzzy agglomerative hierarchical clustering algorithm for clustering documents and to get the document cluster centers of document clusters. Then, we present a method to construct fuzzy logic rules based on the document clusters and their document cluster centers. Finally, we apply the constructed fuzzy logic rules to modify the user's query for query expansion and to guide the information retrieval system to retrieve documents relevant to the user's request. The fuzzy logic rules can represent three kinds of fuzzy relationships (i.e., fuzzy positive association relationship, fuzzy specialization relationship and fuzzy generalization relationship) between index terms. The proposed fuzzy information retrieval method is more flexible and more intelligent than the existing methods due to the fact that it can expand users' queries for fuzzy information retrieval in a more effective manner.  相似文献   

14.
A multimedia application involves information that may be in a form of video, images, audio, text and graphics, need to be stored, retrieved and manipulated in large databases. In this paper, we propose an object-oriented database schema that supports multimedia documents and their temporal, spatial and logical structures. We present a document example and show how the schema can adress all the structures described. We also present a multimedia query specification language that can be used to describe a multimedia content portion to be retrieved from the database. The language provides means by which the user can specify the information on the media as well as the temoral and spatial relationships among these media.  相似文献   

15.
基于模糊语言方法的信息检索系统的研究   总被引:4,自引:2,他引:2  
该文提出了一个基于模糊语言方法的信息检索系统模型。该系统分为查询界面子系统、数据库子系统和检索子系统三大部分。在查询界面子系统,用布尔表达式表示用户的查询请求,并对每个查询关键词赋予了两种不同语义的语言值权重,该权重表达了用户的模糊检索要求;在数据库子系统,用索引词一文档模糊矩阵表示待检索的文档,对每个索引词。根据其在文档中的出现频率大小。引入了数值权重;在检索子系统,运用模糊语言方法,对用户输入的布尔查询表达式与索引词一文档模糊矩阵进行自底向上的模糊匹配,最后返回满足用户要求的检索结果。相对于传统的基于查询关键词精确匹配的检索系统而言,该系统能较好地满足用户查询要求中的灵活性。  相似文献   

16.
17.
多媒体信息查询和检索系统MIRc   总被引:2,自引:0,他引:2  
多媒体信息的内容管理是信息化社会的重要基础技术之一,多媒体信息查询和检索系统MIRc是我们设计和实现的一种原型系统。本文首先介绍MIRc系统的体系结构,它能够有效地支持多媒体信息库的建立、操纵和维护;阐述能够描述多媒体内容和时空结构特征,以及信息线索的数据模型;最后介绍用于MIRc的基于内容检索技术及其设计和实现的用户查询接口。  相似文献   

18.
BilVideo: Design and Implementation of a Video Database Management System   总被引:1,自引:1,他引:0  
With the advances in information technology, the amount of multimedia data captured, produced, and stored is increasing rapidly. As a consequence, multimedia content is widely used for many applications in today’s world, and hence, a need for organizing this data, and accessing it from repositories with vast amount of information has been a driving stimulus both commercially and academically. In compliance with this inevitable trend, first image and especially later video database management systems have attracted a great deal of attention, since traditional database systems are designed to deal with alphanumeric information only, thereby not being suitable for multimedia data.In this paper, a prototype video database management system, which we call BilVideo, is introduced. The system architecture of BilVideo is original in that it provides full support for spatio-temporal queries that contain any combination of spatial, temporal, object-appearance, external-predicate, trajectory-projection, and similarity-based object-trajectory conditions by a rule-based system built on a knowledge-base, while utilizing an object-relational database to respond to semantic (keyword, event/activity, and category-based), color, shape, and texture queries. The parts of BilVideo (Fact-Extractor, Video-Annotator, its Web-based visual query interface, and its SQL-like textual query language) are presented, as well. Moreover, our query processing strategy is also briefly explained.This work is partially supported by the Scientific and Research Council of Turkey (TÜBİTAK) under Project Code 199E025, Turkish State Planning Organization (DPT) under Grant No. 2004K120720, and European Union under Grant No. FP6-507752 (MUSCLE Network of Excellence Project).  相似文献   

19.
针对油气井工程领域关系数据库,提出一种基于语义视图的SPARQL-SQL查询转换方法.该方法采用特定本体描述数据源关系模式,通过RDF三元组形式,将关系表定义为领域本体之上的语义查询视图,从而建立数据源与本体之间的映射关系,并根据语义映射信息,将提交的SPARQL语句进行解析与查询重写,转换为面向关系数据源的SQL语句.通过实现油气井虚拟数据中心,验证了该方法的可行性与有效性,并获得了良好的应用效果.  相似文献   

20.
基于Windows平台和Access数据库,应用PowerBuilder语言开发纳税服务多媒体查询系统是一项全新的实践工作。纳税服务多媒体查询系统基于触摸屏技术,面向公众,界面友好,操作简便,可视化程度高。利用本系统可以查询办税服务流程、税收法规知识和辖区企业的纳税申报情况。  相似文献   

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