在Oracle数据库中如何处理多媒体数据

多媒体不仅改变了数据库的接口 ,使其声、图、文并茂 ,而且也改变了数据库的操作形式 ,多媒体数据库技术、多媒体网络技术为多媒体信息的存储、管理、传递与检索创造了条件。本文介绍了在Oracle数据库中对二进制大数据对象进行处理 ,实现了对多媒体数据的存储和查询     

对PB访问数据库中大对象数据方法的研究

为了快速高效地处理数据库中大对象数据,本文介绍了用PowerBuilder开发数据库应用系统时处理大对象数据的三种方法,并对数据库存储大对象数据的原理进行了分析。实践证明,在Oracle数据库中导入和读取大对象数据的实现过程是最可靠、最安全、最有效的一种方法。     

用PB访问数据库中大对象数据的方法探讨

为了快速高效地处理数据库中大对象数据,介绍了用PowerBuilder开发数据库应用系统时处理大对象数据的3种方法,比较了3种方法的优缺点,对数据库存储大对象数据的原理进行了分析。实践证明,该实现过程是最可靠、最安全、最有效的一种方法。     

自适应云资源大块数据对象并行存取方法

对自适应云资源大数据块对象进行并行存取时,由于没有利用数据挖掘理论构建大数据对象的并行存取模型,导致并行存取的时间长、内存占比高、提取正确率低等问题,由此提出自适应云资源大数据块对象的并行存取方法.利用聚类算法对大数据块对象中的数据进行缺失值填充,并将填充后的数据进行分割处理,获取新的数据集;获取大数据块对象的输入层神经元,计算数据采样梯度函数,结合数据挖掘理论构建大数据块对象的并行存取模型;将自适应云资源大数据块对象放入模型中进行自适应寻优处理,以此完成自适应云资源大数据块对象的并行存取.实验结果表明,利用上述方法对大数据块对象进行并行存取时存取时间短、内存占比低、存取的正确率高.     

基于Huffman编码与XML的大对象数据交换

XML作为异构数据交换的标准格式在数据交换平台中得到了广泛的应用,多媒体数据由于其容量巨大在数据库中往往作为大对象数据来保存,因此在异构数据交换中必然涉及到大对象数据交换的问题。文章讨论了Huffman编码的原理并提出了基于XML使用Huffman编码方式实现大对象数据交换的方法,设计了相应的实现模型,对异构数据库大对象数据交换的实现具有一定的借鉴意义。     

一种访问Access数据库中大数据对象的有效方法

在数据库应用开发过程中，经常要处理大量的大数据对象(如图形、声音文件或带格式的大文本文件等)，如何高效快捷地处理这些大数据对象是开发人员当前所面临的一个难题。本文介绍一种VC通过MFC类库访问Access数据库中的大数据对象的简单有效方法。阐明了VC如何通过MFC ODBC类连接到Access数据库，以及如何利用MFC类库的CLongBinary类和CFile类处理数据库中大对象，并举例说明。     

XML数据的数值对象化及其转化算法

XML数据的结构复杂且具有异构性,数据使用难度大,其文本内容特点使XML数据访问程序难以被有效维护。针对该问题提出数值对象化模型,使用相同算法对所有XML数据进行处理,将XML数据的使用问题转化为面向对象编程语言中的VO值对象处理问题,避免对每类具有不同结构的XML数据文档进行单独解析,增强程序可维护性。工程应用和实验结果验证了该模型的有效性。     

对象-关系数据库对多媒体的支持技术

对象－关系型数据库已成为当今数据库领域研究和发展的热点。文章以多媒体数据管理和应用的需求为出发点,讨论了对象－关系型数据库对多媒体数据的管理方法,即通过对关系数据库管理系统（ＲＤＢＭＳ）进行扩展,使之能支持新引入的用户定义类型（ＵＤＴ）、用户定义函数（ＵＤＦ）、大对象（ＬＯＢ）、关系扩展器（ＲＥＬＡＴＩＯＮＡＬ ＥＸＴＥＮ－ＤＥＲ）等对象－关系模型特色,并通过数据链技术控制机制来实现对数据库及外部文件系统中大量的复杂多媒体数据的管理。这些多媒体扩展机制保留了所有的ＲＤＢＭＳ的长处和优点,增加了对复杂的多媒体应用的支持。     

对象-关系数据库对多媒体的支持技术

对象－关系型数据库已成为当今数据库领域研究和发展的热点。文章以多媒体数据管理和应用的需求为出发点,讨论了对象－关系型数据库对多媒体数据的管理方法,即通过对关系数据库管理系统（ＲＤＢＭＳ）进行扩展,使之能支持新引入的用户定义类型（ＵＤＴ）、用户定义函数（ＵＤＦ）、大对象（ＬＯＢ）、关系扩展器（ＲＥＬＡＴＩＯＮＡＬ ＥＸＴＥＮ－ＤＥＲ）等对象－关系模型特色,并通过数据链技术控制机制来实现对数据库及外部文件系统中大量的复杂多媒体数据的管理。这些多媒体扩展机制保留了所有的ＲＤＢＭＳ的长处和优点,增加了对复杂的多媒体应用的支持。     

Oracle的大对象（LOBs）及其在企业MIS中的应用

介绍了利用Oracle8的大对象来表示多媒体数据，通过JDBC进行操纵，并结合实例说明了实现大对象操纵的关键技术。     

Collaborative Multimedia Presentations in Mobile Environments

Distributed multimedia documents systems, distributed video servers are examples of multimedia presentations involving collaboration among multiple information sources. In such applications, objects have to be retrieved from their sources and presented to users according to specified temporal relationships. Objects retrieval in these collaborative applications is influenced by their presentation times, durations, and network throughput available to their sources. Replication of objects amongst the set of collaborating systems gives a choice for object retrieval. Client going through a multimedia presentation can be in a mobile environment. Here, object retrievals from collaborating servers are carried out by base stations to which the client is attached. Mobile client then downloads objects from the base station.In this paper, we present a graph-search based algorithm for computing and negotiating throughput requirements of collaborating multimedia presentations with replicated objects in a mobile environment. This algorithm maximizes the number of cached objects (that have already been played) for handling operations such as reverse presentation.     

Spatio-temporal composition and indexing for large multimedia applications

Multimedia applications usually involve a large number of multimedia objects (texts, images, sounds, etc.). An important issue in this context is the specification of spatial and temporal relationships among these objects. In this paper we define such a model, based on a set of spatial and temporal relationships between objects participating in multimedia applications. Our work exploits existing approaches for spatial and temporal relationships. We extend these relationships in order to cover the specific requirements of multimedia applications and we integrate the results in a uniform framework for spatio-temporal composition representation. Another issue is the efficient handling of queries related to the spatio-temporal relationships among the objects during the authoring process. Such queries may be very costly and appropriate indexing schemes are needed so as to handle them efficiently. We propose efficient such schemes, based on multidimensional (spatial) data structures, for large multimedia applications that involve thousands of objects. Evaluation models of the proposed schemes are also presented, as well as hints for the selection of the most appropriate one, according to the multimedia author's requirements.     

An Extended Relational Data Model for Multimedia DBMSs

We have extended the canonical relational data model to enable the management of multimedia objects. In an attempt to provide a smooth paradigm shift to multimedia information system development, we have enhanced the relational data model framework with techniques for modeling, storing and manipulating multimedia data. In particular, we have provided a graphical conceptual model for structuring a multimedia document and mapping rules for translating it into an extended relational data schema. Extensions have regarded the management of foreign keys, active components, mechanisms for the management of spatial and temporal relations, and finally functions for handling multimedia presentations. As a consequence, we have also provided extensions to the SQL language to handle these new mechanisms.     

The expressive task specification and adaptive image data handling for mobile applications

An efficient multimedia data handling is a fundamental requirement of mobile multimedia applications. To accommodate this requirement, issues of the available technologies as well as mobile multimedia data access and transfer processes, and the characteristics of the medium to be handled should all be taken into consideration. For this end, these aspects are investigated. The results of the investigation lead to the conclusion that an expressive task specification and adaptive multimedia data handling should be provided. With an expressive task specification, a demand for accessing multimedia object can be described flexibly to enable a minimum handling overhead (thus high performance) and an optimal compromise between performance, cost and quality. Adaptive media handling functionality adapts the service performance according to the medium to be accessed, the available resources and compromise preference of a mobile client, etc. This paper presents the new concepts and methods for these two aspects.     

Modeling and Management of Fuzzy Information in Multimedia Database Applications

In this paper, we firstly present a conceptual data model for multimedia database applications based on ExIFO₂ model. The ExIFO₂ data model is chosen as the conceptual model since it handles complex objects along with their uncertain and imprecise properties. We enhanced this conceptual model in order to meet the multimedia data requirements. In addition to uncertain and imprecise information, we present a way of handling relationships among objects of multimedia database applications. Events that might be extracted from video or audio are also considered in this study. Secondly, the conceptual model is mapped to a logical model, which the fuzzy object-oriented data (FOOD) model is chosen, for storing and manipulating the multimedia objects. This mapping is done in a way that it preserves most of the information represented at the conceptual level. Finally, in this study videos of football (soccer) games is selected as the multimedia database application to show how we handle crisp and fuzzy querying and retrieval of fuzzy and crisp data from the database. A program has been developed to draw ExIFO₂ schemas and to map the schema to FOOD code automatically.     

Cross-media retrieval using query dependent search methods

The content-based cross-media retrieval is a new type of multimedia retrieval in which the media types of query examples and the returned results can be different. In order to learn the semantic correlations among multimedia objects of different modalities, the heterogeneous multimedia objects are analyzed in the form of multimedia document (MMD), which is a set of multimedia objects that are of different media types but carry the same semantics. We first construct an MMD semi-semantic graph (MMDSSG) by jointly analyzing the heterogeneous multimedia data. After that, cross-media indexing space (CMIS) is constructed. For each query, the optimal dimension of CMIS is automatically determined and the cross-media retrieval is performed on a per-query basis. By doing this, the most appropriate retrieval approach for each query is selected, i.e. different search methods are used for different queries. The query dependent search methods make cross-media retrieval performance not only accurate but also stable. We also propose different learning methods of relevance feedback (RF) to improve the performance. Experiment is encouraging and validates the proposed methods.     

在PB9.0和Oracle 9i中实现多媒体数据操作的方法

阐述了多媒体数据库的实现方式，提出了在Oracle中或在PB 9．0中充分利用Oracle的包和PB的支持，LOB数据类型函数能很方便地实现多媒体数据操作。分别提出了Oracle的方法和PB对LOB数据类型存取的方法，并应用在了医疗保险软件中，效果反映良好。     

Fragmental Proxy Caching for Streaming Multimedia Objects

In this paper, a fragmental proxy-caching scheme that efficiently manages the streaming multimedia data in proxy cache is proposed to improve the quality of streaming multimedia services. The novel data-fragmentation method in this scheme not only provides finer granularity caching units to allow more effective cache replacement, but also offers a unique and natural way of handling the interactive VCR functions in the proxy-caching environment. Furthermore, a cache-replacement scheme, based on user request arrival rates for different multimedia objects and the playback rates of these objects, is proposed to address the drawbacks in existing cache-replacement schemes, most of which consider only the user access frequencies in their cache-replacement decisions. In this cache-replacement scheme, a sliding history window is employed to monitor the dynamic user request arrivals, and a tunable-victimization procedure is used to provide an excellent method of managing the cached multimedia data in accordance with different quality-of-service requirements of the streaming multimedia applications. Performance studies demonstrate that the fragmental proxy-caching scheme significantly outperforms other caching schemes, in terms of byte-hit ratio and the number of delayed starts and can be tuned to either maximize the byte-hit ratio or minimize the number of delayed starts     

Delphi4.0操纵Oracle8中大型对象的方法

通过一个具体的实例，介绍了Oracle8数据库系统中的大型对象（LOBs)数据类型的MIS中的应用，详细给出了用Delphi4.0在Client/Sever、Browser/Server结构中操纵Oracle8中4的大型对象字段的方法，并给出了相应的程序段。     

Application-Layer Protocol for Collaborative Multimedia Presentations

Many multimedia presentation applications involve retrieval of objects from more than one collaborating server. Presentations of objects from different collaborating servers might be interdependent. For instance, we can consider distributed video servers where blocks of movies are distributed over a set of servers. Here, blocks of a movie from different video servers have to be retrieved and presented continuously without any gaps in the presentation. Such applications first need an estimate of the available network resources to each of the collaborating server in order to identify a schedule for retrieving the objects composing the presentation. A collaborating server can suggest modifications of the retrieval schedule depending on its load. These modifications can potentially affect the retrieval schedule for other collaborating applications. Hence, a sequence of negotiations have to be carried out with the collaborating servers in order to commit for a retrieval schedule of the objects composing the multimedia presentation. In this paper, we propose an application sub-layer protocol, Resource Lock Commit Protocol (RLCP), for handling the negotiation and commitment of the resources required for a collaborative multimedia presentation application.