| 摘要: |
| 本文形式化地提出了一种适用于多媒体对象的概念模型OMCOM．文中首先分析了多媒体数据模拟的特殊性，探讨了现有的多媒体数据模型的不足．从而提出了把多媒体数据模拟划分为概念与表达两级模拟的思想．概念级模拟多媒体对象的内容与结构；表达级模拟其表达，包括多媒体对象之间的时态关系和空间关系．OMCOM就是一种用于实现概念级模拟的模型．然后根据多媒体概念模拟的需求，形式化地定义了OMCOM的各个构成要素．最后根据OMCOM实例的格性质，建立了多媒体对象在概念级的运算体系——对象代数，形式化地定义了其中的各种运算以及对象代数表达式． |
| 关键词: 多媒体，面向对象数据库，数据模型，概念模拟，对象代数． |
| DOI： |
| 分类号: |
| 基金项目:本文研究得到国家自然科学基金重点项目资助. |
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| AN OBJECT—ORIENTED MULTIMEDIA CoNCEPTUAL MoDEL |
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Zhang Xia,Liu Jiren,Li Huatian
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| Abstract: |
| This paper presents a formal conceptual model for multimedia objects，name-ly，OMCOM(object—oriented multimedia conceptual model)．First，the particularities of the multimedia data modelling are analyzed，the inadequacies of existing multimedia data models are discussed．As a result，the idea is proposed that multimedia data modelling should be divided into two layers：one is the conceptual layer which models the contents and structures of multimedia objects，and the other is the presentation layer which models their presentations including their temporal and spatial relationships．OMCOM is the roodel used to implement the conceptual modelling．Secondly．the formal definitions of the elements in OMCOM are given according to the requirements of multimedia conceptual mod-elling．Finally，object algebra is defined，which is based on the lattice property of OM-COM instances．Object algebra is the system of operations over multimedia objects on the conceptual layer．The formal definitions of object algebra operators and expressions are given． |
| Key words: Multimedia,object—oriented database,data model,conceptual modelling,object algebra． |
