中文摘要：

地质时间是地球科学基础研究的重要内容,在异构数据集和文献中有多种描述方式,其语义异构问题成为影响数据共享与集成的瓶颈之一。本体（Ontology）是共享概念模型的明确的形式化规范说明,可以用来描述数据的语义信息,近年来,被广泛应用于解决语义异构问题。本文以地质时间作为研究对象,分析了地质时间这一特定领域蕴含的基本概念、属性和关系,构建了地质时间的领域本体和OWL的编码表达,并以关系型数据库为例,阐述了地质时间本体的语义映射和翻译机制。该机制能够有效地在W eb环境下为传统数据检索增强语义表达能力,识别地质时间不同表达方式中的等价、包含等隐含关系,实现语义的数据检索。该方法也适用于地球科学其他领域本体的构建和语义翻译,为解决地球科学数据的语义异构问题提供了思路。

英文摘要：

Geologic time is fundamental information for earth science problems.It is commonly described in diverse resources in different styles and formats.Traditional information searching method couldn＇t extract implicit meaning and relationships from terms in these datasets.Ontology is defined as an explicit formal specification of a shared conceptualization which can play a central role in semantic heterogeneity problem and lead to semantic integration of data across several disciplines of earth sciences.In this paper,we adopt ontology approach to resolve geologic time semantic heterogeneous problems among earth science relational databases.We firstly construct geologic time ontology and then encode it in OWL.This owl provides an organizational structure for classifying geologic time data that can be discovered by both human beings and computers.Based on this ontology,a semantic mapping mechanism for querying among heterogeneous earth science databases is addressed.We describe this mechanism which generates candidate matches from targeted geologic databases and specific ontology manually,and then creates data mapping and translate data based on matches automatically.We apply this mechanism to a four-layer hierarchical system based on WebGIS.A search example is given at the end of the paper.The result shows that this mechanism can discover matches with high accuracy and provide one simple query interface for heterogeneous databases.It resolves both syntactic and semantic heterogeneity and allowing integration of multiple distributed databases.