Abstract: The current research progresses and the existing problems of description logic DL， especially the insufficiency of using dynamic description logic DDL to act as logical foundation for the semantic Web， are analyzed. According to the characteristics and requirement of the semantic Web， a kind of new description logic， i．e．， fuzzy dynamic description logic FDDL， is presented. The syntax and semantics of FDDL are given. The reasoning mechanism of FDDL is studied. The FDDL provides more reasonable logic foundation for the semantic Web， and overcomes the insufficiency of using dynamic description logic DDL to act as logical foundation for the semantic Web．

Key words: dynamic description logic, fuzzy description logic, fuzzy dynamic description logic, semantic Web

摘要： 分析了目前描述逻辑DL的研究现状和存在的问题，特别是动态描述逻辑DDL作为语义Web逻辑基础所存在的问题。针对语义Web需要处理模糊和不精确知识的特点和需求，对DDL进行了模糊化扩充，提出了一种新的描述逻辑，即模糊动态描述逻辑FDDL。给出了FDDL的语法和语义，研究了FDDL的推理机制。与动态描述逻辑DDL相比，该FDDL可以为语义Web提供更为合理的逻辑基础，弥补了DDL作为语义Web逻辑基础的不足。

关键词: 动态描述逻辑, 模糊描述逻辑, 模糊动态描述逻辑, 语义Web