In DDL, a formal meaning is assigned to the interaction be-tween services and the environment. Thus DDL bridges the gap between the static reasoningon content and the dynamic reasoning on services in an inherent, consistent and seamless way.

• 用逻辑的方法明确地描述了环境与服务之间的交互的内涵语义,填补基于语义内容的推理和基于服务的过程推理之间的鸿沟,达到两者内在的、一致的、无缝的结合。