数字地球与数字城市的关键技术－语义网和OWL简介.ppt

数字地球与数字城市的关键技术－语义网和OWL简介 《数字地球与数字城市》讲义之九 张雪虎 北京大学遥感与GIS研究所 2005年11月09日 xuehu@ 概述 语义网简介 OWL简介 实例演示（Protégé OWL ） 小结 语义网（Semantic Web） Tim Berners-Lee 推动的互联网2.0版 全面应用元数据技术（标识所有的东西） 而且是机器可以理解的“元数据” 本体技术是实现语义网的核心 注意：不要和语义网络（Semantic Network）混淆 Tim Berners-Lee讲故事 The entertainment system was belting out the Beatles We Can Work It Out when the phone rang. When Pete answered, his phone turned the sound down by sending a message to all the other local devices that had a volume control. His sister, Lucy, was on the line from the doctors office: Mom needs to see a specialist and then has to have a series of physical therapy sessions. Biweekly or something. Im going to have my agent set up the appointments. Pete immediately agreed to share the chauffeuring. Tim Berners-Lee讲故事 At the doctors office, Lucy instructed her Semantic Web agent through her handheld Web browser. The agent promptly retrieved information about Moms prescribed treatment from the doctors agent, looked up several lists of providers, and checked for the ones in-plan for Moms insurance within a 20-mile radius of her home and with a rating of excellent or very good on trusted rating services. It then began trying to find a match between available appointment times (supplied by the agents of individual providers through their Web sites) and Petes and Lucys busy schedules. （The emphasized keywords indicate terms whose semantics, or meaning, were defined for the agent through the Semantic Web.） Tim Berners-Lee讲故事 In a few minutes the agent presented them with a plan. Pete didnt like it—University Hospital was all the way across town from Moms place, and hed be driving back in the middle of rush hour. He set his own agent to redo the search with stricter preferences about location and time. Lucys agent, having complete trust in Petes agent in the context of the present task, automatically assisted by supplying access certificates and shortcuts to the data it had already sorted through. Tim Berners-Lee讲故事 Almo