rule-based expert systems基于规则的专家系统

《rule-based expert systems基于规则的专家系统》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、1Rule-basedexpertsystemsThemostpopularchoiceforbuildingknowledge-basedsystems:rule-basedexpertsystems.2Introduction,orwhatisknowledge?Inthe1970s,itwasfinallyacceptedthattomakeamachinesolveanintellectualproblemonehadtoknowthesolution.Inotherwords,onehastohavekno

2、wledge,'know-how',insomespecificdomain.3Whatisknowledge?Knowledgeisatheoreticalorpracticalunderstandingofasubjectoradomain.Knowledgeisalsothesumofwhatiscurrentlyknown,andapparentlyknowledgeispower.4Thosewhopossessknowledgearecalledexperts.Theyarethemostpowerful

3、andimportantpeopleintheirorganisations.Anysuccessfulcompanyhasatleastafewfirst-classexpertsanditcannotremaininbusinesswithoutthem.5Whoisgenerallyacknowledgedasanexpert?Anyonecanbeconsideredadomainexpertifheorshehasdeepknowledge(ofbothfactsandrules)andstrongprac

4、ticalexperienceinaparticulardomain.Theareaofthedomainmaybelimited.6Expertsinelectricalmachinesmayhaveonlygeneralknowledgeabouttransformers,whileexpertsinlifeinsurancemarketingmighthavelimitedunderstandingofarealestateinsurancepolicy.Ingeneral,anexpertisaskilful

5、personwhocandothingsotherpeoplecannot.7Howdoexpertsthink?Thehumanmentalprocessisinternal,anditistoocomplextoberepresentedasinalgorithm.However,mostexpertsarecapableofexpressingtheirknowledgeintheformofrulesforproblemsolving.8Considerasimpleexample.Imagine,youme

6、etanalien!Hewantstocrossaroad.Canyouhelphim?Youareanexpertincrossingroads-you'vebeenonthisjobforseveralyears.Thusyouareabletoteachthealien.Howwouldyoudothis?9Youexplaintothealienthathecancrosstheroadsafelywhenthetrafficlightisgreen,andhemuststopwhenthetrafficli

7、ghtisred10Thesearethebasicrules.Yourknowledgecanbeformulatedasthefollowingsimplestatements:IFthe'trafficlight'isgreenTHENtheactionisgoIFthe'trafficlight'isredTHENtheactionisstop11ThesestatementsrepresentedintheIF-THENformarecalledproductionrulesorjustrules.Thet

8、erm'rule'inAI,whichisthemostcommonlyusedtypeofknowledgerepresentation,canbedefinedasanIF-THENstructurethatrelatesgiveninformationorfactsintheIFparttosomeactionintheTHENpart.