Proposes a new method to handle policies in Resource Management of Workflow Systems

resource management in workflow consists of:

    	resource  modeling
    	effective  allocation  upon  users’  requests

enforce policies by query rewriting

    	 A  resource  query  is  sent  to  the policy  manager  where  
    	 relevant  policies  are  first  retrieved,  
    	 then  either  additional selection  criteria  
    	 are  appended  to  the  initial  query  (in  the  case  of  requirement policies) 
    	 or a new query is returned (in the case of substitution policies)
    	 [a sql-like query]
    	 [however, this way implies the resource model is known in advance.]

types of policies:

    	qualification
    		states a type of resources is qualified to do a type of activities
    	requirement
    		states that if a resource is chosen to carry out an activity with
    		specified  characteristics,  the  resource  must  satisfy  certain  conditions
    	substitution
    		states  that  the  substituting  resource  can  replace  the  substituted  resource