Motivation
    
      - In Grid computing (particularly infrastructure)
	
	  - Modeling stateful Web service instances (with identity)
 
	  - Certain services have complex state
	    
	      - Dozens (perhaps many dozens) of state elements
 
	    
	   
	  - Many of these state elements need to be publicly
	    accessible
	    
	      - get, set, query, subscribe for state change notification
 
	    
	   
	
       
      - These motivations are shared in other systems management
	contexts that may use Web services