Seite - 115 - in Adaptive and Intelligent Temperature Control of Microwave Heating Systems with Multiple Sources

4.2. IntelligentControl Therelationshipbetweenthestateandstate-actionvaluefunctionsare representedbythe followingtwoequations [Bar98] Vpi(s) = ∑ u pi(u|s)Qpi(s,u), (4.36) Qpi(s,u) = ∑ s′ Pu(s,s ′,r)[r(s,u,s′)+γVpi(s′)], (4.37) wherepi(u|s) is the probability of taking actionu in the state sunder thecontrolpolicypi. Combiningthese twoequations together, there is theso-calledBellmanequationgivenas [Bar98] Vpi(s) = ∑ u pi(u|s) ∑ s′ Pu(s,s ′,r)[r(s,u,s′)+γVpi(s′)]. (4.38) Definingtheoptimalstateandstate-actionvalue functionsas V∗(s) = max pi Vpi(s), (4.39) Q∗(s,u) = max pi Qpi(s,u), (4.40) respectively, the Bellman optimality equations are expressed as [Bar98] V∗(s) = max u E [ R(k+1)+γV∗(S(k+1)) ∣∣S(k) =s,U(k) =u] = max u ∑ u pi(u|s) ∑ s′ Pu(s,s ′,r)[r(s,u,s′)+γV∗(s′)], (4.41) Q∗(s,u) =E [ R(k+1)+γmax u′ Q∗(s,u′) ∣∣S(k) =s,U(k) =u] = ∑ s′ Pu(s,s ′,r) [ r(s,u,s′)+γmax u′ Q∗(s′,u′) ] . (4.42) The Bellman optimality equation is the foundation of RLC as well as theconventionaloptimalcontrol [LV09]. It reveals therelationshipbe- tweenthecurrentstate (orstate-actionpair)anditssuccessorstate (or state-actionpair),whichtransferstheprocessofdeterminingthelong- termoptimalcontrol sequence intoaone-stepsearchofequation 4.41 115