Диссертация (1149840), страница 10
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Äëÿ ñóùåñòâîâàíèÿ óïðàâëåíèÿ, óäîâëåòâîðÿþùåãî íåîáõîäèìîìó óñëîâèþ, ñäåëàåì äîïîëíèòåëüíîå ïðåäïîëîæåíèå:lim x(τ ) = 0. Òàêèì îáðàçîì, ìû ïðåäïîëàãàåì, ÷òî ê ãàðàíòèðîâàííîìóτ →ωìîìåíòó îêîí÷àíèÿ ðàçðàáîòêè äîáûâàåòñÿ âåñü çàïàñ ðåñóðñà.Ãàìèëüòîíèàí ïðèìåò ñëåäóþùèé âèä:Hi =1 − Fi (τ )αi ln ui (x(τ ), τ )) − Λi ui (x(τ ), τ )1 − Fi (t)Çàïèøåì äèôôåðåíöèàëüíîå óðàâíåíèå äëÿ îïðåäåëåíèÿ ñîïðÿæ¼ííîé ïåðåìåííîé:Λ̇i = −∂Hi= 0,∂xîòêóäà çàêëþ÷àåì, ÷òî Λi (τ ) = Λ∗i = const,∀τ.Îïòèìàëüíîå óïðàâëåíèå ïîëó÷àåì èç óñëîâèÿ ïåðâîãî ïîðÿäêàu∗i (Λi , τ ) =αi 1 − Fi (τ ).Λ∗i 1 − Fi (t)∂Hi∂x=0:(4.6)78Äëÿ îïðåäåëåíèÿ çíà÷åíèÿ Λ∗i âîñïîëüçóåìñÿ ïðåäïîëîæåíèåì, ñäåëàííûìâûøå. Ïîäñòàâëÿåì óïðàâëåíèå (4.6) â óðàâíåíèå (4.4) è ïðèíèìàåì âî âíèìàíèå íà÷àëüíûå óñëîâèÿ è äîïîëíèòåëüíî lim x(τ ) = 0.τ →ωx=αiΛ∗iîòêóäà ïîëó÷àåìαiΛ∗i =xZω1 − Fi (τ )dτ,1 − Fi (t)tZω1 − Fi (τ )dτ.1 − Fi (t)tÏîäñòàâëÿåì ïîëó÷åííîå âûðàæåíèå â (4.6) è ïîëó÷àåì îïòèìàëüíîåóïðàâëåíèå êàê ôóíêöèþ íà÷àëüíûõ äàííûõ x:u∗i (x, τ ) = Rωx1 − Fi (τ ) .(4.7)1 − Fi (s) dstÈç óðàâíåíèÿ äèíàìèêè (4.4) ïîñëå ïîäñòàíîâêè (4.7) ïîëó÷àåìZτx(τ ) = x −txRω1 − Fi (s) dsx1 − Fi (θ) dθ = x −(I(t) − I(τ )),I(t)tãäå I(t) =Rωt(1 − Fi (s))ds.
Ïîñëå ïðåîáðàçîâàíèé ïîëó÷àåìx(τ ) = xI(τ ),I(t)τ ≥ t,(4.8)è ñîîòâåòñòâåííîx = x(τ )I(t).I(τ )Ïîäñòàâëÿåì ïîëó÷åííîå âûðàæåíèå â (4.7) è îêîí÷àòåëüíî ïîëó÷àåì îïòè-79ìàëüíîå óïðàâëåíèå â ôîðìå óïðàâëåíèÿ ñ îáðàòíîé ñâÿçüþ:u∗i (x(τ ), τ ) =x(τ )1 − Fi (τ ) .I(τ )(4.9)Çàìåòèì, ÷òî óïðàâëåíèå â âèäå (4.9) íå çàâèñèò îò íà÷àëüíîãî ìîìåíòà âðåìåíè t è íà÷àëüíîãî çàïàñà ðåñóðñà x.Ïåðåéä¼ì òåïåðü ê îïðåäåëåíèþ ôóíêöèè çíà÷åíèÿ Wi (t, x). ÔóíêöèÿWi (t, x) îïðåäåëÿåòñÿ êàê çíà÷åíèå ôóíêöèîíàëà (4.5) ïðè îïòèìàëüíîìóïðàâëåíèè (4.9).
Òàêèì îáðàçîì, èìååì:ZωWi (t, x) =!1 − Fi (τ )x(τ )αi ln1 − Fi (τ ) dτ.1 − Fi (t)I(τ )tÈñïîëüçóÿ ñîîòíîøåíèå (4.8), ïðîäîëæàåì ïðåîáðàçîâàíèåZωWi (t, x) =!1 − Fi (τ )xI(τ )αi ln1 − Fi (τ ) dτ =1 − Fi (t)I(t)I(τ )tI(t)x= αiln1 − Fi (t)I(t)αi+1 − Fi (t)Zω1 − Fi (τ ) ln 1 − Fi (τ ) dτ =t= Ci (t) ln(x) + Di (t),(4.10)ãäåCi (t) = αiDi (t) = −αiI(t);1 − Fi (t)(4.11)I(t)ln (I(t)) +1 − Fi (t)αi+1 − Fi (t)Zω1 − Fi (τ ) ln 1 − Fi (τ ) dτ. (4.12)tÏðèìåíèì äëÿ ðåøåíèÿ äàííîé çàäà÷è îïòèìàëüíîãî óïðàâëåíèÿ ïðèíöèï80äèíàìè÷åñêîãî ïðîãðàììèðîâàíèÿ. Óðàâíåíèå Áåëëìàíà (3.37) èìååò âèä:"#∂Wi (t, x)∂Wi (t, x)−+ Wi (t, x)λi (t) = max −ui+ αi ln(ui ) .ui∂t∂x∂W(t,x)iÎïòèìàëüíîå óïðàâëåíèå u∗i íàõîäèòñÿ êàê argmax −ui+ αi ln(ui ) ,∂xòî åñòü, èìååò âèäαiu∗i (x, t) =.∂Wi (t, x)/∂xÏåðåïèøåì óðàâíåíèå Áåëëìàíà:∂Wi (t, x)∂Wi (t, x)−+ Wi (t, x)λi (t) + αi (1 − ln αi ) + αi ln= 0.∂t∂x(4.13)Ïðåäïîëîæèì, ÷òî ôóíêöèÿ çíà÷åíèÿ èìååò âèä (4.10).
Ïîäñòàâëÿÿ ýòîò âèäâ óðàâíåíèå (4.13), ïîëó÷àåì:Ci (t)−Ċi (t) ln x− Ḋi (t)+ Ci (t) ln(x)+Di (t) λi (t)+αi (1−ln αi )+αi lnx!= 0.Ïîëó÷åííîå óðàâíåíèå ðàâíîñèëüíî ñëåäóþùåé ñèñòåìå äèôôåðåíöèàëüíûõóðàâíåíèé:−Ċi (t) + λi (t)Ci (t) − αi = 0;(4.14)−Ḋi (t) + λi (t)Di (t) + αi (1 − ln αi ) + αi ln Ci (t) = 0.(4.15)Ôóíêöèÿ çíà÷åíèÿ ïî îïðåäåëåíèþ óäîâëåòðîâÿåò ñëåäóþùåìó ñâîéñòâó(3.37): Wi (ω, x) = 0.
Ñëåäîâàòåëüíî, äëÿ ðåøåíèé ñèñòåìû (4.14-4.15) ñïðàâåäëèâû ãðàíè÷íûå óñëîâèÿ:lim Ci (t) = lim Di (t) = 0.t→ωt→ω(4.16)Íàõîäèì ðåøåíèå ëèíåéíîãî äèôôåðåíöèàëüíîãî óðàâíåíèÿ (4.14), óäîâëå-81òâîðÿþùåå óñëîâèþ (4.16)RtCi (t) = αi e 0λi (s)dsZωRτ− λi (s)dse0dτ.(4.17)tÎòìåòèì, ÷òî âûðàæåíèå (4.17) ñîâïàäàåò ñ ïîëó÷åííûì ðàíåå âûðàæåíèåì äëÿ Ci (t) ñ ïîìîùüþ ïðèíöèïà ìàêñèìóìà (4.11). ×òîáû ïîêàçàòü ýòî,äîñòàòî÷íî âîñïîëüçîâàòüñÿ ñîîòíîøåíèåì1 − Fi (t) = eRt− λi (s)ds0(4.18),êîòîðîå íåïîñðåäñòâåííî ñëåäóåò èç (3.30).Àíàëîãè÷íî ìîæíî ïîêàçàòü, ÷òî ôóíêöèÿ Di (t), çàäàííàÿ âûðàæåíèåì(4.12), óäîâëåòâîðÿåò óðàâíåíèþ (4.15) ñ ãðàíè÷íûìè óñëîâèÿìè (4.16).
Òàêèì îáðàçîì ïîêàçàíî, ÷òî ôóíêöèÿ çíà÷åíèÿ (4.10), ïîëó÷åííàÿ ñ ïîìîùüþïðèíöèïà ìàêñèìóìà, óäîâëåòâîðÿåò óðàâíåíèþ Áåëëìàíà äëÿ çàäà÷ îïòèìàëüíîãî óïðàâëåíèÿ ñî ñëó÷àéíîé ïðîäîëæèòåëüíîñòüþ (3.37).4.3.Ïîñòðîåíèå ðàâíîâåñèÿ ïî ÍýøóÏîñëå òîãî êàê íàéäåíî âûðàæåíèå äëÿ ôóíêöèé Áåëëìàíà (4.10) â çàäà÷àõ îïòèìàëüíîãî óïðàâëåíèÿ äëÿ êàæäîãî èãðîêà, ïåðåéä¼ì ê îïðåäåëåíèþâûèãðûøà èãðîêîâ â äèôôåðåíöèàëüíîé èãðå ñîâìåñòíîé ðàçðàáîòêè íåâîçîáíîâëÿåìîãî ðåñóðñà Γ(0, x0 ).
Âûèãðûø èãðîêà i (3.10) èìååò âèä:Ki (0, x0 , u1 , u2 ) =Zω αi ln ui (x(t), t) 1 − F (t) +0+ Ci (t) ln(x(t)) + Di (t) fj (t) 1 − Fi (t) dt;i, j ∈ {1, 2} (i 6= j),(4.19)82ãäå Ci (t), Di (t) ñîîòâåòñòâåííî èìåþò âèä (4.11) è (4.12), à F (t) ïðåäñòàâëÿåòñîáîé ôóíêöèþ ðàñïðåäåëåíèÿ ñëó÷àéíîé âåëè÷èíû ìîìåíòà âðåìåíè, âêîòîðûé ïåðâàÿ ïî î÷åðåäè ôèðìà ïðåêðàùàåò äîáû÷ó ðåñóðñà. Êàê óæåîòìå÷àëîñü â ïðåäûäóùåé ãëàâå, F (t) îïðåäåëÿåòñÿ ñîîòíîøåíèåì (3.7).Òàêèì îáðàçîì äèôôåðåíöèàëüíàÿ èãðà ñîâìåñòíîé ðàçðàáîòêè íåâîçîáíîâëÿåìîãî ðåñóðñà ïîëíîñòüþ îïðåäåëåíà: êàæäûé èãðîê ñòðåìèòñÿ ìàêñèìèçèðîâàòü ñâîé ôóíêöèîíàë âûèãðûøà (4.19), ïðè ýòîì äèíàìèêà èçìåíåíèÿ çàïàñà ðåñóðñà âûðàæàåòñÿ äèôôåðåíöèàëüíûì óðàâíåíèåì (4.1) ñ íà÷àëüíûì çíà÷åíèåì çàïàñà (4.2).Äëÿ ïîñòðîåíèÿ ñîñòîÿòåëüíîãî ïîçèöèîííîãî ðàâíîâåñèÿ ïî Íýøó{u∗i (x, t), i = 1, 2} âîñïîëüçóåìñÿ òåîðåìîé 3.4.
Ñèñòåìà óðàâíåíèé â ÷àñòíûõïðîèçâîäíûõ îòíîñèòåëüíîé ôóíêöèé Vi (t, x), i ∈ {1, 2} èìååò ñëåäóþùèé âèä"∂Vi (t, x)∂Vi (t, x)+ Vi (t, x) [λi (t) + λj (t)] = max αi ln(ui ) −(ui + u∗j (x, t))+ui∂t∂x#∂Vi (t, x) ∗(ui (x, t) + u∗j (x, t))++ Ci (t) ln(x) + Di (t) λj (t) = αi ln u∗i (x, t) −∂x+ Ci (t) ln(x) + Di (t) λj (t); i, j ∈ {1, 2} (i 6= j).(4.20)−Äëÿ íàõîæäåíèÿ ðàâíîâåñíûõ ñòðàòåãèé â ÿâíîì âèäå ïî àíàëîãèè ñ çàäà÷åé îïòèìàëüíîãî óïðàâëåíèÿ ïðåäïîëîæèì ñëåäóþùèé âèä ðåøåíèÿ (4.20):Vi (t, x) = Ai (t) ln x + Bi (t),i ∈ {1, 2},(4.21)ãäå Ai (t) è Bi (t) íåèçâåñòíûå ôóíêöèè âðåìåíè t.Ïî óñëîâèþ òåîðåìû 3.4: lim Vi (t, x) = 0.
Èñõîäÿ èç ïðåäñòàâëåíèÿ (4.21),t→ωèìååì ñëåäóþùèå ãðàíè÷íûå óñëîâèÿ:lim Ai (t) = 0,t→ωlim Bi (t) = 0.t→ω(4.22)83Çàïèøåì âûðàæåíèÿ äëÿ ÷àñòíûõ ïðîèçâîäíûõ ôóíêöèè (4.21), âõîäÿùèõâ óðàâíåíèå (4.20):∂Vi (t, x)= Ȧi (t) ln x + Ḃi (t),∂t∂Vi (t, x) Ai (t)=.∂xxÌàêñèìèçèðóÿ ïðàâóþ ÷àñòü (4.20), íàõîäèìαi∂Vi (t, x)αi x∗−=0⇐⇒u(x,t)=.iu∗i (x, t)∂xAi (t)(4.23)∂Wi (t, x) ∂Wi (t, x)èâ (4.20), ïîëó÷àåì∂t∂täèôôåðåíöèàëüíîå óðàâíåíèå, êîòîðîå ñïðàâåäëèâî ïðè âñåõ çíà÷åíèÿõ çàÏîäñòàâëÿÿ âûðàæåíèÿ äëÿ u∗i ,ïàñà ðåñóðñà x:−Ȧi (t) ln x − Ḃi (t) + Ai (t) ln x + Bi (t) λi (t) + λj (t) =αi xAi (t) αi xαj x= αi ln+ Ci (t) ln x + Di (t) λj (t) −+.Ai (t)xAi (t) Aj (t)(4.24)Ïðèðàâíÿâ êîýôôèöèåíòû ïðè ln x èç ïðàâîé è ëåâîé ÷àñòåé (4.24), à òàêæå ñâîáîäíûå ÷ëåíû, èìååì ñëåäóþùóþ ñèñòåìó îáûêíîâåííûõ äèôôåðåíöèàëüíûõ óðàâíåíèé äëÿ îïðåäåëåíèÿ íåèçâåñòíûõ ôóíêöèé âðåìåíè Ai (t) èBi (t):−Ȧi (t) + Ai (t) [λi (t) + λj (t)] − αi − Ci (t)λj (t) = 0,(4.25)−Ḃi (t) + Bi (t) [λi (t) + λj (t)] + αi ln Ai (t) − Di (t)λj (t)++αi (1 − ln αi ) + αjAi (t)= 0.Aj (t)(4.26)Îïðåäåëÿåì íåèçâåñòíûå ôóíêöèè Ai (t) è Bi (t), ðåøàÿ ñèñòåìó (4.25)-(4.26)ñ ó÷¼òîì ãðàíè÷íûõ óñëîâèé (4.22).Óòâåðæäåíèå 4.1.
Ñòðåòåãèè, ñîñòàâëÿþùèå ñîñòîÿòåëüíîå ïîçèöèîí-84íîå ðàâíîâåñèå ïî Íýøó, èìåþò ñëåäóþùèé âèäα1−F(t)xiu∗i (t, x) = Rω ,αi 1 − F (τ ) + Ci (τ )fj (τ ) 1 − Fi (τ ) dτ(4.27)tãäåi, j ∈ {1, 2} (i 6= j).Äîêàçàòåëüñòâî. Äëÿ îïðåäåëåíèÿ ðàâíîâåñíîé ñòðàòåãèè ìîæíî îáîé-òèñü áåç íàõîæäåíèÿ ôóíêöèè Bi (t), òàê êàê îíà íå ïðèñóòñòâóåò â âûðàæåíèè (4.23) äëÿ îïðåäåëåíèÿ u∗i . Ðàññìîòðèì çàäà÷ó Êîøè äëÿ íàõîæäåíèÿôóíêöèè Ai (t):Ȧi (t) − λi (t) + λj (t) Ai (t) = −αi − Ci (t)λj (t).lim Ai (t) = 0.t→ωÎáùåå ðåøåíèå äàííîãî äèôôåðåíöèàëüíîãî óðàâíåíèÿ, çàäàåòñÿ ôîðìóëîéRtAi (t) = e(λi (τ )+λj (τ ))dτ0ZC−t − R τ (λ (s)+λ (s))dsjαi + Ci (τ )λj (τ ) e 0 idτ.0Ïðèìåíÿÿ óñëîâèÿ (4.22), îïðåäåëèì êîíñòàíòó CZω Rταi + Ci (τ )λj (τ ) e− 0 (λi (s)+λj (s))ds dτ,C=0÷òî ïðèâîäèò ê ðåøåíèþ ωZRt − R τ (λ (s)+λ (s))ds(λi (τ )+λj (τ ))dτ j0Ai (t) = eαi + Ci (τ )λj (τ ) e 0 idτ .(4.28)tÇàìåòèì, ÷òî èç âûðàæåíèÿ äëÿ ôóíêöèè ðàñïðåäåëåíèÿ ìèíèìóìà ìîìåíòîâîêîí÷àíèÿ (3.7) è ôîðìóëû (4.18) íåïîñðåäñòâåííî ñëåäóåò ñîîòíîøåíèå1 − F (t) = e−Rt0(λi (τ )+λj (τ ))dτ.(4.29)85Ïðèìåíÿÿ (4.29) ê ðåøåíèþ (4.30), ïîëó÷àåì èòîãîâîå ïðåäñòàâëåíèå ôóíêöèè Ai (t)Ai (t) =11 − F (t) ωZ αi 1 − F (τ ) + Ci (τ )fj (τ ) 1 − Fi (τ ) dτ .(4.30)tÎêîí÷àòåëüíî äëÿ ðàâíîâåñíîé ñòðàòåãèè i-ãî èãðîêà íàõîäèìα1−F(t)xαxiiu∗i (t, x) == Rω .Ai (t)αi 1 − F (τ ) + Ci (τ )fj (τ ) 1 − Fi (τ ) dτtÂûðàæåíèå äëÿ ðàâíîâåñíîé ñòðàòåãèè (4.27) ïîêàçûâàåò, ÷òî, äåéñòâóÿîïòèìàëüíî, êàæäûé èãðîê äîëæåí ó÷èòûâàòü íå òîëüêî èíôîðìàöèþ î ðàñïðåäåëåíèè ñâîåãî ìîìåíòà âûõîäà èç èãðû, íî è èíôîðìàöèþ î ìîìåíòåîêîí÷àíèÿ èãðû äëÿ äðóãîãî èãðîêà.Óòâåðæäåíèå 4.2.
Ôóíêöèÿ çíà÷åíèÿ èãðîêà i ∈ {1, 2} (âûèãðûø â ñèòó-àöèè ðàâíîâåñèÿ ïî Íýøó) ðàâíàVi (t, x) = Ai (t) ln x + Bi (t).Çäåñüi, j ∈ {1, 2} (i 6= j). Ai (t) íàõîäèòñÿ ïî ôîðìóëå (4.30), à Bi (t)èìååò ñëåäóþùèé âèä:1Bi (t) =1 − F (t)Zω Qi (τ ) 1 − F (τ ) + Di (t)fj (t) 1 − Fi (τ ) dτ , (4.31)tãäåQi (t) = −αi ln Ai (t) − αi (1 − ln αi ) − αjAi (t).Aj (t)(4.32)86Äîêàçàòåëüñòâî. Ïðè ñäåëàííûõ îáîçíà÷åíèÿõ (4.32) óðàâíåíèå (4.26)ïðèìåò ñëåäóþùèé âèä:fj (t)Di (t)Ḃi (t) − λi (t) + λj (t) Bi (t) = −Qi (t) −.1 − Fj (t)(4.33)Ðåøàÿ ýòî óðàâíåíèå àíàëîãè÷íî (4.25), íàõîäèì ðåøåíèå, óäîâëåòâîðÿþùååóñëîâèþ (4.22). Ðåøåíèå èìååò âèä (4.31).Íåïîñðåäñòâåííîé ïîäñòàíîâêîé ìîæíî óáåäèòüñÿ, ÷òî ïîëó÷åííûå ôóíêöèè çíà÷åíèÿ Vi (t, x) ÿâëÿþòñÿ ðåøåíèÿìè ñèñòåìû (4.20).Òàêèì îáðàçîì, ìû îïðåäåëèëè ðàâíîâåñíûå ñòðàòåãèè (4.27) è íàøëèôóíêöèè Vi (t, x) â âèäå (4.21), ïîëó÷èâ â ÿâíîì âèäå ôóíêöèè (4.30), (4.31).4.4.Ýêñïîíåíöèàëüíîå ðàñïðåäåëåíèå ìîìåíòîâ îêîí÷àíèÿ ðàçðàáîòêèÐàññìîòðèì ñëó÷àé, êîãäà ìîìåíòû îêîí÷àíèÿ ðàçðàáîòêè íåâîçîáíîâëÿåìîãî ðåñóðñà äëÿ êàæäîãî èãðîêà èìåþò óñå÷¼ííîå ýêñïîíåíöèàëüíîå ðàñïðåäåëåíèå íà îòðåçêå [0, ω].Ôóíêöèè ðàñïðåäåëåíèÿ ìîìåíòîâ îêîí÷àíèÿ èìåþò ñëåäóþùèé âèä1 − e−λi tFi (t) =,1 − e−λi ωt ∈ [0, ω], i ∈ {1, 2}.(4.34)Ïî ôîðìóëå (3.7) ïîëó÷àåì ôóíêöèþ ðàñïðåäåëåíèÿ ìîìåíòà çàâåðøåíèÿðàçðàáîòêè ïåðâîé ïî î÷åðåäè ôèðìîé (ìîìåíò îêîí÷àíèÿ èãðû)e−λ1 t − e−λ1 ω e−λ2 t − e−λ2 ωF (t) = 1 −.1 − e−λ1 ω 1 − e−λ2 ωÍà ðèñóíêå 4.1 ïðåäñòàâëåí ãðàôèê ôóíêöèé ðàñïðåäåëåíèÿ ìîìåíòîâîêîí÷àíèÿ ðàçðàáîòêè ðåñóðñà.















