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Wyszukujesz frazę "Ledzewicz, U." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Singular controls and chattering arcs in optimal control problems arising in biomedicine
Autorzy:
Ledzewicz, U.
Schattler, H.
Powiązania:
https://bibliotekanauki.pl/articles/970774.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal control
singular controls
biomedical models
anti-angiogenesis
Opis:
We consider an optimal control problem of the Mayer-type for a single-input, control affine, nonlinear system in small dimension. In this paper, we analyze effects that a modeling extension has on the optimality of singular controls when the control is replaced with the output of a first-order, time-invariant linear system driven by a new control. This analysis is motivated by an optimal control problem for a novel cancer treatment method, tumor anti-angiogenesis, when such a linear differential equation, which represents the pharmacokinetics of the therapeutic agent, is added to the model. We show that formulas that define a singular control of order 1 and its associated singular arc carry over verbatim under this model extension, albeit with a different interpretation. But the intrinsic order of the singular control increases to 2. As a, consequence, optimal concatenation sequences with the singular control change and the possibility of optimal chattering arcs arises.
Źródło:
Control and Cybernetics; 2009, 38, 4B; 1501-1523
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite dimensional models of drug resistant and phase specific cancer chemotherapy
Autorzy:
Ledzewicz, U.
Schättler, H.
Świerniak, A.
Powiązania:
https://bibliotekanauki.pl/articles/333055.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
chemioterapia
odporność na leki
specyfika fazy
bio-modelowanie matematyczne
optymalna kontrola
chemotherapy
drug resistance
phase specificity
biomathematical modelling
optimal control
Opis:
The problem of modelling drug resistance and phase specificity of cancer chemotherapy using finite dimensional models were considered. We formulate optimal control problems arising in protocol design for such models and discuss research issues resulting from these formulations.
Źródło:
Journal of Medical Informatics & Technologies; 2004, 8; IP5-14
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal Control for a Class of Compartmental Models in Cancer Chemotherapy
Autorzy:
Świerniak, A.
Ledzewicz, U.
Schättler, H.
Powiązania:
https://bibliotekanauki.pl/articles/908158.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
medycyna
matematyka
compartmental models
cancer chemotherapy
optimal control
necessary and sufficient conditions for optimality
Opis:
We consider a general class of mathematical models P for cancer chemotherapy described as optimal control problems over a fixed horizon with dynamics given by a bilinear system and an objective which is linear in the control. Several two- and three-compartment models considered earlier fall into this class. While a killing agent which is active during cell division constitutes the only control considered in the two-compartment model, Model A, also two three-compartment models, Models B and C, are analyzed, which consider a blocking agent and a recruiting agent, respectively. In Model B a blocking agent which slows down cell growth during the synthesis allowing in consequence the synchronization of the neoplastic population is added. In Model C the recruitment of dormant cells from the quiescent phase to enable their efficient treatment by a cytotoxic drug is included. In all models the cumulative effect of the killing agent is used to model the negative effect of the treatment on healthy cells. For each model it is shown that singular controls are not optimal. Then sharp necessary and sufficient optimality conditions for bang-bang controls are given for the general class of models P and illustrated with numerical examples.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2003, 13, 3; 357-368
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sufficient conditions for optimality for a mathematical model of drug treatment with pharmacodynamics
Autorzy:
Leszczynski, M.
Ratajczyk, E.
Ledzewicz, U.
Schättler, H.
Powiązania:
https://bibliotekanauki.pl/articles/255130.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
optimal control
sufficient conditions for optimality
method of characteristics
pharmacodynamic model
Opis:
We consider an optimal control problem for a general mathematical model of drug treatment with a single agent. The control represents the concentration of the agent and its effect (pharmacodynamics) is modelled by a Hill function (i.e., Michaelis-Menten type kinetics). The aim is to minimize a cost functional consisting of a weighted average related to the state of the system (both at the end and during a fixed therapy horizon) and to the total amount of drugs given. The latter is an indirect measure for the side effects of treatment. It is shown that optimal controls are continuous functions of time that change between full or no dose segments with connecting pieces that take values in the interior of the control set. Sufficient conditions for the strong local optimality of an extremal controlled trajectory in terms of the existence of a solution to a piecewise defined Riccati differential equation are given.
Źródło:
Opuscula Mathematica; 2017, 37, 3; 403-419
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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