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Common specification of radiotherapeutical apparatuses and their appearance in departments of radiation therapy in the Czech republic
NOVÁK, Michal
From the first contact of patient with simulator to therapeutic application of radiation is the radiotherapy in direct contact with devices. The radiotherapeutical units are irreplaceable because the radiation therapy is impossible without these. The process of radiotherapy became more difficult with production of modern devices, using new techniques of irradiation, using new accesories, aids and especially with development of computer technology. This fact enabled approximation to the exacting requirements of modern radiotherapy. Today is the spectrum of radiotherapeutical units stabilize on several types which include most of clinical demands. These are linear accelerators, cobalt and cesium isotopic units, therapeutic X-ray devices and the automatic afterloading systems for brachytherapy. Today is the attention paid to expansion of technical abilities of existing units rather than to searching of new types of radiation sources. Using of unconventional sources of radiation, especially the neutron sources and accelerators of heavy parcticles, is exception. The subject of this bachelor essay is adumbrate meaning of devices in radiation therapy. Essay provide list of the most frequently devices which used for therapeutic application of ionizing radiation. These therapeutic units are generally specified in essay and there are provided important informations about incident of radiothe-rapeutical units at departments of radiotherapy in the Czech Republic.
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Vylešpení modelu dynamického rozhodování pomocí metody "Iteration spread in time"
Divišová, L. ; Zeman, Jan
In the present work we study the problem of ¯nding the best de- cision based on our previous experience with the system. To solve this task, we use the dynamic programming and its approximations. In the work we summarize the theory needed for usage of the dynamic programming and we deal with its application on futures dealing trying to ¯nd best strategy, id est a sequence of decisions, maximizing our gain or minimizing the loss function. We introduce notion "Bellman function", explain why the approximation of this function is needed, demonstrate one of already tested approximation methods together with its results and we try to propose a method that would lead to the best approximation in suitable time and with available computation aids.
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Metody s proměnnou metrikou s omezenou pamětí, založené na invariantních maticích
Vlček, Jan ; Lukšan, Ladislav
A new class of limited-memory variable metric methods for unconstrained minimization is described. Approximations of inverses of Hessian matrices are based on matrices which are invariant with respect to a linear transformation. As these matrices are singular, they are adjusted for a computation of direction vectors. The methods have the quadratic termination property, which means that they will find a minimum of a strict quadratic function with an exact choice of a step-length after a finite number of steps. Numerical experiments show the efficiency of this method.
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Approximate calculation of eigen-values of linear viscously damped system with passive damping element
Hračov, Stanislav
The paper presents an approximative method for eigen-solution of non-classically damped linear system representing classically damped structure equipped with passive damping element (viscous damper). The proposed procedure avoids using a numerically demanding state-space approach. It operates in the original dimension of the problem and utilizes the real eigen-modes for its further size reduction. The method is based on the dividing of the damping matrix to classical and non-classical part and the application of the perturbation strategy. The accuracy of the procedure is demonstrated by considering numerical examples.
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Methods of real root approximation using the Maple software
KOTREJCHOVÁ, Jana
The thesis offers the reader a general view of Maple 9.5 tools with orientation to methods of approximation in real roots of polynomial functions. Beside built-in functions and Maplets, autographically programmed Maplets will be shown and used. The work can be used as a suitable device for understanding problems, teaching and also as an application in problem solving exercises.
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