319 research outputs found

    Numerical investigation of novel microwave applicators based on zero-order mode resonance for hyperthermia treatment of cancer

    Get PDF
    This paper characterizes three novel microwave applicators based on zero-order mode resonators for use in hyperthermia treatment of cancer. The radiation patterns are studied with numerical simulations in muscle tissue-equivalent model at 434 MHz. The relative performance of the applicators is compared in terms of reflection coefficient, current distribution, power deposition (SAR) pattern, effective field size in 2D and 3D tissue volumes, and penetration depth. One particular configuration generated the most uniform SAR pattern, with 25% SAR covering 84 % of the treatment volume extending to 1 cm depth under the aperture, while remaining above 58% coverage as deep as 3 cm under the aperture. Recommendations are made to further optimize this structure

    Novel Applicators for Local Microwave Hyperthermia Based on Zeroth-Order Mode Resonator Metamaterial

    Get PDF
    It is demonstrated that a theory of zero-order mode resonator (ZOR) metamaterial (MTM) structure can be used for the development of a novel class of applicators for microwave thermotherapy, for example, for hyperthermia in cancer treatment or for physiotherapy. The main idea of creating such an applicator is to generate and radiate a plane electromagnetic (EM) wave into the treated biological tissue, at least in a certain extent. The main aim of this paper is to investigate whether an EM wave generated by ZOR MTM structure and emitted into the biological tissue can produce a homogeneous SAR distribution in the planes parallel to the applicator aperture and achieve a penetration depth approaching the theoretical limit represented by SAR distribution and penetration depth of an ideal EM plane wave. EM field distribution inside a virtual phantom of the treated region generated by the applicator that is based on the proposed ZOR MTM principle is investigated using a well-proven full-wave commercial simulation tool. The proposed applicator type shows both a low unwanted leaked electromagnetic field and a fairly homogeneous electric field in its aperture as well as in the virtual phantom of the treated region

    Cooperation of active steering control of wheelsets with subsystems of an autonomous urban rail vehicle

    Get PDF
    The paper presents the motivations for the application of actively controlled elements in the running gear of a rail vehicle and the challenges that need to be addressed before deploying vehicles with actively controlled elements in real operation. Furthermore, the paper presents the design of an active element concept and its control for steering the axles of an urban rail vehicle to improve the vehicle’s passage through small radius curves. The design takes into account the fundamental issues of cost and safety of the application of active elements, which are addressed in the presented control design by using data from autonomous driving subsystems such as the environmental database or the anti-collision system

    Novel Microwave Applicators Based on Zero-Order Mode Resonance for Hyperthermia Treatment of Cancer

    Get PDF
    In this paper, three novel microwave applicator prototypes based on zero-order mode resonators are proposed for use in hyperthermia treatment of cancer. The ability of all three applicators to homogenously irradiate muscle tissue-equivalent phantoms is demonstrated with results of numerical simulations, and relative performance of the applicators is compared

    Prospective Applications of Microwaves in Medicine

    Get PDF

    Microwave Tomography System for Methodical Testing of Human Brain Stroke Detection Approaches

    Get PDF
    In this work, a prototype of a laboratory microwave imaging system suitable to methodically test the ability to image, detect, and classify human brain strokes using microwave technology is presented. It consists of an antenna array holder equipped with ten newly developed slot bowtie antennas, a 2.5 D reconfigurable and replaceable human head phantom, stroke phantoms, and related measuring technology and software. This prototype was designed to allow measurement of a complete S-matrix of the antenna array. The reconfigurable and replaceable phantom has currently 23 different predefined positions for stroke phantom placement. This setting allows repeated measurements for the stroke phantoms of different types, sizes/shapes, and at different positions. It is therefore suitable for large-scale measurements with high variability of measured data for stroke detection and classification based on machine learning methods. In order to verify the functionality of the measuring system, S-parameters were measured for a hemorrhagic phantom sequentially placed on 23 different positions and distributions of dielectric parameters were reconstructed using the Gauss-Newton iterative reconstruction algorithm. The results correlate well with the actual position of the stroke phantom and its type

    A Controlled Searching of Game Trees

    Get PDF
    Title: A Controlled Searching of Game Trees Author: Jan Vrba Department: Department of Theoretical Computer Science and Mathematical Logic Supervisor: RNDr. Jan Hric Abstract: Monte-Carlo Tree Search is a search algorithm based on random Monte- Carlo playouts. Since it was first introduced in 2006, it has been successfully used in several areas. Most notably for the game Go. MCTS is intended mainly for problems with too large a state space to be fully explored in reasonable time. Working with a large state space and the fact that when evaluating a node, it first explores all possible moves leads to large memory complexity. This work explores options a user can use to regulate memory complexity based on the results of previous Monte-Carlo playouts. Keywords: MCTS, UCT, BMCTS, RAVENázev práce: Řízení prohledávání stromů hry Autor: Jan Vrba Katedra / Ústav: Katedra teoretické informatiky a matematické logiky Vedoucí bakalářské práce: RNDr. Jan Hric Abstrakt: Monte-Carlo Tree Search je metodou prohledávání herního stromu na základě náhodných Monte-Carlo sehrávek. Od doby, kdy byla tato metoda poprvé představena v roce 2006, byla úspěšně použita v mnoha různých oblastech. Za zvláštní zmínku stojí její použití pro hru Go. MCTS je určeno především pro problémy, které mají příliš velký stavový prostor, aby šel prohledat v rozumném čase. Práce s velkým stavovým prostorem a skutečnost, že metoda při rozvíjení vrcholu každý možný tah nejdříve jednou vyzkouší vede k velkým paměťovým nárokům. Tato práce se zabývá možnostmi, kterými může uživatel, v závislosti na provedených náhodných sehrávkách, regulovat paměťovou komplexitu. Klíčová slova: MCTS, UCT, BMCTS, RAVEKatedra teoretické informatiky a matematické logikyDepartment of Theoretical Computer Science and Mathematical LogicMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

    Virtual Simulation Model of Automatic Transmission

    Get PDF
    Bakalářská práce pojednává o vytvoření virtuálního simulačního modelu automatické převodovky s využitím programů CANoe a MATLAB/Simulink. Cílem je vytvořit simulační model automatické převodovky na základě analýzy AUDI SSP 283 a 284, které se zabývají 6-stupňovou automatickou převodovkou 09E od výrobce ZF a ověřit jeho funkčnost pomocí testovacích scénářů. Vytvořený model byl implementován do simulačního modelu vozidla AEScar. V práci jsou popsány základy teorie automatických převodovek, použité programy a komunikační protokoly. Dále je v práci podrobně popsán vytvořený simulační model a jeho testování. Výsledky jsou porovnány s očekávanými hodnotami, diskutovány odchylky a možnosti vylepšení modelu.My bachelor thesis is about a virtual simulation model of automatic gearbox with use of applications CANoe and MATLAB/Simulink. The purpose of this thessis is to create an automatic transmission model based on AUDI SSP 283 and 284 analysis dealing with 6-speed automatic gearbox 09E manufactured by ZF and to verify its functionality with test scenarios. My model was implemented into the AEScar simulation model. My thesis consist of a description of automatic transmissions bases, used programs and communication protocols.There is also a detailed description of my model and of its testing. The results are compared to the expectations and there are mentioned possible improvements.430 - Katedra elektronikyvelmi dobř

    Analysis and Modelling of Medical Images

    Get PDF
    Hlavním cílem diplomové práce je rozbor technik hodnocení obličeje, kefalometrické hodnocení a metody, které jsou vhodné pro úpravu postavení čelistí a návrh metody pro úpravu čelistí. Zároveň je kladen důraz na prostudování používané metody java advance imaging, která slouží k zakřivení obrazu a měla by být schopna splnit cíle zadání. Tyto úpravy je možné provádět pomocí metody Warp. Výsledkem práce je aplikace, vytvořená v programovém jazyku JAVA, která demonstruje nejvhodnější metodu pro modifikaci obrazu. Tato metoda je WarpGrid. Aplikace byla vytvořena ve vývojovém prostředí eclipse. Pomocí této aplikace v závislosti na akci myši dochází k úpravám obrazu.The main objective of this thesis is an analysis of assessment techniques face, and cephalometric evaluation methods that are suitable for treatment of jaw position and design methods for treatment of jaw. At the same time the emphasis is on studying the methods,java advance imaging, which are used for the curvature of the image and should be able to meet the objectives of the assignment. These adjustments can be made using the Warp. Result of this work is an application developed in JAVA programming language, which demonstrates the best method for modifying the image. This method is WarpGrid. The application was made in the development environment eclipse. With this application, depending on the mouse action is possible to modify the image.
    corecore