High Energy Density Plasma Diagnostics Using Neutron and Gamma Detectors
Klír, Daniel; Cikhardt, Jakub
2017 - anglický Deuterium Z-pinches are e cient sources of pulsed soft and hard x-rays, fast ions, and neutrons. Many phenomena related to an acceleration of ions and neutron production on the Z-pinches have not yet been explained. Detailed understanding of these phenomena could be multidisciplinary important. Therefore, these phenomena are investigated in joint Czech-Russian experiments on the terawatt class GIT-12 device with the generator output voltage of 600 kV and current at stagnation of about 3 MA. These experiments are interesting since by using the novel experimental load composed of the deuterium gas-pu with outer plasma shell, the neutron yields were signi cantly increased from the order of 1011 to the order of 1012. Such relatively high neutron yields were earlier observed on the devices with signi cantly higher current as the Saturn generator with the pulsed current of about 10 MA. At the same time, in our experiments, hydrogen ions with an energy above 38 MeV were detected. Such results are unique in experiments on the generator with the abovementioned maximum current and voltage. The work reported in this thesis is focused on the diagnostics of Z-pinch plasma by neutron detectors and interpretation of the experimental results. The precise neutron diagnostics is in our experiments necessary because the produced neutron pulses carry the information about the deuterons which produced them. In this thesis, the extensive neutron detection system is presented. This system is based on several principally independent methods: neutron bubble detectors, scintillation neutron time-of- ight diagnostics, neutron activation diagnostics with the moderator (silver activation counter), and fast neutron activation diagnostics with various energy threshold. This diagnostic system was used to evaluate neutron yields, energy spectrum, and neutron uences at di erent distances and directions. The in uence of non-dd neutrons on the experimental results is discussed. Plné texty jsou dostupné v digitálním repozitáři ČVUT. High Energy Density Plasma Diagnostics Using Neutron and Gamma Detectors

Deuterium Z-pinches are e cient sources of pulsed soft and hard x-rays, fast ions, and neutrons. Many phenomena related to an acceleration of ions and neutron production on the Z-pinches have not ...

Klír, Daniel; Cikhardt, Jakub
České vysoké učení technické v Praze, 2017

Methods for Verification and Validation of Automotive Distributed Systems
Novák, Jiří; Sobotka, Jan
2017 - anglický Stále narustající složitost automobilových elektronických systému vytvárí poptávku po vhodných validacních a testovacích metodách. Smerování automobilového prumyslu k plne autonomním vozidlum tento trend dále podporuje. Cílem práce je rozšírit množinu dostupných testovacích metod v nekolika oblastech. První takovou oblastí jsou mericí metody pro komunikacní sbernici FlexRay. V porovnání se staršími standardy CAN a LIN je radic této sbernice konfigurován mnohem vetším množstvím parametru. Pro zajištení správné funkce systému je nutné overit, že aktuální hodnoty techto parametru odpovídají hodnotám požadovaným. Tento úkol vyžaduje návrh mericích metod schopných identifikovat skutecné hodnoty parametru. Další oblastí vyžadující doplnení stávajících testovací možností je integracní testování automobilové elektroniky. S rostoucím poctem elektronických rídicích jednotek zacíná být stávající zpusob testování pomocí rucne navržených a implementovaných testovacích sekvencí nedostatecný. Práce se zabývá automatizací generování techto testovacích sekvencí s využitím principu Model-based testování. Testovací sekvence jsou generovány z modelu specifikovaných casovanými automaty. Soucástí práce je návrh tohoto inovativních testovacího konceptu. Rešení je následne implementováno ve forme testovacího nástroje Taster a také je predstavena nová HIL testovací platforma založená na modulárním hardwaru firmy National Instruments. Overení této metody je provedeno formou dvou prípadových studií. První demonstruje metodu na problému testováním systému bezklícového zapalování, druhá potom testuje reálný systém otvírání pátých dverí automobilu. Klíčová slova: Testování; FlexRay; Parametry; Elektronika Plné texty jsou dostupné v digitálním repozitáři ČVUT. Methods for Verification and Validation of Automotive Distributed Systems

Stále narustající složitost automobilových elektronických systému vytvárí poptávku po vhodných validacních a testovacích metodách. Smerování automobilového prumyslu k plne autonomním vozidlum ...

Novák, Jiří; Sobotka, Jan
České vysoké učení technické v Praze, 2017

Reveal or Hide: Information Sharing in Multi-Agent Planning
Komenda, Antonín; Vokřínek, Jiří; Štolba, Michal
2017 - anglický The ability to plan a sequence of action in order to achieve a given goal with respect to the initial conditions of the world is one of the crucial aspects of intelligence. It is no surprise, that this aspect has been thoroughly studied in the context of artificial intelligence since its very beginning. The same can be said about the study of multi-agent aspects of planning in the research field of multi-agent systems. Among the most important aspects of such multi-agent planning is information sharing, that is, which information should be shared by the agents and which not, and also how to share the information efficiently. We provide several perspectives on the issue of sharing or hiding information in multi-agent planning. We mostly focus on heuristic search with domain-independent heuristics which is a well-established approach both in classical and multi-agent planning. We advance the state of the art in a number of directions. Firstly, we focus on the distributed computation of heuristics. The main research question is how to achieve global heuristic guidance without explicitly communicating and revealing private parts of the planning problems respective to the particular agents. We approach this issue by providing a number of distributed variants of classical planning heuristics, both inadmissible and admissible (which are necessary for optimal planning). We use the acquired knowledge to design more general approaches for distributing relaxation heuristics and finally any heuristic (in an admissible way). We theoretically analyze the distributed heuristics (e.g., by showing their admissibility) and provide a thorough experimental evaluation, showing their superiority in speed or heuristic guidance compared to the same heuristics computed locally by the agents (that is, without sharing any information throughout the heuristic computation). Secondly, we propose a heuristic search algorithm which is able to balance the use of distributed and local heuristics. The distributed heuristic approach is not always the best choice. In many problems, the heuristic guidance of the locally computed heuristic is close to the distributed variant but without the computation and communication overheads. We solve the issue by allowing the search to use the local heuristic while computing the distributed heuristic and waiting for replies from other agents. This technique is able to balance the information sharing in most domains and problems and practically dominates each approach used separately. The resulting planner also improves on the state of the art in suboptimal multi-agent planning. Thirdly, we analyze information sharing in multi-agent planning in the context of privacy. In privacypreserving cooperative multi-agent planning, the agents want to cooperatively plan a sequence of actions but do not want to reveal their private knowledge. In realistic scenarios, avoiding explicit communication of the private information is not enough, the agents do not want to allow any other agent even to deduce such information from the communication protocol. The thesis builds on two major journal publications and a number of works published at the top-tier AI conferences. The designed algorithms are both theoretically analyzed and thoroughly experimentally evaluated. In order to allow for a more complete and rigorous comparison of existing multi-agent planners, we have co-organized the first Competition of Multi-Agent and Distributed Planners (CoDMAP) during the work on the above research topics. We have collaborated on the design of the formal domain and problem description language, we have designed the competition setup (in two tracks), implemented necessary software tools, and performed the evaluation. The description of the competition and the results relevant to other presented topics are provided as a part of the thesis. Plné texty jsou dostupné v digitálním repozitáři ČVUT. Reveal or Hide: Information Sharing in Multi-Agent Planning

The ability to plan a sequence of action in order to achieve a given goal with respect to the initial conditions of the world is one of the crucial aspects of intelligence. It is no surprise, that ...

Komenda, Antonín; Vokřínek, Jiří; Štolba, Michal
České vysoké učení technické v Praze, 2017

Design and Implementation of Hybrid Magnetic Bearing Control Part
Pavelka, Jiří; Kupka, Tomáš
2017 - anglický Experiments with magnetic levitation for stabilization of rotating parts of electrical machines started in the middle of 20th century, but first practical application started with powerful digital microprocessors. Recently, price and quality of micro-controllers and other supporting circuits allow to design a number of magnetic bearings in all power classes. However, more complicated construction (and higher price) classifies magnetic bearings to be used in special applications of high speed and power drives or aggressive ambient or vacuum. There are just a few companies producing magnetic bearings on the worldwide market (e.g. Synchrony Magnetic Bearings, Waukesha Magnetic Bearings, Calnetix Technologies or Levitronix). Industrial using of active magnetic bearings is defined by international standard ISO 14839. The standard describes technical terms, measurement and diagnostic of machine equipped by active magnetic bearings and evaluation criteria. Worldwide there are a few patents and technical papers describing the theory of hybrid magnetic bearings, but a real product still does not take a significant place on the market. Also the industrial standard doesn't describe any flux-combined type of the magnetic bearing. The aim of this doctoral thesis is to analyse capability of the permanent-magnet-based active magnetic bearing with three-phase stator winding. Diagnostic by the international standard for the active magnetic bearing was used as a method of the bearing evaluation features. For this purpose a new electrical part of the hybrid magnetic bearing was designed and constructed. It was driven together with a three-phase magnetic part and tests and diagnostics of the complete system according to the actual international standard were made. It was found that the hybrid magnetic bearings are able to fulfil all requirements of the standard ISO 14839, which proves that they could be used in the same application as active bearings, since the standard defines only the active ones. The practical outcome of this paper is a description of a perspective way how to develop the hybrid magnetic bearing for real industrial applications. Plné texty jsou dostupné v digitálním repozitáři ČVUT. Design and Implementation of Hybrid Magnetic Bearing Control Part

Experiments with magnetic levitation for stabilization of rotating parts of electrical machines started in the middle of 20th century, but first practical application started with powerful digital ...

Pavelka, Jiří; Kupka, Tomáš
České vysoké učení technické v Praze, 2017

Graph and Point Cloud Matching for Image Registration
Kybic, Jan; Pinheiro, Miguel Amável
2017 - anglický This thesis focuses on the topic of image or volume registration of data containing tree and graph shaped structures, with a special focus on medical imaging. The geometrical information is first extracted from the volumes or images and then used for registration. We propose a method for the segmentation of trees in images acquired at different time instances, by enforcing time consistency. This results in an overall improvement of the extraction accuracy. The method was tested on medical, biological and road images. The focus of this thesis is finding the alignment between segmented graphs and trees. We first propose a method called Active Testing Search (ATS) that explores partial correspondences of branching points of the structures. The method estimates the probability of partial match correctness based on training data and incrementally grows these partial matches. The ATS approach was able to align real data from several different medical imaging modalities, and is robust to initial position, rotation, deformation, missing data and noise. The second proposed method is called Graph Matching using Monte Carlo tree search (GMMC). The approach uses a stochastic state-space search algorithm inspired by the Monte Carlo tree search method to build a large set of compatible curves. Further acceleration is achieved by pruning using novel curve descriptors. The method can handle partial matches, topological differences, geometrical distortion, does not use appearance information and foes not require an initial alignment. Moreover, our method is very efficient – it can match graphs with thousands of nodes, which is an order of magnitude better than the best competing method. Plné texty jsou dostupné v digitálním repozitáři ČVUT. Graph and Point Cloud Matching for Image Registration

This thesis focuses on the topic of image or volume registration of data containing tree and graph shaped structures, with a special focus on medical imaging. The geometrical information is first ...

Kybic, Jan; Pinheiro, Miguel Amável
České vysoké učení technické v Praze, 2017

OBJECTS CHARACTERIZATION BY MEANS OF WIDEBAND SIGNALS
Mazánek, Miloš; Kořínek, Tomáš; Kabourek, Václav
2017 - anglický Thesis deals with objects characterization by means of wideband signals. More speci cally, radar cross section and high-resolution images are used to describe scattering behavior of objects in wide frequency band. The aim of this thesis is then to develop a simple method allowing to predict accurate far eld radar cross section of objects from their near eld measurements and subsequently calculate high-resolution images of their contours. According to these facts, appropriate techniques are investigated and thoroughly described. Circular near- eld to far- eld radar cross section prediction technique is selected to correct data obtained from mono-static, near eld measurement of scattered eld of selected electrically large objects. One-plane measurements are undertaken in full anechoic chamber at frequencies ranging from 3 GHz to 18 GHz. Obtained results are then compared to simulated values and discussed. Since test antenna introduces tapering errors into measured radar cross section values, its broadband radiation patterns are computed employing novel antenna impulse response measurement technique. Radiation pattern correction is subsequently employed in proposed overall computational method. Obtained results show good correspondence with simulated patterns. In order to verify its applicability in image processing, images of selected objects are created by means of inverse synthetic aperture radar technique. Following achieved results, presented overall correction scheme is proven to be suitable for both, radar cross section calculation as well for restoring contour of object shape in image domain. Plné texty jsou dostupné v digitálním repozitáři ČVUT. OBJECTS CHARACTERIZATION BY MEANS OF WIDEBAND SIGNALS

Thesis deals with objects characterization by means of wideband signals. More speci cally, radar cross section and high-resolution images are used to describe scattering behavior of objects in wide ...

Mazánek, Miloš; Kořínek, Tomáš; Kabourek, Václav
České vysoké učení technické v Praze, 2017

HVDC circuit breakers modeling in multiterminal grids
Tlustý, Josef; Yanushkevich, Alexander
2017 - anglický Transition towards sustainable energy systems lead to transformation of the existing electrical power grids. One of the key enabling technologies for this transformation is high voltage direct current (HVDC) technology that has range of advantages comparing to today’s AC systems. One of the main obstacles for HVDC grids implementation is lack of robust and reliable protection systems for DC fault clearing. HVDC circuit breaker is a crucial component for DC fault clearing, however, performance of this new technology in multiterminal HVDC grids is not fully understood. Discussed nowadays innovative hybrid circuit breaker solution, that combines mechanical switches and power electronic components, is very different from AC circuit breaker technology. Application of power electronic components for DC fault clearing puts higher requirements on protection system where approach used in AC systems may not be optimal. Alternative multifeeder protection solution is proposed and investigated in the thesis. This solution brings benefitofthe protection system cost reduction and high speed fault clearing capability. In this thesis methods for HVDC components, including converter and circuit breakers, modelling are explained. Developed models are crucial for further protection systems development and optimisation. These models are used for performance investigation of the HVDC circuit breakers in multiterminal HVDC grids, radial and meshed. Results of the simulations performed in the thesis conclude into requirements for protection system and HVDC circuit breakers design. Plné texty jsou dostupné v digitálním repozitáři ČVUT. HVDC circuit breakers modeling in multiterminal grids

Transition towards sustainable energy systems lead to transformation of the existing electrical power grids. One of the key enabling technologies for this transformation is high voltage direct current ...

Tlustý, Josef; Yanushkevich, Alexander
České vysoké učení technické v Praze, 2017

Adaptive data processing in aircraft control
Roháč, Jan; Čelikovský, Sergej; Alam, Mohammad Mushfiqul
2017 - anglický Plné texty jsou dostupné v digitálním repozitáři ČVUT. Adaptive data processing in aircraft control

Roháč, Jan; Čelikovský, Sergej; Alam, Mohammad Mushfiqul
České vysoké učení technické v Praze, 2017

Biocidal effects of non-thermal atmospheric pressure plasma
Kříha, Vítězslav; Čeledová, Vladyslava
2017 - anglický The subject of this Ph.D. thesis covers bio-chemical pathways in plasma activated liquids (PAW), that are under intensive investigation during last decades. Three possible ways of bacteria inactivation with PAW were studied. The DC plasma jet generated plasma in gas phase (N2/O2) during underwater operation was used to provide postdischarge bacteria treatment. The synergistic effect of transition metal ions and reactive oxygen and reactive nitrogen species was considered to play the dominant role in bacteria inactivation. Moreover, toxicity of the copper ions even in sublethal doses should be taken into account, due to possible DNA damages induced in the cell. Direct bacteria treatment with PAW was studied using RF operating APPJ working in He + O2 gas mixture over the bacterial suspension. Reactive oxygen species were assumed to play a major role in bacteria inactivation process through inducing the oxidative stress, that led to DNA damage and viable but non-cultivable state of bacteria. The evidence of peroxidation of lipids in the bilayer was measured; however, we propose, that it did not play a major role in the bactericidal process. The contaminated agar and spinach leaves surface was treated by electrospraying of 3% oregano essential oil (OEO) suspended in 5% polysorbate 80 water solution through the transient spark discharge. The synergistic effect of charged and reactive species carried with micelles onto the surface and phenolic component of OEO was assumed to cause membrane fluidisation and resulted to the cell death.Náplní této práce je studium biocidních úcinku v roztocích vyvolaných pusobením netermálního plazmatu (NTP), jež jsou v posledních letech predmetem intenzivního výzkumu. Ke zjištení odezvy baterie E. coli na chemické procesy, vyvolané pusobením NTP, generovaného v plynné fázi (N2/O2) ale pusobícím pod vodní hladinou, byla použita plazmová tryska napájená zdrojem stejnosmerného napetí. Díky použitému technickému rešení, jež umožnilo prímý kontakt kovového hrotu s ošetrovanou tekutinou, bylo možné sledovat synergické pusobení iontu prechodných kovu a reaktivních kyslíkových a dusíkových cástic na inaktivaci bakterií. Úcinky plazmatu pusobícího nad hladinou bakteriální suspenze byly zkoumány za použití APPJ, generujícího RF plazma v plynné fázi (He + O2). Namerené výsledky poukazují na dominantní roli reaktivních kyslíkových cástic, jež zpusobují oxidacní stres, vedou k poškození DNA a prechodu bakterie do stavu, v nemž je živá ale nekultivovatelná. Inaktivaci mikroorganizmu lze rovnež docílit rozprášením tekutiny aktivované plazmatem na kontaminovaný povrch. K tomuto úcelu byl na listy špenátu pomocí prechodového jiskrového výboje rozprášen 3% roztok silic oregano. Cidní úcinky byly pravdepodobne zpusobené synergickým pusobením náboje prenášeného micely na povrch mikroorganizmu a fenoly OEO zpusobující fluidaci bakteriální membrány. Plné texty jsou dostupné v digitálním repozitáři ČVUT. Biocidal effects of non-thermal atmospheric pressure plasma

The subject of this Ph.D. thesis covers bio-chemical pathways in plasma activated liquids (PAW), that are under intensive investigation during last decades. Three possible ways of ...

Kříha, Vítězslav; Čeledová, Vladyslava
České vysoké učení technické v Praze, 2017

Optimization of optical transmission systems
Lucki, Michal; Agalliu, Rajdi
2017 - anglický This doctoral thesis deals with the design and optimization of optical networks. The two main research areas are optimization of network capacity and transmission rate. The primary goal of the research in network capacity is to investigate all possibilities of utilizing in the most efficient way the available bandwidth without any major network hardware upgrade and to propose new solutions that significantly increase the potential number of subscribers in a given transmission system. The goal of the second part of this thesis is to achieve the highest possible transmission rates. Research in optical transceiver design was done primarily in terms of modulation formats, which play the most significant role in signal transmission over optical media and have a direct impact on transmission rates. Both topics are closely related to each other and they represent the key components of optimizing optical networks. In particular, the main contributions of the doctoral thesis are as follows:  Optimization of the existing solutions in DWDM systems in terms of their transmission rate, network capacity and physical reach.  Investigation of the most promising modulation formats for transponders operating at 100 Gbps and beyond.  Design of dynamic solutions which are capable of supporting different bit rates and channel upgrades from a long-term perspective.  Shrink of the gap between revenues and implementation cost. Maximal utilization of the fiber capacity while minimizing the cost per transmitted data.  Research on network transparency and potential convergence of networks at the physical layer.  Optimization of passive optical network component, such as splitters.  Systematic design of optical networks based on the topology, number of channels, most effective modulation and highest possible throughput. Keywords:Tato disertační práce se zabývá návrhem a optimalizací optických přenosových sítí. Dvě hlavní oblasti výzkumu jsou optimalizace kapacity sítě a přenosové rychlosti. Primárním cílem výzkumu síťové kapacity je prozkoumat všechny možnosti využití dostupné šířky pásma co nejefektivnějším způsobem bez velkých síťových změn a navrhnout nová řešení, která výrazně zvyšují počet účastníků v daném přenosovém systému. Cílem druhé části práce je dosáhnout co nejvyšší možnou přenosovou rychlost. Výzkum v oblasti konstrukce optických přijímačů a vysílačů byl proveden především z hlediska modulačních formátů, které hrají nejvýznamnější roli v přenosu signálu v optických médiích a mají přímý vliv na přenosové rychlosti. Obě témata úzce navazují a představují klíčové prvky optimalizace optických sítí. Hlavní přínosy disertační práce jsou:  Optimalizace stávajících řešení v DWDM systémech z hlediska jejich přenosové rychlosti, kapacity sítě a fyzického dosahu.  Výzkum modulačních formátů pro transpondery pracující na rychlosti 100 Gbps a výšší.  Návrh dynamických řešení, která jsou schopna podporovat různé přenosové rychlosti a optické kanály z dlouhodobého hlediska.  Snižování rozdílu mezi příjmy a náklady implementace. Maximální využití kapacity vlákna při současné minimalizaci nákladů ve vztahu k objemu přenášených dat.  Výzkum v oblasti transparentnosti sítě a potenciální konvergence sítí na fyzické vrstvě.  Optimalizace pasivních komponent optické sítě, jako jsou rozbočovače.  Systematický návrh optických sítí založených na topologii, počtu kanálů, nejefektivnější modulaci a nejvyšší možnou průchodnost. Klíčová slova: Klíčová slova: optical design; optical fiber communication; hybrid TDM/WDM networks; modulation formats; OptSim Plné texty jsou dostupné v digitálním repozitáři ČVUT. Optimization of optical transmission systems

This doctoral thesis deals with the design and optimization of optical networks. The two main research areas are optimization of network capacity and transmission rate. The primary goal of the ...

Lucki, Michal; Agalliu, Rajdi
České vysoké učení technické v Praze, 2017