1,720,989 research outputs found
Ivan Hlinka and creating a cult of personality in the media during the success in Nagano and after his tragic death.
No full textMy diploma thesis is dedicated to the problem of creating a cult of personality around ice hockey coach Ivan Hlinka. It is focused on two key periods: The first is the victory of the Czech ice hockey team at the Olympic Winter Games in Nagano in February 1998 , the second is the period after Hlinka's tragic death in August 2004. The aim of the thesis is to analyze how much media influence the creation of a cult of personality by reporting about these two events. Objects of interest of my thesis are the process that puts a coach almost into the role of national hero . The second aspect of the work is the tabloidization of the topic such as a tragic accident and subsequent Hlinka's death. The thesis defines a cult of personality generaly and also from a historical perspective and adds the most famous reprsentative of cult of personality - Soviet dictator Josif Vissarionovich Stalin. In addition, it is dedicated to the cult of personality of athletes in general. This thesis not only presents Ivan Hlinka from a hockey standpoint, but mentions also his personality through a conversation with his longtime friend Josef Beránek sr. The final analysis is devoted to the representation of Ivan Hlinka in two specific print media during the two selected periods
Depth-resolved quantitative phase imaging using lensfree interferometric microscopy
Full text linkSchopnost zkoumat slabě rozptylující vzorky je klíčová například pro odvětví zabývající se studiem buněk nebo optickou analýzou povrchů. Tyto tzv. fázové objekty však neprodukují dostatečný signál na to, aby mohly být zobrazovány pomocí klasické optické mikroskopie. Řešením tohoto problému je využití interferometrie. Bezobjektivový interferometrický mikroskop (LIM) je zařízením, které využívá dvojlomných krystalů a částečně koherentních, kolimovaných zdrojů světla ke zkoumání plošného rozložení indexu lomu ve vzorcích s vysokým axiálním rozlišením. Schopnost získat informace o třírozměrném rozložení fázových objektů v objemu vzorku by umožnila využití tohoto mikroskopu v nových vědeckých i průmyslových odvětvích, například biomedicínském zobrazování, datových úložištích na bázi skla nebo monitorování defektů v optických elementech. Tato diplomová práce se zabývá rozšířením funkčnosti bezobjektivového interferometrického mikroskopu do oblasti tomografického zobrazování. Toho je dosaženo realizací hloubkového rozlišování pro fázové objekty ve zkoumaných vzorcích. Pro umožnění měření byl sestaven prototyp mikroskopu a ověřen vliv různých parametrů optického uspořádání na kvalitu pořízeného obrazu. Současně byla navržena nová metoda k získání nakloněného, kolimovaného osvětlení. Kombinací několika úhlů osvitu a následného algoritmického zpracování získaných dat byly pořízeny kvantitativní fázové snímky se zorným polem 35 mm2, plošným rozlišením 10 um a axiálním rozlišením menším než 1 nm. Následně bylo navrženo několik metod umožňujících hloubkové rozlišování zobrazovaných objektů. Tyto postupy, využívající nakloněného osvitu a numerické propagace optického pole, byly implementovány a ověřeny měřením na vícevrstvých vzorcích. Nejlepší výsledky byly získány pomocí metody backpropagated pixel-by-pixel verification (beta-PbP). Tato nově navržená metoda byla úspěšně využita pro třírozměrnou rekonstrukci rozložení fázových objektů ve vzorcích objemu V = 0.5 cm3 s axiální přesností menší než 1 mm. Společně s ostatními navrženými metodami se jedná o první demonstraci využití LIM jako tomografické zobrazovací techniky.Examining of weakly scattering transparent structures is highly desirable especially in areas such as cell imaging and quality control of transparent surfaces. However, such structures can not be efficiently imaged in conventional light microscopes due to low scattering signal. To measure such structures, techniques such as interferometry are more suitable. The lensfree interferometric microscope (LIM) is a compact device that utilizes birefringent crystals and partially coherent collimated light beams to acquire information about refractive index distribution of planar samples with sub-nanometer precision. Extending the phase imaging ability of such device from two to three dimensions would allow multitude of new applications across various research and industrial fields including biomedical imaging, physical data storage systems, defect mapping in glasses or holographic security element validation. This thesis focuses on expanding the measurement capabilities of the LIM device into the field of tomographical imaging by enabling depth resolving of transparent (phase) objects. First, an overview of the LIM, its design and related computational methods is provided. The microscope prototype was built, all the optical setup parameters were assessed and the influence of different components was evaluated, laying the foundation for further development of commercial prototypes. To emphasize the potential for a point-of-care portable device, all the hardware controls and data processing were implemented on a single-board computer. Simultaneously, a novel solution to obtain different illumination angles was proposed using multicore optical fiber bundle. Utilizing a combination of the multiple illumination angles and computational post-processing, phase maps were reconstructed across a field-of-view of 35 mm2 with spatial resolution of 10 um and axial resolution in the sub-nanometer region. To enable depth resolving, multiple techniques were proposed for the LIM, taking advantage of both digital holographic refocusing and the angled illumination. These proposed methods were verified by measuring real, custom-made multilayered transparent samples. The best results were obtained by a self-developed algorithm named backpropagated pixel-by-pixel verification (beta-PbP). This new method enables layer-by-layer phase map reconstruction in the sample volume V = 0.5 cm3 with axial accuracy for preliminary results being below 1 mm. Together with the other introduced techniques, this demonstrates the first proof-of-concept of using the LIM for tomographical imaging
Investigation of interactions between graphene and borane clusters as a function of electric charge and dipole moment
No full textPraktické aplikace grafenu, hlavně v odvětví senzoriky a v optoelektronice, jsou podmíněny porozuměním tomu, jaké jsou interakce mezi samotným uhlíkovým nanomateriálem a vnějšími adsorbovanými molekulami a jak tyto interakce ovlivňují některé důležité vlastnosti grafenu. V první části své bakalářské práce shrnuji vybrané základní poznatky z fyziky pevných látek, které jsou následně využity při popisu obecných, chemických i fyzikálních vlastností využívaných látek a materiálů. Vlastní kapitola je věnována grafenu, jeho elektronové pásové struktuře a specifickým vlastnostem, které se týkají epitaxního grafenu na karbidu křemíku. Samostatné shrnutí je také věnováno mezimolekulárním nevazebným interakcím, které jsou hlavním zprostředkovatelem vazby mezi uhlíkovým povrchem a karboranovými klastry, a tomu, jak ovlivňují vlastnosti tohoto 2D uhlíkového alotropu. Krátký přehled byl také věnován využitým analytickým metodám a souhrnu toho, jaká jsou specifika při využití těchto metod na modelovém systému grafen/SiC. V praktické části byla provedena depozice rozdílných karboranových klastrů na grafen a samotná míra interakce byla měřena pomocí metody AFM a KPFM. Bylo změřeno, že pro fyzisorbované molekuly bez funkčních chemických skupin nedochází k jejich jednotné orientaci, která je klíčová pro cílenou modifikaci výstupní práce povrchu, nezávisle na tom, jak jsou rozloženy uhlíkové atomy v molekule. Dále byl měřením experimentálně potvrzen předpoklad, že vliv deponovaných alkalických kovů z karboranových solí na výstupní práci je výrazně větší, než efekt samotných organických molekul.Understanding the interactions at the interface of graphene and adsorbed molecules is essential for further development of novel electronic and sensoric devices. In first section of my bachelor thesis, I summarize selected topics from solid state physics, which are later utilized to explain some of the properties of used materials. One chapter is devoted to graphene, its electronic and band structure and to specific properties of epitaxial graphene grown on silicon carbide. Brief summary is also concluded on non-covalent interactions and how they impact the properties of graphene. Some basic concepts are also recapped in regards to the used analytical methods and their specifics during the graphene/SiC measuring utilized in the following chapters. In experimental part of my bachelor thesis, the effect of various carborane clusters on graphene surface was measured. It is shown that due to the lack of chemical functionalization, there is no preferred ordering of dipoles in the layer of all the tested isomers. This highlights the necessity of such functionalization for precise tuning of graphene work function. It is also shown that alkali metals induce much stronger change to the graphene work function compared to the carborane clusters
Neuromorphic nanophotonic systems for artificial intelligence
Full text linkOver the last decade, we have witnessed an astonishing pace of development in the field of artificial intelligence (AI), followed by proliferation of AI algorithms into virtually every domain of our society. While modern AI models boast impressive performance, they also require massive amounts of energy and resources for operation. This is further fuelling the research into AI-specific, optimised computing hardware. At the same time, the remarkable energy efficiency of the brain brings an interesting question: Can we further borrow from the working principles of biological intelligence to realise a more efficient artificial intelligence? This can be considered as the main research question in the field of neuromorphic engineering. Thanks to the developments in AI and recent advancements in the field of photonics and photonic integration, research into light-powered implementations of neuromorphic hardware has recently experienced a significant uptick of interest. In such hardware, the aim is to seize some of the highly desirable properties of photonics not just for communication, but also to perform computation. Neurons in the brain frequently process information (compute) and communicate using action potentials, which are brief voltage spikes that encode information in the temporal domain. Similar dynamical behaviour can be elicited in some photonic devices, at speeds multiple orders of magnitude higher. Such devices with the capability of neuron-like spiking are of significant research interest for the field of neuromorphic photonics. Two distinct types of such excitable, spiking systems operating with optical signals are studied and investigated in this thesis. First, a vertical cavity surface emitting laser (VCSEL) can be operated under a specific set of conditions to realise a high-speed, all-optical excitable photonic neuron that operates at standard telecom wavelengths. The photonic VCSEL-neuron was dynamically characterised and various information encoding mechanisms were studied in this device. In particular, a spiking rate-coding regime of operation was experimentally demonstrated, and its viability for performing spiking domain conversion of digital images was explored. Furthermore, for the first time, a joint architecture utilising a VCSEL-neuron coupled to a photonic integrated circuit (PIC) silicon microring weight bank was experimentally demonstrated in two different functional layouts. Second, an optoelectronic (O/E/O) circuit based upon a resonant tunnelling diode (RTD) was introduced. Two different types of RTD devices were studied experimentally:a higher output power, µ-scale RTD that was RF coupled to an active photodetector and a VCSEL (this layout is referred to as a PRL node); and a simplified, photosensitive RTD with nanoscale injector that was RF coupled to a VCSEL (referred to as a nanopRL node). Hallmark excitable behaviours were studied in both devices, including excitability thresholding and refractory periods. Furthermore, a more exotic resonate and-fire dynamical behaviour was also reported in the nano-pRL device. Finally, a modular numerical model of the RTD was introduced, and various information processing methods were demonstrated using both a single RTD spiking node, as well as a perceptron-type spiking neural network with physical models of optoelectronic RTD nodes serving as artificial spiking neurons.Over the last decade, we have witnessed an astonishing pace of development in the field of artificial intelligence (AI), followed by proliferation of AI algorithms into virtually every domain of our society. While modern AI models boast impressive performance, they also require massive amounts of energy and resources for operation. This is further fuelling the research into AI-specific, optimised computing hardware. At the same time, the remarkable energy efficiency of the brain brings an interesting question: Can we further borrow from the working principles of biological intelligence to realise a more efficient artificial intelligence? This can be considered as the main research question in the field of neuromorphic engineering. Thanks to the developments in AI and recent advancements in the field of photonics and photonic integration, research into light-powered implementations of neuromorphic hardware has recently experienced a significant uptick of interest. In such hardware, the aim is to seize some of the highly desirable properties of photonics not just for communication, but also to perform computation. Neurons in the brain frequently process information (compute) and communicate using action potentials, which are brief voltage spikes that encode information in the temporal domain. Similar dynamical behaviour can be elicited in some photonic devices, at speeds multiple orders of magnitude higher. Such devices with the capability of neuron-like spiking are of significant research interest for the field of neuromorphic photonics. Two distinct types of such excitable, spiking systems operating with optical signals are studied and investigated in this thesis. First, a vertical cavity surface emitting laser (VCSEL) can be operated under a specific set of conditions to realise a high-speed, all-optical excitable photonic neuron that operates at standard telecom wavelengths. The photonic VCSEL-neuron was dynamically characterised and various information encoding mechanisms were studied in this device. In particular, a spiking rate-coding regime of operation was experimentally demonstrated, and its viability for performing spiking domain conversion of digital images was explored. Furthermore, for the first time, a joint architecture utilising a VCSEL-neuron coupled to a photonic integrated circuit (PIC) silicon microring weight bank was experimentally demonstrated in two different functional layouts. Second, an optoelectronic (O/E/O) circuit based upon a resonant tunnelling diode (RTD) was introduced. Two different types of RTD devices were studied experimentally:a higher output power, µ-scale RTD that was RF coupled to an active photodetector and a VCSEL (this layout is referred to as a PRL node); and a simplified, photosensitive RTD with nanoscale injector that was RF coupled to a VCSEL (referred to as a nanopRL node). Hallmark excitable behaviours were studied in both devices, including excitability thresholding and refractory periods. Furthermore, a more exotic resonate and-fire dynamical behaviour was also reported in the nano-pRL device. Finally, a modular numerical model of the RTD was introduced, and various information processing methods were demonstrated using both a single RTD spiking node, as well as a perceptron-type spiking neural network with physical models of optoelectronic RTD nodes serving as artificial spiking neurons
History and the importance of ice hockey in Litvínov in the 1960s and 1970s
Full text linkkatedra: KHI; přílohy: 1 CD ROM; rozsah: 74 s.Cílem práce je analýza historie litvínovského hokeje od jeho počátků s důrazem na 60. léta 20. století. Práce je zaměřena na zrod hokeje na Litvínovsku v tamnějším Sokole za tzv. První republiky a na vznik oddílu po druhé světové válce
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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