Model of atmospheric transmission media for free space optics

Cílem této práce je prostudovat metody návrhu optického bezkabelového spoje a jeho využití v komunikačních technologiích. Práce popisuje možné rušivé vlivy na přenášený optický signál, mezi něž patří šum signálu, útlum atmosféry a atmosférické turbulence. Práce se podrobně zaměřuje na vlivy atmosférických turbulencí a útlum atmosféry na optický svazek.The aim of this thesis is to study the methods of a free space optical link design and its application in the communication technologies. The thesis describes possible intrusive influences on the transmitted optical signal, which are the signal noise, atmospheric attenuation and atmospheric turbulences. The thesis is particulary focused on the influence of the atmospheric turbulences and atmospheric attenuation on the optical beam.

Comparison of success rate of multi-channel methods of speech signal separation

Separace nezávislých zdrojů signálů ze směsí zaznamenaných dat je základní problém v mnoha praktických situacích. Typický příklad je záznam řeči v prostředí za přítomnosti šumu či jiného mluvčího na pozadí. Touto problematikou se zabývá skupina metod nazvaných Separace zdrojů naslepo. Slepá separace je založena na odhadu N neznámých zdrojů z P měření, které jsou směsmi těchto neznámých zdrojů a neznámého prostředí. Představeny a v Matlabu implementovány jsou některé známé řešení okamžitých směsí, tj. Analýza nezávislých komponent a Časově kmitočtová analýza. V reálném prostředí však akustické signály nejsou okamžité směsi, ale směsi konvoluční. Pro tento případje představen a v Matlabu implementován algoritmus pro separaci konvolučních směsí v kmitočtové oblasti.Tato diplomová práce zkoumá porovnání a použitelnost těchto separačních algoritmů.The separation of independent sources from mixed observed data is a fundamental problem in many practical situations. A typical example is speech recordings made in an acoustic environment in the presence of background noise or other speakers. Problems of signal separation are explored by a group of methods called Blind Source Separation. Blind Source Separation (BSS) consists on estimating a set of N unknown sources from P observations resulting from the mixture of these sources and unknown background. Some existing solutions for instantaneous mixtures are reviewed and in Matlab implemented , i.e Independent Componnent Analysis (ICA) and Time-Frequency Analysis (TF). The acoustic signals recorded in real environment are not instantaneous, but convolutive mixtures. In this case, an ICA algorithm for separation of convolutive mixtures in frequency domain is introduced and in Matlab implemented. This diploma thesis examines the useability and comparisn of proposed separation algorithms.

Web Interface for Graphics Demo

Tato práce se zabývá návrhem a implementací webového rozhraní pro demonstraci programů na zpracování obrazu. Představuje systém propojení jazyka PHP s C++ za pomoci XML souborů. Rozhraní umožňuje uživateli snadné spuštění a instalaci vlastních programů.This thesis describes the design and implementation of web interface for demonstration programs for image processing. Introducing system for linking PHP to C++ using XML files. The interface allows user to easily run and install their own programs.

Modelling of Twin Rotor MIMO System

The paper deals with modelling of a Twin Rotor MIMO System-a laboratory model constructed by Feedback Instruments Ltd. The system consists of a two rotors which resembles a simple helicopter. The non-stationary part of the model can rotate around two perpendicular axes to produce azimuth and elevation output of the system. These outputs are affected by speed of the rotors. Significant cross-coupling can be observed and the system behaviour is nonlinear. A model based on first-principle modelling was derived and is parameters were refined by identification based on real-time experiments. Resulting model was designed in MATLAB/Simulink environment and can serve for control design. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

Slow-Release Nitrogen Fertilizers with Biodegradable Poly(3-hydroxybutyrate) Coating: Their Effect on the Growth of Maize and the Dynamics of N Release in Soil

Fertilizers play an essential role in agriculture due to the rising food demand. However, high input fertilizer concentration and the non-controlled leaching of nutrients cause an unwanted increase in reactive, unassimilated nitrogen and induce environmental pollution. This paper investigates the preparation and properties of slow-release fertilizer with fully biodegradable poly(3-hydroxybutyrate) coating that releases nitrogen gradually and is not a pollutant for soil. Nitrogen fertilizer (calcium ammonium nitrate) was pelletized with selected filler materials (poly(3-hydroxybutyrate), struvite, dried biomass). Pellets were coated with a solution of poly(3-hydroxybutyrate) in dioxolane that formed a high-quality and thin polymer coating. Coated pellets were tested in aqueous and soil environments. Some coated pellets showed excellent resistance even after 76 days in water, where only 20% of the ammonium nitrate was released. Pot experiments in Mitscherlich vegetation vessels monitored the effect of the application of coated fertilizers on the development and growth of maize and the dynamics of N release in the soil. We found that the use of our coated fertilizers in maize nutrition is a suitable way to supply nutrients to plants concerning their needs and that the poly(3-hydroxybutyrate) that was used for the coating does not adversely affect the growth of maize plants

Effect of Iron Overload and Iron Deficiency on Liver Hemojuvelin Protein

INTRODUCTION: Hemojuvelin (Hjv) is a key component of the signaling cascade that regulates liver hepcidin (Hamp) expression. The purpose of this study was to determine Hjv protein levels in mice and rats subjected to iron overload and iron deficiency. METHODS: C57BL/6 mice were injected with iron (200 mg/kg); iron deficiency was induced by feeding of an iron-deficient diet, or by repeated phlebotomies. Erythropoietin (EPO)-treated mice were administered recombinant EPO at 50 U/mouse. Wistar rats were injected with iron (1200 mg/kg), or fed an iron-deficient diet. Hjv protein was determined by immunoblotting, liver samples from Hjv-/- mice were used as negative controls. Mouse plasma Hjv content was determined by a commercial ELISA kit. RESULTS: Liver crude membrane fraction from both mice and rats displayed a major Hjv-specific band at 35 kDa, and a weaker band of 20 kDa. In mice, the intensity of these bands was not changed following iron injection, repeated bleeding, low iron diet or EPO administration. No change in liver crude membrane Hjv protein was observed in iron-treated or iron-deficient rats. ELISA assay for mouse plasma Hjv did not show significant difference between Hjv+/+ and Hjv-/- mice. Liver Hamp mRNA, Bmp6 mRNA and Id1 mRNA displayed the expected response to iron overload and iron deficiency. EPO treatment decreased Id1 mRNA, suggesting possible participation of the bone morphogenetic protein pathway in EPO-mediated downregulation of Hamp mRNA. DISCUSSION: Since no differences between Hjv protein levels were found following various experimental manipulations of body iron status, the results indicate that, in vivo, substantial changes in Hamp mRNA can occur without noticeable changes of membrane hemojuvelin content. Therefore, modulation of hemojuvelin protein content apparently does not represent the limiting step in the control of Hamp gene expression