36 research outputs found

    Multilayer neural network

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    Bakalářská práce popisuje základy problematiky vícevrstvých neuronových sítí a vysvětluje princip fungování algoritmu backpropagation. Další část práce se zabývá vývojem programu pro učení a testování vícevrstvých neuronových sítí a popisem jeho grafického uživatelského rozhraní a principu ovládání. Poslední část práce je věnována výukovým příkladům a praktickým ukázkám využití vícevrstvé neuronové sítě.Bachelor's thesis describes the basics of issue of multilayer neural networks and explains principle of backpropagation algorithm. Next part of thesis is about development of a software for learning and testing multilayer neural networks and describes its graphical user interface. Last part of thesis is dedicated to tutorial examples and practical demonstrations of multilayer neural network usage.

    Molecular Diagnostics of Pulmonary Diseases Based on Analysis of Exhaled Breath Condensate

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    Measurements of biomarkers in exhaled breath condensate (EBC) extend a novel route for monitoring lung physiology and provide a beneficial insight into the pathophysiology of a specific disease. From the medicinal point of view, biomarkers present in EBC depict rather the processes occurring in lungs than those in the entire system. Therefore, particular profiles of exhaled biomarkers (e.g. cys-LTs, LTB4, 8-isoprostane, etc.) apparently reveal information exclusively applicable to differential lung disease diagnoses. This chapter describes the developed analytical method being applied to a clinical study for differential diagnostics of various phenotypes of asthma, chronic obstructive pulmonary disease, lung cancer, etc. In particular, having determined cys-LTs and LXs by the described method, and having applied them as biomarkers of bronchial asthma, their distinctive potential was demonstrated to differentially diagnose the specific disease, clearly suggesting this method to be reckoned as a beneficial alternative to existing diagnostic methods. Consecutively, the developed method was expanded to other asthma markers as aldehydes, nitrotyrosine, 8-isoprostane, PGE2, adenosine and finally, a supplementary study was carried out, engaging in detecting serotonin. The multi-marker screening and importance in the diagnostics of pulmonary diseases are referenced in the text as well

    Forex automated trading system based on neural networks

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    Hlavním cílem této práce je vytvoření forexového automatického obchodního systému s možností přidávat obchodní strategie jako moduly a realizace modulu obchodní strategie založené na neuronových sítích. Implementovaný obchodní systém se skládá z klientské části pro obchodní platformu MetaTrader 4 a ze serverové GUI aplikace. Moduly obchodních strategií jsou realizovány formou dynamických knihoven. Navržená obchodní strategie využívá vícevrstvé neuronové sítě pro predikci směru 45-ti minutového plovoucího průměru zavíracích hodnot ceny v časovém horizontu jedné hodiny. Neuronové sítě byly schopné najít souvislost mezi vstupy a výstupem a predikovat pokles či nárůst s úspěšností vyšší než 50%. Při živém obchodování na demo účtu se pro měnový pár EUR/USD strategie projevila jako zisková, pro měnový pár GBP/USD naopak jako ztrátová. Při testech strategie na historických datech za rok 2014 bylo dosaženo zisku v případě obchodování na měnovém páru EUR/USD ve směru dlouhodobého trendu. Při obchodování proti směru trendu na měnovém páru EUR/USD a ve směru, i proti směru trendu na měnovém páru GBP/USD byla strategie ztrátová.Main goal of this thesis is to create forex automated trading system with possibility to add trading strategies as modules and implementation of trading strategy module based on neural networks. Created trading system is composed of client part for MetaTrader 4 trading platform and server GUI application. Trading strategy modules are implemented as dynamic libraries. Proposed trading strategy uses multilayer neural networks for prediction of direction of 45 minute moving average of close prices in one hour time horizon. Neural networks were able to find relationship between inputs and output and predict drop or growth with success rate higher than 50%. In live demo trading, strategy displayed itself as profitable for currency pair EUR/USD, but it was losing for currency pair GBP/USD. In tests with historical data from year 2014, strategy was profitable for currency pair EUR/USD in case of trading in direction of long-term trend. In case of trading against direction of trend for pair EUR/USD and in case of trading in direction and against direction of trend for pair GBP/USD, strategy was losing.

    Organometallics: Exploration Tool for Surface Phenomena in Heterogeneous Catalysis

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    Homogeneous and heterogeneous catalyses have sufficient common features that are based on the same molecular phenomena, thus permitting them and their benefits to be directed to the same objective. Moreover, conditions that apply to one of them can yield benefits to the other. In this chapter, the progress of combining these advantages is demonstrated on a particular topic of testing a suitable structural model from the field of organometallic compounds, whose structure resembles complexes adsorbed on the surface of heterogeneous catalysts. The adsorbed complexes represent key structures in the conversion of reactants to products, while their demanding structural characterization is one of the main persistent topics of heterogeneously catalyzed reactions. These include compounds procuring a precious mechanistic interpretation of such complex concepts as the catalytic activity and selectivity. The knowledge of the structure of an adsorbed complex leads to a better understanding of the complex surface processes and more precisely defined heterogeneous catalysts. The understanding of processes on the molecular level allows discussing the structure-activity. Analogies and differences between molecular (homogeneous catalysis) and surface (heterogeneous catalysis) chemistry are addressed in this review. The work demonstrates that these two fields are complementary, presenting a large potential for the development of novel and superior catalysts when the advantages of both sub-disciplines are combined

    Asymmetric Transfer Hydrogenation of C=O and C=N Bonds Catalyzed by [Ru(η6 arene)(diamine)] Complexes: A Multilateral Study

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    In these days, asymmetric transfer hydrogenation (ATH) is a very attractive method for synthesis of enantioenriched chiral compounds, especially fine chemicals such as drugs or agrochemicals. In this review, several topics related to the asymmetric transfer hydrogenation of ketones and cyclic or acyclic imines are discussed. Initially, the reaction mechanism of the ATH of ketones and imines, mainly 3,4-dihydroisoquinoline derivates, is examined. Next, typical reaction conditions, structural effects of the catalyst and a substrate, and analytical methods used for ATH monitoring and practical applications of the ATH in the chemical industry are described

    Multimarker Screening of Oxidative Stress in Aging

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    Aging is a complex process of organism decline in physiological functions. There is no clear theory explaining this phenomenon, but the most accepted one is the oxidative stress theory of aging. Biomarkers of oxidative stress, substances, which are formed during oxidative damage of phospholipids, proteins, and nucleic acids, are present in body fluids of diseased people as well as the healthy ones (in a physiological concentration). 8-iso prostaglandin F2α is the most prominent biomarker of phospholipid oxidative damage, o-tyrosine, 3-chlorotyrosine, and 3-nitrotyrosine are biomarkers of protein oxidative damage, and 8-hydroxy-2′-deoxyguanosine and 8-hydroxyguanosine are biomarkers of oxidative damage of nucleic acids. It is thought that the concentration of biomarkers increases as the age of people increases. However, the concentration of biomarkers in body fluids is very low and, therefore, it is necessary to use a sensitive analytical method. A combination of HPLC and MS was chosen to determine biomarker concentration in three groups of healthy people of a different age (twenty, forty, and sixty years) in order to find a difference among the groups

    Oxidative stress markers are elevated in exhaled breath condensate of workers exposed to nanoparticles during iron oxide pigment production

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    PubMed ID: 26828137Markers of oxidative stress and inflammation were analysed in the exhaled breath condensate (EBC) and urine samples of 14 workers (mean age 43  ±  7 years) exposed to iron oxide aerosol for an average of 10  ±  4 years and 14 controls (mean age 39  ±  4 years) by liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry (LC-ESI-MS/MS) after solid-phase extraction. Aerosol exposure in the workplace was measured by particle size spectrometers, a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS), and by aerosol concentration monitors, P-TRAK and DustTRAK DRX. Total aerosol concentrations in workplace locations varied greatly in both time and space. The median mass concentration was 0.083 mg m−3 (IQR 0.063–0.133 mg m−3) and the median particle concentration was 66 800 particles cm−3 (IQR 16 900–86 900 particles cm−3). In addition, more than 80% of particles were smaller than 100 nm in diameter. Markers of oxidative stress, malondialdehyde (MDA), 4-hydroxy-trans-hexenale (HHE), 4-hydroxy-trans-nonenale (HNE), 8-isoProstaglandin F2α (8-isoprostane) and aldehydes C6–C12, in addition to markers of nucleic acid oxidation, including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), and of proteins, such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr) were analysed in EBC and urine by LC-ESI-MS/MS. Almost all markers of lipid, nucleic acid and protein oxidation were elevated in the EBC of workers comparing with control subjects. Elevated markers were MDA, HNE, HHE, C6–C10, 8-isoprostane, 8-OHdG, 8-OHG, 5-OHMeU, 3-ClTyr, 3-NOTyr, o-Tyr (all p  <  0.001), and C11 (p  <  0.05). Only aldehyde C12 and the pH of samples did not differ between groups. Markers in urine were not elevated. These findings suggest the adverse effects of nano iron oxide aerosol exposure and support the utility of oxidative stress biomarkers in EBC. The analysis of urine oxidative stress biomarkers does not support the presence of systemic oxidative stress in iron oxide pigment production workers.Web of Science101art. no. 01600
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