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Expertní detekce příchodu signálu AE
Chlada, Milan
Accurate acoustic emission (AE) source location is the primary goal of the defect anylysis following the AE signal detection. The source localization is mostly based on arrival time differences of signals recorded by several transducers. Considerable signal distortion happens during the wave propagation through the solid. Inaccurate determination of signal onset and arrival time differences respectively, are the greatest sources of localization errors.Especially, in a case of figher requirements on accuracy and robustness, the results of currently used localization methods appear to be insufficient. In the paper, recently improved version of the new signal-shape based algorithm, modelling an expert system of the elastic wave arrival detection, is introduced. In many applications, this method, based on signal energy and local gravity center evolution, has been proved as rugged enough, fast and easily applicable.
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Material defect cost by large plastic deformations
Marek, Pavel ; Brož, P.
The main aim of this paper is to demonstrate the use of algorithms to tackle the large plastic deformation problems of engineering structures. The source materials are presently to be a tool for putting together the full probabilistic methodology, especially the strength of SBRA method, to check the above characteristics of the structural systems.
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Side-chain Side-chain Interactions in Proteins
Berka, Karel ; Hobza, Pavel (advisor) ; Rulíšek, Lubomír (referee) ; Otyepka, Michal (referee)
Charles University in Prague Faculty of Science Department of Physical and Macromolecular Chemistry Side-chain Side-chain Interactions in Proteins Doctoral Thesis Abstract RNDr. Karel Berka Supervisors: Prof. Ing. Pavel Hobza, DrSc., FRSC RNDr. Jiří Vondrášek, CSc. Institute of Organic Chemistry and Biochemistry AS CR Center for Biomolecules and Complex Molecular Systems Praha 2009 2 Introduction Proteins are the most versatile and useful molecules in the cellular arsenal. They are the best catalysts the nature knows. Proteins cover the biggest amount of the cellular functions with range from metabolism and signaling through cell architecture to DNA replication. Variations of their structure and functions are amazing. And yet, they are built from simple building blocks - amino acids. Each amino acid has many possibilities of interactions with its neighborhood and the sequential context manifested through these possibilities is the main reason for the structure variability. The experimental investigation of the character and relative strength of interactions between amino acid residues is difficult. On the other hand, theoretical chemistry methods and techniques of are well suited for such task. They can provide useful information about structure, stability and nature of these interactions. The aim of the...
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Detection of angular distribution of the signal electrons in VLESEM
Horáček, Miroslav
The aim of this work is to design a detector for the angle and energy-selective detection of signal electrons in very low energy scanning electron microscopy (VLESEM), based on the directly electron-bombarded CCD sensor (EBCCD). The planar CCD sensor is very suitable for conversion of the area information carried by impinging electrons of the signal beam into the electrical signal that can be further processed.
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Molecular mechanisms of signal transduction by the ERK signaling cascade.
Bráborec, Vojtěch ; Rösel, Daniel (referee) ; Vomastek, Tomáš (advisor)
The MAPK (mitogen-activated protein kinase) cascade represents an evolutionary conserved mechanism by which cells sense extracellular signals and convert them into variety of context-dependent responses. The best studied member of the MAPK protein family is protein kinase ERK (extracellular signal-regulated kinase). Together with protein kinases Raf and MEK (MAPK/ERK kinase) comprise a prototypical signaling pathway which regulates broad-spectrum of biological processes such as cellular proliferation, differentiation, cellular migration, adhesion or apoptosis. To modulate such a multitude of distinct responses by a single pathway, cells utilize mechanisms such as signal strength and duration, distinct protein localization, communication with other signaling pathways, differential substrate selection and the selection of interactive partners. All presented means of regulation are influenced by proteins with non-enzymatic functions - scaffold proteins, protein inhibitors and anchoring proteins. These protein modulators channel the signals leading to particular cellular response, and thus represent the key element of signal transduction. Despite increasing importance of protein modulators in cellular signaling, their biological roles remain mostly unknown. The physiological importance of protein modulators is...
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Analyses of remote sensing techniques for detecting quartz and calcite in rock
Šourková, Lucie ; Štefanová, Eva (advisor) ; Pavelka, Karel (referee)
Remote sensing technique in geology is relatively fast and low cost procedure for initial research method preceding a more detailed field campaign. Remote sensing offer an excellent method of mapping surface geology mainly in arid regions. The analysis of remote sensing methods for silicon and calcium detection is the aims this thesis. The method were tested on satellite sensors Aster and Landsat ETM+ in Sechura desert region in northwest of Peru. For solution to mineral detection was the Aster data the most suitable. The data was preprocessed. From the atmospheric correction method was chosen the Empirical Line Calibration. The best methods for good identification of silicate and calcite were: mineralogic combination 5/7-5/4- 3/1 ETM+ bands, color composite ratio bands Aster 13/10-13/14-12/13, Principal Component Analyses and classification Spectral Angle Mapper. On the strength of results was suggested metodical procedure including steps from preprocessing to classification. Powered by TCPDF (www.tcpdf.org)
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Processing of undersampled blade signals
Balda, Miroslav
The paper deals with a method of processing samples of instantaneous positions of blades of a turbine wheel when passing along a sensor attached to the stator of the turbine. The signals are highly undersampled, since the natural frequencies of blades are much higher than the sampling frequency. The paper reveals the way of signal reconstruction based on a priory knowledge of the blade natural frequencies.
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Biosensors for Environmental Monitoring and Biomedical Applications
ŠTOFIK, Marcel
Study of biosensors has become an essential part of research in biotechnology. Biosensors as fast, portable, highly sensitive, and low-cost bioanalytical detection devices have been utilized in many fields of human activity. The first part of the presented work focuses on electrochemical biosensors for rapid environmental screening of herbicides as water pollutants. A sol-gel immobilization method for a photosystem II (PSII) complex is studied in order to enhance the sensitivity and the signal strength and stability of a PSII-based biosensor. Computer simulations of a PSII biosensor are employed with the aim to find out how the immobilization membrane properties influence the biosensor parameters. Newly developed immobilization by a thin-layer membrane based on the results of computer simulations and revised measurement protocols are presented. The second part of the work is devoted to synthesis and electrochemical detection of newly developed metal labels for electrochemical immunosensors. The synthesis of dendrimer-encapsulated silver nanoparticles and biorecognition properties of biotin-nanocomposite conjugates are discussed. For detection of synthesized labels, a microfluidic detector was manufactured and tested and different approaches to packing of a microfluidic chip employing polydimethylsiloxane (PDMS) were investigated. Newly designed microstructures for a microfluidic separator of magnetic beads (MBs) were studied by computer simulations. The separator was made and trapping of MBs for the further employment in MBs-based immunoassays are presented
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Precipitation variability in the czech land since ad 1500. How strong is the signal contained within documentary sources?
Dobrovolný, Petr ; Brázdil, Rudolf ; Trnka, Miroslav ; Kotyza, O. ; Valášek, H.
Past climate may be reconstructed from a number of proxies. Some of them are “natural archives”, such as tree rings, ice cores and boreholes, most of which are sensitive to air temperature. Other valuable information can be also found in “man-made archives”. Various sources of documentary data very oft en refer not only to temperature but also to other aspects of past weather and climate, such as dry and wet periods. We use the long and homogeneous precipitation series from the recent instrumental period to calibrate precipitation indices derived from older documentary sources. Th e primary objective of this contribution is to provide a quantitative reconstruction of precipitation in the Czech Lands for the last 500 years. Calibration and verifi cation statistics are used to evaluate the strength of the signal. Reconstructed precipitation series are compared with similar Central European documentary-based reconstructions, as well as with reconstructions based on a range of natural proxies.
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Comparison of Tree Edit Distance Algorithms
Ivkin, Egor ; Nečaský, Martin (advisor) ; Lokoč, Jakub (referee)
The aim of this thesis is the comparison of the Tree Edit Distance methods, in the context of detecting structural similarity between two XML Schema documents. The methods search the minimum number of edit operations leading from one tree to another. We have analysed and implemented a wide range of the existing tree edit distance approaches. It is important to understand that the distance computed by the algorithms is affected by the set of used edit operations, therefore the strength in detecting XML Schema similarity differs in each approach. The first part of this work contains the description of the used approaches and necessary notations. The second part provides implementation details and analysis of the described methods, which consists of theoretical comparison and empirical evaluation on real and synthetic xml data. The resulting implementation is available in the form of Java SE application.
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