218 research outputs found

    Identification of Quasi-Stationary Dynamic Objects with the Use of Derivative Disproportion Functions

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    This paper presents an algorithm for designing a cryptographic system, in which the derivative disproportion functions (key functions) are used. This cryptographic system is used for an operative identification of a differential equation describing the movement of quasi-stationary objects. The symbols to be transmitted are encrypted by the sum of at least two of these functions combined with random coefficients. A new algorithm is proposed for decoding the received messages making use of important properties of the derivative disproportion functions

    Fragment-aided recognition of images under poor lighting and additive impulse noises

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    On the base of the first-order integral disproportion functions, two algorithms recognizing fragments of standard images are proposed. Due to the disproportion functions techniques, the algorithms have special advantages when processing poorly lighted images, as well as with signals transmitted in the presence of additive impulse noises

    Engineering Dynamics and Life Sciences

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    From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

    Advances in Robotics, Automation and Control

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    The book presents an excellent overview of the recent developments in the different areas of Robotics, Automation and Control. Through its 24 chapters, this book presents topics related to control and robot design; it also introduces new mathematical tools and techniques devoted to improve the system modeling and control. An important point is the use of rational agents and heuristic techniques to cope with the computational complexity required for controlling complex systems. Through this book, we also find navigation and vision algorithms, automatic handwritten comprehension and speech recognition systems that will be included in the next generation of productive systems developed by man

    Social work with airports passengers

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    Social work at the airport is in to offer to passengers social services. The main methodological position is that people are under stress, which characterized by a particular set of characteristics in appearance and behavior. In such circumstances passenger attracts in his actions some attention. Only person whom he trusts can help him with the documents or psychologically

    Functional magnetic resonance imaging : an intermediary between behavior and neural activity

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    Blood oxygen level dependent (BOLD) functional magnetic resonance imaging is a non-invasive technique used to trace changes in neural dynamics in reaction to mental activity caused by perceptual, motor or cognitive tasks. The BOLD response is a complex signal, a consequence of a series of physiological events regulated by increased neural activity. A method to infer from the BOLD signal onto underlying neuronal activity (hemodynamic inverse problem) is proposed in Chapter 2 under the assumption of a previously proposed mathematical model on the transduction of neural activity to the BOLD signal. Also, in this chapter we clarify the meaning of the neural activity function used as the input for an intrinsic dynamic system which can be viewed as an advanced substitute for the impulse response function. Chapter 3 describes an approach for recovering neural timing information (mental chronometry) in an object interaction decision task via solving the hemodynamic inverse problem. In contrast to the hemodynamic level, at the neural level, we were able to determine statistically significant latencies in activation between functional units in the model used. In Chapter 4, two approaches for regularization parameter tuning in a regularized-regression analysis are compared in an attempt to find the optimal amount of smoothing to be imposed on fMRI data in determining an empirical hemodynamic response function. We found that the noise autocorrelation structure can be improved by tuning the regularization parameter but the whitening-based criterion provides too much smoothing when compared to cross-validation. Chapter~5 illustrates that the smoothing techniques proposed in Chapter 4 can be useful in the issue of correlating behavioral and hemodynamic characteristics. Specifically, Chapter 5, based on the smoothing techniques from Chapter 4, seeks to correlate several parameters characterizing the hemodynamic response in Broca's area to behavioral measures in a naming task. In particular, a condition for independence between two routes of converting print to speech in a dual route cognitive model was verified in terms of hemodynamic parameters

    Electrochemical investigation of electron-transfer cascades for the development of solar energy conversion based on artificial photosynthesis

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    Natural Photosynthesis process is the source of life; it converts the sunlight into chemical energy. This process takes place in the chloroplast of the green plants in a sophisticated and complex pathway. It involves electron transfer cascades from the photoexcited reaction centre to sustainable energy storage. As a route to develop new chemical systems for artificial photosynthesis in an efficient and fast electron transfer cascade, it is essential to propose three-dimensional molecular ensembles of both electrochemically and photochemically active systems.This thesis studies the behaviour of using L-cysteine and potassium iodide as electroactive species in a reduction reaction of chlorpromazine hydrochloride on glassy carbon electrodes and rotating glassy carbon disk electrodes with the aid of cyclic voltammetry and linear sweep voltammetry.The electrochemical characteristics of chlorpromazine hydrochloride (CPZ.HCl) in various concentrations, which induce catalytic oxidation reactions of different concentrations of the electroactive materials, are investigated. The experimental results show that the increase in oxidation peaks current of chlorpromazine hydrochloride depends on the concentrations of L-cysteine and potassium iodide. The current response was enhanced through fast transport via a rotating glassy carbon disk electrode. The peak potentials of chlorpromazine hydrochloride in the solution containing L-cysteine shift to more negative values for all concentrations and speeds; similarly for potassium iodide. The electrochemical reaction of chlorpromazine hydrochloride with the electroactive materials determined EC’ reactions. The diffusion coefficient for chlorpromazine hydrochloride was found to be 1.28×10-6 m2 s-1. This thesis studies the adsorption and electrochemical investigation of one of the derivatives of chlorophyll – chlorophyllin, at gold and glassy carbon electrodes. Parameters such as the adsorption time, the electrolyte nature and concentration and chlorophyllin concentration were investigated. The use of chlorophyllin as a redox mediator was examined, with a gold electrode being employed. The importance of gold electrode surface preparation in determining the mechanism of redox was described, and the environment of adsorption process of the different concentrations of chlorophyllin on the surface of the gold electrode had been elucidated in this study. The electrochemical method shows that the cyclic voltammetry responses of studied adsorption chlorophyllin pigment on the gold electrode were more efficient than glassy carbon electrode, with processes being more favourable in aqueous solution.Third, the oxidation reaction of various concentrations of chlorophyllin is investigated in the bulk solution in the presence of Triton X 100 and potassium iodide. The extraction and identification of chlorophyll in fresh spinach were examined by using thin layer chromatography and UV-visible spectrophotometry techniques. The cyclic voltammetry for this pigment was elucidated in the presence of Triton X 100 and vitamin K1 at the gold electrode, the mechanism of this reaction was suggested to be EC’.Lastly, this study has emphasised chlorophyll a and Total chlorophyll (Tchl), based on the effect of electrode materials and diameter, pH, solvent and electrolyte. The inducing of electron transfer of Tchl pigment was examined in presence and absence of vitamin K1 through light and dark atmosphere. The system of chlorpromazine-lyotropic liquid crystal (CPZ-LLC) was highlighted in this thesis. The effect of parameters such as electrode materials, electrode diameters and CPZ.HCl concentrations in this system have been documented. The self-assembled phase was recorded using polarising optical microscopy and X-ray scattering. The CPZ-LLC system was fabrication into photogalvanic cells. The power conversion efficiency (PCE) of this cell is (0.58%), which is useful and novel

    A contribution to the experimental validation in Lorentz force eddy current testing

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    Nondestructive testing (NDT) of electrically conductive components and assemblies is an integral part of the product life cycle of almost every technical product in our daily life. Particularly in the automotive and aerospace industry, the use of modern light-weight materials allows the development of ever more powerful and efficient mechanical structures. These heavy duty components must be tested for their structural integrity in the production phase as well as in the subsequent operating phase in order to ensure safe and reliable operation. Lorentz force eddy current testing (LET), which is investigated in this work, is one of the testing methods that are capable to meet the growing requirements of these industries. The thesis begins with a brief introduction into the state-of-the-art in NDT and a presentation of the involved industrial markets. Subsequently, the related work in the field of motion-induced eddy current testing methods is described. A particular focus is on the experimental investigations carried out in previous feasibility studies. The consideration of the physical phenomena relevant to the measuring principle, by means of the dimensional analysis, allows a deepening insight into the interactions of the electromagnetic and geometric parameters. A comprehensive numerical study accompanies this study and leads to the elaboration of practical scaling laws. The most comprehensive part of the thesis is the classification and the systematic description of the measurement procedure of LET and a representative overview of the measurement performance of the developed experimental setup. In this study, a novel multi-component sensor system is used, which allows simultaneous recording of the occurring measuring forces as well as their accelerating effect on the measurement setup. The idealized (deterministic) measurement process is extended to a real measurement process by considering the involved physical quantities as random variables. It is analyzed that the statistical properties of the measurement result, e.g. mean and variance of a physical quantity, are not independent of time. Thus, a measurement signal of a single measurement cannot provide a complete measurement result for the non-stationary measurement process. Therefore, the assembling of an artificial signal ensemble of sequential measurements is suggested, which for the first time enables the calculation of complete measurement results in LET. The mechanical modeling of the dynamics of the experimental setup is another novelty in the theoretical description of LET measurement process. For this purpose, the process of system identification is presented exemplary for two practically relevant examples. This allows a straight modeling of the mechanical system by an appropriate signal preprocessing and a model-specific parameter estimation. Based on these mechanical models, the design process of digital filters is shown in order to compensate the frequency-dependent sensitivity of the applied force sensor.Die zerstörungsfreie Materialprüfung elektrisch leitfähiger Komponenten und Baugruppen ist ein integraler Bestandteil im Produktlebenszyklus heutiger technischer Produkte. Insbesondere im Automobilbau sowie der Luft- und Raumfahrttechnik ist durch den Einsatz moderner Leichtbaumaterialien die Entwicklung immer leistungsfähigere mechanischer Komponenten möglich. Diese hochbeanspruchbaren Bauteile müssen sowohl in der Fertigungsphase als auch in der späteren Betriebsphase auf ihre strukturelle Integrität geprüft werden, um einen sicheren und zuverlässigen Betrieb gewährleisten zu können. Die in dieser Arbeit untersuchte Lorentzkraft-Wirbelstromprüfung ist eines der Prüfverfahren, welche in diesem Zusammenhang erforscht und weiterentwickelt werden. Nach einer kurzen Einführung in den Stand der Technik der zerstörungsfreien Materialprüfung und einer Vorstellung der relevanten Märkte, werden die vorangegangen Arbeiten auf dem Gebiet der bewegungsinduzierten Wirbelstromprüfverfahren beleuchtet. Ein besonderes Augenmerk liegt dabei auf den experimentellen Untersuchungen, welche in vorangegangenen Machbarkeitsstudien erfolgreich durchgeführt wurden. Die Betrachtung der für das Messprinzip relevanten physikalischen Phänomene ermöglicht mittels der durchgeführten Dimensionsanalyse einen vertiefenden Einblick in die Wechselwirkungen der elektromagnetischen und geometrischen Größen. Umfassende numerische Studien begleiten diese Untersuchung und führen zur Formulierung von praktischen Skalierungsregeln. Den umfassendsten Teil der Arbeit bilden die Klassifizierung und die systematische Beschreibung des untersuchten Messverfahrens, sowie die repräsentative Darstellung experimenteller Studien. Hierbei kommt ein mehrkomponentiges Sensorsystem zum Einsatz, welches die zeitgleiche Erfassung der auftretenden Messkräfte sowie deren Beschleunigungswirkung auf den Messaufbau ermöglicht. Das idealisierte Messverfahren wird durch die Betrachtung der beteiligten physikalischen Größen als Zufallsvariablen zu einem realen Messprozess erweitert. Dabei zeigt sich, dass die statistischen Eigenschaften des Messprozesses nicht zeitunabhängig sind und somit ein Messsignal einer einzelnen Messung kein vollständiges Messergebnis, im Sinne einer experimentellen Standardabweichung, liefern kann. Aus dieser Einsicht heraus werden Ansätze für die Bildung von künstlichen Signalscharen beschrieben und in unterschiedlichen experimentellen Studien erprobt. Diese Signalensembles, welche aus Einzelsignalen bestehen, ermöglichen dabei erstmals eine statistische Auswertung der Messergebnisse. Einen Neuheitswert stellt ebenfalls die in der Arbeit vorgestellte Erweiterung des Messmodells zu einem nicht rückwirkungsfreien Messverfahren dar, welches die mechanische Wechselwirkung der Lorentzkraft und des mechanischen Messaufbaus beschreibt. Hierfür werden für zwei praktisch relevante Beispiele geeignete Verfahren zur Systemidentifikation vorgestellt, welche sowohl in der Signalvorverarbeitung als auch der modellspezifischen Parameterschätzung eine einfache Modellbildung des mechanischen Systems ermöglichen. Aus den so gewonnenen mechanischen Modellen wird anschließend beispielhaft der Entwurf digitaler Filter zur Kompensation des frequenzabhängigen Übertragungsverhaltens dargestellt

    Rheology and structure of foams

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