Global ETD Search

41	Odhad dechové frekvence z elektrokardiogramu a fotopletysmogramu / Breathing Rate Estimation from the Electrocardiogram and Photoplethysmogram Janáková, Jaroslava January 2021 (has links) The master thesis deals with the issue of gaining the respiratory rate from ECG and PPG signals, which are not only in clinical practice widely used measurable signals. The theoretical part of the work outlines the issue of obtaining a breath curve from these signals. The practical part of the work is focused on the implementation of five selected methods and their final evaluation and comparison.
42	Navigating the "ACM" Digital Library with a new Visualization Interface Cheenath, Jackson Jacob 17 July 2013 (has links) No description available. Information Technology Information Systems Computer Science Design Digital Library Digital Library Navigation Digital Library Visualization Visual interface for Digital Library ACM Digital Library Visual Navigation Phrase Extraction Citeology Navigating the ACM Digital Library Extracting Meaningful Data EMD ACM
43	Analysis of Long-Term Utah Temperature Trends Using Hilbert-Haung Transforms Hargis, Brent H 01 June 2014 (has links) (PDF) We analyzed long-term temperature trends in Utah using a relatively new signal processing method called Empirical Mode Decomposition (EMD). We evaluated the available weather records in Utah and selected 52 stations, which had records longer than 60 years, for analysis. We analyzed daily temperature data, both minimum and maximums, using the EMD method that decomposes non-stationary data (data with a trend) into periodic components and the underlying trend. Most decomposition algorithms require stationary data (no trend) with constant periods and temperature data do not meet these constraints. In addition to identifying the long-term trend, we also identified other periodic processes in the data. While the immediate goal of this research is to characterize long-term temperature trends and identify periodic processes and anomalies, these techniques can be applied to any time series data to characterize trends and identify anomalies. For example, this approach could be used to evaluate flow data in a river to separate the effects of dams or other regulatory structures from natural flow or to look at other water quality data over time to characterize the underlying trends and identify anomalies, and also identify periodic fluctuations in the data. If these periodic fluctuations can be associated with physical processes, the causes or drivers might be discovered helping to better understand the system. We used EMD to separate and analyze long-term temperature trends. This provides awareness and support to better evaluate the extremities of climate change. Using these methods we will be able to define many new aspects of nonlinear and nonstationary data. This research was successful and identified several areas in which it could be extended including data reconstruction for time periods missing data. This analysis tool can be applied to various other time series records. Hilbert HHT Hilbert Haung Hilbert Haung Transforms Statistics Time Series Weather Stations Transforms Signal Analysis Fourier Transforms Wavelet Transforms Multivariate Analysis Climatological Intrinsic Mode Function Empirical Mode Decomposition IMF EMD Instantaneous Phase Instantaneous Frequency Residue Civil and Environmental Engineering
44	Mathematical modelling of primary alkaline batteries Johansen, Jonathan Frederick January 2007 (has links) Three mathematical models, two of primary alkaline battery cathode discharge, and one of primary alkaline battery discharge, are developed, presented, solved and investigated in this thesis. The primary aim of this work is to improve our understanding of the complex, interrelated and nonlinear processes that occur within primary alkaline batteries during discharge. We use perturbation techniques and Laplace transforms to analyse and simplify an existing model of primary alkaline battery cathode under galvanostatic discharge. The process highlights key phenomena, and removes those phenomena that have very little effect on discharge from the model. We find that electrolyte variation within Electrolytic Manganese Dioxide (EMD) particles is negligible, but proton diffusion within EMD crystals is important. The simplification process results in a significant reduction in the number of model equations, and greatly decreases the computational overhead of the numerical simulation software. In addition, the model results based on this simplified framework compare well with available experimental data. The second model of the primary alkaline battery cathode discharge simulates step potential electrochemical spectroscopy discharges, and is used to improve our understanding of the multi-reaction nature of the reduction of EMD. We find that a single-reaction framework is able to simulate multi-reaction behaviour through the use of a nonlinear ion-ion interaction term. The third model simulates the full primary alkaline battery system, and accounts for the precipitation of zinc oxide within the separator (and other regions), and subsequent internal short circuit through this phase. It was found that an internal short circuit is created at the beginning of discharge, and this self-discharge may be exacerbated by discharging the cell intermittently. We find that using a thicker separator paper is a very effective way of minimising self-discharge behaviour. The equations describing the three models are solved numerically in MATLABR, using three pieces of numerical simulation software. They provide a flexible and powerful set of primary alkaline battery discharge prediction tools, that leverage the simplified model framework, allowing them to be easily run on a desktop PC. advection anode asymptotic analysis BET surface area binary electrolyte boundary condition Butler-Volmer equation cathode closed circuit voltage concentration polarisation control volume current path discretisation diffusion electrochemical reaction electrode electrolytic manganese dioxide EMD crystals EMD particles exchange current density geometric surface area initial condition linearisation macrohomogeneous porous electrode theory mathematical model Nernst equation ohmic losses open circuit voltage ordinary differential equation overpotential partial differential equation perturbation techniques potassium hydroxide potassium zincate precipitation reaction primary battery separator paper simulation ternary electrolyte theoretical capacity utilisation zinc zinc oxide
45	Αναγνώριση βασικών κινήσεων του χεριού με χρήση ηλεκτρομυογραφήματος / Recognition of basic hand movements using electromyography Σαψάνης, Χρήστος 13 October 2013 (has links) Ο στόχος αυτής της εργασίας ήταν η αναγνώριση έξι βασικών κινήσεων του χεριού με χρήση δύο συστημάτων. Όντας θέμα διεπιστημονικού επιπέδου έγινε μελέτη της ανατομίας των μυών του πήχη, των βιοσημάτων, της μεθόδου της ηλεκτρομυογραφίας (ΗΜΓ) και μεθόδων αναγνώρισης προτύπων. Παράλληλα, το σήμα περιείχε αρκετό θόρυβο και έπρεπε να αναλυθεί, με χρήση του EMD, να εξαχθούν χαρακτηριστικά αλλά και να μειωθεί η διαστασιμότητά τους, με χρήση των RELIEF και PCA, για βελτίωση του ποσοστού επιτυχίας ταξινόμησης. Στο πρώτο μέρος γίνεται χρήση συστήματος ΗΜΓ της Delsys αρχικά σε ένα άτομο και στη συνέχεια σε έξι άτομα με το κατά μέσο όρο επιτυχημένης ταξινόμησης, για τις έξι αυτές κινήσεις, να αγγίζει ποσοστά άνω του 80%. Το δεύτερο μέρος περιλαμβάνει την κατασκευή αυτόνομου συστήματος ΗΜΓ με χρήση του Arduino μικροελεγκτή, αισθητήρων ΗΜΓ και ηλεκτροδίων, τα οποία είναι τοποθετημένα σε ένα ελαστικό γάντι. Τα αποτελέσματα ταξινόμησης σε αυτή την περίπτωση αγγίζουν το 75%. / The aim of this work was to identify six basic movements of the hand using two systems. Being an interdisciplinary topic, there has been conducted studying in the anatomy of forearm muscles, biosignals, the method of electromyography (EMG) and methods of pattern recognition. Moreover, the signal contained enough noise and had to be analyzed, using EMD, to extract features and to reduce its dimensionality, using RELIEF and PCA, to improve the success rate of classification. The first part uses an EMG system of Delsys initially for an individual and then for six people with the average successful classification, for these six movements at rates of over 80%. The second part involves the construction of an autonomous system EMG using an Arduino microcontroller, EMG sensors and electrodes, which are arranged in an elastic glove. Classification results in this case reached 75% of success. RELIEF αλγόριθμος Αναγνώριση προτύπων 612.76 Biomedical signal analysis RELIEF algorithm Empirical Mode Decomposition (EMD) Principal Component Analysis (PCA) Pattern recognition Arduino Support Vector Machines (SVM) K - nearest neighbor (KNN) Feature selection Electromyography (EMG)
46	Développement de méthodes de séparation des nombres d'onde acoustiques et convectifs en écoulements turbulents pariétaux Debert, Sébastien 18 December 2008 (has links) (PDF) Ce travail a pour but le développement de techniques de séparation des contributions acoustique et aérodynamique de champs de pression pariétale sous des écoulements turbulents. Ces techniques de séparation, dites en nombre d'onde, se basent sur les propriétés spatiales de ces fluctuations. La compréhension des phénomènes de chacun des deux types fluctuations de pression pariétale s'exerçant sur la vitre latérale d'un véhicule vient servir un enjeu industriel de réduction du niveau sonore intérieur du bruit de forme des automobiles. Pour ce faire, des expérimentations en soufflerie anéchoïque sont menées afin d'obtenir des mesures de pression pariétale fluctuante pour divers types d'écoulements. Ainsi un écoulement de couche limite turbulente pleinement développée sur plaque plane, des écoulements décollés en aval de trois géométries de marches montantes, ainsi qu'en aval d'un montant de baie sur véhicule réel sont considérés. Une représentation des spectres en nombre d'onde-fréquence (obtenue par la méthode du corrélogramme spatial) est choisie pour séparer les deux contributions. Cette technique ne s'appliquant que sur des écoulements stationnaires et homogènes, de nouvelles techniques basées sur la Décomposition Modale Empirique (EMD) sont utilisées, d'une part pour améliorer la séparation des deux contributions (grâce à l'EMD spatiale), d'autre part pour obtenir une décomposition multi-échelle au cours du temps (grâce à l'Ensemble-EMD). Grâce à ces méthodes, une observation plus précise des phénomènes pariétaux convectifs et acoustiques est proposée. Aéroacoustique Spectre en nombre d'onde Décomposition Modale Empirique (EMD) Traitement du signal Bruit de Couche Limite Bruit Aérodynamique Couche Limite Turbulente Ecoulements turbulents décollés
47	Analyse des signaux non-stationnaires par transformation de Huang, Opérateur deTeager-Kaiser, et Transformation de Huang-Teager (THT) Cexus, Jean-Christophe 12 December 2005 (has links) (PDF) L'objectif repose sur le traitement et l'analyse des signaux non-stationnaires, multi-composantes. <br />Pour le traitement (filtrage et débruitage), nous proposons de nouveaux outils fondés sur la Transformation de Huang (ou Décomposition modale empirique : EMD). Partant de l'opérateur de Teager-Kaiser, nous proposons un nouvel opérateur de mesure d'interaction entre deux signaux complexes. Nous établissons les liens théoriques avec les représentations temps-fréquence de la classe de Cohen. Nous montrons que c'est une mesure de similarité et qu'il est adapté à la détection de signaux. <br />Pour l'analyse, nous introduisons une nouvelle méthode temps-fréquence basée sur l'utilisation conjointe de l'EMD et de l'opérateur de Teager-Kaiser : la Transformation de Huang-Teager (THT). Pour illustrer ces concepts, des résultats de filtrage, de débruitage, de détection, d'analyse temps-fréquence de signaux sont présentés. Nous terminons par l'analyse et classification des échos de cibles sonars par THT. Analyse temps-fréquence Signal multi-composantes Signal non-stationnaire Empirical mode decomposition (EMD) opérateur (croisée) de Teager-Kaiser Transformation de Huang-Teager (THT) Fréquence instantanée détection débruitage classification de signaux
48	Predictability of Nonstationary Time Series using Wavelet and Empirical Mode Decomposition Based ARMA Models Lanka, Karthikeyan January 2013 (has links) (PDF) The idea of time series forecasting techniques is that the past has certain information about future. So, the question of how the information is encoded in the past can be interpreted and later used to extrapolate events of future constitute the crux of time series analysis and forecasting. Several methods such as qualitative techniques (e.g., Delphi method), causal techniques (e.g., least squares regression), quantitative techniques (e.g., smoothing method, time series models) have been developed in the past in which the concept lies in establishing a model either theoretically or mathematically from past observations and estimate future from it. Of all the models, time series methods such as autoregressive moving average (ARMA) process have gained popularity because of their simplicity in implementation and accuracy in obtaining forecasts. But, these models were formulated based on certain properties that a time series is assumed to possess. Classical decomposition techniques were developed to supplement the requirements of time series models. These methods try to define a time series in terms of simple patterns called trend, cyclical and seasonal patterns along with noise. So, the idea of decomposing a time series into component patterns, later modeling each component using forecasting processes and finally combining the component forecasts to obtain actual time series predictions yielded superior performance over standard forecasting techniques. All these methods involve basic principle of moving average computation. But, the developed classical decomposition methods are disadvantageous in terms of containing fixed number of components for any time series, data independent decompositions. During moving average computation, edges of time series might not get modeled properly which affects long range forecasting. So, these issues are to be addressed by more efficient and advanced decomposition techniques such as Wavelets and Empirical Mode Decomposition (EMD). Wavelets and EMD are some of the most innovative concepts considered in time series analysis and are focused on processing nonlinear and nonstationary time series. Hence, this research has been undertaken to ascertain the predictability of nonstationary time series using wavelet and Empirical Mode Decomposition (EMD) based ARMA models. The development of wavelets has been made based on concepts of Fourier analysis and Window Fourier Transform. In accordance with this, initially, the necessity of involving the advent of wavelets has been presented. This is followed by the discussion regarding the advantages that are provided by wavelets. Primarily, the wavelets were defined in the sense of continuous time series. Later, in order to match the real world requirements, wavelets analysis has been defined in discrete scenario which is called as Discrete Wavelet Transform (DWT). The current thesis utilized DWT for performing time series decomposition. The detailed discussion regarding the theory behind time series decomposition is presented in the thesis. This is followed by description regarding mathematical viewpoint of time series decomposition using DWT, which involves decomposition algorithm. EMD also comes under same class as wavelets in the consequence of time series decomposition. EMD is developed out of the fact that most of the time series in nature contain multiple frequencies leading to existence of different scales simultaneously. This method, when compared to standard Fourier analysis and wavelet algorithms, has greater scope of adaptation in processing various nonstationary time series. The method involves decomposing any complicated time series into a very small number of finite empirical modes (IMFs-Intrinsic Mode Functions), where each mode contains information of the original time series. The algorithm of time series decomposition using EMD is presented post conceptual elucidation in the current thesis. Later, the proposed time series forecasting algorithm that couples EMD and ARMA model is presented that even considers the number of time steps ahead of which forecasting needs to be performed. In order to test the methodologies of wavelet and EMD based algorithms for prediction of time series with non stationarity, series of streamflow data from USA and rainfall data from India are used in the study. Four non-stationary streamflow sites (USGS data resources) of monthly total volumes and two non-stationary gridded rainfall sites (IMD) of monthly total rainfall are considered for the study. The predictability by the proposed algorithm is checked in two scenarios, first being six months ahead forecast and the second being twelve months ahead forecast. Normalized Root Mean Square Error (NRMSE) and Nash Sutcliffe Efficiency Index (Ef) are considered to evaluate the performance of the proposed techniques. Based on the performance measures, the results indicate that wavelet based analyses generate good variations in the case of six months ahead forecast maintaining harmony with the observed values at most of the sites. Although the methods are observed to capture the minima of the time series effectively both in the case of six and twelve months ahead predictions, better forecasts are obtained with wavelet based method over EMD based method in the case of twelve months ahead predictions. It is therefore inferred that wavelet based method has better prediction capabilities over EMD based method despite some of the limitations of time series methods and the manner in which decomposition takes place. Finally, the study concludes that the wavelet based time series algorithm could be used to model events such as droughts with reasonable accuracy. Also, some modifications that could be made in the model have been suggested which can extend the scope of applicability to other areas in the field of hydrology. Time Series Forecasting Nonstationary Time Series Wavelets Time Series Decomposition Algorithms Autoregressive Moving Average Model Time Series Modeling Time Series Analysis Streamflow Rain and Rainfall Time Series Nonstationarity Drought Forecasting Hydrology - Time Series Modeling Empirical Mode Decomposition Model Continuous Wavelet Transforms (CWT) Time Series Forecasting Techniques Discrete Wavelet Transform (DWT) Empirical Mode Decomposition (EMD) Civil Engineering
49	Décomposition Modale Empirique : Contribution à la Modélisation Mathématique et Application en Traitement du Signal et de l'Image Niang, Oumar 20 September 2007 (has links) (PDF) La Décomposition Modale Empirique (EMD), est une méthode de décomposition multi-résolution de signaux en fonctions Modes Intrinsèques (IMF) et cela, de manière auto-adaptative. En la couplant avec la transformée de Hilbert, elle devient une méthode d'analyse Temps-Fréquence , la transformée de Hilbert-Huang, permettant d'étudier bon nombre de classes de signaux. Malgré ces nombreuses applications, l'une des plus importantes limites de l'EMD est son manque de formalisme mathématique. A la place d'une interpolation par splines cubiques utilisée dans l'EMD classique, nous avons estimé l'enveloppe moyenne par une solution d'un système d'EDP. Par une méthode variationnelle, nous avons établi un cadre théorique pour prouver les résultats de convergence, d'existence de modes et la propriété de presque orthogonalité de l'EMD. La comparaison avec des bancs de filtres itératifs et les ondelettes, montre l'aspect multi-résolution de l'EMD. Deux nouvelles applications en traitement du signal et de l'image sont présentées : l'extraction des intermittences et mode mixing et la restauration par shrinkage par EMD. Enfin le modèle peut servir de base pour l'étude de l'unicité de la décomposition. Décomposition Modale Empirique Modélisation mathématique Équations aux Dérivées Partielles Interpolation Enveloppe moyenne Analyse Temps-Fréquence Analyse Multi-résolution Ondelettes Algorithme de Poursuite Banc de Filtres Analyse d'Images Points Caractéristiques Méthodes Spectrales Régularisation de Tikhonov shrinkage par ondelettes shrinkage par EMD Inpainting
50	Legal and regulatory aspects of mobile financial services Perlman, Leon Joseph 11 1900 (has links) The thesis deals with the emergence of bank and non-bank entities that provide a range of unique transaction-based payment services broadly called Mobile Financial Services (MFS) to unbanked, underserved and underbanked persons via mobile phones. Models of MFS from Mobile Network Operators (MNOs), banks, combinations of MNOs and banks, and independent Mobile Financial Services Providers are covered. Provision by non-banks of ‘bank-type’ services via mobile phones has been termed ‘transformational banking’ versus the ‘additive banking’ services from banks. All involve the concept of ‘branchless banking’ whereby ‘cash-in/cash out’ services are provided through ‘agents.’ Funds for MFS payments may available through a Stored Value Product (SVP), particularly through a Stored Value Account SVP variant offered by MNOs where value is stored as a redeemable fiat- or mobile ‘airtime’-based Store of Value. The competitive, legal, technical and regulatory nature of non-bank versus bank MFS models is discussed, in particular the impact of banking, payments, money laundering, telecommunications, e-commerce and consumer protection laws. Whether funding mechanisms for SVPs may amount to deposit-taking such that entities could be engaged in the ‘business of banking’ is discussed. The continued use of ‘deposit’ as the traditional trigger for the ‘business of banking’ is investigated, alongside whether transaction and paymentcentric MFS rises to the ‘business of banking.’ An extensive evaluation of ‘money’ based on the Orthodox and Claim School economic theories is undertaken in relation to SVPs used in MFS, their legal associations and import, and whether they may be deemed ‘money’ in law. Consumer protection for MFS and payments generally through current statute, contract, and payment law and common law condictiones are found to be wanting. Possible regulatory arbitrage in relation to MFS in South African law is discussed. The legal and regulatory regimes in the European Union, Kenya and the United States of America are compared with South Africa. The need for a coordinated payments-specific law that has consumer protections, enables proportional risk-based licensing of new non-bank providers of MFS, and allows for a regulator for retail payments is recommended. The use of trust companies and trust accounts is recommended for protection of user funds. \| vi / Public, Constitutional and International Law / LLD Agents Airtime transfer Airtime -based SOV Allocation of loss Allocation of risk Anti-Money Laundering (AML) Aristotle Australian school Auto-subscription Banks Banks Act Bilateral Juristic Act Bottom of Pyramid Branchless Banking BSD Business of banking Cash-In /Cash out Central Bank Claim school Competition Commission Condictiones Consumer protection Consumer Protection Act (CPA) Contract law Convergence CTF Dedicated Banks Bill Delict Regulatory philosophies Deposits Deposit-taking Directives Dodd-Frank Electronic Commerce (e-commerce) Electronic Funds Transfer (EFT) Electronic money (e-money) Electronic Money Directive (EMD) European Union (EU) FA Mann Fiat Fiat-based SOV FICA Financial inclusion Financial literacy Foley v Hill Hacking ICASA Kenya KYC Legal capacity m-Banking Means of exchange Means of payment MFS MFSP Miller v Race Minors MNO Mobile Banking (m-Banking Mobile Commerce (m-commerce) Mobile Financial Services (MFS) Mobile Financial Service Provider (MFSP) Mobile Financial Services Provide (MFSP) Mobile Network Operator (MNO) Mobile payments Mobile payments (m-Payments) Mobile purse Mobile wallet Money Money Laundering (ML) m-Payments m-pesa National Consumer Commission National Payment System National Payment System Act (NPSA) Non-Banks NPSA Orthodox school Oversight Payment instrument Payments law Pooled accounts Position paper Proportional regulation Prudential Regulation PSD PSPL PSRA Redeemable funds Regulator's dilemma Regulatory capture Remittances (RICA) (South Africa) Security SIM Card SIPS South African Reserve Bank SOV Specie Store of Value (SOV) Stored Value Account (SVA) Subscriber Supervison Systemic risk Telecommunications Transformational banking Trust accounts Unbanked Underserved Underbanked Unit of account United Dominions Trust (UDT) Unjustified enrichment USA Value Added Services (VAS) Wallet WASP WASPA Additive banking Regulatory arbitrage 346.82120680285 Banks and banking, mobile --South Africa

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