940 research outputs found

    Advances in Character Recognition

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    This book presents advances in character recognition, and it consists of 12 chapters that cover wide range of topics on different aspects of character recognition. Hopefully, this book will serve as a reference source for academic research, for professionals working in the character recognition field and for all interested in the subject

    Character Recognition

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    Character recognition is one of the pattern recognition technologies that are most widely used in practical applications. This book presents recent advances that are relevant to character recognition, from technical topics such as image processing, feature extraction or classification, to new applications including human-computer interfaces. The goal of this book is to provide a reference source for academic research and for professionals working in the character recognition field

    Biometric Systems

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    Biometric authentication has been widely used for access control and security systems over the past few years. The purpose of this book is to provide the readers with life cycle of different biometric authentication systems from their design and development to qualification and final application. The major systems discussed in this book include fingerprint identification, face recognition, iris segmentation and classification, signature verification and other miscellaneous systems which describe management policies of biometrics, reliability measures, pressure based typing and signature verification, bio-chemical systems and behavioral characteristics. In summary, this book provides the students and the researchers with different approaches to develop biometric authentication systems and at the same time includes state-of-the-art approaches in their design and development. The approaches have been thoroughly tested on standard databases and in real world applications

    Estimation of load sharing among muscles acting on the same joint and Applications of surface electromyography

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    The force produced by a specific muscle cannot be measured and what is measured is the total force provided by all the active muscles acting on a joint, including agonists and antagonists. The first part of this work (chapter 3) addresses the issue of load sharing by proposing two possible approaches and testing them. The second part (chapter 4 and 5) addresses two applications of surface EMG focusing on the study of a) muscle relaxation associated to Yoga sessions and b) the activation of muscle of the back and shoulder of musicians playing string instruments (violin, viola and cello). In both parts the element of innovation is the use of two dimensional electrode arrays and of techniques based on EMG Imaging. The objectives of this work are presented and explained in chapter 1 while the basic concepts of surface EMG are summarized in chapter 2. Different EMG-based muscle force models found in the literature are explained and discussed. Two renowned amplitude indicators in surface EMG (sEMG) studies are the average rectified value (ARV) and the root mean square (RMS). These two amplitude indicators are computed over a defined time window of the recorded signals to represent the muscle activity. The advantages and disadvantages of RMS and ARV are compared and discussed for a simple sinusoid as well as for more complex signals (simulated motor unit action potential detected by high density electrode grid). The results show that RMS is more robust to the sampling frequency than ARV. In this thesis, starting from the simulation of a single fiber and of a group of fibers (motor unit), it is shown that inter electrode distance (IED) greater than10 mm causes aliasing. Aliasing is a source of error in sEMG map interpretation or decisions that are made by automatic algorithms such as those providing image segmentation for the identifications of regions of interest. Chapter 2 discusses three segmentation algorithms (K-means, h-dome, watershed) and compares them in order to find the most suitable method. Results reveal that among the three mentioned algorithms, watershed provides most accurate segmentation for the simulated ARV maps. Chapter 3 presents a mathematical model that is associated to the monotonic Force-EMG relation. A possible non-linear relationship between the EMG and force or torque is presented. A system of "M" equations is obtained by performing "M" measurements at "M" different force levels in isometric conditions. The solutions of such system of equations are the values for each muscles. Two different approaches were investigated for finding the solutions of the system, which are: a) Analytical-Graphical Approach (AGA) and b) Numerical Approach (NA) consisting of error minimization (between the total estimated and measured force) applying optimization algorithms. The AGA was used to find the model parameters of each muscle contributing to the force production on a joint by finding the intersection of those surfaces that can be obtained from sequential substitutions of the model parameters in the equations corresponding to each contraction level. In simulation studies, the AGA graphically shows that there is more than one solution to the load sharing problem even for the simplest theoretical case (i.e. a joint spanned by only two muscles). The second approach, based on minimization of the mean square error between the measured and the total estimated force or torque (with "N" muscles involved) provides an estimate of the model parameters that in turn provides the force contributions of the individual muscles. The optimization algorithms can find the solutions of our system made of non-linear equations (see chapter 3). Starting from different point (initial conditions), different solutions can be found, as predicted by the AGA approach for the two-muscle case. The main conclusion of this study is that the load sharing strategy is not unique. Chapter 4 discusses the application of surface electromyography to a single case study of Yoga relaxation to show the feasibility of measurements. The effect of yoga relaxation on muscle activity (sEMG amplitude), as well as on mean and median frequencies and muscle fiber's conduction Velocity, is discussed in this chapter. No changes in the sEMG activity pattern distribution were found for the same task performed before and after applying yoga relaxation technique. However, myoelectric manifestations of fatigue were smaller after relaxation and returned to the normal pattern after the recovery phase from relaxation. Further studies are justified. Chapter 5 describes results and discusses the spatial distribution of muscle activity over the Trapezius and Erector Spinae muscles of musicians playing string instruments. In chapter 5, the effect of backrest support in sitting position during playing cello, viola, and violin on the muscle activity index of upper and lower Trapezius muscle of the bowing arm, upper Trapezius muscle of non-bowing arm, left and right Erector Spinae muscles is investigated. Two professional players (one cello and one viola) and five student players (one cello, three violin and one viola) participated in this study. The muscle activity index (MAI) was defined as the spatial average of RMS values of the muscle active region detected by watershed segmentation for Trapezius muscles (left and right), and thresholding technique (70% of the maximum value) for left and right Erector Spinae muscles. It was found that the MAI is string (note) dependent. Statistical difference (p < 0:05) between the MAIs of left Erector Spinae muscle during playing with and without backrest support was observed in four (out of five) student players. No statistical differences were observed on the muscle activity of Trapezius (bowing and no-bowing arms) during playing with and without backrest support in different types of bowing for all musicians. In conclusion, this work addresses a) the issue of spatial sampling and segmentation of sEMG using 2D electrode arrays, b) two possible approaches to the load-sharing issue, c) a single-case study of Yoga relaxation and d) the distribution of muscle activity above the Trapezius and Erector Spinae muscles of musicians playing string instruments. Previously unavailable knowledge has been achieved in all these four studies

    Identifying Phonological Awareness ?Outcomes in a Personal Setting

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    The focus of this project was to create a procedures guide containing research-supported lessons that facilitate the acquisition of phonological awareness by students in a preschool or kindergarten classroom. An investigation of the related literature revealed aspects of phonological awareness that can be taught to preliterate children before the onset of formal training. The product of this investigation is a guide containing lessons and activities either extracted from or modeled after those field tested in many classrooms

    Machine learning approaches to video activity recognition: from computer vision to signal processing

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    244 p.La investigación presentada se centra en técnicas de clasificación para dos tareas diferentes, aunque relacionadas, de tal forma que la segunda puede ser considerada parte de la primera: el reconocimiento de acciones humanas en vídeos y el reconocimiento de lengua de signos.En la primera parte, la hipótesis de partida es que la transformación de las señales de un vídeo mediante el algoritmo de Patrones Espaciales Comunes (CSP por sus siglas en inglés, comúnmente utilizado en sistemas de Electroencefalografía) puede dar lugar a nuevas características que serán útiles para la posterior clasificación de los vídeos mediante clasificadores supervisados. Se han realizado diferentes experimentos en varias bases de datos, incluyendo una creada durante esta investigación desde el punto de vista de un robot humanoide, con la intención de implementar el sistema de reconocimiento desarrollado para mejorar la interacción humano-robot.En la segunda parte, las técnicas desarrolladas anteriormente se han aplicado al reconocimiento de lengua de signos, pero además de ello se propone un método basado en la descomposición de los signos para realizar el reconocimiento de los mismos, añadiendo la posibilidad de una mejor explicabilidad. El objetivo final es desarrollar un tutor de lengua de signos capaz de guiar a los usuarios en el proceso de aprendizaje, dándoles a conocer los errores que cometen y el motivo de dichos errores

    Dictionary of Invertebrate Zoology

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    An exhaustive dictionary of over 13,000 terms relating to invertebrate zoology, including etymologies, word derivations and taxonomic classification. Entries cover parasitology, nematology, marine invertebrates, insects, and anatomy, biology, and reproductive processes for the following phyla: Acanthocephala Annelida Arthropoda Brachiopoda Bryozoa Chaetognatha Cnidaria Ctenophora Echinodermata Echiura Entoprocta Gastrotricha Gnathostomulida Kinorhyncha Loricifera Mesozoa Mollusca Nemata Nematomorpha Nemertea Onychophora Pentastoma Phoronida Placozoa Platyhelminthes Pogonophora Porifera Priapula Rotifera Sipuncula Tardigrada.https://digitalcommons.unl.edu/zeabook/1061/thumbnail.jp

    Drawing, Handwriting Processing Analysis: New Advances and Challenges

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    International audienceDrawing and handwriting are communicational skills that are fundamental in geopolitical, ideological and technological evolutions of all time. drawingand handwriting are still useful in defining innovative applications in numerous fields. In this regard, researchers have to solve new problems like those related to the manner in which drawing and handwriting become an efficient way to command various connected objects; or to validate graphomotor skills as evident and objective sources of data useful in the study of human beings, their capabilities and their limits from birth to decline

    On the embryonic and post-embryonic development of Pseudopallene sp. (Arthropoda, Pycnogonida) with special focus on neurogenesis and nervous system differentiation

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    Diese Arbeit befasst sich mit der Entwicklung der Asselspinne Pseudopallene sp. (Arthropoda, Pycnogonida). Die Morphogenese und Nervensystementwicklung werden mithilfe von Rasterelektronenmikroskopie, Histologie, Immunhistochemie und Genexpressionsstudien untersucht. Während der Proboscisbildung lassen sich keine Anzeichen für ein Labrum erkennen. Aufgrund des Fehlens von Palpen- und Ovigeranlagen und der frühen Entwicklung der Laufbeinsegmente ist kein embryonales Protonymphon-Stadium identifizierbar. Die Evolution verschiedener Larvenformen der Pycnogoniden wird im Hinblick auf phylogenetische Studien diskutiert. Die frühen Prozesse im Neuroektoderm zeigen Ähnlichkeiten zu Eucheliceraten und Myriapoden. Hierzu zählen das Fehlen morphologisch distinkter Zelltypen, die Bildung von Zellinternalisierungszentren, die Immigration vorwiegend post-mitotischer Ganglionzellen mit erhöhter Delta-Genexpression und fast ausschließlich tangentiale Zellteilungen. Anschließend bilden sich pro Neuromer ein Paar Invaginationen, was durch Vergrößerung der apikalen Zellen begleitet wird. Letztere sind aufgrund ihrer hohen Mitoseaktivität, ihres asymmetrischen Teilungsmodus und des anhaltenden Zuwachses der basalen Ganglionzellen als stammzellartige neuronale Vorläuferzellen identifizierbar. Hierauf basierend wird die Validität von stammzellartigen neuronalen Vorläuferzellen als Synapomorphie der Krebse und Insekten diskutiert. Zwei evolutionäre Szenarien zur Arthropoden-Neurogenese werden erörtert. In der post-embryonalen Phase lösen sich die invaginierten Zellregionen vom Ektoderm ab. Sie bilden apikal auf den Ganglien paarige Zellcluster und bleiben mit deren Somacortex über fibrilläre ‚cell streams‘ verbunden. Der weitere Zuwachs an Ganglionzellen und die exklusive Zellproliferation in den cluster-stream-Systemen weisen letztere als post-embryonale neurogenetische Nischen aus. Ähnlichkeiten zu der neurogenetischen Nische im Deutocerebrum der decapoden Krebse werden aufgezeigt.This study addresses aspects of the development of the sea spider Pseudopallene sp. (Arthropoda, Pycnogonida). In order to investigate morphogenesis and nervous system development, a combination of scanning electron microscopy, histology, immunohistochemistry and gene expression studies is used. Embryonic proboscis development shows no signs of a labrum. The lack of palpal and ovigeral limbs and the early anlagen of the walking leg segments lead to the rejection of an embryonized protonymphon stage during Pseudopallene development. The evolution of pycnogonid hatching stages is evaluated in light of recent phylogenetic analyses. Early neurogenesis shares similarities with euchelicerates and myriapods, including the lack of morphologically distinct neuroectodermal cell types, formation of transient cell internalization sites, immigration of mostly post-mitotic ganglion cells with elevated levels of Delta gene expression and predominantly tangentially oriented cell divisions in the neuroectoderm. Subsequently, paired invaginations form in each neuromere, being accompanied by marked enlargement of the apical cells. Due to their high mitotic activity, their asymmetric division mode and a marked cell number increase in the ganglia, the big cells are identified as stem cell-like neuronal precursors. Based on this, the validity of stem cell-like neuronal precursors as synapomorphy of crustaceans and hexapods is discussed. Two scenarios on the evolution of arthropod neurogenesis are presented. During the post-embryonic phase, the invaginating cell regions detach internally and form paired cell clusters at the apical ganglion sides. Each cluster remains connected to the ganglion soma cortex via fibrous cell streams. Increasing ganglion cell numbers and exclusive occurrence of mitoses within the cluster-stream-systems characterize the latter as post-embryonic neurogenic niches. Similarities to the neurogenic niche in the deutocerebrum of decapod crustaceans are discussed

    Bimanual Interaction with Clothes. Topology, Geometry, and Policy Representations in Robots

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    Twardon L. Bimanual Interaction with Clothes. Topology, Geometry, and Policy Representations in Robots. Bielefeld: Universität Bielefeld; 2019.If anthropomorphic robots are to assist people with activities of daily living, they must be able to handle all kinds of everyday objects, including highly deformable ones such as garments. The present thesis begins with a detailed problem analysis of robotic interaction with and perception of clothes. We show that handling items of clothing is very challenging due to their complex dynamics and the vast number of degrees of freedom. As a result of our analysis, we obtain a topological, geometric, and functional description of garments that supports the development of reduced object and task representations. One of the key findings is that the boundary components, which typically correspond with the openings, characterize garments well, both in terms of their topology and their inherent purpose, namely dressing. We present a polygon-based and an interactive method for identifying boundary components using RGB-D vision with application to grasping. Moreover, we propose Active Boundary Component Models (ABCMs), a constraint-based framework for tracking garment openings with point clouds. It is often difficult to maintain an accurate representation of the objects involved in contact-rich interaction tasks such as dressing assistance. Therefore, our policy optimization approach to putting a knit cap on a styrofoam head avoids modeling the details of the garment and its deformations. The experimental results suggest that a heuristic performance measure that takes into account the amount of contact established between the two objects is suitable for the task
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