25 research outputs found

    High Resolution Vision-Based Servomechanism Using a Dynamic Target with Application to CNC Machines

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    This dissertation introduces a novel three dimensional vision-based servomechanism with application to real time position control for manufacturing equipment, such as Computer Numerical Control (CNC) machine tools. The proposed system directly observes the multi-dimensional position of a point on the moving tool relative to a fixed ground, thus bypassing the inaccurate kinematic model normally used to convert axis sensor-readings into an estimate of the tool position. A charge-coupled device (CCD camera) is used as the position transducer, which directly measures the current position error of the tool referenced to an absolute coordinate system. Due to the direct-sensing nature of the transducer no geometric error compensation is required. Two new signal processing algorithms, based on a recursive Newton-Raphson optimization routine, are developed to process the input data collected through digital imaging. The algorithms allow simultaneous high-precision position and orientation estimation from single readings. The desired displacement command of the tool in a planar environment is emulated, in one end of the kinematic chain, by an active element or active target pattern on a liquid-crystal display (LCD). On the other end of the kinematic chain the digital camera observes the active target and provides visual feedback information utilized for position control of the tool. Implementation is carried out on an XYθZ stage, which is position with high resolution. The introduction of the camera into the control loop yields a visual servo architecture; the dynamic problems and stability assessment of which are analyzed in depth for the case study of the single CAM- single image processing thread-configuration. Finally, two new command generation protocols are explained for full implementation of the proposed structure in real-time control applications. Command issuing resolutions do not depend upon the size of the smallest element of the grid/display being imaged, but can instead be determined in accordance with the sensor\u27s resolution

    Control de Garantías en los procesos penales del Departamento del Huila. Análisis de su nivel de eficiencia y garantía (2007)

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    Partiendo de la necesaria situación de establecer un nuevo sistema que respondiera de manera real y efectiva a la crisis de justicia y la mora que se venía presentando en las causas criminales, se hizo necesaria la adopción del nuevo Sistema de Procedimiento Penal de corte acusatorio, en el cual se destaca el protagonismo de la figura del Juez con funciones de Control de Garantías, que asume la tarea de garante de los derechos fundamentales del investigado así como de las víctimas.La difícil labor de lograr un equilibrio entre la realización de la justicia y la de asegurar la protección real de los derechos fundamentales de los sujetos procesales, es una responsabilidad que se evidenciará especialmente con el actuar de estos jueces. Ellos estarán sujetos entonces a la ponderación entre la persecución efectiva de las conductas delictivas, labor que representa el interés legítimo del Estado, y la salvaguarda de los derechos constitucionales que les asisten a quienes tienen la calidad de imputados, principalmente. Todo esto obliga a analizar cuál es la tendencia que en la práctica se mostrará con una mayor prevalencia respecto de estos dos puntos especialmente definitivos a la hora de evaluar la eficacia del Sistema Procesal Penal Acusatorio.

    Heritage and the Sea: Maritime History and Archaeology of the Global Iberian World (15th -18th centuries)

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    This two-volume set highlights the importance of Iberian shipbuilding in the centuries of the so-called first globalization (15th to 18th), in confluence with an unprecedented extension of ocean navigation and seafaring and a greater demand for natural resources (especially timber), mostly oak (Quercus spp.) and Pine (Pinus spp.). The chapters are framed in a multidisciplinary and interdisciplinary line of research that integrates history, Geographic Information Sciences, underwater archaeology, dendrochronology and wood provenance techniques. This line of research was developed during the ForSEAdiscovery project, which had a great impact in the academic and scientific world and brought together experts from Europe and America. The volumes deliver a state-of-the-art review of the latest lines of research related to Iberian maritime history and archaeology and their developing interdisciplinary interaction with dendroarchaeology. This synthesis combines an analysis of historical sources, the systematic study of wreck-remains and material culture related to Iberian seafaring from the 15th to the 18th centuries, and the application of earth sciences, including dendrochronology. The set can be used as a manual or work guide for experts and students, and will also be an interesting read for non-experts interested in the subject.Volume 1 focuses on the history and archaeology of seafaring and shipbuilding in the Iberian early modern world, complemented by case studies on timber trade and supply for shipbuilding, analysis of shipbuilding treatises, and the application of Geographic Information Systems and Databases (GIS) to the study of shipwrecks.Volume 2 focuses on approaches to the study of shipwrecks including a synthesis of dendro-archaeological results, current interdisciplinary case studies and the specialist study of artillery and anchors.Peer reviewe

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Pasados y presente. Estudios para el profesor Ricardo García Cárcel

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    Ricardo García Cárcel (Requena, 1948) estudió Historia en Valencia bajo el magisterio de Joan Reglà, con quien formó parte del primer profesorado de historia moderna en la Universidad Autónoma de Barcelona. En esta universidad, desde hace prácticamente cincuenta años, ha desarrollado una extraordinaria labor docente y de investigación marcada por un sagaz instinto histórico, que le ha convertido en pionero de casi todo lo que ha estudiado: las Germanías, la historia de la Cataluña moderna, la Inquisición, las culturas del Siglo de Oro, la Leyenda Negra, Felipe II, Felipe V, Austrias y Borbones, la guerra de la Independencia, la historia cultural, los mitos de la historia de España... Muy pocos tienen su capacidad para reflexionar, ordenar, analizar, conceptualizar y proponer una visión amplia y llena de matices sobre el pasado y las interpretaciones historiográficas. A su laboriosidad inimitable se añade una dedicación sin límites en el asesoramiento de alumnos e investigadores e impulsando revistas, dosieres, seminarios o publicaciones colectivas. Una mínima correspondencia a su generosidad lo constituye este volumen a manera de ineludible agradecimiento

    Artificial water bodies as amphibian breeding sites: the case of the common midwife toad (Alytes obstetricans) in central Spain

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    Natural breeding sites for amphibians are decreasing in quantity and quality in temperate regions, resulting in local extinctions and increasing population fragmentation. Artificial water bodies (e.g., water tanks or cattle troughs) can represent suitable reproductive habitats for some amphibians, but demographic data are required to assess this assumption. We evaluated the role of artificial water bodies in the persistence of a species of population concern, the common midwife toad, Alytes obstetricans (Laurenti, 1768), at local and regional scales. We surveyed 275 water bodies to characterize the distribution of the species and detected 63 breeding populations of A. obstetricans where we estimated larval abundance. In addition, we monitored two populations for three consecutive breeding seasons using capture-mark-recapture methods based on photo-identification, assessing abundance, breeding success and the use of space of adult individuals captured on multiple occasions. Our results show that artificial sites are preferentially used as breeding sites in the region compared to natural aquatic habitats, providing key habitat for the species and hosting much larger numbers and densities of larvae than natural sites. At local scale, populations of A. obstetricans in artificial sites were abundant and characterized by high male breeding success. However, adults are spatially aggregated around breeding sites, with small home ranges, implying high vulnerability to population fragmentation. Our results suggest artificial breeding sites can sustain viable populations of A. obstetricans, provided measures promoting connectivity among breeding nuclei are considered.Peer reviewe

    A report of complete albinism in an adult Pleurodeles waltl in the wild

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    El albinismo es una de las anomalías pigmentarias más documentadas en los anfibios, aunque en poblaciones naturales se da con poca frecuencia, posiblemente porque los animales con fenotipos albinos presentarían tasas de supervivencia menores que aquellos con fenotipo normal. En esta nota describimos una observación de una hembra adulta albina de gallipato (Pleurodeles waltl) en una charca temporal en la Comunidad de Madrid y aportamos documentación gráfica de este caso de albinismo completo.Peer reviewe

    The role of artificial breeding sites in amphibian conservation:A case study in rural areas in central spain

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    Amphibians in rural landscapes often utilize various types of artificial constructions originally designed for irrigation, livestock supply, or other purposes (e.g., water tanks or cattle troughs) as breeding sites. These sites potentially function as local refugia; however, their importance for amphibian communities has yet to be widely assessed. Here we evaluate the role of artificial constructions in the persistence of amphibian populations in rural areas of central Spain, focusing on two species of conservation concern: the Common Midwife Toad, Alytes obstetricans (Laurenti 1768), and the Parsley Frog, Pelodytes punctatus (Daudin 1802). We surveyed 130 water bodies at 113 localities in an area of 1,450 km during the breeding season of 2018 and documented the type of breeding site, species abundance, amphibian community structure, and any detectable threats. We found non-random patterns of breeding site selection and amphibian species co-occurrence in which A. obstetricans tended to inhabit artificial water tanks with simpler amphibian communities, whereas P. punctatus tended to co-occur in naturalized ponds in abandoned quarries with complex amphibian community structures. We discuss the relevance of artificial breeding sites for the resilience of amphibian populations and propose conservation measures to improve their efficiency in the face of detected threats, including trap effects, alien species, and chytridiomycosis
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