8,260 research outputs found

    A Robust Localization System for Inspection Robots in Sewer Networks †

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    Sewers represent a very important infrastructure of cities whose state should be monitored periodically. However, the length of such infrastructure prevents sensor networks from being applicable. In this paper, we present a mobile platform (SIAR) designed to inspect the sewer network. It is capable of sensing gas concentrations and detecting failures in the network such as cracks and holes in the floor and walls or zones were the water is not flowing. These alarms should be precisely geo-localized to allow the operators performing the required correcting measures. To this end, this paper presents a robust localization system for global pose estimation on sewers. It makes use of prior information of the sewer network, including its topology, the different cross sections traversed and the position of some elements such as manholes. The system is based on a Monte Carlo Localization system that fuses wheel and RGB-D odometry for the prediction stage. The update step takes into account the sewer network topology for discarding wrong hypotheses. Additionally, the localization is further refined with novel updating steps proposed in this paper which are activated whenever a discrete element in the sewer network is detected or the relative orientation of the robot over the sewer gallery could be estimated. Each part of the system has been validated with real data obtained from the sewers of Barcelona. The whole system is able to obtain median localization errors in the order of one meter in all cases. Finally, the paper also includes comparisons with state-of-the-art Simultaneous Localization and Mapping (SLAM) systems that demonstrate the convenience of the approach.Unión Europea ECHORD ++ 601116Ministerio de Ciencia, Innovación y Universidades de España RTI2018-100847-B-C2

    Verification in Generalizations of the 2-Handed Assembly Model

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    Algorithmic Self Assembly is a well studied field in theoretical computer science motivated by the analogous real world phenomenon of DNA self assembly, as well as the emergence of nanoscale technology. Abstract mathematical models of self assembly such as the Two Handed Assembly model (2HAM) allow us to formally study the computational capabilities of self assembly. The 2HAM is one of the most thoroughly studied models of self assembly, and thus in this paper we study generalizations of this model. The Staged Tile Assembly model captures the behavior of being able to separate assembly processes and combine their outputs at a later time. The k-Handed Assembly Model relaxes the restriction of the 2HAM that only two assemblies can combine in one assembly step. The 2HAM with prebuilt assemblies considers the idea that you can start your assembly process with some prebuilt structures. These generalizations relax some rules of the 2HAM, in ways which reflect real world self assembly mechanics and capabilities. We investigate the complexity of verification problems in these new models, such as the problem of verifying whether a system produces a specified assembly (Producibility), and verifying whether a system uniquely assembles a specified assembly (Unique Assembly Verification). We show that these generalizations introduce a high amount of intractability to these verification problems

    The Law and Economics of Habitat Conservation: Lessons from an Analysis of Easement Acquisitions

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    There is a growing interest in incentive-based policies to motivate conservation by landowners. These policies include full- and partial-interest land purchases, tax-based incentives, and tradable or bankable development rights. Using legal and economic analysis, this paper explores potential pitfalls associated with the use of such policies. Incentive-based policies promise to improve the cost effectiveness of habitat preservation, but only if long-run implementation issues are meaningfully addressed. While the paper compares conservation policies, particular attention is devoted to the use of conservation easements and in particular a set of easement contracts and transactions in the state of Florida. The easement analysis highlights the importance of conservation policies' interactions with property markets, land management practices, and bureaucratic incentives. Specific challenges include difficulties associated with the long-term enforcement and monitoring of land use restrictions, the lack of market prices as indicators of value for appraisal, and the way in which incentives target specific properties for protection.

    Discrete Variable Representation Of The Angular Variables In Quantum Three-Body Scattering

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    There are many numerical methods to study the quantum mechanical three-body scattering system using the Schrodinger equation. Traditionally, a partial-wave decomposition of the total wave function is carried out first, allowing the scattering system to be solved one partial wave at a time. This is convenient when the interaction is central, causing the total angular momentum to be conserved during the collision process. This is not possible in the presence of a non-central interaction such as a laser field, where the total angular momentum is not conserved during the collision process. The Discrete Variable Representation is a new method for solving the quantum-mechanical three-body scattering problem to obtain the total cross section. The implementation of this new method for the two-body problem has been successfully applied to real systems. The extension to the three-body problem is the next logical step. For this thesis bipolar spherical harmonics are used in the implementation of the three-body Discrete Variable Representation. This Discrete Variable Representation is capable of working with any combination of interactions, including non-central interactions. The total cross section computation for a three-particle elastic-scattering numerical example is used to illustrate the potential of this Discrete Variable Representation method. The three-particle system consists of a positron scattering against a ground state hydrogen atom (an electron bound to a proton)

    Poder e formação exclusões em Ciências da Saúde. Sugestões de melhoria na assistência ao paciente de complementaridade

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    Introducción: La importancia de los procesos de salud-enfermedad-atención es un hecho universal ejecutado a través de diferentes modelos. Occidente propone el modelo Biomédico, cuyos logros se ven limitados por la exclusión que realiza a las variables socio-culturales del enfermar. Objetivo: Una reflexión sobre las posibilidades de mejora que permitan una asistencia cercana al holismo, determinante no sólo de una mayor profesionalidad sino también de la conformación de una auténtica identidad enfermera, constituye el objetivo esencial. Metodología: Para intentar dar una respuesta sólida nos aventuraremos a la lectura de dos autores clásicos de la talla de Foucault y Gramsci, largamente referenciados en el ámbito de la Antropología médica, permitiéndonos sugerir una línea en la búsqueda de motivos y soluciones sobre la problemática que nos envuelve. Desarrollo: Una vía razonable se vislumbra en el aporte que las formas de atención complementarias posibilitan. En este sentido, la Enfermería actual debe buscar una vuelta a su ethos del cuidado, alejándose así de los preceptos deterministas que la han condenado a la subalternidad. Conclusiones: Un cambio en los patrones formativos se constituye como eje básico que determine una mejora real en los procesos de atención y permitan el derecho básico de una atención de calidad.Introduction: The importance of the health-disease-care is a universal fact executed through different models. West proposes the Biomedical model, whose achievements are limited by the exclusion that makes the socio-cultural variables of the sick. Objective: A reflection on the possibilities for improvement to enable a close to holism decisive assistance, not only for greater professionalism but also the formation of a real nurse identity, is the main objective. Methodology: To try to give, long referenced in the field of medical anthropology we venture robust response to the reading of two classics from the likes of Foucault and Gramsci, allowing us to suggest a line in the search for reasons and solutions on the problems surrounds us. Development: A reasonable way is looming on the contribution that complementary forms of care possible. In this sense, the current nursing should seek a return to its ethos of care, thus moving away from deterministic rules that have condemned the subaltern. Conclusions: A change in training patterns are established as key feature to determine real improvement in processes of care and allow the basic right to quality care.Introdução: A importância da saúde-doença-cuidado da saúde é um fato universal executado através de diferentes modelos. Ocidente propõe o modelo biomédico, cujas conquistas são limitados pela exclusão que faz com que as variáveis sócio-culturais do doente. Objetivo: Uma reflexão sobre as possibilidades de melhoria para permitir um fim à assistência decisiva holismo, não só para um maior profissionalismo, mas também a formação de uma identidade enfermeira real, é o objetivo principal. Metodologia: Para tentar dar uma, muito referenciado no campo da antropologia médica nos aventuramos resposta robusta para a leitura de dois clássicos de nomes como Foucault e Gramsci, o que nos permite sugerir uma linha na busca de razões e soluções sobre os problemas nos rodeia. Desenvolvimento: Uma maneira razoável é iminente sobre a contribuição que as formas complementares de cuidado possível. Neste sentido, a enfermagem atual deve buscar um retorno ao seu ethos do cuidado, afastando-se assim das regras deterministas que condenaram o subalterno. Conclusões: A mudança nos padrões de formação são estabelecidos como característica fundamental para determinar real melhoria nos processos de atendimento e permitir que o direito básico de cuidados de qualidade

    Analysis of proton exchange membrane fuel cell (PEMFC) design parameters by simulation using OpenFCST

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    Improving proton exchange membrane fuel cells technology, together with hy- drogen production and storage, can make these devices an important element in the energy transition puzzle. A multi-dimensional, non-isothermal, two- phase ow numerical full MEA model is used to simulate a real experiment. Once the results are validated, the same experimental model is used as a base- line to study the e ect of parallel channel and current collector widths in the PEMFC behavior. Further, the performance response is also evaluated for di erent cathode catalyst layer compositions, varying the platinum and elec- trolyte loadings. A part from these concrete studies, the model response to an individual parameter variation is evaluated, under wet and dry conditions, for parameters such as oxygen dissolution rate and water sorption constants, thermal and electrical conductivities and contact angle in the di erent media inside the cathode. The results show that keeping the baseline cathode catalyst layer thickness, 3.75 m, modifying channel widths to 0.13 cm and discretely through-plane grading the Pt/C content, the maximum power is increased by 15% with the same platinum loading when reactants are supplied with 90% relative humidity. In the case of 75%RH, the improving is around the 20% by just changing to 0.13 cm the channel width respect to the baseline.Outgoin

    Torsión testicular y su efecto en la fertilidad masculina en pacientes del Hospital Escuela Antonio Lenin Fonseca. Enero 2013-Octubre 2014, Managua-Nicaragua

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    La torsión testicular, produce alteraciones en el testículo contralateral sano, por mecanismos inmunológicos que aun no han sido muy bien esclarecidos y para los pacientes es motivo de preocupación la posibilidad de presentar infertilidad como efecto de una torsión testicular. Este estudio tuvo como objetivo general Describir los efectos de la torsión testicular en la fertilidad masculina en pacientes del Hospital Escuela Antonio Lenin Fonseca. Enero 2013 – Octubre 2014, Mangua-Nicaragua. Este es un estudio de series de casos, analizó 10 expedientes de pacientes que sufrieron torsión testicular; de los cuales todos eran jóvenes menores de 22 años de edad. Entre los principales resultados se destaca que: la principal manifestación clínica es el dolor intenso de inicio brusco. Además, se encontró que a un 80% de los afectados se les realizó orquiectomía mas orquidopexia. En la mayoría, transcurrieron más de doce horas entre la aparición de la torsión testicular y la conducta terapéutica empleada. En síntesis, se puede decir que la torsión testicular afecta los resultados del Espermatograma a largo plazo en cuanto a la movilidad y la morfología del espermatozoide. Palabras Clave: Torsión Testicular, Infertilidad, Espermatograma, Nicaragu

    The Infrared Database of Extragalactic Observables from Spitzer I: the redshift catalog

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    This is the first of a series of papers on the Infrared Database of Extragalactic Observables from Spitzer (IDEOS). In this work we describe the identification of optical counterparts of the infrared sources detected in Spitzer Infrared Spectrograph (IRS) observations, and the acquisition and validation of redshifts. The IDEOS sample includes all the spectra from the Cornell Atlas of Spitzer/IRS Sources (CASSIS) of galaxies beyond the Local Group. Optical counterparts were identified from correlation of the extraction coordinates with the NASA Extragalactic Database (NED). To confirm the optical association and validate NED redshifts, we measure redshifts with unprecedented accuracy on the IRS spectra ({\sigma}(dz/(1+z))=0.0011) by using an improved version of the maximum combined pseudo-likelihood method (MCPL). We perform a multi-stage verification of redshifts that considers alternate NED redshifts, the MCPL redshift, and visual inspection of the IRS spectrum. The statistics is as follows: the IDEOS sample contains 3361 galaxies at redshift 0<z<6.42 (mean: 0.48, median: 0.14). We confirm the default NED redshift for 2429 sources and identify 124 with incorrect NED redshifts. We obtain IRS-based redshifts for 568 IDEOS sources without optical spectroscopic redshifts, including 228 with no previous redshift measurements. We provide the entire IDEOS redshift catalog in machine-readable formats. The catalog condenses our compilation and verification effort, and includes our final evaluation on the most likely redshift for each source, its origin, and reliability estimates.Comment: 11 pages, 6 figures, 1 table. Accepted for publication in MNRAS. Full redshift table in machine-readable format available at http://ideos.astro.cornell.edu/redshifts.htm

    Videoactivismo y nuevos movimientos urbanos en España

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    El presente artículo analiza desde la economía política las funciones de la comunicación y la cultura en los actuales procesos de redefinición territorial y marketing urbano. Frente a este fenómeno, el texto aborda críticamente las formas de videoactivismo surgidas desde los nuevos movimientos urbanos en España, atendiendo a las tensiones presentes en estos espacios de resistencia cultural donde, a pesar de todo, se siguen materializando el conflicto, la diferencia y las contradicciones implícitas en las formas subalternas de acción colectiva. Dicha exploración trata de comprender los patrones de interacción entre nuevas formas de ciudadanía y la apropiación del espacio público a través de ejercicios de autoorganización que reconecten con la complejidad de las formas urbanas de sociabilidad
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