903 research outputs found

    Canvis tecnològics i estructures industrials: el calçat a la Vall del Vinalopó

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    A Study of the Combination of Variation Operators in the NSGA-II Algorithm

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    Multi-objective evolutionary algorithms rely on the use of variation operators as their basic mechanism to carry out the evolutionary process. These operators are usually fixed and applied in the same way during algorithm execution, e.g., the mutation probability in genetic algorithms. This paper analyses whether a more dynamic approach combining different operators with variable application rate along the search process allows to improve the static classical behavior. This way, we explore the combined use of three different operators (simulated binary crossover, differential evolution’s operator, and polynomial mutation) in the NSGA-II algorithm. We have considered two strategies for selecting the operators: random and adaptive. The resulting variants have been tested on a set of 19 complex problems, and our results indicate that both schemes significantly improve the performance of the original NSGA-II algorithm, achieving the random and adaptive variants the best overall results in the bi- and three-objective considered problems, respectively.UNIVERSIDAD DE MÁLAGA. CAMPUS DE EXCELENCIA INTERNACIONAL ANDALUCÍA TEC

    Improved Contrast Sensitivity DVS and its Application to Event-Driven Stereo Vision

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    This paper presents a new DVS sensor with one order of magnitude improved contrast sensitivity over previous reported DVSs. This sensor has been applied to a bio-inspired event-based binocular system that performs 3D event-driven reconstruction of a scene. Events from two DVS sensors are matched by using precise timing information of their ocurrence. To improve matching reliability, satisfaction of epipolar geometry constraint is required, and simultaneously available information on the orientation is used as an additional matching constraint.Ministerio de Economía y Competitividad PRI-PIMCHI-2011-0768Ministerio de Economía y Competitividad TEC2009-10639-C04-01Junta de Andalucía TIC-609

    Nonlinear time-domain macromodeling of OTA circuits

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    The authors present an accurate nonlinear macromodel of the operational transconductance amplifier (OTA) which is suitable for the transient simulation of OTA-based CMOS analog integrated circuits. As compared to device-level OTA models, the proposed macromodel is advantageous in terms of CPU time. Also, in circuits with many OTAs, it does not have the problems of convergence that the device-level MODEL has. All the macromodel parameters can be calculated from measurements made at the OTA terminals. Experimental results from a 3-μm CMOS OTA prototype as well as simulation results from device-level models are included and compared to simulation results from the macromodel

    Microplastics in the Antarctic marine system: An emerging area of research

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    It was thought that the Southern Ocean was relatively free of microplastic contamination; however, recent studies and citizen science projects in the Southern Ocean have reported microplastics in deep-sea sediments and surface waters. Here we reviewed available information on microplastics (including macroplastics as a source of microplastics) in the Southern Ocean. We estimated primary microplastic concentrations from personal care products and laundry, and identified potential sources and routes of transmission into the region. Estimates showed the levels of microplastic pollution released into the region from ships and scientific research stations were likely to be negligible at the scale of the Southern Ocean, but may be significant on a local scale. This was demonstrated by the detection of the first microplastics in shallow benthic sediments close to a number of research stations on King George Island. Furthermore, our predictions of primary microplastic concentrations from local sources were five orders of magnitude lower than levels reported in published sampling surveys (assuming an even dispersal at the ocean surface). Sea surface transfer from lower latitudes may contribute, at an as yet unknown level, to Southern Ocean plastic concentrations. Acknowledging the lack of data describing microplastic origins, concentrations, distribution and impacts in the Southern Ocean, we highlight the urgent need for research, and call for routine, standardised monitoring in the Antarctic marine system

    Presentation of the paper “Faat – Freelance as a Team”

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    [EN]This is the presentation of the paper entitled “Faat – Freelance as a Team” in the TEEM 2015 International Conference held in Porto (Portugal) in October 7-9, 2015. Agile methodologies are reliable engineering and management practices, capable of helping in the development of quality and successful software in business environments. However, most of these methodologies are centered on a development team and its internal communication. Moreover, for simplicity, a single product development is taken into account with its successive releases. There is another scenario: that of a single programmer working alone and often in much smaller projects and in several at the same time. Also in this scenario the client proximity is not as described by the agile environment ideal. In that case, the priorities and needs change, communication takes on another meaning and working mechanisms are not always comparable to that of a team. This paper introduces Faat (Freelance as a Team), a methodology specifically designed for those professionals. Integrating existing practices to the needs and possibilities of an individual programmer. However, it has been frequently considered the possible application of this methodology to small teams and/or other more general scenarios. This methodology has been tested in the web-based learning applications

    Performance Study of Software AER-Based Convolutions on a Parallel Supercomputer

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    This paper is based on the simulation of a convolution model for bioinspired neuromorphic systems using the Address-Event-Representation (AER) philosophy and implemented in the supercomputer CRS of the University of Cadiz (UCA). In this work we improve the runtime of the simulation, by dividing an image into smaller parts before AER convolution and running each operation in a node of the cluster. This research involves a test cases design in which the optimal parameters are set to run the AER convolution in parallel processors. These cases consist on running the convolution taking an image divided in different number of parts, applying to each part a Sobel filter for edge detection, and based on the AER-TOOL simulator. Execution times are compared for all cases and the optimal configuration of the system is discussed. In general, CRS obtain better performances when the image is divided than for the whole image.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

    Efeito da aplicação de altas pressões em chouriço de frango sem aditivos

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    A procura de produtos com carne de aves e sem aditivos é cada vez mais acentuada por parte dos consumidores. As indústrias alimentares tentam corresponder a estas exigências com o desenvolvimento de produtos isentos de aditivos mas garantindo a segurança alimentar. As altas pressões são uma alternativa interessante face aos métodos tradicionais de conservação de alimentos, uma vez que permitem aumentar a segurança microbiológica. O objetivo deste trabalho foi estudar o efeito das altas pressões em chouriço de frango sem adição de aditivos, produzido numa unidade industrial. Após o tratamento (600MPa por 8 min) as amostras foram armazenadas a 4 °C. O controlo microbiológico foi realizado no dia 0, 2 e 4 meses de conservação. Efetuaram-se contagens de bactérias lácticas mesófilas, bolores e leveduras, bactérias coliformes, Clostridium perfringens, estafilococos coagulase positivos, Escherichia coli ß-glucuronidase positiva, mesófilos, e psicrotróficos, e pesquisas de Listeria monocytogenes, Salmonella spp., segundo as normas internacionais. Os resultados apontam a ausência de Salmonella spp. e de Listeria monocytogenes em 25 g de produto. As contagens de Escherichia coli, bolores e leveduras, bactérias coliformes, Clostridium perfringens, e estafilococos coagulase positivos foram inferiores a 10 UFC g-1 em todas as amostras. As análises microbiológicas revelaram que as amostras com tratamento obtiveram contagens de bactérias lácticas mesófilas, mesófilos e psicrotróficos inferiores às contagens das amostras sem tratamento, com uma redução de 2 log. Esta redução poderá estar associada ao efeito das altas pressões ao nível da estrutura e integridade funcional da membrana citoplasmática dos microrganismos. Em suma, as altas pressões são uma técnica de grande interesse na indústria alimentar.info:eu-repo/semantics/publishedVersio

    Aplicação de altas pressões em chouriço de peru sem aditivos - segurança alimentar

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    As tecnologias emergentes de conservação dos alimentos têm como objetivo a segurança microbiológica, preservando a qualidade nutricional e sensorial ao longo do armazenamento. As altas pressões hidrostáticas são um método de conservação, alternativo aos processos térmicos existentes mais agressivos. O objetivo deste trabalho foi avaliar a aplicação de altas pressões em chouriço de peru produzido sem adição de aditivos numa unidade fabril e submetido a altas pressões (600MPa durante 8 min). As amostras foram armazenadas a 4 °C. Analisadas no dia da aplicação do tratamento e após 2 e 4 meses. Os parâmetros microbiológicos, designadamente contagens de bactérias lácticas mesófilas, bolores e leveduras, bactérias coliformes, Clostridium perfringens, estafilococos coagulase positivos, Escherichia coli ß-glucuronidase positiva, mesófilos, psicrotróficos, e pesquisa de Listeria monocytogenes, e de Salmonella spp., foram analisados recorrendo às metodologias definidas segundo as normas internacionais. Na pesquisa de patogénicos todas as amostras analisadas apresentaram um resultado de ausência em 25 g de produto. As contagens de Escherichia coli, bolores e leveduras, bactérias coliformes, Clostridium perfringens, e estafilococos coagulase positivos revelaram-se inferiores a 10 UFC g-1. As amostras submetidas a altas pressões hidrostáticas obtiveram contagens de bactérias lácticas mesófilas, mesófilos e psicrotróficos inferiores às contagens das amostras sem tratamento, desde o dia da aplicação do tratamento, com uma redução de 2 log. Perante os resultados obtidos, o fabrico de chouriço de peru sem aditivos e com aplicação de altas pressões hidrostáticas surge como um método de conservação do produto.N/

    Photoluminescent properties of electrochemically synthetized ZnO nanotubes

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    ZnO nanotubes were prepared by a sequential combination of electrochemical deposition, chemical attack and regeneration. ZnO nanocolumns were initially electrodeposited on conductive substrates and then converted into nanotubes by a process involving chemical etching and subsequent regrowth. The morphology of these ZnO nanocolumns and derived nanotubes was monitored by Scanning Electron Microscopy and their optical properties was studied by photoluminescence spectroscopy. Photoluminescence were measured as a function of temperature, from 6 to 300 K, for both nanocolumns and nanotubes. In order to study the behaviour of induced intrinsic defect all ZnO films were annealed in air at 400 °C and their photoluminescent properties were also registered before and after annealing. The behaviour of photoluminescence is explained taking into account the contribution of different point defects. A band energy diagram related to intrinsic defects was proposed to describe the behaviour of photoluminescence spectraThis work was supported by Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R) and Generalitat Valenciana (Prometeus 2014/044).Gracia Jimenez, JM.; Cembrero Cil, J.; Mollar García, MA.; Marí Soucase, B. (2016). Photoluminescent properties of electrochemically synthetized ZnO nanotubes. Materials Characterization. 119:152-158. https://doi.org/10.1016/j.matchar.2016.07.022S15215811
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