72 research outputs found

    Estimating adaptive setpoint temperatures using weather stations

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    Reducing both the energy consumption and CO 2 emissions of buildings is nowadays one of the main objectives of society. The use of heating and cooling equipment is among the main causes of energy consumption. Therefore, reducing their consumption guarantees such a goal. In this context, the use of adaptive setpoint temperatures allows such energy consumption to be significantly decreased. However, having reliable data from an external temperature probe is not always possible due to various factors. This research studies the estimation of such temperatures without using external temperature probes. For this purpose, a methodology which consists of collecting data from 10 weather stations of Galicia is carried out, and prediction models (multivariable linear regression (MLR) and multilayer perceptron (MLP)) are applied based on two approaches: (1) using both the setpoint temperature and the mean daily external temperature from the previous day; and (2) using the mean daily external temperature from the previous 7 days. Both prediction models provide adequate performances for approach 1, obtaining accurate results between 1 month (MLR) and 5 months (MLP). However, for approach 2, only the MLP obtained accurate results from the 6th month. This research ensures the continuity of using adaptive setpoint temperatures even in case of possible measurement errors or failures of the external temperature probes.Spanish Ministry of Science, Innovation and Universities 00064742/ITC-20133094Spanish Ministry of Economy, Industry and Competitiveness BIA 2017-85657-

    Genetic programming to improvement FIB model: bond and anchorage of reinforcing steel in structural concrete

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    [Abstract] Starting from the FIB database, this work is aimed to analyze the current equations which predict the main datum that can be provided by bond tests: the ultimate bar stress when the failure is reached. Furthermore, Genetic Programming (GP) techniques are also applied in order to enhance the expression of the FIB, which achieves the best adjustment so far, giving rise to the new Model Code 2010. The final result shown is a highly predictive equation. The results are compared with those included in the Model Code and it is showed the influence of the main variables on the phenomenon (concrete strength, yield strength of steel, concrete cover, transverse reinforcement and diameter of the bar).Ministerio de Ciencia e Innovación; BIA2010-21551Galicia. Consellería de Economía e Industria; 10MDS014CTGalicia. Consellería de Economía e Industria; 10TMT042EGalicia. Consellería de Economía e Industria; 10TMT118004PRGalicia. Consellería de Economía e Industria; 10TMT034

    Optimization of existing equations using a new genetic programming algorithm: application to the shear strength of reinforced concrete beams

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    [Abstract] A method based on Genetic Programming (GP) to improve previously known empirical equations is presented. From a set of experimental data, the GP may improve the adjustment of such formulas through the symbolic regression technique. Through a set of restrictions, and the indication of the terms of the expression to be improved, GP creates new individuals. The methodology allows us to study the need of including new variables in the expression. The proposed method is applied to the shear strength of concrete beams. The results show a marked improvement using this methodology in relation to the classic GP and international code procedures.Ministerio de Ciencia e Innovación; BIA2007-60197Ministerio de Ciencia e Innovación; BIA2010-21551Xunta de Galicia; 08TMT005CTXunta de Galicia; 10TMT034

    Estimating Adaptive Setpoint Temperatures Using Weather Stations

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    [Abstract] Reducing both the energy consumption and CO2 emissions of buildings is nowadays one of the main objectives of society. The use of heating and cooling equipment is among the main causes of energy consumption. Therefore, reducing their consumption guarantees such a goal. In this context, the use of adaptive setpoint temperatures allows such energy consumption to be significantly decreased. However, having reliable data from an external temperature probe is not always possible due to various factors. This research studies the estimation of such temperatures without using external temperature probes. For this purpose, a methodology which consists of collecting data from 10 weather stations of Galicia is carried out, and prediction models (multivariable linear regression (MLR) and multilayer perceptron (MLP)) are applied based on two approaches: (1) using both the setpoint temperature and the mean daily external temperature from the previous day; and (2) using the mean daily external temperature from the previous 7 days. Both prediction models provide adequate performances for approach 1, obtaining accurate results between 1 month (MLR) and 5 months (MLP). However, for approach 2, only the MLP obtained accurate results from the 6th month. This research ensures the continuity of using adaptive setpoint temperatures even in case of possible measurement errors or failures of the external temperature probe

    Anatomy of the “false thumb” of Tremarctos ornatus (Carnivora, Ursidae, Tremarctinae) : phylogenetic and functional implications

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    Se describe por primera vez el sesamoideo radial o “falso pulgar” del oso de anteojos (Tremarctos ornatus), mostrando la gran similitud morfológica con el del panda gigante (Ailuropoda melanoleuca) y las diferencias que presenta con el resto de los Ursidae. Esto apunta a la existencia de un origen común para esta estructura en ambas especies, pero considerando las filogenias aceptadas de Ursidae, la presencia de falso pulgar en T. ornatus y A. melanoleuca sería una simplesiomorfía respecto al resto de úrsidos, en los cuales el sesamoideo radial nunca aumentó de tamaño, careciendo de la especializada función que posee en Tremarctinae y Ailuropodinae.We describe for the first time the radial sesamoid or “false thumb” of the spectacled bear (Tremarctos ornatus), showing its great morphological similarities with that of the giant panda (Ailuropoda melanoleuca) and the differences with that of the rest of the Ursidae. This points to the existence of a common origin for this structure in both species, but considering the accepted phylogenies of ursids, the sharing of a “false thumb” in T. ornatus and A. melanoleuca would be a plesiomorphy for these groups, whereas in the rest of the ursids the radial sesamoid was probably reduced, lacking the specialised function that this bone has in Tremarctinae and [email protected] [email protected]

    Investigation of Different Compressed Sensing Approaches for Respiratory Gating in Small Animal CT

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    Proceedings of: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC). Anaheim, California, USA. October 29 - November 3, 2012Respiratory gating is necessary in cardio-thoracic small-animal imaging because of the physiological motions that are present during scanning. When applying a low-dose protocol, fewer than 180 noisy projections may be left for the reconstruction of each respiratory phase, leading to streaking artifacts. The Prior Image Constrained Compressed Sensing (PICCS) algorithm enables accurate reconstruction of highly undersampled data when a prior image is available. The gradient domain is the preferred choice for enforcing the sparsity of the variation of each phase with respect to the prior. We evaluate three CS algorithms based on the Split-Bregman approach, with different transformations of the prior penalty function: Gradient (TV-PICCS), L1-norm (L1-PICCS), and Wavelet Transform (WT-PICCS), on low-dose data acquired on a micro-CT scanner. High-dose projection data, acquired with a cone-beam micro-CT scanner, were arranged into four gates using a software-based retrospective gating and reconstructed with an FDK algorithm. To simulate the low-dose case, we took 120 projections from each gate and added Poisson noise. Prior image was obtained by the addition of all low-dose gates with Gaussian filtering. All CS methods performed very similarly in terms of noise and resolution, greatly improving FBP (79 % noise reduction) and eliminating streaks. Pixel and wavelet domains were found to be sparser than the commonly used gradient domain. In conclusion, compressed sensing using a Split-Bregman methodology is a feasible approach to reduce dose in CT respiratory gating. The selection of the sparsity transform for the prior term does not affect resolution and noise performance but it has an influence on the final image texture: Wavelet transform showed a more natural pattern than TV and L1-norm.This work was supported in part by projects TEC2008-06715 and TEC2007-64731 (Ministerio de Ciencia e innovacion), EU-FP7 FMTXCT-201792, ARTEMIS S2009/DPI-1802 (Comunidad de Madrid), and European Regional Development Funds (FEDER) and CDTI under the CENIT program (AMIT project, CEN- 20101014).Publicad

    Segmentación automática de estudios PET cardíacos con ¹³NH_3 basada en correlación iterativa

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    Actas de: XXVIII Congreso Anual de la Sociedad Española de Ingeniería Biomédica (CASEIB 2010). Madrid, 24-26 de noviembre de 2010.La obtención de la función de entrada en estudios dinámicos de corazón a partir de la imagen PET se realiza habitualmente mediante la selección previa de una región de interés (ROI) o utilizando procedimientos de análisis factorial para encontrar aquellas curvas actividad/tiempo que mejor se adaptan a la función de entrada. En este trabajo se presenta un método novedoso de segmentación automática y obtención de la función de entrada que utiliza mapas de correlación calculados sobre estudios dinámicos que emplean ¹³NH_3 como trazador. Partiendo de un modelo analítico inicial, se buscan las curvas temporales más parecidas en el estudio real empleando la correlación. Tomando como datos estas curvas se calculan nuevos modelos con los que realizar sucesivas iteraciones. El resultado final es tanto una segmentación automática como la curva de actividad/tiempo de cada región segmentada.Ministerio de Ciencia e Innovación, TEC2007-64731, TEC 2008-06715-C02-1, la RETIC-RECAVA del Ministerio de Sanidad y Consumo, y el programa ARTEMIS S2009/DPI-1802 de la Comunidad de Madrid.Publicad

    Tracing the origin of the panda's thumb

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    © 2015, Springer-Verlag Berlin Heidelberg. We investigate the relative development of the carnivoran radial sesamoids to untangle the evolution of this iconic structure. In the pandas (both giant and red), this `false thumb¿ is known to perform a grasping role during bamboo feeding in both the red and giant pandas. An original locomotor role has been inferred for ailurids, but this remains to be ascertained for ursids. A large sample of radial sesamoids of Indarctos arctoides from the Miocene of Batallones-3 (Spain) indicates that this early ailuropodine bear displayed a relatively hypertrophied radial sesamoid, with a configuration more similar to that of the red panda and other carnivorans than to that of giant pandas. This false thumb is the first evidence of this feature in the Ursidae, which can be linked to a more herbivorous diet. Moreover, in the two extant pandas, the false thumb should not be interpreted as an anatomical convergence, but as an exaptive convergence regarding its use during the bamboo feeding, which changes the evolutionary view of this singular structure.This study was supported by the Spanish Ministerio de Economía y Competitividad (CGL2011-25754, CGL2011-28681 and RYC–2009–04533 to D.M.A.). A.V. is a researcher in formation in the CSIC program JAE-PRE_CP2011 (CSIC program‘ Junta para la ampliación de estudios’), co-funded by the European Social Fund and has received funding from the European Union’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 226506 (SYNTHESYS; SE-TAF-3637),Peer Reviewe

    A Novel Prior- and Motion-Based Compressed Sensing Method for Small-Animal Respiratory Gated CT

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    Low-dose protocols for respiratory gating in cardiothoracic small-animal imaging lead to streak artifacts in the images reconstructed with a Feldkamp-Davis-Kress (FDK) method. We propose a novel prior-and motion-based reconstruction (PRIMOR) method, which improves prior-based reconstruction (PBR) by adding a penalty function that includes a model of motion. The prior image is generated as the average of all the respiratory gates, reconstructed with FDK. Motion between respiratory gates is estimated using a nonrigid registration method based on hierarchical B-splines. We compare PRIMOR with an equivalent PBR method without motion estimation using as reference the reconstruction of high dose data. From these data acquired with a micro-CT scanner, different scenarios were simulated by changing photon flux and number of projections. Methods were evaluated in terms of contrast-to-noise-ratio (CNR), mean square error (MSE), streak artefact indicator (SAI), solution error norm (SEN), and correction of respiratory motion. Also, to evaluate the effect of each method on lung studies quantification, we have computed the Jaccard similarity index of the mask obtained from segmenting each image as compared to those obtained from the high dose reconstruction. Both iterative methods greatly improved FDK reconstruction in all cases. PBR was prone to streak artifacts and presented blurring effects in bone and lung tissues when using both a low number of projections and low dose. Adopting PBR as a reference, PRIMOR increased CNR up to 33% and decreased MSE, SAI and SEN up to 20%, 4% and 13%, respectively. PRIMOR also presented better compensation for respiratory motion and higher Jaccard similarity index. In conclusion, the new method proposed for low-dose respiratory gating in small-animal scanners shows an improvement in image quality and allows a reduction of dose or a reduction of the number of projections between two and three times with respect to previous PBR approaches.This work was funded by the Spanish Ministerio de Economía y Competitividad (www.mineco.gob.es/) with projects IDI-20130301, TEC2013-47270-R, IPT-2012-0401-300000, RTC-2014-3028-1, and RD12/0042/0057. Also, the research leading to these results has received funding from the Innovative Medicines Initiative (www.imi.europa.eu) Joint Undertaking under grant agreement n°115337, resources of which are composed of financial contribution from the European Union's Seventh Framework Programme (FP7/2007-2013) and EFPIA companies' in kind contribution. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Publicad

    Iterative Automatic Segmentation in cardiac PET based on TAC correlation: preliminary results

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    Proceeding of: 2010 IEEE Nuclear Science Symposium, Medical Imaging Conference and 17th Room Temperature Semiconductor Detector Workshop (IEEE), Knoxville, Tennessee, USA, October 30 - November 6, 2010Conventional kinetic parameter estimation based on compartmental models requires an accurate estimation of arterial blood input function. To avoid invasive blood sampling, an image-derived input function can be obtained by manually defining a Region of Interest. Here we propose a new and simple, iterative method for automatic segmentation and input function calculation of PET cardiac studies using correlation as a distance metric between a priori information regarding the approximate shape of the final time-activity curve (TAC) and the actual TAC extracted from the image temporal series.This work was supported in part by the CENIT-AMIT Ingenio 2010, Ministerio de Ciencia e Innovación, TEC2007-64731, TEC 2008-06715-C02-1, RETIC-RECAVA, Ministerio de Sanidad y Consumo, and the ARTEMIS de la Comunidad de Madrid (S2009/DPI-1802) programsPublicad
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