Simulació de fluxos de carboni terrestres mitjançant teledetecció i modelització d'ecosistemes

The main goal of this thesis is the establishment of a framework to analyze the Spanish forest ecosystems in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. Gross fluxes are estimated by a production efficiency model relying on the Monteith’s approach. The emphasis is put in characterizing the water stress effects on the light use efficiency and, eventually, on the GPP. Six alternatives are evaluated. Among them, the ones using the ratio between the MODIS actual and potential evapotranspiration, and the soil moisture from SMOS demonstrate that it is possible to characterize the water stress on GPP using only remote sensing products. Daily images of GPP are calculated and used as a reference in the rest of the thesis. The reference GPP is then used to calibrate and validate a semi-empirical model for the estimation of annual GPP. This model is a simplification of the Monteith approach that relies on a linear relationship between GPP and a PAR-weighted vegetation index (VI). This semi-empirical model can be used to estimate the annual GPP from commonly available VI images and a representative PAR, which does not require actual meteorological data. Therefore, inputs and computing time are considerably reduced. NDVI and EVI are tested. EVI does not need a land cover map, reducing the number of inputs even more. NDVI allows the elaboration of climatic studies that require long time series. Ecosystem respirations are simulated through Biome-BGC. A methodology to calibrate the rooting depth parameter, critical to the simulation of the water balance, is developed. The optimal rooting depth is obtained by comparing the reference GPP with the one simulated by Biome-BGC. The methodology is first tested in 4 validation sites and then extended to the whole study area. As a result, daily GPP maps and an optimal rooting depth map are obtained. Reference GPP and optimized respirations are used to calculate net fluxes. However, both GPP and respiration must be previously corrected. The first one because it represents the contribution of all the vegetation present in the considered area, not only the one from the forests. The second one because Biome-BGC works on equilibrium conditions and does not represent the actual state of the ecosystem. To do so, the necessary information layer, a growing stock map, is produced by the combination of the Third Spanish National Forest Inventory data (more than 50000 plot along the 1997-2007 period) and Landsat-5 TM and Landsat-7 ETM+ imagery (more than 8000 scenes covering the whole study area during the inventory period). Finally, preliminary net fluxes resulting from the corrected GPP and respirations are presented and validated.The main goal of this thesis is the establishment of a framework to analyze the Spanish forest ecosystems in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. Gross fluxes are estimated by a production efficiency model relying on the Monteith’s approach. The emphasis is put in characterizing the water stress effects on the light use efficiency and, eventually, on the GPP. Six alternatives are evaluated. Among them, the ones using the ratio between the MODIS actual and potential evapotranspiration, and the soil moisture from SMOS demonstrate that it is possible to characterize the water stress on GPP using only remote sensing products. Daily images of GPP are calculated and used as a reference in the rest of the thesis. The reference GPP is then used to calibrate and validate a semi-empirical model for the estimation of annual GPP. This model is a simplification of the Monteith approach that relies on a linear relationship between GPP and a PAR-weighted vegetation index (VI). This semi-empirical model can be used to estimate the annual GPP from commonly available VI images and a representative PAR, which does not require actual meteorological data. Therefore, inputs and computing time are considerably reduced. NDVI and EVI are tested. EVI does not need a land cover map, reducing the number of inputs even more. NDVI allows the elaboration of climatic studies that require long time series. Ecosystem respirations are simulated through Biome-BGC. A methodology to calibrate the rooting depth parameter, critical to the simulation of the water balance, is developed. The optimal rooting depth is obtained by comparing the reference GPP with the one simulated by Biome-BGC. The methodology is first tested in 4 validation sites and then extended to the whole study area. As a result, daily GPP maps and an optimal rooting depth map are obtained. Reference GPP and optimized respirations are used to calculate net fluxes. However, both GPP and respiration must be previously corrected. The first one because it represents the contribution of all the vegetation present in the considered area, not only the one from the forests. The second one because Biome-BGC works on equilibrium conditions and does not represent the actual state of the ecosystem. To do so, the necessary information layer, a growing stock map, is produced by the combination of the Third Spanish National Forest Inventory data (more than 50000 plot along the 1997-2007 period) and Landsat-5 TM and Landsat-7 ETM+ imagery (more than 8000 scenes covering the whole study area during the inventory period). Finally, preliminary net fluxes resulting from the corrected GPP and respirations are presented and validated

Remote sensing and ecosystem modeling to simulate terrestrial carbon fluxes

[EN] The main goal of this thesis is the establishment of a framework to analyze the forest ecosystems in peninsular Spain in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. The assessment of gross and net carbon fluxes is performed at 1-km spatial scale and on a daily basis using two different ecosystem models, Monteith and BIOME-BGC, respectively. These models are driven by a combination of satellite and ground data, part of the latter being also employed as a complementary data source and in the validation process.[ES] El objetivo principal de esta tesis es el desarrollo de un metodología operativa para analizar las zonas forestales de la península a través de los flujos de carbono que intercambian con la atmósfera. En concreto se ha evaluado la producción primaria bruta y la producción neta, ambas escala diaria y a 1 km de resolución espacial, con la aproximación de Monteith y el modelo BIOME-BGC, utilizando datos de satélite y diversos tipos de medidas en superficie. Estas últimas se emplean también en el proceso de validación.This thesis was developed in the framework of the project RESET CLIMATE CGL2012-35831 (Remote sensing of terrestrial essential climate variables: Water stress effect on carbon flux assessment) and ESCENARIOS CGL2016-75239-R (Monitoring carbon fluxes in forest ecosystems and simulation for climate change scenarios), both from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO), and co-financed by FEDER funds. The author was granted with the support of the Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016 (pre-doctoral scholarship BES-2013-064548). The research was carried out at the Environmental Remote Sensing Group of the University of Valencia, UV-ERS (www.uv.es/uvers).Sánchez-Ruiz, S. (2019). Simulación de flujos de carbono terrestres mediante teledetección y modelización de ecosistemas. Revista de Teledetección. (53):87-91. https://doi.org/10.4995/raet.2019.11220SWORD87915

The Drupal Framework: a Case Study to Evaluate Variability Testing Techniques

Variability testing techniques search for effective but manageable test suites that lead to the rapid detection of faults in systems with high variability. Evaluating the effectiveness of these techniques in real settings is a must but challenging due to the lack of variability-intensive systems with available code, automated tests and fault reports. in this paper, we propose using the Drupal framework as a case study to evaluate variability testing techniques. First, we represent the framework variability as a feature model. Then, we report on extensive data extracted from the Drupal git repository and the Drupal issue tracking system. Among other results, we identified 378 faults in single features and 11 faults triggered by the interaction between two of the features of Drupal v7.23, reported during a one-year period. These data may give a new insight into the distribution of faults in variability-intensive systems and the fault propensity of features. To show the feasibility of our work, we used the case study to evaluate the effectiveness of a historybased test case prioritization criterion. Results suggest that this technique could contribute to accelerate the detection of faults of test suites based on combinatorial testing.CICYT TIN2009-07366CICYT TIN2012-32273Junta de Andalucía TIC-5906Junta de Andalucía TIC-186

A Comparison of Test Case Prioritization Criteria for Software Product Lines

Software Product Line (SPL) testing is challenging due to the potentially huge number of derivable products. To alleviate this problem, numerous contributions have been proposed to reduce the number of products to be tested while still having a good coverage. However, not much attention has been paid to the order in which the products are tested. Test case prioritization techniques reorder test cases to meet a certain performance goal. For instance, testers may wish to order their test cases in order to detect faults as soon as possible, which would translate in faster feedback and earlier fault correction. in this paper, we explore the applicability of test case prioritization techniques to SPL testing. We propose five different prioritization criteria based on common metrics of feature models and we compare their effectiveness in increasing the rate of early fault detection, i.e. a measure of how quickly faults are detected. The results show that different orderings of the same SPL suite may lead to significant differences in the rate of early fault detection. They also show that our approach may contribute to accelerate the detection of faults of SPL test suites based on combinatorial testingMinisterio de Ciencia e Innovación TIN2009-07366 (SETI)Ministerio de Economía y Competitividad TIN2012-32273Junta de Andalucía P10-TIC-590

"¿Es posible una información crítica en TV?"

Se analiza el fenómeno del programa de televisión El intermedio, de La Sexta. Los inicios del proyecto, la repercusión, principales hitos alcanzados, recomendaciones a los estudiantes sobre cómo abordar las distintas facetas de las que se ocupa un programa de televisión de este corte (guion, reporterismo, etc.).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Coherent structures and bubble-particle velocity in 2-D fluidized beds

This work presents an experimental study to characterize ascending bubbles and granular velocity in the dense phase of a 2-D fluidized bed. Three different non-intrusive techniques based on images obtained with a high speed camera are developed, and applied to the images. First the bubble paths are characterized with time-average concentration maps and the bubble velocities are obtained, using a tracking algorithm over the mass centers of the bubbles. Finally, a PIV (particle image velocimetry) method is used to characterize the particle velocity vectors. This procedure is repeated for different bed aspect ratios, and different superficial gas velocities. This study analyzes the superficial gas velocity influence on the bed behavior, and how the bubble path configuration depends on the bed aspect ratio. The PIV measurements give us information on the location of the recirculation regions and the influence of the superficial gas velocity.Publicad

Automated Variability Analysis and Testing of an E-Commerce Site. An Experience Report

In this paper, we report on our experience on the development of La Hilandera, an e-commerce site selling haberdashery products and craft supplies in Europe. The store has a huge input space where customers can place almost three millions of different orders which made testing an ex-tremely di cult task. To address the challenge, we explored the applicability of some of the practices for variability management in software product lines. First, we used a feature model to represent the store input space which provided us with a variability view easy to understand, share and discuss with all the stakeholders. Second, we used techniques for the automated analysis of feature models for the detection and repair of inconsistent and missing con guration settings. Finally, we used test selection and prioritization techniques for the generation of a manageable and effective set of test cases. Our ndings, summarized in a set of lessons learnt, suggest that variability techniques could successfully address many of the challenges found when developing e-commerce sites.CICYT TIN2012-32273Junta de Andalucía TIC-5906Junta de Andalucía P12-TIC- 186

How children and adults keep track of real information when thinking counterfactually

This research was funded by grants from the Spanish Government, Ministry of Economy and Competitiveness (PSI2015-63505-P; PGC2018095868-B-I00) to SM and the Education, Culture and Sport Ministry (FPU15/05899) to JG. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.We are very grateful to the schools for their assistance with data collection and to the directors, teachers and children for their cooperation. Finally, we wish to thank Ruth Byrne and Cristina Vargas for their helpful comments.Thinking about counterfactual conditionals such as “if she had not painted the sheet of paper, it would have been blank” requires us to consider what is conjectured (She did not paint and the sheet was blank) and what actually happened (She painted and the sheet was not blank). In two experiments with adults (Study 1) and schoolchildren from 7 to 13 years (Study 2), we tested three potential sources of difficulty with counterfactuals: inferring, distinguishing what is real vs conjectured (epistemic status) and comprehending linguistic conditional expressions (“if” vs “even if”). The results showed that neither adults nor schoolchildren had difficulty in the comprehension of counterfactual expressions such as “even if” with respect to “if then”. The ability to infer with both of these develops during school years, with adults showing great ability. However, the third source factor is critical: we found that the key to young children’s difficulty with counterfactual thinking was their inability to differentiate real and conjectured information, while adults showed little difficulty with this.Spanish Government, Ministry of Economy and Competitiveness PSI2015-63505-P PGC2018095868-B-I00Education, Culture and Sport Ministry FPU15/0589

A Survey on Metamorphic Testing

A test oracle determines whether a test execution reveals a fault, often by comparing the observed program output to the expected output. This is not always practical, for example when a program’s input-output relation is complex and difficult to capture formally. Metamorphic testing provides an alternative, where correctness is not determined by checking an individual concrete output, but by applying a transformation to a test input and observing how the program output “morphs” into a different one as a result. Since the introduction of such metamorphic relations in 1998, many contributions on metamorphic testing have been made, and the technique has seen successful applications in a variety of domains, ranging from web services to computer graphics. This article provides a comprehensive survey on metamorphic testing: It summarises the research results and application areas, and analyses common practice in empirical studies of metamorphic testing as well as the main open challenges.European Commission (FEDER)Spanish Govermen