379 research outputs found
Chaos on Fuzzy Dynamical Systems
No full textGiven a continuous map f:X→X on a metric space, it induces the maps f¯:K(X)→K(X), on the hyperspace of nonempty compact subspaces of X, and f^:F(X)→F(X), on the space of normal fuzzy sets, consisting of the upper semicontinuous functions u:X→[0,1] with compact support. Each of these spaces can be endowed with a respective metric. In this work, we studied the relationships among the dynamical systems (X,f), (K(X),f¯), and (F(X),f^). In particular, we considered several dynamical properties related to chaos: Devaney chaos, A-transitivity, Li–Yorke chaos, and distributional chaos, extending some results in work by Jardón, Sánchez and Sanchis (Mathematics 2020, 8, 1862) and work by Bernardes, Peris and Rodenas (Integr. Equ. Oper. Theory 2017, 88, 451–463). Especial attention is given to the dynamics of (continuous and linear) operators on metrizable topological vector spaces (linear dynamics)
Satellite image processing for the coarse-scale investigation of sandy coastal areas
No full textIn recent years, satellite imagery has shown its potential to support the sustainable management of land, water, and natural resources. In particular, it can provide key information about the properties and behavior of sandy beaches and the surrounding vegetation, improving the ecomor-phological understanding and modeling of coastal dynamics. Although satellite image processing usually demands high memory and computational resources, free online platforms such as Google Earth Engine (GEE) have recently enabled their users to leverage cloud-based tools and handle big satellite data. In this technical note, we describe an algorithm to classify the coastal land cover and retrieve relevant information from Sentinel-2 and Landsat image collections at specific times or in a multitemporal way: the extent of the beach and vegetation strips, the statistics of the grass cover, and the position of the shoreline and the vegetation–sand interface. Furthermore, we validate the algorithm through both quantitative and qualitative methods, demonstrating the goodness of the derived classification (accuracy of approximately 90%) and showing some examples about the use of the algorithm’s output to study coastal physical and ecological dynamics. Finally, we discuss the algorithm’s limitations and potentialities in light of its scaling for global analyses.Coastal Engineerin
Collaboration Bologna-ISIB
No full textIn light of the recommendations of the 1st workshop, an ongoing collaboration has been established between the CHERNE partners ISB and University of Bologna
Collaboration Bologna-Juelich on simulation tools for the developmentof a novel neutron generator
No full textIn the wake of CHERNE, the two partner Universities, Bologna and Juelich, have developed a scientific project to be tackled jointly. Aim of this project is the development and thorough experimental validation of Montecarlo simulation codes capable of affording great predicting capability for the design of a novel, multipurpose, variable geometry neutron source. The project will also have strong educational fall-out, as many Master and Doctoral students will take part in it as Thesis/Dissertation project
Utilidad de las fórmulas CDK-EPI y MDRD-4 para estimar el índice de filtración glomerular en pacientes con patología glomerular
No full textMore than 40 formulas have been developed to estimate the glomerular filtration rate (GFR) involving creatinine concentration (Cr) as well as demographic and anthropometric variables. Modification of Diet in Renal Disease (MDRD-4) is the most recommended one. However, several studies state that Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation improves the results obtained with MDRD-4. Our aim was to compare the results of the estimated GFR (eGFR) obtained with both formulas in patients with glomerular pathology. We studied 32 individuals with glomerulopathies, age (mean±SD): 34±8 years old, 24 females (F) and 8 males (M). Cr was assessed by an automated method. Results were expressed as mean±SD. eGFR (ml/min) with CKD-EPI and MDRD-4 were 102±41 and 105±51 respectively; no significant differences were obtained between both formulas (p>0.05). Correlation coefficient between both equations was highly significant (r=0.93; p0.05). We conclude that both formulas could be used indistinctly as estimators of GFR in patients with glomerular pathology. For GFR values > normal values, eGFR with both equations would tend to a poorer correlation, then stratification and comparison of these values with those obtained from Cr clearance are suggested in order to determine which equation would be the best analytical predictor in patients with glomerulopathy and glomerular hyperfiltration.Fil: Pezzarini, Eleonora. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Rossi, María F. Universidad Nacional de Rosario. Facultad de Ciencias Médicas; ArgentinaFil: Rossi, María F. Provincia de Santa Fe. Hospital Provincial del Centenario. Servicio de Nefrología; ArgentinaFil: Balbi, Bárbara. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Monje, Adriana L. Universidad Nacional de Rosario. Facultad de Ciencias Médicas; ArgentinaFil: Monje, Adriana L. Provincia de Santa Fe. Hospital Provincial del Centenario. Servicio de Nefrología; ArgentinaFil: Ocampo Alzate, Carlos. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Basiglio, Cecilia Lorena. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Basiglio, Cecilia L. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE-CONICET); ArgentinaFil: Rodenas, M. Universidad Nacional de Rosario. Facultad de Ciencias Médicas; ArgentinaFil: Rodenas, M. Provincia de Santa Fe. Hospital Provincial del Centenario. Servicio de Nefrología; Provincia de Santa Fe. Hospital Provincial del Centenario. Servicio de Nefrología; ArgentinaFil: Daniele, Stella Maris. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Arriaga, Sandra Mónica María. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; ArgentinaFil: Pelusa, Héctor Fabián. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Área Bioquímica Clínica; Argentin
Uncertainty analysis in integrated catchment modelling
No full textThe adoption of increasingly restrictive water quality standards is directed to maintain natural ecosystems in a good status. Complying with such standards requires significant investments in water infrastructure and operations. Consequently, mathematical simulation is usually applied to assist in the decision-making process for such large-scale actuations. In particular, environmental models are proposed to represent the wastewater cycle in natural water bodies, such that the effect of different pollution mitigation alternatives can be estimated. Integrated catchment models (ICM) aim at simulating water quality dynamics by representing the link between urban drainage networks, wastewater treatment operations, rural hydrology and river physical-biochemical processes. However, these subsystems present dynamics acrossmultiple spatiotemporal scales and many relevant processes are still not fully understood. System observations are scarce and often insufficient to identify most model representations. As a result, ICM studies often produce significant output uncertainties
Observation of charge transfer cascade in α-Fe2O3/IrO2 photoanodes by in-operando X-rays absorption spectroscopy
No full textIn this work we show the direct observation, by means of spectro-photoelectrochemical experiments, of charge transfer between a semiconductor (-Fe2O3) and a metal oxide overlayer (hydrous IrOx) as a photoanode architecture in photoelectrochemical water splitting.1 The aim is to clarify the ambiguous role of oxygen evolving catalysts used as overlayers on top of photoanodes in photoelectrochemical water splitting cells. Previous literature suggested that the real benefit of covering hematite with overlayers like iridium or cobalt oxides is not due to an increase of reaction kinetics but the decrease of the electron density in the hematite2 or the storage of photogenerates holes.3 These effects are likely more important when hydrous overlayer, that can act as adapting catalysts,4 are considered. All these hypothesis can explain the observed improved hole lifetime and reduce recombination with electrons.
The present experimental approach is similar to the one that allowed our recent disclosure of the oxidation states assumed by hydrous IrOx as catalyst for water oxidation.5 In the present case, FEXRAV6 and XANES have been used to probe changes in the charge state of Ir while the hematite was illuminated with 410nm radiation. Thanks to this in-operando setup, we were able to observe an increase of the density of empty Ir 5d states during hematite illumination and in correspondence of water spitting in the photoelectrochemical cell. The main conclusion is that a charge (hole) transfer between hematite and iridium occurs only when the hematite is illuminated. Hydrous iridium oxide is therefore capable of withdrawing holes from the semiconductor thus increasing the probability of interface reaction rather than charge recombination.
1 Minguzzi A., Lugaresi O., Achilli E., D'Acapito F., Naldoni A., Malara F., Locatelli C., Vertova A., Rondinini S., Ghigna P., In preparation
2 Badia-Bou L., Mas-Marza E., Rodenas P., M. Barea E., Fabregat-Santiago F., Gimenez S., Peris E., Bisquert J., J. Phys. Chem. C, 2013, 117, 3826−3833
3 Lin F., Boettcher S.W. Nature Materials, 2014, 13, 81-86
4 Barroso M., Mesa C.A., Pendlebury S.R. , Cowana A.J., Hisatomi T., Sivula K., Grätzel M., Klug D.R., Durrant J.R. PNAS, 2012, 109, 15640–15645
5 Minguzzi A., Lugaresi O., Achilli E., Locatelli C., Vertova A., Ghigna P., Rondinini S., Chem. Sci., 2014, 5, 3591-3597
6 Minguzzi, A.; Lugaresi, O.; Locatelli, C.; Rondinini S.; d'Acapito, F.; Achilli, E.; Ghigna, P. Anal. Chem. 2013, 85, 7009-7013
Uncertainty analysis in a large-scale water quality integrated catchment modelling study
No full textReceiving water quality simulation in highly urbanised areas requires the integration of several processes occurring at different space-time scales. These integrated catchment models deliver results with a significant uncertainty level associated. Still, uncertainty analysis is seldom applied in practice and the relative contribution of the individual model elements is poorly understood. Often the available methods are applied to relatively small systems or individual sub-systems, due to limitations in organisational and computational resources. Consequently this work presents an uncertainty propagation and decomposition scheme of an integrated water quality modelling study for the evaluation of dissolved oxygen dynamics in a large-scale urbanised river catchment in the Netherlands. Forward propagation of the measured and elicited uncertainty input-parametric distributions was proposed and contrasted with monitoring data series. Prior ranges for river water quality-quantity parameters lead to high uncertainty in dissolved oxygen predictions, thus the need for formal calibration to adapt to the local dynamics is highlighted. After inferring the river process parameters with system measurements of flow and dissolved oxygen, combined sewer overflow pollution loads became the dominant uncertainty source along with rainfall variability. As a result, insights gained in this paper can help in planning and directing further monitoring and modelling efforts in the system. When comparing these modelling results to existing national guidelines it is shown that the commonly used concentration-duration-frequency tables should not be the only metric used to select mitigation alternatives and may need to be adapted in order to cope with uncertainties.Sanitary EngineeringIntegral Design & Managemen
Comparison of automatic classifiers'performances using word-based feature extraction techniques in an e-government setting
No full textProjecte realitzat mitjançant programa de mobilitat. KUNGLIGA TEKNISKA HÖGSKOLAN, STOCKHOLMNowadays email is commonly used by citizens to establish communication with their government. On the received emails, governments deal with some common queries and subjects which some handling officers have to manually answer. Automatic email classification of the incoming emails allows to increase the communication efficiency by decreasing the delay between the query and its response. This thesis takes part within the IMAIL project, which aims to provide an automatic answering solution to the Swedish Social Insurance Agency (SSIA) (¿Försäkringskassan¿ in Swedish). The goal of this thesis is to analyze and compare the classification performance of different sets of features extracted from SSIA emails on different automatic classifiers. The features extracted from the emails will depend on the previous preprocessing that is carried out as well. Compound splitting, lemmatization, stop words removal, Part-of-Speech tagging and Ngrams are the processes used in the data set. Moreover, classifications will be performed using Support Vector Machines, k- Nearest Neighbors and Naive Bayes. For the analysis and comparison of different results, precision, recall and F-measure are used. From the results obtained in this thesis, SVM provides the best classification with a F-measure value of 0.787. However, Naive Bayes provides a better classification for most of the email categories than SVM. Thus, it can not be concluded whether SVM classify better than Naive Bayes or not. Furthermore, a comparison to Dalianis et al. (2011) is made. The results obtained in this approach outperformed the results obtained before. SVM provided a F-measure value of 0.858 when using PoS-tagging on original emails. This result improves by almost 3% the 0.83 obtained in Dalianis et al. (2011). In this case, SVM was clearly better than Naive Bayes
Assessment of oral and written communication competences in the European Higher Education Area: a proposal of evaluation methodologies
No full text[EN] he international accreditation for the Master and Bachelor degrees offered at our university, together with the demands of the employers, have made it clear that the students’ curricula should specify not only what they have studied, but also what they are actually able to do. Although the competence based curricula approach has been used in the development of the new programmes for the Master and Bachelor degrees within the European Higher Education Area in recent years, the assessment of these competences is still a pending task. This work presents an ‘outcomes’ approach for the assessment of the oral and written communication skills within subjects related to mechanical and materials engineering. In particular, this paper proposes some rubrics developed in order to quantify the level of achievement. These rubrics are based on the evaluation of some learning outcomes that can be observed by using different strategies during the course. Conclusions about preliminary results and the difficulties found in order to create these tools are also described here.Sonseca, A.; Sahuquillo, O.; Martinez-Casas, J.; Carballeira, J.; Denia Guzmán, FD.; Rodenas, J. (2015). Assessment of oral and written communication competences in the European Higher Education Area: a proposal of evaluation methodologies. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 2-9. https://doi.org/10.4995/HEAD15.2015.485OCS2
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