http://hdl.handle.net/2117/3665 2013-05-20T22:25:20Z http://hdl.handle.net/2117/18453 Title: Explaining low farm-gate prices in the catalan wine sector: a Delphi study Authors: Costa Font, Montserrat; Serra Devesa, Teresa; Gil Roig, José María; Gras Moreu, Anna Maria 2013-03-21T12:59:31Z http://hdl.handle.net/2117/18009 Title: Modelización y simulación discreta con la plataforma NetLogo: ¿por qué caen las hojas en otoño? Authors: Ginovart Gisbert, Marta; Catalina, Merche; Blanco Abellán, Mónica Abstract: Los modelos basados en agentes (ABMs) describen a los individuos o partes que configuran un sistema como entidades autónomas y discretas, y focalizan toda su atención en caracterizar estas partes (agentes) mediante reglas de comportamiento, permitiendo la interacción entre ellas y con el entorno en el que se hallan. Se presenta el material docente diseñado para una actividad a realizar de forma autónoma en aula informática, centrada en el modelo “Autumn” que se encuentra en la plataforma NetLogo (de acceso libre desde la Web). Se analizan los resultados obtenidos con su implementación en los estudios de grado en Ingeniería de Biosistemas de la Universitat Politècnica de Catalunya. 2013-02-27T15:44:57Z http://hdl.handle.net/2117/16652 Title: Discovering the power of agent-based modelling to deal with complex systems in diverse contexts Authors: Ginovart Gisbert, Marta; Portell Canal, Xavier; Blanco Abellán, Mónica Abstract: Modelling is a necessary tool to represent, analyse and discuss aspects or ideas related to complex systems. With this in mind, teaching science based on the elaboration of models is widely accepted in the academic community. A relatively new methodology of modelling exists with a different philosophy and perspective from the classic and continuous models used up usually, the so-called agent-based models (ABMs). The general aim of the work is to make this kind of discrete modelling well-known, so that ABMs may be incorporated progressively into the academic curricula, complementing other existing modelling strategies. 2012-10-05T09:35:29Z http://hdl.handle.net/2117/14135 Title: Upgrading the uptake and metabolism sub-models of the Individual-based Model INDISIM-YEAST to tackle the behaviour of Saccharomyces cerevisiae in different culture conditions Authors: Portell Canal, Xavier; Gras Moreu, Anna Maria; Carbó Moliner, Rosa; Ginovart Gisbert, Marta 2011-12-01T12:27:02Z http://hdl.handle.net/2117/13753 Title: Optimization methods for individual-based model parameter estimation in predictive microbiology Authors: Prats Soler, Clara; Bernaerts, K.; Standaert, A.; Ferrer Savall, Jordi; López Codina, Daniel; Van Impe, J. Abstract: In the framework of microbiology, Individual-based Models are discrete models in which the main entities are microbes. Their use in simulations as ‘virtual experiments’ to predict the evolution of populations under specific conditions requires accurate setting of the parameters involved. We adapted and tested two optimization methods for Individual-based Model parameter estimation: the Nelder-Mead Threshold Accepting (NMTA) and the NEWUOA. These methods presented no convergence problems, and the best results in terms of time expenditure were derived with the latter. 2011-11-07T10:23:12Z http://hdl.handle.net/2117/13546 Title: Microbial individual-based models and sensitivity analyses: local and global methods Authors: Ginovart Gisbert, Marta; Prats Soler, Clara; Portell Canal, Xavier Abstract: A microbial Individual-based Model (IbM) to deal with yeast populations growing in liquid batch cultures has been designed and implemented in a simulator called INDISIM-YEAST. Interesting qualitative results have already been achieved with its use in the study of fermentation profiles, small inocula dynamics and lag phase, among others. Nevertheless, in order to improve its predictive capabilities and further development, a deeper comprehension of how the variation of the output of the model can be apportioned to different sources of variation must be investigated. One way to consider a sensitivity analysis for this IbM, providing an understanding of how the model response variables react to changes in the inputs, is the statistical study of well-designed computer experiments. The aim of this contribution is to show how the insights into nine individual cell parameters of INDISIMYEAST, mainly related to uptake and reproduction sub-models, can be obtained by combining local and global sensitivity analyses using simple and classic methods. From data obtained with an extensive set of computer experiments, a study of the variability observed in the evolution of two outputs of this model, ethanol production and mean biomass of the population, was performed. In addition, mono-factorial (one-at-a-time) analyses and ANOVA-based global analyses were also carried out on these two outputs. The model is clearly less sensitive to some parameters than others, depending on the output controlled. Moreover, this study allows identification of the parameters which have the greatest impact on the corresponding outputs and their significant first-order interactions. This work must be understood as an exercise to set up the procedure to be used in a sensitivity analysis study involving microbial IbMs. The knowledge gained will facilitate future parameterization and calibration of different parameters and outputs depending on the purpose of any study. 2011-10-17T14:41:30Z http://hdl.handle.net/2117/13510 Title: Sensitivity analysis and individual-based models in the study of yeast populations Authors: Ginovart Gisbert, Marta; Prats Soler, Clara; Portell Canal, Xavier Abstract: Individual-based models (IBMs), the biological agent-based models, are currently being applied to the study of microbial systems. A microbial IBM of yeast populations growing in liquid bath cultures has already been designed and implemented in the simulator called INDISIM-YEAST. In order to improve its predictive capabilities and further its development, a deeper understanding of how the variation of the output of the model can be apportioned, qualitatively or quantitatively, to different sources of variation must be investigated. The aim of this study is to show how insights into the individual cell parameters of INDISIM-YEAST can be obtained combining local and global methods using classic and well-proven methods, and to illustrate how these simple methods provide useful, reliable results with this IBM. This work deals mainly with the use of screening methods, as the main task to perform here is that of identifying the most influential factors for this microbial IBM. This screening exercise has allowed the establishment of significant input factors to this IBM on yeast population growth, and the highlighting of those that require greater attention in the parameterization and calibration processes. 2011-10-14T12:53:24Z http://hdl.handle.net/2117/12038 Title: INDISIM-SOM, an individual-based simulator on a website for experimenting and investigating diverse dynamics of Carbon and Nitrogen in mineral soils Authors: Gras Moreu, Anna Maria; Cañadas Lorenzo, Juan Carlos; Ginovart Gisbert, Marta Abstract: INDISIM-SOM models the dynamics and evolution of C and N related to organic matter in soils by using individual-based simulations. It is an Individual-based Model that controls a group of microbial cells at each time step, using a set of time-dependent variables for each microorganism. The space is divided into square cells. In each spatial cell, the amounts of different types of organic compounds are controlled. These are identified as polymerized organic C and N, labile organic C and N, and mineral compounds such us NNH4, NNO3, CO2 and O2. The model takes into account the activity of two types of microorganisms: decomposers (heterotrophic) and nitrifiers. Metabolic pathways and sources of C and N that they can use are identified. Some state variables and parameters related to soil organic matter and microbial activity are studied. This study presents a website at which the simulator INDISIM-SOM is accessible, and explains how to carry out some virtual experiments, in order to further advance the skills associated with this individual simulation model. 2011-03-23T15:54:26Z http://hdl.handle.net/2117/11872 Title: Análisis de la eficiencia de cuestionarios Moodle como herramienta de evolución de asignaturas de matemáticas correspondientes a primeros cursos de titulaciones de ingeniería Authors: Blanco Abellán, Mónica; Ginovart Gisbert, Marta 2011-03-16T11:35:52Z http://hdl.handle.net/2117/10040 Title: Analysis of the population structure of Plasmodium falciparum-infected erythrocytes Authors: Ferrer Savall, Jordi; Prats Soler, Clara; López Codina, Daniel; Gargallo Viola, Domingo; Valls Ribas, Joaquim 2010-10-28T08:56:00Z http://hdl.handle.net/2117/9992 Title: Moodle quizzes for assessing statistical topics in engineering studies Authors: Blanco Abellán, Mónica; Ginovart Gisbert, Marta 2010-10-26T10:48:15Z http://hdl.handle.net/2117/9679 Title: Repitching of yeast in beer fermentations: individual-based model simulations Authors: Ginovart Gisbert, Marta; Portell Canal, Xavier; Silbert, Moises 2010-10-14T06:42:23Z http://hdl.handle.net/2117/9678 Title: Repitching of yeast in beer fermentations: individual-based Model simulations Authors: Ginovart Gisbert, Marta; Portell Canal, Xavier; Silbert, Moises 2010-10-14T06:34:53Z http://hdl.handle.net/2117/9314 Title: Repitching of yeast in beer fermentations: Individual-based Model simulations Authors: Ginovart Gisbert, Marta; Portell Canal, Xavier; Silbert, Moises 2010-10-05T08:39:27Z http://hdl.handle.net/2117/9309 Title: BAETULO XXI, o de com arribar a Mart des de la secundària Authors: Serrano Porta, Lydia; Ramírez Alcántara, Jorge; Portell Canal, Xavier; Pijuan, Caterina; Monfort Peligero, Lluís; Ayza, Assumpta; Berenguer Sau, Jordi; Carnerero López, Sheila; Crespo Artiaga, Daniel; López Codina, Daniel; López Rubio, Juan; Lorén Aguilar, Pablo; Melo Vera, Maria Jesús 2010-10-05T07:35:52Z