Papers by Carlos Fernando Guerrero Martínez
Este artículo muestra algunos avances logrados en una investigación que se viene desarrollando en... more Este artículo muestra algunos avances logrados en una investigación que se viene desarrollando en torno a conocimiento profesional del profesor de matemática del nivel superior asociado al uso de Ambientes Virtuales de Aprendizaje (AVA) cuando enseñan matemáticas. La utilidad de los AVA es sustentada desde los constructos formulados en la teoría conectivista, que pretende explicar la relación del aprendizaje con los recursos o dispositivos tecnológicos con conectividad. La metodología empleada se corresponde con el enfoque cualitativo de corte etnográfico. El objeto de estudio se abordó con cuatro docentes activos de matemáticas adscritos a la facultad de ingeniería que tiene la Fundación Universitaria del Área Andina. Para recoger la información se aplicaron cuestionarios, entrevistas semiestructuradas y observación de las prácticas docentes. La información se viene analizando mediante el método de codificación teórica. Se logra una categoría central denominada conocimiento didácti...
Water
Rainfall-runoff transformation on urban catchments involves physical processes governing runoff p... more Rainfall-runoff transformation on urban catchments involves physical processes governing runoff production in urban areas (e.g., interception, evaporation, depression, infiltration). Some previous 1D/2D coupled models do not include these processes. Adequate representation of rainfall–runoff–infiltration within a dual drainage model is still needed for practical applications. In this paper we propose a new modelling setup which includes the rainfall–runoff–infiltration process on overland flow and its interaction with a sewer network. We first investigated the performance of an outflow hydrograph generator in a 2D model domain. The effect of infiltration losses on the overland flow was evaluated through an infiltration algorithm added in a so-called Surf-2D model. Then, the surface flow from a surcharge sewer was also investigated by coupling the Surf-2D model with the SWMM 5.1 (Storm Water Management Model). An evaluation of two approaches for representing urban floods was carried ...
Hydrology, 2021
This paper presents the performance quantification of different green-grey infrastructures, inclu... more This paper presents the performance quantification of different green-grey infrastructures, including rainfall-runoff and infiltration processes, on the overland flow and its connection with a sewer system. The present study suggests three main components to form the structure of the proposed model-based assessment. The first two components provide the optimal number of green infrastructure (GI) practices allocated in an urban catchment and optimal grey infrastructures, such as pipe and storage tank sizing. The third component evaluates selected combined green-grey infrastructures based on rainfall-runoff and infiltration computation in a 2D model domain. This framework was applied in an urban catchment in Dhaka City (Bangladesh) where different green-grey infrastructures were evaluated in relation to flood damage and investment costs. These practices implemented separately have an impact on the reduction of damage and investment costs. However, their combination has been shown to b...
Sociedad de Educación Matemática de la Región de Murcia, SEMRM, 2015
RESUMEN ¿Te gustaría tener un libro que atraiga a los alumnos? ¿Un libro que sea interactivo? ¿Un... more RESUMEN ¿Te gustaría tener un libro que atraiga a los alumnos? ¿Un libro que sea interactivo? ¿Un libro que abarque las inteligencias múltiples? ¿Un libro flexible? ¿Un libro con videos, juegos, imágenes interactivas,…? Si tu respuesta a todas estas preguntas es afirmativa, la comunicación que presentamos es una muestra de ésto. Mediante algunos libros ejemplos que hemos realizado para nuestras clases de 5.º de Primaria y de 3.º de Secundaria queremos mostrar la variedad de opciones, flexibilidad, utilidad y atractivo de estos iBook que los alumnos pueden visualizar en el iPad.
Mikarimin, 2019
La investigación científica hoy en día se ha convertido en actividad principal dentro de la unive... more La investigación científica hoy en día se ha convertido en actividad principal dentro de la universidad ecuatoriana, pero lamentablemente ha quedado circunscrita a elites de docentes investigadores. Es por ello que la Facultad de Ciencias Administrativa de la Universidad Técnica de Quevedo decide fomentar la cultura de investigación a nivel de los estudiantes, para ello asume la estrategia didáctica denominada "aula invertida" cuya esencia operativa radica en el concepto de que el alumno debe aprender por si solo y desarrollar la práctica del conocimiento adquirido en el aula. Este hecho permitirá que el alumno investiga previamente a la clase, autogenere su conocimiento y este se lo fortifica en el aula con la práctica. Para el éxito de esta estrategia se re quiere que el Docente desarrolle una planificación de la sesión de aprendizaje, defina sitios web, libros y revistas donde consultar la temática, además debe diseñar la práctica sobre la temática consultada. En esta m...
IFAC-PapersOnLine, 2020
Fast growing E. coli cells in glucose-aerobic conditions excrete fermentation byproducts such as ... more Fast growing E. coli cells in glucose-aerobic conditions excrete fermentation byproducts such as acetate. This phenomenon is known as overflow metabolism and can pose a major problem in industrial bio-processes. In this paper, we study optimal control strategies for feeding a fed-batch reactor subject to overflow metabolism. We consider that acetate has an inhibitor effect on the glucose uptake, and we also consider the cost associated to process duration. In our approach, using the Pontryagin Maximum Principle and numerical solutions we describe the optimal feeding policy that maximizes biomass productivity and minimizes the cost duration of the process. We show that a singular regime is possible, in which cells grow at a slow rate to prevent acetate formation. If the cost associated to the process is too high, only bang-bang solutions are allowed.
Journal of Mathematical Biology, 2021
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
38th IAHR World Congress - "Water: Connecting the World", 2019
Over the past decades, there have been an increasing need to manage urban flooding. It is normall... more Over the past decades, there have been an increasing need to manage urban flooding. It is normally generated by the expansion of impervious areas and increased localized heavy rains. In urban flood modelling, the effect of infiltration has been normally considered to be not significant, minimum in relation to the rainfall or in most cases simplified to a constant infiltration rate. This paper presents a new and simplified modelling concept to evaluate the effect of infiltration on urban flooding. The evaluation is achieved by coupling a Non-Inertia 2D flood inundation model with a sewer network model through dynamic link libraries. An algorithm to simulate infiltration using the Green-Ampt method is included in the 2D model. The infiltration behaviour is expressed as a function of soil water content and the infiltration rate decays with time. The coupled models were compared to the results of a coupled 1D/2D model built in MIKE URBAN. Infiltration simulations were compared to previous measured experimental data. The results obtained suggest that this approach could be effective to provide quantitative performance values to support decision making as an alternative tool for modelling and evaluating rehabilitation measures. It also shows the importance of incorporating surface water infiltration process into the urban flood models.
Journal of Differential Equations, 2020
The periodically forced light-limited Droop model represents microalgae growth under co-limitatio... more The periodically forced light-limited Droop model represents microalgae growth under co-limitation by light and a single substrate, accounting for periodic fluctuations of factors such as light and temperature. In this paper, we describe the global dynamics of this model, considering general monotone growth and uptake rate functions. Our main result gives necessary and sufficient conditions for the existence of a positive periodic solution (i.e. a periodic solution characterized by the presence of microalgae) which is globally attractive. In our approach, we reduce the model to a cooperative planar periodic system. Using results on periodic Kolmogorov equations and on monotone sub-homogeneous dynamical systems, we describe the global dynamics of the reduced system. Then, using the theory of asymptotically periodic semiflows, we extend the results on the reduced system to the original model. To illustrate the applicability of the main result, we include an example considering a standard microalgae population model.
IFAC-PapersOnLine, 2018
Light supply is one of the most important parameters to be considered for enhancing microalgae gr... more Light supply is one of the most important parameters to be considered for enhancing microalgae growth in photobioreactors (PBR) with artificial light. However, most of the mathematical works do not consider incident light as a parameter to be optimized. In this work based on a simple model of light-limited growth, we determine optimal values for the dilution rate and the incident light intensity in order to maximize the steady-state microalgal surface productivity in a continuous culture. We also show that in optimal conditions there is a minimal initial microalgal concentration (and we give a simple expression to determine it) to guarantee the persistence of the population. Finally, in the context of enhancing microalgae productivity by reducing light absorption by microalgae, we conclude our work by studying the influence of the chlorophyll-carbon quota on the maximal productivity.
Water Resources Management, 2018
The present paper describes a framework for the evaluation of a drainage system's capacity in ord... more The present paper describes a framework for the evaluation of a drainage system's capacity in order to get a better understanding of the interactions between three rehabilitation measures: the Upgrading of Pipes (UP), Distributed Storage (DS) and the combination of both (UP+DS). It is posed as a multi-objective optimisation problem with the aim of minimising rehabilitation costs and flood damage. The approach of Expected Annual Damage Cost (EADC) was also introduced as the probabilistic cost caused by floods for a number of probable flood events (i.e. the accumulation of damage during a timeframe). The study combines computational tools such as a 1D/2D flood inundation model and an optimisation engine in the loop to compute potential damages for different rainfall events and to optimise combinations of rehabilitation measures. The advantages of this approach are demonstrated on a real-life case study in Dhaka City, Bangladesh. The optimal solutions confirm the usefulness and effectiveness of the proposed approach where both rehabilitation and damage costs are reduced by the optimal implementation of the UP and DS measures. In addition, the results of the proposed EADC approach indicate a damage cost reduction of at least 56% by implementing UP and of 27% by implementing DS, and both measures have lower rehabilitation costs. The proposed approach can be found appealing to water/wastewater utilities who are often challenged to achieve optimal design and rehabilitation of urban drainage systems.
Water, 2018
Green infrastructure (GI) has been regarded as an effective intervention for urban runoff reducti... more Green infrastructure (GI) has been regarded as an effective intervention for urban runoff reduction. Despite the growing interest in GI, the technical knowledge that is needed to demonstrate their advantages, cost, and performance in reducing runoff and pollutants is still under research. The present paper describes a framework that aims to obtain the optimal configuration of GI (i.e., the optimal number of units distributed within the catchment) for urban runoff reduction. The research includes an assessment of the performance of GI measures dealing with pollution load, peak runoff, and flood volume reduction. The methodological framework developed includes: (1) data input, (2) GI selection and placement, (3) hydraulic and water quality modelling, and (4) assessing optimal GI measures. The framework was applied in a highly urbanized catchment in Cali, Colombia. The results suggest that if the type of GI measure and its number of units are taken into account within the optimisation ...
Applied Sciences, 2017
The study of nanoparticles as additives for metalworking fluids (MWFs) with applications in the m... more The study of nanoparticles as additives for metalworking fluids (MWFs) with applications in the metal removal processes, or machining, has received increasing attention due to the possible enhancements on tribological properties. In this study, low-cost and environmentally friendly nanoparticle additives of halloysite clay nanotubes (HNTs) were dispersed in metalworking fluids utilized for milling processes. Concentrations of 0.01, 0.05, 0.10 wt. % were incorporated into a mineral oil (MO) and a semi-synthetic fluid (SF) by ultrasonication. The anti-wear properties of metalworking nanofluids were characterized with a T-05 block-on-ring tribotester at a contact pressure of 0.5 GPa. Surface roughness of worn block materials was obtained with an optical 3D surface measurement system. Results showed that at a concentration of 0.10 wt. % HNTs block mass loss was lowered by 24% for the MO + HNTs nanofluids. For the SF + HNTs, a reduction of 63% and 32% in wear mass loss and coefficient of friction (COF), respectively, were found at the same concentration. The tribological enhancing mechanism for the applied contact pressure was proposed to be due to a reduction of the area of contact and nanoparticle sliding between surfaces with no HNT deposition, evidenced by energy dispersive spectrometry (EDS). Furthermore, surface roughness studies of worn blocks showed smoother surfaces with lower groove density with the addition of nanoparticle additives. The results of this study demonstrate that HNTs can improve the lubricity of metalworking cutting fluids used for machining processes, enhancing tool life and providing better surface finish of products.
Entropy, 2018
The ease of interpretation of a classification model is essential for the task of validating it. ... more The ease of interpretation of a classification model is essential for the task of validating it. Sometimes it is required to clearly explain the classification process of a model’s predictions. Models which are inherently easier to interpret can be effortlessly related to the context of the problem, and their predictions can be, if necessary, ethically and legally evaluated. In this paper, we propose a novel method to generate rule-based classifiers from categorical data that can be readily interpreted. Classifiers are generated using a multi-objective optimization approach focusing on two main objectives: maximizing the performance of the learned classifier and minimizing its number of rules. The multi-objective evolutionary algorithms ENORA and NSGA-II have been adapted to optimize the performance of the classifier based on three different machine learning metrics: accuracy, area under the ROC curve, and root mean square error. We have extensively compared the generated classifier...
Journal of theoretical biology, Jan 16, 2018
Microalgae can be cultivated in closed or open photobioreactors (PBR). In these systems, light ra... more Microalgae can be cultivated in closed or open photobioreactors (PBR). In these systems, light rapidly decreases as it passes through the culture due to the turbidity of the medium. Thus, microalgae experiment different light intensities depending on their position in the medium. In this paper, we study theoretically how the growth rate of microalgae is affected by different factors; incident light intensity, form of the PBR, microalgae population density, turbidity of non-microalgae components, and light path-length of the reactor. We show that for different types of PBR the average growth rate is completely determined by the incident light intensity and the optical depth. In the case of vertical cylindrical PBRs illuminated from above (e.g. race-way or panel-type reactors), we described (and we prove under general assumptions) in details the dependence of the AGR on the aforementioned factors. Finally, we discuss some implications of our analysis; the occurrence of the Allee effec...
Frontiers in Neurology, 2016
Soft Computing, 2012
In this work, a data set describing phone interactions arising in a multichannel and multiskill c... more In this work, a data set describing phone interactions arising in a multichannel and multiskill contact centre is considered with the aim of classifying inbound sessions into those that will be eventually managed by an agent and those that, instead, will be abandoned before. More precisely, the goal of the work is to extract interpretable pieces of information that allow us to predict whether a user will or will not abandon a call, which may turn out to be very useful for the purpose of contact centre managing. To this end, the performance of two well-known, state-of-the-art evolutionary algorithms for feature selection (evolutionary nondominated radial slots based algorithm and nondominated sorted genetic algorithm) is compared for the task of feature selection, under the criteria of accuracy and cardinality of the selection, as well as for the task of fuzzy rule extraction, under the criteria of interpretability, accuracy, and hypervolume test. The best obtained fuzzy classifier, chosen after a decision making process, is validated and interpreted by domain experts.
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Papers by Carlos Fernando Guerrero Martínez