DSpace Repository :: Browsing by Author "Bosch, Paul"

Browsing by Author "Bosch, Paul"

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A horizontal collaborative approach for planning the wine grape harvesting
(2022) Basso, Franco; Varas, Mauricio; Bosch, Paul; Contreras, Juan Pablo; Pezoa, Raúl
Horizontal collaboration is a strategy that has increasingly been used for improving supply chain operations. In this paper, we analyze the benefits of using a collaborative approach when optimally planning the wine grape harvesting process. Particularly, we assess how labor and machinery collaborative planning impacts harvesting costs. We model cooperation among wineries as a coalitional game with transferable costs for which the characteristic function vector is computed by solving a new formulation for planning the wine grape harvesting. In order to obtain stable coalitions, we devise an optimization problem that incorporates both rationality and efficiency conditions and uses the Gini index as a fairness criterion. Focusing on an illustrative case, we develop several computational experiments that show the positive effect of collaboration in the harvesting process. Moreover, our computational results reveal that the results depend strongly on the fairness criteria used. The Gini index, for example, favors the formation of smaller coalitions compared to other fairness criteria such as entropy.
A New Genetic Algorithm Encoding for Coalition Structure Generation Problems
(2020) Contreras, Juan Pablo; Bosch, Paul; Varas, Mauricio; Basso, Franco
Genetic algorithms have proved to be a useful improvement heuristic for tackling several combinatorial problems, including the coalition structure generation problem. In this case, the focus lies on selecting the best partition from a discrete set. A relevant issue when designing a Genetic algorithm for coalition structure generation problems is to choose a proper genetic encoding that enables an efficient computational implementation. In this paper, we present a novel hybrid encoding, and we compare its performance against several genetic encoding proposed in the literature. We show that even in difficult instances of the coalition structure generation problem, the proposed approach is a competitive alternative to obtaining good quality solutions in reasonable computing times. Furthermore, we also show that the encoding relevance increases as the number of players increases.
Analysis of dengue fever outbreak by generalized fractional derivative
(2020) Bosch, Paul; Gómez-Aguilar, J. F.; Rodríguez, José Manuel; Sigarreta, José María
In this paper, we use the generalized fractional derivative in order to study the fractional differential equation associated with a fractional Gaussian model. Moreover, we propose new properties of generalized differential and integral operators. As a practical application, we estimate the order of the derivative of the fractional Gaussian models by solving an inverse problem involving real data on the dengue fever outbreak.
Comment on “An algorithm for moment-matching scenario generation with application to financial portfolio optimization"
(2018) Contreras, Juan Pablo; Bosch, Paul; Herrera, Mauricio
A paper by Ponomareva, Roman, and Date proposed a new algorithm to generate scenarios and their probability weights matching exactly the given mean, the covariance matrix, the average of the marginal skewness, and the average of the marginal kurtosis of each individual component of a random vector. In this short communication, this algorithm is questioned by demonstrating that it could lead to spurious scenarios with negative probabilities. A necessary and sufficient condition for the appropriate choice of algorithm parameters is derived to correct this issue.
Dirichlet Type Problem for 2D Quaternionic Time-Harmonic Maxwell System in Fractal Domains
(2020) Peña Pérez, Yudier; Abreu Blaya, Ricardo; Bosch, Paul; Bory Reyes, Juan
We investigate an electromagnetic Dirichlet type problem for the 2D quaternionic time-harmonic Maxwell system over a great generality of fractal closed type curves, which bound Jordan domains in . The study deals with a novel approach of -summability condition for the curves, which would be extremely irregular and deserve to be considered fractals. Our technique of proofs is based on the intimate relations between solutions of time-harmonic Maxwell system and those of the Dirac equation through some nonlinear equations, when both cases are reformulated in quaternionic forms.
Diseño e Implementación de micro biodigestor sensorizado para la producción de bio-insumos
(Universidad del Desarrollo. Facultad de Ingeniería, 2024) Guzmán Cood, Sebastián; Bosch, Paul; Camilo Rodriguez
De acuerdo con la Estrategia Nacional de Residuos Orgánicos, la valorización de residuos orgánicos en Chile es menor al 1% (Ministerio del Medioambiente, 2020) y esta propone alcanzar metas sobre el 30% para el año 2030 y 60% para el año 2060. La biodigestión anaeróbica es un tratamiento biológico versátil que permite la valorización de residuos orgánicos en origen mediante su conversión en biogás y fertilizantes bio basados. Este tratamiento requiere de ambientes libres de oxígeno y su rendimiento depende de la salud de un consorcio de bacterias que, a su vez, dependen de parámetros de operación tales como la temperatura y el pH. En Chile existen más de 100 biodigestores rurales instalados que no cuentan con sistema de monitoreo. A nivel industrial, existen 107 plantas de biodigestión certificadas ante la Superintendencia de Electricidad y Combustibles (MinEnergía, 20217), actualmente, aproximadamente el 40% sigue operativa. Lo anterior da cuenta de la necesidad de contar con mayores de herramientas para la gestión eficiente de residuos orgánicos y de generar la capacidad para mantener estas soluciones de forma sostenible en el tiempo. Considerando esta problemática, se propuso un trabajo que realice una prueba empírica en condiciones reales, mediante el diseño e implementación de un sistema de micro biodigestión anaeróbica sensorizado y el posterior el análisis de los datos recolectados y de la composición del biol. Este trabajo describe el diseño de un sistema modular de micro biodigestión y un sistema de monitoreo de parámetros fisicoquímicos (pH y temperatura) que visibiliza los parámetros de operación en tiempo real. El sistema completo se implementó y probó en una localidad de Pozo Almonte, una de las zonas extremas del norte grande de Chile. El proyecto operó durante aproximadamente 12 meses, se tomaron muestras de biol bimensuales, que permitieron caracterizar el digestato o bioinsumo generado, mediante el análisis de laboratorio, evaluando parcialmente su contenido de nutrientes, metales pesados y la presencia de patógenos, con el propósito de para validar sus propiedades como fertilizante orgánico, según la Norma de Digestatos (MMA, 2015). Los resultados de producción de bioinsumos del biodigestor a escala rural con sistema de monitoreo, demostraron la viabilidad del sistema modular de biodigestión y su capacidad para operar en condiciones extremas. Con una producción de 20 litros diarios, el análisis del biol producido mostró una eliminación del 92% de coliformes fecales en un tiempo de retención hidráulica de 40 días a temperaturas mesofílicas-psicrofílicas. El bioinsumo también contenía micronutrientes y macronutrientes esenciales para su uso como fertilizante, sin presencia de metales pesados.
Estrategia de gestión energética: optimización del sistema de almacenamiento para un caso de estudio utilizando hidrógeno verde y baterias
(Universidad del Desarrollo. Facultad de Ingeniería, 2022) Fernández Henríquez, Ignacio; Bosch, Paul; Reyes Bozo, Lorenzo
Este trabajo presenta una propuesta para optimizar un sistema de almacenamiento que utiliza hidrógeno verde de una manera no convencional en Chile. El objetivo de esta investigación es implementar una estrategia de gestión energética a través de un modelo matemático para la optimización de un sistema de almacenamiento de energía que utiliza hidrógeno verde y baterías, el cual, permite abastecer el consumo eléctrico de una demanda real para un caso de estudio en la ciudad de Calama. Para lograrlo se propone una aproximación cuantitativa, utilizando un modelo matemático que considera como datos de entrada condiciones climáticas y demanda energética, evaluado para cada estación dentro de un rango de una semana, codificado en AMPL y resuelto con CPLEX. Los datos muestran que, al implementar el modelo matemático, es posible abastecer la demanda eléctrica en su totalidad utilizando hidrógeno verde y baterías. En síntesis, es posible asegurar que la estrategia permite el uso correcto de los recursos, en base a la irradiación solar y la demanda, utilizando baterías e hidrógeno verde en diferentes proporciones según cada estación del año, demostrando una fuerte inclinación del uso de baterías y celda de combustible durante invierno y otoño.
Feasibility and Cost Minimisation for a Lithium Extraction Problem
(2019) Bosch, Paul; Contreras, J.P.; Saavedra-Rosas, J.
In this paper we address the problem of allocating extraction pumps to wells, when exploiting lithium rich brines, as part of the production of lithium salts. The problem of choosing the location of extraction wells is defined using a transportation network structure. Based on the transportation network, the lithium rich brines are pumped out from each well and then mixed into evaporation pools. The quality of the blend will be based on the chemical concentrations of the different brines, originating from different wells. The objective of the problem is then to determine a pumping plan such that the final products have predefined concentrations, and the process is operated in the cheapest possible way. The problem is modelled as a combinatorial optimisation problem and a potential solution to it is sought using a genetic algorithm. The evaluation function of the genetic algorithm needs a method to determine feasible minimum cost flows for the proposed pumping alloca- tion, thus requiring the formulation of a blending model in a flow network for which a new iterative non-convex local optimisation algorithm is proposed. The model was implemented and tested to measure the algorithm’s efficiency.
Generalized inequalities involving fractional operators of the Riemann-Liouville type
(2021) Bosch, Paul; Carmenate, Héctor; Rodríguez, José Manuel; Sigarreta, José María
In this paper, we present a general formulation of the well-known fractional drifts of Riemann-Liouville type. We state the main properties of these integral operators. Besides, we study Ostrowski, Szekely-Clark-Entringer and Hermite-Hadamard-Fej ´ er inequalities involving these general fractional operators.
Inequalities on the Generalized ABC Index
(2021) Bosch, Paul; Molina, Edil D.; Rodríguez, José Manuel; Sigarreta, José María
In this work, we obtained new results relating the generalized atom-bond connectivity index with the general Randi´c index. Some of these inequalities for ABCα improved, when α = 1/2, known results on the ABC index. Moreover, in order to obtain our results, we proved a kind of converse Hölder inequality, which is interesting on its own.
Jensen-type inequalities for m-convex functions
(2022) Bosch, Paul; Quintana, Yamilet; Rodríguez, José M.; Sigarreta, José M.
Inequalities play an important role in pure and applied mathematics. In particular, Jensen’s inequality, one of the most famous inequalities, plays the main role in the study of the existence and uniqueness of initial and boundary value problems for differential equations. In this work, we prove some new Jensen-type inequalities for m-convex functions and apply them to generalized Riemann-Liouvilletype integral operators. Furthermore, as a remarkable consequence, some new inequalities for convex functions are obtained.
Mining EEG with SVM for Understanding Cognitive Underpinnings of Math Problem Solving Strategies
(2018) Bosch, Paul; Herrera, Mauricio; López, Julio; Maldonado, Sebastián
We have developed a new methodology for examining and extracting patterns from brain electric activity by using data mining and machine learning techniques. Data was collected from experiments focused on the study of cognitive processes that might evoke different specific strategies in the resolution of math problems. A binary classification problem was constructed using correlations and phase synchronization between different electroencephalographic channels as characteristics and, as labels or classes, the math performances of individuals participating in specially designed experiments. The proposed methodology is based on using well-established procedures of feature selection, which were used to determine a suitable brain functional network size related to math problem solving strategies and also to discover the most relevant links in this network without including noisy connections or excluding significant connections
Modeling the Spread of Tuberculosis in Semiclosed Communities
(2013) Herrera, Mauricio; Bosch, Paul; Nájera, Manuel; Aguilera, Ximena
We address the problem of long-term dynamics of tuberculosis (TB) and latent tuberculosis (LTB) in semiclosed communities. These communities are congregate settings with the potential for sustained daily contact for weeks, months, and even years between their members. Basic examples of these communities are prisons, but certain urban/rural communities, some schools, among others could possibly fit well into this definition. These communities present a sort of ideal conditions for TB spread. In order to describe key relevant dynamics of the disease in these communities, we consider a five compartments SEIR model with five possible routes toward TB infection: primary infection after a contact with infected and infectious individuals (fast TB), endogenous reactivation after a period of latency (slow TB), relapse by natural causes after a cure, exogenous reinfection of latently infected, and exogenous reinfection of recovered individuals. We discuss the possible existence of multiple endemic equilibrium states and the role that the two types of exogenous reinfections in the long-term dynamics of the disease could play
On new Milne-type inequalities and applications
(2023) Bosch, Paul; Sigarreta, José M.; RODRIGUEZ GARCIA, JOSE MANUEL
Inequalities play a major role in pure and applied mathematics. In particular, the inequality plays an important role in the study of Rosseland’s integral for the stellar absorption. In this paper we obtain new Milne-type inequalities, and we apply them to the generalized Riemann–Liouville-type integral operators, which include most of the known Riemann–Liouville integral operators.
On Ostrowski Type Inequalities for Generalized Integral Operators
(2022) Cruz, Martha Paola; Abreu-Blaya, Ricardo; Bosch, Paul; Rodríguez, José M.; Sigarreta, José M.
It is well known that mathematical inequalities have played a very important role in solving both theoretical and practical problems. In this paper, we show some new results related to Ostrowski type inequalities for generalized integral operators.
On the Generalized Laplace Transform
(2021) Bosch, Paul; Carmenate García, Héctor José; Rodríguez, José Manuel; Sigarreta, José María
In this paper we introduce a generalized Laplace transform in order to work with a very general fractional derivative, and we obtain the properties of this new transform. We also include the corresponding convolution and inverse formula. In particular, the definition of convolution for this generalized Laplace transform improves previous results. Additionally, we deal with the generalized harmonic oscillator equation, showing that this transform and its properties allow one to solve fractional differential equations.
On the Inverse Degree Polynomial
(2019) Bosch, Paul; Rodríguez, José Manuel; Rosario, Omar; Sigarreta, José María
Using the symmetry property of the inverse degree index, in this paper, we obtain several mathematical relations of the inverse degree polynomial, and we show that some properties of graphs, such as the cardinality of the set of vertices and edges, or the cyclomatic number, can be deduced from their inverse degree polynomials.
On the variable inverse sum deg index
(2023) Molina, Edil D.; Bosch, Paul; Sigarreta, José M.; Tourís , Eva
Several important topological indices studied in mathematical chemistry are expressed in the following way , where is a two variable function that satisfies the condition , denotes an edge of the graph and is the degree of the vertex . Among them, the variable inverse sum deg index , with , was found to have several applications. In this paper, we solve some problems posed by Vukičević [1], and we characterize graphs with maximum and minimum values of the index, for , in the following sets of graphs with vertices: graphs with fixed minimum degree, connected graphs with fixed minimum degree, graphs with fixed maximum degree, and connected graphs with fixed maximum degree. Also, we performed a QSPR analysis to test the predictive power of this index for some physicochemical properties of polyaromatic hydrocarbons.
Oscillation results for a nonlinear fractional differential equation
(2023) Bosch, Paul; Rodríguez, José M.; Sigarreta, José M.
In this paper, the authors work with a general formulation of the fractional derivative of Caputo type. They study oscillatory solutions of differential equations involving these general fractional derivatives. In particular, they extend the Kamenev-type oscillation criterion given by Baleanu et al. in 2015. In addition, we prove results on the existence and uniqueness of solutions for many of the equations considered. Also, they complete their study with some examples.
Preconditioning of adipose tissue-derived mesenchymal stem cells with deferoxamine increases the production of pro-angiogenic, neuroprotective and anti-inflammatory factors: Potential application in the treatment of diabetic neuropathy
(PLoS, 2017) Oses, Carolina; Olivares, Belen; Ezquer, Marcelo; Acosta, Cristian; Bosch, Paul; Donoso, Macarena; Leniz, Patricio; Ezquer, Fernando
Diabetic neuropathy (DN) is one of the most frequent and troublesome complications of diabetes mellitus. Evidence from diabetic animal models and diabetic patients suggests that reduced availability of neuroprotective and pro-angiogenic factors in the nerves in combination with a chronic pro-inflammatory microenvironment and high level of oxidative stress, contribute to the pathogenesis of DN. Mesenchymal stem cells (MSCs) are of great interest as therapeutic agents for regenerative purposes, since they can secrete a broad range of cytoprotective and anti-inflammatory factors. Therefore, the use of the MSC secretome may represent a promising approach for DN treatment. Recent data indicate that the paracrine potential of MSCs could be boosted by preconditioning these cells with an environmental or pharmacological stimulus, enhancing their therapeutic efficacy. In the present study, we observed that the preconditioning of human adipose tissue-derived MSCs (AD-MSCs) with 150μM or 400μM of the iron chelator deferoxamine (DFX) for 48 hours, increased the abundance of the hypoxia inducible factor 1 alpha (HIF-1α) in a concentration dependent manner, without affecting MSC morphology and survival. Activation of HIF-1α led to the up-regulation of the mRNA levels of pro-angiogenic factors like vascular endothelial growth factor alpha and angiopoietin 1. Furthermore this preconditioning increased the expression of potent neuroprotective factors, including nerve growth factor, glial cell-derived neurotrophic factor and neurotrophin-3, and cytokines with anti-inflammatory activity like IL4 and IL5. Additionally, we observed that these molecules, which could also be used as therapeutics, were also increased in the secretome of MSCs preconditioned with DFX compared to the secretome obtained from non-preconditioned cells. Moreover, DFX preconditioning significantly increased the total antioxidant capacity of the MSC secretome and they showed neuroprotective effects when evaluated in an in vitro model of DN. Altogether, our findings suggest that DFX preconditioning of AD-MSCs improves their therapeutic potential and should be considered as a potential strategy for the generation of new alternatives for DN treatment.

Browsing by Author "Bosch, Paul"

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