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Gerard Olivar Tost

Gerard Olivar Tost
University of Aysen · Natural Sciences & Technology

Ph.D. in Applied Mathematics
Research Director at University of Aysen

About

214
Publications
38,157
Reads
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2,420
Citations
Introduction
My research interest lies in the contribution of differential equations (ODEs and PDEs) in the framework of Applied Statistics and GIS (Geographical Information Systems). With my team, I try to envision some scenarios for the evolution of nature (mainly water and forest) and human settlements in the Aysen region in Chile. We have research activities close to engineers and scientists, to achieve full understanding. Our aim is to provide good information to decision makers.
Additional affiliations
August 2019 - present
Universidad de Aysén
Position
  • Chair
September 2005 - December 2010
Universidad Nacional de Colombia
Position
  • Professor (Full)
October 1987 - September 2005
Universitat Politècnica de Catalunya
Position
  • Universitat Politécnica de Catalunya
Education
October 1993 - July 1997
October 1981 - July 1987

Publications

Publications (214)
Article
Full-text available
This research proposes a methodology for evaluating and prioritizing green projects based on an integrated approach between system dynamics modeling and the analytical network process. The methodology is presented in three stages: First of all, we show the citizen factors and obtain the data from the zone through community participation. Then, in t...
Preprint
Citizen participation has always been of vital importance in decision-making processes and, likewise, joint work in the formulation and execution of projects that respond to territorial needs. This in order to ensure the best impact of public or private investment, optimizing the result and community articulation. For this reason, this investigatio...
Article
Full-text available
Nonpharmaceutical interventions (NPI) such as banning public events or instituting lockdowns have been widely applied around the world to control the current COVID-19 pandemic. Typically, this type of intervention is imposed when an epidemiological indicator in a given population exceeds a certain threshold. Then, the nonpharmaceutical intervention...
Article
Full-text available
The concept of Sustainable Development has given rise to multiple interpretations. In this article, it is proposed that Sustainable Development should be interpreted as the capacity of territory, community, or landscape to conserve the notion of well-being that its population has agreed upon. To see the implications of this interpretation, a Brande...
Article
Full-text available
The Coffee Berry Borer (CBB) is the main pest that affects coffee crops around the world, causing major economic losses and diminishing beverage quality. A mathematical model is formulated, from the perspective of the Adaptive Dynamics (AD) framework, to describe the evolution of coffee quality as a continuous differentiating attribute related to t...
Article
The watersheds of the Quindío River in Colombia South America have high levels of contamination by total suspended solids (TSS). The objective of this work was to represent the entire hydrographic network of the watersheds of the Quindío department by means of a graph and, using network theory, analyze the different centrality measures to identify...
Chapter
Tourism is not only a source of wealth, but also a positive way of knowing and mixing local and foreign cultures. However, overexploitation of natural resources and inadequate behaviours (among other factors) can lead to a conflict between tourists and locals that makes the tourist economy not sustainable. The modelling of tourist flows is a good t...
Article
A new study of the Buck converter controlled by a smooth signal -changing the widely used non-smooth ramp signal by a smooth sine signal- operating in continuous conduction mode (CCM) is carried out in this paper, focusing on the analysis of bifurcation diagrams of relevant parameters that govern the system. Unexpectedly and contrary to what one wo...
Article
Full-text available
This research article presents the integration of participatory modeling and system dynamics as a novel methodology for the consolidation of social dynamic models for the subsequent evaluation and prioritization of green projects in Colombian post-conflict communities. First, through participatory work carried out with a community, the citizen fact...
Preprint
Full-text available
Nonpharmaceutical interventions (NPI) such as banning public events or instituting lockdowns have been widely applied around the world to control the current COVID-19 pandemic. Typically, this type of intervention is imposed when an epidemiological indicator in a given population exceeds a certain threshold. Then, the nonpharmaceutical intervention...
Article
The main objective of this research study is to model the equilibria in the separation of butanol using the extractant 2-ethyl-1-hexanol (2E1H). Binary parameters were fitted using MATLAB’s default genetic algorithm function and a solver for nonlinear curve-fitting (‘lsqcurvefit’). The products assessed in the ternary equilibria were ethanol, butan...
Article
Full-text available
This paper reports a general model that describes the supply and demand of electricity in a national market based on the system dynamics (SD) approach. From the resulting SD model, it derives piecewise smooth (non-smooth) differential equations from the nonlinear functions and feedback cycles of the corresponding stock-flow structure. Subsequently,...
Article
The acetone-butanol-ethanol (ABE) fermentation from corn stover was considered. We propose, study and optimise, via process simulation (using MATLAB® and Aspen Plus®) the use of fermentation tanks-in-series and in situ product recovery by vacuum evaporation. As the operating time of continuous fermentation processes is usually limited at less than...
Article
Full-text available
Autor a quien debe ser dirigida la correspondencia Resumen El butanol es un biocombustible con más alta densidad energética que el etanol y por tanto con alto interés. El extractante 2-etil-1-hexanol es uno de los solventes más interesantes para la separación de butanol por su alto coeficiente de distribución y selectividad. Con el objetivo de simu...
Article
Full-text available
En este trabajo, se evaluó la producción de butanol por fermentación en una operación de vacío cíclica con múltiples alimentaciones de sustrato a través de una estrategia de simulación de procesos. La sacarificación del sustrato, rastrojo de maíz, fue simulada en un reactor integrado con fermentación y recuperación in situ de producto. Para esta ev...
Article
Full-text available
In several open and closed-loop systems, the trajectories converge to a region instead of an equilibrium point. Identifying the convergence region and proving the asymptotic convergence upon arbitrarily large initial values of the state variables are regarded as important issues. In this work, the convergence of the trajectories of a biological pro...
Article
Full-text available
Tree of Science (ToS) is a web-based tool which uses the network structure of paper citation to identify relevant literature. ToS shows the information in the form of a tree, where the articles located in the roots are the classics, in the trunk are the structural publications, and leaves are the most current papers. It has been found that some res...
Article
Full-text available
A mathematical model for international integration of national energy markets was proposed by references. Lowering the dimension conveniently to 3 dimensions using system dynamics methodology, the dynamical system obtained could present a commutation region proposing that the system is a piecewise smooth system PWS with local bifurcations: Saddle-n...
Article
Full-text available
In this study, a mathematical model is formulated and studied from the perspective of adaptive dynamics (evolutionary processes), in order to describe the interaction dynamics between two city public transport systems: one of which is established and one of which is innovative. Each system is to be influenced by a characteristic attribute; in this...
Conference Paper
Debido a la necesidad de viabilizar la producción sostenible de biocombustibles, optimización de tecnologías intensificadas es necesaria. En este trabajo, se simuló y evaluó en la producción de butanol a vacío por fermentación la necesidad de utilizar una operación de vacío cíclica y múltiples alimentaciones en un sistema de reacción con recuperaci...
Conference Paper
El butanol es un bicombustible con más alta densidad energética que el etanol y por tanto con alto interés. Sin embargo, su producción biotecnológica está limitada por la alta toxicidad del butanol al microorganismo que lo produce. Una alternativa para mejorar su producción es mediante el uso de reactores con extracción in situ. Entre los extractan...
Chapter
In Colombia, there are reports of regions which have reached minimum natural resource thresholds. Among of the main causes thereof is the absence of institutional control actions. This absence is reflected in high rates of deforestation, water pollution, famine, and poverty, to name a few. For example, in La Guajira, a region where emeralds, coal,...
Article
A methodology for the modeling of business sustainability that is based on the dynamics of systems and integrating elements of mathematical, statistical and dynamic systems analysis is proposed. For this, the general aspects referring to sustainable development are reviewed. Among this are, the characteristics and indicators related to sustainable...
Article
Full-text available
To reduce the energy consumption in buildings is necessary to analyze individual rooms and thermal zones, studying mathematical models and applying new control techniques. In this paper, the design, simulation and experimental evaluation of a sliding mode controller for regulating internal temperature in a thermal zone is presented. We propose an e...
Article
Full-text available
In this paper, we present a piecewise smooth system, that describes thedynamics of a single vehicle moving through a street that has a sequence oflights that turn on and off with a specific frequency. The model presentsthree dynamic ways: accelerated, decelerated and zero state. Besides,we show the description of the mathematical model used to simu...
Article
Full-text available
Reliable and robust control of power converters is a key issue in the performance of numerous technological devices. In this paper we show a design technique for the control of a DC-DC buck converter with a switching technique that guarantees both good performance and global stability. We show that making use of the contraction theorem in the Jorda...
Article
Full-text available
In this paper, we show the preliminary results in a proposed a model for the supply and demand of electricity in a domestic market based on system dynamics. Additionally, the model indicates piecewise smooth differential equations arising from the diagram of flows and levels, using dynamical systems theory for the study of the stability of the equi...
Article
Full-text available
The biofuels industry has grown and has positioned itself in Colombia for national purposes, these come from biomass sources such as agricultural crops. Bioethanol is the most used in Colombia and is obtained from sugarcane. One of the main concerns of the sector and society, is the high water consumption associated with agricultural crops (9,000 m...
Article
Full-text available
Historical civilizations have evidenced different routes to the collapse mainly due to political, warfare, cultural and environmental damages. This has animated modern researches to study and understand social, economic, and environmental challenges that modern societies must adopt in order to avoid history from repeat itself, and even worst, irrev...
Article
Full-text available
This article presents preliminary results of the mathematical analysis of a national energy market. The modeling of the studied system was made from causal relationships between the supply and demand of a national energy market, obtaining a system of ordinary differential equations of the first order of the electric power capacity in construction,...
Article
In this study, a mathematical model is formulated and studied from the perspective of adaptive dynamics (evolutionary processes), in order to describe the interaction dynamics between two city public transport systems: one of which is established and one of which is innovative. Each system is to be influenced by a characteristic attribute; in this...
Article
Full-text available
En este artículo se construye y evalúa un modelo de sostenibilidad empresarial para una industria manufacturera en el cual se incorporan indicadores del desarrollo sostenible. La construcción y el análisis del modelo se basa en la metodología de dinámica de sistemas. En esta metodología se parte de la caracterización de la sostenibilidad empresaria...
Preprint
Full-text available
Reliable and robust control of power converters is a key issue in the performance of numerous technological devices. In this paper we show a design technique for the control of a DC-DC buck converter with a switching technique that guarantees not only good performance but also global stability. We show that making use of the contraction theorem in...
Chapter
The performance of the agricultural sector is considered a fundamental factor for achieving sustainability of the most vulnerable population as well to meet the world’s food needs. This is how countries like Colombia, recognize in their government plans the importance of the development of sector leveraged by infrastructures boosting their results,...
Chapter
The agricultural sector is a strategic source for the sustenance of the population worldwide, however, given the lack of a favourable environment that guarantees its sustainability and growth, this sector is exposed to multiple conflicts and needs, which affect its performance and even causing desertion of the producer. In this research, we model a...
Article
Full-text available
We study a mathematical model based on ordinary differential equations to describe the dynamic interaction in the market of two types of energy called standard and innovative. The model consists of an adaptation of the generalized Lotka-Volterra system in which the parameters are assumed to depend on a quantitative and continuous attribute characte...
Article
A numerical method for the analysis of the behavior of two dynamic systems with multiple stationary states is presented. Two reactive chemical systems of industrial interest were studied: the isocyanate hydrolysis and the acetic anhydride hydrolysis. The simulation was implemented in the Matlab® software using cell-mapping. Stability and multiple s...
Article
A numerical method for the analysis of the behavior of two dynamic systems with multiple stationary states is presented. Two reactive chemical systems of industrial interest were studied: the isocyanate hydrolysis and the acetic anhydride hydrolysis. The simulation was implemented in the Matlab® software using cell-mapping. Stability and multiple s...
Article
Full-text available
The article presents the stochastic modeling of a particular dynamic of dengue cases for a constant population with an initial number of susceptible and infected members, a time-dependent force of infection and a probability-generating function from which a linear partial differential equation (PDE) of first order is derived whose solution can assi...
Article
Full-text available
En este artículo se presenta un modelo matemático y la evaluación de distintos escenarios de la estimación de la tendencia del consumo de agua en el proceso productivo del bioetanol en Colombia. El modelo fue establecido con la metodología de dinámica de sistemas, la cual permitió representar las principales variables de la cadena de producción de...
Article
Full-text available
The inhibitors produced in the pretreatment (phenolics, furans, and organic acids) as well as in the fermentation (butanol and organic acids) limit acetone, butanol, and ethanol (ABE) production from lignocellulose. To reduce their negative impact on the fermentation, a process involving simultaneous saccharification, ABE fermentation, and detoxifi...
Article
Full-text available
The regional integration of electricity markets has been established as desirable among the South American nations to meet demands through the possible consolidation of a unified competing market in the medium term (CAN, 2010). However, what remains to be defined are rules of the game with satisfactory benefits for all parties that have been demons...
Article
Full-text available
Acetone, butanol, and ethanol (ABE) is an alternative biofuel. However, the energy requirement of ABE recovery by distillation is considered elevated (> 15.2 MJ fuel/Kg-ABE), due to the low concentration of ABE from fermentation broths (between 15 and 30 g/l). In this work, to reduce the energy requirements of ABE recovery, four processes of heat-i...
Article
Full-text available
En este artículo se presenta la descripción del problema de sostenibilidad que enfrentan los sistemas de producción de biocombustibles, en específico la producción de bioetanol en Colombia, desde una preceptiva sistémica desarrollada por medio de diagramas causales del problema. Para comprender la sostenibilidad de la bioenergía y los biocombustibl...
Article
Full-text available
Discussion about project management, in both the academic literature and industry, is predominantly based on theories of control, many of which have been developed since the 1950s. However, issues arise when these ideas are applied unilaterally to all types of projects and in all contexts. In complex environments, management problems arise from ass...
Chapter
In the pretreatment of lignocellulose several compounds are produced (organic acids, furans, and phenolic compounds). Butanol and inhibitors from pretreatment (IFP) are highly toxic for the microorganisms process of ABE fermentation. For this reason, ABE production from lignocellulose in a simultaneous saccharification, fermentation, and detoxifica...
Article
We present a system of ordinary nonlinear differential equations describing the population growth dynamics of the Aedes aegypti mosquito, the main transmitter of the dengue virus in Colombia. This model incorporates the three types of known control for mosquito eradication: mechanical, biological and chemical, focusing on biological control through...
Article
Full-text available
De acuerdo a referencias, existe una fuerte influencia del estrés con el desarrollo de enfermedades. En este trabajo se consideraron los atributos que hacen posible esa influencia para la elaboración de un modelo matemático que permite el planteamiento de escenarios que cambian con la frecuencia con la que un individuo implementa soluciones tempora...
Technical Report
Full-text available
Se desarrolló una ecuación para la selección de membranas para un proceso de pervaporación en función de la permeabilidad y de la selectividad. El método corto fue generado a partir de la simulación y optimización rigurosa de un esquema híbrido de pervaporación, sacarificación y fermentación ABE (acetona, butanol y etanol). El reactor propuesto lim...
Article
Full-text available
En este artículo se analiza el comportamiento local y global de un sistema dinámico suave a trozos en dos variables, estudiando el flujo de dos sistemas dinámicos lineales no homogéneos que conmutan con las fronteras de una banda de histéresis. Analíticamente se determinan las soluciones de equilibrio y los dominios paramétricos que garantizan la e...
Article
Full-text available
According to literature, there is a strong influence of stress with the emergence of diseases. In this paper the attributes that make possible this influence in order to develop a mathematical model that allows the approach of scenarios that change with the frequency an individual implements temporary solutions to deal with stress (pseudosolutions)...
Chapter
This short paper proposes a general economics model for the supply and demand of a commodity in a domestic market, when investments are required for supporting it. Starting from System Dynamics, we recover a well-known model. Then, we improve the mathematical equations in order to be precise at the simulation level.
Article
A fast and accurate determination of voltage stability weak areas allows the power system operator to execute preventive actions, aimed to maintain an adequate operation under changing conditions. However, due to the large number of possible power system operating conditions, the determination of weak areas becomes a challenging task. This paper is...
Article
Full-text available
Background Dual extraction, high-temperature extraction, mixture extraction, and oleyl alcohol extraction have been proposed in the literature for acetone, butanol, and ethanol (ABE) production. However, energy and economic evaluation under similar assumptions of extraction-based separation systems are necessary. Hence, the new process proposed in...
Article
Full-text available
In the this paper, we show a methodological summary to simulate and understand the complex behavior of energy market models. The goal of this work is to propose the business approach of system dynamics, with the dynamical systems and its mathematical point of view. Additionally we present two ways to perform sensitivity analysis on models based on...
Article
Full-text available
In this paper, we show a methodological summary to simulate and understand the complex behavior of energy market models. The goal of this work is to propose the business approach of system dynamics, with the dynamical systems and its mathematical point of view. Additionally, we present two ways to perform sensitivity analysis on models based on sys...