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https://hdl.handle.net/10784/1512

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Adaptive System for the Generation of Emerging Behaviors in Serious Emerging Games
(Instituto Politecnico Nacional, 2020-01-01) Aguilar, Jose; Altamiranda, Junior; Diaz, Francisco; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
A video game adaptation system (SAV) for serious emergent games (JSE), allows emergent behaviors in the game, such as the appearance of environments, events, narratives and characters, among others, in order to adapt to the context in the one that is developing. In previous articles the architecture of a JSE engine has been proposed. Furthermore, a first subsystem has been proposed that allows the emergence of a JSE according to the objectives of the environment, based on the ant colony optimization algorithm (ACO). In the present work, the second component of said architecture is specified, the SAV, which allows its dynamic adaptation (during the JSE). The SAV is made up of the sub-layers of strategies, sequences and properties, which manage each of these types of possible emergencies in a JSE, with the intention of dynamically adapting it to the context-domain where the game is being played. Furthermore, in this work the behavior of these sublayers is analyzed in a specific case study, showing very encouraging results of SAV in the educational context of an intelligent classroom (SaCI).
Airline choice model for an international round-trip flight considering outbound and return flight schedules
(Warsaw University of Technology, 2020-01-01) Munoz C.; Laniado H.; Córdoba J.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
This paper quantified the impact of outbound and return flight schedule preferences on airline choice for international trips. Several studies have used airline choice data to identify preferences and trade-offs of different air carrier service attributes, such as travel time, fare and flight schedule. However, estimation of the effect return flight schedules have on airline choice for an international round-trip flight has not yet been studied in detail. Therefore, this study introduces attributes related to return flight characteristics and round-trip flight schedule interaction into the airline choice models, which have not previously been reported in the literature. We developed a stated preference survey that includes round-trip fares based on flight schedule combinations and the number of days prior to departure fares was purchased. We applied modelling techniques using a set of stated preference data. A mixed logit model was tested for the presence of heterogeneity in passengers' preferences. Our results indicated that models with attributes related to return flight and its interaction with outbound flight attributes have a superior fit compared with models only based on attributes reported in the literature review. The model found shows that airfare, travel time, arrival preference schedule in the outward journey, departure preference in the return journey and the schedule combination of round-trip flight are significantly affecting passenger choice behaviour in international round-trip flights. Sensitivity analysis of airline service characteristics and their marketing implications are conducted. The analysis reports seven policies with the greatest impact on each airline choice probabilities. It shows that by reducing travel time and airfare and by adopting an afternoon and night schedule preference for outbound and return flight, respectively, the highest probability on airline choice would be reached. This research contributes to the current literature by enhancing the understanding of how passengers choose airlines, considering both outbound and inbound journey characteristics. Thus, this study provides an analytical tool designed to provide a better understanding of international round-trip flight demand determinants and support carrier decisions. © 2020 Warsaw University of Technology. All rights reserved.
An alternative model to explain the vectorial capacity using as example Aedes aegypti case in dengue transmission
(Elsevier BV, 2019-01-01) Catano-Lopez A.; Rojas-Diaz D.; Laniado H.; Arboleda-Sánchez S.; Puerta-Yepes M.E.; Lizarralde-Bejarano D.P.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Vectorial capacity (VC), as a concept that describes the potential of a vector to transmit a pathogen, has had historical problems related to lacks in dimensional significance and high error propagation from parameters that take part in the model to output. Hence, values estimated with those equations are not sufficiently reliable to consider in control strategies or vector population study. In this paper, we propose a new VC model consistent at dimensional level, i.e., the definition and the equation of VC have same and consistent units, with a parameter estimation method and mathematical structure that reduces the uncertainty in model output, using as a case of study an Aedes aegypti population of the municipality of Bello, Colombia. After a literature review, we selected one VC equation following biological, measurability and dimensional criteria, then we rendered a local and global sensitivity analysis, identifying the mortality rate of mosquitoes as a target component of the equation. Thus, we studied the Weibull and Exponential distributions as probabilistic models that represent the expectation of mosquitoes infective life, intending to include the best distribution in a selected VC structure. The proposed mortality rate estimation method includes a new parameter that represents an increase or decrease in vector mortality, as it may apply. We noticed that its estimation reduces the uncertainty associated with the expectation of mosquitoes' infective life expression, which also reduces the output range and variance in almost a half. Virology; Applied mathematics; Health sciences; Epidemiology; Infectious disease; Mortality; Uncertainty analysis; Vectorial capacity; Sensitivity analysis; Dengue © 2019 The Authors
Anteversión pélvica como causa de dolor lumbar, síndrome patelofemoral y dolores del crecimiento
(Ediciones Doyma, S.L., 2014-01-01) Vélez-Patiño, J.A.; Ríos-Sánchez, L.M.; Ochoa-Jaramillo, F.L.; Díaz-León, C.A.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Introduction: Back pain, patellofemoral syndrome and "growing pains" are increasingly common in children and adolescents, both with incidence and precocity of appearance. In most cases their etiology is unknown. Objective: The objective of this research was to explore the possible association of these three entities with pelvic anteversion. Methods: This is a cross-sectional study with case-control analysis, comprising a group of 30 symptomatic children aged between 6 and 17 years (cases) who had consulted for low back pain, "growing pains" or sore knees, and a control group of 30 children with no history of pain in these areas (controls). To measure the position of the pelvis and other biomechanical variables a software programme was developed that quantifies these measurements from reflective markings located on specific anatomical landmarks of each child. Other measurements were obtained through semiological tests and interviews with children and their parents. Results: Children and adolescents with pain had more pelvic anteversion compared with controls (mean 13.3 and 5.4 degrees, p < 0.001). They also had less strength in muscles: Lumbar extensor, abdominals, psoas and diaphragm. We found that psoas is the muscle most responsible for pelvis anteversion in symptomatic group. Compared with children without pain, those with back pain, patellofemoral syndrome or "growing pains" have 4.2 times more frequent poor or regular strength in the column extensor muscles. They also have nearly 18 times as likely to have a pelvic angle greater than 10 degrees compared with no pain children. Conclusions: Children and adolescents who suffer from back pain, patellofemoral syndrome and "growing pains" have increased pelvic anteversion and lower muscle strength, mainly in the thoracolumbar spine extensors, abdominals, diaphragm and psoas. The study found that the psoas muscle is most responsible for the development of pelvis anteversion. Pelvic anteversion is associated with low back pain, patellofemoral pain syndrome and "growing pains". © 2015 Arán Ediciones, S.L.
Application of the continuous wavelet transform in the extraction of directional data on RTM imaging condition wavefields
(Ecopetrol, 2018-01-01) Paniagua-Castrillón J.-G.; Quintero-Montoya O.-L.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Low-frequency artifacts in reverse time migration result from unwanted cross-correlation of the source and receiver wavefields at nonreflecting points along ray-paths. These artifacts can hide important details in migrated models and increase poor interpretation risk. Some methods have been proposed to avoid or reduce the number of these artifacts, preserving reflections, and improving model quality, implementing other strategies such as modification of the wave equation, proposing other imaging conditions, and using image filtering techniques. One of these methods uses wavefield decomposition, correlating components of the wavefields that propagate in opposite directions. We propose a method for extracting directional information from the RTM imaging condition wavefields to obtain characteristics allowing for better, more refined imaging. The method works by separating directional information about the wavefields based on the continuous wavelet transform (CWT), and the analysis of the main changes on the frequency content revealed within the scalogram obtained by a Gaussian wavelet family. Through numerical applications, we demonstrate that this method can effectively remove undesired artifacts in migrated images. In addition, we use the Laguerre-Gauss filtering to improve the results obtained with the proposed method. © 2018 Ecopetrol S.A. All Rights Reserved.
An approach to emotion Recognition in Single-channel EEG Signals using Stationary Wavelet Transform
(SPRINGER, 2017-04-01) MEJIA, GUSTAVO ANTONIO; QUINTERO, OLGA LUCIA; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
An approach to emotion recognition in single-channel EEG signals: a mother child interaction
(IOP Publishing, 2016) Gómez, A.; Quintero, L.; López, N.; Castro, J.; Gómez, A.; Quintero, L.; López, N.; Castro, J.; Mathematical Modeling Research Group, GRIMMAT, School of Sciences, Universidad EAFIT, Medellín, Colombia; Medical Technology Laboratory, Faculty of Engineering, Universidad Nacional de San Juan, Argentina; Psychology, Education and Culture Research Group Faculty of Social Science Politécnico Grancolombiano University Institution, Argentina; Universidad EAFIT. Escuela de Ciencias; agomez13@eafit.edu.co; oquinte1@eafit.edu.co; Modelado Matemático
In this work, we perform a first approach to emotion recognition from EEG single channel signals extracted in four (4) mother-child dyads experiment in developmental psychology -- Single channel EEG signals are analyzed and processed using several window sizes by performing a statistical analysis over features in the time and frequency domains -- Finally, a neural network obtained an average accuracy rate of 99% of classification in two emotional states such as happiness and sadness
arboles binomiales para la valoración de opciones sobre procesos derivados de la ecuacion diferencial estocástica autónoma
(Fondo Editorial Universidad EAFIT, 2010-12-01) Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Are neural networks able to forecast nonlinear time series with moving average components?
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2015-07-01) Cogollo, M.R.; Velásquez, J.D.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
In nonlinear time series forecasting, neural networks are interpreted as a nonlinear autoregressive models because they take as inputs the previous values of the time series. However, the use of neural networks to forecast nonlinear time series with moving components is an issue usually omitted in the literature. In this article, we investigate the use of traditional neural networks for forecasting nonlinear time series with moving average components and we demonstrate the necessity of formulating new neural networks to adequately forecast this class of time series. Experimentally we show that traditional neural networks are not able to capture all the behavior of nonlinear time series with moving average components, which leads them to have a low capacity of forecast. © 2015 IEEE.
Author Correction: Unsupervised Scalable Statistical Method for Identifying Influential Users in Online Social Networks (Scientific Reports, (2018), 8, 1, (6955), 10.1038/s41598-018-24874-2)
(Nature Publishing Group, 2019-01-01) Azcorra A.; Chiroque L.F.; Cuevas R.; Anta A.F.; Laniado H.; Lillo R.E.; Romo J.; Sguera C.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
The original version of this Article contained an error in Affiliation 3, which was incorrectly given as ‘Department of Mathematical Sciences, Universidad EAFIT, Universidad Nacional de Colombia, Medellín, Colombia’. The correct affiliation is listed below: Department of Mathematical Sciences, Universidad EAFIT, Medellín, Colombia This error has now been corrected in the HTML and PDF versions of the Article and in the accompanying Supplementary Material file. © 2019, The Author(s).
Behavior comparison for biomass observers in batch processes
(Wiley-Blackwell, 2013-06-18) Amicarelli, Adriana; Lucia Quintero M, O.; Di Sciascio, Fernando; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
On-line estimation of biomass concentration in batch biotechnological processes is an active area of research because normally, the biomass is the desired process product output, and also because it is necessary for control purposes to replace the unavail
Big data?: historia, definición, herramientas y aplicaciones en la industria
(2019-01-07) Toro, M.; Laniado, H.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Dan Ariely, profesor de psicología y economía de la Universidad de Duke, plantea que "El big data [en español, datos masivos] es como el sexo en la adolescencia: todo el mundo habla de ello, nadie sabe realmente cómo hacerlo, todos piensan que los demás
Cerebral Cortex Atlas of Emotional States Through EEG Processing
(SPRINGER, 2019-10-14) Gómez A.; Quintero O.L.; Lopez-Celani N.; Villa L.F.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
This paper addresses the cerebral cortex maps construction from EEG signals getting an information simplification method for an emotional state phenomenon description. Bi-dimensional density distribution of main signal features are identified and a comparison to a previous approach is presented. Feature extraction scheme is performed via windowed EEG signals Stationary Wavelet Transform with the Daubechies Family (1–10); nine temporal and spectral descriptors are computed from the decomposed signal. Recursive feature selection method based on training a Random forest classifier using a one-vs-all scheme with the full features space, then a ranking procedure via gini importance, eliminating the bottom features and restarting the entire process over the new subset. Stopping criteria is the maximum accuracy. The main contribution is the analysis of the resulting subset features as a proxy for cerebral cortex maps looking for the cognitive processes understanding from surface signals. Identifying the common location of different emotional states in the central and frontal lobes, allowing to be strong parietal and temporal lobes differentiators for different emotions. © 2020, Springer Nature Switzerland AG.
Collaborative Networked Virtual Surgical Simulators (CNVSS) Implementing Hybrid Client-Server Architecture: Factors Affecting Collaborative Performance
(MIT PRESS, 2015-01-01) Diaz, Christian; Trefftz, Helmuth; Quintero, Lucia; Acosta, Diego A.; Srivastava, Sakti; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Currently, surgical skills teaching in medical schools and hospitals is changing, requiring the development of new tools to focus on (i) the importance of the mentor's role, (ii) teamwork skills training, and (iii) remote training support. Collaborative Networked Virtual Surgical Simulators (CNVSS) allow collaborative training of surgical procedures where remotely located users with different surgical roles can take part in the training session. To provide successful training involving good collaborative performance, CNVSS should guarantee synchronicity in time of the surgical scene viewed by each user and a quick response time which are affected by factors such as users' machine capabilities and network conditions. To the best of our knowledge, the impact of these factors on the performance of CNVSS implementing hybrid client-server architecture has not been evaluated. In this paper the development of a CNVSS implementing a hybrid client-server architecture and two statistical designs of experiments (DOE) is described by using (i) a fractional factorial DOE and (ii) a central composite DOE, to determine the most influential factors and how these factors affect the collaboration in a CNVSS. From the results obtained, it was concluded that packet loss, bandwidth, and delay have a larger effect on the consistency of the shared virtual environment, whereas bandwidth, server machine capabilities, and delay and interaction between factors bandwidth and packet loss have a larger effect on the time difference and number of errors of the collaborative task.
Collaborative Networked Virtual Surgical Simulators (CNVSS): Factors Affecting Collaborative Performance
(MIT PRESS, 2013-01-01) Diaz, Christian; Trefftz, Helmuth; Quintero, Lucia; Acosta, Diego A.; Srivastava, Sakti; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Stand-alone and networked surgical simulators based on virtual reality have been proposed as a means to train surgeons in specific surgical skills with or without expert guidance and supervision. However, a surgical operation usually involves a group of medical practitioners who cooperate as team members. To this end, CNVSS have been proposed for the collaborative training of surgical procedures in which users with different surgical roles can take part in the training session. To be successful, these simulators should guarantee synchronicity, which requires (1) consistent viewing of the surgical scene and (2) a quick response time. These two variables are affected by factors such as users' machine capabilities and network conditions. As far as we know, the impact of these factors on the performance of CNVSS has not been evaluated. In this paper, we describe the development of CNVSS and a statistical factorial design of experiments (DOE) to determine the most important factors affecting collaboration in CNVSS. From the results obtained, it was concluded that delay, jitter, packet loss percentage, and processor speed have a major impact on collaboration in CNVSS.
Combining fuzzy, PID and regulation control for an autonomous mini-helicopter
(ELSEVIER SCIENCE INC, 2007-05-15) Sanchez, Edgar N.; Becerra, Hector M.; Velez, Carlos M.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
This paper reports on the synthesis of different flight controllers for an X-Cell mini-helicopter. They are developed on the basis of the most realistic mathematical model currently available. Two hybrid intelligent control systems, combining computational intelligence methodologies with other control techniques, are investigated. For both systems, Mamdani-type fuzzy controllers determine the set points for altitude/attitude control. These fuzzy controllers are designed using a simple rule base. The first scheme consists of conventional SISO PID controllers for z-position and roll, pitch and yaw angles. In the second scheme, two of the previous PID controllers are used for roll and pitch, and a linear regulator is added to control altitude and yaw angle. These control schemes mimic the action of an expert pilot. The designed controllers are tested via simulations. It is shown that the designed controllers exhibit good performance for hover flight and control positioning at slow speed. © 2006 Elsevier Inc. All rights reserved.
The continuous wavelet transform in the extraction of information from wavefields
(Sociedade Brasileira de Geofisica, 2019-08-19) Montoya O.L.Q.; Paniagua, Juan Guillermo; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Artifacts in reverse time migration (RTM) are low spatial frequency noise that appears due to the undesired correlation of head waves
Control and parameter estimation of a mini-helicopter robot using rapid prototyping tools
(World Scientific and Engineering Academy and Society (WSEAS) Press, 2006-01-01) Vélez S., C.M.; Agudelo, A.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
This paper shows the control and parameter estimation of a mini-helicopter robot using a rapid prototyping environment based on Matlab/Simulink. The parameter estimation task is facilitated by the availability of a block-based visual simulation model and its integration in a general Matlab environment, with the feasibility of use of many other tools. The environment is integrated by modules which use common Matlab tools (ground control station, linearization, parameter estimation, heuristic identification) and own modules developed specifically for simulation, state estimation and multirate control. An example is presented in a software-in-the-loop context, showing all possibilities of the software environment including supervisory, estimation, linearization, and control tasks.
Control based on numerical methods and recursive Bayesian estimation in a continuous alcoholic fermentation process
(2009-01-01) QUINTERO, OLGA LUCIA; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Control centers design for ergonomics and safety.
(IOS Press, 2012-01-01) Quintana L; Lizarazo C; Bernal O; Cordoba J; Arias C; Monroy M; Cotrino C; Montoya O; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
This paper shows the general design conditions about ergonomics and safety for control centers in the petrochemical process industry. Some of the topics include guidelines for the optimized workstation design, control room layout, building layout, and lighting, acoustical and environmental design. Also takes into account the safety parameters in the control rooms and centers design. The conditions and parameters shown in this paper come from the standards and global advances on this topic on the most recent publications. And also the work was supplemented by field visits of our team to the control center operations in a petrochemical company, and technical literature search efforts. This guideline will be useful to increase the productivity and improve the working conditions at the control rooms.

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