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  • Ítem
    Memories Webinar "A dark cloud rises in the sky: meet SIATA, a system for environmental management"
    (Universidad EAFIT, 2024) Maria Eugenia Puerta-Yepes; Camilo García-Duque; Luz Jeannette Mejia-Chavarriaga; Daniel Ruiz-Carrascal; Universidad EAFIT
    Memories of the conference in Spanish. If a strong storm is approaching, as in the song of the Golden Binomial, or a ravine is rising, or if air pollutants represent a risk to your health, SIATA warns you. But Do you know how the Aburrá Valley Early Warning System - SIATA works? Within the framework of #COP16 we want to highlight the role of this system that generates, translates, transfers and disseminates alerts for environmental management and timely action by citizens throughout the Aburrá Valley. This project of the Metropolitan Area of ​​the Aburrá Valley finds its strategic academic ally in the Directorate of Innovation and Technological Development of EAFIT, which puts at the service of citizens all the capacity for generating new knowledge, technological development and social innovation of our academic community.
  • Ítem
    Memories Webinar "A dark cloud rises in the sky: meet SIATA, a system for environmental management"
    (Universidad EAFIT, 2024) Maria Eugenia Puerta-Yepes; Camilo García-Duque; Luz Jeannette Mejia-Chavarriaga; Daniel Ruiz-Carrascal; Universidad EAFIT
    Memories of the conference in English. If a strong storm is approaching, as in the song of the Golden Binomial, or a ravine is rising, or if air pollutants represent a risk to your health, SIATA warns you. But Do you know how the Aburrá Valley Early Warning System - SIATA works? Within the framework of #COP16 we want to highlight the role of this system that generates, translates, transfers and disseminates alerts for environmental management and timely action by citizens throughout the Aburrá Valley. This project of the Metropolitan Area of ​​the Aburrá Valley finds its strategic academic ally in the Directorate of Innovation and Technological Development of EAFIT, which puts at the service of citizens all the capacity for generating new knowledge, technological development and social innovation of our academic community.
  • Publicación
    InCyTo: Herramienta para la enseñanza del inventario de ciclo en cursos de Gestión Logística
    (Latin American and Caribbean Consortium of Engineering Institutions, 2017-01-01) Castro Zuluaga C.A.; Mendoza Vásquez C.; Gallego Roch L.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    One of the areas that requires greater attention within a company, it is the one responsible for the management of inventories, which are considered as a current asset that will affect positively or negatively the competitiveness of any organization. This is one of the reasons why in the courses of Logistics Management the issue of inventory management is very important, since it seeks to develop in students the ability to improve the decision-making process to define the quantity and the frequency of the orders of every stock keeping unit (skus). This article presents InCyTo (Inventory Cycle Simulation Tool), a tool designed and developed in Excel VBA® (Visual Basic for Applications), whose objective is to support the teaching-learning process of the topic of cycle inventory where the student will be able to test from the experimentation how the quantity and frequency of the orders affect the costs and the service, levels as well as to be able to understand and put into practice the concepts of the economic order quantity of the order, all through an active learning approach. © 2017 Latin American and Caribbean Consortium of Engineering Institutions. All rights reserved.
  • Publicación
    A variable block insertion heuristic for permutation flowshops with makespan criterion
    (Institute of Electrical and Electronics Engineers Inc., 2017-01-01) Tasgetiren M.F.; Pan Q.-K.; Kizilay D.; Velez-Gallego M.C.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    This paper proposes a populated variable block insertion heuristic (PVBIH) algorithm for solving the permutation flowshop scheduling problem with the makespan criterion. The PVBIH algorithm starts with a minimum block size being equal to one. It removes a block from the current solution and inserts it into the partial solution randomly with a predetermined move size. A local search is applied to the solution found after several block moves. If the new solution generated after the local search is better than the current solution, it replaces the current solution. It retains the same block size as long as it improves. Otherwise, the block size is incremented by one and a simulated annealing-type of acceptance criterion is used to accept the new solution. This process is repeated until the block size reaches at the maximum block size. In addition, we present a randomized profile fitting heuristic with excellent results. Extensive computational results on the Taillard's well-known benchmark suite show that the proposed PVBIH algorithm substantially outperforms the differential evolution algorithm (NS-SGDE) recently proposed in the literature. © 2017 IEEE.
  • Publicación
    Benchmarking methodology on lean manufacturing in the apparel industry
    (Fraunhofer-Verlag, 2011-01-01) Juan Gregorio, A.P.; Victoria Eugenia, B.H.; María Jimena, R.M.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    This project provides the methodology to apply a Benchmarking approach between different companies in the apparel sector, the aim of the project is to evaluate the implementation degree of Lean manufacturing in their productive processes, specifically companies that produce blue jeans, T-shirts and polo shirts. This industry sector is very developed in the city of Medellin and it is one of the most dynamic industries, hence the interest in evaluation. For the Benchmarking methodology development, a questionnaire is needed to be constructed and applied in different companies in the city, the most important result was that, the implementation of Lean manufacturing techniques are not widespread among the industry and only those with big experience as exporters or international brands licensees are more advanced in their application and development.
  • Publicación
    A multi-objective evolutionary approach to improve the environmental performance of a supply chain
    (Institute of Industrial Engineers, 2017-01-01) Ozden S.G.; Vélez-Gallego M.C.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    The problem of improving the environmental performance of a supply chain without entailing excessive cost is becoming a frequent problem as companies face an increasing pressure from governments and customers for reducing the environmental impact of their activities. As the environmental improvement of an operating supply chain implies not only technology upgrading decisions, but also decisions regarding the structure of the supply chain itself
  • Publicación
    An approach for printing the maximum possible number of images
    (Institute of Industrial Engineers, 2017-01-01) Rojas-Santiago M.; Barbosa R.C.; Muthuswamy S.; Hulett M.; Velez-Gallego M.C.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    This paper considers a real life application of a printing process in a lithographic company that manufactures food packaging bags. The focus area of this problem is to print a variety of 2D images of bags on a surface area for maximum press layouts, with a constraint that the orientation of all bags is fixed and they should be placed parallel to the edges of the impression material. The problem under study is NP-hard and is an extension of the classical knapsack problem. An algorithm to maximize the number of rectangular images of bags that can be placed within the printing material is proposed. The results were compared with a Particle Swarm Optimization (PSO) metaheuristic. Several numerical experiments show that our procedure outperforms the PSO algorithm and improves the lithography's performance.
  • Publicación
    Use of a serious game for teaching operations programming: Students' perceptions
    (Institute of Electrical and Electronics Engineers Inc., 2018-01-01) Carmona Gonzalez G.L.; Pelaez Valencia L.E.; Trefftz H.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    This paper describes the experiences in the design, construction and validation of a serious game to be used as a support to teach Operations Management (or Operations Programming) in a Production Engineering program. The aim of this publication is to describe the perceptions of the students during the various development stages of the process. A semi-experimental study was conducted in order to determine the pedagogical effectiveness of the use of the game, but in this paper the authors focus on the perceptions of the students, which may become an important input for other faculty interested on using serious games as support for teaching other engineering courses. © 2018 IEEE.
  • Publicación
    Combining LR and 2-opt for scheduling a single machine subject to job ready times and sequence dependent setup times
    (Institute of Industrial Engineers, 2014-01-01) Rojas-Santiago, M.; Muthuswamy, S.; Vélez-Gallego, M.C.; Montoya-Torres, J.R.; Universidad EAFIT. Departamento de Ingeniería de Producción; Gestión de Producción y Logística
    In this research, the job ready times and sequence-dependent setup times of a single machine scheduling problem are considered with the objective of makespan minimization. As the problem is NP-hard, a Lagrangean Relaxation (LR) approach is proposed to find an initial solution and a heuristic based on 2-opt was implemented to improve it. Extensive computational experiments showed that the proposed combination of LR and 2-opt is effective. Wide range of test problems from 25 to 75 jobs was studied. The performance of the proposed approach was compared with the results from a commercial solver.
  • Ítem
    Emotional Networked maps from EEG signals
    (Institute of Electrical and Electronics Engineers Inc., 2020-01-01) Gomez A.; Quintero O.L.; Lopez-Celani N.; Villa L.F.; Gomez A.; Quintero O.L.; Lopez-Celani N.; Villa L.F.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    The EEG has showed that contains relevant information about recognition of emotional states. It is important to analyze the EEG signals to understand the emotional states not only from a time series approach but also determining the importance of the generating process of these signals, the location of electrodes and the relationship between the EEG signals. From the EEG signals of each emotional state, a functional connectivity measurement was used to construct adjacency matrices: lagged phase synchronization (LPS), averaging adjacency matrices we built a prototype network for each emotion. Based on these networks, we extracted a set node features seeking to understand their behavior and the relationship between them. We found through the strength and degree, the group of representative electrodes for each emotional state, finding differences from intensity of measurement and the spatial location of these electrodes. In addition, analyzing the cluster coefficient, degree, and strength, we find differences between the networks from the spatial patterns associated with the electrodes with the highest coefficient. This analysis can also gain evidence from the connectivity elements shared between emotional states, allowing to cluster emotions and concluding about the relationship of emotions from EEG perspective. © 2020 IEEE.
  • Ítem
    Estimation of fundamental diagrams in large-scale traffic networks with scarce sensor measurements
    (Institute of Electrical and Electronics Engineers Inc., 2018-01-01) Montoya O.L.Q.; Canudas-De-Wit C.; Montoya O.L.Q.; Canudas-De-Wit C.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    The macroscopic fundamental diagram (MFD) relates space-mean flow density and the speed of an entire network. We present a method for the estimation of a 'normalized' MFD with the goal to compute specific Fundamental Diagram in places where loop sensors data is no available. The methodology allows using some data from different points in the city and possibly combining several kinds of information. To this aim, we tackle at least three major concerns: the data dispersion, the sparsity of the data, and the role of the link (with data) within the network. To preserve the information we decided to treat it as two-dimensional signals (images), so we based our estimation algorithm on image analysis, preserving data veracity until the last steps (instead of first matching curves that induce a first approximation). Then we use image classification and filtering tools for merging of main features and scaling. Finally, just the Floating Car Data (FCD) is used to map back the general form to the specific road where sensors are missing. We obtained a representation of the street by means of its likelihood with other links within the same network. © 2018 IEEE.
  • Ítem
    Standardized Approaches for Assessing Metagenomic Contig Binning Performance from Barnes-Hut t-Stochastic Neighbor Embeddings
    (SPRINGER, 2020-01-01) Ceballos J.; Ariza-Jiménez L.; Pinel N.; Ceballos J.; Ariza-Jiménez L.; Pinel N.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    The performance of unsupervised methods for metagenomic binning is often assessed using simulated microbial communities. The lack of well-characterized evaluation protocols and approaches to community construction cognizant of biological realities impedes the rigorous assessment and standardization of the binning process. This work attempted to standardize performance evaluation using benchmark communities constructed according to the genome similarity metric Average Amino Acid identity. This approach allowed us to extend and deepen our previous research on the unsupervised binning of metagenomic sequence fragments based on low-dimensional embeddings of pentamer frequency profiles. Experimental results evidenced our method’s potential for the binning of metagenomic contigs to become an alternative to state-of-the-art methods such as MetaCluster 3.0. © 2020, Springer Nature Switzerland AG.
  • Ítem
    HIPAE helicopter-borne in-situ pollution assessment experiment: Plataforma alternativa para la medición de contaminantes en capas verticales
    (Institute of Electrical and Electronics Engineers Inc., 2019-01-01) Botero A.Y.; Florez J.; Duque J.F.; Rendon A.; Lopez-Restrepo S.; Pinel N.; Quintero O.L.; Oquinte1@eafit.edu.co; Rodriguez J.S.; Galvez J.; Lopera D.V.; Montilla E.; Marulanda J.I.; Isaza C.; Lainez M.L.A.; Zapata A.F.; Botero A.Y.; Florez J.; Duque J.F.; Rendon A.; Lopez-Restrepo S.; Pinel N.; Quintero O.L.; Oquinte1@eafit.edu.co; Rodriguez J.S.; Galvez J.; Lopera D.V.; Montilla E.; Marulanda J.I.; Isaza C.; Lainez M.L.A.; Zapata A.F.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
  • Ítem
    Mixed-Integer Linear Programming Models for One-Commodity Pickup and Delivery Traveling Salesman Problems
    (Springer Verlag, 2019-01-01) Palacio J.D.; Rivera J.C.; Palacio J.D.; Rivera J.C.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    This article addresses two different pickup and delivery routing problems. In the first one, called the one-commodity pickup and delivery traveling salesman problem, a known amount of a single product is supplied or demanded by a set of two different types of locations (pickup or delivery nodes). Therefore, a capacitated vehicle must visit each location once at a minimum cost. We also deal with the relaxed case where locations can be visited several times. In the last problem, the pickup or delivery operation can be split into several smaller pickups or deliveries, and also locations can be used as temporal storage points with the aim of reducing the cost of the route. To solve these problems, we present two mixed-integer linear programming models and we solve them via commercial solver. We analyze how several visits to a single location may improve solution quality and we also show that our simple strategy has a good performance for instances with up to 60 locations. © 2019, Springer Nature Switzerland AG.
  • Ítem
    Meteorological Risk Early Warning System for Air Operations
    (Institute of Electrical and Electronics Engineers Inc., 2019-01-01) Florez Zuluaga J.A.; David Ortega Pabon J.; Vargas Bonilla J.F.; Quintero Montova O.L.; Florez Zuluaga J.A.; David Ortega Pabon J.; Vargas Bonilla J.F.; Quintero Montova O.L.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    Today, airspace control has the challenge of merging information from independent and heterogeneous systems in order to minimize air safety risks and facilitate the decision-making process. One of the main risks for air operations is meteorology because convective formations like Torre cumulus or cumulonimbus could generate several dangerous phenomena such as icing, wind gusts, and thunderstorms, among others, that can affect the air operation safety. Based on previous works that allow the automatic identification of convective phenomena through the fusion of multispectral satellite images and other sources as winds and Meteorological Aerodrome Report (METAR), and establishing a common georeferenced coordinates system like WGS-84, for all sources, it can generate a system that could calculate early alerts about hazardous weather conditions in the aircrafts proximality for air traffic control system. For this, a meteorological analysis system can generate information about convective clouds calculating area, heights, temperatures, risk level and position of the meteorological formation. Parallelly the convective cloud is surrounded by optimal elliptical forms centered on the convective formation, generating a meteorological object. On the other hand, there is a system responsible for monitoring the information of the surveillance sensors. This system fused the air traffic sensors available like primary and secondary radar signals and ADS-B sensors in a unique WGS-84 coordinates system. Finally, in a georeferenced raster-Type graphing system or in a Geographic Information System (GIS), the meteorological and surveillance information is correlated projecting the track routes generates by air traffic system and traces generated by meteorological objects in order to establish times and high-risk areas, early. With this information, the Air Traffic Controller (ATC) system users, could minimize risk areas and reorganize the air traffic flow. This methodology then, would contribute to the decision-making process of ATC, facilitating the air flow reorganization and minimizing meteorological risks. For the development of this project a cooperative experimental methodology by subsystems was used. It was based on an operational knowledge and normal operating procedures of the Colombian Air Force, integrated with radar tracking technologies that implement decision trees. These alerts allow the air traffic controller to assess the risk and in accordance with the evaluation, if necessary, reorganize the air traffic flow for a specific area before the aircraft enter areas of bad weather mitigating the risks. © 2019 IEEE.
  • Ítem
    Attenuation of reverse time migration artifacts using Laguerre-Gauss filtering
    (European Association of Geoscientists and Engineers, EAGE, 2017-06-12) Paniagua, Juan Guillermo; Lucia Quintero M, O.; Paniagua, Juan Guillermo; Lucia Quintero M, O.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    Low-frequency artifacts appear in seismic images obtained by reverse time migration with the zero-lag crosscorrelation imaging condition due to the unwanted correlation of diving waves, head waves and backscattered waves. These artifacts can hide important details in the image and different methods have been proposed to attenuate or reduce them. The Laplacian filtering is the common post-processing technique to reduce the artifacts, but it increases the high-frequency noise in the image. Paniagua and Sierra-Sosa (2016) proposed the use of the Laguerre-Gauss spatial filtering (LGSF) to reduce the artifacts and enhance subsurface structures in the seismic image.\\ In this work, we describe the performance of the LGSF and demonstrate the good behavior of this postprocessing technique through synthetic examples. We used the original and different smoothed velocity models to show the capabilities of the LGSF and the results obtained in presence of small changes in the images. We demonstrate that despite the smoothed velocity models the LGSF preserves well the reflections with their true locations and significantly attenuates the low-frequency noise.
  • Ítem
    Short Research Advanced Project: Development of Strategies for Automatic Facial Feature Extraction and Emotion Recognition
    (IEEE, 2017-10-18) Restrepo, David; Gomez, Alejandro; Restrepo, David; Gomez, Alejandro; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    Emotions are a fundamental part of the personal and social skills of the human being. The behavior, intelligence, reason and decision making process are some of the topic that can be influenced by the emotional state of a person. In this paper we develop a computational way for emotion recognition though images using the Cohn-Kanade database to train a pattern recognition neural network and Viola Jones object detector to extract the information of the facial expression. The resulting neural network showed an overall accuracy of 90.7% in recognizing between 6 basic emotions such a surprise, fear, happiness, sadness, disgust and anger.
  • Ítem
    A Mixed-Integer Linear Programming Model for a Selective Vehicle Routing Problem
    (Springer Verlag, 2018-01-01) Posada A.; Rivera J.C.; Palacio J.D.; Posada A.; Rivera J.C.; Palacio J.D.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    In this paper, we propose a new vehicle routing problem variant. The new problem is a type of selective vehicle routing model in which it is not necessary to visit all nodes, but to visit enough nodes in such a way that all clusters are visited and from which it is possible to cover all nodes. Here, a mixed-integer linear programming formulation (MILP) is proposed in order to model the problem. The MILP is tested by using adapted instances from the generalized vehicle routing problem (GVRP). The model is also tested on small size GVRP instances as a special case of our proposed model. The results allow to evaluate the impact of clusters configuration in solver efficacy. © 2018, Springer Nature Switzerland AG.
  • Ítem
    Emotion Recognition from EEG and Facial Expressions: A Multimodal Approach
    (Institute of Electrical and Electronics Engineers Inc., 2018-01-01) Chaparro V.; Gomez A.; Salgado A.; Quintero O.L.; Lopez N.; Villa L.F.; Chaparro V.; Gomez A.; Salgado A.; Quintero O.L.; Lopez N.; Villa L.F.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    The understanding of a psychological phenomena such as emotion is of paramount importance for psychologists, since it allows to recognize a pathology and to prescribe a due treatment for a patient. While approaching this problem, mathematicians and computational science engineers have proposed different unimodal techniques for emotion recognition from voice, electroencephalography, facial expression, and physiological data. It is also well known that identifying emotions is a multimodal process. The main goal in this work is to train a computer to do so. In this paper we will present our first approach to a multimodal emotion recognition via data fusion of Electroencephalography and facial expressions. The selected strategy was a feature-level fusion of both Electroencephalography and facial microexpressions, and the classification schemes used were a neural network model and a random forest classifier. Experimental set up was out with the balanced multimodal database MAHNOB-HCI. Results are promising compared to results from other authors with a 97% of accuracy. The feature-level fusion approach used in this work improves our unimodal techniques up to 12% per emotion. Therefore, we may conclude that our simple but effective approach improves the overall results of accuracy. © 2018 IEEE.
  • Ítem
    Efficient use of mobile devices for quantification of pressure injury images
    (IOS Press, 2018-01-01) Garcia-Zapirain B; Sierra-Sosa D; Ortiz P D; Isaza-Monsalve M; Elmaghraby A; Garcia-Zapirain B; Sierra-Sosa D; Ortiz P D; Isaza-Monsalve M; Elmaghraby A; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    Pressure Injuries are chronic wounds that are formed due to the constriction of the soft tissues against bone prominences. In order to assess these injuries, the medical personnel carry out the evaluation and diagnosis using visual methods and manual measurements, which can be inaccurate and may generate discomfort in the patients. By using segmentation techniques, the Pressure Injuries can be extracted from an image and accurately parameterized, leading to a correct diagnosis. In general, these techniques are based on the solution of differential equations and the involved numerical methods are demanding in terms of computational resources. In previous work, we proposed a technique developed using toroidal parametric equations for image decomposition and segmentation without solving differential equations. In this paper, we present the development of a mobile application useful for the non-contact assessment of Pressure Injuries based on the toroidal decomposition from images. The usage of this technique allows us to achieve an accurate segmentation almost 8 times faster than Active Contours without Edges (ACWE) and Dynamic Contours methods.We describe the techniques and the implementation for Android devices using Python and Kivy. This application allows for the segmentation and parameterization of injuries, obtain relevant information for the diagnosis and tracking the evolution of patient's injuries. © 2018 - IOS Press and the authors.