Examinando por Autor "Gatica, G."
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Ítem A bibliometric review of the use of 3D printing in maritime and port education: trends and perspectives(Elsevier, 2024) Mojica, J.; Piñeres, A.; Huyke, A.; Gatica, G.; Olmedo, A.Three-dimensional (3D) printing, a technology in constant evolution, stands as a resource of great significance in the transformation of maritime and port education. In this article, we conduct a comprehensive bibliometric review with the purpose of identifying emerging trends and perspectives in this field. In the methods section, we develop on the search equation and the rigorous selection and eligibility criteria that guided our research. The results, presented in the corresponding section, reveal a steady growth in the use of 3D printing in maritime and port education in recent years, as well as a diversity of applications that enrich the teaching of concepts and skills related to these disciplines. Furthermore, we highlight the most relevant thematic areas and analyze the key trends and challenges that will require attention in the future. In conclusion, this study underscores the significant potential of 3D printing to enhance both learning and teaching in the realm of maritime and port education and provides crucial recommendations for future research in this promising field.Ítem A CHASIDE Test-based Analysis for Identifying Adolescents Characteristics Impacting their Vocational Orientation: Case of private schools in the city Barranquilla, Colombia(Elsevier, 2024) Acosta, C.; Acuña-Rodríguez, M.; Peñaranda-Osorio, E.; Gatica, G.; Córdova, A.This research is oriented to the identification of characteristics in the choice of professional careers in adolescents in eleventh grade. A total of 270 young people between the ages of 15 and 20 years old, all students at private schools in the city of Barranquilla, Colombia, were surveyed. A test called CHASIDE was used, which is focused on the occupational environment. Among the results, we found career options chosen by the students, the different inclinations in the workplaces where they plan to work, competencies in adolescents regarding the choice of career, and the identification of learning channels according to areas of knowledge. In the future, we seek to analyze whether there is a relationship between learning channels, personality, and career choice, and thus develop technological tools and algorithms for career choice, in order to address career orientation as the main axis of success in higher education.Ítem A comparison of trajectory granular based algorithms for the location-routing problem with heterogeneous fleet (LRPH)(Universidad Nacional de Colombia, 2017) Bernal-Moyano, J.A.; Escobar, J.W.; Marín-Moreno, C.; Linfati, R.; Gatica, G.We consider the Location-Routing Problem with Heterogeneous Fleet (LRPH) in which the goal is to determine the depots to be opened, the customers to be assigned to each open depot, and the corresponding routes fulfilling the demand of the customers and by considering a heterogeneous fleet. We propose a comparison of granular approaches of Simulated Annealing (GSA), of Variable Neighborhood Search (GVNS) and of a probabilistic Tabu Search (pGTS) for the LRPH. Thus, the proposed approaches consider a subset of the search space in which non-favorable movements are discarded regarding a granularity factor. The proposed algorithms are experimentally compared for the solution of the LRPH, by taking into account the CPU time and the quality of the solutions obtained on the instances adapted from the literature. The computational results show that algorithm GSA is able to obtain high quality solutions within short CPU times, improving the results obtained by the other proposed approaches.Ítem A faster optimal model slotting in rack positions with mono SKU pallet(Elsevier, 2022) Rios, J.; Morillo-Torres, D.; Olmedo, A.; Coronado-Hernandez, J.; Gatica, G.The warehouse, with its racking positions, oversees regulate the flow of goods in the distribution center (DC). An adequate distribution of the products in the warehouse (slotting), reduces the operating picking times once is done by a full pallet. This paper presents a mathematical model that optimizes slotting times in a selective shelving and random storage warehouse. The model places the products with the highest turnover rate and ABC inventory valuation close to the dispatch area. In addition, it places high-value products on the upper shelf levels and heavy pallets on the lower levels. The results applied to a company dedicated to the manufacture of cellulose pulp and derivatives, obtained a 19.24% reduction in operating time.Ítem A flexible mathematical model for the planning and designing of a sporting fixture by considering the assignment of referees(Growing Science, 2019-04) Linfati, R.; Gatica, G.; Escobar, J.W.This paper deals with the problems faced with the designing and planning of a sporting fixture considering correct referee assignments. A non-linear binary program model is proposed to solve the problems, which aims to minimize the sums of the differences that exist between the requirements of each match and the quality of the referee assigned achieving the design of the most adequate referee for each match. The efficiency of the proposed model is proved using some real data obtained from various fixtures for sports such as soccer, volleyball, and basketball. The mathematical model is solved by using CPLEX 12.7.0., which allows the automatic linearization of the problems. The results obtained demonstrate the efficiency of the proposed methodology for tackling problems, as well as its extension to other sporting disciplines, which require a similar type of planning. Similarly, given the robust nature of the proposed model, it is possible to implement other objective functions in accordance with the requirements of each league. © 2019 by the authors; licensee Growing Science, Canada.Ítem A practical methodology of design of off-line reservoirs for reducing maximum water levels in urban channels(Elsevier B.V., 2020-08) Coronado-Hernandez, O.; Coronado-Hernandez, J.; Gatica, G.Flooding can often occur in many places due to the increasing trend of rainfall events (climate change), the urbanization process of a catchment area, or by an undersized urban channel. Reservoirs are used for limiting flooding since they can store an enough water volume. This research presents a practical procedure for sizing off-line reservoirs with an application in urban channels for places with space limitations. A complete formulation is presented, which can be easily used for designers and engineers for computing dimensions of off-line reservoirs. The formulation is applied to a case study located at the Cartagena de Indias, Colombia.Ítem Accident Risk Detection in Urban Trees using Machine Learning and Fuzzy Logic(Elsevier, 2022) Ramírez, G.; Salazar, K.; Barria, V.; Pinto, O.; San Martin, L.; Carrasco, R.; Fuentealba, D.; Gatica, G.Knowing the state of trees and their associated risks contribute to the care of the population. Machine Learning, through supervised learning, has demonstrated its effectiveness in various areas of knowledge. The risk of accidents can be predicted by having different tree data, including height, species, condition, presence of pests, the area where it is planted, climatic events, and age. This work proposes a platform to register trees and predict their risk. The solution considers integrating technology and applications for those in charge of maintenance and changes in current procedures. The risk prediction process is carried out through a fuzzification process that contributes to the responsible entities’ decision-making. Preliminary results of this research are presented, and the capacity of the developed software architecture is demonstrated, where the scalability of the prediction algorithm stands out.Ítem Automatically Generated Algorithms for the Vertex Coloring Problem(Public Library of Science, 2013) Contreras, C.; Gatica, G.; Parada, V.The vertex coloring problem is a classical problem in combinatorial optimization that consists of assigning a color to each vertex of a graph such that no adjacent vertices share the same color, minimizing the number of colors used. Despite the various practical applications that exist for this problem, its NP-hardness still represents a computational challenge. Some of the best computational results obtained for this problem are consequences of hybridizing the various known heuristics. Automatically revising the space constituted by combining these techniques to find the most adequate combination has received less attention. In this paper, we propose exploring the heuristics space for the vertex coloring problem using evolutionary algorithms. We automatically generate three new algorithms by combining elementary heuristics. To evaluate the new algorithms, a computational experiment was performed that allowed comparing them numerically with existing heuristics. The obtained algorithms present an average 29.97% relative error, while four other heuristics selected from the literature present a 59.73% error, considering 29 of the more difficult instances in the DIMACS benchmark.Ítem Balanced Medical Image Classification with Transfer Learning and Convolutional Neural Networks(MDPI, 2022-02) Benavente, D.; Gatica, G.; González-Feliu, J.This paper aims to propose a tool for image classification in medical diagnosis decision support, in a context where computational power is limited and then specific, high-speed computing infrastructures cannot be used (mainly for economic and energy consuming reasons). The proposed method combines a deep neural networks algorithm with medical imaging procedures and is implemented to allow an efficient use on affordable hardware. The convolutional neural network (CNN) procedure used VGG16 as its base architecture, using the transfer learning technique with the parameters obtained in the ImageNet competition. Two convolutional blocks and one dense block were added to this architecture. The tool was developed and calibrated on the basis of five common lung diseases using 5430 images from two public datasets and the transfer learning technique. The holdout ratios of 90% and 10% for training and testing, respectively, were obtained, and the regularization tools were dropout, early stopping, and Lasso regularization (L2). An accuracy (ACC) of 56% and an area under the receiver-operating characteristic curve (ROC—AUC) of 50% were reached in testing, which are suitable for decision support in a resource-constrained environment.Ítem Bibliometric analysis of energy management and efficiency in the maritime industry and port terminals: Trends(Elsevier, 2024) Mojica, J.; Piñeres, A.; Cabello, J.; Salais, T.; Cantillo, J.; Gatica, G.Energy management and efficiency in port terminals play a crucial role in addressing the environmental challenges of the maritime industry. This article presents a bibliometric review of the existing literature on the subject, focusing on trends in the field of energy management in port terminals. Through a systematic analysis of relevant academic articles, this study identifies key themes and emerging areas of interest. The findings highlight the growing attention to sustainable practices and energy optimization strategies in the maritime and port industry. The review reveals a growing body of research examining energy efficiency measures, renewable energy integration, and the application of advanced technologies. In addition, the analysis highlights the importance of stakeholder collaboration, policy frameworks and regulatory initiatives to promote sustainable energy management practices in port environments. This bibliometric review provides valuable information for researchers, practitioners and policy makers involved in the field of energy management in the maritime industry and port terminals. It provides a comprehensive overview of the current state of knowledge, identifies emerging trends, and points to possible areas for future research. The results of this study contribute to a better understanding of the current state of knowledge, identify emerging trends and point to possible areas for future research. The results of this study contribute to a better understanding of the challenges and opportunities associated with sustainable energy management in port terminals, facilitating the development of effective strategies to mitigate environmental impacts and optimize energy use in this critical sector.Ítem Conceptual Model for Retail Distribution in Nanostores: The case of the Southwest of Barranquilla, Colombia(Elsevier, 2024) López-Gómez, L.; Marriaga-Chamorro, S.; Pirabán-Ramírez, A.; Manosalva-Sandoval, J.; Gonzalez-Holgado, A.; Gatica, G.This article designs a conceptual model for the procurement and distribution processes in nanostores in the southwest of Barran-quilla, Colombia considering 256 nanostores. The data collection involved identifying the nanostores through a visit to the area and creating a data collection instrument with specific questions covering various variables. As a result of the model, the procurement process comprises stages such as ordering, order processing, preparation and dispatch, distribution, payment, return, and after-sales. The findings show that nanostores primarily use indirect distribution channels, establishing relationships with suppliers and placing orders directly or through sales agents. Based on the research findings, the article suggests implementing digital marketing platforms to facilitate order placement and delivery for nanostore owners, reducing their transportation costs and improving the condition of products received. This study contributes to understanding procurement and distribution dynamics in nanostores, providing valuable insights for nanostore owners, policymakers, and researchers, improving the operations and competitiveness of nanostores, benefiting both the local economy and the broader retail sector.Ítem Design and feasibility study for the evaluation of an Agrovoltaics generation system: Case of Temuco in Chile(Elsevier, 2024) Latorre, P.; Amigo, L.; Gatica, G.; Aguila, G.; Vidal-Pacheco, L.; Coronado-Hernández, J.Chile is a country that has had large renewable energy resources in recent years, and it has demonstrated a commitment to the use of clean energy. However, most solar energy projects are located in northern Chile, neglecting other areas, such as the southern part of the country, where the photovoltaic energy industry has the potential to thrive. This is the case in the Araucanía region, particularly in Temuco, which has diverse agricultural activity. However, being a remote area without access to the electrical grid, it relies on generation sources like oil. This article, a research product, aims to demonstrate the functionality that can be added to agricultural land by combining it with solar parks. To achieve this, an agrovoltaic system was estimated for a plot of land in the agricultural zone of Temuco. This system will serve as a sample of the integration between photovoltaic infrastructure and the agricultural industry for those interested in installing it.Ítem Efficient heuristic algorithms for location of charging stations in electric vehicle routing problems(National Institute for R and D in Informatics, 2018) Gatica, G.; Ahumada, G.; Escobar, J.W.; Linfati, R.Eco-responsible transportation contributes at making a difference for companies devoted to product delivery operations. Two specific problems related to operations are the location of charging stations and the routing of electric vehicles. The first one involves locating new facilities on potential sites to minimise an objective function related to fixed and operational opening costs. The other one, electric vehicle routing problem, involves the consolidation of an electric-type fleet in order to meet a particular demand and some guidelines to optimise costs. It is determined by the distance travelled, considering the limited autonomy of the fleet, and can be restored by recharging its battery. The literature provides several solutions for locating and routing problems and contemplates restrictions that are closer to reality. However, there is an evident lack of techniques that addresses both issues simultaneously. The present article offers four solution strategies for the location of charging stations and a heuristic solution for fleet routing. The best results were obtained by applying the location strategy at the site of the client (relaxation of the VRP) to address the routing problem, but it must be considered that there are no displacements towards the recharges. Of all the other three proposals, K-means showed the best performance when locating the charging stations at the centroid of the cluster. © 2012-2018. National Institute for R and D in Informatics.Ítem Exploring Blockchain Applications in the Transition to a Circular Economy: A Comprehensive Sector-Focused Review(Elsevier, 2024) Bravo-Núñez, M.; Molina-Dahjer, N.; Cerro-Barrios, M.; Lombana-Jiménez, A.; Gatica, G.; Romero-Conrado, A.Industry 4.0 technologies have become one of the main enablers for implementing Circular Economy e↵orts, creating smart and connected products, processes, and systems that can optimize resource usage, reduce waste, and improve efficiency, with a significant environmental impact. Blockchain is a technology that was initially centered on authentication and security applications. Currently, its utility has extended to solving multiple problems across industries. This paper explores the di↵erent applications of the Blockchain related to the circular economy. A systematic literature review method was applied to analyze the main objectives, advantages, disadvantages, opportunities, and challenges of implementing Blockchain in various industrial sectors. Results show a growing trend in applications with favorable impacts, especially in sectors like Manufacturing, Energy, and Automotive.Ítem Georeferenced Environmental Platform for Kindergarten Monitoring Based on Internet of Things and Websockets(Elsevier, 2024) Fuentes, J.; Silva, M.; Muñoz, C.; Reyes, H.; Bustamante-Encina, R.; Gatica, G.This project involves creating a real-time geo-referenced measurement platform for kindergartens, utilizing IoT technology and the WebSockets protocol to enhance environmental information in socially significant areas. The platform displays air quality data on a map and provides Twitter alerts for local pollution events. Tests in two kindergartens demonstrated effective data capture and transmission to a central server, achieving a 92% success rate at distances exceeding 800 meters. The platform also distinguished environmental differences between the kindergartens based on location, proving its utility in supporting parents and guardians in selecting kindergartens for their children.Ítem Hydrological Considerations for Sizing of a Barge Discharge Pipeline Runway(Elsevier, 2022) Coronado-Hernández, O.; Coronado-Hernández, J.; Romero-Conrado, A.; Gatica, G.; Olmedo, A.A key element for water supply systems is the design of the water intake components. Mobile floating platforms (barges) are helpful when the hydraulic system displays substantial variations in water levels. This study presents the hydrological considerations that should be considered for the design of the barge’s pipeline runway. The analysis takes into consideration the maximum and minimum water levels measured at the location. The study was carried out at the Magdalena River -Plato (Colombia) station, finding variations in water levels of between 12.3 m and 16.1 m for return periods of 25 and 100 years, respectively. This information is helpful for designers and consultants in order to design an appropriate barge pipeline runway.Ítem L-PECS: Application for Inclusive Work Environments(Elsevier, 2021) Lagos, P.; Baeza, R.; Pinto, O.; Costa, G.; Ruete, D.; Fuentealba, D.; Gatica, G.Children with ASD may show permanent communication problems due to a decline in the effectiveness of persistence of the information transacted. L-PECS is an application for Android smartphones that uses an alternative language called PECS, based on image exchange. L-PECS allows to improve the persistence of information in work contexts, generating effective communicational instances, task follow-up, and supporting the labor insertion of people with ASD. This work performed user interface tests, user action tests, usability, and accessibility tests on 20 users operating L-PECS to define and show possible behaviors. L-PECS can encourage the hiring of people with ASD.Ítem Maintenance Process Analysis in a Port Cargo Company through Discrete Event Simulation(Elsevier, 2024) Corrotea, H.; Portales, H.; Amigo, L.; Gatica, G.; Troncoso-Palacio, A.; Mondragón, D.; Ramos, M.Cargo transfer is a key procedure in port businesses; nevertheless, the electromechanical equipment employed for maintenance should adhere to a set of standards to ensure its proper operation all the time, which may raise production costs. Because of this, every improvement that enables minimizing production losses and expenses over the short, medium, and long time is a decisive choice that companies should consider becoming sustainable. Under this policy, the maintenance process has assumed a significant role as an integral part of the manufacturing process and not only as a dependency of the company. In this study, proposals for improving a port company's maintenance procedure will be analyzed using the discrete event simulation technique. The findings at the task execution stage reveal delays or queues that have a direct impact on the overall time necessary to accomplish maintenance. The reason that the equipment in the locations is not available on time could be due to a lack of supplies or replacement parts required to finish the repair. This has a negative impact on the scheduled maintenance times. Additionally, the simulation results show that incorporating one person into the process improves reaction times. However, the final recommendation is that a future role or workload study should be carried out instead of hiring other employees and, if possible, redistributing workloads among the people who are part of the company.Ítem Modeling hospital logistics capacity through system dynamics during the COVID-19 pandemic: case of Pasco Healthcare Network in Peru(Elsevier, 2024) Lock, R.; Benavente, Y.; Gatica, G.; Olivares, P.; Ramirez, J.; Gonzalez-Holgado, A.The present investigation, whose main objective is based on modeling the hospital logistics capacity in the Pasco Healthcare Network (Peru) through Systems Dynamics during the first and second wave of the appearance of the SARS-COVid-2 virus, oriented towards a study in the capacity to respond to the most intense health emergency in recent decades. In the first instance, the reality of the studied system was made known, which was possible thanks to the information provided by the actors that make up the hospital logistics capacity, sources uploaded to the WHO worldwide. Afterwards, we proceeded to characterize the variables that make up the system, prioritizing each of these through the application of a structural analysis that measured the levels of influence between one variable and another. Because of this, we proceeded to create the causal diagram, and likewise facilitate the inclusion of the network model through the Stella software. Once the model has been simulated, the results obtained are reported.Ítem Multimodal Capacitated Hub Location Problems with Multi-Commodities: An Application in Freight Transport(Hindawi Limited, 2020) Osorio-Mora, A.; Núñez-Cerda, F.; Gatica, G.; Linfati, R.Hub location problems (HLPs) support decision making on multimodal transport strategic planning. It is related to the location of hubs and the allocation of origin/destination (O/D) flow in a system. Classical formulations assume that these flows are predefined paths and direct delivery is not available. This applied research presents a mixed integer linear programming (MILP) model for a capacitated multimodal, multi-commodity HLP. Furthermore, an application on the export process in a Latin American country is detailed. The new proposed model, unlike the traditional HLP, allows direct shipment, and its O/D flows are part of the decision model. Situations with up to 100 nodes, six products, and two transport modes are used, working with initial and projected flows. All instances can be solved optimally using the commercial solver, Gurobi 7.5.0, in computational times less than a minute. Results indicate that only one hub is profitable for the case study, both for the initial and projected scenarios. The installation of a hub generates transport savings over 1% per year. Two factors affect the location decision: low concentration and distance between the hubs and destinations. Long distances involve an exhaustive use of trains instead of trucks, which leads to lower transport cost per unit.