Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Objective: The objective was to determine competent tourist guides to carry out tours in cases of immediacy presented in agencies of Cartagena de Indias. Methodology: The research was of a mixed type with a sequential exploratory exploration design, where the interview technique was applied to obtain direct information from employees who work in tourism companies located in Cartagena de Indias and the bibliographic review technique in order to obtain literary references that provide relevant information on the topic addressed in this research. The foregoing served as a basis to correctly apply the Ideas Assessment Matrix technique and determine competent tourist guides to carry out tours in cases of immediacy presented at agencies of Cartagena de Indias. Results: The appropriate tour guide was obtained to carry out the tour in case of immediacy, which has different advantages such as the knowledge of different languages and the adequate handling of the guide techniques. Conclusions: The application of the Ideas Assessment Matrix technique allowed determining competent tourist guides to carry out tours in cases of immediacy presented at agencies of Cartagena de Indias.

Context: Studies carried out in low voltage networks have explored the modeling of linear single-phase loads (such as motors) and non-linear ones (such as those based on power electronics). However, induction motors exhibit non-linear characteristics between voltage and current due to the saturation of their magnetic parts. Therefore, it is necessary to study induction motors in the frequency domain with a model that allows reviewing the characteristic nonlinearity of their voltage-current interaction. Methodology: This article presents the frequency domain modeling of a single-phase induction motor used as a silent air extractor (127 V, 60 Hz, 66 W), which presents a capacitive behavior (fp = 0,93 in leading) and harmonic distortion due to a third-order component (7,0%) when fed with a pure sinusoidal voltage of 127 V. Results: This work establishes the parameters of two approaches to the Norton equivalent model (coupled and decoupled admittance matrix) which are used to estimate the distorted current signal and the values ​​of consumed active and non-active power. The results show comparisons errors of P, Q, THDi, and NRMSE indices of less than 7, 4, 14, and 3%, respectively. Conclusions: The parameters of the Norton equivalent model estimated for the single-phase induction motor allow calculating the current signal with a high degree of precision. This signal exhibits nonlinear characteristics and a capacitive behavior due to the permanent presence of a capacitor aiding the start and operation of the engine.

Abstract Objective: This work involves a convex-based mathematical reformulation for the optimal power flow problem in DC networks. The objective of the proposed optimization model corresponds to the minimization of the power losses through all the network branches considering a convex conic model that warranties finding the global optimal. Methodology: This is split into three stages: The first stage presents the mathematical model of optimal power flow for DC networks and all its geometric features that make it non-convex; the second stage presents the convex reformulation from a second order conic relaxation; the third stage shows the main characteristics of the DC system under study; and the fourth stage presents the optimal solution of the power flow problem and its comparisons with some methods reported in the specialized literature.     Results: The numerical validations demonstrate that the model of proposed convex optimal power flow obtains the same solution as the exact model of the problem with an efficiency of 100%, which is in contrast with the variability of the results that are presented by the metaheuristic techniques reported as comparison methodologies.     Conclusions: The proposed second-order conic relaxation warrantied the convexity of the solution space and therefore, the finding of the optimal solution at each execution; besides of this, demonstrated that for optimal power flow problems in DC networks, the numerical performance is better than most of the comparative metaheuristic methods; and the provided solution by the proposed relaxation is equivalent to that provided by the exact model. Keywords: Direct current networks, second-order conic relaxation, non-linear programming model, convex optimization.

Context: This article presents the design of a computational predictive model that facilitates the recognition of Colombian Sign Language (LSC) in a hotel and tourism environment. Method: Artificial intelligence techniques and deep neural networks were applied in the learning and prediction of gestures in real time, which allowed the construction of a tool to reduce the gap and strengthen communication. Convolutional neural network algorithms were applied to real-time data capture. Movement was captured using mobile device video cameras, thus obtaining the images that make up the data set. The images were used as training data for an optimal computational model that can predict the meaning of a newly presented image. Results: The performance of the model was evaluated using categorical measures and comparing different configurations for the neural network. In addition to this, everything is supported with the use of tools such as Tensorflow, OpenCV and MediaPipe. Conclusions: Finally, a model capable of identifying and translating 39 different signs between words, numbers and basic phrases focused on the hotel sector was obtained, where a success rate of 97.6% was obtained in a controlled use environment.  

Objective: Reviewing and contrasting quantitative public space (PS) quality assessment methods that can contribute to the fulfillment of the sustainable development goals (SDG). Methodology: Authors selected seven evaluation methods from research available in the SCOPUS, SpringerLink, ScienceDirect, Latindex, Scielo, and Redalyc databases based on publications between 2000 and 2020. According to the citations found in said documents, the authors included significant references from previous years. The authors contrasted the methods according to quality dimensions, weighting criteria, and variables. Results: The public space quality evaluation with quantitative methods contributes to the fulfillment of the sustainable development goals because it uses concrete and measurable goals. Quantitative data eases the technical diagnosis of public space elements conditions. The authors grouped the variables into dimensions; accessibility and comfort have the most significant relationship with the sustainable development goals. The reviewed methods are expensive and complex; they need an analysis of users’ activities and behaviors. It is challenging to make infrastructure needs visible and meet sustainable development goals for good-quality public space without practical methods. Conclusions: The reviewed methods include a quality evaluation, without disaggregation, of individual elements that constitute the public space. It is a challenge to design evaluation instruments for all types of public spaces. The traditional practice is to build new spaces or remodel existing ones without considering the financing for the maintenance of the entire system. Financing: Universidad Nacional de Colombia.

Objective: To design and build an instrument capable of measuring long-wave infrared radiation with elements of the national market that offers an excellent performance in measuring energy in this spectral band. Methodology: The best design was determined based on other existing instruments, innovating its development by using materials that are easily accessible in the country, and its operation was verified by characterizing an incandescent light bulb used as an infrared radiation pattern. Then, the radiation measured by the instrument was compared to that emitted by the source by means of an experimental setup that involved measuring the temperature at several distances. Results: A functional prototype was obtained, and its operation could be verified through a series of irradiance measurements according to the Stefan-Boltzmann law, through a calibration process with a known radiation source. Conclusions: A radiometric instrument for the thermal infrared band was designed and built. Raw materials and electronic components were used which were available in the local market, thus noticeably reducing the equipment’s production costs. Funding: This research was funded by the authors.

Context: Given the increasing population concentration, both the proximity of the town of Madrid to the city of Bogotá and the growing metropolitan area around the latter have a significant influence on the increased urbanization and the change in land use in the town of Madrid, Cundinamarca. Objective: The objective of this study was to carry out a multitemporal analysis of the change in coverage and land use caused by urban expansion in the municipality of Madrid between 1977 and 2020.  Methodology: Satellite images were observed through supervised classification, following the Corine Land Cover methodology, which was adapted for the Colombian context, and utilizing geographic information systems. Area variation analyses were performed for each classification in each of the evaluated years. Results: The data obtained show that the forest cover area and seminatural zones have been reduced by 86% in a period of 43 years, and that artificial territories have progressively become predominant in each of the years, even reaching a coverage greater than 50% of the municipality area. The agricultural territories have maintained 66,95% of the surface of the municipality, and they correspond the land use with the largest occupied area for the evaluated period, which shows the importance of the soil for the economic development of the population. Conclusions: This situation shows that population growth and urban expansion cause variations in coverage and land uses. Their valuation is an aspect that must be considered when elaborating development plans for municipal entities.

Context: The location of logistics operators can become a competitive advantage for organizations as it guarantees their effective response to changes in society. Method: This paper presents the formulation of the linear programming model for the location of a logistics operator in each of the periods of a planning horizon. Results: Compliance with the location of the logistics operator with its respective restrictions at a minimum cost is guaranteed; in addition, to preserve the clear functions of dynamic programming throughout the planning horizon. Conclusions: Linear programming is an operations research technique widely used in all business fields; for which in this application it is used to guarantee the location of the logistics operator from one period to another with the sole causation of the necessary costs that guarantee a minimum total for it. This can be visualized based on the specific data used.

Introducción: el abuso sexual en la infancia se define como una experiencia traumática que puede llevar a la víctima a padecer complicaciones mentales, sexuales, físicas, interpersonales y comportamentales, nefastas para la salud. Además, constituye un factor de riesgo que desencadena el trastorno depresivo mayor en mujeres.Presentación del caso: se trata de una paciente femenina de 17 años de edad que sufrió abuso sexual a los siete años de edad. La paciente ingresa en una primera ocasión el 5 marzo de 2018 por intento suicida y trastorno depresivo al tener contacto con la persona que efectuó el acto. Pasados 17 días la paciente vuelve a ser ingresada por presentar un cuadro de trastorno depresivo mayor y egresa nueve días después por buena evolución. El 7 de agosto ingresa por tercera vez por trastorno depresivo mayor e intento suicida nuevamente. La paciente fue tratada con Imipramina de 25 mg dos veces al día y con tratamiento psicoterapéutico, al cual respondió adecuadamente. La paciente se encuentra psicológicamente estable.Conclusiones: el abuso sexual en la niñez constituye un factor de riesgo desencadenante del trastorno depresivo mayor. La atención especial mediante apoyo y estudios psicológicos de los pacientes, y el tratamiento de fármacos antidepresivos es de vital importancia para la recuperación de víctimas sometidas a acoso sexual con ideación e intento suicidas. 

Introducción: la condición del sistema estomatognático tiene un impacto directo en la salud general, el rendimiento deportivo y el riesgo de padecer lesiones en los adolescentes que practican deportes.Objetivo: comprobar el nivel de información sobre salud bucodental y práctica deportiva en los adolescentes de los deportes de combate y juego con pelotas de la EIDE Provincial Lino Salabarría Pupo de Sancti Spíritus en 2020.Métodos: se realizó un estudio descriptivo de corte transversal, durante el mes de diciembre de 2020. La población estuvo conformada por 307 adolescentes de los deportes de combate y juego con pelotas de la Escuela de Iniciación Deportiva Escolar Provincial Lino Salabarría Pupo de Sancti Spíritus. Se seleccionó una muestra probabilística y aleatoria de 53 adolescentes. Se utilizó la encuesta para constatar el criterio de los adolescentes en relación con el conocimiento general sobre salud bucodental y práctica deportiva.  Resultados: predominó  el   género masculino con un 62,3 % del total de  encuestados.  El 64,2 % de los adolescentes manifestaron que nunca usan el protector  bucal. El 67,9 % y el 52,8 % nunca habían recibido charlas educativas sobre traumatismos dentales e higiene bucal respectivamente. Conclusiones: el nivel de información sobre salud bucodental y práctica deportiva en los adolescentes de los deportes de combate y juego con pelotas es inadecuado. En la actualidad es imprescindible educar a los deportistas desde una edad tan temprana como la adolescencia sobre los problemas potenciales de las afecciones bucales y las medidas preventivas.