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

Objective: To stablish a Dynamic modelo of the system wáter precipitation intensity – soil porosity and infiltration rate in order to measure the Depth of wáter infiltration and soil moisture that produce the landslide. Methodology: By applying System Dynamics, a causal diagram of the geotechnical variables of two simples from sites affected by mass remotion phenomenon in Pamplona (Colombia) was developed; the model was implementen with Stella v9 software. Results: The simulation results show the variation of soil Depth to be saturated to reach the liquid limit or the failure due to shear strength. Conclusions: The relation between mass removal and precipitation does not coincide with the current collective imaginary but by a characteristic type of precipitation for each soil type. Financing: This research was financed with the authors own resources.

Objective: This paper presents a review of the results obtained by an optimization methodology based on the application of the firefly algorithm (FA) as a metaheuristic planning tool with the purpose of finding the optimal facility layout in order to reduce the distances and flow times between processes of the production chain. Methodology: By means of implementing the MATLAB script, the goal was to evaluate the FA as applied to the facility layout distribution optimization problem, conducting a test of two facility layout cases with the algorithm. The FA was applied in order to evaluate the performance with respect to the initial facility layout configuration, as well as in comparison with a conventional heuristic algorithm. Results: The most relevant result was the verification of the FA’s degree of efficiency regarding the convergence time, as expressed in terms of the number of cycles required to reach an optimal solution in comparison with the conventional heuristic algorithm used for validation. Conclusions: The total optimized distance in the plant achieves a low significant value. A reduced number of iterations is required to reach an optimal value in the case of a complex facility layout.

Context: In the last decades, one has the impression that the term sustainable development has evolved towards social responsibility and that the activities carried out by organizations and institutions are very similar. Nevertheless, this paper presents a theoretical discussion of the contribution of social responsibility. The question of this research is: through indicators of general interest and scientific production, it is possible to determine the evolution of sustainable development towards social responsibility? Methodology: Using the non-participatory method of secondary data analysis, secondary data from articles in the Redalyc, WorldCat, Microsoft Academic, Scopus, and Web of Science databases and specialized books on the topics were analyzed. Google Ngram Viewer and Google Trends were used to compare the variations of the indicators of scientific production and interest. Results: Through secondary data analysis, it was possible to establish indicators of general interest and scientific production. A discussion is presented on the evolution of sustainable development towards social responsibility. Conclusions: The results showed that the evolution of sustainable development towards social responsibility was not surpassed over time, except at some moments and in specific geographical locations. Method: Using the non-participatory method of secondary data analysis, secondary data from articles in the Redalyc, WorldCat, Microsoft Academic, Scopus, Web of Science databases and specialized books on the topics were analyzed. The Google Ngram Viewer and Google Trends software were used to compare the variations of the indicators of scientific production and interest. Results: Through secondary data analysis, it was possible to establish indicators of general interest and scientific production. A discussion is presented on the evolution of sustainable development towards social responsibility. Conclusions: The results showed that the evolution of sustainable development towards social responsibility was not overcome through time, except in some moments and geographical places.

Context: The COVID-19 is the most recent global health concern that affects human health mainly the respiratory system with more than 170 million people affected by the virus worldwide. Also, Latin America has been emerging as an epicenter of contagion, and transmission is gradually increasing among the communities in each of the countries analyzed. The infection of more than 30 million people in Latin America supposes the construction of new models and habits of public health that promote attitudes to reduce the number of cases and mortality. Method: A proposal was defined based on three frameworks and models—the principle of healthy housing promoted by the Panamerican Health Organization, the four types of knowledge transfer without memorization proposed by the OECD, and the theory of social constructivism (in which knowledge is built from a present reality). This proposal is aims to help a community to understand the health risks present at home so that they can prevent the spread of the virus COVID-19 through the use of good practices. Results: The proposal shows categorized risk factors at home that increase the possibility of contagion of COVID- 19 and getting infected; also, it presents possible solutions to these factores, which focus on good practices of healthy housing to improve habitability and prevent diseases that also allow the virus to spread. Conclusions: It is necessary to implement strategies that humanize public health problems and that in turn include the knowledge that the field of engineering can contribute to solve these problems. In addition, these strategies must emerge from practical work focused on the community. An example of this is the proposal for good practices for healthy housing to prevent the spread of the COVID-19 virus.        

Context: Transmission lines are structures constructed of uniform material arranged as an array of conductor or semiconductor pairs to guide electromagnetic waves carrying radio frequency energy between a transmitting device and a receiving device. Its importance in communications lies in the knowledge of its fundamental parameters, which requires specialised measurement equipment and laboratory instruments to make important decisions on the coupling of technologies in data transmission systems. Methodology: To do so, a hardware and software architecture is created and implemented using analogue inputs to measure attenuation and digital and timed interruptions to measure the delay between the incident and transmitted waves, whose data are used to calculate characteristic impedance, attenuation constant, phase constant, propagation speed, resistance, conductance, capacitance and inductance, by means of experimental equations. Four experiments are carried out using 305 meters of coaxial cable, checking the data obtained with the manufacturer's theoretical data and validating with measurements of specialised specialized electronic instrumentation equipment, such as the function generator and the digital oscilloscope, with the aim of finding out the error of the proposed tool designed compared to advanced instruments. Results: As a result, a device is built that calculates the basic parameters of a transmission line with an error between 3 % and 9 % in the measurements. Conclusions: The developed tool delivers results close to the theoretical values and when compared with electronic measurement instruments (digital oscilloscope and function generator), it measures the characteristic impedance accurately; it presents a percentage error of 3.7 % when measuring the phase constant; and finally, it presents a percentage error of less than 9 % when measuring the attenuation constant, delay, propagation speed, resistance, conductance, capacitance and inductance. This determines that the maximum error of the measurements is 8.98 %, demonstrating that the proposed device developed is suitable for measuring the parameters of transmission lines. Financing: University of Pamplona.

Objective: To characterize the technological resources used by 10 professors who teach mathematics in industrial engineering and mechatronics programs at a Higher Education Institution (IES) in Barranquilla-Colombia during the Covid-19 pandemic. Methodology: This research was carried out under a qualitative approach and descriptive design, it was based on the subdomains technological knowledge of the content, technological knowledge and pedagogical technological knowledge of the teacher proposed in the TPACK model. Information was collected using instruments validated by the Delphi method such as virtual interviews and telephone calls. Next, aspects that gather the teacher's practice with respect to the use of technological resources used, knowledge and training of virtual education were transcribed in detail. Results: Significant findings were the reluctance to use technologies by the participants, little use of blackboards such as Idroop and Openboard, little training in specialized mathematics software such as GeoGebra, Geo TIC, Cabri, Matlab, among others. What limited the teaching process of the subjects (calculus I, calculus II, linear algebra, differential equations and numerical methods). Conclusion: It was concluded that due to the scarce interaction of teachers and students and that it led to the little pedagogical connotation that they attribute to the use of technological resources in their classes.

Context: When loading the product in the tanker trucks, hydrocarbon vapors are generated and released without treatment into the environment. To avoid these emissions, a system is required to retain and recover these substances through the use of an adsorbent capable of retaining the volatile organic compounds generated in the loading yard of the fuel distribution facility in Alto de Ochomogo, Cartago, Costa Rica Method: The composition of the displaced vapors was analyzed during the loading of clean product, and the removal and recovery effectiveness of two adsorbent matrices: Tenax® TA and Carbotrap® 317 was compared by modifying the standard method TO 17 of the United States Environmental Protection Agency. Results: With Tenax® TA, 93.8% removal was achieved; however, most of the trapped compounds consisted of chains greater than or equal to 7 carbon atoms. The tubes packed with Carbotrap® 317 removed 99.9% of the compounds in the sample, retaining compounds with chains less than 7 carbon atoms from gasoline vapors. The conditioning, entrapment and desorption conditions of the modified method allowed Carbotrap® 317 to successfully retain and recover compounds similar to those that are being lost during tank truck loading. Conclusions: The conditioning, sampling and desorption conditions of the modified method allowed the Carbotrap® 317 matrix to successfully retain and recover compounds similar to those that are being lost during tank truck loading.

Objective: To perform the classification and mapping of body sway parameters from static posturography data to differentiate unilateral transtibial amputees from non-amputees using machine learning and data mining techniques. Methodology: Body sway was measured in 74 individuals, 37 landmine amputees and 37 healthy controls. Stability was classified by group using five machine learning algorithms. A continuous two-dimensional map of posture alterations was developed using Shannon's information theory, the U Mann-Whitney test (p <0.05) was used to identify differences between groups. Results: Five machine learning algorithms (decision tree, decision rules, neural network, vector support machine and clustering) were trained. Validation and comparison were carried out with the metrics obtained from the confusion matrix, using cross-validation to obtain two subsets. The most discriminatory posture condition was classified as displacement of the center of pressure (CoP) on the non-amputated side, anteroposterior direction. The algorithm with the highest performance was the vector support machine and the one with the lowest performance was the cluster; however, all the models performed group classification with an F1 score greater than 0,4. Conclusions: Mapping of sway displacement characteristics into 2D space revealed clear clusters between amputees and controls, confirming that machine learning can aid in the classification of clinical sway patterns measured with static posturography. Computational models allow to objectively evaluate the stability, as well as to recognize the contribution of the contralateral in the control of the static bipedal posture, since it compensates for the non-existence of the ipsilateral afferents and efferents. Financing: Scientific research article derived from the research "Characterization of Stability in Unilateral Transtibial Amputees", funded by "Francisco José de Caldas District University".

Objective: This article presents an analysis of different optimization methodologies, which aims to make an objective comparison between metaheuristic and convex optimization methods in distribution networks, focusing on the inclusion of distributed generation (DG). The MATLAB software is used as a tool for implementation and obtaining results. The objective was to determine the optimal size of the DGs to be integrated into the networks, with the purpose of reducing the active power losses (objective function). Methodology: Based on the specialized literature, the methodologies are selected, and the bases and conditions for the implementation of the optimization techniques are determined. In the case of second-order cone programming (SOCP), the relaxation of the nonlinear optimal power flow (OPF) problem is performed in order to use convex optimization. Then, the structures of each technique are established and applied in the MATLAB software. Due to the iterative nature of metaheuristic methods, the data corresponding to 100 compilations for each algorithm are collected. Finally, by means of a statistical analysis, the optimal solutions for the objective function in each methodology are determined, and, with these results, the different methods applied to the networks are compared. Results: By analyzing 33- and 69-node systems, it is demonstrated that metaheuristic methods are able to effectively size DGs in distribution systems and yield good results that are similar and comparable to SOCP regarding the OPF problem. Genetic algorithms (GA) showed the best results for the studied implementation, even surpassing the SOCP. Conclusions: Metaheuristic methods proved to be algorithms with a high computational efficiency and are suitable for real-time applications if implemented in distribution systems with well-defined conditions. These techniques provide innovative ideas because they are not rigid algorithms, which makes them very versatile methods that can be adapted to any combinatorial optimization problem and software, yielding results even at the convex optimization level.

Objective: This article presents one of the Blockchain applications in power systems employing the electrical variables monitoring delivered by a simulated relay. Methodology: The electrical variables are verified, compared, and uploaded to a blockchain network created by a network of servers; these are responsible for uploading, validating, and exporting information to the system. This study is carried out through the Python programming language. Results: An algorithm capable of integrating these variables from a simulated relay is created, 4 servers are created that are in charge of taking the relay signals every minute, validating that they are unique in the blockchain and uploading them, the first node that completes this task uploads its identification and the information of the relay, the processing times of the information once obtained are approximately 10 seconds Conclusions: It is concluded that the algorithm is capable of decentralizing the information collected by the servers in times equal to or greater than one minute, which can be very useful when saving information, in applications such as control by the network operator it falls short by having times greater than or equal to one minute, it should be taken into account that, for the development of a blockchain with a greater number of equipment, it is advisable to use machines with high levels of processing, much higher RAM memories, these characteristics allow the algorithm to run smoothly and in the shortest possible time. Financing: Universidad Distrital Francisco José de Caldas