Universidad de Medellín

Repositorio Institucional Universidad de Medellín
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    5257 research outputs found

    Use of information and communication technologies in journalistic writing and development of critical thinking [Uso de las tecnologías de información y comunicación en la escritura periodística y desarrollo del pensamiento crítico1]

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    School journalism with Information and Communication Technologies was implemented to improve critical thinking in secondary school students; the critical thinking was measured using a pretest-posttest and control group quasi-experimental design. ICTs were used, since writing and rewriting work and also consulting reliable sources, a basic element of critical thinking, is more viable when using technology. Digital databases and computer programs were used for the edition and layout of the newspaper, as well as social media for interactions. The experimental group made school newspapers collaboratively and the control group did not; when comparing their scores, it was found that those who produced newspapers using ICTs increased their critical thinking score by six times compared with the control group. These differences are statistically significant, so there is empirical evidence to affirm that the use of ICT favors the development of critical thinking since they generate collaborative environments that motivate writing. © 2020, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved

    The social discount rate and the environment [La tasa social de descuento y el medio ambiente]

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    [No abstract available

    Multi-Messenger Physics With the Pierre Auger Observatory

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    An overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results are reviewed, such as stringent upper bounds that were placed to a flux of diffuse cosmogenic neutrinos and photons, bounds placed on neutrinos emitted from compact binary mergers that were detected by LIGO and Virgo during their first and second observing runs, as well as searches for high energy photons and neutrons from the Galactic center that constrain the properties of the putative Galactic PeVatron, observed by the H.E.S.S. collaboration. The observation of directional correlations between ultra-high energy cosmic rays and either high energy astrophysical neutrinos or specific source populations, weighted by their electromagnetic radiation, are also discussed. They constitute additional multi-messenger approaches aimed at identifying the sources of high energy cosmic rays. © Copyright © 2019 Kampert, Alejandro Mostafa, Zas and The Pierre Auger Collaboration

    PID tuning method based on IMC for inverse-response second-order plus dead time processes

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    This work addresses a set of tuning rules for PID controllers based on Internal Model Control (IMC) for inverse-response second-order systems with dead time. The transfer function, and some time-response characteristics for such systems are first described. Then, the IMC-based methodology is developed by using an optimization objective function that mixes performance and robustness. A correlation that minimizes the objective function and that allows the user to compute the controller's tuning parameter is found. The obtained expressions are mathematically simple, which facilitate their application in a ten-step systematic methodology. Finally, the proposed tuning method is compared to other well-known tuning rules that have been reported in literature, for a wide range of parameters of the process. The performance achieved with the proposed method is very good not only for disturbance rejection but for set-point tracking, when considering a wide-range of parameters of the process' transfer function. © 2020 by the authors

    Formulations for joint order picking problems in low-level picker-to-part systems

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    This article introduces several mathematical formulations for the joint order picking problem (JOPP) in low-level picker-to-part warehousing systems. In order to represent real warehousing environments, the proposed models minimize performance measures such as travel distance, travel time and tardiness, considering multi-block warehouses, due dates, and multiple pickers. The number of constraints and decision variables required for each proposed model is calculated, demonstrating the complexity of solving medium and long-sized problems in reasonable computing time using exact methods, so it is still recommendable to solve these JOPP using metaheuristics. The proposed models can be followed as a reference for new solution methods that yield efficient and fast solutions. © 2020, Institute of Advanced Engineering and Science. All rights reserved

    A new way for comparing solutions to non-technical electricity losses in South America

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    Non-technical losses are a component of energy losses associated with energy theft and fraud by the final consumers, hindering revenues of distribution utilities. This paper aims to compare the implemented solutions in the countries of South America to reduce non-technical losses. In this comparison, we introduce a new indicator based on the World Bank's database as input information. Considering that some regulatory agencies take policy actions related to non-technical losses to improve the quality of the electricity supply, we also present a correlation analysis of the proposed indicator and the electricity supply quality index. This analysis shows that in most of South America's countries, there is a high correlation within the studied horizon. An adequate characterization of the temporal variation in the proposed indicator can characterize the evolution of the consumers' perception of the quality in the electricity supply. This indicator allows each country's regulatory agency to analyze how the performed action is reducing non-technical losses concerning neighboring countries. © 2020 Elsevier Lt

    Exploration of serious games on environmental issues

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    Nowadays, the environmental problems for which the world is going through has generated several actions aimed at generating environmental education, using various means to achieve it. One of the tools that education and publicity among other areas are using are serious games, which has gained popularity, being used in various sectors such as education, trade, health, environment and others because they add entertainment to communication processes or educational. Serious games are used as one way to sensitize people about the depletion of natural resources and the consequences of environmental imbalance. Serious games are used as one means to sensitize people about the depletion of natural resources and the consequences of environmental imbalance. This article presents an exploration of serious games focused on environmental issues as well as identifying some of its features and opportunities for improvement. This paper presents a serious exploration of games applied to the area of education and environmental awareness, identifying elements that will be useful when developing technological tools such as initiatives and innovations in environmental education is presented. © Springer Nature Switzerland AG 2018

    Social innovation: Evolution of the concept over time [Innovación social: Evolución del concepto en el tiempo]

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    This article aims to characterize innovation based on the evolution it has had over time, and emphasizing the measurement criteria used between 2016 and 2018. In the first instance, elements are needed to understand the phenomenon and its different meanings, and then carry out a comparative review between sources and existing proposals. Data mining and qualitative analysis of the categories selected in the study were applied, supported by information from databases such as Scopus, Web of Science and Scielo. The exercise was carried out with the support of the Technological Surveillance and Competitive Intelligence Program of the Center for Research for Development and Innovation of the Universidad Pontificia Bolivariana, supplemented with specific searches. The main findings show trends compared to authors and types of metrics used in our context, which allows showing the growing importance of social innovation and its measurements at the level of results, effects and impacts, as part of the scientific work in the Latin American social field. © 2020, Universidad del Zulia. All rights reserved

    LO-Phonons and dielectric polarization effects on the electronic properties of doped GaN/InN spherical core/shell quantum dots in a nonparabolic band model

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    The electron energy spectrum of a core/shell spherical quantum dot made of zincblende GaN/InN compounds is investigated taking into account the presence of an off-center donor atom and the influence of band nonparabolicity. The interaction of both the charge carrier and the Coulombic core with longitudinal optical phonons is included through Frö hlich and Aldrich-Bajaj theories, respectively. The ground state energy is determined by solving the resulting conduction band effective mass equation via the variational Ritz principle. A detailed analysis of the features of electron and hole spectra as functions of the core and shell sizes is presented, highlighting the possibility of transitioning between type-I and type-II structures. A detailed discussion about the effects of conduction band nonparabolicity, dielectric mismatch and electron-phonon interaction onto the impurity binding energy is provided. It was found that, in general, nonparabolicity of the conduction band leads to larger impurity binding energy, and that LO-phonon and dielectric mismatch effects tend to reduce the value of the latter quantity. © 2021, Springer-Verlag GmbH Germany, part of Springer Nature


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