En este trabajo se presenta una comparación de los tiempos de respuesta, optimización de la ruta y complejidad del grafo en métodos de planificación de trayectoria para robots móviles autónomos. Se contrastan los desarrollos de Voronoi, Campos potenciales, Roadmap probabilístico y Descomposición en celdas para la navegación en un mismo entorno y validándolos para un número variable de obstáculos. Las evaluaciones demuestran que el método de generación de trayectoria por Campos Potenciales, mejora la navegación respecto de la menor ruta obtenida, (...) el método Rapidly Random Tree genera los grafos de menor complejidad y el método Descomposición en celdas, se desempeña con menor tiempo de respuesta y menor coste computacional. Palabras Clave: optimización, trayectoria, métodos de planificación, robots móviles. Referencias [1]H. Ajeil, K. Ibraheem, A. Sahib y J. Humaidi, “Multi-objective path planning of an autonomous mobile robot using hybrid PSO-MFB optimization algorithm, ” Applied Soft Computing, vol. 89, April 2020. [2]K.Patle, G. Babu, A. Pandey, D.R.K. Parhi y A. Jagadeesh, “A review: On path planning strategies for navigation of mobile robot,” Defence Technology, vol. 15, pp. 582-606, August 2019. [3]T. Mack, C. Copot, D. Trung y R. De Keyser, “Heuristic approaches in robot path planning: A survey,” Robotics and Autonomous Systems, vol. 86, pp. 13-28, December 2016. [4]L. Zhang, Z. Lin, J. Wang y B. He, “Rapidly-exploring Random Trees multi-robot map exploration under optimization framework,” Robotics and Autonomous Systems, vol. 131, 2020. [5]S. Khan y M. K. Ahmmed, "Where am I? Autonomous navigation system of a mobile robot in an unknown environment," 2016 5th International Conference on Informatics, Electronics and Vision, pp. 56-61, December 2016. [6]V. Castro, J. P. Neira, C. L. Rueda, J. C. Villamizar y L. Angel, "Autonomous Navigation Strategies for Mobile Robots using a Probabilistic Neural Network," IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society, pp. 2795-2800, Taipei, 2007. [7]Y. Li, W. Wei, Y. Gao, D. Wang y C. Fan, “PQ-RRT*: An improved path planning algorithm for mobile robots,” Expert Systems with Applications, vol. 152, August 2020. [8]A. Muñoz, “Generación global de trayectorias para robots móviles, basada en curvas betaspline,” Dep. Ingeniería de Sistemas y Automática Escuela Técnica Superior de Ingeniería Universidad de Sevilla, 2014. [9]H. Montiel, E. Jacinto y H. Martínez, “Generación de Ruta Óptima para Robots Móviles a Partir de Segmentación de Imágenes,” Información Tecnológica, vol. 26, 2015. [10] C. Expósito, “Los diagramas de Vornooi, la forma matemática de dividir el mundo,” Dialnet, Diciembre 2016. (shrink)

This work presents results of improvement in the productivity of Arthrospira platensis in a company dedicated to its production. The six sigma methodology was applied in production processes that require the use of bioreactors. Starting from the analysis of the current state, aspects, physical and chemical variables that directly influence the productivity achieved were identified. Various culture media were tested and subsequently scaled for industrial production. In addition, the incorporation of carbon into the culture medium was controlled, optimizing the range (...) of potential hydrogen pH. The identified parameters were measured and six sigma methodology strategies were assigned. An improvement in productivity corresponding to 66% was verified with the same quality of final product. Keywords: Six sigma, Bioreactors, Productivity, Arthrospira platensis. References [1]E. Ariawan and A. Makalew, “Smart Micro Farm: Sustainable Algae Spirulina Growth Monitoring System” in 10th International Conference on Information Technology and Electrical Engineering, Bali, 2018, pp.1-4. [2]L. Socconini and C. Reato, Lean six sigma: sistema de gestión para liderar empresas. Primera edición. Barcelona: Marge Books, 2019. [3]H. Gutiérrez, Calidad and productividad. Cuarta edición. México D.F.: McGraw-Hill Interamericana, 2014. [4]G. Usharani, P. Saranraj and D. Kanchana, “Spirulina Cultivation: A Review” in International Journal of Pharmaceutical & Biological Archives, vol. 3, no. 6, pp. 1327-1336, December 2012. [5]J. Udin, O. Gani, A. Mahato, I. Sakib and M. Rakiuzzaman, SPIRULINA PRODUCTION IN DIFFERENT PHOTOBIOREACTORS ON ROOFTOP, International Journal of Business, Social and Scientific Research, vol. 8, no. 1, pp. 15-19, January 2020. [6]M. Arredondo, Contabilidad y análisis de costos. Primera edición. México D.F.: Grupo Editorial Patria, 2015. [7]J. García, Contabilidad de costos. Cuarta edición. México D.F.: McGraw-Hill Interamericana, 2014. [8]L. Socconini, Certificación Lean Six Sigma Green Belt para la excelencia en los negocios. Primera edición. Barcelona: Marge Books, 2015. [9]A. Vian, Introducción a la Química Industrial. Segunda edición. Buenos Aires: Reverté, 2012. [10]S. Milton, Estadística para Biología y Ciencias de la Salud. Tercera edición. Madrid: McGraw-Hill Interamericana, 2014. (shrink)

The current times call for reforms in educational processes. The Covid-19 pandemic had an unforeseen impact on the educational system in all countries. This need for change requires new pedagogies and new methods for teaching and learning. Understanding the need for change is essential for the formulation of adaptive proposals, as well as for the generation of training activities to complement the teaching curriculum. New educational practices lead to a vision of educational quality, with new approaches that allow the continuous (...) integration of knowledge and permanent interaction with the student. This paper presents an analysis of the new teaching methodologies in times of confinement due to the pandemic caused by Covid-19. Keywords: Teaching methodologies, educational system, learning process. References [1]É. Tremblay-Wragg, C. Raby, L. Ménard y I. Plante, «El uso de estrategias didácticas diversificadas por cuatro profesores universitarios: ¿qué contribución a la motivación de aprendizaje de sus alumnos?,» Docencia en educación superior, vol. 26, nº 21, 2021. [2]L. Czerniewicz, R. Mogliacci, S. Walji, A. Cliff, B. Swinnerton y N. Morris, «Enseñanza y aprendizaje académico en el nexo: desagregación, mercantilización y digitalización en la educación superior,» Teaching in Higher Education, vol. 26, nº 2021, p. 16, 2021. [3]S. Dogan y A. Adam, «Aumentar el efecto del desarrollo profesional en la instrucción efectiva a través de comunidades profesionales,» Docentes y docencia: teoría y práctica, vol. 26, nº 3-4, pp. 326-349, 2020. [4]I. M. Torres Salas, «La enseñanza tradicional de las ciencias versus las nuevas tendencias educativas,» Educare, vol. 14, nº 1, pp. 131-142, 2010. [5]B. Fabio, J. Antonio Palomino y J. González Henríquez, «Evaluación y contraste de los métodos de enseñanza tradicional y lúdico,» Revista de Educación física y deportes, vol. 13, nº 94, pp. 29-36, 2008. [6]Y. Benítez y C. Mora, «Enseñanza tradicional vs aprendizaje activo,» Revista Cubana de Física, vol. 27, nº 2A, pp. 175-179, 2010. [7]P. Morales Bueno y V. Landa Fitzgerald, «Aprendizaje basado en problemas,» Theoria, vol. 13, nº 1, pp. 145-157, 2004. [8]R. Gil-Galván, I. Martín-Espinosa y F. Gil-Galván, «University student perceptions of competences acquired through problem-based learning,» Educación XXI, vol. 24, nº 1, pp. 271-295, 2020. [9]E. Ortiz Cermeño, «El aprendizaje basado en problemas,» Perfiles Educativos, vol. 41, nº 164, pp. 208-213, 2019. [10]E. Araos-Baeriswyl, C. Moll-Manzur, Á. Paredes y J. Landeros, «Aprendizaje invertido: un enfoque pedagógico en tiempos de pandemia,» Rev. Atención Primaria, vol. 53, nº 1, p. 117, 2021. [11]V. León-Carrascosa, M. Belando-Montoro y S. Sánchez-Serrano, «Design and validation of a questionnaire to evaluate the service-learning methodology,» Rev.Estudios sobre educación, vol. 39, nº 1, pp. 247-266, 2020. [12]J. Collado-Ruano, M. Ojeda, M. Malo y D. Amino, «Educación, arte e interculturalidad: El cine documental como lenguaje comunicativo y tecnología innovadora para el aprendizaje de la metodología I + D + I,» Rev. Texto livre, vol. 13, nº 3, pp. 376-393, 2020. [13]P. M. Bueno y V. Landa Fitzgerald, «Aprendizaje basado en problemas,» Theoria, vol. 13, nº 1, pp. 145-157, 2004. [14]J. A. Martí, M. Heydrich, M. Rojas y A. Hernández, «Aprendizaje basado en proyectos: Una experiencia de innovación docente,» Universidad EAFIT, vol. 46, nº 158, pp. 11-21, 2010. [15]L. Rojas y N. M. Jaimes, «Canvas LMS y el trabajo colaborativo como metodología de aprendizaje en entornos virtuales,» de Congreso Ibérico de Sistemas y Tecnologías de la Información, CISTI, Bogotá, Colombia, 2020. [16]B. Bordel y P. Mareca, «Results and Trends in educational MOOCs in the engineering area with MIRIADAX platform. A case study,» de 15th Iberian Conference on Information Systems and Technologies, CISTI 2020; Seville; Sevilla, España, 2020. [17]K. Vermeir y G. Kelchtermans, «Innovative practice as interpretative negotiation.A case-study on the kamishibai in Kindergarten.,» Teachers and Teaching: Theory and Practice, vol. 26, nº 3-4, pp. 248-263, 2020. [18]B. Tucker, «The Flipped Classroom: Online instruction at home frees class time for learning,» Education Next, vol. 1, nº 1, pp. 82-84, 2012. [19]M. V. Ledo, N. R. Michelena, N. N. Cao, I. d. R. M. Suárez y M. N. Vialart Vidal, « Aula invertida, nueva estrategia didáctica,» Educación Médica Superior, vol. 30, nº 3, pp. 678-688, 2016. [20]Metodologías activas por medio de las TIC, [Online]. Available: https://www.campuseducacion.com/blog/recursos/articulos-campuseducacion metodologias-activas-por-medio-de-las-tic/?cn-reloaded=1. [Last access: February 14, 2021]. (shrink)

According to the prevailing sentiment, changing the past is logically impossible. The prevailing sentiment is wrong. In this paper, I argue that the claim that changing the past entails a contradiction ultimately rests upon an empirical assumption, and so the conclusion that changing the past is logically impossible is to be resisted. I then present and discuss a model of time which drops the empirical assumption and coherently models changing the past. Finally, I defend the model, and changing the past, (...) against objections. (shrink)

G. C. J. Midgley; XIV—Linguistic Rules, Proceedings of the Aristotelian Society, Volume 59, Issue 1, 1 June 1959, Pages 271–290, https://doi.org/10.1093/aristot.

Some philosophers argue that any attempt to model changing the past will either be contradictory or really model avoiding the past. Using Nicholas Smith's (1997) argument as a basis, I formulate a generic version of this Avoidance Argument. I argue that the Avoidance Argument fails because (i) it involves an equivocation of what is meant by ‘bifurcation of the time of an event’ and (ii) resolving the equivocation results in the falsity of at least one of the premises. Hence, the (...) Avoidance Argument will not support the claim that changing the past is logically impossible. (shrink)

We apply the distinction between parameter independence and outcome independence to the linear and nonlinear models of a recent nonrelativistic theory of continuous state vector reduction. We show that in the nonlinear model there is a set of realizations of the stochastic process that drives the state vector reduction for which parameter independence is violated for parallel spin components in the EPR-Bohm setup. Such a set has an appreciable probability of occurrence (≈ 1/2). On the other hand, the linear model (...) exhibits only extremely small parameter dependence effects. We investigate some specific features of the models and we recall that, as has been pointed out recently, if one wants to be able to speak of definite outcomes (or equivalently of possessed objective elements of reality) at finite times, one has to slightly change the criteria for their attribution to physical systems. The concluding section is devoted to a detailed discussion of the difficulties which one meets when one tries to take, as a starting point for the formulation of a relativistic theory, a nonrelativistic scheme which exhibits parameter dependence. Here we derive a theorem which identifies the precise sense in which the occurrence of parameter dependence forbids a genuinely relativistic generalization. Finally we show how the appreciable parameter dependence of the nonlinear model gives rise to problems with relativity, while the extremely weak parameter dependence of the linear model does not give rise to any difficulty, provided one takes into account the appropriate criteria for the attribution of definite outcomes. (shrink)

We analyse a recent paper in which an alleged devastating criticism of the so called GRW proposal to account for the objectification of the properties of macroscopic systems has been presented and we show that the author has not taken into account the precise implications of the GRW theory. This fact makes his conclusions basically wrong. We also perform a survey of measurement theory aimed to focus better on the physical and the conceptual aspects of the so-called macro-objectification problem.

On Indic philosophy, with reference to topics in Buddhism and Vedanta; articles.

Chris Mortensen, Graham Nerlich, Garrett Cullity and Gerard O'Brien.

These documents, published here for the first time, present the Treasury's counter-arguments during the period when Keynes was developing the ideas that led to the Keynesian revolution in economic policy. Keynes spent much effort trying to persuade the Treasury to adopt policies designed to raise employment and stabilise prices, and to create an international monetary system that would favour these objectives. His arguments are set out fully in the Royal Economic Society's 30-volume set of The Collected Writings of John Maynard (...) Keynes. In contrast, the views of his Treasury critics have hitherto been much less accessible.Economists and historians have tended to assume that Keynes was right and the Treasury was wrong; this volume shows that the Treasury anticipated the political problems that would be encountered in putting Keynes's ideas into practice. Much of what Keynes published was deliberately polemical: he believed that words should be 'a little wild', for they were 'the assault of thought on the unthinking'. Treasury officials were by no means as unthinking as Keynes tended to portray them, and they had a coherent and intellectually respectable understanding of public finance. Ministers in the inter-war period and early in the Second World War were sensitive to the use that political opponents might make of Keynes's arguments; officials had to provide counter-arguments, and in doing so they revealed much about their views on economics and public finance. Once Keynes became an adviser to the Chancellor of the Exchequer in 1940, the debate became internal to the Treasury, but officials continued to subject Keynes's ideas to critical analysis.The documents in this volume show Treasury responses to Keynes on a range of issues crucial to understanding the period and the context of the Keynesian revolution in public policy. The topics covered include: the return to the gold standard; the use of public expenditure to cure unemployment in the inter-war period; how to avoid inflation in the war; planning for the post-war international economy; and the 1944 white paper on employment policy. This edition is an essential tool for the study of a formative period of British history and a great intellectual debate. (shrink)

David Hitchcock, in his recent “Informal Logic and the Concept of Argument”, defends a recursive definition of ‘argument.’ I present and discuss several problems that arise for his definition. I argue that refining Hitchcock’s definition in order to resolve these problems reveals a crucial, but minimally explicated, relation that was, at best, playing an obscured role in the original definition or, at worst, completely absent from the original definition.

It is hardly necessary to recapitulate Rhys Roberts' cumulative and convincing proof that the treatise ‘On the Sublime’ was not written by Cassius Longinus, the tutor of Zenobia, but belongs to the early days of the Empire. Not the least convincing of the arguments for this date is the fact that the treatise is suggested by and put out as a substitute for the Περ ״ϒψоνς of Caecilius of Calacte, who according to Suidas taught rhetoric in Rome in the time (...) of Augustus. Now Caecilius was an intimate friend of Dionysius of Halicarnassus : they were both Atticists and fellow-workers in leading literary Romans back to the best models of Greek prose style. But Dionysius is no candidate for the authorship of the extant treatise, which is not one that he could have written. On the other hand he gives a plain indication by which to identify its writer, which Rhys Roberts mentioned but did not adopt. It is the object of this paper to put this identification seriously forward. (shrink)