Terminal terrestre multimodal en la ciudad de Zamora Arquitectura, movilidad y accesibilidad.

Zamora is a developing city like many Ecuadorian cities but it lack of a mobilization plan, which had lead to an uncontrolled growth of the city, which in less than a decade has a massive vehicular growth, also Zamora is a city that has many natural resources that offers work opportunities and attract many investors. The biggest problem of mobility that exists in the city of Zamora is given by the inadequate location of the bus terminal which is in the middle of the city, that's why through an analysis of the city I propose a new Multimodal bus terminal located in a new area that fits the accessibility and mobility problem of the city.Zamora es un ciudad en vías de desarrollo como muchas ciudades ecuatorianas sin embargo esta carece de un plan de movilización, lo que ha provocado un crecimiento descontrolado dentro de la ciudad; Es por eso que en menos de una década el crecimiento vehicular ha sido masivo e impactante, además Zamora es una ciudad que tiene muchos recursos naturales que ofrecen una gran cantidad de trabajo y atraen a muchos inversionistas. El mayor problema de movilidad que existe en la ciudad de Zamora se da por la presencia inadecuada del actual Terminal Terrestre en el centro de la ciudad, es por eso que por medio del análisis de la ciudad propongo un nuevo Terminal Terrestre Multimodal en un sitio que sea acorde con el problema de accesibilidad y movilidad de la ciudad.

Caminos desde el otro: el retorno a la “zona gris”

El texto pretende realizar un análisis del concepto de la Zona Gris presentado por Primo Levi. Para ello, se analizan tres tensiones fundamentales de su obra; a saber: (1) Los hundidos y los salvados; (2) Los diversos sujetos de enunciación y (3) mundo animal vs mundo civilizado

Lean Management Model. 5S implementation of the strategy for responsible Purchasing Department

El Departamento de Compras forma parte de la Cadena de Abastecimiento y es el responsable de la adquisición de bienes y/o servicios que una compañía requiere para su correcta operación, su responsabilidad está basada en negociar, verificar y mantener buenas relaciones con los proveedores, generando así un valor agregado al producto. De su efectividad depende el sobrecosto o el agotamiento del mismo; es por tal motivo que los Departamentos de Compras utilicen métodos que ayuden y hagan más eficientes sus procesos, para este caso se plantean pasos que conlleven a la implementación del Modelo Lean Management en el Departamento de Compras, por medio de una metodología de tipo descriptiva la cual se basa en la revisión bibliográfica de los más representativos expositores en la filosofía Lean Management, que permitan comprender el Modelo, sus ventajas y aplicabilidad al proceso de compras de la industria en general, gracias a su flexibilidad, orden y disciplina que logran desarrollar valor en los productos, la cual genera la tan anhelada satisfacción del cliente. Es allí donde modelos como el Lean Management son de utilidad, mejorando el proceso con suavidad y realizando un cambio en la mentalidad de los colaborares haciendo del Departamento de Compras dinámico y en continua mejora.The purchasing department belongs to the Supply Chain in a company. It is responsible for the procurement of goods and services that a company requires for a proper operation. Its liability is based on bargain and keeps good relations with suppliers, generating thus added value to the product. The effectiveness depends on the overrun or depletion thereof; is for this reason, that purchasing departments use methodologies in order to help that their processes become more efficient. This case of study provide the steps that lead to the implementation of the "Lean Management Model" in the purchasing department, through a descriptive methodology which is based on a literature review of the most representative exhibitors at the Lean Management philosophy. The methodology allows understand the model, its advantages and applicability to the procurement process in the general industry, thanks to its flexibility, order and discipline that develop value in products, increasing customer loyalty and its satisfaction. There is where models such as the Lean Management are useful, improving the process smoothly, and changing the doing mindset of the collaborates in the Purchasing Department, in a dynamic and continuous improvement

Zooplankton richness, abundance and biomass of two hypertrophic shallow lakes with different salinity

The zooplankton of lakes is controlled by biological and physico-chemical parameters. Among the former, predation by fish can determine the replacement of large-sized species by small-sized ones and among the latter, salinity exerts negative effects on richness and abundance. Since it has been suggested that saline lakes without fishes have higher zooplankton biomass than low salinity ones, the aim of this study was to determine the richness, abundance and biomass of zooplankton in two lakes with different salinity and test the hypothesis that in the presence of zooplanktivorous fishes and at equal concentrations of nutrients and chlorophyll a, saline lakes have higher biomass than those with low salinity. The study was conducted in two shallow lakes of the Province of La Pampa (central Argentina): a subsaline lake and a hyposaline lake, which shared high concentrations of chlorophyll a and total phosphorus, reduced transparency and presence of planktivorous fish. Zooplankton richness was different and higher in the subsaline lake, whereas abundance and total biomass were similar, even when the taxonomic groups were considered separately. It is suggested that the presence of a halotolerant planktivorous fish controlled the size of zooplankton due to the predation on larger species and prevented the development of higher biomass in the saline lake, which is an important difference from previously recorded situations. This study shows that, regardless of the differences in salinity, the top-down effect in the food chain may have been a factor that equalized the zooplankton biomass by allowing only the development of small species and highlights the possible importance of fish predation in determining chlorophyll a concentrations and water transparency.Fil: Echaniz, Santiago Andrés. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Vignatti, Alicia María. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cabrera, Gabriela Cecilia. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Jose, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Further Results on the Total Roman Domination in Graphs

[EN] Let G be a graph without isolated vertices. A function f:V(G)-> {0,1,2} is a total Roman dominating function on G if every vertex v is an element of V(G) for which f(v)=0 is adjacent to at least one vertex u is an element of V(G) such that f(u)=2 , and if the subgraph induced by the set {v is an element of V(G):f(v)>= 1} has no isolated vertices. The total Roman domination number of G, denoted gamma tR(G) , is the minimum weight omega (f)=Sigma v is an element of V(G)f(v) among all total Roman dominating functions f on G. In this article we obtain new tight lower and upper bounds for gamma tR(G) which improve the well-known bounds 2 gamma (G)<= gamma tR(G)<= 3 gamma (G) , where gamma (G) represents the classical domination number. In addition, we characterize the graphs that achieve equality in the previous lower bound and we give necessary conditions for the graphs which satisfy the equality in the upper bound above.Cabrera Martínez, A.; Cabrera García, S.; Carrión García, A. (2020). Further Results on the Total Roman Domination in Graphs. Mathematics. 8(3):1-8. https://doi.org/10.3390/math8030349S1883Henning, M. A. (2009). A survey of selected recent results on total domination in graphs. Discrete Mathematics, 309(1), 32-63. doi:10.1016/j.disc.2007.12.044Henning, M. A., & Yeo, A. (2013). Total Domination in Graphs. Springer Monographs in Mathematics. doi:10.1007/978-1-4614-6525-6Henning, M. A., & Marcon, A. J. (2016). Semitotal Domination in Claw-Free Cubic Graphs. Annals of Combinatorics, 20(4), 799-813. doi:10.1007/s00026-016-0331-zHenning, M. . A., & Marcon, A. J. (2016). Vertices contained in all or in no minimum semitotal dominating set of a tree. Discussiones Mathematicae Graph Theory, 36(1), 71. doi:10.7151/dmgt.1844Henning, M. A., & Pandey, A. (2019). Algorithmic aspects of semitotal domination in graphs. Theoretical Computer Science, 766, 46-57. doi:10.1016/j.tcs.2018.09.019Cockayne, E. J., Dreyer, P. A., Hedetniemi, S. M., & Hedetniemi, S. T. (2004). Roman domination in graphs. Discrete Mathematics, 278(1-3), 11-22. doi:10.1016/j.disc.2003.06.004Stewart, I. (1999). Defend the Roman Empire! Scientific American, 281(6), 136-138. doi:10.1038/scientificamerican1299-136Chambers, E. W., Kinnersley, B., Prince, N., & West, D. B. (2009). Extremal Problems for Roman Domination. SIAM Journal on Discrete Mathematics, 23(3), 1575-1586. doi:10.1137/070699688Favaron, O., Karami, H., Khoeilar, R., & Sheikholeslami, S. M. (2009). On the Roman domination number of a graph. Discrete Mathematics, 309(10), 3447-3451. doi:10.1016/j.disc.2008.09.043Liu, C.-H., & Chang, G. J. (2012). Upper bounds on Roman domination numbers of graphs. Discrete Mathematics, 312(7), 1386-1391. doi:10.1016/j.disc.2011.12.021González, Y., & Rodríguez-Velázquez, J. (2013). Roman domination in Cartesian product graphs and strong product graphs. Applicable Analysis and Discrete Mathematics, 7(2), 262-274. doi:10.2298/aadm130813017gLiu, C.-H., & Chang, G. J. (2012). Roman domination on strongly chordal graphs. Journal of Combinatorial Optimization, 26(3), 608-619. doi:10.1007/s10878-012-9482-yAhangar Abdollahzadeh, H., Henning, M., Samodivkin, V., & Yero, I. (2016). Total Roman domination in graphs. Applicable Analysis and Discrete Mathematics, 10(2), 501-517. doi:10.2298/aadm160802017aAmjadi, J., Sheikholeslami, S. M., & Soroudi, M. (2019). On the total Roman domination in trees. Discussiones Mathematicae Graph Theory, 39(2), 519. doi:10.7151/dmgt.2099Cabrera Martínez, A., Montejano, L. P., & Rodríguez-Velázquez, J. A. (2019). Total Weak Roman Domination in Graphs. Symmetry, 11(6), 831. doi:10.3390/sym1106083

PWM Control of a Buck Converter with an Amorphous Core Coil

Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented

Using the Own Flexibility of a Climbing Robot as a Double Force Sensor

Force sensors are used when interaction tasks are carried out by robots in general, and by climbing robots in particular. If the mechanics and electronics systems are contained inside the own robot, the robot becomes portable without external control. Commercial force sensors cannot be used due to limited space and weight. By selecting the links material with appropriate stiffness and placing strain gauges on the structure, the own robot flexibility can be used such as force sensor. Thus, forces applied on the robot tip can be measured without additional external devices. Only gauges and small internal electronic converters are necessary. This paper illustrates the proposed algorithm to achieve these measurements. Additionally, experimental results are presented

Sintonización robusta de controladores PID utilizando estimación no lineal

Los controladores PID, dispositivos ampliamente utilizados en sistemas industriales cada vez requieren un mayor desarrollo dentro de su implementación debido a que los procedimientos de producción, con la adopción de más tecnología e innovación, son cada vez más sofisticados. Los sistemas de control requieren entonces de desarrollos complejos que satisfagan las necesidades del medio. Los sistemas industriales y de procesos se basan en diferentes medios para entregar mejores resultados de producción y así satisfacer cualquier nivel de demanda. Es importante entonces la aplicación de técnicas y metodologías de estimación de sistemas que permitan modelar procesos y dispositivos con el fín de conocer su respuesta dinámica en el tiempo. En el presente documento se describe un procedimiento para la sintonización de forma robusta de controladores PID convencionales. Se pretende el mejoramiento de la realización de las acciones de control y optimizar el cálculo de este tipo de controladores entendiendo que, por el momento, siguen siendo los más utilizados en el control de procesos. Además de esto se plantea la metodología para estimación no lineal de sistemas de primer y segundo orden, y se muestra la con fiabilidad de los resultados obtenidos a través de la aplicación uso de un método recursivo no lineal

Determinantes del comercio entre Ecuador y los países integrantes de la Unión Europea

This paper seeks to identify the significant variables in trade between Ecuador and the European Union. Through literature review, we highlight the importance of this work to expose the existing commercial relationship between the European Union and the countries of Latin America and the Caribbean, especially with Ecuador. The results of gravity models highlight the importance of migration, trade liberalization and population, while pointing the insignificance of variables such as distance, religion and language.El presente trabajo busca identificar las variables significativas en el comercio entre Ecuador y la Unión Europea. Por medio de la revisión de la literatura, resaltamos la importancia del presente trabajo al exponer la relación comercial existente entre la Unión Europea y los países de América Latina y el Caribe, especialmente con Ecuador. Los resultados de los modelos de gravedad resaltan la importancia de la migración, la apertura comercial y la población, mientras que señalan la insignificancia de variables como la distancia, la religión e idioma