Agent Based Models of Language Competition: Macroscopic descriptions and Order-Disorder transitions

We investigate the dynamics of two agent based models of language competition. In the first model, each individual can be in one of two possible states, either using language $X$ or language $Y$, while the second model incorporates a third state XY, representing individuals that use both languages (bilinguals). We analyze the models on complex networks and two-dimensional square lattices by analytical and numerical methods, and show that they exhibit a transition from one-language dominance to language coexistence. We find that the coexistence of languages is more difficult to maintain in the Bilinguals model, where the presence of bilinguals in use facilitates the ultimate dominance of one of the two languages. A stability analysis reveals that the coexistence is more unlikely to happen in poorly-connected than in fully connected networks, and that the dominance of only one language is enhanced as the connectivity decreases. This dominance effect is even stronger in a two-dimensional space, where domain coarsening tends to drive the system towards language consensus.Comment: 30 pages, 11 figure

Anomalous lifetime distributions and topological traps in ordering dynamics

We address the role of community structure of an interaction network in ordering dynamics, as well as associated forms of metastability. We consider the voter and AB model dynamics in a network model which mimics social interactions. The AB model includes an intermediate state between the two excluding options of the voter model. For the voter model we find dynamical metastable disordered states with a characteristic mean lifetime. However, for the AB dynamics we find a power law distribution of the lifetime of metastable states, so that the mean lifetime is not representative of the dynamics. These trapped metastable states, which can order at all time scales, originate in the mesoscopic network structure.Comment: 7 pages; 6 figure

An Interactive and comprehensive software tool to promote active learning in the Loop Shaping Control System design

The classical loop shaping is a design procedure that explicitly involves the shaping of the open loop transfer function L(s), within a desired frequency spectrum by manipulating the poles, zeros, and gain of the controller C(s). Interactive software tools have proven as, particularly, useful techniques with high impact on control education. This kind of interactive tools has demonstrated in the past that students learn in a much more active way. This paper presents the basic functionality of the linear control system design (LCSD), an interactive tool for analysis and design of linear control systems with special emphasis on the classical loop shaping design. The software tool is implemented in Sysquake, a MATLAB-like language with fast execution and excellent facilities for interactive graphics, and is delivered as a stand-alone executable that is readily accessible to students and instructors. Several design problems are used to illustrate the main features of the LCSD tool to perform classical loop shaping.Postprint (published version

High gain observer with dynamic deadzone to estimate liquid water saturation in PEM fuel cells

[EN] In the area of PEM fuel cells, water management remains one of the most challenging issues affecting PEMFC efficiency and lifetime. Liquid water active control and supervision techniques are limited by the absence of online sensors that can estimate the liquid water saturation. For this reason, this work presents the design of a state observer to estimate the cathode catalyst layer's liquid water saturation of an open-cathode PEM fuel cell. The proposed observer is based on High-Gain techniques, and is modified with a dynamic dead-zone which reduces the observer's noise sensibility. The results have been validated through numerical simulation and experiments. It is shown that, in the absence of noise, the proposed observer presents a similar performance than its non dead-zone equivalent. Moreover, in the presence of noise, the dead-zone significantly reduces the estimation error induced by it.[ES] En el campo de las pilas de combustible PEM, la gestión de agua líquida es una de las problemáticas más importantes que afectan a la eficiencia y vida útil del sistema. Las técnicas de control activo y supervisión del agua se ven limitadas por la ausencia de sensores que puedan medir la saturación de agua líquida en línea. Por eso, en este trabajo se presenta el diseño de un observador de estado para la estimación de la saturación de agua líquida en la capa catalizadora del cátodo de una pila de combustible PEM de cátodo abierto. El observador propuesto se basa en técnicas de alta ganancia. Además, se modifica con una función de zona muerta autoajustable con el fin de reducir su sensibilidad al ruido en la medida. Los resultados se han validado mediante simulación numérica y experimentación. Estos muestran que, en ausencia de ruido, el observador propuesto presenta unas prestaciones similares a las de su equivalente sin zona muerta. Además, en presencia de ruido, la zona muerta disminuye significativamente el error de estimación inducido por este.Este proyecto se ha financiado parcialmente por el proyecto DOVELAR (ref. RTI2018-096001-B-C32). Este trabajo se ha realizado con el apoyo de la Agencia Estatal de Investigación española a través del sello de excelencia de María de Maeztu, IRI (MDM-2016-0656). Este trabajo se ha financiado parcialmente por AGAUR of Generalitat de Catalunya a través de la subvención del grupo Advanced Control Systems (SAC) (2017 SGR 482). Este trabajo se ha realizado con el apoyo de ACCIÓ (Operational Program FEDER Catalunya 2014-2020) a través de REFER project (COMRDI15-1-0036-11).Cecilia, A.; Costa-Castelló, R. (2020). Observador de alta ganancia con zona muerta ajustable para estimar la saturación de agua líquida en pilas de combustible tipo PEM. Revista Iberoamericana de Automática e Informática industrial. 17(2):169-180. https://doi.org/10.4995/riai.2020.12689OJS16918017

Trends in scientific research on climate change in agriculture and forestry subject areas (2005-2014)

[EN] The term "Climate change" involves an alteration of the mean and variability of the climate properties. It implies unusual variations in the planet earth atmosphere, which causes related effect on other parts of the planet. The reduction in the land crops annual yield is derived from those alterations. The objective of this paper was to contribute to a better understanding of the scientific knowledge of climate change and its effect concerning agriculture and investigate its evolution through published papers. The items under study were obtained from the Web of Science (WOS) platform from Thomson Reuters. A bibliometric and social network analysis was performed to determine the indicators of scientific productivity, impact and collaboration between authors, institutions and countries. A subject analysis taking into account the key words assigned to papers and subject areas of journals was also carried out. A total of 1471 articles were included in the selected subject categories in WOS from 2005 until 2014. More than 50% of the papers were published in the last three years. The papers were published in 302 different journals. The United States Department of Agriculture (USDA) is the most productive institution (n = 70), followed by the Chinese Academy of Sciences (n = 58) and the Institut National de la Recherche Agronomique (INRA, France) (n = 47). The Canadian Forest Service has the most citations (n = 1456). The most frequent keywords were CO2, adaptation, model, temperature and impact. The network of collaboration between institutions and countries involve both centres from developed and developing countries and the central position of the United States, together with other leading countries, such as China, Canada, Australia, Germany, and the United Kingdom. Twenty papers received more than 100 citations, most of them concerned with emerging risks that climate change causes on forests, the impact on the forest ecosystems, the effect on plant diseases and adaptation options.Aleixandre-Benavent, R.; Aleixandre-Tudó, JL.; Castelló-Cogollos, L.; Aleixandre Benavent, JL. (2017). Trends in scientific research on climate change in agriculture and forestry subject areas (2005-2014). Journal of Cleaner Production. 147:406-418. https://doi.org/10.1016/j.jclepro.2017.01.112S40641814

Librería Java para análisis y simulación de sistemas lineales

[Resumen] Este proyecto presenta el diseño, implementación y algunos ejemplos de uso de una librería JAVA pensada para el análisis y simulación de sistemas lineales. Se ha diseñado pensando en que sea fácilmente integrable con Easy Java Simulations. El uso combinado de ambas herramientas facilita el desarrollo de laboratorios virtuales y remotos.Este trabajo ha sido parcialmente financiado por el proyecto DPI2015-69286-C3-2-R (MINECO/FEDER) y el proyecto 2014 SGR 267 de la AGAUR (agencia de la Generalitat de Catalunya)Generalitat de Catalunya; 2014 SGR 267https://doi.org/10.17979/spudc.978849749808

Broad lifetime distributions for ordering dynamics in complex networks

We search for conditions under which a characteristic time scale for ordering dynamics towards either of two absorbing states in a finite complex network of interactions does not exist. With this aim, we study random networks and networks with mesoscale community structure built up from randomly connected cliques. We find that large heterogeneity at the mesoscale level of the network appears to be a sufficient mechanism for the absence of a characteristic time for the dynamics. Such heterogeneity results in dynamical metastable states that survive at any time scale.Comment: 8 pages, 12 figure

Effect of alkali doping on CIGS photovoltaic ceramic tiles

This report studies the influence of alkali elements (Na, K) to morphological, structural and optoelectronic properties of CIGS ceramic tile solar cell. Several ceramic enamels with altered chemical composition in terms of amount of alkali elements have been tested and compared. The influences of alkali type, its quantity and transfer mechanism have been investigated. The solar cell device has been assembled and characterized. The achieved results indicate that alkali elements (Na and K combination) modified the surface roughness and its diffusion from the enamel toward the absorber affect to the structural and final optoelectronic properties of the device. The alkali doping improve the Ga incorporation in the crystal lattice and an increasing in open circuit voltage (Voc) values, fill factor (FF) and the device efficiency. Optimal alkali quantities have been also determined. The best conversion efficiency is achieved for the cell with 4% wt Na2O and 3.2 % wt K2O (Eff. = 3,5 %), which presents an improvement of 30 % in efficiency relative to the standard (STD) solar cell sample chosen for comparative purposes

Tools for teaching digital control in engineering degrees

[EN] This work describes a set of teaching materials that have been developed to support the learning of digital control. In particular, it presents a set of interactive tools and the project Duino-Based Learning (DBL) that has been designed to develop experimental practices of digital control using Arduino. In addition, the paper depicts the contents of a digital control course, taught in the framework of an industrial engineering degree, and how the developed tools are used in its teaching.[ES] En este trabajo se describen un conjunto de materiales pedagógicos que han sido desarrollados para dar soporte a la docencia del control digital. En particular, se presentan un conjunto de herramientas interactivas y el proyecto Duino-Based Learning (DBL) pensado para desarrollar prácticas experimentales de control digital utilizando Arduino. Además, se describe el contenido de un curso de control digital, que  se imparte en el marco de una titulación de ingeniería industrial, y como se utilizan las diferentes herramientas desarrolladas en su docencia.El trabajo de E. Lerma ha sido financiado por la donación de Mathworks UPC-I-01523. El trabajo de R. Griñó ha sido parcialmente financiado por el Gobierno de España a través de la Agencia Estatal de Investigación Proyecto DPI2017-85404-P, la Generalitat de Catalunya a través del Proyecto 2017 SGR 872 y la donación de Mathworks UPC-I-01523. El trabajo de R. Costa-Castelló ha sido parcialmente financiado por el Gobierno de España a través de la Agencia Estatal de Investigación Proyecto DOVELAR ref. RTI2018-096001-B-C32 (MCIU/AEI/FEDER, UE) y “María de Maeztu Seal of Excellence to IRI” (MDM-2016-0656), la Generalitat de Catalunya a través del Proyecto 2017 SGR 482 y la donación de Mathworks UPC-I-01523.Lerma, E.; Costa-Castelló, R.; Griñó, R.; Sanchis, C. (2021). Herramientas para la docencia de control digital en grados de ingeniería. Revista Iberoamericana de Automática e Informática industrial. 18(2):193-203. https://doi.org/10.4995/riai.2020.13756OJS193203182Barber, R., Horra, M., Crespo, J., 2013. Practices using simulink with arduino as low cost hardware. IFAC Proceedings Volumes 46 (17), 250 - 255. https://doi.org/10.3182/20130828-3-UK-2039.00057Basañez, L., Caminal, P., 2002. Control digital: problemas. Edicions UPC.Basañez, L., Costa, R., Fossas, E., Mañanas, M. A., Puig, V., Riera, J., Rosell, J., Villà, R., 2013. Treballs pràctics de control digital (in Catalan). CPDA.Candelas, F., García, G., Puente, S., Pomares, J., Jara, C., Pérez, J., Mira, D., Torres, F., 2015. Experiences on using arduino for laboratory experiments of automatic control and robotics. IFAC-PapersOnLine 48 (29), 105 - 110. https://doi.org/10.1016/j.ifacol.2015.11.221Costa Castelló, R., Fossas, E., 2014. Sistemes de Control en Temps Discret. Edicions UPC, ISBN: 978-84-9880-492-8.Diaz, J. M., Costa-Castelló, R., Dormido, S., Oct 2019. Closed-loop shaping linear control system design: An interactive teaching/learning approach [focus on education]. IEEE Control Systems Magazine 39 (5), 58-74.Dormido, S., Dormido-Canto, S., Dormido, R., Sánchez, J., Duro, N., 2005. The role of interactivity in control learning. Int. J. Eng. Educ. 21 (6), 1122-1133.Guzmán, J.L., Costa Castelló, R., Berenguel, M., Dormido, S., 2012. Control automático con herramientas interactivas. Pearson. ISBN: 9788483227503Guzmán, J. L., Costa-Castelló, R., Dormido, S., Berenguel, M., Feb 2016. An interactivity-based methodology to support control education: How to teach and learn using simple interactive tools [lecture notes]. IEEE Control Systems 36 (1), 63-76. https://doi.org/10.1109/MCS.2015.2495092Jury, E., 1958. Sampled-data Control Systems. John Wiley and Sons.Jury, E., 1973. Theory and Application of the z-Transform Method. Krieger Pub. Co.Kuo, B., 1995. Digital Control Systems. Oxford University Press.Lerma, E., Griñó, R., Costa-Castelló, R., Sanchis, C., 5-7 de Septiembre de 2018. Implementación de controladores en arduino mediante simulink. In: EXTREMADURA, U. D. (Ed.), Actas de las XXXVIII Jornadas de Automática. CEA, Badajoz, pp. 158-164.Longchamp, R., 2006. Comande Num'eriques de Syst'emes Dynamiques. Cours d'Automatique. Presses Polytechniques et Universitaires Romandes.Ogata, K., 1994. Discrete-time Control Systems. Prentice Hall.Ogata, K., 2015. Modern Control Engineering. Pearson India.Phillips, C., Nagle, T., Brickley, J., Chakrabortty, A., 2014. Digital Control System Analysis & Design. Pearson Education Ltd.Piguet, Y., 2018. Sysquake Pro User Manual. Calerga Sarl, Lausanne, Switzerland.Rubio, J., García, E., Aquino, G., Aguilar-Ibáñez, C., Pacheco, J., Meda-Campaña, J.A., 2019. Mínimos cuadrados recursivos para un manipulador que aprende por demostración. Revista Iberoamericana de Automática e Informática industrial 16, 147-158. https://doi.org/10.4995/riai.2019.8899Ruiz, A. P., Rivas, M. A., Harbour, M. G., 2019. Aplicaciones ada en android con requisitos de tiempo real. Revista Iberoamericana de Automática e Informática industrial 16 (3), 264-272. https://doi.org/10.4995/riai.2019.10604Sobota, J., PiSl, R., Balda, P., Schlegel, M., 2013. Raspberry pi and arduino boards in control education. IFAC Proceedings Volumes 46 (17), 7 - 12. https://doi.org/10.3182/20130828-3-UK-2039.00003Tou, J., 1959. Digital and Sampled-data Control Systems. McGraw-Hill Inc