A virtual laboratory for multiagent systems: Joining efficacy, learning analytics and student satisfaction

[EN] This study introduces a distributed virtual laboratory for a multiagent programming course which has been very satisfactorily adopted by students, with a success rate of nearly 80%. It also aims at capturing the daily activity of students, providing the basis for data-driven assessment. Finally, it also allows for using process mining technologies to unveil successful and failed behaviors of students enabling the teacher for an early detection and intervention to improve their learning experience

The protection of foreign investment in Argentina

ABSTRACTThe purpose of this paper is to make a brief analysis of the regulation of foreign investment in Argentina at national, regional (MERCOSUR) and international le vel. Special attention will be given to the Argentine expropriation regime.Keywords: foreign investment, expropriation, mercosur. RESUMENEl objetivo de este artículo es analizar brevemente la regulación de las inversiones extranjeras en Argentina a  nivel nacional, regional (MERCOSUR) e internacional. Se prestará atención al régimen de expropiaciones en ArgentinaPalabras claves: inversiones extranjeras, expropiación, mercosur

Finding Differences among Construction Companies Management Practices and Their Relation to Project Performance

[EN] The performance of construction companies is linked to the performance of their projects because their financial success and the satisfaction of their clients depends on it. However, most studies of construction companies' performance consider mainly the corporate aspects but not the performance they achieve in their projects as a result of their management practices. A key issue is determining the differences among management practices used by construction companies that provide them with a competitive advantage, which was the purpose of this study. To achieve this goal, nine construction companies were selected for participation in this collaborative benchmarking study, and the management practices that differentiate the investigated construction companies were determined. The results highlight the relevance of the management of information and communication and the importance of lean management practices as the tools for analysis and planning or to improve processes. Construction companies' managers should consider these differentiating elements as a path to achieve competitive advantage.Castillo, T.; Alarcón, LF.; Pellicer, E. (2018). Finding Differences among Construction Companies Management Practices and Their Relation to Project Performance. Journal of Management in Engineering. 34(3):1-13. doi:10.1061/(ASCE)ME.1943-5479.0000606S11334

Power Line Inspection Via an Unmanned Aerial System Based on the Quadrotor Helicopter

The inspection of high voltage power transmission lines is mainly carried out by manned aerial vehicles or foot patrol. However, these maintenance methodologies for inspection are somehow inefficient and expensive. Moreover, helicopter assisted inspection endangers the human life. Recently, unmanned aerial vehicles have been under development in several research centers all over the world due to its potential applications. In this paper, we present an unmanned aerial system based on the quadrotor helicopter for high voltage power line inspection. Our interest is to equip the quadrotor helicopter with the necessary payload in order to be able to carry out a qualitative inspection, therefore the hardware architecture of the aerial robotic system is presented. Finally, some experimental results are shown to demonstrate the feasibility of the proposed system.ITESO, A.C

Experimental and computational study of conductivity of multilayer graphene in polypropylene nanocomposites

[EN] We study the electric conductivity of compounds formed by multilayer graphene in polypropylene. Our study makes a comparative analysis between the experimental and computational results. To obtain an experimental measurement of the electronic properties, we deposited multilayer graphene (MLG) nanoparticles over a polypropylene matrix. The deposition was made over several stages, in which we added to the polymer matrix different percentages of MLG nanoparticles using the melt compounding technique, and we studied the conductivities of the nanocomposites by means of electrochemical impedance spectroscopy (EIS). The second part consists of computational calculations, in which we studied the electronic properties of a graphene sheet under a polypropylene molecule with different slabs in the monomer. In both analyses, there is a strong percolation phenomenon with a percolation threshold of around 18% of the MLG nanoparticles. Before the percolation threshold, the charge carriers are constrained in the polypropylene molecule, making the system an insulating material and creating p-type doping. After the percolation threshold, the charge carriers are constrained in the graphene, making the system a conductor material and creating n-type doping with conductivity values of around 20 S m(-1). This phenomenon is a consequence of a change in the mechanism of charge transfer in the interface between the polypropylene molecule and graphene sheet. To describe the charge transfer mechanism, it is necessary to consider the quantum effect. The incorporation of the quantum effects and the percolation phenomenon make it possible for the theoretical conductivity to be close to the conductivity measured experimentally.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain. Also, the authors are grateful to UNAM-DGAPA-PAPIIT projects IG 100618 y IG 114818, DGTIC-UNAM for access to the Miztli-UNAM supercomputer LANCAD-UNAM-DGTIC-055, and UNAM-DGAPA for the Postdoctoral grant for Roxana M. del Castillo.Del Castillo, RM.; Del Castillo, LF.; Calles, AG.; Compañ Moreno, V. (2018). Experimental and computational study of conductivity of multilayer graphene in polypropylene nanocomposites. Journal of Materials Chemistry C. 6:7232-7241. https://doi.org/10.1039/c8tc01135dS723272416H. G. Karian , Handbook of polypropylene and polypropylene composites , RheTec, Inc. , Whitmore Lake, Michigan , 2nd edn, 2003 , https://books.google.es/books?hl=es&lr=&id=C0nzeNPUpoIC&oi=fnd&pg=PP1&dq=Handbook+of+polypropylene+and+polypropylene+composites&ots=LYqYBYg45n&sig=3gtYXigr8_O8CUJeefBCtGI7QXA#v=onepage&q=Handbook%20of%20polypropylene%20and%20polypropylene%20composites&f=falseRath, T., & Li, Y. (2011). Nanocomposites based on polystyrene-b-poly(ethylene-r-butylene)-b-polystyrene and exfoliated graphite nanoplates: Effect of nanoplatelet loading on morphology and mechanical properties. Composites Part A: Applied Science and Manufacturing, 42(12), 1995-2002. doi:10.1016/j.compositesa.2011.09.002Kim, M.-S., Yan, J., Kang, K.-M., Joo, K.-H., Kang, Y.-J., & Ahn, S.-H. (2013). Soundproofing ability and mechanical properties of polypropylene/exfoliated graphite nanoplatelet/carbon nanotube (PP/xGnP/CNT) composite. International Journal of Precision Engineering and Manufacturing, 14(6), 1087-1092. doi:10.1007/s12541-013-0146-3Zhang, K., Yu, H.-O., Shi, Y.-D., Chen, Y.-F., Zeng, J.-B., Guo, J., … Wang, M. (2017). Morphological regulation improved electrical conductivity and electromagnetic interference shielding in poly(l-lactide)/poly(ε-caprolactone)/carbon nanotube nanocomposites via constructing stereocomplex crystallites. Journal of Materials Chemistry C, 5(11), 2807-2817. doi:10.1039/c7tc00389gMohd Radzuan, N. A., Yusuf Zakaria, M., Sulong, A. B., & Sahari, J. (2017). The effect of milled carbon fibre filler on electrical conductivity in highly conductive polymer composites. Composites Part B: Engineering, 110, 153-160. doi:10.1016/j.compositesb.2016.11.021Li, Q., Yao, F.-Z., Liu, Y., Zhang, G., Wang, H., & Wang, Q. (2018). High-Temperature Dielectric Materials for Electrical Energy Storage. Annual Review of Materials Research, 48(1), 219-243. doi:10.1146/annurev-matsci-070317-124435Qiao, Y., Yin, X., Zhu, T., Li, H., & Tang, C. (2018). Dielectric polymers with novel chemistry, compositions and architectures. Progress in Polymer Science, 80, 153-162. doi:10.1016/j.progpolymsci.2018.01.003Rosehr, A., & Luinstra, G. A. (2017). Polypropylene composites with finely dispersed multi-walled carbon nanotubes covered with an aluminum oxide shell. Polymer, 120, 164-175. doi:10.1016/j.polymer.2017.05.045Bolotin, K. I., Sikes, K. J., Jiang, Z., Klima, M., Fudenberg, G., Hone, J., … Stormer, H. L. (2008). Ultrahigh electron mobility in suspended graphene. Solid State Communications, 146(9-10), 351-355. doi:10.1016/j.ssc.2008.02.024Banszerus, L., Schmitz, M., Engels, S., Goldsche, M., Watanabe, K., Taniguchi, T., … Stampfer, C. (2016). Ballistic Transport Exceeding 28 μm in CVD Grown Graphene. Nano Letters, 16(2), 1387-1391. doi:10.1021/acs.nanolett.5b04840Terrés, B., Chizhova, L. A., Libisch, F., Peiro, J., Jörger, D., Engels, S., … Stampfer, C. (2016). Size quantization of Dirac fermions in graphene constrictions. Nature Communications, 7(1). doi:10.1038/ncomms11528Zhang, H.-B., Zheng, W.-G., Yan, Q., Yang, Y., Wang, J.-W., Lu, Z.-H., … Yu, Z.-Z. (2010). Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding. Polymer, 51(5), 1191-1196. doi:10.1016/j.polymer.2010.01.027Chung, D. D. L. (2015). A review of exfoliated graphite. Journal of Materials Science, 51(1), 554-568. doi:10.1007/s10853-015-9284-6T. Bayerl , A.Benedito , A.Gallegos , G. B.Mitschang and B.Galindo , Melting of Polymer-Polymer Composites by Particulate Heating Promoters and Electromagnetic Radiation , in Synthetic Polymer-Polymer Composites , ed. D. Bhattacharyya and S. Fakirov , Carl HanserVerlag GmbH & Co. KG , 2012 , ch. 24, pp. 39–64 10.3139/9781569905258.002Harper, J., Price, D., & Zhang, J. (2005). Use of Fillers to Enable the Microwave Processing of Polyethylene. Journal of Microwave Power and Electromagnetic Energy, 40(4), 219-227. doi:10.1080/08327823.2005.11688543Galindo, B., Benedito, A., Gimenez, E., & Compañ, V. (2016). Comparative study between the microwave heating efficiency of carbon nanotubes versus multilayer graphene in polypropylene nanocomposites. Composites Part B: Engineering, 98, 330-338. doi:10.1016/j.compositesb.2016.04.082Asadi, K., Kronemeijer, A. J., Cramer, T., Jan Anton Koster, L., Blom, P. W. M., & de Leeuw, D. M. (2013). Polaron hopping mediated by nuclear tunnelling in semiconducting polymers at high carrier density. Nature Communications, 4(1). doi:10.1038/ncomms2708Fan, Z., Gong, F., Nguyen, S. T., & Duong, H. M. (2015). Advanced multifunctional graphene aerogel – Poly (methyl methacrylate) composites: Experiments and modeling. Carbon, 81, 396-404. doi:10.1016/j.carbon.2014.09.072Zabihi, Z., & Araghi, H. (2016). Monte Carlo simulations of effective electrical conductivity of graphene/poly(methyl methacrylate) nanocomposite: Landauer-Buttiker approach. Synthetic Metals, 217, 87-93. doi:10.1016/j.synthmet.2016.03.024Xia, X., Zhong, Z., & Weng, G. J. (2017). Maxwell–Wagner–Sillars mechanism in the frequency dependence of electrical conductivity and dielectric permittivity of graphene-polymer nanocomposites. Mechanics of Materials, 109, 42-50. doi:10.1016/j.mechmat.2017.03.014F. M. Bickelhaupt and E. J.Baerends , Kohn–Sham Density Functional Theory: Predicting and Understanding Chemistry . in Reviews in Computational Chemistry , 2007 , ed. K. B. Lipkowitz and B. Boyd Donald , John Wiley & Sons, Inc. , vol. 15, pp. 1–89 10.1002/9780470125922.ch1/summaryPerdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Methfessel, M., & Paxton, A. T. (1989). High-precision sampling for Brillouin-zone integration in metals. Physical Review B, 40(6), 3616-3621. doi:10.1103/physrevb.40.3616Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Files: C.pbe-van_ak.UPF, H.pbe-van_ak.UPF, N.pbe-van_ak.UPF, and O.pbe-van_ak.UPF, http://www.quantum-espresso.orgVanderbilt, D. (1990). Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. 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Science, 306(5696), 666-669. doi:10.1126/science.1102896Del Castillo, R. M., & Sansores, L. E. (2015). Study of the electronic structure of Ag, Au, Pt and Pd clusters adsorption on graphene and their effect on conductivity. The European Physical Journal B, 88(10). doi:10.1140/epjb/e2015-60001-2Galpaya, D., Wang, M., Liu, M., Motta, N., Waclawik, E., & Yan, C. (2012). Recent Advances in Fabrication and Characterization of Graphene-Polymer Nanocomposites. Graphene, 01(02), 30-49. doi:10.4236/graphene.2012.12005I. Zvyagin . Charge Transport via Delocalized States in Disordered Materials . in Charge Transport in Disordered Solids with Applications in Electronics , ed. S. Baranovsky , John Wiley & Sons, Inc. , 2006 , pp. 1–48 10.1002/0470095067.ch1/summaryLeenaerts, O., Partoens, B., & Peeters, F. M. (2009). Adsorption of small molecules on graphene. Microelectronics Journal, 40(4-5), 860-862. doi:10.1016/j.mejo.2008.11.022Hashemi, R., & Weng, G. J. (2016). A theoretical treatment of graphene nanocomposites with percolation threshold, tunneling-assisted conductivity and microcapacitor effect in AC and DC electrical settings. Carbon, 96, 474-490. doi:10.1016/j.carbon.2015.09.103Xia, X., Wang, Y., Zhong, Z., & Weng, G. J. (2017). A frequency-dependent theory of electrical conductivity and dielectric permittivity for graphene-polymer nanocomposites. Carbon, 111, 221-230. doi:10.1016/j.carbon.2016.09.078The determination of the elastic field of an ellipsoidal inclusion, and related problems. (1957). Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 241(1226), 376-396. doi:10.1098/rspa.1957.0133Trotta, S., Marmo, F., & Rosati, L. (2017). Evaluation of the Eshelby tensor for polygonal inclusions. Composites Part B: Engineering, 115, 170-181. doi:10.1016/j.compositesb.2016.10.018L. D. Landau , E. M.Lifshitz and L. 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La proteccion de las inversiones extranjeiras en Argentina. The protection of foreing investiment in Argentina

ABSTRACTThe purpose of this paper is to make a brief analysis of the regulation of foreign investment in Argentina at national, regional (MERCOSUR) and international level. Spec ial attention will be given to the Argentine expropriation regime.Keywords: foreign investment, expropriation, mercosur.RESUMENEl objetivo de este artículo es analizar brevemente la regulación de las inversiones extranjeras en Argentina a nivel nacional, regional (MERCOSUR) e internacional. Se prestará atención al régimen de expropiaciones en ArgentinaPalabras claves: inversiones extranjeras, expropiación, mercosur

Multi-mode Flight Sliding Mode Control System for a Quadrotor

There is a wide range of applications for unmanned aerial vehicles that requires the capability of having several and robust flight controllers available. This paper presents the main framework of a multimode flight control system for a quadrotor based on the super twisting control algorithm. The design stages for the four flight control modes encompassing manual, altitude, GPS fixed and autonomous mode are presented. The stability proof for each flight mode is carried out by means of Lyapunov functions while the stability analysis for the complete system, when a transition from one mode to another occurs, is demonstrated using the switching nonlinear systems theory. The performance of the proposed framework is demonstrated in a simulation study taking into account external disturbances.ITESO, A.C.CINVESTAV-IP

On-site forest fire smoke detection by low-power autonomous vision sensor

Early detection plays a crucial role to prevent forest fires from spreading. Wireless vision sensor networks deployed throughout high-risk areas can perform fine-grained surveillance and thereby very early detection and precise location of forest fires. One of the fundamental requirements that need to be met at the network nodes is reliable low-power on-site image processing. It greatly simplifies the communication infrastructure of the network as only alarm signals instead of complete images are transmitted, anticipating thus a very competitive cost. As a first approximation to fulfill such a requirement, this paper reports the results achieved from field tests carried out in collaboration with the Andalusian Fire-Fighting Service (INFOCA). Two controlled burns of forest debris were realized (www.youtube.com/user/vmoteProject). Smoke was successfully detected on-site by the EyeRISTM v1.2, a general-purpose autonomous vision system, built by AnaFocus Ltd., in which a vision algorithm was programmed. No false alarm was triggered despite the significant motion other than smoke present in the scene. Finally, as a further step, we describe the preliminary laboratory results obtained from a prototype vision chip which implements, at very low energy cost, some image processing primitives oriented to environmental monitoring.Ministerio de Ciencia e Innovación 2006-TIC-2352, TEC2009-1181

Autoimmune neurological conditions associated with Zika virus infection

Zika virus (ZIKV) is an emerging flavivirus rapidly spreading throughout the tropical Americas. mosquitoes is the principal way of transmission of the virus to humans. ZIKV can be spread by transplacental, perinatal, and body fluids. ZIKV infection is often asymptomatic and those with symptoms present minor illness after 3 to 12 days of incubation, characterized by a mild and self-limiting disease with low-grade fever, conjunctivitis, widespread pruritic maculopapular rash, arthralgia and myalgia. ZIKV has been linked to a number of central and peripheral nervous system injuries such as Guillain-Barré syndrome (GBS), transverse myelitis (TM), meningoencephalitis, ophthalmological manifestations, and other neurological complications. Nevertheless, mechanisms of host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion about the possible mechanisms underlying the development of autoimmune neurological conditions associated with Zika virus infection