A modified Schwinger's formula for the Casimir effect

After briefly reviewing how the (proper-time) Schwinger's formula works for computing the Casimir energy in the case of "scalar electrodynamics" where the boundary conditions are dictated by two perfectly conducting parallel plates with separation "a" in the Z-axis, we propose a slightly modification in the previous approach based on an analytical continuation method. As we will see, for the case at hand our formula does not need the use of Poisson summation to get a (renormalized) finite result.Comment: 6 pages, DFTUZ/93/14 (a short version will appear in the Letters in Math. Phys.

An Implemented of a Real-Time Experimental Setup for Robotic Teleoperation System

The development of this work presents the implementation of an experimental platform, which will permit to investigate on a methodology for the design and analysis of a teleoperated system, considering the delay in the communication channel. The project has been developed in partnership with the laboratory of Automatic and Robotics of the Universidad Politécnica de Madrid and the Laboratory at the Centro de Tecnologías Avanzadas de Manufactura at the Pontificia Universidad Católica del Perú. The mechanical structure of the arm that is located in the remote side has been built and the electric servomechanism has been mounted to control their movement. The experimental test of the Teleoperation system has been developed. The PC104 card commands the power interface and sensors of the DC motor of each articulation of the arm. Has developed the drives for the management of the operations of the master and the slave: send/reception of position, speed, acceleration and current data through a CAN network. The programs for the interconnection through a LAN network, between the Windows Operating System and the Real-time Operating System (QNX), has been developed. The utility of the developed platform (hardware and software) has been demonstrated

Motion and Trajectories of Particles Around Three-Dimensional Black Holes

The motion of relativistic particles around three dimensional black holes following the Hamilton-Jacobi formalism is studied. It follows that the Hamilton-Jacobi equation can be separated and reduced to quadratures in analogy with the four dimensional case. It is shown that: a) particles are trapped by the black hole independently of their energy and angular momentum, b) matter alway falls to the centre of the black hole and cannot understake a motion with stables orbits as in four dimensions. For the extreme values of the angular momentum of the black hole, we were able to find exact solutions of the equations of motion and trajectories of a test particle.Comment: Plain TeX, 9pp, IPNO-TH 93/06, DFTUZ 93/0

Predicting mobile apps spread: An epidemiological random network modeling approach

[EN] The mobile applications business is a really big market, growing constantly. In app marketing, a key issue is to predict future app installations. The influence of the peers seems to be very relevant when downloading apps. Therefore, the study of the evolution of mobile apps spread may be approached using a proper network model that considers the influence of peers. Influence of peers and other social contagions have been successfully described using models of epidemiological type. Hence, in this paper we propose an epidemiological random network model with realistic parameters to predict the evolution of downloads of apps. With this model, we are able to predict the behavior of an app in the market in the short term looking at its evolution in the early days of its launch. The numerical results provided by the proposed network are compared with data from real apps. This comparison shows that predictions improve as the model is fed back. Marketing researchers and strategy business managers can benefit from the proposed model since it can be helpful to predict app behavior over the time anticipating the spread of an appAlegre-Sanahuja, J.; Cortés, J.; Villanueva Micó, RJ.; Santonja, F. (2017). Predicting mobile apps spread: An epidemiological random network modeling approach. Transactions of the Society for Computer Simulation. 94(2):123-130. https://doi.org/10.1177/0037549717712600S12313094

Non-parametric probabilistic forecasting of academic performance in Spanish high school using an epidemiological modelling approach

Academic underachievement is a concern of paramount importance in Europe, and particularly in Spain, where around of 30% of the students in the last two courses in high school do not achieve the minimum knowledge academic requirement. In order to analyze this problem, we propose a mathematical model via a system of ordinary differential equations to study the dynamics of the academic performance in Spain. Our approach is based on the idea that both, good and bad study habits, are a mixture of personal decisions and influence of classmates. Moreover, in order to consider the uncertainty in the estimation of model parameters, a bootstrapping approach is employed. This technique permits to forecast model trends in the next few years using confidence intervals. Unfortunately, the obtained results do not suggest improvement in academic performance for the coming years.Cortés López, JC.; Sánchez Sánchez, A.; Santonja, FJ.; Villanueva Micó, RJ. (2013). Non-parametric probabilistic forecasting of academic performance in Spanish high school using an epidemiological modelling approach. Applied Mathematics and Computation. 221(15):648-661. doi:10.1016/j.amc.2013.06.070S6486612211

The dynamics over the next few years of the Spanish mobile telecommunications market share: a mathematical modelling approach

This is an author's accepted manuscript of an article published in: “Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences"; Volume 20, Issue 6, 2014; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1080/13873954.2013.843572Taking into account available data from 2002 to 2009 about the market share percentages of the Spanish mobile telecommunications service providers, a dynamic diffusion model to study the evolution of the clients’ change between the different companies during the period 2010–2016 is proposed. The constructed model provides a tool for forecasting short-term trends about the customers’ preferences with respect to mobile network operators taking into account both, autonomous decisions due to direct marketing and advertising strategies, and also decisions adopted through interaction via social influence. The model can provide insights to companies for designing strategies in order to gain market share.This work has been partially supported by the FIS PI-10/01433; the Spanish Government and European Regional Development Fund (FEDER) [grant number MTM2009-08587]; and the Universitat Politecnica de Valencia [grant number PAID06-11-2070].Cervelló Royo, RE.; Cortés, J.; Santonja, F.; Villanueva Micó, RJ. (2014). The dynamics over the next few years of the Spanish mobile telecommunications market share: a mathematical modelling approach. Mathematical and Computer Modelling of Dynamical Systems. 20(6):557-565. https://doi.org/10.1080/13873954.2013.843572S557565206Gruber, H. (1999). An investment view of mobile telecommunications in the European Union. Telecommunications Policy, 23(7-8), 521-538. doi:10.1016/s0308-5961(99)00042-7Cortés, J.-C., Lombana, I.-C., & Villanueva, R.-J. (2010). Age-structured mathematical modeling approach to short-term diffusion of electronic commerce in Spain. Mathematical and Computer Modelling, 52(7-8), 1045-1051. doi:10.1016/j.mcm.2010.02.030Gruber, H. (2001). Competition and innovation. Information Economics and Policy, 13(1), 19-34. doi:10.1016/s0167-6245(00)00028-7Gruber, H., & Verboven, F. (2001). The diffusion of mobile telecommunications services in the European Union. European Economic Review, 45(3), 577-588. doi:10.1016/s0014-2921(00)00068-4Bettencourt, L. (1997). Customer voluntary performance: Customers as partners in service delivery. Journal of Retailing, 73(3), 383-406. doi:10.1016/s0022-4359(97)90024-5Herrera-González, F., & Castejón-Martín, L. (2009). The endless need for regulation in telecommunication: An explanation. Telecommunications Policy, 33(10-11), 664-675. doi:10.1016/j.telpol.2009.07.001Santonja, F.-J., Morales, A., Villanueva, R.-J., & Cortés, J.-C. (2012). Analysing the effect of public health campaigns on reducing excess weight: A modelling approach for the Spanish Autonomous Region of the Community of Valencia. Evaluation and Program Planning, 35(1), 34-39. doi:10.1016/j.evalprogplan.2011.06.00

The effect of the Spanish Law of Political Parties (LPP) on the attitude of the Basque Country population towards ETA: A dynamic modelling approach

In June 2002, the Spanish Government passed the ¿Law of Political Parties¿ (LPP) with the aim, among others, of preventing parties giving political support to terrorist organizations. This law affected the Basque nationalist party ¿Batasuna¿, due to its proved relation with ETA. In this paper, taking data from the Euskobarometro (Basque Country survey) related to the attitude of the Basque population towards ETA, we propose a dynamic model for the pre-LPP scenario. This model will be extrapolated to the future in order to predict what would have happened to the attitude of the Basque population if the law had not been passed. These model predictions will be compared to post-LPP data from the Euskobarometro using a bootstrapping approach in order to quantify the effect of the LPP on the attitude of Basque Country population towards ETA.Peco Yeste, M.; Santonja, F.; Tarazona Tornero, AC.; Villanueva Micó, RJ.; Villanueva Oller, FJ. (2013). The effect of the Spanish Law of Political Parties (LPP) on the attitude of the Basque Country population towards ETA: A dynamic modelling approach. Mathematical and Computer Modelling. 1-7. doi:10.1016/j.mcm.2011.11.007S1

Schwinger's Method for the Massive Casimir Effect

We apply to the massive scalar field a method recently proposed by Schwinger to calculate the Casimir effect. The method is applied with two different regularization schemes: the Schwinger original one by means of Poisson formula and another one by means of analytical continuation.Comment: plain TeX, 6 pages, DFTUZ-93-2

Predicting the academic underachievement in high school in Spain over the next few years: A dynamic modelling approach

[EN] In this paper we propose a dynamic model to understand the evolution of the academic underachievement in a high school in Spain. This model is based on ideas of Christakis and Fowler where individual habits may be transmitted by social contact. Thus, to build the model we suppose that a student has academic failure when she/he gets into study habits transmitted by students with bad academic habits. From the available academic results of the Spanish high school educational system during the period 1999 2008, we fit the model to the data in order to obtain the parameters of the model. Then, we predict the academic underachievement evolution over the next few years.This work has been partially supported by the Spanish M.C.Y.T. grant MTM2009-08587 and the Universitat Politecnica de Valencia grant PAID06-09-2588Camacho Vidal, FJ.; Cortés, J.; Micle, RM.; Sánchez-Sánchez, A. (2013). Predicting the academic underachievement in high school in Spain over the next few years: A dynamic modelling approach. Mathematical and Computer Modelling. 57(7):1703-1708. https://doi.org/10.1016/j.mcm.2011.11.011S1703170857