Time filter

Source Type

Mexico City, Mexico

Castellanos-Lopez S.L.,CINVESTAV | Cruz-Perez F.A.,CINVESTAV | Rivero-Angeles M.E.,UPIITA IPN | Hernandez-Valdez G.,Metropolitan Autonomous University
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC | Year: 2013

Due to the unpredictable nature of channel availability, supporting the quality of service (QoS) of stringent delay sensitive traffic in cognitive radio networks (CRNs) is very challenging. Stringent delay sensitive calls in CRNs are susceptible to forced termination due to the preemptive resource occupancy priority of primary users. To enable more efficient usage of the spectrum while improving the QoS experienced by secondary users (SUs), dynamic spectrum leasing (and coordinated cognitive radio) of resources has been previously proposed in the literature. In this paper, the Erlang capacity in coordinated cognitive radio networks with real-time hard delay constraint traffic as function of the rented resources is analytically calculated. For the adequate and fair performance comparison, call admission with fractional channel reservation to prioritize ongoing secondary calls over new ones is considered. From numerical results, it is observed that in CRNs exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, delay sensitive services cannot be even supported in cognitive radio networks. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by delay sensitive services. Then, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated. © 2013 IEEE.

Barcenas M.,TESE | Douda J.,UPIITA IPN | Duda Y.,Mexican Institute of Petroleum | Orea P.,Mexican Institute of Petroleum
Journal of Chemical Physics | Year: 2010

An extended particle agglomeration control model and Monte Carlo simulation methodology were used to describe the behavior of the colloidal aggregation process in presence of inhibitor as a confined fluid. In this work results about the mean cluster size, Z, with respect to different variables, temperature, inhibitor concentration and pore size, are presented and showed that Z strongly depends on the slitlike pore size. In addition, a temperature interval where the heating of the system leads to the particle clustering was found. © 2010 American Institute of Physics.

Kontorovich V.,CINVESTAV | Lovtchikova Z.,UPIITA IPN
Studies in Computational Intelligence | Year: 2013

Nowadays chaotic modelling of real phenomena in electrical engineering problems, particularly in communications, control, etc, is a topic of growing interest. Therefore, the filtering of chaos is one of the most important techniques for many applications including those which are related to real-time regime conditions. These applications include, but are not limited to chaos-based communication system synchronization, real-time control of chaos, radio-frequency interference filtering and mitigation, chaotic system identification, etc. This chapter presents among well known original results of a study of nonlinear filtering of chaotic signals in presence of additive white Gaussian noise (AWGN) and related topics. © 2013 Springer-Verlag Berlin Heidelberg.

Ramirez-Neria M.,CINVESTAVIPN | Sira-Ramirez H.,CINVESTAV | Luviano-Juarez A.,UPIITA IPN | Rodrguez-Angeles A.,CINVESTAV
Asian Journal of Control | Year: 2015

In this article, the problem of robust trajectory tracking, for a parallel robot is tackled via an observer-based active disturbance rejection controller. The proposed design method is based on purely linear disturbance observation and linear feedback control techniques modulo nonlinear input gain injections and cancellations. The estimations are carried out through Generalized Proportional Integral (GPI) observers, endowed with output integral injection to ease the presence of possible zero mean measurement noise effects. As the lumped (both exogenous and endogenous) disturbance inputs are estimated, they are being used in the linear controllers for on-line disturbance cancellation, while the phase variables are being estimated by the same GPI observer. The estimations of the phase variables are used to complete a linear multivariable output feedback controller. The proposed control scheme does not need the exact knowledge of the system, which is a good alternative to classic control schemes such as computed torque method, reducing the computation time. The estimation and control method is approximate, ensuring small as desired reconstruction and tracking errors. The reported results, including laboratory experiments, are better than the results provided by the classical model-based techniques, shown to be better when the system is subject to endogenous and exogenous uncertainties. © 2014 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd.

Puga S.,UPIITA IPN | Bonilla M.,CINVESTAV | Malabre M.,CNRS Research Institute of Communication and Cybernetics of Nantes
Proceedings of the IEEE Conference on Decision and Control | Year: 2010

This paper considers the problem of stabilizing a single input-single output linear time varying system using a low order controller and equalizer filter. The closed loop system is a linear singularly perturbed system with uniform asymptotic stability behavior; we calculate bounds ε ∈ 2 (0; ε*) as in [9], such that the uniform asymptotic stability of the singularly perturbed system is guaranteed. Following the results of [9] we show how to design a control law such that the system dynamics is assigned by a Hurwitz polynomial with constant coefficients. ©2010 IEEE.

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