Mexican Center for Research and Advanced Studies

www.cinvestav.mx
Mexico City, Mexico

The Center for Research and Advanced Studies of the National Polytechnic Institute is a Mexican non-governmental scientific research affiliated to the National Polytechnic Institute and founded by president Adolfo López Mateos on 17 April 1961, initially planned as a posgraduate department of the National Polytechnic Institute, which was later modified by President José López Portillo, on the 17 September 1982.The modification by President Portillo stipulates that it is a decentralized organ of public interest, with legal personality and own patrimony. Cinvestav receives an annual subsidy by the Federal Government to fund its operations. Wikipedia.

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Clempner J.,National Polytechnic Institute of Mexico | Poznyak A.,Mexican Center for Research and Advanced Studies
International Journal of Applied Mathematics and Computer Science | Year: 2011

We introduce the concept of a Lyapunov game as a subclass of strictly dominated games and potential games. The advantage of this approach is that every ergodic system (repeated game) can be represented by a Lyapunov-like function. A direct acyclic graph is associated with a game. The graph structure represents the dependencies existing between the strategy profiles. By definition, a Lyapunov-like function monotonically decreases and converges to a single Lyapunov equilibrium point identified by the sink of the game graph. It is important to note that in previous works this convergence has not been guaranteed even if the Nash equilibrium point exists. The best reply dynamics result in a natural implementation of the behavior of a Lyapunov-like function. Therefore, a Lyapunov game has also the benefit that it is common knowledge of the players that only best replies are chosen. By the natural evolution of a Lyapunov-like function, no matter what, a strategy played once is not played again. As a construction example, we show that, for repeated games with bounded nonnegative cost functions within the class of differentiable vector functions whose derivatives satisfy the Lipschitz condition, a complex vector-function can be built, where each component is a function of the corresponding cost value and satisfies the condition of the Lyapunov-like function. The resulting vector Lyapunov-like function is a monotonic function which can only decrease over time. Then, a repeated game can be represented by a one-shot game. The functionality of the suggested method is successfully demonstrated by a simulated experiment.


Alvarado M.,Mexican Center for Research and Advanced Studies | Rendon A.Y.,Mexican Center for Research and Advanced Studies
Expert Systems with Applications | Year: 2012

In multi-player games, the Nash Equilibrium (NE) profile concept deserves a team for selecting strategies during a match, so no player - except in own prejudice - individually deviates from the team selected strategy. By using NE strategy profiles, the way a baseball team increases the possibilities to a match victory is payoff-matrices-based analyzed in this paper. Each matrix entry arrange each player's strategies by regarding the ones from mates and adversaries, and posterior to a NE-profile-selection, the matrix from all players strategies can support the manager's strategic decision-making in the course of a match. A finite state machine, a formal grammar and a generator of random plays are the algorithmic fundament for this collective strategic reasoning automation. The relationships to e-commerce, social and political scopes, as well as to computing issues are reviewed. © 2012 Elsevier Ltd. All rights reserved.


Schnoor M.,Mexican Center for Research and Advanced Studies
Journal of Immunology | Year: 2015

The endothelium is the first barrier that leukocytes have to overcome during recruitment to sites of inflamed tissues. The leukocyte extravasation cascade is a complex multistep process that requires the activation of various adhesionmolecules and signaling pathways, as well as actin remodeling, in both leukocytes and endothelial cells. Endothelial adhesion molecules, such as E-selectin or ICAM-1, are connected to the actin cytoskeleton via actin-binding proteins (ABPs). Although the contribution of receptor-ligand interactions to leukocyte extravasation has been studied extensively, the contribution of endothelial ABPs to the regulation of leukocyte adhesion and transendothelial migration remains poorly understood. This review focuses on recently published evidence that endothelial ABPs, such as cortactin, myosin, or α-actinin, regulate leukocyte extravasation by controlling actin dynamics, biomechanical properties of endothelia, and signaling pathways, such as GTPase activation, during inflammation. Thus, ABPs may serve as targets for novel treatment strategies for disorders characterized by excessive leukocyte recruitment. Copyright © 2015 by The American Association of Immunologists, Inc. 0022-1767/15/$25.00.


Rocha L.,Mexican Center for Research and Advanced Studies
Pharmacology and Therapeutics | Year: 2013

In spite of the high success rate of many surgical procedures for pharmacoresistant epilepsy, a substantial number of patients do not become seizure-free. Different strategies for electrical modulation of the brain such as Deep Brain Stimulation, Vagal Nerve Stimulation and Transcraneal Magnetic Stimulation have gained considerable interest in the last decade as alternative therapies for patients with medically refractory epilepsy. Research into the mechanism of action of the strategies for electrical modulation of the brain suggests a crucial role of different molecules and channels such as glutamate, γ-aminobutyric acid, adenosine, brain-derived neurotrophic factor, calcium channels, sodium channels as well as extracellular potassium. Electrical modulation of the brain may reduce the overexpression of P-glycoprotein, a drug efflux transporter that reduces the absorption of antiepileptic drugs. Electrical modulation of the brain induces long-term effects associated with beneficial consequences on clinical symptoms observed during the postictal state. In addition, electrical modulation of the brain might also promote the neurogenesis in subjects with pharmacoresistant epilepsy in whom this process is decreased. Targeting the regulatory pathways in charge of the effects of electrical modulation of the brain is discussed as a means to improve its efficacy. Electrical modulation of the brain combined with pharmacotherapy may represent an innovative approach to avoid epileptogenesis, reduce seizure activity, induce beneficial effects during the postictal state, diminish the amount of antiepileptic drugs, and improve alertness, memory and mood in pharmacoresistant epilepsy. © 2013 Elsevier Inc.


Clempner J.B.,Center for Economics | Poznyak A.S.,Mexican Center for Research and Advanced Studies
Journal of Systems Science and Systems Engineering | Year: 2014

In this paper, we present a new method for finding a fixed local-optimal policy for computing the customer lifetime value. The method is developed for a class of ergodic controllable finite Markov chains. We propose an approach based on a non-converging state-value function that fluctuates (increases and decreases) between states of the dynamic process. We prove that it is possible to represent that function in a recursive format using a one-step-ahead fixed-optimal policy. Then, we provide an analytical formula for the numerical realization of the fixed local-optimal strategy. We also present a second approach based on linear programming, to solve the same problem, that implement the c-variable method for making the problem computationally tractable. At the end, we show that these two approaches are related: after a finite number of iterations our proposed approach converges to same result as the linear programming method. We also present a non-traditional approach for ergodicity verification. The validity of the proposed methods is successfully demonstrated theoretically and, by simulated credit-card marketing experiments computing the customer lifetime value for both an optimization and a game theory approach. © 2014, Systems Engineering Society of China and Springer-Verlag Berlin Heidelberg.


Villalobos-Castaldi F.M.,Mexican Center for Research and Advanced Studies | Suaste-Gomez E.,Mexican Center for Research and Advanced Studies
Expert Systems with Applications | Year: 2013

A novel pupillary-based verification system is introduced, along with the early identity authentication results and analysis, based on the spatio-temporal features computed from the spontaneous papillary oscillations. The authors demonstrate that this biometric trait has the capability to provide enough discriminative information to authenticate the identity of a subject. A new methodology to compute the spatio-temporal biometric template recordings of the pupil area changes, in a video-oculography sequence under constant luminance level, is also introduced in this paper. According to the authors' knowledge, there is no evidence that other attempts were made, addressing this methodology to distinguish individuals based on the spatio-temporal representations, computed from the normal dilation-contraction behavior of the pupil. In this work, liveness will be detected by using the information obtained from the spontaneous pupillary oscillation mechanism. Preliminary experiments were conducted by using a particular own collected database, resulting in a (Equal Error Rate) in the order of 0.2338%. © 2013 Elsevier Ltd. All rights reserved.


Morales E.,Mexican Center for Research and Advanced Studies | Ramirez A.,Mexican Center for Research and Advanced Studies
IET Generation, Transmission and Distribution | Year: 2013

This study describes an enhanced hybrid method for calculating the periodic steady state of radial and weakly meshed distribution networks. The forward/backward sweeping technique has been taken here as basis to compute the network's equilibrium, accounting that non-linear elements and electronic devices are included. On one hand, a modified harmonic domain (MHD), based on the discrete Fourier transform (DFT), has been used to account for harmonics and interharmonics simultaneously, involving only matrix/vector operations. On the other hand, non-linear elements and electronic devices are handled in the time domain and included in the sweeping solution scheme by interfacing MHD and time domain through DFT operations. The proposed hybrid sweeping-based technique and a Newton-based method are compared here through a network example. ©The Institution of Engineering and Technology 2013.


Arellano Aguilar R.,Mexican Center for Research and Advanced Studies | Burciaga Diaz O.,Mexican Center for Research and Advanced Studies | Escalante Garcia J.I.,Mexican Center for Research and Advanced Studies
Construction and Building Materials | Year: 2010

This work investigated geopolymeric lightweight concretes based on binders composed of metakaolin with 0% and 25% fly ash, activated with 15.2% of Na2O using sodium silicate of modulus SiO2/Na2O = 1.2. Concretes of densities of 1200, 900 and 600 kg/m3 were obtained by aeration by adding aluminium powder, in some formulations lightweight aggregate of blast furnace slag was added at a ratio binder:aggregate 1:1; curing was carried out at 20 and 75 °C. The compressive and flexural strength development was monitored for up to 180 days. The strength diminished with the reduction of the density and high temperature curing accelerated strength development. The use of the slag had a positive effect on strength for 1200 kg/m3 concretes; reducing the amount of binder used. The thermal conductivity diminished from 1.65 to 0.47 W/mK for densities from 1800 to 600 kg/m3. The microstructures revealed dense cementitious matrices conformed of reaction products and unreacted metakaolin and fly ash. Energy dispersive spectroscopy and X-ray diffraction showed the formation of amorphous silicoaluminate reaction products. © 2009.


Ponsich A.,Autonomous University of Mexico City | Jaimes A.L.,Mexican Center for Research and Advanced Studies | Coello C.A.C.,Mexican Center for Research and Advanced Studies
IEEE Transactions on Evolutionary Computation | Year: 2013

The coinciding development of multiobjective evolutionary algorithms (MOEAs) and the emergence of complex problem formulation in the finance and economics areas has led to a mutual interest from both research communities. Since the 1990s, an increasing number of works have thus proposed the application of MOEAs to solve complex financial and economic problems, involving multiple objectives. This paper provides a survey on the state-of-the-art of research, reported in the specialized literature to date, related to this framework. The taxonomy chosen here makes a distinction between the (widely covered) portfolio optimization problem and the other applications in the field. In addition, potential paths for future research within this area are identified. © 1997-2012 IEEE.


Gomez W.,Mexican Center for Research and Advanced Studies | Pereira W.C.A.,Federal University of Rio de Janeiro | Infantosi A.F.C.,Federal University of Rio de Janeiro
IEEE Transactions on Medical Imaging | Year: 2012

In this paper, we investigated the behavior of 22 co-occurrence statistics combined to six gray-scale quantization levels to classify breast lesions on ultrasound (BUS) images. The database of 436 BUS images used in this investigation was formed by 217 carcinoma and 219 benign lesions images. The region delimited by a minimum bounding rectangle around the lesion was employed to calculate the gray-level co-occurrence matrix (GLCM). Next, 22 co-occurrence statistics were computed regarding six quantization levels (8, 16, 32, 64, 128, and 256), four orientations (0° , 45° , 90° , and 135° ), and ten distances (1, 2,..,10 pixels). Also, to reduce feature space dimensionality, texture descriptors of the same distance were averaged over all orientations, which is a common practice in the literature. Thereafter, the feature space was ranked using mutual information technique with minimal-redundancy-maximal- relevance (mRMR) criterion. Fisher linear discriminant analysis (FLDA) was applied to assess the discrimination power of texture features, by adding the first m-ranked features to the classification procedure iteratively until all of them were considered. The area under ROC curve (AUC) was used as figure of merit to measure the performance of the classifier. It was observed that averaging texture descriptors of a same distance impacts negatively the classification performance, since the best AUC of 0.81 was achieved with 32 gray levels and 109 features. On the other hand, regarding the single texture features (i.e., without averaging procedure), the quantization level does not impact the discrimination power, since AUC=0.87 was obtained for the six quantization levels. Moreover, the number of features was reduced (between 17 and 24 features). The texture descriptors that contributed notably to distinguish breast lesions were contrast and correlation computed from GLCMs with orientation of 90° and distance more than five pixels. © 1982-2012 IEEE.

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