Poblado C-11 José María Morelos y Pavón, Mexico
Poblado C-11 José María Morelos y Pavón, Mexico
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Perez-Rodriguez R.,CIATEC | Jons S.,University of Guanajuato | Hernandez-Aguirre A.,CIMAT | Alberto-Ochoa C.,UACJ
International Journal of Advanced Manufacturing Technology | Year: 2014

The flexible jobshop scheduling problem permits the operation of each job to be processed by more than one machine. The idea is to assign the processing sequence of operations on the machines and the assignment of operations on machines such that the systemobjectives can be optimized. The assignment mentioned is a difficult task to implement on real manufacturing environments because there are many assumptions to satisfy, especially when the amount of work is not constant or sufficient to keep the manufacturing process busy for a long time, causing intermittent idle times. An estimation of distribution algorithm-based approach coupled with a simulationmodel is developed to solve the problemand implement the solution. Using the proposed approach, the shop performance can be noticeably improved when different machines are assigned to different schedules. © Springer-Verlag London 2014.

Petean J.,CIMAT | Petean J.,University of Buenos Aires | Ruiz J.M.,IMPA
Differential Geometry and its Application | Year: 2013

We compare the isoperimetric profiles of S2×R3 and of S3×R2 with that of a round 5-sphere (of appropriate radius). Then we use this comparison to obtain lower bounds for the Yamabe constants of S2×R3 and S3×R2. Explicitly we show that Y(S3×R2,[g0 3+dx 2])>(3/4)Y(S5) and Y(S2×R3,[g0 2+dx 2])>0.63Y(S5). We also obtain explicit lower bounds in higher dimensions and for products of Euclidean space with a closed manifold of positive Ricci curvature. The techniques are a more general version of those used by the same authors in Petean and Ruiz (2011) [15] and the results are a complement to the work developed by B. Ammann, M. Dahl and E. Humbert to obtain explicit gap theorems for the Yamabe invariants in low dimensions. © 2013 Elsevier B.V.

Otoba N.,Keio University | Petean J.,CIMAT
Differential Geometry and its Application | Year: 2016

Let G/. H be a Riemannian homogeneous space. For an orthogonal representation φ of H on the Euclidean space Rk+1, there corresponds the vector bundle E=G×φRk+1→G/H with fiberwise inner product. Provided that φ is the direct sum of at most two representations which are either trivial or irreducible, we construct metrics of constant scalar curvature on the unit sphere bundle UE of E. When G/. H is the round sphere, we study the number of constant scalar curvature metrics in the conformal classes of these metrics. © 2016 Elsevier B.V..

Iturriaga R.,CIMAT | Maderna E.,University of the Republic of Uruguay
Celestial Mechanics and Dynamical Astronomy | Year: 2015

We prove that, for generic (open and dense) values of the masses, the Newtonian potential function of the collinear N-body problem has [InlineEquation not available: see fulltext.] critical values when restricted to a fixed inertia level. In particular, we prove that for generic values of the masses, there is only one global minimal Moulton configuration. © 2015, Springer Science+Business Media Dordrecht.

Esteban P.C.A.,University of Valladolid | Ortega J.,CIMAT
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2012

: In this work we look at the spectral evolution of waves from the point of view of the total variation (TV) distance. There are several methods for determining changes in the variance of a random process, which correspond to changes in the total energy of the waves. We look instead at changes in the distribution of the energy as given by the energy spectra, after they have been normalized to correspond to a process with unit variance, using the total variation distance. This corresponds to looking at changes in the distribution of energy instead of changes of the total energy present. The TV distance has been successfully used for the comparison of random samples and probability distributions and measures the difference between two probability distributions determining how much one of them has to be modified to coincide with the other. We consider several sets of waves measured at fixed locations over periods of several hours or days and calculate the wave spectrum for periods of 30 minutes. After all the spectra have been normalized the TV distance between all spectra is calculated and used to determine change points in the sequence of normalized energy spectra. We show examples in which although there is considerable change in the significant wave height for the different time intervals, the energy distribution remains essentially unchanged. The method could be used to determine periods of stationarity for sea waves. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).

Solis F.J.,CIMAT | Delgadillo S.E.,Autonomous University of Aguascalientes
Mathematical and Computer Modelling | Year: 2013

Discrete mathematical models are proposed to study the dynamics of interacting cells of an organism that is affected by an aggressive heterogeneous tumor. The models include the application of a chemotherapy treatment with a gradual effect. Another factor included in the models is the competence among the different tumor cells. An effective treatment index is introduced in order to analyze the evolution of the tumor and to compare different treatments. © 2011 Elsevier Ltd.

Arizmendi O.,CIMAT | Hasebe T.,Hokkaido University
Complex Analysis and Operator Theory | Year: 2016

We realize the Belinschi–Nica semigroup of homomorphisms as a free multiplicative subordination. This realization allows to define more general semigroups of homomorphisms with respect to free multiplicative convolution. For these semigroups we show that a differential equation holds, generalizing the complex Burgers equation. We give examples of free multiplicative subordination and find a relation to the Markov–Krein transform, Boolean stable laws and monotone stable laws. A similar idea works for additive subordination, and in particular we study the free additive subordination associated to the Cauchy distribution and show that it is a homomorphism with respect to monotone, Boolean and free additive convolutions. © 2015, Springer Basel.

Jerez S.,CIMAT | Lara A.,CIMAT
Mathematical and Computer Modelling | Year: 2011

In this work, a high resolution nonstandard finite-difference time-domain method for the transverse magnetic (TM) mode of 2D-Maxwell's equations is derived. Stability and convergence analysis and numerical studies are presented for the proposed method. The accuracy of this numerical scheme is validated by simulating a light scattering cross-section by a perfectly-conducting circular cylinder. © 2010 Elsevier Ltd.

Journal of Geometry and Physics | Year: 2012

We let (Mm, g) be a closed smooth Riemannian manifold with positive scalar curvature Sg, and prove that the Yamabe constant of (M×Rn, g+gE) (n, m≥2) is achieved by a metric in the conformal class of (g+gE), where gE is the Euclidean metric. We do this by showing that the Yamabe functional of (M×Rn, g+gE) is improved under Steiner symmetrization with respect to M, and so, the dependence on Rn of the Yamabe minimizer of (M×Rn, g+gE) is radial. © 2011 Elsevier B.V..

Solis F.J.,CIMAT | Gonzalez L.M.,CIMAT
International Journal of Computer Mathematics | Year: 2014

Worldwide, cervical cancer is the second most common cancer in women, after breast cancer. The prevalence of this malignant disease is estimated at 1.4 million cases worldwide, causing about 290,000 deaths and 500,000 new cases per year, of which 80% correspond to women living in developing countries. In this work we propose a family of ordered models for basal cells of the cervix corresponding to different stages ranging from normal cells to the formation of precancerous lesions. We analyse the first member of the family analytically and for the second member we developed a non-standard numerical method in order to extract some biological information. © 2013 © 2013 Taylor & Francis.

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