Technological University of Mixteca
Oaxaca, Mexico
Time filter
Source Type

Moya-Cessa H.,National Institute of Astrophysics, Optics and Electronics | Soto-Eguibar F.,National Institute of Astrophysics, Optics and Electronics | Vargas-Martinez J.M.,National Institute of Astrophysics, Optics and Electronics | Juarez-Amaro R.,Technological University of Mixteca | Zuniga-Segundo A.,Escuela Superior de Fisica y Matematicas Edificio 9
Physics Reports | Year: 2012

Trapped ions are considered one of the best candidates to perform quantum information processing. By interacting them with laser beams they are, somehow, easy to manipulate, which makes them an excellent choice for the production of nonclassical states of their vibrational motion, the reconstruction of quasiprobability distribution functions, the production of quantum gates, etc. However, most of these effects have been produced in the so-called low intensity regime, this is, when the Rabi frequency (laser intensity) is much smaller than the trap frequency. Because of the possibility to produce faster quantum gates in other regimes it is of importance to study this system in a more complete manner, which is the motivation for this contribution. We start by studying the way ions are trapped in Paul traps and review the basic mechanisms of trapping. Then we show how the problem may be completely solved for trapping states; i.e., we find (exact) eigenstates of the full Hamiltonian. We show how, in the low intensity regime, Jaynes-Cummings and anti-Jaynes-Cummings interactions may be obtained, without using the rotating wave approximation and analyze the medium and high intensity regimes where dispersive Hamiltonians are produced. The traditional approach (low intensity regime) is also studied and used for the generation of non-classical states of the vibrational wavefunction. In particular, we show how to add and subtract vibrational quanta to an initial state, how to produce specific superpositions of number states and how to generate NOON states for the two-dimensional vibration of the ion. It is also shown how squeezing may be measured. The time dependent problem is studied by using Lewis-Ermakov methods. We give a solution to the problem when the time dependence of the trap is considered and also analyze a specific (artificial) time dependence that produces squeezing of the initial vibrational wave function. A way to mimic the ion-laser interaction via classical optics is also introduced. © 2012 Elsevier B.V.

Caballero-Morales S.-O.,Technological University of Mixteca
Mathematical Problems in Engineering | Year: 2014

Shewhart or control charts are important Statistical Process Control (SPC) techniques used for prompt detection of failures in a manufacturing process and minimization of production costs which are modelled with nonlinear functions (cost functions). Heuristic methods have been used to find the chart's parameters integrated within the cost function that best comply with economic and statistical restrictions. However heuristic estimation is highly dependent on the size of the search space, the set of initial solutions, and the exploration operators. In this paper the 3D analysis of the cost function is presented to more accurately identify the search space associated with each parameter of X ¯ control charts and to improve estimation. The parameters estimated with this approach were more accurate than those estimated with Hooke and Jeeves (HJ) and Genetic Algorithms (GAs) under different failure distributions. The results presented in this work can be used as a benchmark to evaluate and improve the performance of other heuristic methods. © 2014 Santiago-Omar Caballero-Morales.

Caballero-Morales S.-O.,Technological University of Mixteca
The Scientific World Journal | Year: 2013

An approach for the recognition of emotions in speech is presented. The target language is Mexican Spanish, and for this purpose a speech database was created. The approach consists in the phoneme acoustic modelling of emotion-specific vowels. For this, a standard phoneme-based Automatic Speech Recognition (ASR) system was built with Hidden Markov Models (HMMs), where different phoneme HMMs were built for the consonants and emotion-specific vowels associated with four emotional states (anger, happiness, neutral, sadness). Then, estimation of the emotional state from a spoken sentence is performed by counting the number of emotion-specific vowels found in the ASR's output for the sentence. With this approach, accuracy of 87-100% was achieved for the recognition of emotional state of Mexican Spanish speech. © 2013 Santiago-Omar Caballero-Morales.

Caballero Morales S.O.,Technological University of Mixteca
PLoS ONE | Year: 2013

The application of Preventive Maintenance (PM) and Statistical Process Control (SPC) are important practices to achieve high product quality, small frequency of failures, and cost reduction in a production process. However there are some points that have not been explored in depth about its joint application. First, most SPC is performed with the X-bar control chart which does not fully consider the variability of the production process. Second, many studies of design of control charts consider just the economic aspect while statistical restrictions must be considered to achieve charts with low probabilities of false detection of failures. Third, the effect of PM on processes with different failure probability distributions has not been studied. Hence, this paper covers these points, presenting the Economic Statistical Design (ESD) of joint X-bar-S control charts with a cost model that integrates PM with general failure distribution. Experiments showed statistically significant reductions in costs when PM is performed on processes with high failure rates and reductions in the sampling frequency of units for testing under SPC. © 2013 Caballero Morales.

Juarez-Abad J.A.,Technological University of Mixteca | Linares-Flores J.,Technological University of Mixteca | Guzman-Ramirez E.,Technological University of Mixteca | Sira-Ramirez H.,CINVESTAV
IEEE Transactions on Industrial Informatics | Year: 2014

This paper presents a robust linear generalized proportional integral (GPI) control scheme for the output reference trajectory tracking task on a multilevel single-phase 'buck' inverter. The scheme is shown to be robust with respect to arbitrary time-varying load current demands, acting as perturbation inputs to the inverter, and to significant converter parameter variations. The discrete time version of the control scheme is implemented on a field-programmable gate array hardware. Several laboratory robustness tests are performed on the controlled inverter with excellent results. © 2005-2012 IEEE.

Caballero-Morales S.-O.,Technological University of Mixteca | Trujillo-Romero F.,Technological University of Mixteca
Expert Systems with Applications | Year: 2014

Dysarthria is a motor speech disorder caused by neurological injury of the motor component of the motor-speech system. Because it affects respiration, phonation, and articulation, it leads to different types of impairments in intelligibility, audibility, and efficiency of vocal communication. Speech Assistive Technology (SAT) has been developed with different approaches for dysarthric speech and in this paper we focus on the approach that is based on modeling of pronunciation patterns. We present an approach that integrates multiple pronunciation patterns for enhancement of dysarthric speech recognition. This integration is performed by weighting the responses of an Automatic Speech Recognition (ASR) system when different language model restrictions are set. The weight for each response is estimated by a Genetic Algorithm (GA) that also optimizes the structure of the implementation technique (Metamodels) which is based on discrete Hidden Markov Models (HMMs). The GA makes use of dynamic uniform mutation/crossover to further diversify the candidate sets of weights and structures to improve the performance of the Metamodels. To test the approach with a larger vocabulary than in previous works, we orthographically and phonetically labeled extended acoustic resources from the Nemours database of dysarthric speech. ASR tests on these resources with the proposed approach showed recognition accuracies over those obtained with standard Metamodels and a well used speaker adaptation technique. These results were statistically significant. © 2013 Elsevier Ltd. All rights reserved.

Castillo-Torres J.,Technological University of Mixteca
Optics Communications | Year: 2013

Direct and indirect transition energies near the optical absorption band edge for lithium niobate crystals doped with zinc at several concentrations have been obtained. These energy values are larger than those corresponding to undoped lithium niobate even when zinc concentration is above the optical damage threshold value. For any zinc concentration, 4.0 eV was measured for direct transition energy and a range of 3.8-3.9 eV was determined for indirect transition energy; whereas 3.8 and 3.6 eV were obtained, respectively, for the corresponding values of pure lithium niobate. In addition, phonon and Urbach energies were also calculated where these values are lesser than those of pure lithium niobate. Both behaviors remain unchanged regardless of whether the zinc concentration is above or below the optical damage critical value. Substitution of only lithium vacancies and antisite defects by zinc atoms for any concentration of doping may explain the results. © 2012 Elsevier B.V. All rights reserved.

The Discrete Compactness is a factor that describes the shape of an object. One of its main strengths lies in its low sensitivity to variations, due to noise or capture defects, in the shape of an object. Then, we use Discrete Compactness in order to propose a new approach for non-supervised classification of tissue in Computed Tomography brain slices. The proposal is sustained on the use of One-Dimensional Kohonen Self-Organizing Maps. The images are segmented is such way tissue is characterized according to its geometrical and topological neighborhood. Our main contribution is based in the use of a new similarity metric which makes use of Discrete Compactness. We will present arguments to sustain the fact, from an experimental point of view, that the use of Discrete Compactness as a similarity metric for segmentation purposes impacts additional processes such as the classification of segmented images. The impact will be boarded in two ways: a) respect to the differences existing between segmented images in a same class, and b) respect to the way a representative relates with the members of its class. In both cases, we will be assisted by some simple error functions.

Trujillo-Romero F.,Technological University of Mixteca
International Journal of Bio-Inspired Computation | Year: 2013

This paper discusses the generation of neural networks that are obtained from the evolution of individual's population in a genetic algorithm. For achieving this, the population of individuals for the genetic algorithm is formed of structural elements which constitute the neural networks. These elements include the number of layers, neurons per layer, transfer functions and the connections between neurons in the network, among others. These individuals as can be seen a structure which has the ability to evolve rather than a standard genotype. Furthermore, the size of the individuals is not defined and depends mainly on the neural network which in turn depends on the problem to be solved. This structure considered as an evolutionary entity, is able to evolve until convergence towards a suitable structure is achieved. The fitness function is specified with the features of the problem to be solved by the neural network. This algorithm has been tested successfully in solving classification problems, as in the case of alpha-numerical character recognition, and has been compared against a neural network obtained by conventional means. Better results were obtained with the neural network generated by using genetic programming of this type of evolutionary entities. Copyright © 2013 Inderscience Enterprises Ltd.

Caballero-Morales S.-O.,Technological University of Mixteca
CONIELECOMP 2014 - 24th International Conference on Electronics, Communications and Computers | Year: 2014

Service Robotics (SR) is one of the main areas of research for the development of assistive and supportive technologies for humans. Nowadays there are many robotic platforms used for this purpose. Among them, the Bioloid is one of the most widely used platforms due to the flexibility of its structure (e.g., different types of robots can be built). Particularly, the Bioloid configured with humanoid structure is suitable for assistive tasks. Robot-assisted writting is among the most challenging tasks to implement given its complexity and required fine control. In this paper, the development of a set of motion models for the humanoid Bioloid for each character in the Spanish alphabet is presented. For the motion models, initially the ability of the Bioloid's servomechanisms to achieve smooth and straight trajectories was evaluated under different conditions of speed rate, joint softness, and inertial force. Then, three approaches were considered to define the straight trajectories used to draw each alphabet character: continuous, segment-based, and point-based. In practice it was found that medium speed rate and inertial force with high softness led to straight trajectories. Also, the point-based approach performed better (generated highly defined alphabet characters) than the segment-based approach, and both performed better than the continuous approach. The resulting models can be used to evaluate the performance of trajectory planning techniques or continuous transcription of acoustic information. © 2014 IEEE.

Loading Technological University of Mixteca collaborators
Loading Technological University of Mixteca collaborators