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Singular extended skew-elliptical distributions
Jose A. Diaz-Garcia,Graciela Gonzalez-Farias 한국통계학회 2008 Journal of the Korean Statistical Society Vol.37 No.4
Singular vector and matrix extended skew-elliptical distributions are studied in this work. Based on the vectorial case, two alternatives for singular matrix variate extended skew-elliptical distribution are also proposed. In addition, the distributions of a general linear transformation for extended skew-elliptical vectors and matrices are derived along with the corresponding density functions. These results are applied in the distribution of the residuals for a general linear model with extended skew-elliptical errors.
Benitez-Garcia, Sandy E.,Kanda, Isao,Okazaki, Yukiyo,Wakamatsu, Shinji,Basaldud, Roberto,Horikoshi, Nobuji,Ortinez, Jose A.,Ramos-Benitez, Victor R.,Cardenas, Beatriz Korean Society for Atmospheric Environment 2015 Asian Journal of Atmospheric Environment (AJAE) Vol.9 No.2
In the Mexico City Metropolitan Area (MCMA), ozone ($O_3$) concentration is still higher than in other urban areas in developed countries. In order to reveal the current state of photochemical air pollution and to provide data for validation of chemical transport models, vertical profiles of meteorological parameters and ozone concentrations were measured by ozonesonde in two field campaigns: the first one, during the change of season from wet to dry-cold (November 2011) and the second during the dry-warm season (March 2012). Unlike previous similar field campaigns, ozonesonde was launched twice daily. The observation data were used to analyze the production and distribution of ozone in the convective boundary layer. The observation days covered a wide range of meteorological conditions, and various profiles were obtained. The evolution of the mixing layer (ML) height was analyzed, revealing that ML evolution was faster during daytime in March 2012 than in November 2011. On a day in November 2011, the early-morning strong wind and the resulting vertical mixing was observed to have brought the high-ozone-concentration air-mass to the ground and caused relatively high surface ozone concentration in the morning. The amount of produced ozone in the MCMA was estimated by taking the difference between the two profiles on each day. In addition to the well-known positive correlation between daily maximum temperature and ozone production, effect of the ML height and wind stagnation was identified for a day in March 2012 when the maximum ground-level ozone concentration was observed during the two field campaigns. The relatively low ventilation coefficient in the morning and the relatively high value in the afternoon on this day implied efficient accumulation of the $O_3$ precursors and rapid production of $O_3$ in the ML.
Hernandez-Flores, Mario A.,Galeano-Torres, Rodrigo,Garcia-Castillo, Miguel A.,Landeros-Ayala, Salvador,Matias-Maruri, Jose M. Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.4
This work proposes suitable network configurations for single frequency networks (SFNs) with ATSC 1.0 based on network coverage calculations and the laboratory multipath handling performance of commercial receivers. SFNs are widely used for delivering terrestrial digital television services because of their efficient use of the spectrum. In Mexico the analogue television transmissions switch-off occurred on 31 December 2016. Thus it is expected the adopted ATSC 1.0 system will be in force for the next several years despite the recent standardization of the ATSC 3.0 system. As ATSC 1.0 uses 8-VSB modulation the multipath handling capability of receivers is critical for the design of SFNs. The presented network planning results help develop technical normativity for implementing SFNs in Mexico and other countries that use ATSC 1.0. SFNs with transmitter separation up to 130 km are fully covered for outdoor reception mainly due to the directivity of the receiving antenna. Moreover for indoor reception at least 70% of an SFN coverage area can be achieved with a transmitter separation of up to 60 km depending on the radiated power and the transmitter antenna height.
Optimal Dispatch Model for Demand Response Aggregators
Victor J. Gutierrez-Martinez,Enrique A. Zamora-Cardenas,Alejandro Pizano-Martinez,Jose M. Lozano-Garcia,Miguel A. Gomez-Martinez 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1
This paper proposes a new three-phase optimal dispatch model for multiple Demand Response (DR) aggregators. By means of the unbalanced distribution system modeling, DR involvement of single- and three-phase consumers is considered avoiding aggravating the asymmetric balancing between phases, as opposed to traditional positive-sequence DR approaches. Furthermore, this proposal can consider several DR service providers by means of the explicit inclusion of their characteristics, in the form of cost functions and capacity, in an optimal dispatch model for DR support at the distribution system level. Hence, this proposal helps to eliminate any possible uncertainty about the provision of DR services by improving the traditional hierarchical scheme adopted based on prices issued by the Independent System Operator (ISO). The model is implemented and solved combining the two state-of-the-art computational tools, Matlab® and OpenDSS. The former is used to solve the optimization problem, whereas the latter is used to perform numerical simulations of three-phase unbalanced power flow; both tools allow a straightforward model implementation resulting in a tool easily modified and updated. The effectiveness of the proposed approach is numerically demonstrated using the IEEE 13- and 123-node test feeders, in which undesirable operating scenarios are corrected by the implementation of the optimal dispatch of DR resources in very short computational times. Based on the results, it is shown how the ISO is capable to request DR considering several aggregators competing at the distribution system level. Finally, the loss reduction has been included in the objective function, showing that the proposal optimally dispatches the DR aggregators to conveniently minimize the ISO’s operational costs.
Adaptive Super Twisting Control of a Dual-rotor VTOL Flight System Under Model Uncertainties
Jorge M. Arizaga,Jose. R. Noriega,L. A. Garcia-Delgado,Herman Castaneda 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.6
This paper addresses an adaptive super twisting control for a dual-rotor flight system subject to uncertainties. The system can perform vertical take-off and landing, roll and yaw movements. The dynamical model is described under the Euler-Lagrange approach, where a characterization of the thrust and the torque of the rotors is included. However, uncertainties such as friction and unmodeled dynamics remain. To overcome these problems, a class of adaptive sliding mode control is designed, which is robust to bounded uncertainties and external perturbations, offers reduced chattering, and not overestimate the control gain. Furthermore, the closed-loop stability is analyzed. Finally, simulation and experimental validation, and a comparison versus other standard control approaches illustrate the feasibility and usefulness of the proposed controller.
Sandy E. Benitez-Garcia,Isao Kanda,Yukiyo Okazaki,Shinji Wakamatsu,Roberto Basaldud,Nobuji Horikoshi,Jose A. Ortinez,Victor R. Ramos-Benitez,Beatriz Cardenas 한국대기환경학회 2015 Asian Journal of Atmospheric Environment (AJAE) Vol.9 No.2
In the Mexico City Metropolitan Area (MCMA), ozone (O3) concentration is still higher than in other urban areas in developed countries. In order to reveal the current state of photochemical air pollution and to provide data for validation of chemical transport models, vertical profiles of meteorological parameters and ozone concentrations were measured by ozonesonde in two field campaigns: the first one, during the change of season from wet to dry-cold (November 2011) and the second during the drywarm season (March 2012). Unlike previous similar field campaigns, ozonesonde was launched twice daily. The observation data were used to analyze the production and distribution of ozone in the convective boundary layer. The observation days covered a wide range of meteorological conditions, and various profiles were obtained. The evolution of the mixing layer (ML) height was analyzed, revealing that ML evolution was faster during daytime in March 2012 than in November 2011. On a day in November 2011, the early-morning strong wind and the resulting vertical mixing was observed to have brought the high-ozone-concentration air-mass to the ground and caused relatively high surface ozone concentration in the morning. The amount of produced ozone in the MCMA was estimated by taking the difference between the two profiles on each day. In addition to the well-known positive correlation between daily maximum temperature and ozone production, effect of the ML height and wind stagnation was identified for a day in March 2012 when the maximum ground-level ozone concentration was observed during the two field campaigns. The relatively low ventilation coefficient in the morning and the relatively high value in the afternoon on this day implied efficient accumulation of the O3 precursors and rapid production of O3 in the ML.
Alvarez-Carrizal, Ruth P.,Rodriguez-Garcia, Jose A.,Cortes-Hernandez, Dora A.,Esparza-Vazquez, Sergio J.,Rocha-Rangel, Enrique Techno-Press 2021 Advances in materials research Vol.10 No.4
This research shows the development of a composite material with an alumina matrix reinforced with different percentages of titanium (0.0%, 0.5%, 1%, 2% y 3%) with the intention of analyzing their mechanical and biocompatible properties for its possible application as a biomaterial. Alumina was synthesized using the reaction bonding aluminum oxide (RBAO) methodology. The powders resulting from the milling process had a size distribution ranging from nanometers to 2 microns. By means of X-ray diffraction and differential thermal analysis, it was determined that aluminum oxidizes in both solid and liquid states. It was also found that the alumina formation reaction is complete at 900℃. Using scanning electron microscopy, it was determined that the microstructure has fine grain sizes and homogeneous morphology. Likewise, the elastic modulus and fracture toughness of the composites obtained were determined, results indicate that these properties are higher than the properties of cortical bone. In addition, bioactivity was promoted using the biomimetic method. The results obtained demonstrate that the resulting composite can be used as a biomaterial.
Alejandra Mina Rosales,Elena Aznar,Carmen Coll,Ruben A. Garcia Mendoza,A. Lorena Urbano Bojorge,Nazario Felix Gonzalez,Ramon Martinez-Manez,Francisco del Pozo Guerrero,Jose Javier Serrano Olmedo 한국자기학회 2016 Journal of Magnetics Vol.21 No.3
Magnetic hyperthermia mediated by superparamagnetic particles is mainly based in sinusoidal waveforms as excitation signals. Temperature changes are conventionally explained by rotation of the particles in the surrounding medium. This is a hypothesis quite questionable since habitual experimental setups only produce changes in the magnetic module, not in the field lines trajectories. Theoretical results were tested by changing the waveform of the exciting signal in order to compare non-sinusoidal signals against sinusoidal signals. Experiments were done at different frequencies: 200 ㎑, 400 ㎑, 600 ㎑, 800 ㎑ and 1 ㎒. Superparamagnetic Iron Oxide samples (SPION), made of magnetite (Fe3O4) and suspended in water (100 ㎎/ml), were used. Magnetic field strength varies from 0.1 ± 0.015 KA/m to 0.6 ± 0.015 KA/m. In this study was observed that the power loss depends on the applied frequency: for 1 to 2.5 RMS current the responses for each signal are part of the higher section of the exponential function, and for 3.5 to 8 RMS current the response is clearly the decrement exponential function’s tale (under 1 × 10³ LER/gr).