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JUAN ANDRES PEREZ CELIS (2016)
The use of Static Random-Access Memory (SRAM)-based Field Programmable Gate
Arrays (FPGAs) in space systems is gaining a growing interest. The high-computational
power, the ability to reconfigure and the flexibility of FPGAs at low power make them
suitable devices for space applications. Nevertheless, FPGAs are susceptible to Single
Event Upsets which may cause an operational failure, leading to a decrease of the
reliability. Fault Mitigation Techniques (FMT) are used to increase the reliability,
making the architecture suitable for operating in the space. However, estimating the
reliability of a FPGA design can be challenging. The preferred method consists of
placing the FPGA under a high-energy particle beam and performing the test iteratively
to estimate the reliability. The iterative process makes radiation testing prohibitive for
many space applications, as the monetary cost and time spent for radiation testing is
This thesis proposes a method for determining the reliability of an FPGA
architecture with FMTs applied based on the failure rate of an unmitigated design.
The method uses Markov chains to model the architecture and estimate the reliability.
An unmitigated design and a mitigated design were developed and placed under a
neutron beam to estimate the reliability. The mitigated design decreases the sensible
area, i.e. increases the reliability, by a factor of 20:18. The mitigated design is a
triplication of the mitigated design with additional voters placed throughout the
architecture. Two models resembling the behavior of the mitigated design with a
Medium Grain Triple Modular Redundancy (MGTMR) are proposed. The difference
of the models lies in the addition of shared-resources modules. The results of the
models show that the estimation of reliability is close to that obtained through
YURIY KOTSARENKO (2013)
Two novel color spaces are described for color specification and image processing using cylindrical variants of YIQ color space. The classical color spaces HSL and HSV do not take human perception into account and are perceptually inaccurate. Perceptually uniform color spaces such as CIELAB and CIELUV are computationally expensive for real-time interactive applications and are difficult to implement. Proposed alternatives in this work provide a reasonable balance between perceptual uniformity, performance and calculation simplicity. They model colors more accurately are fast to compute. Experimental results are provided, where the classical color spaces are compared to the proposed ones in terms of perceptual uniformity, color richness and performance, including numerous benchmarks on multi-core processors and mobile systems such as ultraportable computers and tablets such as iPad. The results provide evidence that the proposed color spaces are better alternatives for computer industry where classical color spaces are currently being used.
En este trabajo dos nuevos espacios de color se describen para especificación de colores y procesamiento de imágenes utilizando la forma cilíndrica del espacio de color YIQ. Los espacios de colores clásicos tales como HSL y HSV no toman en cuenta la visión humana y son perceptualmente inexactos. Los espacios de colores perceptualmente uniformes como CIELAB y CIELUV son muy costosos computacionalmente para aplicaciones interactivas de tiempo real y son difíciles de implementar. Las alternativas propuestas, por otro lado, tienen un balance entre uniformidad perceptual, desempeño y simplicidad de cálculo. Estos espacios modelan colores de forma más exacta y son rápidos de calcular. Los resultados experimentales en este trabajo comparan espacios de colores clásicos con los propuestos en términos de uniformidad, riqueza de colores y desempeño, incluyendo numerosas pruebas de rapidez en procesadores de varios núcleos y sistemas móviles tales como ultra portátiles y los tablets tipo iPad. Los resultados evidencian que los espacios de colores propuestos son mejores alternativas para la industria de computación donde actualmente se utilicen los espacios de colores clásicos.
Human efforts to produce ever-greater amounts of food leave their mark on the environment. Persistent use of conventional farming practices based on extensive tillage, especially when combined with removal or in situ burning of crop residue, has magnified soil erosion losses and the soil resource base has been steadily degraded. It has been estimated that human activity is responsible for the loss of 26 billion tons of topsoil per year, which is 2.6 times the natural rate of soil degradation. Erosion has been estimated to cause USD $44 billion a year in damage to farmland, waterways, infrastructure, and health. Crop yields in the US would drop 8% per year if farmers failed to replace lost nutrients and water (Pimentel et al., 1995). Another direct consequence of farmers' persistent use of traditional production practices is rapidly increasing production costs; the costs of inputs such as improved varieties and fertilizers continue to increase and farmers make inefficient use of them.
"Switched systems are capable of generating chaotic multi-scroll behavior in by means of a control signal. This signal regulates an equilibrium position of the system and is defined according to the number of scrolls that is displayed by the attractor. Thus, if two systems are controlled by different signals, they exhibit a different number of scrolls. Multistability can be created by a pair of unidirectionally coupled unstable dissipative switched linear systems. A theoretical study of this phenomenon is performed with the jerky equations. Generalized synchronization is observed in numerical simulations of the master-salve system with different control signals. The proposed configuration preserves the number of scrolls and can possess an arbitrary large number of coexisting chaotic multi-scroll attractors."
"In this paper, we present the preservation of a two-wing Lorenz-like attractor when in the Lorenz system a feedback control is applied, making two of its equilibria a sink. The forced system is capable of generating bistability and the trajectory settles down at one stable equilibrium point depending on the initial condition when the forced signal is zero. Due to a variation in the coupling strength of the control signal the symmetric equilibria of the Lorenz system move causing the basins of attraction to be the dynamic bounded regions that change accordingly. Thus, the preservation of a two-wing Lorenz-like attractor is possible using a switched control law between these dynamic basins of attraction. The forced switched systems also preserve multistability regarding the coupling strength and present multivalued synchronization according to the basin of attraction in which they were initialized. Bifurcations of the controlled system are used to exemplify the different basins generated by the forcing. An illustrative example is given to demonstrate the approach proposed."
En este artículo se presenta un análisis de los sistemas nacionales de innovación de México, España y Estados Unidos de América, empleando la metodología de análisis de entorno y de sistemas nacionales de innovación de la Organización para la Cooperación y el Desarrollo Económico a efecto de estudiar las diferencias y similitudes de los tres países e identificar sus fortalezas y debilidades. El propósito es identificar los distintos niveles de maduración de los sistemas nacionales de innovación de países con diferentes niveles de desarrollo económico, que puedan servir de experiencia al caso mexicano para corregir o impulsar las actuales políticas públicas de innovación. Un sistema nacional de innovación articulado, equilibrado y con empresas con capacidad de absorción tecnológica promueve el crecimiento económico de un país, aunque es necesario un enfoque de inclusión social para reflejar sus resultados en desarrollo
This paper presents an analysis of the national innovation systems of Mexico, Spain and the United States, using the Organization for Economic Cooperation and Development’s methodology on this subject, in order to study the differences and similarities of the three countries and to identify their strengths and weaknesses. The purpose is to recognize the different maturation levels of the national innovation systems of countries with different levels of economic development, that can be used as experience for the Mexican case to correct or promote current public innovation policies and clarify their path in this area. An articulated, balanced national innovation system, with firms which possess a high technological absorption capacity, can promote the eco-nomic and social growth of a country
"We present the design of an autonomous time-delay Boolean network realized with readily available electronic components. Through simulations and experiments that account for the detailed nonlinear response of each circuit element, we demonstrate that a network with five Boolean nodes displays complex behavior. Furthermore, we show that the dynamics of two identical networks display near-instantaneous synchronization to a periodic state when forced by a common periodic Boolean signal. A theoretical analysis of the network reveals the conditions under which complex behavior is expected in an individual network and the occurrence of synchronization in the forced networks. This research will enable future experiments on autonomous time-delay networks using readily available electronic components with dynamics on a slow enough time-scale so that inexpensive data collection systems can faithfully record the dynamics. "
The use of satellite data in combination with ground-based measurements can provide valuable information about atmospheric chemistry and air quality. In this study, ground-based Differential Optical Absorption Spectroscopy (DOAS) measurements of nitrogen dioxide (NO2) conducted in central Mexico are compared with the space-borne Ozone Monitoring Instrument (OMI) dataset of 2006-2011. Ground-based measurements exhibited large day-to-day variations and were on average three times higher than the space-borne derived average over the observation site. This difference is attributed to strong horizontal inhomogeneity of the lower layer of the measured NO2 columns, sampled over a large footprint from the satellite instrument. Also, a reduced sensitivity of the satellite observation near the surface, where the largest concentrations are expected, could be responsible for this large discrepancy. From the analyzed OMI dataset, distribution maps of NO2 above central Mexico were reconstructed, allowing to identify three main areas with increased NO2 column densities: The dominating metropolitan area of Mexico City, the heavily industrialized region of Tula to the north and the Cuernavaca valley to the south. In this analysis, seasonal variability of NO2 columns over central Mexico was detected, finding higher NO2 columns during the dry and cold season, followed by the dry and warm period, and finally the lowest NO2 columns were found during the rainy season. Pollution transport of this gas from Tula into Mexico City, as well as towards the Cuernavaca valley, is evident from this dataset.
RAFAEL HERNANDEZ ESPINOSA (2017)
The article starts out by conceiving shopping malls as one of the main scenes of urban life. That is, spaces for visibility as well as anonymity, despite their consumer vocation. This was the basis of research in microsocial interactions in two Mexico City malls. Data was acquired by the ethnographic method, combining direct observations with semi-structured interviews and photographic records. The discussion suggests that the architectural and advertising space planned fosters complex urban and commercial dynamics which are complemented with the practices of its users. The conclusion appeals to the importance of sensory experiences that offer a space not only in terms of its objects, but also the perceptive and significant processes triggered in the interactions with it and with the others.
Se parte de concebir los centros comerciales como escenarios protagónicos en la vida urbana, esto es, espacios de visibilidades a la vez que de anonimato, no obstante su vocación de consumo. Con base en ello, se indagan las interacciones microsociales en dos escenarios de estudio en la Ciudad de México. Los datos se obtuvieron mediante el método etnográfico combinando la observación directa con entrevistas semiestructuradas y registros fotográficos. La discusión plantea que el espacio planeado desde las dimensiones arquitectónica y publicitaria fomenta una dinámica urbana y comercial, la cual se ve complejizada y complementada con las prácticas de sus usuarios. Las ideas concluyentes muestran la importancia de la experiencia sensorial que ofrece un espacio, no sólo en términos de sus objetos, sino también por los procesos perceptivos y significativos que se desencadenan en las interacciones con el mismo y con los otros.