Suboptimal triangular controller design methodology for full MIMO stable systems

This paper proposes a design methodology of triangular controllers for full MIMO stable plants. The procedure is based on an optimal design for a triangular model of the plant. Stability and appropriate performance can be achieved by adjusting a set of design parameters involved in a weighting function. The resulting controller provides integration and can be computed analytically

Evaluación de la amenaza sísmica de Colombia. Actualización y uso en las nuevas normas colombianas de diseño sismo resistente NSR-10

La disponibilidad de modelos y técnicas de cálculo más refinadas para la evaluación de la amenaza sísmica, así como la existencia de una mayor cantidad de registros de eventos sísmicos, permite realizar una actualización de los estudios de amenaza sísmica a nivel nacional. Este artículo describe la nueva metodología utilizada para estimar diferentes intensidades sísmicas esperadas para diseño y construcción de edificaciones sismorresistentes en el territorio colombiano. Se presentan los resultados de intensidad obtenidos para diferentes períodos de retorno y ordenadas espectrales para edificaciones de diferentes períodos estructurales, los cuales, además de servir para establecer los valores de diseño en las nuevas Normas NSR-10, también son un insumo necesario para la realización de estudios de microzonificación y de riesgo sísmico dentro del territorio nacional de la República de Colombia

The use of GIS and Multi-Criteria evaluation (MCE) to determine scenarios of potential floodings in fluvial basins : study case: cuenca Guanabo, Habana city

El trabajo muestra la potencialidad que presentan los Sistemas de Información Geográfica (SIG) y la evaluación multicriterio (EMC), para determinar con precisión, la cartografía de las zonas susceptibles al desarrollo de inundaciones recurrentes en cuencas fluviales. La capacidad de análisis y manejo de la información espacial que poseen los SIG en la actualidad, conjuntamente con el procesamiento estadístico apoyados en el uso de la EMC, permiten cuantificar factores del medio natural y establecer grados de adecuación, reduciendo la subjetividad durante el procesamiento analítico. Las zonas susceptibles determinadas con el empleo de esta metodología se comparó con estudios anteriores y los resultados presentan una buena coincidencia espacial aunque ésta mejora en precisión cartográfica. Sin duda los resultados obtenidos constituyen valiosas herramientas de gestión, los cuales ayudan a la toma de decisiones en los territorios e incrementan el nivel de conocimiento para reducir los riesgos de desastres naturales.The work shows the potential that Geographic Information Systems and Multi-Criteria Evaluation (EMC) have, to determine accurately, the cartography of favorable areas to recurrent floods development in fluvial basins. The analysis and special information handling capacity that the SIGs have nowadays, together with statistic processing resting in the (EMC) use, make it possible to quantify natural resources factors and establish degrees of fitness, reducing subjectivity during analytic processing. The capable zones determined with the employment of this methodology were compared with previous studies and the result presents a good spatial coincidence though this one improves in cartographic precision. Certainly, the results obtained become valuable management tools that help territory decision making and increase knowledge level to reduce natural disasters risks.Fil: Olivera Acosta, Jorge. La Habana (Cuba). Agencia de medio ambienteFil: Morales, Gustavo Martín. La Habana (Cuba). Agencia de medio ambienteFil: García Rivero, Alberto E.. La Habana (Cuba). Agencia de medio ambienteFil: Salgado, Efrén Jaimez. La Habana (Cuba). Agencia de medio ambienteFil: López, Martin Luis. La Habana (Cuba). Agencia de medio ambienteFil: Estrada, Reinaldo. La Habana (Cuba). Agencia de medio ambienteFil: Campos Dueñas, Mario. La Habana (Cuba). Agencia de medio ambienteFil: Miravet, Bárbara Liz. La Habana (Cuba). Agencia de medio ambient

The Carnegie Supernova Project: Analysis of the First Sample of Low-Redshift Type-Ia Supernovae

We present the analysis of the first set of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project. Well-sampled, high-precision optical (ugriBV) and near-infrared (NIR; YJHKs) light curves obtained in a well-understood photometric system are used to provide light-curve parameters, and ugriBVYJH template light curves. The intrinsic colors at maximum light are calibrated to compute optical--NIR color excesses for the full sample, thus allowing the properties of the reddening law in the host galaxies to be studied. A low value of Rv~1.7, is derived when using the entire sample of SNe. However, when the two highly reddened SNe in the sample are excluded, a value Galactic standard of Rv~3.2 is obtained. The colors of these two events are well matched by a reddening model due to circumstellar dust. The peak luminosities are calibrated using a two-parameter linear fit to the decline rates and the colors, or alternatively, the color excesses. In both cases, dispersions in absolute magnitude of 0.12--0.16 mag are obtained, depending on the filter-color combination. In contrast to the results obtained from color excesses, these fits give Rv~1--2, even when the two highly reddened SNe are excluded. This discrepancy suggests that, beyond the "normal" interstellar reddening produced in the host galaxies, there is an intrinsic dispersion in the colors of SNe Ia which is correlated with luminosity but independent of the decline rate. Finally, a Hubble diagram is produced by combining the results of the fits for each filter. The resulting scatter of 0.12 mag appears to be limited by peculiar velocities as evidenced by the strong correlation between the distance-modulus residuals among the different filters. The implication is that the actual precision of SN Ia distances is 3--4%.Comment: 76 pages, 20 figures, accepted for publication in A

Hacia un modelo integral de accesibilidad en sistemas e-learning

Con el transcurso del tiempo, las actividades humanas, se han ido modificando, desde el ocio hasta el entablar una conversación, se vieron afectadas por la implementación de tecnologías. La educación, no está exceptuada, ya que cada día toman más impulso los sistemas de aprendizaje en línea mediados por tecnología, apuntando a una educación virtual, que se ha consolidado como una gran alternativa en los procesos de enseñanza-aprendizaje. En este sentido, esta línea de investigación plantea la importancia de incorporar condiciones de accesibilidad en los entornos virtuales de aprendizaje, a través de la definición de métricas a partir de la identificación de algunos criterios que permiten cuantificar el grado de satisfacción de los usuarios.Eje: Ingeniería de Software.Red de Universidades con Carreras en Informátic

The Carnegie Supernova Project: First Photometry Data Release of Low-Redshift Type Ia Supernovae

The Carnegie Supernova Project (CSP) is a five-year survey being carried out at the Las Campanas Observatory to obtain high-quality light curves of ~100 low-redshift Type Ia supernovae in a well-defined photometric system. Here we present the first release of photometric data that contains the optical light curves of 35 Type Ia supernovae, and near-infrared light curves for a subset of 25 events. The data comprise 5559 optical (ugriBV) and 1043 near-infrared (YJHKs) data points in the natural system of the Swope telescope. Twenty-eight supernovae have pre-maximum data, and for 15 of these, the observations begin at least 5 days before B maximum. This is one of the most accurate datasets of low-redshift Type Ia supernovae published to date. When completed, the CSP dataset will constitute a fundamental reference for precise determinations of cosmological parameters, and serve as a rich resource for comparison with models of Type Ia supernovae.Comment: 93 pages, 8 figures, accepted for publication in A

The Distance to NGC 1316 (Fornax A) From Observations of Four Type Ia Supernovae

The giant elliptical galaxy NGC 1316 (Fornax A) is a well-studied member of the Fornax Cluster and a prolific producer of Type Ia supernovae, having hosted four observed events since 1980. Here we present detailed optical and near-infrared light curves of the spectroscopically normal SN 2006dd. These data are used, along with previously published photometry of the normal SN 1980N and SN 1981D, and the fast-declining, low-luminosity SN 2006mr, to compute independent estimates of the host reddening for each supernova, and the distance to NGC 1316. From the three normal supernovae, we find a distance of 17.8 +/- 0.3 (random) +/- 0.3 (systematic) Mpc for Ho = 72. Distance moduli derived from the "EBV" and Tripp methods give values that are mutually consistent to 4 -- 8%. Moreover, the weighted means of the distance moduli for these three SNe for three methods agree to within 3%. This consistency is encouraging and supports the premise that Type Ia supernovae are reliable distance indicators at the 5% precision level or better. On the other hand, the two methods used to estimate the distance of the fast-declining SN 2006mr both yield a distance to NGC 1316 which is 25-30% larger. This disparity casts doubt on the suitability of fast-declining events for estimating extragalactic distances. Modest-to-negligible host galaxy reddening values are derived for all four supernovae. Nevertheless, two of them (SN 2006dd and SN 2006mr) show strong NaID interstellar lines in the host galaxy system. The strength of this absorption is completely inconsistent with the small reddening values derived from the supernova light curves if the gas in NGC 1316 is typical of that found in the interstellar medium of the Milky Way. In addition, the equivalent width of the NaID lines in SN 2006dd appear to have weakened significantly some 100-150 days after explosion.Comment: 50 pages, 13 figures, 10 tables; constructive comments welcome. Accepted for publication in A

SN 2009bb: a Peculiar Broad-Lined Type Ic Supernova

Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudo-bolometric light curve of SN 2009bb suggests that 4.1+-1.9 Msun of material was ejected with 0.22 +-0.06 Msun of it being 56Ni. The resulting kinetic energy is 1.8+-0.7x10^52 erg. This, together with an absolute peak magnitude of MB=-18.36+-0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission, and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for GRBs, we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of gamma-ray instruments.Comment: Accepted for publication in Ap

An Influenza A/H1N1/2009 Hemagglutinin Vaccine Produced in Escherichia coli

The A/H1N1/2009 influenza pandemic made evident the need for faster and higher-yield methods for the production of influenza vaccines. Platforms based on virus culture in mammalian or insect cells are currently under investigation. Alternatively, expression of fragments of the hemagglutinin (HA) protein in prokaryotic systems can potentially be the most efficacious strategy for the manufacture of large quantities of influenza vaccine in a short period of time. Despite experimental evidence on the immunogenic potential of HA protein constructs expressed in bacteria, it is still generally accepted that glycosylation should be a requirement for vaccine efficacy.We expressed the globular HA receptor binding domain, referred to here as HA(63-286)-RBD, of the influenza A/H1N1/2009 virus in Escherichia coli using a simple, robust and scalable process. The recombinant protein was refolded and purified from the insoluble fraction of the cellular lysate as a single species. Recombinant HA(63-286)-RBD appears to be properly folded, as shown by analytical ultracentrifugation and bio-recognition assays. It binds specifically to serum antibodies from influenza A/H1N1/2009 patients and was found to be immunogenic, to be capable of triggering the production of neutralizing antibodies, and to have protective activity in the ferret model.Projections based on our production/purification data indicate that this strategy could yield up to half a billion doses of vaccine per month in a medium-scale pharmaceutical production facility equipped for bacterial culture. Also, our findings demonstrate that glycosylation is not a mandatory requirement for influenza vaccine efficacy