Classification of Text Documents Using a Logical Analysis Approach.

The main problem investigated in this dissertation is as follows: Given are two samples of documents each from one of two disjoint collections of documents. The question is how to obtain a set of patterns of text features that make a document in the two samples (and other unclassified documents) to be classified correctly in one and only one document class. A sample of 2,897 documents from the TIPSTER collection was used to investigate this problem. This problem was divided into the following four subproblems. The first subproblem consists of identifying the set keywords to describe the documents\u27 content. Computational results of twenty experiments suggested that single-word keywords addressed the main problem effectively. The second subproblem requires a methodology to construct classification rules to infer the class of unclassified documents. A logical analysis approach called the One Clause At a Time algorithm (OCAT) is used to address this problem. Its accuracy is compared to the one of the Vector Space Model (VSM), a benchmarking methodology in document classification processes. Under identical experimental conditions, some computational results suggests that the OCAT algorithm is more accurate than the VSM to solve the main problem. The third subproblem consists of providing a methodology to construct better rules as more documents become available. This problem has been investigated using the OCAT algorithm under a guided and a random teaming approach. Computational results on three samples of 510 documents indicate that the guided teaming approach constructs more accurate rules. In the fourth subproblem an incremental version of the OCAT algorithm is required. The algorithm is needed to speed up the construction of the classification rules. Computational results on three samples of 336 documents each show that: (i) the classification rules become accurate more rapidly, (ii) the CPU times are substantially reduced, and ( iii) the rules become more complex as more documents were added to the experiment. In summary, the results of this research suggest with high confidence that the incremental OCAT algorithm can perform better than the VSM and that it can deliver better and faster results for the classification of large collections of documents

Online guidance updates using neural networks

The aim of this article is to present a method for the online guidance update for a launcher ascent trajectory that is based on the utilization of a neural network approximator. Generation of training patterns and selection of the input and output spaces of the neural network are presented, and implementation issues are discussed. The method is illustrated by a 2-dimensional launcher simulation.Fil: Filici, Cristian. Universidad de Buenos Aires; ArgentinaFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The complex dust formation zone of the AGB star IRC+10216 probed with CARMA 0.25 arcsec angular resolution molecular observations

We present low spectral resolution molecular interferometric observations at 1.2 mm obtained with the Combined Array for Research in Millimetre-wave Astronomy (CARMA) towards the C-rich AGB star IRC+10216. We have mapped the emission of several lines of SiS, H13CN, SiO, and SiC2 in the ground and first excited vibrational states with a high angular resolution of 0.25 arcsec. These observations have allowed us to partially resolve the emission of the envelope at distances from the star <50 stellar radii (R*), where the stellar wind is mainly accelerated. The structure of the molecular emission has been modelled with a 3D radiation transfer code. The emission of line SiS(v=0,J=14-13) is best reproduced with a set of maser emitting arcs arranged between 5 and 20 R*. The abundance of H13CN with respect to H2 decreases from 8e-7 at 1-5 R* to 3e-7 at 20 R*. The SiO observations are explained with an abundance <2e-8 in the shell-like region between 1 and 5 R*. At this point, the SiO abundance sharply increases up to (2-3)e-7. The vibrational temperature of SiO increases by a factor of 2 due North-East between 20 and 50 R*. SiC2 is formed at the stellar surface with an abundance of 8e-7 decreasing down to 8e-8 at 20 R* probably due to depletion on to dust grains. Several asymmetries are found in the abundance distributions of H13CN, SiO, and SiC2 which define three remarkable directions (North-East, South-Southwest, and South-East) in the explored region of the envelope. There are some differences between the red- and blue-shifted emissions of these molecules suggesting the existence of additional asymmetries in their abundance distributions along the line-of-sight.Comment: 22 pages, 16 figures, 9 tables, accepted for publication in MNRA

Optimization of Energy Distribution in Solar Panel Array Configurations by Graph Theory and Minkowski’s Paths

Nowadays, the development of the photovoltaic (PV) technology is consolidated as a source of renewable energy. The research in the topic of maximum improvement on the energy efficiency of the PV plants is today a major challenge. The main requirement for this purpose is to know the performance of each of the PV modules that integrate the PV field in real time. In this respect, a PLC communications based Smart Monitoring and Communications Module, which is able to monitor at PV level their operating parameters, has been developed at the University of Malaga. With this device you can check if any of the panels is suffering any type of overriding performance, due to a malfunction or partial shadowing of its surface. Since these fluctuations in electricity production from a single panel affect the overall sum of all panels that conform a string, it is necessary to isolate the problem and modify the routes of energy through alternative paths in case of PV panels array configuration.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A novel design approach for switched LPV controllers

A novel design procedure for switched linear parameter-varying (LPV) controller is proposed. The new procedure, based on the Youla parameterisation ideas, decomposes the controller design into two steps. One focuses on ensuring global stability and the other on fulfilling the local performance specifications. This scheme allows the design of each local controller independently of each other, which may achieve higher performance without compromising the global stability and also simplifies the synthesis and the implementation of the local controllers. Any standard LPV synthesis procedure can be used to design these controllers. On the other hand, the stability during switching is ensured with convex constraints and no restrictions are imposed on the switching among controllers. The use of the proposed procedure is illustrated with an active magnetic bearing example.Fil: Bianchi, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Politécnica de Catalunya; EspañaFil: Sanchez Peña, Ricardo Salvador. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; Argentin

Active noise hybrid time-varying control for motorcycle helmets

Recent noise at work regulations in the EU (2003) have been established to prevent noise induced hearing loss (NIHL). This imposes better performance results to traditional feedback active noise control (ANC) in motorcycle helmets, which suffer from well known limitations. Here two new ideas are applied to this problem. First, an hybrid (feedforward/feedback) linear time invariant (LTI) controller is designed for a motorcycle helmet ANC, which improves the resulting attenuation. This is achieved by adding an extra pair of microphones which measure the external noise that is then used as the feedforward input signal. In addition and to increase even more the resulting performance, the air velocity is measured in real-time and used as the parameter which schedules a linear parameter varying (LPV) feedback (FB) controller. This is combined with the previous feedforward (FF) controller, resulting in a time-varying hybrid controller. Both hybrid, LTI and LPV controllers are designed using linear matrix inequality (LMI)-based optimization. Two experiments have been carried out to measure the relation between external noise spectra and velocity: a wind tunnel test and a freeway ride experience. The resulting controllers are tested in a simulation which uses actual data obtained from the freeway experiment. The resulting attenuations in this motivating study seem promising for future controller tests to be performed in real-time, with the adequate hardware.Fil: Castañé Selga, Rosa. Universitat Technical Zu Munich; AlemaniaFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Dual refractive index and viscosity sensing using polymeric nanofibers optical structures

Porous materials have demonstrated to be ideal candidates for the creation of optical sensors with very high sensitivities. This is due both to the possibility of infiltrating the target substances into them and to their notable surface-to-volume ratio that provides a larger biosensing area. Among porous structures, polymeric nanofibers (NFs) layers fabricated by electrospinning have emerged as a very promising alternative for the creation of low-cost and easy-to-produce high performance optical sensors, for example, based on Fabry-Perot (FP) interferometers. However, the sensing performance of these polymeric NFs sensors is limited by the low refractive index contrast between the NFs porous structure and the target medium when performing in-liquid sensing experiments, which determines a very low amplitude of the FP interference fringes appearing in the spectrum. This problem has been solved with the deposition of a thin metal layer (∼ 3 nm) over the NFs sensing layer. We have successfully used these metal-coated FP NFs sensors to perform several real-time and in-flow refractive index sensing experiments. From these sensing experiments, we have also determined that the sponge-like structure of the NFs layer suffers an expansion/compression process that is dependent of the viscosity of the analyzed sample, what thus gives the possibility to perform a simultaneous dual sensing of refractive index and viscosity of a fluid

Urban Habitability in Public Space, the Historic Center of Toluca, State of Mexico Case

La ciudad, visualizada como el hábitat predominante del hombre contemporáneo, ha venido sufriendo una notoria degradación ambiental y de la vida social. Por ello, temas relativos a lo habitable de los espacios públicos, surgen con gran fuerza sobre todo en América Latina, donde la generalidad de prácticas urbanas no trae implícitos parámetros de calidad que ofrezcan un nivel de vida apropiado a sus habitantes.Esta investigación tiene como objetivo presentar un esquema metodológico para la evaluación de la habitabilidad de los espacios públicos del centro histórico de Toluca, empleando parámetros “universales” enfocados en adultos mayores y usuarios de sillas de ruedas principalmente. Se evaluó la accesibilidad peatonal mediante el paso entre calles, facilidad para caminar por conectividad de calles, percepción de inseguridad ante la delincuencia y ruido ambiental dB(A). Se realizaron mediciones in situ, con imágenes satelitales y encuestas a peatones. La unidad de estudio, bloques de 400 x 400 m. En el centro histórico se identificó inequidad en los accesos y una navegación peatonal difícil. La percepción de seguridad se muestra degradada y con un entorno ruidoso, sobre todo en la región central. El método propuesto integró información mixta con un enfoque holístico y el empleo de la escala a nivel de barrio aporta un valor añadido. Como limitantes resaltamos que la proyección espacial no siempre ofrece explicaciones causales, faltan elementos de evaluación global y se han dejado muchas variables de habitabilidad por resolver. En conclusión, los espacios públicos requieren especial atención para hacerlos habitables y equitativos, empezando por su evaluación e implicación en políticas públicas y de gestión.Universidad Autónoma del Estado de México - Universidad Juárez Autónoma de Tabasc