3,517 research outputs found
Sistema de visualización remota de entornos mediante realidad virtual
Este Trabajo de Fin de Grado busca solucionar uno de los problemas de las actuales cámaras IP o “webcams”: el ángulo de visión. En general son cámaras fijas, que sólo captan una fracción del entorno que las rodea. Si bien existe la posibilidad de dotar a estas de elementos mecánicos que permitan su rotación, aunque estos mecanismos aumentan considerablemente su precio, incluyendo el de mantenimiento. Más aún, incluso en este caso sólo un usuario puede controlar su orientación en cada momento, ya que no es posible que este apuntando en dos direcciones simultáneamente.
Con este proyecto se pretende cambiar esta situación, de tal manera que por un precio reducido se pueda construir un sistema capaz de captar al mismo tiempo información de todo su entorno y de transmitir ésta a distintos usuarios para que cada uno pueda ver los fragmentos que le interesan, independientemente de que sean los mismos o no. Existen distintas soluciones que pueden satisfacer este objetivo, con mejores o peores resultados. Entre ellas, la que mejor relación calidad precio ofrece es el uso de una lente panorámica, ya que solo requiere de una cámara y las imágenes que proporciona son fácilmente traducidas. Sin embargo, el resultado de esta traducción es simplemente una imagen con toda la información. Por tanto, aquí es necesario introducir una interfaz que permita que el cliente interactúe con los datos de forma natural e intuitiva y qué mejor manera que el uso del propio cuerpo del usuario, junto con un casco de realidad virtual, para posibilitar este control.
Aquí se desarrollará un sistema que permitirá visualizar secciones de imágenes panorámicas desde dispositivos móviles u ordenadores. Dicho sistema contará con un módulo de software que capturará imágenes y generará a partir de estas las panorámicas, y una aplicación web que las mostrará a través de un navegador en el dispositivo cliente. Todo ello en conjunto, posibilitará que múltiples usuarios tengan acceso a toda la información concurrentemente, de tal manera que cada uno pueda visualizar la sección que desee si interferir en las operaciones del resto.
Para hacer posible esta solución, también es vital disponer de un hardware de bajo coste pero con buen rendimiento, debido a que el procesamiento de imágenes es costoso. Por esa razón, se ha escogido la Raspberry Pi 2 como base para este trabajo. Adicionalmente también se hará uso de su módulo de cámara y de un adaptador Wi-Fi para proporcionar tanto conectividad local como remota.This Bachelor Thesis attempts to find a solution to one of the problems with current IP cameras or webcams: the angle of vision. In general, these cameras are fixed, and because of this, only capable of capturing a fraction of their surroundings. Even though it is possible to equip them with mechanical elements that allow them to rotate, these mechanisms raise their cost considerably. Moreover, even in these cases, this movement can only be controlled by one user at a time because the camera cannot point in two different directions simultaneously.
With this project, this situation is meant to change for the better, in a way that it will make possible the production of a device capable of registering information of all of its surroundings at the same time and transmitting said information to multiple clients, so that each one can view the fragments that they are interested in independently of them being the same or not, at a fraction of the cost. For this task there are many different solutions available, with better or worse results. Among these, the one with a better cost/quality ratio implies the use of a panoramic lens, because this method requires only one camera and the images it provides are easily translated. On the other hand, the result of this translation is just a plain panoramic image containing all of the information. Thus, there is a need to introduce an interface that will allow the client to interact with the data in a natural and intuitive manner, and what better way to do this than by letting the user use their own body paired with the use of a VR headset to achieve this control.
Here, I will develop a system that will allow the viewing of fragments of panoramic images from mobile devices and computers. This system will consist of, a software module that will capture images and convert them to a panoramic format, and a web application that will show these images through a browser on a client device. All of this, will allow multiple users to have access to all of the information at the same time, in a way that each one will be able to view the fragment they are interested in, without interfering with the others.
To make all of the aforementioned possible, it is also vital to build off a cheap, but powerful hardware platform, because of the high processing cost of images. For this reason, the Raspberry Pi 2 computer stands out as the best choice for the base of this project. Additionally, its camera module and a Wi-Fi adapter will also be used, in the case of the later to provide both local and remote access
Is a bad will a weak will? Cognitive dispositions modulate folk attributions of weakness of will
In line with recent efforts to empirically study the folk concept of weakness of will, we examine two issues in this paper: (1) How is weakness of will attribution [WWA] influenced by an agent’s violations of best judgment and/or resolution, and by the moral valence of the agent’s action? (2) Do any of these influences depend on the cognitive dispositions of the judging individual? We implemented a factorial 2x2x2 between–subjects design with judgment violation, resolution violation, and action valence as independent variables, and measured participants’ cognitive dispositions using Frederick’s Cognitive Reflection Test [CRT]. We conclude that intuitive and reflective individuals have two different concepts of weakness of will. The study supports this claim by showing that: a) the WWA of intuitive subjects is influenced by the action’s (and probably also the commitment’s) moral valence, while the WWA of reflective subjects is not; b) judgment violation plays a small role in the WWA of intuitive subjects, while reflective subjects treat resolution violation as the only relevant trait. Data were collected among students at two different universities. All subjects (N=710) answered the CRT. A three-way ANOVA was first conducted on the whole sample and then on the intuitive and reflective groups separately. This study suggests that differences in cognitive dispositions can significantly impact the folk understanding of philosophical concepts, and thus suggests that analysis of folk concepts should take cognitive dispositions into account
Relation-based Galois connections: towards the residual of a relation
Inma P. Cabrera, Pablo Cordero, Manuel Ojeda-Aciego, Relation-based Galois connections: towards the residual of a relation, CMMSE 2017: Proceedings of the 17th International Conference on Mathematical Methods in Science and Engineering ( ISBN: 978-84-617-8694-7) , pp. 469--475We explore a suitable generalization of the notion of Galois connection in which their components are binary relations. Many different approaches are possible depending both on the (pre-)order relation between subsets in the underlying powerdomain and the chosen type of relational composition.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Aggregate administrative data to adjust selection bias in estimates from nonprobability samples
Tesis por compendio de publicaciones[ES] En los últimos años, la concurrencia de dos fenómenos ha revitalizado el debate
metodológico sobre la inferencia a partir de muestras no probabilísticas. Por un lado, las
muestras probabilísticas adolecen cada vez más de errores derivados de la no respuesta y
la falta de cobertura, lo que aumenta los costes de las encuestas y da lugar a estimaciones
sesgadas. Por otro lado, la aparición y la expansión de internet han provocado un creci-
miento exponencial del uso de encuestas web con muestras reclutadas mediante métodos
no probabilísticos. La inferencia a partir de muestras no probabilísticas requiere un modelo
explícito o implícito que explique el mecanismo de selección con respecto a la variable
objetivo.
Esta tesis explora una intersección entre la necesidad de reducir el sesgo de selec-
ción en las estimaciones realizadas a partir de muestras no probabilísticas y la oportunidad
de explicar el mecanismo de selección que surge de los nuevos datos administrativos agre-
gados disponibles. Para ello, esta tesis engloba tres trabajos que presentan una serie de
simulaciones estadísticas y dos aplicaciones metodológicas utilizando un conjunto de en-
cuestas presenciales y dos encuestas web realizadas en España. En primer lugar, las simu-
laciones estadísticas exploran las condiciones bajo las cuales los datos agregados como
variables contextuales y totales poblacionales pueden reducir o eliminar el sesgo de selec-
ción de las estimaciones. En segundo lugar, utilizando las encuestas pre y postelectorales
del Centro de Investigaciones Sociológicas (CIS) que combinan métodos de selección pro-
babilística con cuotas, se explora la adición de variables auxiliares sociodemográficas y
recuerdo de voto a la ponderación, así como el uso de técnicas de imputación múltiple para
mejorar la calidad de las estimaciones. En tercer lugar, utilizando dos encuestas de un panel
experimental de internautas patrocinado por la Asociación para la Investigación de los Me-
dios de Comunicación (AIMC), se comprueba el efecto de incluir datos administrativos
agregados a nivel municipal para atajar el sesgo de selección y mejorar la calidad de las
estimaciones de la encuesta.
Los resultados muestran que los datos administrativos agregados son insuficientes
para corregir el sesgo de selección en las estimaciones de la encuesta, especialmente
cuando se utilizan como variables contextuales. Los resultados también sugieren que la
naturaleza agregada de los datos es el principal impedimento para controlar el sesgo de
selección en las estimaciones.
[EN] In recent years, the concurrence of two phenomena has revitalised the methodolog-
ical debate about inference from nonprobability samples. On the one hand, probability
samples increasingly suffer from nonresponse and noncoverage errors, increasing survey
costs and leading to biased estimates. On the other hand, the emergence and expansion of
the Internet have led to an exponential growth in the use of web surveys with samples
recruited using nonprobability methods. Inference from nonprobability samples requires
an explicit or implicit model that explains the selection mechanism with respect to the tar-
get variable.
This thesis explores an intersection between the need to reduce selection bias in the
estimates from nonprobability samples and the opportunity to explain the selection mech-
anism emerging from newly available aggregate administrative data. To this end, this thesis
encompasses three papers that present statistical simulations and two methodological ap-
plications using a set of face-to-face and two web surveys conducted in Spain. The first
paper uses statistical simulations to explore the conditions under which aggregated data as
contextual variables and population totals can reduce or remove selection bias from the
estimates. The second paper explores adding sociodemographic and past vote auxiliary
variables to the weighting as well as using multiple imputation to improve the quality of
the estimates using the pre and post-election surveys of the Centro de Investigaciones So-
ciológicas (CIS) that combine probability selection methods with quotas. The third article
tests the effect of including aggregate administrative data at the municipality level to tackle
selection bias and improve the quality of the survey estimates using two surveys from an
experimental panel of internet users sponsored by the Association for Media Research
(AIMC).
The results show that aggregate administrative data is insufficient to correct selec-
tion bias in survey estimates, especially when used as contextual variables. The results also suggest that the aggregate nature of the data is the main impediment to control for selection
bias in the estimates
Crisis de la representación estética ecuatoriana desde la segunda mitad del siglo XX hasta comienzos del XXI
El presente trabajo analiza de qué manera el arte ecuatoriano tiene tres rasgos que caracterizan las
experiencias estéticas desde mediados del siglo XX al presente. ‘Imposición’ porque se transfieren sin reparos
modelos estéticos que definen la producción de expresiones artísticas; ‘dominio’, debido que ese influjo
impositivo y multifuncional se considera preferente en los espacios social, cultural, artístico y académico;
‘exclusión’, en vista que existen expresiones que se consideran inoperantes en esta dominancia y se proscriben.
Esta situación proviene del paradigma de las ‘muestras estéticas’ posmodernistas, conceptualistas de tendencia
ideológica neomarxista. Esta mezcla aplicada a la estética y al arte en Ecuador, ha impuesto un régimen que es
encaminado por la ‘alta cultura’ y las prácticas del ‘arte culto’ asociadas a los alcances curatoriales, ocasionado
confusiones e inestabilidad en la producción de las expresiones artísticas, no solo de los involucrados en este
modelo, también en los que no se someten al mismo. En esta indagación se consultan fuentes a nivel nacional e
internacional y se exploran los tres rasgos enunciados en interrogatorio con las teorías e ideología que sustentan
el referido paradigma, para una interpretativa con dos instancias complementarias. La primera, se refiere a los
paradigmas estéticos y los derives en el arte contemporáneo ecuatoriano; la segunda, sobre el axioma de las
‘muestras estéticas’ y la agencia en las expresiones artísticas. La conclusión enuncia las limitaciones, aperturas y
resultados para asignar opciones al estado actual del arte y la diligencia alterna que representa la filosofía andina
para la superación de la crisis estética ecuatoriana.//This paper analyzes how Ecuadorian art has three features that characterize aesthetic
experiences from the mid-20th century to the present. ‘Imposition’, because esthetic models that
define the production of artistic expressions are transferred without qualms; ‘Domain’, because
this taxing and multifunctional influence is considered preferable in social, cultural, artistic and
academic spaces; ‘Exclusion’, given that there are expressions that are considered inoperative in this
dominance and are excluded. This situation comes from the paradigm of postmodernist ‘aesthetic
samples’, conceptualists of neo-Marxist ideological tendencies. This mixture applied to aesthetics
and art in Ecuador, has imposed a regime that is guided by the ‘high culture’ and practices of ‘cultured
art’ associated with curatorial achievements, has caused confusion and instability in the production
of artistic expressions; not only those involved in this model, but also those who do not submit to it.
In this inquiry sources are consulted at the national and international level and the two features
stated in questioning are explored with the theories and ideology that support the aforementioned
paradigm, for an interpretative one with three complementary instances. The first refers to the
aesthetic paradigms and from which Ecuadorian contemporary art derives; the second, on the
axiom of the ‘aesthetic samples’ and the agency in the artistic expressions. The conclusion states
the limitations, openings and results to assign options to the current state of art and the alternative
diligence represented by the Andean philosophy for overcoming the Ecuadorian aesthetic crisis
Recensión: Villena Higueras, J. L. y Molina Fernández, E. (Coords.). (2015). Ciudades con vida: Infancia, participación y movilidad. Barcelona: Graó. 209 páginas ISBN: 978-84-9980-573-3
Development of Metal Complexes for Use in Non-Aqueous Redox Flow Batteries and C-H Functionalization of N-Heterocycles
Batteries represent a sustainable energy storage technology for the integration of renewable resources into the electrical grid. The first part of my research focused on the development of metal complexes as redox active materials for non-aqueous redox flow batteries. Flow batteries are rechargeable batteries based on solvated electroactive species that are flowed between storage tanks and electrochemical conversion cells to store or release electrical energy.
Chapter 2 describes a systematic study on the impact of the bipyridine ligand structure on the solubility and electrochemistry of [Cr(bpy)3] complexes that afford six reversible redox couples over ∼2 V and solubilities approaching 1 M. These studies reveal that solubility is highly dependent on the oxidation state of the metal complex with solubility differences up to 4 orders of magnitude between the Cr(0) and the Cr(III) complexes. In contrast, modifications to the metal complex have minimal impact on the electrochemical properties. Furthermore, this investigation led to the identification of a promising Cr complex that was evaluated in charge/discharge experiments affording a two-electron transfer at each of the electrodes with efficiencies of 70%.
The second part of my research is focused on the development of C–H functionalization methodologies. The conversion of carbon–hydrogen (C–H) bonds into new functional groups represents a powerful strategy for the synthesis of organic molecules. The advent of C–H functionalization has enabled medicinal chemists to utilize a late-stage functionalization approach to efficiently convert the C–H bonds in drug candidates to new chemical entities. Despite tremendous progress in the field, selective C–H functionalization of N-heterocycles remains challenging.
Chapter 3 describes a room-temperature photoredox-catalyzed method for the C–H amination of hetero(arenes). This chapter describes the design and development of N-trifluoroacyloxyphthalimide as precursor to nitrogen-centered radical intermediates. N-trifluoroacyloxyphthalimide is proposed to undergo a single electron reduction by the photocatalyst leading to an imidyl radical. The C–H amination protocol addresses several limitations from previous methods such as the need for expensive oxidants and elevated temperatures. The mild reaction conditions enabled the preparation of several N-heterocyclic amine products, which are common motifs in bioactive molecules. Furthermore, the synthesis of N-trifluoroacyloxysaccharine afforded highly electrophilic N-radicals, thereby permitting further reaction optimization to lower the photocatalyst and hetero(arene) loading.
Chapter 4 describes the development of a Pd-catalyzed transannular C–H arylation of alicyclic amines. A key design principle is the use of the nitrogen atom in these substrates to direct the Pd-catalyst to remote C–H bonds in the ring. This approach leverages the high-energy boat conformer species to achieve transannular C–H activation and subsequent C–C bond formation. The reaction exhibits high compatibility with a wide range of hetero(aryl) iodides in the diversification of 3-azabicyclo[3.1.0]hexane. Several alicyclic amines undergo C–H arylation in modest to good yields. The methodology was employed for the late-stage functionalization of bioactive molecules including amitifadine, varenicline and cytisine. Furthermore, several directing groups were synthesized which showed a wide range of reactivity toward the C4–H arylation of piperidine.
Chapter 5 describes the identification of pyridinecarboxylic acid ligands for the Pd-catalyzed C–H functionalization of azabicycloalkanes. The ligand additives were found to dramatically improve the reactivity. Kinetic studies reveal that the role of the ligand is to rescue deactivated Pd species. Reaction optimization enables the challenging distal C–H functionalization of diverse alkaloids such as tropane.PHDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138771/1/pabloco_1.pd
On the notion of fuzzy adjunctions between fuzzy orders
Las adjunciones (también denominadas conexiones de Galois isótonas) entre dos estructuras matemáticas proporcionan una manera de conectar ambas teorías que permite compartir las ventajas de ambas. Hay varios resultados en la literatura previa acerca de las condiciones necesarias y suficientes para la existencia de conexiones de Galois entre dos conjuntos parcialmente ordenados. En otros trabajos anteriores, los autores han estudiado la existencia y construcción del adjunto por la derecha de una aplicación dada entre conjuntos preordenados o dotados de un orden difuso, entendido éste como una relación binaria difusa satisfaciendo reflexividad, transitividad y antisimetría. Se entiende el término adjunción difusa como una pareja de aplicaciones entre dos conjuntos crisp que están dotados de órdenes difusos para las culaes se verifica la condición ρ(a,g(b)) = ρ(f(a),b). Esta definición no está suficientemente justificada en un contexto difuso puesto que las aplicaciones que se consideran se dan entre conjuntos clásicos. En este trabajo se explica la forma en la que la citada definición está relacionada con las funciones difusas, mostrando así que la definición sí es adecuada en ambiente difuso también. La extensión natural de la noción difusa de adjunción contempla dos posibilidades, según si uno considera igualdades difusas o equivalencias difusas asociadas al orden difuso o no.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Winnerless competition in coupled Lotka-Volterra maps
Winnerless competition is analyzed in coupled maps with discrete temporal evolution of the Lotka-Volterra type of arbitrary dimension. Necessary and sufficient conditions for the appearance of structurally stable heteroclinic cycles as a function of the model parameters are deduced. It is shown that under such conditions winnerless competition dynamics is fully exhibited. Based on these conditions different cases characterizing low, intermediate, and high dimensions are therefore computationally recreated. An analytical expression for the residence times valid in the N-dimensional case is deduced and successfully compared with the simulations.J.L.C. and E.D.G. acknowledge support from IVIC-141, L.A.G.-D. acknowledges support from IVIC-1089 and P.V. acknowledges support from MINECO TIN2012-30883
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