386 research outputs found
Associative polynomial functions over bounded distributive lattices
The associativity property, usually defined for binary functions, can be
generalized to functions of a given fixed arity n>=1 as well as to functions of
multiple arities. In this paper, we investigate these two generalizations in
the case of polynomial functions over bounded distributive lattices and present
explicit descriptions of the corresponding associative functions. We also show
that, in this case, both generalizations of associativity are essentially the
same.Comment: Final versio
Preassociative aggregation functions
The classical property of associativity is very often considered in
aggregation function theory and fuzzy logic. In this paper we provide
axiomatizations of various classes of preassociative functions, where
preassociativity is a generalization of associativity recently introduced by
the authors. These axiomatizations are based on existing characterizations of
some noteworthy classes of associative operations, such as the class of
Acz\'elian semigroups and the class of t-norms.Comment: arXiv admin note: text overlap with arXiv:1309.730
A sensor fusion layer to cope with reduced visibility in SLAM
Mapping and navigating with mobile robots in scenarios with reduced visibility, e.g. due to smoke, dust, or fog, is still a big challenge nowadays. In spite of the tremendous advance on Simultaneous Localization and Mapping (SLAM) techniques for the past decade, most of current algorithms fail in those environments because they usually rely on optical sensors providing dense range data, e.g. laser range finders, stereo vision, LIDARs, RGB-D, etc., whose measurement process is highly disturbed by particles of smoke, dust, or steam. This article addresses the problem of performing SLAM under reduced visibility conditions by proposing a sensor fusion layer which takes advantage from complementary characteristics between a laser range finder (LRF) and an array of sonars. This sensor fusion layer is ultimately used with a state-of-the-art SLAM technique to be resilient in scenarios where visibility cannot be assumed at all times. Special attention is given to mapping using commercial off-the-shelf (COTS) sensors, namely arrays of sonars which, being usually available in robotic platforms, raise technical issues that were investigated in the course of this work. Two sensor fusion methods, a heuristic method and a fuzzy logic-based method, are presented and discussed, corresponding to different stages of the research work conducted. The experimental validation of both methods with two different mobile robot platforms in smoky indoor scenarios showed that they provide a robust solution, using only COTS sensors, for adequately coping with reduced visibility in the SLAM process, thus decreasing significantly its impact in the mapping and localization results obtained
A sensor fusion layer to cope with reduced visibility in SLAM
Mapping and navigating with mobile robots in scenarios with reduced visibility, e.g. due to smoke, dust, or fog, is still a big challenge nowadays. In spite of the tremendous advance on Simultaneous Localization and Mapping (SLAM) techniques for the past decade, most of current algorithms fail in those environments because they usually rely on optical sensors providing dense range data, e.g. laser range finders, stereo vision, LIDARs, RGB-D, etc., whose measurement process is highly disturbed by particles of smoke, dust, or steam. This article addresses the problem of performing SLAM under reduced visibility conditions by proposing a sensor fusion layer which takes advantage from complementary characteristics between a laser range finder (LRF) and an array of sonars. This sensor fusion layer is ultimately used with a state-of-the-art SLAM technique to be resilient in scenarios where visibility cannot be assumed at all times. Special attention is given to mapping using commercial off-the-shelf (COTS) sensors, namely arrays of sonars which, being usually available in robotic platforms, raise technical issues that were investigated in the course of this work. Two sensor fusion methods, a heuristic method and a fuzzy logic-based method, are presented and discussed, corresponding to different stages of the research work conducted. The experimental validation of both methods with two different mobile robot platforms in smoky indoor scenarios showed that they provide a robust solution, using only COTS sensors, for adequately coping with reduced visibility in the SLAM process, thus decreasing significantly its impact in the mapping and localization results obtained
El pistachero II: Estudio fenológico y económico
10 páginas, tablas estadísticas y figuras.El pistachero es capaz de sobrevivir y dar frutos en situaciones adversas,
intolerables para la mayor parte de los frutales. Sin embargo también tiene unos
condicionamientos de medio bastantes específicos que limitan su posible área de
cultivo, como son las necesidades en frío para cubrir adecuadamente su periodo de
reposos invernal, la sincronía en la floración de machos y hembras para tener una
buena polinización y sensibilidad a las heladas tardías de primavera. Con los
resultados obtenidos en este trabajo y en el trabajo presentado en este VI Congreso
de la SEAE “El pistachero I: Estudio de variedades en secano y en manejo ecológico”,
se realiza un estudio de viabilidad económica.
Se recomienda que a la hora de hacer una nueva plantación, se incluya en la
misma diferentes variedades hembras y machos. Las variedades hembras con las que
se han obtenido mejores resultados son: Avdat, Ashoury y Larnaka, y como
polinizadores: C-especial, Askar, Nazar, Chico y Mateur.
Las variedades recomendadas, tienen unas necesidades cercanas a las 1.000
horas-frío para el inicio de la actividad vegetativa y la floración es en la primera
quincena de abril.
En el estudio económico y considerando que sólo uno de cada tres años se
obtiene producción, debido a problemas de heladas de primavera o por veceria, se
pueden obtener una rentabilidad económica, a partir de los veinte años, superior a los
600 €, lo que le permite ser una buena alternativa para algunas zonas del secano españolPeer reviewe
Hybrid adaptive control of a dragonfly model
Dragonflies show unique and superior flight performances than most of other insect species
and birds. They are equipped with two pairs of independently controlled wings granting
an unmatchable flying performance and robustness.
In this paper, it is presented an adaptive scheme controlling a nonlinear model inspired
in a dragonfly-like robot. It is proposed a hybrid adaptive (HA) law for adjusting the parameters
analyzing the tracking error. At the current stage of the project it is considered essential
the development of computational simulation models based in the dynamics to test
whether strategies or algorithms of control, parts of the system (such as different wing
configurations, tail) as well as the complete system. The performance analysis proves the
superiority of the HA law over the direct adaptive (DA) method in terms of faster and
improved tracking and parameter convergence
Application of fractional algorithms in the control of a robotic bird
In this paper, it is studied the dynamics of the robotic bird in terms of time response and robustness. It is analyzed the wing angle of attack and the velocity of the bird, the tail influence, the gliding flight and the flapping flight. The results are positive for the construction of flying robots. The development of computational simulation based on the dynamic of the robotic bird should allow testing strategies and different algorithms of control such as integer and fractional controllers
Dynamical Stability and Predictability of Football Players: The Study of One Match
The game of football demands new computational approaches to measure individual and collective performance. Understanding the phenomena involved in the game may foster the identification of strengths and weaknesses, not only of each player, but also of the whole team. The development of assertive quantitative methodologies constitutes a key element in sports training. In football, the predictability and stability inherent in the motion of a given player may be seen as one of the most important concepts to fully characterise the variability of the whole team. This paper characterises the predictability and stability levels of players during an official football match. A Fractional Calculus (FC) approach to define a player’s trajectory. By applying FC, one can benefit from newly considered modeling perspectives, such as the fractional coefficient, to estimate a player’s predictability and stability. This paper also formulates the concept of attraction domain, related to the tactical region of each player, inspired by stability theory principles. To compare the variability inherent in the player’s process variables (e.g., distance covered) and to assess his predictability and stability, entropy measures are considered. Experimental results suggest that the most predictable player is the goalkeeper while, conversely, the most unpredictable players are the midfielders. We also conclude that, despite his predictability, the goalkeeper is the most unstable player, while lateral defenders are the most stable during the match
A fuzzified systematic adjustment of the robotic Darwinian PSO
The Darwinian Particle Swarm Optimization (DPSO) is an evolutionary algorithm that extends the Particle
Swarm Optimization using natural selection to enhance the ability to escape from sub-optimal solutions.
An extension of the DPSO to multi-robot applications has been recently proposed and denoted as Robotic
Darwinian PSO (RDPSO), benefiting from the dynamical partitioning of the whole population of robots,
hence decreasing the amount of required information exchange among robots. This paper further extends
the previously proposed algorithm adapting the behavior of robots based on a set of context-based
evaluation metrics. Those metrics are then used as inputs of a fuzzy system so as to systematically
adjust the RDPSO parameters (i.e., outputs of the fuzzy system), thus improving its convergence rate,
susceptibility to obstacles and communication constraints. The adapted RDPSO is evaluated in groups
of physical robots, being further explored using larger populations of simulated mobile robots within a
larger scenario
Saccharomyces cerevisiae as a toxicological model to study synthetic cannabinoids and its pyrolysis products
Poster presented at the 7th European Academy of Forensic Science Conference. Prague, 6-11 September 2015"Synthetic cannabinoids are among the major psychoactive drugs widespread as safe and legal alternatives to cannabis. They are commercially available as herbal incense products intended for smoke. This has led most of developed countries to concentrate efforts in order to ban the so called “legal highs”. Despite of their increasing use, there is still a lack of information on both synthetic and natural ingredients, pharmacokinetic properties and toxic effects. In fact some of the substances seem to have stronger toxicological effects when compared to their legal counterpart. Toxicological assays are paramount to know how harmful these new substances are, helping increase public awareness since several hospitalization cases have been reported due to consumption. To tackle the new challenges posed by novel drugs worldwide, we developed an approach using Saccharomyces cerevisiae as a model to investigate the toxicity of pyrolysis products of synthetic cannabinoids. S. cerevisiae.
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