24,118 research outputs found
Bifurcation analysis and phase diagram of a spin-string model with buckled states
We analyze a one-dimensional spin-string model, in which string oscillators
are linearly coupled to their two nearest neighbors and to Ising spins
representing internal degrees of freedom. String-spin coupling induces a
long-range ferromagnetic interaction among spins that competes with a spin-spin
antiferromagnetic coupling. As a consequence, the complex phase diagram of the
system exhibits different flat rippled and buckled states, with first or second
order transition lines between states. The two-dimensional version of the model
has a similar phase diagram, which has been recently used to explain the
rippled to buckled transition observed in scanning tunnelling microscopy
experiments with suspended graphene sheets. Here we describe in detail the
phase diagram of the simpler one-dimensional model and phase stability using
bifurcation theory. This gives additional insight into the physical mechanisms
underlying the different phases and the behavior observed in experiments.Comment: 15 pages, 7 figure
Learning the dynamics of articulated tracked vehicles
In this work, we present a Bayesian non-parametric approach to model the motion control of ATVs. The motion control model is based on a Dirichlet Process-Gaussian Process (DP-GP) mixture model. The DP-GP mixture model provides a flexible representation of patterns of control manoeuvres along trajectories of different lengths and discretizations. The model also estimates the number of patterns, sufficient for modeling the dynamics of the ATV
Models for the prediction of handling damage in citrus and peaches grading lines, related to their physical properties.
Fruit damage during harvesting and handling is a standing problem, particularly for susceptible fruits like peaches and apricots. The resulting mechanical damage is a combination of fruit properties and damage inflicting effects due to procedures and to the equipment. Nine packing lines in the region of Murcia (SE Spain) have been tested with the aid of two different-size electronic fruits IS-100. Probabilities of impacts above three preset thresholds (50 g's, 100 g's and 150 g's) were calculated for each transfer point. Interaction fruit-packing line tests have been also performed in order to study the real incidence of packing lines on natural produce: apricots (1 variety), peaches (3 v.), lemons (1 v.) and oranges (3 v.). Bruises of handled and not handled samples of fruits were compared
Estratègies de finançament dels municipis turÃstics i competitivitat: el cas dels municipis catalans
La problemà tica del finançament dels municipis turÃstics és un assumpte present en el món local des de fa anys, tot i que no ha trobat una adequada resposta, ni de les administracions, ni des d’un punt de vista acadèmic. Aquest treball pretén avaluar si les finances locals representen un problema per a l’activitat turÃstica i quines serien les possibles solucions. Dels resultats de la investigació es desprèn que Els municipis turÃstics no tenen ni unes despeses, ni uns ingressos per capita superiors als dels no turÃstics. Conseqüentment, tampoc presenten problemes de dèficit especials. El que es produeix és una redistribució interna de la despesa en perjudici de la relacionada amb una baixa vinculació amb el turisme, que bà sicament té per destinatà ria la població resident.The matter of funding tourist destinations has been a problem present at a local level for many years, although a satisfactory answer has never been found, be it from public sectors or from an academic point of view. This article seeks to evaluate if local finances represent a problem for tourist activities and what could constitute possible solutions. Research shows that a tourist resort does not have higher costs nor higher incomes per capita in comparison to not touristic towns and cities. Consequently, they do not present specific problems of deficit. However what does appear is an internal redistribution of costs to the detriment of local budgetary needs which are not necessarily linked to tourism but rather to those destined to the resident population
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