A Unified Framework for Compositional Fitting of Active Appearance Models

Active Appearance Models (AAMs) are one of the most popular and well-established techniques for modeling deformable objects in computer vision. In this paper, we study the problem of fitting AAMs using Compositional Gradient Descent (CGD) algorithms. We present a unified and complete view of these algorithms and classify them with respect to three main characteristics: i) cost function; ii) type of composition; and iii) optimization method. Furthermore, we extend the previous view by: a) proposing a novel Bayesian cost function that can be interpreted as a general probabilistic formulation of the well-known project-out loss; b) introducing two new types of composition, asymmetric and bidirectional, that combine the gradients of both image and appearance model to derive better conver- gent and more robust CGD algorithms; and c) providing new valuable insights into existent CGD algorithms by reinterpreting them as direct applications of the Schur complement and the Wiberg method. Finally, in order to encourage open research and facilitate future comparisons with our work, we make the implementa- tion of the algorithms studied in this paper publicly available as part of the Menpo Project.Comment: 39 page

A thermodynamic counterpart of the Axelrod model of social influence: The one-dimensional case

We propose a thermodynamic version of the Axelrod model of social influence. In one-dimensional (1D) lattices, the thermodynamic model becomes a coupled Potts model with a bonding interaction that increases with the site matching traits. We analytically calculate thermodynamic and critical properties for a 1D system and show that an order-disorder phase transition only occurs at T = 0 independent of the number of cultural traits q and features F. The 1D thermodynamic Axelrod model belongs to the same universality class of the Ising and Potts models, notwithstanding the increase of the internal dimension of the local degree of freedom and the state-dependent bonding interaction. We suggest a unifying proposal to compare exponents across different discrete 1D models. The comparison with our Hamiltonian description reveals that in the thermodynamic limit the original out-of-equilibrium 1D Axelrod model with noise behaves like an ordinary thermodynamic 1D interacting particle system.Comment: 19 pages, 5 figure

Symplectic structures on quadratic Lie algebras

We study quadratic Lie algebras over a field K of null characteristic which admit, at the same time, a symplectic structure. We see that if K is algebraically closed every such Lie algebra may be constructed as the T*-extension of a nilpotent algebra admitting an invertiblederivation and also as the double extension of another quadratic symplectic Lie algebra by the one-dimensional Lie algebra. Finally, we prove that every symplectic quadratic Lie algebra is a special symplectic Manin algebra and we give an inductive classification in terms of symplectic quadratic double extensions

Strengths and weaknesses of Problem Based Learning from the professional perspective of registered nurses

Objective: to identify competency strengths and weaknesses as perceived by nursing professionals who graduated with a integrated curriculum and competency-based through Problem Based Learning in small groups. Method: an intrinsic case study method was used, which analyzes this innovation through former students (from the first class) with three years of professional experience. The data were collected through a questionnaire and discussion groups. Results: the results show that their competency level is valued in a very satisfactory manner. This level paradoxically contrasts with the lack of theoretical knowledge they perceived at the end of their education, when they started working in clinical practice. Conclusions: the teaching strategy was key to motivate an in-depth study and arouse the desire to know. In addition, Problem Based Learning favors and reinforces the decision to learn, which is that necessary in the course of professional life

Retratismo alegórigo / emblemático en la obra de Quevedo

El estudio revisa algunos hitos y funciones del retrato quevediano de alegorías. En la poesía se resalta la presentación vívida de las figuras como en un cuadro, a través del simbolismo emblemático y el vigor retórico. La prosa satírica muestra el retrato dinámico como un modo temprano. A partir del Sueño del mundo surgen célebres retratos detallantes y se funde el dinamismo y el estatismo. Un esquema retórico de la personificación que aprovecha Quevedo es el que describe el rostro, el cuerpo y adiuncta, al que versatiliza y optimiza. La prosa doctrinal tardía de Virtud militante refuerza la notación, los argumentos sueltos de la persona retórica, y el retrato simbólico-emblemático como índices de la representación. La caracterización costumbrista, la revisión paródica de los modelos artísticos, y la audaz labor conceptuosa son esencias de los bocetos. Al fin, los retratos quevedianos de alegorías irradian una intensa energía plastificante y suelen ser instrumentales en la presentación de moralidades nucleares, en bocetos independientes o en macrotextos. This article analyses mayor modes, landmarks and functions of the quevedian alegorical portrait. The poetry underlines the vivid presentation of the figures as if on a pictorical or emblematic frame, as well as the rhetorical vigor. The satirical prose shows the dynamic portrait to be an early mode. The detailed portraits come from the Sueño del mundo, along with the combination of dinamic and static representational qualities. Quevedo explores and optimises an outline of the personified portrait in rhetoric, which describes the face, the body and dress (or attributes) of the figure. The late moral prose of Virtud militante uses the description of a vice through the ‘notation’, the spare arguments of the rhetorical person and the symbolic / emblematic mode of portraiture. The satiric imprint, the parodic reading of the artistic models, and the witty labor of language, are essential aspects of the sketches. For all this, the quevedian alegorical portraits irradiate an intense plastic energy and they are usually instrumental in the presentation of central moralities, both in independent painting or in macrotexts

Quevedo y la ilustración de portadas: La vida de Marco Bruto y La caída para levantarse

Este trabajo presenta un estudio calcográfico de dos obras finales de Quevedo, las vidas de Marco Bruto y de San Pablo, que revela la promoción autorial sobre la invención de sus frontispicios, y apunta a una pasión poco transitada de su producción, con calidades inagotables para la comprensión discursiva. Quevedo no solo proporcionó el material arqueológico sobre el que se fundan las dos fachadas, sino que se congratuló de esa actividad inventiva. Ambos textos y sus portadas abren dimensiones inexploradas sobre el engarce quevediano de su ingenio plástico y discursivo, y sobre su afán coleccionista y ecléctico, facetas del escritor que solicitan estudio. De modo más concreto, también resaltan el brillo de su intuición simbólica, y su provecho hermenéutico de la imagen calcográfica, a través de la cual refuerza el rendimiento argumental de sus escritos. This is a study about the title pages of two final works by Quevedo; namely, the lives of Marco Bruto and San Pablo. Both works reveal the authorial promotion on the invention of both book fronts, and points out a scarcely analysed field of the author’s production which has fruitful implications on the understanding of his overall production. Quevedo did not only provided both title-pages with the archaeological material on which they are founded, but he too promoted himself for that invention. Both texts and their front pages open novel nuances about Quevedo’s combination of his discursive and plastic genius, and about his collector and eclectic spirit, decidedly, spheres of his creation which need revision. More specifically, they also underline his brilliant symbolic intuition and the peculiar profit that he attains of the engraved page, through which he wittily strengthens the line-plot of his writings