Degrés de connaissance littéraire

Plaisir de lire et plaisir de connaître s’enrichissent mutuellement dans l’expérience littéraire. Si l’expérience littéraire, comme toute expérience esthétique, est d’abord associative, linéaire, horizontale, et paraît distincte de la connaissance par concepts, de type vertical (Schaeffer), elle peut aussi ouvrir la voie à une connaissance de troisième degré, connaissance de l’autre comme sujet ou comme relation subjective au monde. Tel est notamment le cas lorsque l’expérience littéraire prend la forme de la lecture littéraire et de son corollaire, le texte de lecture. Ce degré de la connaissance prend appui sur la faculté de juger réfléchissante telle qu’elle semble analysée dans la troisième Critique de Kant : contrairement à la vulgate kantienne qui en souligne la dimension anti-conceptuelle, la faculté de juger réfléchissante est ici envisagée comme fonction régulatrice susceptible de dépasser l’antinomie de l’objectif et du subjectif.In literary experience the pleasure of reading and the pleasure of knowing are mutually enriching. Even if literary experience, like all aesthetic experience, is first of all associative, linear and horizontal, and appears to be distinct from knowledge by concepts, of the vertical type (Schaeffer), it may also open up the way to knowledge of the third degree, that is knowledge of the other as subject or as subjective relation to the world. Such is the case in particular when literary experience takes the shape of literary reading and of its corollary, the reader’s own reformulation of the text. This degree of knowledge leans on the reflective faculty of judgment as it seems to be analyzed in Kant’s third “Critique”: contrary to the Kantian vulgate which underlines its anti-conceptual dimension, the reflective faculty of judgment is viewed here as a governing function likely to go beyond the antinomy of the objective and the subjective

Construction of Bayesian Deformable Models via Stochastic Approximation Algorithm: A Convergence Study

The problem of the definition and the estimation of generative models based on deformable templates from raw data is of particular importance for modelling non aligned data affected by various types of geometrical variability. This is especially true in shape modelling in the computer vision community or in probabilistic atlas building for Computational Anatomy (CA). A first coherent statistical framework modelling the geometrical variability as hidden variables has been given by Allassonni\`ere, Amit and Trouv\'e (JRSS 2006). Setting the problem in a Bayesian context they proved the consistency of the MAP estimator and provided a simple iterative deterministic algorithm with an EM flavour leading to some reasonable approximations of the MAP estimator under low noise conditions. In this paper we present a stochastic algorithm for approximating the MAP estimator in the spirit of the SAEM algorithm. We prove its convergence to a critical point of the observed likelihood with an illustration on images of handwritten digits

Shape deformation analysis from the optimal control viewpoint

A crucial problem in shape deformation analysis is to determine a deformation of a given shape into another one, which is optimal for a certain cost. It has a number of applications in particular in medical imaging. In this article we provide a new general approach to shape deformation analysis, within the framework of optimal control theory, in which a deformation is represented as the flow of diffeomorphisms generated by time-dependent vector fields. Using reproducing kernel Hilbert spaces of vector fields, the general shape deformation analysis problem is specified as an infinite-dimensional optimal control problem with state and control constraints. In this problem, the states are diffeomorphisms and the controls are vector fields, both of them being subject to some constraints. The functional to be minimized is the sum of a first term defined as geometric norm of the control (kinetic energy of the deformation) and of a data attachment term providing a geometric distance to the target shape. This point of view has several advantages. First, it allows one to model general constrained shape analysis problems, which opens new issues in this field. Second, using an extension of the Pontryagin maximum principle, one can characterize the optimal solutions of the shape deformation problem in a very general way as the solutions of constrained geodesic equations. Finally, recasting general algorithms of optimal control into shape analysis yields new efficient numerical methods in shape deformation analysis. Overall, the optimal control point of view unifies and generalizes different theoretical and numerical approaches to shape deformation problems, and also allows us to design new approaches. The optimal control problems that result from this construction are infinite dimensional and involve some constraints, and thus are nonstandard. In this article we also provide a rigorous and complete analysis of the infinite-dimensional shape space problem with constraints and of its finite-dimensional approximations

Multiple Shape Registration using Constrained Optimal Control

Lagrangian particle formulations of the large deformation diffeomorphic metric mapping algorithm (LDDMM) only allow for the study of a single shape. In this paper, we introduce and discuss both a theoretical and practical setting for the simultaneous study of multiple shapes that are either stitched to one another or slide along a submanifold. The method is described within the optimal control formalism, and optimality conditions are given, together with the equations that are needed to implement augmented Lagrangian methods. Experimental results are provided for stitched and sliding surfaces

Existence and Continuity of Minimizers for the Estimation of Growth Mapped Evolutions for Current Data Term and Couterexamples for Varifold Data Term

In the field of computational anatomy, the complexity of changes occurring during the evolution of a living shape while it is growing, aging or reacting to a disease, calls for more and more accurate models to allow subject comparison. Growth mapped evolutions have been introduced to tackle the loss of homology between two ages of an organism following a growth process that involves creation of new material. They model the evolution of longitudinal shape data with partial mappings. One viewpoint consists in a progressive embedding of the shape into an ambient space on which acts a group of diffeomorphisms. In practice, the shape evolves through a time-varying dynamic called the growth dynamic. The concept of shape space has now been widely studied and successfully applied to analyze the variability of a population of related shapes. Time-varying dynamics subsequently enlarge this framework and open the door to new optimal control problems for the assimilation of longitudinal shape data. We address in this paper an interesting problem in the field of the calculus of variations to investigate the existence and continuity of solutions for the registration of growth mapped evolutions with the growth dynamic. This theoretical question highlights the unexpected role of the data term grounded either on current or varifold representations. Indeed, in this new framework, the spatial regularity of a continuous scenario estimated from a temporal sequence of shapes with the growth dynamic depends on the temporal regularity of the deformation. Current metrics have the property to be more robust to this spatial regularity than varifold metrics. We will establish the existence and continuity of global minimizers for current data term and highlight two counterexamples for varifold data term

Croisements rêvés de l’Histoire et des Lettres : lecture du Sermon sur la chute de Rome

Jérôme Ferrari, né en 1968 à Fozzano en Corse, exerce le métier de professeur de philosophie avant de se faire romancier. Dans Le Sermon sur la chute de Rome, prix Goncourt 2012, il n’écrit pas un roman historique au sens usuel du terme : l’histoire individuelle prend le pas sur l’histoire collective. On effectue un parcours du vingtième siècle à travers la conscience obscurcie d’un personnage, Marcel Antonetti, né après 1918 et mort dans les années 1970. Son agonie est évoquée dans l’épilogu..

« Écoutez/r Voir » : de Michel Picard à Elsa Triolet et vice-versa

« Écoutez-voir » présente la particularité d’être le titre d’un roman et d’un article de théorie littéraire. J’essaierai, usant de ce prétexte, de croiser dans ce qui va suivre la réflexion générale et les suggestions nées de l’œuvre littéraire. Chronologiquement, c’est le roman qui est premier. Elsa Triolet le publie en 1968 ; on y perçoit l’écho du bouleversement esthétique introduit par le Nouveau Roman. Écoutez-voir forme un diptyque avec Le Grand Jamais qui date de 1965. Il se signale p..

Sed tamen effabor ! : autour du Malherbe de Francis Ponge

La parole occupe une place privilégiée dans la poétique de Francis Ponge. L’un de ses auteurs de prédilection, Lucrèce, écrit dans le De rerum natura : « Sed tamen effabor ! ». On retrouve cette citation latine, avec sa traduction : « Pourtant, je parlerai ! », dans « Nous, mots français », écrit de circonstance qui paraît en 1978. Pour Lucrèce comme pour Ponge, la parole apparaît à la fois suspecte et nécessaire, vitale même, selon la tournure exclamative. La décision de parler vient clore u..