Feature Point Detection and Curve Approximation for Early Processing of Freehand Sketches

Freehand sketching is both a natural and crucial part of design, yet is unsupported by current design automation software. We are working to combine the flexibility and ease of use of paper and pencil with the processing power of a computer to produce a design environment that feels as natural as paper, yet is considerably smarter. One of the most basic steps in accomplishing this is converting the original digitized pen strokes in the sketch into the intended geometric objects using feature point detection and approximation. We demonstrate how multiple sources of information can be combined for feature detection in strokes and apply this technique using two approaches to signal processing, one using simple average based thresholding and a second using scale space.

Verb Classes and Alternations in Bangla, German, English, and Korean

In this report, we investigate the relationship between the semantic and syntactic properties of verbs. Our work is based on the English Verb Classes and Alternations of (Levin, 1993). We explore how these classes are manifested in other languages, in particular, in Bangla, German, and Korean. Our report includes a survey and classification of several hundred verbs from these languages into the cross-linguistic equivalents of Levin's classes. We also explore ways in which our findings may be used to enhance WordNet in two ways: making the English syntactic information of WordNet more fine-grained, and making WordNet multilingual.

Priors Stabilizers and Basis Functions: From Regularization to Radial, Tensor and Additive Splines

We had previously shown that regularization principles lead to approximation schemes, as Radial Basis Functions, which are equivalent to networks with one layer of hidden units, called Regularization Networks. In this paper we show that regularization networks encompass a much broader range of approximation schemes, including many of the popular general additive models, Breiman's hinge functions and some forms of Projection Pursuit Regression. In the probabilistic interpretation of regularization, the different classes of basis functions correspond to different classes of prior probabilities on the approximating function spaces, and therefore to different types of smoothness assumptions. In the final part of the paper, we also show a relation between activation functions of the Gaussian and sigmoidal type.

The Individual is Nothing, the Class Everything: Psychophysics and Modeling of Recognition in Obect Classes

Most psychophysical studies of object recognition have focussed on the recognition and representation of individual objects subjects had previously explicitely been trained on. Correspondingly, modeling studies have often employed a 'grandmother'-type representation where the objects to be recognized were represented by individual units. However, objects in the natural world are commonly members of a class containing a number of visually similar objects, such as faces, for which physiology studies have provided support for a representation based on a sparse population code, which permits generalization from the learned exemplars to novel objects of that class. In this paper, we present results from psychophysical and modeling studies intended to investigate object recognition in natural ('continuous') object classes. In two experiments, subjects were trained to perform subordinate level discrimination in a continuous object class - images of computer-rendered cars - created using a 3D morphing system. By comparing the recognition performance of trained and untrained subjects we could estimate the effects of viewpoint-specific training and infer properties of the object class-specific representation learned as a result of training. We then compared the experimental findings to simulations, building on our recently presented HMAX model of object recognition in cortex, to investigate the computational properties of a population-based object class representation as outlined above. We find experimental evidence, supported by modeling results, that training builds a viewpoint- and class-specific representation that supplements a pre-existing repre-sentation with lower shape discriminability but possibly greater viewpoint invariance.

Sparse Representations of Multiple Signals

We discuss the problem of finding sparse representations of a class of signals. We formalize the problem and prove it is NP-complete both in the case of a single signal and that of multiple ones. Next we develop a simple approximation method to the problem and we show experimental results using artificially generated signals. Furthermore,we use our approximation method to find sparse representations of classes of real signals, specifically of images of pedestrians. We discuss the relation between our formulation of the sparsity problem and the problem of finding representations of objects that are compact and appropriate for detection and classification.

An Equivalence Between Sparse Approximation and Support Vector Machines

In the first part of this paper we show a similarity between the principle of Structural Risk Minimization Principle (SRM) (Vapnik, 1982) and the idea of Sparse Approximation, as defined in (Chen, Donoho and Saunders, 1995) and Olshausen and Field (1996). Then we focus on two specific (approximate) implementations of SRM and Sparse Approximation, which have been used to solve the problem of function approximation. For SRM we consider the Support Vector Machine technique proposed by V. Vapnik and his team at AT&T Bell Labs, and for Sparse Approximation we consider a modification of the Basis Pursuit De-Noising algorithm proposed by Chen, Donoho and Saunders (1995). We show that, under certain conditions, these two techniques are equivalent: they give the same solution and they require the solution of the same quadratic programming problem.

Convergence Rates of Approximation by Translates

In this paper we consider the problem of approximating a function belonging to some funtion space Φ by a linear comination of n translates of a given function G. Ussing a lemma by Jones (1990) and Barron (1991) we show that it is possible to define function spaces and functions G for which the rate of convergence to zero of the erro is 0(1/n) in any number of dimensions. The apparent avoidance of the "curse of dimensionality" is due to the fact that these function spaces are more and more constrained as the dimension increases. Examples include spaces of the Sobolev tpe, in which the number of weak derivatives is required to be larger than the number of dimensions. We give results both for approximation in the L2 norm and in the Lc norm. The interesting feature of these results is that, thanks to the constructive nature of Jones" and Barron"s lemma, an iterative procedure is defined that can achieve this rate.

Ús de minicasos a les classes expositives de psicologia

L’assoliment de l’Espai Europeu d’Educació Superior implica nous rols per a professors i alumnes i la introducció de noves metodologies docents. En aquest article es presenta una experiència d’innovació en la docència de la Psicologia consistent en la incorporació de minicasos a les classes expositives de l’assignatura troncal i anual “Avaluació Psicològica” de segon curs de la llicenciatura de Psicologia. S’exposa el procediment i s’analitza l’opinió dels estudiants respecte a la utilitats dels minicasos per incrementar l’atenció, l’interès i la comprensió de l’assignatura

A First approximation to the realism/idealism debate about the external world

El text intenta fer una primera aproximació al debat contemporani entre realistes i anti-realistes sobre el món empíric, centrant-se en les posicions de Putnam i Nagel. El seu objectiu principal és el d'entendre les motivacions de les posicions i l'estructura actual del debat, i el d'establir les característiques que hauria de tenir qualsevol posició satisfactòria

Admission Control for TCP Flows Using Packet Classes and Edge-to-edge Measurements of Aggregates

TCP flows from applications such as the web or ftp are well supported by a Guaranteed Minimum Throughput Service (GMTS), which provides a minimum network throughput to the flow and, if possible, an extra throughput. We propose a scheme for a GMTS using Admission Control (AC) that is able to provide different minimum throughput to different users and that is suitable for "standard" TCP flows. Moreover, we consider a multidomain scenario where the scheme is used in one of the domains, and we propose some mechanisms for the interconnection with neighbor domains. The whole scheme uses a small set of packet classes in a core-stateless network where each class has a different discarding priority in queues assigned to it. The AC method involves only edge nodes and uses a special probing packet flow (marked as the highest discarding priority class) that is sent continuously from ingress to egress through a path. The available throughput in the path is obtained at the egress using measurements of flow aggregates, and then it is sent back to the ingress. At the ingress each flow is detected using an implicit way and then it is admission controlled. If it is accepted, it receives the GMTS and its packets are marked as the lowest discarding priority classes; otherwise, it receives a best-effort service. The scheme is evaluated through simulation in a simple "bottleneck" topology using different traffic loads consisting of "standard" TCP flows that carry files of varying sizes

Ideologia, política i llenguatge de classes en el primer sindicalisme, 1840-1870

Estudi del sindicalisme a Espanya des dels seus orígens i fins el 1870. L’autor planteja dues qüestions: la ideologia elaborada pel sindicalisme entre 1840 i 1856, i en segon lloc alguns aspectes de les relacions entre sindicalisme i política, i l’elaboració d’un llenguatge de classes

JavaScript Prototypes, Objects and Classes

The full story on the JavaScript object model, and how prototypes are used instead of classes

El que pensa l'alumnat d'educació secundària sobre les classes d'educació física i no gosa dir-li al professor_a.

Se muestran tablas y gráficas de los resultados obtenidos. Resumen tomado del autor. En el título hay una barra inclinada entre professor y a

Apropar les classes de biologia als debats més actuals : a tall de mostra, els parcs naturals. 'Acercar las clases de biología a los debates más actuales : como muestra, los parques naturales'.

La enseñanza de las ciencias se puede realizar mediante diversas aproximaciones pero el enorme contenido conceptual y cierta actitud de inercia hacen que esta enseñanza a menudo se aleje de la realidad. En los últimos años se ha avanzado especialmente en la significacion de los contenidos para el alumnado y en el tratamiento de las cuestiones más candentes y controvertidas de la sociedad actual. Una buena muestra es el estudio del concepto de parque natural para poder usar algunos recursos educativos. Se aborda el caso de los espacios naturales protegidos en las islas Baleares, su evolución histórica y las tendencias actuales. Finalmente se incluyen algunas propuestas pedagógicas y se aconsejan algunas páginas web.

Estratègies per augmentar el temps de pràctica motriu en les classes d'educació física escolar. 'Estrategias para aumentar el tiempo de práctica motriz en las clases de educación física escolar'.

El análisis de la práctica diaria muestra los escasos minutos con que cuenta el alumno para practicar y poder conseguir los objetivos marcados. Este artículo trata de presentar una serie de recursos y estrategias que ayuden al profesor de educación física a reducir el tiempo dedicado a la presentación y organización de las actividades que se proponen en clase, con la finalidad de arañar minutos en beneficio del tiempo de práctica, esencial para el aprendizaje. Por ello, y al revisar algunas de las más destacadas fuentes bibliográficas que tratan sobre el tema, se analizan los distintos tiempos que existen en la sesión de educación física y se estudian las acciones y variables que pueden restar minutos al tiempo de la práctica motriz. Finalmente se presentan una serie de estrategias y recursos metodológicos en relación a los distintos bloques del contenido del currículum que permiten a los profesores dedicar más tiempo a las tareas de aprendizaje. l resumen es traducción del publicado con el artículo.