Archive

We possess a wealth of prior knowledge about most prediction problems, and particularly so for many of the fundamental tasks in natural language processing. Unfortunately, it is often difficult to make use of this type of information during learning, as it typically does not come in the form of labeled examples, may be difficult to encode as a prior on parameters in a Bayesian setting,...

Inductive Logic Programming (ILP) is a Machine Learning approach with foundations in Logic Programming. The problem specification and the models discovered by ILP systems are both represented as Prolog programs allowing for great expressiveness and flexibility. However, this flexibility comes at a high computational cost and ILP systems are known for their difficulty in scaling-up. Constructing and evaluating complex concepts are two of the main...

In the first half of the talk, I will give an overview on structured prediction, a general framework which encompasses many learning formalisms, such as those underlying hidden Markov models, conditional random fields, and structured support vector machines. Applications abound in natural language processing, computer vision, and computational biology. In the second half, I will focus on approximate MAP inference in discrete graphical models. I...

Designing a component, process or a control system to achieve minimum or maximum of a single objective (or goal) often results in a single optimum solution describing the shape, dimensions, process or strategy of solving the task. Although such an optimized solution may already provide a new and innovative way of achieving the best objective value, it is almost never the case that practitioners are...

The electrocardiographic (ECG) signal has been shown to contain relevant information for human identification. Even though results validate the potential of these signals, data acquisition methods and apparatus explored so far compromise user acceptability, requiring the acquisition of ECG at the chest. In this talk we review the state of the art on using ECG as biometric trait. We present a finger based ECG biometric...

Surveillance systems aim to characterize human activities and to detect abnormal behaviors. This task is specially challenging if the camera field of view is wide and the objects are far from the camera. In such operating conditions, it is not possible to extract detailed descriptions of the objects such as shape and color. In this case, most of the information is conveyed by the object trajectory...

In many applications, we deal with high dimensional datasets with sparse data (many features have zero value with high probability). For instance, in text classification and information retrieval problems, we have large collections of documents. Each text is usually represented by a bag-of-words or similar representation, with a large number of features (terms). Many of these features may be irrelevant (or even detrimental) for the...

Genetic Programming (GP) is the youngest paradigm inside the Artificial Intelligence field called Evolutionary Computation. Created by John Koza in 1992, it can be regarded as a powerful generalization of Genetic Algorithms, but unfortunately it is still poorly understood outside the GP community. The goal of this tutorial is to provide motivation, intuition and practical advice about GP, along with very few technical details....

The thesis addresses two important nonlinear inverse problems in image processing: the separation of show-through and the bleed-trough mixtures and the blind deblurring of images. New solutions to cope with their high levels of indetermination are proposed. Two separation methods are developed for the first problem. In a first approach, the indeterminacy of nonlinear Independent Component Analysis (ICA) is reduced through the use of a physical...

Numerous signals arising from physiological and physical processes are not only non-stationary but also posses a mixture of sustained oscillations and non-oscillatory transients that are difficult to disentangle by linear methods. Examples of such signals include speech, biomedical and geophysical signals. This talk describes the decomposition of such signals into 'resonance' components: A high-resonance signal is one in which oscillations are sustained; while a low-resonance...