Person Authentication by Fusing Face and Speech Information
vision Reference EPFL-CONF-82406 Record created on 2006-03-10, modified on 2017-05-10

title: Face authentication with Gabor information on deformable graphs
abstract: Elastic graph matching has been proposed as a practical implementation of dynamic link matching, which is a neural network with dynamically evolving links between a reference model and an input image. Each node of the graph contains features that characterize the neighborhood of its location in the image. The elastic graph matching usually consists of two consecutive steps, namely a matching with a rigid grid, followed by a deformation of the grid, which is actually the elastic part. The deformation step is introduced in order to allow for some deformation, rotation, and scaling of the object to be matched. This method is applied here to the authentication of human faces where candidates claim an identity that is to be checked. The matching error as originally suggested is not powerful enough to provide satisfying results in this case. We introduce an automatic weighting of the nodes according to their significance. We also explore the significance of the elastic deformation for an application of face-based person authentication. We compare performance results obtained with and without the second matching step. Results show that the deformation step slightly increases the performance, but has lower influence than the weighting of the nodes. The best results are obtained with the combination of both aspects. The results provided by the proposed method compare favorably with two methods that require a prior geometric face normalization, namely the synergetic and eigenface approaches.

title: Face Authentication Using Morphological Dynamic Link Architecture
abstract: A very attractive approach for face detection is based on multiresolution images (also known as mosaic images). Motivated by the simplicity of this approach, a rule-based face detection algorithm in frontal views is developed first. Second, a novel dynamic link architecture based on multiscale morphological dilation-erosion is proposed for face authentication. More specifically, a sparse grid is placed over the outcome of face detection stage for each person in a reference set. Subsequently, multiscale morphological operations are employed to yield a feature vector at each node of the grid and dynamic link matching is applied to verify the identity of each person from a test set. The first experimental results reported in this paper verify the superiority of the proposed method over the (standard) dynamic link matching that is based on Gabor wavelets.

title: Expert Conciliation for Multi Modal Person Authentication Systems by Bayesian Statistics
abstract: We present an algorithm functioning as a supervisor module in a multi expert decision making machine. It uses the Bayes theory in order to estimate the biases of individual expert opinions. These are then used to calibrate and conciliate expert opinions to one opinion. We present a framework for simulating decision strategies using expert opinions whose properties are easily modifiable. By using real data coming from a person authentication system using image and speech data we were able to confirm that the proposed supervisor improves the quality of individual expert decisions by reaching success rates of 99.5 %.

title: Symmetry based indexing of diatoms in an image database
abstract: We introduce several methods for symmetry detection and present results of their experimental evaluation on diatom images. The methods are based on distance lists, cyclic string matching, and gray level gradient direction histograms. From the experimental results it can be concluded that symmetry information is useful for various indexing tasks in image databases. Types of symmetry considered in this paper are rotational and reflectional symmetry of the shape as well as symmetry of the gray level distribution of the internal structure of objects. Using the symmetry based indexing scheme proposed, the effort for the subsequent task of diatom classification can significantly be reduced.

title: Experiences with an Emotional Sales Agent
abstract: With COSIMAB2B we demonstrate a prototype of a complex and visionary e-procurement application. The embodied character agent named COSIMA is able to respect a customer’s preferences and deals with him or her via natural speech. She expresses various emotions via mimic, gesture, combined with speech synthesis, and COSIMA is even able to consider the customer’s emotions via mimic recognition. As first observations show, this is a very promising approach to improve the bargaining with the customer or the recommendation of products.

title: Docking by Monte Carlo minimization with a solvation correction: Application to an FKBP - substrate complex
abstract: A Monte Carlo docking procedure that combines random displacements of the substrate and protein side chains with minimization of the enzyme]substrate complex is described and applied to finding the binding mode of the blocked tetrapeptide N-acetyl-Leu-Pro-Phe-methylamide to the FK506 binding protein Ž .  The tetrapeptide, an analog of the preferred FKBP substrate, and the FKBP binding site are flexible during the docking procedure. The twisted-imide transition-state form of the substrate is used during docking. The enzyme charges are scaled individually to account for solvent screening of specific binding site residues during the Monte Carlo sampling. To evaluate the relative binding free energies of the resulting structures, a rapid method for calculating polar and nonpolar solvation effects is introduced. Accurate electrostatic solute]solvent energies are calculated by solving the finite-difference linearized Poisson]Boltzmann equation; nonpolar contributions to the stability of the different conformers are estimated by the free energy of cavity formation, which is obtained from the molecular surface, and the solute]solvent van der Waals energy, which is calculated with a continuum approach. In the conformation of the enzyme]substrate complex with the lowest free energy, the tetrapeptide is bound as a type VIa proline turn with solvent accessible ends to permit longer polypeptide chains to act as substrates. Except for the imide carbonyl, which is involved in polar interactions with aromatic side chains of the FKBP binding *Present address: Pharmaceutical Research, F. Hoffmann]La Roche Ltd., CH-4070 Basel, Switzerland. Author to whom all correspondence should be addressed. ( 21 CAFLISCH, FISCHER, AND KARPLUS site, all of the seven potential hydrogen bond donors or acceptors of the tetrapeptide are satisfied. The FKBP binding site has a similar conformation in the substrate complex as in the FKBP-FK506 cocrystal structure, except for the predicted reorientation of the Tyr 82 hydroxyl, which plays an important role in substrate binding. The present model for the FKBP]substrate complex is in agreement with the recently determined crystal structure of a cyclic peptide]FK506 hybrid bound to FKBP and supports the structure obtained previously by iterative model building. In addition, it is consistent with the observed effects of FKBP point mutations on the enzyme activity. The approach described here should be useful, in general, for the prediction of the structure of a molecule in solution or as part of a complex. It provides for the effective sampling of conformational space and for the inclusion of solvent effects. Q 1997 by John Wiley & Sons, Inc.

title: Evaluation and optimization of the catalog search process of e-procurement platforms
abstract: With the emerging of e-catalog standards the product search can be used in a very different and improved matter. Beyond the usual keyword search this opens the arena for attribute-based search engines, including parametric search and preference search. We analyze the impact of different search techniques for such e-catalogs on the overall search process costs. It turns out that preference search has a high potential to significantly reduce the process costs. A large-scale use case with the MAN2B e-procurement platform supports our claim. We identify improvements achievable by using preference search, in particular less navigation steps during the product search and better search results due to the BMO query model. Expensive cases, where frustrated users accept bad search results or phone up the company's purchasing department, should decrease significantly. This in turn will enable the purchasing department to focus more on strategic issues like supplier relationship management than on operative issues as it still happens widely today.

title: Nonuniform charge scaling (NUCS): A practical approximation of solvent electrostatic screening in proteins
abstract: In molecular mechanics calculations, electrostatic interactions between chemical groups are usually represented by a Coulomb potential between the partial atomic charges of the groups. In aqueous solution these interactions are modified by the polarizable solvent. Although the electrostatic effects of the polarized solvent on the protein are well described by the Poisson--Boltzmann equation, its numerical solution is computationally expensive for large molecules such as proteins. The procedure of nonuniform charge scaling (NUCS) is a pragmatic approach to implicit solvation that approximates the solvent screening effect by individually scaling the partial charges on the explicit atoms of the macromolecule so as to reproduce electrostatic interaction energies obtained from an initial Poisson--Boltzmann analysis. Once the screening factors have been determined for a protein the scaled charges can be easily used in any molecular mechanics program that implements a Coulomb term. The approach is particularly suitable for minimization-based simulations, such as normal mode analysis, certain conformational reaction path or ligand binding techniques for which bulk solvent cannot be included explicitly, and for combined quantum mechanical/molecular mechanical calculations when the interface to more elaborate continuum solvent models is lacking. The method is illustrated using reaction path calculations of the Tyr 35 ring flip in the bovine pancreatic trypsin inhibitor.