The convergent correlator is widely used but it presents the drawback of the alignment requirements: fine focusing of the input scene Fourier transform on the filter plane, filter centering, scaling the scene Fourier transform to match the filter size, and azimuth matching of the filter with the input scene. We propose a set of tests to obtain a precise alignment of the convergent correlator. These methods are based on frequency filtering properties and they are applicable either for amplitude input or for phase-encoded input. The tests we present allow us to fulfill all the alignment requirements. The theory on which these tests are based is explained. The experimental results obtained during the alignment procedure are presented. We show some additional verifications of the correct alignment of the convergent correlator. 相似文献
Program slicing is a well-known technique to extract the program statements that (potentially) affect the values computed at some point of interest. In this work, we introduce a novel slicing method for XML documents. Essentially, given an XML document (which is valid w.r.t. some DTD), we produce a new XML document (a slice) that contains the relevant information in the original XML document according to some criterion. Furthermore, we also output a new DTD such that the computed slice is valid w.r.t. this DTD. A prototype implementation of the XML slicer has been undertaken. 相似文献
An image can be seen as an element of a vector space and hence it can be expressed in as a linear combination of the elements
of any non necessarily orthogonal basis of this space. After giving a matrix formulation of this well-known fact, this paper
presents a reconstruction method of an image from its moments that sheds new light on this inverse problem. Two main contributions
are presented: (a) the results using the standard approach based on the least squares approximation of the result using orthogonal
polynomials can also be obtained using matrix pseudoinverses, which implies higher control on the numerical stability of the
problem; and (b) it is possible to use basis functions in the reconstruction different from orthogonal polynomials, such as
Fourier or Haar basis, allowing to introduce constraints relative to the bandwidth or the spatial resolution on the image
to be reconstructed.
Judit Martònez received the B.Sc. degree in 1993 and the PhD degree (with honors) in 1998, both in telecommunications engineering from the
Technical University of Catalonia. She developed her research at the Institut de Robútica i Informütica Industrial of the
Spanish High Council for Scientific Research. In 1999 she joined the Computer Vision Center, a R&D center founded by the Autonomous
University of Barcelona and the Autonomous Government of Catalonia. She has been principal researcher of several industrial
and research projects related to computer vision technologies. Her research interests include industrial applications of machine
vision, efficient algorithms for low-level image processing, multiresolution mathematical models, statistical clustering,
pattern classification and inverse problems.
Josep M. Porta received the Engineer Degree in Computer Science in 1994 and the Ph.D. in Artificial Intelligence in 2001, both from the
Technical University of Catalonia (UPC). After that, he joined the IAS group of the University of Amsterdam and currently,
he holds a post-doc position at the Institut de Robútica i Informütica Industrial (CSIC-UPC) in Barcelona. He carried research
in legged robots, machine learning, vision-based methods for autonomous robot localization, and computational kinematics.
Federico Thomas is Research Professor at the Spanish Scientific Research Council (CSIC) and director of the Institut de Robútica i Informütica
Industrial (CSIC-UPC), Barcelona, Spain. He received the telecommunications engineering degree in 1984, and the Ph.D. degree
(with honors) in computer science in 1988, both from the Technical University of Catalonia (UPC). In 1991, he won a NATO postdoctoral
scholarship at the University of Massachusetts with the late Prof. Robin Popplestone. In 1999, he was visiting professor,
sponsored by the Autonomous Government of Catalonia, at the Oxford University Computing Laboratory with Prof. Stephen Cameron.
He has been project leader of several national projects financed by the Spanish Committee for Science and Technology (CICYT),
and by local companies such as ENHER, a power generation company now part of ENDESA.
His current research interests are in Geometry and Kinematics with applications to Robotics, Computer Graphics and Computer
Vision. Prof. Thomas is an Associate Editor of the IEEE Transactions on Robotics. 相似文献
Brain activity recorded noninvasively is sufficient to control a mobile robot if advanced robotics is used in combination with asynchronous electroencephalogram (EEG) analysis and machine learning techniques. Until now brain-actuated control has mainly relied on implanted electrodes, since EEG-based systems have been considered too slow for controlling rapid and complex sequences of movements. We show that two human subjects successfully moved a robot between several rooms by mental control only, using an EEG-based brain-machine interface that recognized three mental states. Mental control was comparable to manual control on the same task with a performance ratio of 0.74. 相似文献
The aim of our study consists of contributing information on the relationship between the personality variables derived from Gray’s model and the conduct that accompanies the infringement of the road traffic rules. Seven hundred and ninety-two adults of both sexes took part in the study (389 men and 403 women), all of whom had driving licences and drove frequently. The subjects answered “The Sensitivity to Punishment and Sensitivity to Reward Questionnaire”, a scale of monotony avoidance, and two Likert scales of attitude and behaviour in connection with traffic violations.
We found a high positive relationship between attitude and behaviour, with the men infringing the rules more than the women. Hypotheses regarding a relationship between traffic offences and sensibility to reward and monotony avoidance were confirmed. Those people with high scores in sensitivity to punishment and low ones in sensitivity to reward were those who drove within the law, while those with low sensitivity to punishment and high sensitivity to reward were those who broke it more. Sensitivity to reward was a stronger determinant in encouraging infringement of the rules than was sensitivity to punishment in discouraging the subjects to do so. 相似文献
The easy detection of biomolecular interactions in complex mixtures using a minimum amount of material is of prime interest in molecular and cellular biology research. In this work, a mass spectrometry MALDI-TOF based approach, which we call intensity-fading (IF MALDI-TOFMS), and which was designed for just such a purpose, is reported. This methodology is based on the use of the MALDI ion intensities to detect quickly the formation of complexes between nonimmobilized biomolecules in which a protein is one of the partners (protein-protein, protein-peptide, protein-organic molecule, and protein-nucleic acid complexes). The complex is detected through the decrease (fading) of the molecular ion intensities of the partners as directly compared to the MALDI mass spectrum of the mixture (problem and control molecules) following the addition of the target molecule. The potential of the approach is examined in several examples of model interactions, mainly involving small nonprotein and protein inhibitors of proteases, at both the qualitative and semiquantitative levels. Using this method, different protein ligands of proteolytic enzymes in total extracts of invertebrate organisms have been identified in a simple way. The proposed procedure should be easily applied to the high-throughput screening of biomolecules, opening a new experimental strategy in functional proteomics. 相似文献
High silicon content aluminum alloy (hypereutectic) possess good tribological characteristics with low coefficients of friction, when embedded with short carbon fiber (Csf), making this composite a good material choice where good wear and high strength properties are required in light weight components. There is no previously published information available, to the knowledge of the authors, regarding the influence of wear parameters and their interactions on the tribological behavior of Csf reinforced metal matrix composites. In this study a Taguchi design of experiment (DoE) was conducted to optimize and analyze the effects of the wear parameters on the tribological properties of Al/Csf metal matrix composite. A novel thixomixing method which was used to process the metal within the semisolid state was employed to embed short carbon fibers homogenously into the metal matrix. The influences of the sliding speed, applied load and volume fraction, of Csf on the specific wear rate and coefficient of friction were examined, with each of these input parameters tested at three levels(0, 4.2, 8.1%vol.). The results were indicated that Al/Csf composite had better tribological properties than Al alloy due to which contains carbon as solid lubricant. According to the statistical analysis, the influence of volume fraction of carbon fiber on wear parameters was ranked first; so the load and sliding speed are at the following rankings. The contribution percentage for each parameter was determined by the analysis of variance. The relatively good interfacial adherence of carbon fiber and matrix alloy were demonstrated. The coherent and adherent graphite-rich layer on the worn surface was characterized using scanning electron microscopy (SEM). 相似文献
This paper introduces local distance-based generalized linear models. These models extend (weighted) distance-based linear models first to the generalized linear model framework. Then, a nonparametric version of these models is proposed by means of local fitting. Distances between individuals are the only predictor information needed to fit these models. Therefore, they are applicable, among others, to mixed (qualitative and quantitative) explanatory variables or when the regressor is of functional type. An implementation is provided by the R package dbstats, which also implements other distance-based prediction methods. Supplementary material for this article is available online, which reproduces all the results of this article. 相似文献