1,720,982 research outputs found
Multiscale analysis of potential fields by a ridge consistency criterion: The reconstruction of the Bishop basement
No full textWe use a multiscale approach as a semi-automated interpreting tool of potential fields. The
depth to the source and the structural index are estimated in two steps: first the depth to the
source, as the intersection of the field ridges (lines built joining the extrema of the field at
various altitudes) and secondly, the structural index by the scale function.We introduce a new
criterion, called ‘ridge consistency’ in this strategy. The criterion is based on the principle
that the structural index estimations on all the ridges converging towards the same source
should be consistent. If these estimates are significantly different, field differentiation is used
to lessen the interference effects from nearby sources or regional fields, to obtain a consistent
set of estimates. In our multiscale framework, vertical differentiation is naturally joint to the
low-pass filtering properties of the upward continuation, so is a stable process. Before applying
our criterion, we studied carefully the errors on upward continuation caused by the finite size
of the survey area. To this end, we analysed the complex magnetic synthetic case, known as
Bishop model, and evaluated the best extrapolation algorithm and the optimal width of the
area extension, needed to obtain accurate upward continuation. Afterwards, we applied the
method to the depth estimation of the whole Bishop basement bathymetry. The result is a
good reconstruction of the complex basement and of the shape properties of the source at the
estimated points
Upward continuation and multilevel methods: tests on the Bishop5 model
No full textUpward continuation and multilevel SCALFUN potential field interpretation method are tested on a selected area of the Bishop 5 model corresponding to the South-Eastern intrusion. Insights in use of upward continuation and good depth estimation are obtained
Composite continuous wavelet transform of potential fields with different choices of analyzing wavelets
No full textIn potential field problems, the continuous wavelet transform (CWT) has allowed the estimation of the source properties, such as the depth to the source and the structural index (N). The natural choice for the analyzing wavelets has been the set belonging to the Poisson kernel. However, a much larger set of analyzing wavelets has been used for analyzing signals other than potential fields. Here we extend the CWT of potential fields to other wavelet families. Since the field is intrinsically dilated with Poissonian wavelets from the source depth to the measurement level, distortions are unavoidably introduced when CWT uses a different wavelet from the measurement level to other scales. To fix the problem, we define a new form for the continuous wavelet transform convolution product, called “composite continuous wavelet transform” (CCWT). CCWT removes the field dilations with Poisson wavelets, intrinsically contained at the measurement level and replaces them with dilations performed with any other kind of wavelet. The method is applied to synthetic and real cases, involving sources as poles, dipoles, intrusions in complex magnetized basement topography and buried steel drums, from measurements taken at the Stanford University test site. CCWT takes advantage from the special features of the several considered wavelets, e.g., the Gaussian wavelet is useful for its low pass filtering characteristic and Morlet wavelet for its localization property. Hence, depending on the case, an important parameter for the choice of the analyzing wavelet is its central frequency
Continuous wavelet transform of potential fields with different choices of analyzing wavelets
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Waiting for Tactile: Robotic and Virtual Experiences in the Fog
No full textSocial robots adopt an emotional touch to interact with users inducing and transmitting humanlike emotions. Natural interaction with humans needs to be in real time and well grounded on the full availability of information on the environment. These robots base their way of communicating on direct interaction (touch, listening, view), supported by a range of sensors on the surrounding environment that provide a radially central and partial knowledge on it. Over the past few years, social robots have been demonstrated to implement different features, going from biometric applications to the fusion of machine learning environmental information collected on the edge. This article aims at describing the experiences performed and still ongoing and characterizes a simulation environment developed for the social robot Pepper that aims to foresee the new scenarios and benefits that tactile connectivity will enable
Demographic classification through pupil analysis
Full text linkAn area of biometrics that has recently attracted much attention is gender and age classification. Its applications can be found not only in the fields of security and surveillance, but also in the context of marketing and demographic information gathering. In addition, extracting this information from a biometric sample can help to decrease the time to identify the exact individual. In this paper, we exploit pupil size as a discriminating feature for the estimation of gender and age. Data obtained from the free observation of face images have been used to train two classifiers (Adaboost and SVM), considering both the best results produced by each classifier and their fusion through weighted means. With experiments involving more than 100 participants, we have found that pupil size can provide significant results, better than those achievable using data on fixations and gaze paths. Pupil Diameter Mean (PDM) has proved to be the best discriminating feature for both gender and age. To the best of our knowledge, there are no other studies trying to perform such a classification using pupil size only
- …
