Search results for "Descriptor"

Virtual lock and key approach: the revival of Fischer model

2009

Quantitative descriptors in myopic eyes

2020

La prevalencia de la miopía ha demostrado ser mayor entre la población con una educación superior. Se cree que el tiempo dedicado a actividades de trabajo cercano tiene un papel en dicha asociación entre la miopía y el nivel educativo alcanzado. De hecho, el tiempo dedicado al trabajo cercano y su intensidad, especialmente la lectura continua, han demostrado aumentar las probabilidades de miopía en niños. Los estudiantes universitarios constituyen un grupo de población joven expuesto a mucho trabajo cercano prolongado por lo que que tiene un riesgo especial de desarrollo y progresión de la miopía durante sus estudios. Esta investigación tuvo como objetivo caracterizar el ojo miope mediante …

A statistical model for magnitudes and angles of wavelet frame coefficients and its application to texture retrieval

2014

Abstract This paper presents a texture descriptor based on wavelet frame transforms. At each position in the image, and for each resolution level, we consider both vertical and horizontal wavelet detail coefficients as the components of a bivariate random vector. The magnitudes and angles of these vectors are computed. At each level the empirical histogram of magnitudes is modeled by a Generalized Gamma distribution, and the empirical histogram of angles is modeled by a different version of the von Mises distribution that accounts for histograms with 2 modes. Each texture is characterized by few parameters. A new distance is presented (based on the Kullback–Leibler divergence) that allows g…

Advanced descriptors for long-range noncovalent interactions between SARS-CoV-2 spikes and polymer surfaces.

2021

The recent pandemic triggered numerous societal efforts aimed to control and limit the spread of SARS-CoV-2. One of these aspects is related on how the virion interacts with inanimate surfaces, which might be the source of secondary infection. Although recent works address the adsorption of the spike protein on surfaces, there is no information concerning the long-range interactions between spike and surfaces, experimented by the virion when is dispersed in the droplet before its possible adsorption. Some descriptors, namely the interaction potentials per single protein and global potentials, were calculated in this work. These descriptors, evaluated for the closed and open states of the sp…

IMAGE ORIENTATION WITH A HYBRID PIPELINE ROBUST TO ROTATIONS AND WIDE-BASELINES

2022

Abstract. The extraction of reliable and repeatable interest points among images is a fundamental step for automatic image orientation (Structure-From-Motion). Despite recent progresses, open issues in challenging conditions - such as wide baselines and strong light variations - are still present. Over the years, traditional hand-crafted methods have been paired by learning-based approaches, progressively updating the state-of-the-art according to recent benchmarks. Notwithstanding these advancements, learning-based methods are often not suitable for real photogrammetric surveys due to their lack of rotation invariance, a fundamental requirement for these specific applications. This paper p…

Characterizing Cavities in Model Inclusion Fullerenes: A Comparative Study

2001

Abstract: The fullerene-82 cavity is selected as a model system in order to test several methods for characterizing inclusion molecules. The methods are based on different technical foundations such as a square and triangular tessellation of the molecular surface, spherical tessellation of the molecular surface, numerical integration of the atomic volumes and surfaces, triangular tessellation of the molecular surface, and cubic lattice approach to the molecular volume. Accurate measures of the molecular volume and surface area have been performed with the pseudorandom Monte Carlo (MCVS) and uniform Monte Carlo (UMCVS) methods. These calculations serve as a reference for the rest of the meth…

Relationship between authors’ keywords in journal papers and indexing terms in databases ISOC, IME and ICYT

2005

The keywords provided by authors in their scientific articles and the descriptors assigned to those articles in various databases are analysed to find out the role played by these keywords during the indexing process. In order to do that, 108 periodical publications proportionally distributed between Social Sciences and Humanities (36 journals), Science and Technology (36) and Medical and Health Sciences (36) were selected. Ten articles were selected from each of the 108 journals from different years, so that we worked altogether on 1080 articles meeting two conditions: including keywords and being indexed in the databases ISOC, ICYT or IME. Then, we proceeded to draw a comparison between t…

QUALITY ASSURANCE IN PREUNIVERSITY ROMANIAN EDUCATION WITHIN THE EU INTEGRATION

2013

The Purpose of this work is to show the importance of quality assurance in Romanian pre-university education. The research objectives are:identification of quality performance descriptors of Romanian pre-university education,identify performance improvement indicators as Research methodology is documented by capturing the qualitative analysis. The results of the research led to the understanding of the extent to which quality Romanian preuniversity education management is, compared to Europe.

SIFT Texture Description for Understanding Breast Ultrasound Images

2014

Texture is a powerful cue for describing structures that show a high degree of similarity in their image intensity patterns. This paper describes the use of Self-Invariant Feature Transform (SIFT), both as low-level and high-level descriptors, applied to differentiate the tissues present in breast US images. For the low-level texture descriptors case, SIFT descriptors are extracted from a regular grid. The high-level texture descriptor is build as a Bag-of-Features (BoF) of SIFT descriptors. Experimental results are provided showing the validity of the proposed approach for describing the tissues in breast US images.

Underwater archaeological mosaicing

2006

Archaeological mosaicing is one of the challenges of the computer vision community and it can be faced in a 2D or 3D approach. This contribution regards a methodology to do a mosaic of an underwater bi-dimensional scene. A number of problems arise from the acquisition of images by a remote operated vehicle. Radial distortion, poor luminosity, cloud water, presence of artefacts are part of the issues that can occur; for instance, the radial distortion has been corrected to improve the quality of the input images. Keypoints detection (through SIFT transform), Singular Value Decomposition, Random Samples Consensus are some of the techniques applied in our method. This contribution regards the …