Search results for "Graph theory"
showing 10 items of 784 documents
Searching events in AFM force-extension curves: A wavelet approach
2016
An algorithm, based on the wavelet scalogram energy, for automatically detecting events in force-extension AFM force spectroscopy experiments is introduced. The events to be detected are characterized by a discontinuity in the signal. It is shown how the wavelet scalogram energy has different decay rates at different points depending on the degree of regularity of the signal, showing faster decay rates at regular points and slower rates at singular points (jumps). It is shown that these differences produce peaks in the scalogram energy plot at the event points. Finally, the algorithm is illustrated in a tether analysis experiment by using it for the detection of events in the AFM force-exte…
Automatic monitoring system for the detection and evaluation of the evolution of hemangiomas
2016
In this paper we introduce an automatic monitoring system for the detection and the evaluation of the evolution of hemangiomas using a fuzzy logic system based on two parameters: area and redness. We have considered pairs of images (from two different moments in time) that show hemangiomas either evolving, stationary or regressing. The starting points of the algorithm are the rectangular regions of interest (ROI), manually selected for each of the two images, and automatically segmented using Fuzzy C-means. Using the area and the redness of the hemagiomas extracted with Fuzzy C-means, for the same patient, at different moments of time, the algorithm decides whether the hemangioma is evolvin…
The Metabolic Building Blocks of a Minimal Cell
2020
This article belongs to the Section Evolutionary Biology.
Generalized Molecular Descriptors Derived From Event-Based Discrete Derivative.
2016
In the present study, a generalized approach for molecular structure characterization is introduced, based on the relation frequency matrix (F) representation of the molecular graph and the subsequent calculation of the corresponding discrete derivative (finite difference) over a pair of elements (atoms). In earlier publications (22- 24), an unique event, named connected subgraphs, (based on the Kier-Hall's subgraphs) was systematically employed for the computation of the matrix F. The present report is a generalization of this notion, in which eleven additional events are introduced, classified in three categories, namely, topological (terminal paths, vertex path incidence, quantum subgrap…
2019
Background: Network science provides powerful access to essential organizational principles of the brain. The aim of this study was to investigate longitudinal evolution of gray matter networks in early relapsing–remitting MS (RRMS) compared with healthy controls (HCs) and contrast network dynamics with conventional atrophy measurements. Methods: For our longitudinal study, we investigated structural cortical networks over 1 year derived from 3T MRI in 203 individuals (92 early RRMS patients with mean disease duration of 12.1 ± 14.5 months and 101 HCs). Brain networks were computed based on cortical thickness inter-regional correlations and fed into graph theoretical analysis. Network conne…
In.Line: A Navigation Game for Visually Impaired People
2017
Part 3: Serious Games; International audience; In.line is a novel game based on a navigation system, called ARIANNA (pAth Recognition for Indoor Assisted NavigatioN with Augmented perception, [1]), primarily designed for visually impaired people permitting to navigate and find some points of interests in an indoor and outdoor environment by following a path painted or stuck on the floor. The aim of the game is twofold: (1) let the users learn and familiarize with the system, (2) improve blind people spatial skills to let them learn and acquire an allocentric spatial representation. The impact stands in the possibility of enhancing the social inclusion of a large part of the society that is …
Efficient Online Laplacian Eigenmap Computation for Dimensionality Reduction in Molecular Phylogeny via Optimisation on the Sphere
2019
Reconstructing the phylogeny of large groups of large divergent genomes remains a difficult problem to solve, whatever the methods considered. Methods based on distance matrices are blocked due to the calculation of these matrices that is impossible in practice, when Bayesian inference or maximum likelihood methods presuppose multiple alignment of the genomes, which is itself difficult to achieve if precision is required. In this paper, we propose to calculate new distances for randomly selected couples of species over iterations, and then to map the biological sequences in a space of small dimension based on the partial knowledge of this genome similarity matrix. This mapping is then used …
An optimal population code for global motion estimation in local direction-selective cells
2021
AbstractNervous systems allocate computational resources to match stimulus statistics. However, the physical information that needs to be processed depends on the animal’s own behavior. For example, visual motion patterns induced by self-motion provide essential information for navigation. How behavioral constraints affect neural processing is not known. Here we show that, at the population level, local direction-selective T4/T5 neurons in Drosophila represent optic flow fields generated by self-motion, reminiscent to a population code in retinal ganglion cells in vertebrates. Whereas in vertebrates four different cell types encode different optic flow fields, the four uniformly tuned T4/T5…
Exogenous sources of regional industrial change
2017
The role of exogenous sources of new path development has been underplayed in the literature on regional industrial change so far. The aim of this article is to explore in a conceptual way under which conditions and in what ways non-local knowledge can lead to new path development in different regional innovation systems (RISs). We distinguish between organizationally thick and diversified RISs, thick and specialized RISs and thin RISs and argue that these types vary substantially in their needs for exogenous sources as well as in their capacities to attract and absorb knowledge generated elsewhere.
Autonomous vehicle with communicative driving for pedestrian crossing: Trajectory optimization
2020
Connected and autonomous vehicles (CAV) is a key technology for this century. One of the main challenges is to define a smart interaction behavior of CAV with the other road users. The challenge is mainly raised at conflicting points where path of CAV intersects with the other users. Recent studies show interaction with humans is a big challenge. It not only requires a collision avoidance system but also more communicative behaviors of the CAV. More precisely, pedestrian needs to understand the intention of the incoming CAV whether it will cross first or not according to its speed profile. One way to overcome this issue is to design optimal trajectory control of the CAV that matches with th…