Search results for "A* algorithm"
showing 10 items of 2538 documents
Development of an imaging system dedicated to the acquisition analysis and multispectral characterisation of skin lesion
2011
Visual evaluation of cutaneous lesions is the analysis the most commonly performedby dermatologists. This diagnostic is mainly done by naked eye and is based on criterionsuch as the size, shape, symmetry but principally on colour of the lesions. However, thisanalysis is subjective because it depends on the practician experience and the acquisitionconditions. We propose in this dissertation (1) the development of a multispectralcamera specifically dedicated for dermatological use. This device is based on a filterwheel composed of interferential filters and a neural network-based algorithm, generatinga hyperspectral cube of cutaneous data. This setting combines advantage of both spectrophotom…
Metal speciation in solid matrices
1994
The literature on metal ion speciation in solid matrices is reviewed, taking into account its applications in the analysis of soil, sediment, biological materials, foodstuff and other solid samples. The pretreatment methods of various solid materials required for carrying out speciation studies have been highlighted. The basis of the methods of separation of different species from matrices, such as sequential extraction, selective extraction, etc. is discussed. The instrumental techniques used for the characterization of different chemical species in solid matrices have been mentioned. The literature survey reveals the analytical details of the developed methodologies, and these have been e…
The Effective Sample Size
2013
Model selection procedures often depend explicitly on the sample size n of the experiment. One example is the Bayesian information criterion (BIC) criterion and another is the use of Zellner–Siow priors in Bayesian model selection. Sample size is well-defined if one has i.i.d real observations, but is not well-defined for vector observations or in non-i.i.d. settings; extensions of critera such as BIC to such settings thus requires a definition of effective sample size that applies also in such cases. A definition of effective sample size that applies to fairly general linear models is proposed and illustrated in a variety of situations. The definition is also used to propose a suitable ‘sc…
Hidden Markov random field model and Broyden–Fletcher–Goldfarb–Shanno algorithm for brain image segmentation
2018
International audience; Many routine medical examinations produce images of patients suffering from various pathologies. With the huge number of medical images, the manual analysis and interpretation became a tedious task. Thus, automatic image segmentation became essential for diagnosis assistance. Segmentation consists in dividing the image into homogeneous and significant regions. We focus on hidden Markov random fields referred to as HMRF to model the problem of segmentation. This modelisation leads to a classical function minimisation problem. Broyden-Fletcher-Goldfarb-Shanno algorithm referred to as BFGS is one of the most powerful methods to solve unconstrained optimisation problem. …
32×32 winner-take-all matrix with single winner selection
2010
A 32 × 32 winner-take-all (WTA) matrix with single winner selection is introduced. A high-resolution gain-boosted regulated-cascode WTA circuit is used in a first competition stage. Because of the large number of competing cells the possibility of a multiple winners situation arises. A single winner is obtained by means of a digital inhibitory circuit following each WTA analogue amplifier. Simulations show that this mixed analogue-digital circuit achieves its objective with a current resolution of approximately 10 nA (0.8% of the maximum input current in the simulated case). A time response of ?s can be achieved.
Path-wise versus kinetic modeling for equilibrating non-Langevin jump-type processes
2014
We discuss two independent methods of solution of a master equation whose biased jump transition rates account for long jumps of L\'{e}vy-stable type and nonetheless admit a Boltzmannian (thermal) equilibrium to arise in the large time asymptotics of a probability density function $\rho (x,t)$. Our main goal is to demonstrate a compatibility of a {\it direct} solution method (an explicit, albeit numerically assisted, integration of the master equation) with an {\it indirect} path-wise procedure, recently proposed in [Physica {\bf A 392}, 3485, (2013)] as a valid tool for a dynamical analysis of non-Langevin jump-type processes. The path-wise method heavily relies on an accumulation of large…
An Heuristic Approach for the Training Dataset Selection in Fingerprint Classification Tasks
2015
Fingerprint classification is a key issue in automatic fingerprint identification systems. It aims to reduce the item search time within the fingerprint database without affecting the accuracy rate. In this paper an heuristic approach using only the directional image information for the training dataset selection in fingerprint classification tasks is described. The method combines a Fuzzy C-Means clustering method and a Naive Bayes Classifier and it is composed of three modules: the first module builds the working datasets, the second module extracts the training images dataset and, finally, the third module classifies fingerprint images in four classes. Unlike literature approaches using …
Universal Design of Information Sharing Tools for Disaster Risk Reduction
2019
International audience; Disaster information sharing tools are an important aspect of disaster resilience, and it is of utmost importance that these tools are accessible and usable for as many potential users as possible. In this paper, we evaluate the accessibility of a selection of tools for crowdsourcing disaster situation information. As our evaluation shows that the selected tools are not fully accessible, we provide recommendations for mitigation, as well as highlight the importance of further research in this area.
On Strong Convergence of Halpern’s Method for Quasi-Nonexpansive Mappings in Hilbert Spaces
2016
In this paper, we introduce a Halpern’s type method to approximate common fixed points of a nonexpansive mapping T and a strongly quasi-nonexpansive mappings S, defined in a Hilbert space, such that I − S is demiclosed at 0. The result shows as the same algorithm converges to different points, depending on the assumptions of the coefficients. Moreover, a numerical example of our iterative scheme is given.
Adjacent vertices can be hard to find by quantum walks
2018
Quantum walks have been useful for designing quantum algorithms that outperform their classical versions for a variety of search problems. Most of the papers, however, consider a search space containing a single marked element. We show that if the search space contains more than one marked element, their placement may drastically affect the performance of the search. More specifically, we study search by quantum walks on general graphs and show a wide class of configurations of marked vertices, for which search by quantum walk needs Ω(N) steps, that is, it has no speed-up over the classical exhaustive search. The demonstrated configurations occur for certain placements of two or more adjace…