Search results for "A* algorithm"
showing 10 items of 2538 documents
The metaphorical species: Evolution, adaptation and speciation of metaphors
2015
Studying cartoons about the economic crisis and focusing on a pair of scissors as a symbol, I prove how they first turn into unambiguous metaphor for the economic crisis and then experience an evolution in order to adapt to new communication contexts. Along these processes, they undergo more complex changes such as coadaptation and speciation. This has allowed for the scissors meme as a symbol of economic cutbacks to permeate society, and for its metaphorical use to occupy many disparate communication scenarios, unlike other symbolic elements that were also used, but turned out to be less cognitively efficient and therefore offered fewer evolutionary possibilities.
Effect of inter-crystal scatter on estimation methods for random coincidences and subsequent correction.
2008
Random coincidences can contribute substantially to the background in positron emission tomography (PET). Several estimation methods are being used for correcting them. The goal of this study was to investigate the validity of techniques for random coincidence estimation, with various low-energy thresholds (LETs). Simulated singles list-mode data of the MADPET-II small animal PET scanner were used as input. The simulations have been performed using the GATE simulation toolkit. Several sources with different geometries have been employed. We evaluated the number of random events using three methods: delayed window (DW), singles rate (SR) and time histogram fitting (TH). Since the GATE simula…
Modelling complex dynamics and distributed generation of knowledge with bacterial-based algorithms
2014
Este estudio tuvo como objetivo demostrar que las sociedades conectadas y heterogéneas con intercambios entre pares (P2P) son más resilientes que las centralizadas y homogéneas. En el modelado basado en agentes, se modelizan agentes con racionalidad limitada que interactúan en un entorno común guiado por reglas locales, lo que lleva a Sistemas Adaptativos Complejos (CAS) que se denominan 'sociedades artificiales'. Estos modelos simplificados de sociedades humanas crecen de abajo hacia arriba en entornos computacionales y pueden utilizarse como un laboratorio para probar algunas hipótesis. Hemos demostrado que en un modelo basado en interacciones libres entre agentes autónomos, los resultado…
Individual Variability and Average Reliability in Parallel Networks of Heterogeneous Biological and Artificial Nanostructures
2013
We simulate the collective electrical response of heterogeneous ensembles of biological and artificial nanostructures whose individual threshold potentials show a significant variability. This problem is of current interest because nanotechnology is bound to produce nanostructures with a significant experimental variability in their individual physical properties. This diversity is also present in biological systems that are however able to process information efficiently. The nanostructures considered are the ion channels of biological membranes, nanowire field-effect transistors, and metallic nanoparticle-based single electron transistors. These systems are simulated with canonical models…
Geometry/Time Measurement/Sundials Graphical Resolution via Algorithmic and Parametric Processes
2018
Every people, in every historical period, developed methods to measure Time both at a daily scale and at a yearly scale. Some of them constructed sundials to represent the apparent trajectory of the Sun around the Earth, by using and developing tools from descriptive and projective Geometry, mainly. This subject acquired a great multidisciplinary interest since ancient times, also for Science of Representation applications. This study presents the first results of an ongoing research concerning some aspects related to Time Measurement. The geometric-spatial setting of the Sun-Earth system is described and is structured parametrically via algorithms, following the known conventions shared an…
Quantum Walks on Two-Dimensional Grids with Multiple Marked Locations
2016
The running time of a quantum walk search algorithm depends on both the structure of the search space graph and the configuration of marked locations. While the first dependence has been studied in a number of papers, the second dependence remains mostly unstudied. We study search by quantum walks on the two-dimensional grid using the algorithm of Ambainis, Kempe and Rivosh [AKR05]. The original paper analyses one and two marked locations only. We move beyond two marked locations and study the behaviour of the algorithm for an arbitrary configuration of marked locations. In this paper, we prove two results showing the importance of how the marked locations are arranged. First, we present tw…
A Greedy Algorithm for Hierarchical Complete Linkage Clustering
2014
We are interested in the greedy method to compute an hierarchical complete linkage clustering. There are two known methods for this problem, one having a running time of \({\mathcal O}(n^3)\) with a space requirement of \({\mathcal O}(n)\) and one having a running time of \({\mathcal O}(n^2 \log n)\) with a space requirement of Θ(n 2), where n is the number of points to be clustered. Both methods are not capable to handle large point sets. In this paper, we give an algorithm with a space requirement of \({\mathcal O}(n)\) which is able to cluster one million points in a day on current commodity hardware.
A simple algorithm to evaluate the local symmetry at each point of a closed contour
1995
In this work, contour symmetry is evaluated as a numeric feature for each point of the shape outline, using only the positions of a local vicinity of points. A measure is defined, named Local Symmetric Deficiency (LSD), so that the lower this quantity is, the higher the symmetry will be in the local region considered. This approach is simpler than related previous ones both from a conceptual point of view and for its implementation, since it is reduced just to a suitable manipulation of the Freeman chain code of the curve studied. Its computational cost is very low and it has the advantages of a parallel algorithm, since values for LSD can be computed for each point independently.
"Indexing structures for approximate string matching
2003
In this paper we give the first, to our knowledge, structures and corresponding algorithms for approximate indexing, by considering the Hamming distance, having the following properties. i) Their size is linear times a polylog of the size of the text on average. ii) For each pattern x, the time spent by our algorithms for finding the list occ(x) of all occurrences of a pattern x in the text, up to a certain distance, is proportional on average to |x| + |occ(x)|, under an additional but realistic hypothesis.
A reconstruction algorithm for L-convex polyominoes
2006
AbstractWe give an algorithm that uniquely reconstruct an L-convex polyomino from the size of some special paths, called bordered L-paths.