The National University of Austral Patagonia is an Argentine national university in Santa Cruz Province. The university is divided into four campuses, located in the cities of Caleta Olivia , Río Gallegos , San Julián and Río Turbio , and was founded in 1995, by national law 24.446. Wikipedia.
Villagra A.,National University of Patagonia Austral |
Alba E.,University of Malaga |
Leguizamon G.,National University of San Luis
Computational Intelligence and Neuroscience | Year: 2016
This work presents the results of a new methodology for hybridizing metaheuristics. By first locating the active components (parts) of one algorithm and then inserting them into second one, we can build efficient and accurate optimization, search, and learning algorithms. This gives a concrete way of constructing new techniques that contrasts the spread ad hoc way of hybridizing. In this paper, the enhanced algorithm is a Cellular Genetic Algorithm (cGA) which has been successfully used in the past to find solutions to such hard optimization problems. In order to extend and corroborate the use of active components as an emerging hybridization methodology, we propose here the use of active components taken from Scatter Search (SS) to improve cGA. The results obtained over a varied set of benchmarks are highly satisfactory in efficacy and efficiency when compared with a standard cGA. Moreover, the proposed hybrid approach (i.e., cGA+SS) has shown encouraging results with regard to earlier applications of our methodology. © 2016 Andrea Villagra et al.
Alba E.,University of Malaga |
Villagra A.,National University of Patagonia Austral
Studies in Computational Intelligence | Year: 2013
Cellular Genetic Algorithm (cGA) and Particle Swam Optimization (PSO) are two powerful metaheuristics being used successfully since their creation for the resolution of optimization problems. In this work we present two hybrid algorithms based on a cGA with the insertion of components from PSO. We aim to achieve significant numerical improvements in the results obtained by a cGA in combinatorial optimization problems. We here analyze the performance of our hybrids using a set of different problems. The results obtained are quite satisfactory in efficacy and efficiency. © 2013 Springer-Verlag Berlin Heidelberg.
Vidal P.,National University of Patagonia Austral |
Alba E.,University of Malaga
Studies in Computational Intelligence | Year: 2010
The availability of low cost powerful parallel graphic cards has estimulated a trend to implement diverse algorithms on Graphic Processing Units (GPUs). In this paper we describe the design of a parallel Cellular Genetic Algorithm (cGA) on a GPU and then evaluate its performance. Beyond the existing works on masterslave for fitness evaluation, we here implement a cGA exploiting data and instructions parallelism at the population level. Using the CUDA language on a GTX-285 GPU hardware, we show how a cGA can profit from it to create an algorithm of improved physical efficiency and numerical efficacy with respect to a CPU implementation. Our approach stores individuals and their fitness values in the globalmemory of the GPU. Both, fitness evaluation and genetic operators are implemented entirely on GPU (i.e. no CPU is used). The presented approach allows us benefit from the numerical advantages of cGAs and the efficiency of a low-cost but powerful platform. © 2010 Springer-Verlag Berlin Heidelberg.
Trejo N.,National University of Patagonia Austral |
Casas S.,National University of Patagonia Austral |
Hallar K.,National University of Patagonia Austral
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012
Grid computing and Feature-oriented Development Software are emerging technologies, which can be combined to analyze, model, and specify Grid services. In a Grid environment, there are a large number of similar resources provided by different parties, that may provide the same functionality, but different Quality of Service (QoS) measures. A feature-based approach is presented to optimize the development of Grid services and Grid service composition. WSDL specification is extended to contain useful description of both functional and non-functional characteristics by mean Design by Contract technique. In this way, Grid users can specify their QoS expectations and select suitable resources and use them for their Grid workflow at design time before its execution on the Grid. © 2012 Springer-Verlag.
Lizarralde Z.I.,National University of Patagonia Austral |
Pittaluga S.,National University of Patagonia Austral
Thalassas | Year: 2011
The aim of this work was to analyze spatial and temporal variations in composition and abundance of benthic species assemblages in an intertidal environment of the Río Gallegos Estuary, Patagonia, Argentina (51° 35' S 69° W). Species distribution and its temporal fluctuations were analyzed using multivariate statistical methods. Different species assemblages were observed, their distribution being related to the tidal level and type of intertidal sediment. The polychaete Scolecolepides uncinatus was dominant in a species assemblage restricted to the high intertidal levels, which are characterized by silty clay sediments. At the intermediate intertidal level, the number of species and total macrofauna abundance increased; at this level, the clam Darina solenoides and the mussel Mytilus edulis platensis were dominant. At the low levels, which are composed of fine sediments, the polychaete Clymenella minor and the bivalve Mysella sp. were dominant. Temporal variations detected in species abundance were mainly due to the incorporation of recruits in the population, especially of the most abundant species.
Montani H.,National University of Patagonia Austral |
Schaposnik F.A.,National University of La Plata
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
We construct fermionic Lagrangians with anisotropic scaling z=2, the natural counterpart of the usual z=2 Lifshitz field theories for scalar fields. We analyze the issue of chiral symmetry, construct the Noether axial currents and discuss the chiral anomaly giving explicit results for two-dimensional case. We also exploit the connection between detailed balance and the dynamics of Lifshitz theories to find different z=2 fermionic Lagrangians and construct their supersymmetric extensions. © 2012 American Physical Society.
Brunini A.,National University of Patagonia Austral |
Zanardi M.,National University of La Plata |
Monthly Notices of the Royal Astronomical Society | Year: 2016
We present numerical simulations of the evolution of synthetic transneptunian binaries (TNBs) under the influence of the solar perturbation, tidal friction, and collisions with the population of classical Kuiper belt objects (KBOs).We show that these effects, acting together, have strongly sculpted the primordial population of TNBs. If the population of classical KBOs have a powerlawsize distribution as the ones that are inferred from recent observational surveys, the fraction of surviving binaries at present would be ~70 per cent of the primordial population. The orbits of the surviving synthetic systems match reasonably well the observed sample. The collisional process excites the mutual orbital eccentricity of the binaries, acting against the effect of tides. Therefore only ~10 per cent of the objects reach total orbital circularization (e ≤ 10-4). In addition, our results predict that the population of contact binaries in the transneptunian region should be small. Ultrawide binaries are naturally obtained by the combined action of Kozai cycles and tidal friction and collisional evolution, being the number and orbital distribution of them very similar to the ones of the observed population. © 2015 The Authors.
Cruz I.,National University of Patagonia Austral
Archaeofauna | Year: 2015
The results of actualistic taphonomic studies in Patagonia aimed at evaluating the preservation potential of vertebrates with different body sizes are presented. Large vertebrates include the guanaco (Lama guanicoe); the South American sea lion (Otaria flavescens), and a flightless bird belonging to the Ratites, the Lesser Rhea (Rhea pennata). Small vertebrates are flying birds and a member of the Spheniscidae Family, the Magellanic penguin (Spheniscus magellanicus). The large vertebrate bone record is the result of a long period of exposure on the ground surface, and its destruction is mainly due to weathering. The flying birds and penguin bone records are instead conditioned by a shorter subaerial exposure time. The future fossil records of these two groups vertebrates will be thus completely different as regards their integrity (sensu Binford, 1981) and their tendency towards spatial and temporal mixing.
Escalada J.P.,National University of Patagonia Austral |
Arce V.B.,CONICET |
Porcal G.V.,National University of Rio Cuarto |
Biasutti M.A.,National University of Rio Cuarto |
And 3 more authors.
Water Research | Year: 2014
The production of dichlorophen (2,2'-methylenebis(4-chlorophenol), DCP) and its use as an anthelmintic and in pesticide products result in its direct release to the environment. To the purpose of modelling the possible photodegradation routes of DCP sorbed on sediments or suspended particles, the synthesis and characterization of silica nanoparticles modified with DCP (NP-DCP) is reported.The reactivity of NP-DCP with the excited states of riboflavin, a sensitizer usually present in natural waters, and with singlet oxygen were investigated. Comparison of the kinetic results obtained here to those previously reported for irradiated aqueous solutions of DCP allowed the discussion of the effect of adsorption of the pesticide on its photodegradation.We show with the aid of computer simulations that in natural waters the relevance of the different photodegradation routes dichlorophen is very much affected by attachment to sediments. © 2013 Elsevier Ltd.
Borella F.,CONICET |
Cruz I.,National University of Patagonia Austral
Quaternary International | Year: 2012
Archaeological deposits in continental Patagonia that allow an adequate discussion of the exploitation of seabirds, particularly the Spheniscidae, are scarce. In many cases, characteristics of bone assemblages seem to indicate the natural incorporation of penguin bones into archaeological contexts. This suggests it is not always possible to support the argument that the presence of penguin remains indicates, a priori, consumption by humans. The Bajada de los Pescadores (BP2) site, San Matías Gulf (Río Negro, Patagonia, Argentina), provides a case study that allows the origin of these deposits and their contents to be evaluated in terms of the exploitation of penguins and other marine resources by hunter-gatherers during the Late Holocene. This paper discusses the origin of the archaeological deposit, its context, and the agents involved in its formation. The analysis used criteria formulated previously in the framework of actualistic taphonomic observations, with the aim of assessing the integrity of this sample, and evaluating its contribution towards clarifying the role of penguins in the subsistence of people on the northern Patagonian coast. © 2012 Elsevier Ltd and INQUA.