810 resultados para Linde-Buzo-Gray Algorithm


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Application of optimization algorithm to PDE modeling groundwater remediation can greatly reduce remediation cost. However, groundwater remediation analysis requires a computational expensive simulation, therefore, effective parallel optimization could potentially greatly reduce computational expense. The optimization algorithm used in this research is Parallel Stochastic radial basis function. This is designed for global optimization of computationally expensive functions with multiple local optima and it does not require derivatives. In each iteration of the algorithm, an RBF is updated based on all the evaluated points in order to approximate expensive function. Then the new RBF surface is used to generate the next set of points, which will be distributed to multiple processors for evaluation. The criteria of selection of next function evaluation points are estimated function value and distance from all the points known. Algorithms created for serial computing are not necessarily efficient in parallel so Parallel Stochastic RBF is different algorithm from its serial ancestor. The application for two Groundwater Superfund Remediation sites, Umatilla Chemical Depot, and Former Blaine Naval Ammunition Depot. In the study, the formulation adopted treats pumping rates as decision variables in order to remove plume of contaminated groundwater. Groundwater flow and contamination transport is simulated with MODFLOW-MT3DMS. For both problems, computation takes a large amount of CPU time, especially for Blaine problem, which requires nearly fifty minutes for a simulation for a single set of decision variables. Thus, efficient algorithm and powerful computing resource are essential in both cases. The results are discussed in terms of parallel computing metrics i.e. speedup and efficiency. We find that with use of up to 24 parallel processors, the results of the parallel Stochastic RBF algorithm are excellent with speed up efficiencies close to or exceeding 100%.

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This paper describes the formulation of a Multi-objective Pipe Smoothing Genetic Algorithm (MOPSGA) and its application to the least cost water distribution network design problem. Evolutionary Algorithms have been widely utilised for the optimisation of both theoretical and real-world non-linear optimisation problems, including water system design and maintenance problems. In this work we present a pipe smoothing based approach to the creation and mutation of chromosomes which utilises engineering expertise with the view to increasing the performance of the algorithm whilst promoting engineering feasibility within the population of solutions. MOPSGA is based upon the standard Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and incorporates a modified population initialiser and mutation operator which directly targets elements of a network with the aim to increase network smoothness (in terms of progression from one diameter to the next) using network element awareness and an elementary heuristic. The pipe smoothing heuristic used in this algorithm is based upon a fundamental principle employed by water system engineers when designing water distribution pipe networks where the diameter of any pipe is never greater than the sum of the diameters of the pipes directly upstream resulting in the transition from large to small diameters from source to the extremities of the network. MOPSGA is assessed on a number of water distribution network benchmarks from the literature including some real-world based, large scale systems. The performance of MOPSGA is directly compared to that of NSGA-II with regard to solution quality, engineering feasibility (network smoothness) and computational efficiency. MOPSGA is shown to promote both engineering and hydraulic feasibility whilst attaining good infrastructure costs compared to NSGA-II.

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Audio coding is used to compress digital audio signals, thereby reducing the amount of bits needed to transmit or to store an audio signal. This is useful when network bandwidth or storage capacity is very limited. Audio compression algorithms are based on an encoding and decoding process. In the encoding step, the uncompressed audio signal is transformed into a coded representation, thereby compressing the audio signal. Thereafter, the coded audio signal eventually needs to be restored (e.g. for playing back) through decoding of the coded audio signal. The decoder receives the bitstream and reconverts it into an uncompressed signal. ISO-MPEG is a standard for high-quality, low bit-rate video and audio coding. The audio part of the standard is composed by algorithms for high-quality low-bit-rate audio coding, i.e. algorithms that reduce the original bit-rate, while guaranteeing high quality of the audio signal. The audio coding algorithms consists of MPEG-1 (with three different layers), MPEG-2, MPEG-2 AAC, and MPEG-4. This work presents a study of the MPEG-4 AAC audio coding algorithm. Besides, it presents the implementation of the AAC algorithm on different platforms, and comparisons among implementations. The implementations are in C language, in Assembly of Intel Pentium, in C-language using DSP processor, and in HDL. Since each implementation has its own application niche, each one is valid as a final solution. Moreover, another purpose of this work is the comparison among these implementations, considering estimated costs, execution time, and advantages and disadvantages of each one.

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Os mares e oceanos vêm sendo intensamente impactados por diversas atividades antrópicas, as quais vêm provocando a diminuição dos recursos naturais devido a sobrepesca, poluição e o aumento do tráfego de embarcações. A perda de hábitat crítico, decorrente do intenso uso das zonas litorâneas, tem sido uma das maiores ameaças aos cetáceos costeiros. O Chile possui uma grande diversidade de baleias e golfinhos, porém o golfinho-chileno (Cephalorhynchus eutropia) é a única espécie endêmica às águas costeiras deste país. Na porção sul da distribuição de C. eutropia (fiordes e canais) há uma grande sobreposição da indústria de aqüicultura (uma das atividades antrópicas mais importantes no sul do Chile) aos principais locais de ocorrência desta espécie. Observações a partir de terra foram realizadas com o objetivo de estudar a seleção de hábitat dos golfinhos-chilenos em pequena escala espacial e avaliar as reações comportamentais desta espécie em relação ao tráfego de embarcações presente na Baía Yaldad, local onde há intenso cultivo de mexilhão e de salmão. Utilizou-se um teodolito para marcar a posição dos golfinhos e um total de 293,5 horas de esforço foram realizadas entre os meses de janeiro a abril de 2002. O padrão de uso de hábitat, concentrado a uma pequena porção da área de estudo, mostrou que os golfinhos selecionam locais rasos, próximos à costa e próximo aos rios. As atividades dos golfinhos foram influenciadas pelo regime de maré e o forrageio foi a principal atividade realizada na baía. . A aqüicultura representou um impacto negativo, devido à redução de espaço disponível aos animais e ao aumento do tráfego de embarcação, que afetou consideravelmente os padrões comportamentais de C. eutropia. A presença, os padrões de movimento e uso de hábitat dos golfinhos-chilenos devem ser levados em consideração na regulamnetação das atividades de aqüicultura e nas políticas de manejo dos ecossistemas costeiros. Visto que predadores topo de cadeia podem ser considerados indicadores ambientais, a conservação dos ecossistemas marinhos poderia ser abordada pela descrição dos movimentos e seleção de hábitat de cetáceos que atuariam como “espécies guarda-chuva”.

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Alasdair Gray is now an established figure in the Scottish literary scene and has numerous claims to be considered an important voice writing in English. First Lanark: A Life in Four Books (1981) and then 1982 Janine (1984) contributed to the recognition of Gray as one of the founding fathers of the new Scottish writing and as a figure of importance in international contemporary fiction due to his innovative, experimental and postmodernist novels. As the title of this dissertation - “Alasdair Gray’s 1982 Janine (1984): A Postmodernist Scottish Novel” - suggests, it aims at analysing the author’s second novel, 1982 Janine (1984), in a thematic and formal perspective, in order to justify the choice of the terms - Postmodernist and Scottish - to classify this novel. 1982 Janine projects a world through Jock McLeish’s mind and is a powerful stream-of-consciousness narrative. Jock is an alcoholic who lives a personal crisis and, therefore, tries to escape from his depressing reality through sexual fantasies and political diatribes. During a single night in a Scottish hotel room, he drinks and dreams, and spends the whole night alone with his fantasies and fears, his memories and hopes. In Chapter 11, the most daring experimental section of the novel, Jock attempts to commit suicide by taking an overdose of tablets with alcohol but fails. Following this, he decides to review his life and make for a new beginning; the novel thus closing with an optimistic note. Also, the narrative is based on a constant interweaving of sex fantasy with political satire, that is, it is through his protagonist that Gray manages to convey the state of Scotland as well as the concerns and aspirations of the Scottish people and then, proceed to a political and social critique. This dissertation appears structured in three chapters. In Chapter I - “Alasdair Gray: A Postmodernist Scottish Writer” - I present Gray as a powerful postmodernist writer who also sees himself as a Scottish author, and more particularly as a Glaswegian, who concentrates on Scottish subject matter in his literary work. In a first section, I offer a brief survey of the Scottish literary scene from the fourteenth to the twentieth century, in order to understand Gray’s choice of setting and themes and to check his influence or indebtedness to previous Scottish authors. As 1982 Janine is also a good example of selfconscious experimental writing, in a second section, I present various seminal fictional works that introduced and developed experimentalism in British fiction, in order to evaluate the influence of modernist developments in form and technique on recent experimental writing. The third section consists of an introduction to Gray’s work for he is not only a novelist, but also an artist, a playwright, a poet, an activist and a scholar. Chapter II - “Postmodernist Features in 1982 Janine” - aims at listing and examining the postmodernist devices that the novel includes, in what content and form are concerned. On the one hand, the use of a developed type of the modernist stream of consciousness, the presence of a protagonist who feels entrapped in a specific system, the quest for freedom, the incoherence and fragmentation of time, the nonchronological order of the narrative, the blending of fantasy and “reality”, as well as the importance of the Scottish material are definitely current aspects within postmodernist literature that can be found in Gray’s novel. On the other hand, the handling of literary self-conscious devices, such as typographical experimentation, presence of metafiction and intertextuality, and inclusion of an Epilogue, are likewise among recurrent postmodernist features. As the title - “A Narratological Analysis of 1982 Janine” - evidences, Chapter III offers a description of the mechanics of the narrative and its functioning in order to better understand the narrative technique of postmodernist fiction. This study is based primarily on Gérard Genette’s theoretical framework and terminology, presented in Narrative Discourse: An Essay in Method, an analytical tool that allows me to provide a more objective and scientific analysis. Hence, I follow the Genettian division of narrative discourse in Time, Mood and Voice while examining the novel. Finally, I proceed to a description of the intertextual relationships 1982 Janine establishes with other texts.

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LEÃO, Adriano de Castro; DÓRIA NETO, Adrião Duarte; SOUSA, Maria Bernardete Cordeiro de. New developmental stages for common marmosets (Callithrix jacchus) using mass and age variables obtained by K-means algorithm and self-organizing maps (SOM). Computers in Biology and Medicine, v. 39, p. 853-859, 2009

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The evolution of wireless communication systems leads to Dynamic Spectrum Allocation for Cognitive Radio, which requires reliable spectrum sensing techniques. Among the spectrum sensing methods proposed in the literature, those that exploit cyclostationary characteristics of radio signals are particularly suitable for communication environments with low signal-to-noise ratios, or with non-stationary noise. However, such methods have high computational complexity that directly raises the power consumption of devices which often have very stringent low-power requirements. We propose a strategy for cyclostationary spectrum sensing with reduced energy consumption. This strategy is based on the principle that p processors working at slower frequencies consume less power than a single processor for the same execution time. We devise a strict relation between the energy savings and common parallel system metrics. The results of simulations show that our strategy promises very significant savings in actual devices.

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This research aims to study wall paitings created by artists Newton Navarro and Dorian Gray, installed in public buildings of modern architecture, in Natal/RN from 1950 to 1970. The subject is seen by focusing on its concepts and characterization, linked to the ideia of integration of the arts and the meaning of modern mural painting in Brasil. The study presents an analyses of those paitings considering themes, techiniques and dimensions, comparing the solutions of local artists with brasilian muralist painters, particularly the work of Cândido Portinari. Registers of artistic works show a view of the inclusion of arts in modern architecture in the city

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This paper presents a method for automatic identification of dust devils tracks in MOC NA and HiRISE images of Mars. The method is based on Mathematical Morphology and is able to successfully process those images despite their difference in spatial resolution or size of the scene. A dataset of 200 images from the surface of Mars representative of the diversity of those track features was considered for developing, testing and evaluating our method, confronting the outputs with reference images made manually. Analysis showed a mean accuracy of about 92%. We also give some examples on how to use the results to get information about dust devils, namelly mean width, main direction of movement and coverage per scene. (c) 2012 Elsevier Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Glutamate NMDA receptor activation within the periaqueductal gray (PAG) leads to antinociceptive, autonomic and behavioral responses characterized as the fear reaction. Considering that NMDA receptor triggers activation of neuronal nitric oxide synthase (nNOS), enzyme that produces nitric oxide (NO), this study investigated the effects of intra-PAG infusions of NPLA (N omega-propyl-L-arginine), an nNOS inhibitor, on behavioral and antinociceptive responses induced by local injection of NMDA receptor agonist in mice. The behaviors measured were frequency of jumping and rearing as well as duration (in seconds) of running and freezing. Nociception was assessed during the second phase of the formalin test (injection of 50 mu l of formalin 2.5% into the dorsal surface of the right hind paw). Five to seven days after stereotaxic surgery for intracerebral cannula implantation, mice were injected with formalin into the paw, and 10 min later, they received intra-dPAG injection of NPLA (0, 0.2, or 0.4 nmol/0.1 mu l). Ten minutes later, they were injected with NMDA (N-methyl-D-aspartate: 0 or 0.04 nmol/0.1 mu l) into the same midbrain site and were immediately placed in glass holding cage for recording the defensive behavior and the time spent on licking the injected paw with formalin during a period of 10 min. Microinjections of NMDA significantly decreased nociception response and produced jumping, running, and freezing reactions. Intra-dPAG injections of NPLA (0.4 nmol) completely blocked the NMDA effects without affecting either behavioral or nociceptive responses in intra-dPAG saline-injected animals, except for the rearing frequency that was increased by the nNOS inhibitor. These results strongly suggest the involvement of NO within the PAG in the antinociceptive and defensive reactions induced by local glutamate NMDA receptor activation in this midbrain structure. (c) 2006 Elsevier B.V. All rights reserved.