2,358 research outputs found
A software architecture for consensus based replication
Orientador: Luiz Eduardo BuzatoTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Esta tese explora uma das ferramentas fundamentais para construção de sistemas distribuídos: a replicação de componentes de software. Especificamente, procuramos resolver o problema de como simplificar a construção de aplicações replicadas que combinem alto grau de disponibilidade e desempenho. Como ferramenta principal para alcançar o objetivo deste trabalho de pesquisa desenvolvemos Treplica, uma biblioteca de replicação voltada para construção de aplicações distribuídas, porém com semântica de aplicações centralizadas. Treplica apresenta ao programador uma interface simples baseada em uma especificação orientada a objetos de replicação ativa. A conclusão que defendemos nesta tese é que é possível desenvolver um suporte modular e de uso simples para replicação que exibe alto desempenho, baixa latência e que permite recuperação eficiente em caso de falhas. Acreditamos que a arquitetura de software proposta tem aplicabilidade em qualquer sistema distribuído, mas é de especial interesse para sistemas que não são distribuídos pela ausência de uma forma simples, eficiente e confiável de replicá-losAbstract: This thesis explores one of the fundamental tools for the construction of distributed systems: the replication of software components. Specifically, we attempted to solve the problem of simplifying the construction of high-performance and high-availability replicated applications. We have developed Treplica, a replication library, as the main tool to reach this research objective. Treplica allows the construction of distributed applications that behave as centralized applications, presenting the programmer a simple interface based on an object-oriented specification for active replication. The conclusion we reach in this thesis is that it is possible to create a modular and simple to use support for replication, providing high performance, low latency and fast recovery in the presence of failures. We believe our proposed software architecture is applicable to any distributed system, but it is particularly interesting to systems that remain centralized due to the lack of a simple, efficient and reliable replication mechanismDoutoradoSistemas de ComputaçãoDoutor em Ciência da Computaçã
A Philosophically Appealing Nietzschean Theory of Value
This thesis is an attempt to bring forth a novel and philosophically appealing reading of Nietzsche, especially as it pertains to his theory of value. I define philosophically appealing as the view with the least amount of inconsistencies that still reaches a simple and logical conclusion. I explore questions regarding Nietzsche’s nihilism, his normative and metaphysical claims, as well as his view on human nature. I aim to satisfy sophisticated readers by investigating complex philosophical issues related to my interpretation of Nietzsche. I also aim to satisfy less sophisticated readers by explaining how my view is applicable, and beneficial, to one’s life. Given that there’s no widespread agreement as to what reading of Nietzsche is correct, the goal of my thesis is to contribute meaningfully to this ongoing debate
Green stabilized sulfate-rich dispersive soil through residues and industrial by-products
Solos dispersivos e sulfatados emergem como uma grande preocupação ao desenvolvimento da infraestrutura. Dado suas características, tipos de solos como estes possuem uma alta suscetibili-dade ao desenvolvimento de processos erosivos, além da possibilidade do desenvolvimento de mine-rais expansivos quando tratados à base de cálcio. Neste sentido, surge a demanda por alternativas a estabilizantes como o cimento Portland e a cal calcítica. Com isto, o presente trabalho propõe um novo estabilizante à base de vidro moído (um subproduto da produção de fibras de vidro) e cal de carbureto (um resíduo proveniente da produção de gás acetileno). Sua eficiência foi averiguada através da resis-tência à compressão dos compósitos propostos. Para isto, corpos-de-prova foram moldados com dis-tintas dosagens tendo-se como fatores controláveis o teor de vidro moído, o teor de cal de carbureto, o teor de umidade de moldagem e o peso específico aparente seco das amostras. Ambos, subproduto e resíduo, se mostraram eficazes ao tratamento de solos dispersivos e sulfatados, levando a resistências à compressão da ordem de 4 MPa. Da análise estatística, nesta ordem de importância, os fatores peso específico aparente seco, teor de vidro moído e teor de cal de carbureto, se mostram significantes para um nível de significância de 5%. Enquanto que o teor de umidade de moldagem se mostrou não-signi-ficativo. Por fim, por meio de uma regressão não-linear, é proposta uma otimização de valores para que se possa atingir a máxima resistência desejada.Sulfate-rich dispersive soils became an enormous concern to infrastructure development. Owing to its characteristics, these type of soils are highly susceptible to erosions process, as well as, to expansive minerals growth when calcium based stabilizers are applied. Therefore, alternative binders must be found alternatively to ordinary Portland cement and lime. In this context, the present study aims to develop an alternative soil stabilizer, composed by ground glass (a byproduct from fiberglass produc-tion) and carbide lime (an industrial residue from acetylene gas production). To access the efficiency of the proposed stabilization, unconfined compressive strength was performed. Therefore, soil-ground glass-carbide lime blends were molded at distinct dosages, with ground glass, carbide lime, molding moisture content and dry unit weight being varied throughout the tests. Results has shown that both, residue and byproduct arise as an innovative approach to sulfate-rich dispersive soil treatment, where unconfined compressive strengths up to 4 MPa were reached. Additionally, regarding tostatistical anal-ysis, following this sequence, dry unit weight, ground glass amount and carbide lime content were sta-tistical significant to a significance level of 5%. Whereas, molding moisture content was not a significant parameter. Finally, based on anon-linear regression, an experimental optimization was proposed aim-ing to obtain the maximum unconfined compressive strength requeste
Self-motivated agents that learn
Tese de mestrado em Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013We propose an architecture for the creation of agents with the capacity to learn how to act autonomously, from their interactions with the environment. Predefined solutions such as manually specified behaviors, goals or rewards are avoided in order to maximize autonomous adaptation to unforeseen conditions. We use internal needs to motivate agents to act in an attempt to fulfil them. As a consequence of its interactions with the environment, agents make observations which are used to formulate hypotheses and discover the rules that govern the relationship between the agents actions and their consequences. These rules are then used as criteria in the decision making process. Thus, agents behaviors depend on previous interactions and evolve with experience. We started by proposing a single agent architecture and created simple agents defined by sensors, needs and actuators. These agents adapted autonomously to the environment by discovering behaviors which fulfilled their needs. The single agent approach did not scale well neither allowed the satisfaction of multiple needs simultaneously. In order to face these shortcomings we propose a multiagent architecture which solves the scalability problem found in the single agent approach and offers the capacity to fulfil several needs simultaneously
DETERMINATION OF GEO-INFORMATION CHARACTERISTICS IN THE USER INTERACTION WITH A SYSTEM FOR BETTERMENT TAX CALCULATION
In this paper, we present some results of research work that seeks to determine how the characteristics of geoinformation should be considered and included in the design of users' interfaces for a geoinformation system. Through well-known techniques of requirements engineering, we collected and documented the information obtained from potential users of a geoinformation system designed to be used for calculation of betterment taxes. Furthermore, we analyzed the users’ requirements to determine the characteristics of geoinformation in this particular case of tax calculation. We try to define how those geoinformation characteristics can be included in the requirements specification and how to consider them to help designing better geoinformation systems interfaces
On the distribution of an effective channel estimator for multi-cell massive MIMO
Accurate channel estimation is of utmost importance for massive MIMO systems to provide significant improvements in spectral and energy efficiency. In this work, we present a study on the distribution of a simple but yet effective and practical channel estimator for multi-cell massive MIMO systems suffering from pilot-contamination. The proposed channel estimator performs well under moderate to aggressive pilot contamination scenarios without previous knowledge of the inter-cell large-scale channel coefficients and noise power, asymptotically approximating the performance of the linear MMSE estimator as the number of antennas increases. We prove that the distribution of the proposed channel estimator can be accurately approximated by the circularly-symmetric complex normal distribution, when the number of antennas, M, deployed at the base station is greater than 10
Sorting signed permutations by short operations
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Background: During evolution, global mutations may alter the order and the orientation of the genes in a genome. Such mutations are referred to as rearrangement events, or simply operations. In unichromosomal genomes, the most common operations are reversals, which are responsible for reversing the order and orientation of a sequence of genes, and transpositions, which are responsible for switching the location of two contiguous portions of a genome. The problem of computing the minimum sequence of operations that transforms one genome into another - which is equivalent to the problem of sorting a permutation into the identity permutation - is a well-studied problem that finds application in comparative genomics. There are a number of works concerning this problem in the literature, but they generally do not take into account the length of the operations (i.e. the number of genes affected by the operations). Since it has been observed that short operations are prevalent in the evolution of some species, algorithms that efficiently solve this problem in the special case of short operations are of interest. Results: In this paper, we investigate the problem of sorting a signed permutation by short operations. More precisely, we study four flavors of this problem: (i) the problem of sorting a signed permutation by reversals of length at most 2; (ii) the problem of sorting a signed permutation by reversals of length at most 3; (iii) the problem of sorting a signed permutation by reversals and transpositions of length at most 2; and (iv) the problem of sorting a signed permutation by reversals and transpositions of length at most 3. We present polynomial-time solutions for problems (i) and (iii), a 5-approximation for problem (ii), and a 3-approximation for problem (iv). Moreover, we show that the expected approximation ratio of the 5-approximation algorithm is not greater than 3 for random signed permutations with more than 12 elements. Finally, we present experimental results that show that the approximation ratios of the approximation algorithms cannot be smaller than 3. In particular, this means that the approximation ratio of the 3-approximation algorithm is tight.During evolution, global mutations may alter the order and the orientation of the genes in a genome. Such mutations are referred to as rearrangement events, or simply operations. In unichromosomal genomes, the most common operations are reversals, which a10117CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2014/04718-6]CNPq [303947/2008-0, 477692/2012-5]CNPq [477692/2012-5, 306730/2012-0, 483370/2013-4]FAPESP [2013/08293-7]SEM INFORMAÇÃO2014/04718-6; 2013/08293-7303947/2008-0; 477692/2012-5; 306730/2012-0; 477692/2012-5; 483370/2013-
An Empirical Mode Decomposition Approach for Multiple Broken Rotor Bars Detection in Three-Phase Induction Motors at No-Load Condition
This paper presents an empirical mode decomposition (EMD) approach for multiple broken rotor bars detection in squirrel cage induction motors running at no-load condition, using the resultant magnetic flux density measured by a Hall Effect sensor installed between two stator slots of the electrical machine. Usually, the traditional motor current signature analysis (MCSA) has produced many cases of false indications related to, among other reasons, incorrect speed estimation, operation at low load (low slip) and nonadjacent broken bars. This study has investigated the application of the EMD technique in the signal collected from the Hall sensor, in order to detect broken rotor bars for an induction motor running at very low slip and subjected to adjacent and nonadjacent broken bars. The present approach has been validated from some experiments carried out by a 7.5 kW induction motor fed by a sinusoidal power supply in the laboratory
Correlação entre a Clearance da Creatinina Estimada e a Taxa de Filtração Glomerular Estimada nos Doentes Muito Idosos e Erros de Prescrição dos Antibióticos: Um Estudo de Coorte
Introduction: Determination of renal function is particularly important when prescribing antibiotics to elderly patients. This study aims to determine the correlation between estimated creatinine clearance and the estimated glomerular filtration rate, for a hospitalized population of very elderly patients, and to audit antibiotic prescribing errors.
Material and methods: Retrospective cohort study of all patients ≥ 80 years hospitalized with antibiotic. Creatinine clearance was calculated using Cockcroft-Gault equation and estimated glomerular filtration rate by Modification of Diet in Renal Disease Study and Chronic Kidney Disease Epidemiology Collaboration equations. Dosing errors were determined through adjustment of daily define dose to renal function.
Results: The study included 589 patients. The correlation of Cockcroft-Gault with Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration was r = 0.98 and 0.96 for the minimum serum creatinine, and 0.97 and 0.93 for the maximum serum creatinine. Based on Cockcroft-Gault, there were errors in the daily defined dose in 45% in the minimum serum creatinine, and 52% in the maximum serum creatinine day. There was a discrepancy in the recording of errors of 14% to 16% when Cockcroft-Gault was compared with Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration.
Discussion: There was a good correlation of Cockcroft-Gault with the estimated glomerular filtration rate by Modification of Diet in Renal Disease or Chronic Kidney Disease Epidemiology Collaboration. Regardless of the equation used to estimate renal function there was a high rate of antibiotic dosing errors documented in this population.
Conclusion: This study supports the maintenance of the Cockcroft-Gault equation for drug dosing in the very elderly population. Further studies are needed to investigate underlying causes of prescribing errors.Introdução: A determinação da função renal é particularmente importante na prescrição de antibióticos em doentes idosos. O objetivo deste estudo é correlacionar a clearance de creatinina com a taxa de filtração glomerular estimada, numa população hospitalizada de doentes muito idosos, e auditar os erros de prescrição antibiótica. Material e Métodos: Coorte retrospetivo de todos os doentes ≥ 80 anos hospitalizados com antibioterapia prescrita. A clearance de creatinina foi calculada através da equação Cockcroft-Gault, e a filtração glomerular estimada através das equações Modification of Diet in Renal Disease e Chronic Kidney Disease Epidemiology Collaboration. Os erros de prescrição foram determinados pelo ajuste da dose diária definida à função renal. Resultados: Foram incluídos 589 doentes. A correlação da Cockcroft-Gault com Modification of Diet in Renal Disease e Chronic Kidney Disease Epidemiology Collaboration foi r = 0,98 e 0,96 para a creatinina sérica mínima, e 0,97 e 0,93 para a creatinina sérica máxima. Com base na Cockcroft-Gault, a taxa de erro na dose diária definida foi 45% no dia da creatinina sérica mínima e 52% no dia da creatinina sérica máxima. Quando a Cockcroft-Gault foi comparada com a Modification of Diet in Renal Disease e a Chronic Kidney Disease Epidemiology Collaboration houve uma discrepância no registo de erros de 14% a 16%, respetivamente. Discussão: Verificou-se uma boa correlação entre a Cockcroft-Gault e as equações que calculam a filtração glomerular: Modification of Diet in Renal Disease ou Chronic Kidney Disease Epidemiology Collaboration. Independentemente da equação utilizada para estimar a função renal, foi documentada uma taxa elevada de erros na dose de antibióticos prescrita nesta população. Conclusão: Este estudo reforça a manutenção do uso da equação de Cockcroft-Gault para calcular a dose adequada de antibióticos na população muito idosa. Mais estudos são necessários para investigar as causas subjacentes aos erros de prescrição.info:eu-repo/semantics/publishedVersio
As Origens de uma Etnosociologia Combativa nas Fronteiras Coloniais
Resenha:
BOURDIEU, Pierre; SAYAD, Abdelmalek. El desarraigo: la violencia del capitalismo en una sociedad rural. Buenos Aires, SigloVeintiuno Editores, 2017
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