Certified Roundoff Error Bounds using Bernstein Expansions and Sparse Krivine-Stengle Representations

Floating point error is an inevitable drawback of embedded systems implementation. Computing rigorous upper bounds of roundoff errors is absolutely necessary to the validation of critical software. This problem is even more challenging when addressing non-linear programs. In this paper, we propose and compare two new methods based on Bernstein expansions and sparse Krivine-Stengle representations, adapted from the field of the global optimization to compute upper bounds of roundoff errors for programs implementing polynomial functions. We release two related software package FPBern and FPKiSten, and compare them with state of the art tools. We show that these two methods achieve competitive performance, while computing accurate upper bounds by comparison with other tools.Comment: 20 pages, 2 table

Index-2 hybrid DAE: a case study with well-posedness and numerical analysis

In this work, we study differential algebraic equations with constraints defined in a piecewise manner using a conditional statement. Such models classically appear in systems where constraints can evolve in a very small time frame compared to the observed time scale. The use of conditional statements or hybrid automata are a powerful way to describe such systems and are, in general, well suited to simulation with event driven numerical schemes. However, such methods are often subject to chattering at mode switch in presence of sliding modes, or can result in Zeno behaviours. In contrast, the representation of such systems using differential inclusions and method from non-smooth dynamics are often closer to the physical theory but may be harder to interpret. Associated time-stepping numerical methods have been extensively used in mechanical modelling with success and then extended to other fields such as electronics and system biology. In a similar manner to the previous application of non-smooth methods to the simulation of piecewise linear ODEs, non-smooth event-capturing numerical scheme are applied to piecewise linear DAEs. In particular, the study of a 2-D dynamical system of index-2 with a switching constraint using set-valued operators, is presented

Index-2 hybrid DAE: a case study with well-posedness and numerical analysis

International audienceIn this work, we study differential algebraic equations with constraints defined in a piecewise manner using a conditional statement. Such models classically appear in systems where constraints can evolve in a very small time frame compared to the observed time scale. The use of conditional statements or hybrid automata are a powerful way to describe such systems and are, in general, well suited to simulation with event driven numerical schemes. However, such methods are often subject to chattering at mode switch in presence of sliding modes, or can result in Zeno behaviours. In contrast, the representation of such systems using differential inclusions and method from non-smooth dynamics are often closer to the physical theory but may be harder to interpret. Associated time-stepping numerical methods have been extensively used in mechanical modelling with success and then extended to other fields such as electronics and system biology. In a similar manner to the previous application of non-smooth methods to the simulation of piecewise linear ODEs, non-smooth event-capturing numerical scheme are applied to piecewise linear DAEs. In particular, the study of a 2-D dynamical system of index-2 with a switching constraint using set-valued operators, is presented

Index-2 hybrid DAE: a case study with well-posedness and numerical analysis

In this work, we study differential algebraic equations with constraints defined in a piece-wise manner using a conditional statement. Such models classically appear in systems where constraints can evolve in a very small time frame compared to the observed time scale. The use of conditional statements or hybrid automata are a powerful way to describe such systems and are, in general, well suited to simulation with event driven numerical schemes. However, such methods are often subject to chattering at mode switch in presence of sliding modes, and can result in Zeno behaviours. In contrast, the representation of such systems using differential inclusions and method from non-smooth dynamics are often closer to the physical theory but may be harder to interpret. Associated time-stepping numerical methods have been extensively used in mechanical modelling with success and then extended to other fields such as electronics and system biology. In a similar manner to the previous application of non-smooth methods to the simulation of piece-wise linear ODEs, we want to apply non-smooth numerical scheme to piece-wise linear DAEs. In particular, the study of a 2-D dynamical system of index-2 with a switching constraint using set-valued operators, is presented

Die Darstellung atomaren Wasserstoffs bei höheren Drucken

Pure and dry hydrogen is partially dissociated into atoms on a tungsten filament at 2500° K at pressures of about 20 mm Hg. This filament is mounted in a quartz tube (diam.17 mm) the walls of which are covered with an anticatalytic layer. The tube is surrounded by a water jacket. The mixture of atomic and molecular hydrogen is hereby cooled to room temperature. A stream of cold hydrogen with a constant content of some percentage of atoms during several hours is obtainable for preparatory purposes

Actions for tuberculosis control in Brazil : evaluation of primary care

Objetivo: Descrever e avaliar os fatores associados ao conjunto de ações para o controle da tuberculose (TB) na atenção básica (AB) nas cinco macrorregiões brasileiras. Métodos: Trata-se de um estudo transversal de base em serviço com dados obtidos a partir do segundo ciclo do Programa Nacional de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ-AB). O desfecho foi construído a partir de um conjunto de itens que caracterizam a realização de ações para o cuidado no controle e tratamento da TB nas unidades básicas de saúde (UBSs). Os dados foram analisados por meio do teste do χ2 e da regressão de Poisson com variância robusta. Resultados: A prevalência nacional do conjunto de ações para controle da TB foi de 17,22%, sendo que as macrorregiões Nordeste (11,18%) e Norte (12,15%) tiveram o pior desempenho. Os resultados principais apontam que houve associação da presença do conjunto de ações para o controle da TB com as UBSs que realizam ações educativas para TB [razão de prevalência — RP = 1,53 (intervalo de confiança de 95% — IC95% 1,45 – 1,62)], sorologia para HIV [RP = 1,68 (IC95% 1,11 – 2,54)], possuem sala de acolhimento [RP = 1,61 (IC95% 1,46 – 1,79)] e atividades de educação permanente [RP = 1,73 (IC95% 1,54 – 1,95)]. Conclusão: Os resultados demonstram fragilidade nas estruturas e no processo de trabalho da AB em relação ao controle da TB em todas as regiões brasileiras.Objective: To describe and evaluate the factors associated with actions for the control of tuberculosis (TB) in primary care (PC) in the five Brazilian macroregions. Methods: This cross-sectional study was carried out with data from the second cycle of the National Program for Improving Access to and Quality of Primary Care. The outcome of the study was constructed based on a set of items that were considered essential for the treatment and control of tuberculosis in Primary Care Units (PCUs). Data were analyzed using the χ2 test and Poisson regression with robust variance. Results: The national prevalence of the set of items to control tuberculosis was 17.22%. The Northeast (11.18%) and North (12.15%) had the worst performance. The main results indicate association with this outcome for PCUs performing educational actions for TB (PR = 1.53; 95%CI 1.45 – 1.62), those performing HIV serology (PR = 1.68; 95%CI 1.11 – 2.54), those that have a reception room (PR = 1.61; 95%CI 1.46 – 1.79) and those performing continuing education activities (PR = 1.73; 95%CI 1.54 – 1.95). Conclusion: The results show a weakness in the structures and in the work process of PC in relation to the control of tuberculosis in all Brazilian regions

INTERVENÇÃO MEDIADA POR PARES COMO ESTRATÉGIA DE INCLUSÃO DE CRIANÇAS COM TRANSTORNO DE ESPECTRO AUTISTA

O Grupo Pesquisador em Educação Ambiental Comunicação e Arte da Universidade Federal de Mato Grosso realizou, no Quilombo de Mata Cavalo, em parceria com a comunidade quilombola e a Escola Estadual Quilombola “Tereza Conceição de Arruda' (E.E.T.C.A.) o projeto de extensão: Escolas Sustentáveis no Quilombo de Mata Cavalo. Mata Cavalo está localizado na zona rural do Município de Nossa Senhora do Livramento, distante aproximadamente 55 km de Cuiabá. Participaram deste projeto professoras, estudantes de pós-graduação e graduação ligados ao GPEA/UFMT, Professores, estudantes do Ensino Fundamental II, Ensino Médio e da educação de jovens e adultos (EJA) da E.E.T.C.A. e moradores do quilombo. O projeto teve como objetivo realizar processo formativo em Educação Ambiental com a comunidade escolar e seu entorno, com ênfase na construção de espaços educadores sustentáveis. O projeto foi desenvolvido durante 4 meses e culminou com a construção da Casa da Cultura, Projeto Ambiental Escolar Comunitário escolhido pelas comunidades escolar e do entorno

Acclimatization to cold and frost-injury in canola

O objetivo deste trabalho foi avaliar a influência da aclimatação ao frio sobre o dano causado pela geada em diferentes estádios fenológicos de genótipos de canola. Foram realizados cinco experimentos em ambiente controlado, em 2006, 2007 e 2008. Os fatores avaliados foram: genótipos, aclimatação (com; sem), intensidades de geada, estádios de desenvolvimento de plantas, regimes de aclimatação e regimes de geada. As variáveis avaliadas foram: queima de folhas, massa de matéria seca, estatura de plantas, duração de subperíodo, componentes de rendimento e rendimento de grãos. A aclimatação ao frio, antes da geada, resultou em menor queima de folhas e maior massa de matéria seca, em comparação a plantas não aclimatadas. As geadas foram prejudiciais a partir de -6°C no início do ciclo de desenvolvimento, principalmente em plantas não aclimatadas, e a partir de -4ºC na floração, com redução do número de síliquas e do número de grãos por síliqua. A aclimatação após as geadas não contribuiu para a tolerância da canola a esse evento. Geadas consecutivas não acarretaram maior prejuízo à canola. A aclimatação de plantas de canola antes da geada reduz os danos, principalmente quando a geada ocorre no início do desenvolvimento das plantas.The objective of this work was to evaluate the influence of cold acclimatization on frost damage at different phenological stages of canola genotypes. Five experiments were carried out under controlled conditions, in 2006, 2007, and 2008. The evaluated factors were: genotypes, acclimatization (with; without), frost gradient, plant developmental stages, acclimatization regimes and frost regimes. The evaluated variables were: leaf scorching symptoms, dry weight, plant height, length of subperiod, yield components and grain yield. The acclimatization before frost resulted in lesser leaf scorching symptoms and higher dry matter in comparison to plants not acclimated. Frosts were harmful from -6°C in early plant development stage, mainly in nonacclimated plants, and from -4ºC at flowering, reducing the number of pods and the number of grains per pod. Acclimatization after frost did not contribute to the tolerance of canola to frost. Consecutive frosts caused no greater impairment to canola. The canola acclimatization before frost reduces damage caused by it, mainly when the frost occur in the initial plant development stages

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161