Formal verification of a group membership protocol using model checking

The development of safety-critical embedded applications in domains such as automotive or avionics is an exceedingly challenging intellectual task. This task can, however, be significantly simplified through the use of middleware that offers specialized fault-tolerant services. This middleware must provide a high assurance level that it operates correctly. In this paper, we present a formal verification of a protocol for one such service, a Group Membership Service, using model checking. Through this verification we discovered that although the protocol specification is correct, a previously proposed implementation is not

A survey on asset allocation in the portuguese real estate market

Most important academic theoretical developments in finance and investment have been transferred to widespread practical use, especially in the more efficient securities markets. Real estate investment research has followed these developments, with a lag of about 20 years, but to some extent, common practice of asset allocation in a property portfolio still relies a lot on a qualitative and subjective personal judgment. To assess the reality and extent of this situation among the institutional property investors operating in the Portuguese market, a study based on a survey among a reference group of managers of large real estate portfolios was developed. This includes real estate fund management societies, pension funds and significant real property investment companies. The survey covers management decision-making practices, use of specific information, indices and databases, the role of appraisal, and the use of quantitative models regarding performance measurement, benchmarking and optimization of asset allocation. The aim is to establish the real gap between theory and practice. Research design is presented and justified against economic reality, and recent related and similar studies

Influence of the iron content on the solidification behaviour of cast aluminium bronze used in marine applications

The effect of iron addition to Cu-Al-Ni alloys (in the zone of the chemical composition of commercial aluminium bronze) has been studied. The quaternary alloys were melted from a base Cu-Al-Ni alloy with iron additions up to ~6 at.%. Simultaneous Differential Thermal Analysis and Termogravimetry (DSC/TGA) and isothermal homogenisation with rapid cooling have been employed to determine the equilibrium phases at different temperatures and the existing invariant reactions. The alloys were observed by Optical Microscopy (OP) and by Scanning Electron Microscopy (SEM). The chemical analysis of the phases has been determined by Energy-Dispersive Spectroscopy (EDS). The results obtained allow the determination of the effect of the iron content in the sequence of phase formation. The chemical compositions of the phases obtained are compared with the same phases in the commercial alloys, with other alloying elements being present. The effect of iron content on the “liquidus” temperature and phase compositions of the invariant reactions detected, in the range of compositions studied, are presented

Cidadania e cidade educadora: problematizando discursos presentes em ?manuais? de educa??o integral

This analysis, based on the contributions of the Cultural Studies in Education and the studies developed by Michel Foucault, focuses on problematizing the discourses on Integral Education present in ?manuals? used in teacher training. Such manuals are understood as books that bring essential concepts of a particular subject and, through these, seek to guide the actions of those who hold them. For this reason, the following works have been defined as material for analysis: Educa??o brasileira e(m) tempo integral (COELHO; CAVALIERE, 2002), Educa??o Integral no Brasil (GADOTTI, 2009), Educa??o Integral, Educa??o Cidad?: fundamentos e pr?ticas (ANTUNES; PADILHA, 2010) e Educa??o Integral em Tempo Integral: estudos e experi?ncias em processo (COELHO, 2009). Therefore, working with the concepts of discourse and governance, it was questioned which discourses are legitimated when talking about Integral Education, which advice/prescriptions are prioritized to guide the conduct of teachers and how these discourses promote a particular methodology for the operationalization of Education Integral. From the reading of these works, it was possible to observe the recurrence of discourses related to the promotion of citizenship and to the operationalization of an educating city. Thus, we defined the following units of analysis: a) concepts of Integral Education as a principle for the development of Citizenship; b) Integral Education as a living and learning experience articulated with projects in an Educating City. From the analysis, it was revealed that the pedagogic practices of education in citizenship, through relations of power and knowledge, establish supposed truths for subjecting individuals through promises of emancipation and ?salvation?. It was found that the institution of an Educating City has emerged through a City Pedagogy, in which subjects, as active and engaged citizens, assume responsibility for educating in the scenario of a social project, taking as its premise a supposed citizen education.Esta an?lise, a partir das contribui??es dos Estudos Culturais em Educa??o e dos estudos desenvolvidos por Michel Foucault, tem como foco problematizar os discursos sobre Educa??o Integral presentes em ?manuais? utilizados na forma??o docente. Tais manuais s?o entendidos como livros que apresentam no??es essenciais sobre um determinado assunto e que, atrav?s destas, buscam orientar a a??o de quem os det?m. Por essa raz?o, foram definidas as seguintes obras como material de an?lise: Educa??o brasileira e(m) tempo integral (COELHO; CAVALIERE, 2002), Educa??o Integral no Brasil (GADOTTI, 2009), Educa??o Integral, Educa??o Cidad?: fundamentos e pr?ticas (ANTUNES; PADILHA, 2010) e Educa??o Integral em Tempo Integral: estudos e experi?ncias em processo (COELHO, 2009). Para tanto, operando com os conceitos de discurso e governamento, questionam-se que discursos s?o legitimados para falar sobre a Educa??o Integral, quais conselhos/prescri??es s?o priorizadas para orientar as condutas dos professores e como esses discursos promovem uma determinada metodologia de operacionaliza??o da Educa??o Integral. A partir da leitura das obras, foi poss?vel observar a recorr?ncia de discursos relativos ? promo??o da cidadania e ? operacionaliza??o de uma cidade educadora. Desse modo, foram definidas as seguintes unidades de an?lise: a) concep??es de Educa??o Integral como princ?pio para o desenvolvimento da cidadania; b) Educa??o Integral como viv?ncia e experi?ncia de aprendizagem articulada a projetos em uma Cidade Educadora. A partir das an?lises, foi poss?vel perceber que as pr?ticas pedag?gicas de educa??o em cidadania, atrav?s de rela??es de poder e saber, estabelecem supostas verdades para subjetivar os sujeitos atrav?s de promessas de emancipa??o e ?salva??o?. Constatou-se que a institui??o de uma Cidade Educadora tem se configurado por meio da Pedagogia de Cidade, na qual os sujeitos, como cidad?os ativos e comprometidos, assumem a responsabilidade educativa no conjunto de um projeto social, tendo como premissa uma suposta educa??o cidad?

Unique life sciences research facilities at NASA Ames Research Center

The Life Science Division at NASA's Ames Research Center has a suite of specialized facilities that enable scientists to study the effects of gravity on living systems. This paper describes some of these facilities and their use in research. Seven centrifuges, each with its own unique abilities, allow testing of a variety of parameters on test subjects ranging from single cells through hardware to humans. The Vestibular Research Facility allows the study of both centrifugation and linear acceleration on animals and humans. The Biocomputation Center uses computers for 3D reconstruction of physiological systems, and interactive research tools for virtual reality modeling. Psycophysiological, cardiovascular, exercise physiology, and biomechanical studies are conducted in the 12 bed Human Research Facility and samples are analyzed in the certified Central Clinical Laboratory and other laboratories at Ames. Human bedrest, water immersion and lower body negative pressure equipment are also available to study physiological changes associated with weightlessness. These and other weightlessness models are used in specialized laboratories for the study of basic physiological mechanisms, metabolism and cell biology. Visual-motor performance, perception, and adaptation are studied using ground-based models as well as short term weightlessness experiments (parabolic flights). The unique combination of Life Science research facilities, laboratories, and equipment at Ames Research Center are described in detail in relation to their research contributions

Digital soil mapping for soil class prediction in a dry forest of Minas Gerais, Brazil.

Investment on soil survey has become scarce over the past decades. Digital Soil Mapping (DSM) techniques emerged as an economic alternative to produce soil maps. We applied a classification tree algorithm to predict soil suborders in a tropical dry forest area with 102 km2 in the north of Minas Gerais state, Brazil. We tested environmental covariates with different spatial resolutions as predictors, and used 361 observations to train the model and 64 independent observations to validate the map. Prediction models included three decision trees and one logistic regression model. The results showed that freely available environmental covariates with coarser spatial resolution can produce as good or better suborder predictions than more expensive covariates with finer resolution

Treinamento em mapeamento digital de solos: carbono no Rio de Janeiro, Brasil.

No período de 24 a 28 de setembro de 2012 foi realizado na Embrapa Solos, Rio de Janeiro, RJ, o Curso de Capacitación en Cartografía Digital de Suelos, que contou com a presença de 17 pedólogos de 17 países da América Latina e Caribe. O objetivo do curso foi capacitar os pedólogos em mapeamento digital de solos utilizando os softwares livres SAGA, R e RStudio. No curso realizou-se, como estudo de caso, o mapeamento do carbono orgânico do solo na camada 0-10 cm no município de Campos dos Goytacazes, RJ, Brasil. Apresentamos as etapas de treinamento realizadas durante o curso, incluindo a preparação de dados de solos e covariáveis ambientais, análise exploratória de dados, modelagem espacial, produção de mapas e validação dos resultados obtidos. A combinação dos softwares livres SAGA, R e RStudio mostrou-se bastante flexível para a realização do curso e mapeamento digital de carbono orgânico do solo, sendo recomendada para outros cursos e projetos de mapeamento digital de solos. A estrutura do curso mostrou-se adequada também para implementação através de ensino à distância (resultados apresentados em outro trabalho nestes anais). Para êxito de cursos e projetos similares, salientamos a importância da experiência prévia dos participantes com conceitos e técnicas de pedologia, estatística, geoprocessamento e linguagem de programação, bem como da existência de um banco de dados de solos organizado e disponível

Treinamento presencial e à distância em mapeamento digital de solos para latinoamericanos.

A produção de informação de solos é demorada e custosa, sendo essa informação essencial para a agricultura, gerenciamento dos recursos naturais, simulações dos efeitos das mudanças climáticas, entre outros. O mapeamento digital de solos (MDS) tem avançado como metodologia complementar ao levantamento clássico de solos buscando soluções rápidas e eficazes para o mapeamento de solos, utilizando dados auxiliares (covariáveis) e métodos estatísticos e matemáticos. Nesse contexto, a Embrapa Solos realizou, através de um acordo firmado com a Organização das Nações Unidas para a Alimentação e a Agricultura (FAO), cursos de capacitação em MDS para técnicos de 18 países da América Latina e Caribe (LAC). Foram oferecidos dois cursos presenciais nas instalações da Embrapa Solos, no Rio de Janeiro, RJ, Brasil, e um curso à distância, onde foram empregados softwares livres para preparação e análise de dados (SAGA, R e RStudio), criação de vídeo (CamStudio e iSpring) e ensino à distância (Moodle). Os cursos tiveram conteúdo teórico-prático, tendo sido realizado como estudo de caso no primeiro curso presencial o mapeamento digital de carbono do solo (cujos resultados são apresentados em outro trabalho nestes anais). Este trabalho apresenta a experiência desenvolvida pela Embrapa Solos e os principais resultados do esforço para capacitar, presencialmente e à distância, técnicos de diferentes países da LAC em MDS

High-temperature corrosion performance of austenitic stainless steels type AISI 316L and AISI 321H, in molten solar salt

ABSTRACT: The corrosion rates of AISI 316L and AISI 321H austenitic stainless steel, immersed in a stagnant isothermal mixture of 60% NaNO3 and 40% KNO3 molten salt at 550 degrees C in atmospheric air are 8.6 and 9.0 mu m/yr, respectively. The corrosion mechanism was proposed by recording the weight changes of the steel coupons at different time intervals up to 3000 h, and by the characterization of multilayer oxide scales formed on the steel surface. Multilayers made of different oxides, mainly Fe2O3 and Fe3O4, are the principal scale products. At 3000 h, the thickness of the scale layer formed on AISI 321H (7.5 +/- 2.9 mu m) is slightly higher than the one formed at the AISI 316L (6.9 +/- 2.1 mu m). This small difference might reflect the partial spallation of the corrosion layer on AISI 321H, which is seen for times longer than 1000 h. A minimal change of the composition of the molten nitrate salt is observed in time and is predominantly due to the appearance of soluble chromate products and nitrite compounds (0.004 wt% and 1.4 wt% at 3000 h, respectively). The observed corrosion behaviour of these alloys shows that they are good candidate for usage as containers of molten nitrate salts in the thermal energy storage (TES) system for a CSP plant.info:eu-repo/semantics/publishedVersio

Soil classification from visible/near-infrared diffuse reflectance spectra at multiple depths.

Abstract : Visible/near-infrared diffuse reflectance spectroscopy (VNIRS) offers an alternative to conventional analytical methods to estimate various soil attributes. However, the use of VNIRS in soil survey and taxonomic classification is still underexplored. We investigated the potential use of VNIRS to classify soils in a region with variable soils, geology, and topography in southeastern Brazil. We combined principal component (PC) analysis, and multinomial logistic regression to classify 291 soils at the levels of suborder (second highest), and suborder with textural classification (STC), described in the field according to the Brazilian Soil Classification System. Soil visible/near-infrared (400-2500 nm) spectra were collected from three depth intervals (0-20, 40-60, and 80-100 cm), and combined in sequence to compose a pseudo multi-depth spectral curve, which was used to derive the classification models. The percent of correctly classified soils at the suborder level was 79% using 20 PCs, and 96% using 30 PCs. At the STC level, soils were correctly classified in 100%, and 78% of the cases using 20, and 30 PCs, respectively. Given the inherent complexity and variability within soil taxonomic groups, and in contrast the similarity among different groups, combining spectral data from different depths in multivariate classification offered a simple and inexpensive solution to adequately distinguish soils. This novel approach could improve soil classification and survey in a cost-efficient manner, supporting sustainable use, and management of tropical soils