853 resultados para on-line
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This is the final report on reproducibility@xsede, a one-day workshop held in conjunction with XSEDE14, the annual conference of the Extreme Science and Engineering Discovery Environment (XSEDE). The workshop's discussion-oriented agenda focused on reproducibility in large-scale computational research. Two important themes capture the spirit of the workshop submissions and discussions: (1) organizational stakeholders, especially supercomputer centers, are in a unique position to promote, enable, and support reproducible research; and (2) individual researchers should conduct each experiment as though someone will replicate that experiment. Participants documented numerous issues, questions, technologies, practices, and potentially promising initiatives emerging from the discussion, but also highlighted four areas of particular interest to XSEDE: (1) documentation and training that promotes reproducible research; (2) system-level tools that provide build- and run-time information at the level of the individual job; (3) the need to model best practices in research collaborations involving XSEDE staff; and (4) continued work on gateways and related technologies. In addition, an intriguing question emerged from the day's interactions: would there be value in establishing an annual award for excellence in reproducible research? Overview
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Na primeira parte do trabalho, foram investigados materiais ativos para eletro-oxidar etanol e acetaldeído seletivos para a rota C2 (Carbono 2) e, também, ativos para eletro-oxidar hidrogênio molecular, visando a aplicação em células a combustível de hidrogênio indireto. Neste tipo de célula, um processador de combustível externo desidrogena o etanol e os produtos desta reação, contendo H2, acetaldeído e, possivelmente, etanol residual, são direcionados para alimentar o ânodo. Neste sentido, o eletrocatalisador anódico pode ser ativo para a eletro-oxidação de etanol residual, bem como acetaldeído, mas este deve catalisar a reação via C2 com o objetivo de evitar a formação de espécies que envenenam a superfície catalítica (CO ou CHx), ou seja, a ligação C-C deve permanecer intacta. Os eletrocatalisadores bimetálicos foram formados por M/Pt/C (onde M = W, Ru ou Sn) e os produtos reacionais foram analisados por DEMS On-line. Os resultados mostraram que Ru/Pt/C e Sn/Pt/C apresentaram maiores taxas de reação global, no entanto, eles não foram seletivos. Por outro lado, W2/Pt3/C foi mais seletivo para a rota C2, dada a não formação de CH4 e CO2. Além disso, este material também foi ativo e estável para a eletro-oxidação de H2, mesmo na presença de acetaldeído, o que o torna um potencial catalisador para aplicação no ânodo de células a combustível de hidrogênio indireto. Na segunda parte do trabalho, o objetivo foi relacionado com o estudo de eletrocatalisadores seletivos para a rota C1 (Carbono 1). A oxidação eletroquímica do etanol e de seus produtos reacionais foram investigados por DEMS on-line em temperatura ambiente e intermediária (245oC). Para temperatura ambiente, utilizou-se solução aquosa de ácido sulfúrico (H2SO4) e, para temperatura intermediária, utilizou-se ácido sólido (CsH2PO4) como eletrólito. Os eletrocatalisadores investigados foram formados por SnOxRuOx-Pt/C e Pt/C. Em temperatura ambiente, os resultados de polarização potenciodinâmica mostraram uma maior atividade eletrocatalítica para o material SnOxRuOx-Pt/C, com eficiência de corrente para formação de CO2 de 15,6% contra 15,2% para Pt/C, sob condições estagnantes, sem controle por transporte de massa. O stripping de resíduos reacionais, após a eletro-oxidação de etanol bulk, sob condições de fluxo, mostraram o acúmulo de espécies com 1 átomo de carbono (CO e CHx) que causam o bloqueio dos sítios ativos e são oxidadas eletroquimicamente somente em mais altos potenciais (ca. 1,0 V). Por outro lado, as curvas de polarização a 245oC mostraram maiores valores de eficiências de correntes para formação de CO2 (45% para Pt/C em ambos potenciais 0,5 V e 0,8 V contra 36% e 50% para SnOxRuOx-Pt/C em 0,5 V e 0,8 V respectivamente) quando comparado com os valores obtidos em temperatura ambiente, mas com atividades similares para SnOxRuOx-Pt/C e Pt/C. Para ambos os eletrocatalisadores, os estudos de espectrometria de massas a 245oC evidenciaram que as rotas eletroquímicas ocorrem em paralelo com rotas puramente químicas, envolvendo catálise heterogênea, de decomposição do etanol, produzindo H2 e CO2 como produtos majoritários.
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A range of catalysts based on Pd nanoparticles supported on inorganic supports such as BETA and ZSM-5 zeolites, a silicoaluminophosphate molecular sieve (SAPO-5) and γ-alumina as a standard support have been tested for the total oxidation of naphthalene (100 ppm, total flow 50 ml/min) showing a conversion to carbon dioxide of 100% between 165 and 180 °C for all the analysed catalysts. From the combined use of zeolites with PVP polymer protected Pd based nanoparticles, enhanced properties have been found for the total abatement of naphthalene in contrast with other kinds of catalysts. A Pd/BETA catalyst has been demonstrated to have excellent activity, with a high degree of stability, as shown by time on line experiments maintaining 100% conversion to CO2 during the 48 h tested.
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An on-line survey of experts was conducted to solicit their views on policy priorities in the area of information and communication technologies (ICT) in the Caribbean. The experts considered the goal to “promote teacher training in the use of ICTs in the classroom” to be the highest priority, followed by goals to “reduce the cost of broadband services” and “promote the use of ICT in emergency and disaster prevention, preparedness and response.” Goals in the areas of cybercrime, e-commerce, egovernment, universal service funds, consumer protection, and on-line privacy rounded out the top 10. Some of the lowest ranked goals were those related to coordinating the management of infrastructure changes. These included the switchover for digital terrestrial television (DTT) and digital FM radio, cloud computing for government ICT, the introduction of satellite-based internet services, and the installation of content distribution networks (CDNs). Initiatives aimed at using ICT to promote specific industries, or specific means of promoting the digital economy, tended toward the centre of the rankings. Thus, a general pattern emerged which elevated the importance of focusing on how ICT is integrated into the broader society, with economic issues a lower priority, and concerns about coordination on infrastructure issues lower still.
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Amongst the opportunities for cross-cultural contact created by the burgeoning use of the Internet are those provided by electronic discussion lists. This study looks at what happens when language students venture out of the classroom (virtual or otherwise) to participate in on-line discussion groups with native speakers. Responses to messages and commentary by moderators and other participants on the (in) appropriateness of contributions allow us to determine what constitutes successful participation and to make suggestions regarding effective teaching strategies for this medium. A case study examines the threads started by four anglophone students of French when they post messages to a forum on the Web site of the French newspaper Le Monde. Investigation of these examples points to the ways in which electronic discussion inflects and is inflected by cultural and generic expectations. We suggest that successful participation on Internet fora depends on awareness of such cultural and generic mores and an ability to work within and/or with them. Teachers therefore need to find ways in which students can be sensitized to such issues so that their participation in such electronic discussion is no longer seen as linguistic training, but as engagement with a cultural practice.
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In developing neural network techniques for real world applications it is still very rare to see estimates of confidence placed on the neural network predictions. This is a major deficiency, especially in safety-critical systems. In this paper we explore three distinct methods of producing point-wise confidence intervals using neural networks. We compare and contrast Bayesian, Gaussian Process and Predictive error bars evaluated on real data. The problem domain is concerned with the calibration of a real automotive engine management system for both air-fuel ratio determination and on-line ignition timing. This problem requires real-time control and is a good candidate for exploring the use of confidence predictions due to its safety-critical nature.
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This article focuses on the English language experiences of a group of pre-sessional students, an under-represented group in the literature on language and education. In particular, it investigates the opportunities that such students have to use English outside the classroom, shown to be a key factor in student satisfaction with their study abroad experience. Drawing on data from questionnaires, interviews and on-line diaries, we show that students have a variety of opportunities to use English; however, these opportunities may require students to engage in complex negotiations right from the beginning of their sojourn in the UK. Micro-analysis of the data shows that agency is a key construct in understanding students' representations of their English encounters as they begin their lives in the UK. The article concludes with some suggestions as to how pre-sessional courses may develop students' linguistic and socio-cultural skills in order that they may interact successfully in English outside the classroom. © 2011 Taylor &Francis.
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Professional standards of ethics proclaim the core values of a profession, describe expected professional duties and responsibilities, and provide a framework for ethical practice and ethical decision-making. The purpose of this mixed, quantitative and qualitative, survey study was to examine HRD professionals' perceptions about the AHRD Standards on Ethics and Integrity, how HRD professionals used the Standards for research and decision-making, and the extent to which the Standards provided guidance for ethical decision-making. Through an on-line survey instrument, 182 members of AHRD were surveyed. The open-ended questions were analyzed using thematic analysis to expand on, inform, and support the quantitative findings. The close-ended questions were analyzed with frequency distributions, descriptive statistics, cross tabulations, and Spearman rank correlations. The results showed a significant relationship between (a) years of AHRD membership and level of familiarity with the Standards, (b) years of AHRD membership and use of the Standards for research, and (c) level of familiarity with the Standards and use of the Standards for research. There were no significant differences among scholars, scholar practitioners, practitioners, and students regarding their perceptions about the Standards. The results showed that the Standards were not well known or widely used. Nevertheless, the results indicated overall positive perceptions about the Standards. Seventy percent agreed that the Standards provided an appropriate set of ethical principles and reflected respondents' own standards of conduct. Seventy-eight percent believed that the Standards were important for defining HRD as a profession and 54% believed they were important for developing a sense of belonging to the HRD profession. Fifty-one percent believed the Standards should be enforceable and 61% agreed members should sign the membership application form showing willingness to adhere to the Standards. Seventy-seven percent based work-related ethical decisions on personal beliefs of right and wrong and 56% on established professional values and rules of right and wrong. The findings imply that if the professional standards of ethics are to influence the profession, they should be widely publicized and discussed among members, they should have some binding power, and their use should be encouraged.
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The purpose of this research is design considerations for environmental monitoring platforms for the detection of hazardous materials using System-on-a-Chip (SoC) design. Design considerations focus on improving key areas such as: (1) sampling methodology; (2) context awareness; and (3) sensor placement. These design considerations for environmental monitoring platforms using wireless sensor networks (WSN) is applied to the detection of methylmercury (MeHg) and environmental parameters affecting its formation (methylation) and deformation (demethylation). ^ The sampling methodology investigates a proof-of-concept for the monitoring of MeHg using three primary components: (1) chemical derivatization; (2) preconcentration using the purge-and-trap (P&T) method; and (3) sensing using Quartz Crystal Microbalance (QCM) sensors. This study focuses on the measurement of inorganic mercury (Hg) (e.g., Hg2+) and applies lessons learned to organic Hg (e.g., MeHg) detection. ^ Context awareness of a WSN and sampling strategies is enhanced by using spatial analysis techniques, namely geostatistical analysis (i.e., classical variography and ordinary point kriging), to help predict the phenomena of interest in unmonitored locations (i.e., locations without sensors). This aids in making more informed decisions on control of the WSN (e.g., communications strategy, power management, resource allocation, sampling rate and strategy, etc.). This methodology improves the precision of controllability by adding potentially significant information of unmonitored locations.^ There are two types of sensors that are investigated in this study for near-optimal placement in a WSN: (1) environmental (e.g., humidity, moisture, temperature, etc.) and (2) visual (e.g., camera) sensors. The near-optimal placement of environmental sensors is found utilizing a strategy which minimizes the variance of spatial analysis based on randomly chosen points representing the sensor locations. Spatial analysis is employed using geostatistical analysis and optimization occurs with Monte Carlo analysis. Visual sensor placement is accomplished for omnidirectional cameras operating in a WSN using an optimal placement metric (OPM) which is calculated for each grid point based on line-of-site (LOS) in a defined number of directions where known obstacles are taken into consideration. Optimal areas of camera placement are determined based on areas generating the largest OPMs. Statistical analysis is examined by using Monte Carlo analysis with varying number of obstacles and cameras in a defined space. ^
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In this paper the characteristics of the cyclical political polarization of the Spanish media system are defined. From this study, a prospective analysis raises doubts about this scenario remains unchanged because of the political and economic crisis. It seeks to define the role played by political and media actors in polarization focusing on the two legislatures where the tension reached higher levels (1993-1996 and 2004-2008) and compares it with the developments faced by them in the current economical and political context of crisis. To achieve these aims, it has been performed an analysis of media content (since 1993) and looked through primary sociological sources and the scientific literature about polarization. This is an exploratory, critical and descriptive case analysis.
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Advertising investment and audience figures indicate that television continues to lead as a mass advertising medium. However, its effectiveness is questioned due to problems such as zapping, saturation and audience fragmentation. This has favoured the development of non-conventional advertising formats. This study provides empirical evidence for the theoretical development. This investigation analyzes the recall generated by four non-conventional advertising formats in a real environment: short programme (branded content), television sponsorship, internal and external telepromotion versus the more conventional spot. The methodology employed has integrated secondary data with primary data from computer assisted telephone interviewing (CATI) were performed ad-hoc on a sample of 2000 individuals, aged 16 to 65, representative of the total television audience. Our findings show that non-conventional advertising formats are more effective at a cognitive level, as they generate higher levels of both unaided and aided recall, in all analyzed formats when compared to the spot.
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[EN]In this paper an architecture for an estimator of short-term wind farm power is proposed. The estimator is made up of a Linear Machine classifier and a set of k Multilayer Perceptrons, training each one for a specific subspace of the input space. The splitting of the input dataset into the k clusters is done using a k-means technique, obtaining the equivalent Linear Machine classifier from the cluster centroids...
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This dissertation investigates the acquisition of oblique relative clauses in L2 Spanish by English and Moroccan Arabic speakers in order to understand the role of previous linguistic knowledge and its interaction with Universal Grammar on the one hand, and the relationship between grammatical knowledge and its use in real-time, on the other hand. Three types of tasks were employed: an oral production task, an on-line self-paced grammaticality judgment task, and an on-line self-paced reading comprehension task. Results indicated that the acquisition of oblique relative clauses in Spanish is a problematic area for second language learners of intermediate proficiency in the language, regardless of their native language. In particular, this study has showed that, even when the learners’ native language shares the main properties of the L2, i.e., fronting of the obligatory preposition (Pied-Piping), there is still room for divergence, especially in production and timed grammatical intuitions. On the other hand, reaction time data have shown that L2 learners can and do converge at the level of sentence processing, showing exactly the same real-time effects for oblique relative clauses that native speakers had. Processing results demonstrated that native and non-native speakers alike are able to apply universal processing principles such as the Minimal Chain Principle (De Vincenzi, 1991) even when the L2 learners still have incomplete grammatical representations, a result that contradicts some of the predictions of the Shallow Structure Hypothesis (Clahsen & Felser, 2006). Results further suggest that the L2 processing and comprehension domains may be able to access some type of information that it is not yet available to other grammatical modules, probably because transfer of certain L1 properties occurs asymmetrically across linguistic domains. In addition, this study also explored the Null-Prep phenomenon in L2 Spanish, and proposed that Null-Prep is an interlanguage stage, fully available and accounted within UG, which intermediate L2 as well as first language learners go through in the development of pied-piping oblique relative clauses. It is hypothesized that this intermediate stage is the result of optionality of the obligatory preposition in the derivation, when it is not crucial for the meaning of the sentence, and when the DP is going to be in an A-bar position, so it can get default case. This optionality can be predicted by the Bottleneck Hypothesis (Slabakova, 2009c) if we consider that these prepositions are some sort of functional morphology. This study contributes to the field of SLA and L2 processing in various ways. First, it demonstrates that the grammatical representations may be dissociated from grammatical processing in the sense that L2 learners, unlike native speakers, can present unexpected asymmetries such as a convergent processing but divergent grammatical intuitions or production. This conclusion is only possible under the assumption of a modular language system. Finally, it contributes to the general debate of generative SLA since in argues for a fully UG-constrained interlanguage grammar.
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Mercury is not an essential element for plant or animal life and it is a potential environmental toxic because of its tendency to form covalent bonds with organic molecules and the high stability of the Hg-C bond. Reports estimate a total mercury concentration in natural waters ranging from 0.2 to 100 ng L-1. Due to this fact, highly sensitive methods are required for direct determination of such extremely low levels. In this work, a rapid and simple method was developed for separation and preconcentration of mercury by flow injection solid phase extraction coupled with on-line chemical vapour generation electrothermal atomic absorption spectrometry. The system is based on chelating retention of the analyte onto the mini column filled with a mesoporous silica functionalized with 1,5 bis (di-2-pyridyl) methylene thiocarbohydrazide. The main aim of this work was to develop a precise and accurate method for the determination of the Hg. Under the optima conditions and 120 s preconcentration time, the detection limit obtained was 0.009 μg L-1, with RSDs 3.7 % for 0.2 μg L-1, 4.8 % for 1 μg L-1 and enrichment factor 4, Furthermore, the method proposed has permitted the determination of Hg with a reduction in the analysis time, the sample throughput was about 18 h-1, low consumption of reagents and sample volume. The method was applied to the determination of Hg in sea water and river water. For the quality control of the analytical performance and the validation of the newly developed method, the analysis of two certified samples, TMDA 54.4 Fortified Lake, and LGC6187 River sediment was addressed. The results showed good agreement with the certified values.
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Electrical properties of polycrystalline gas sensors are analyzed by d.c. and a.c. measurements. d.c. electrical conductivity values compared with those obtained by admittance spectroscopy methods help to obtain a detailed 'on line' analysis of conductivity-modulated gas sensors. The electrical behaviour of grain boundaries is obtained and a new design of sensors can be achieved by enhancing the activity of surface states in the detecting operation. A Schottky barrier model is used to explain the grain boundary action under the presence of surrounding gases. The height of this barrier is a function of gas concentration due to the trapping of excess charge generated by gas adsorption at the interface. A comparison between this dependence, and a plot of the real and imaginary components of the admittance versus frequency at different gas concentrations, provides information on the different parameters that play a role in the conduction mechanisms. These methods have been applied to the design of a CO sensor based on tin oxide films for domestic purposes, the characteristics of which are presented.