976 resultados para Artigo zero
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The authors present the impact of asymmetric filtering of strong (e.g. 35 GHz) optical filters on the performance of 42.7 Gb/s 67% (carrier suppressed return to zero)-differential phase shift keying systems. The performance is examined (in an amplified spontaneous emission (ASE) noise-limited regime and in the presence of chromatic dispersion) when offsetting the filter at the receiver by substantial amounts via balanced, constructive and destructive single-ended detections. It is found that with a slight offset (vestigial side band) or an offset of almost half of the modulation frequency (single-side band), there is a significant improvement in the calculated 'Q'. © The Institution of Engineering and Technology 2013.
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AMS Subject Classification 2010: 11M26, 33C45, 42A38.
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2000 Mathematics Subject Classification: Primary 13A99; Secondary 13A15, 13B02, 13E05.
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2000 Mathematics Subject Classification: 14B05, 32S25.
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ACM Computing Classification System (1998): G.1.2.
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A novel multichannel carrier-suppressed return-to-zero (CSRZ) to non-return-to-zero (NRZ) format conversion scheme based on a single custom-designed fiber Bragg grating (FBG) with comb spectra is proposed. The spectral response of each channel is designed according to the algebraic difference between the CSRZ and NRZ spectra outlines. The tailored group delays are introduced to minimize the maximum refractive index modulation. Numerical results show that four-channel 200-GHz-spaced CSRZ signals at 40 Gbits/s can be converted into NRZ signals with high Q-factor and wide-range robustness. It is shown that our proposed FBG is robust to deviations of bandwidth and central wavelength detuning. Another important merit of this scheme is that the pattern effects are efficiently reduced owing to the well-designed spectra response.
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In the U.S., construction accidents remain a significant economic and social problem. Despite recent improvement, the Construction industry, generally, has lagged behind other industries in implementing safety as a total management process for achieving zero accidents and developing a high-performance safety culture. One aspect of this total approach to safety that has frustrated the construction industry the most has been “measurement”, which involves identifying and quantifying the factors that critically influence safe work behaviors. The basic problem attributed is the difficulty in assessing what to measure and how to measure it—particularly the intangible aspects of safety. Without measurement, the notion of continuous improvement is hard to follow. This research was undertaken to develop a strategic framework for the measurement and continuous improvement of total safety in order to achieve and sustain the goal of zero accidents, while improving the quality, productivity and the competitiveness of the construction industry as it moves forward. The research based itself on an integral model of total safety that allowed decomposition of safety into interior and exterior characteristics using a multiattribute analysis technique. Statistical relationships between total safety dimensions and safety performance (measured by safe work behavior) were revealed through a series of latent variables (factors) that describe the total safety environment of a construction organization. A structural equation model (SEM) was estimated for the latent variables to quantify relationships among them and between these total safety determinants and safety performance of a construction organization. The developed SEM constituted a strategic framework for identifying, measuring, and continuously improving safety as a total concern for achieving and sustaining the goal of zero accidents.
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This study is an attempt at achieving Net Zero Energy Building (NZEB) using a solar Organic Rankine Cycle (ORC) based on exergetic and economic measures. The working fluid, working conditions of the cycle, cycle configuration, and solar collector type are considered the optimization parameters for the solar ORC system. In the first section, a procedure is developed to compare ORC working fluids based on their molecular components, temperature-entropy diagram and fluid effects on the thermal efficiency, net power generated, vapor expansion ratio, and exergy efficiency of the Rankine cycle. Fluids with the best cycle performance are recognized in two different temperature levels within two different categories of fluids: refrigerants and non-refrigerants. Important factors that could lead to irreversibility reduction of the solar ORC are also investigated in this study. In the next section, the system requirements needed to maintain the electricity demand of a geothermal air-conditioned commercial building located in Pensacola of Florida is considered as the criteria to select the optimal components and optimal working condition of the system. The solar collector loop, building, and geothermal air conditioning system are modeled using TRNSYS. Available electricity bills of the building and the 3-week monitoring data on the performance of the geothermal system are employed to calibrate the simulation. The simulation is repeated for Miami and Houston in order to evaluate the effect of the different solar radiations on the system requirements. The final section discusses the exergoeconomic analysis of the ORC system with the optimum performance. Exergoeconomics rests on the philosophy that exergy is the only rational basis for assigning monetary costs to a system’s interactions with its surroundings and to the sources of thermodynamic inefficiencies within it. Exergoeconomic analysis of the optimal ORC system shows that the ratio Rex of the annual exergy loss to the capital cost can be considered a key parameter in optimizing a solar ORC system from the thermodynamic and economic point of view. It also shows that there is a systematic correlation between the exergy loss and capital cost for the investigated solar ORC system.
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With this thesis, we investigate papers produced by candidates to the vestibular 2010 from UFRN related to the (non) taking on of different points of view in the textual zone of the argumentation and counter-argumentation. The candidates had to produce an opinion article about the polemic theme of the security cameras. The corpus of this research contents 100 papers produced by the candidates to the vestibular 2010 from different areas (humans I, humans II, technological I, technological II and biomedical). To this study, we are based on theoretical perspectives from authors of different theories and linguistic fields that dialog among them. In this direction, we follow Bakhtin (1995), Rabatel (2008 a, 2008 b), Guentchéva (1994, 1996, 2011) and Rodrigues, Passeggi e Silva Neto (2010), among others, that are concerned to dialogism, enunciative theories, discuss analyzes, and linguistic of the text. This group of linguistic approach is linked to the Textual Analyze of the Discuss (ADAM, 2011), that conducts analyze of the data of this research. Related to the methodology, we follow the qualitative analyze in an interpretative way. We investigate how the candidate, as a writer, takes on information inserted in his/her paper. With this in mind, this research tries to answer the following questions: (1) How the candidate organizes his/her discuss in respect to the enunciative responsibility? (2) Which linguistic marks conduct to identify the different voices in the texts? (3) How the textual plan is presented in the opinion article? (4) In which part of the textual plan is possible to identify the enunciative responsibility? In this sense, the aims of this study are identify, describe, analyze and interpret the different voices presented in the text and the way the candidate takes on (or not) the different points of view presented in the papers during argumentation and counterargumentation movement. In general, the results reveal that the presence of linguistic marks (connectors, people marks, among others) design the grade of enunciative responsibility of the writer, stimulating his/her involving and taking on enunciative responsibility.
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The authors wish to acknowledge the valuable comments and suggestions made by members of the Committee of Fisheries of the European Parliament. The authors also thank the financial support of the European Parliament (IP/B/PECH/IC/2014–084) and the assistance of Ojama Priit and Marcus Brewer. SV acknowledges the financial support from the Spanish Agency for International Development Cooperation (AECID) (Grant no 11-CAP2–1406) and the Galician Government (Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia) (Grant no R2014/023). MC acknowledges the financial support from the European Commission through the Marie Curie Career Integration Grant Fellowships – PCIG10-GA-2011–303534 - to the BIOWEB project. CP and GP acknowledge the financial support of Caixa Geral de Depósitos (Portugal) and the University of Aveiro. CP would also like to acknowledge FCT/MEC national funds and FEDER co-funding, within the PT2020 partnership Agreement and Compete 2020, for the financial support to CESAM (Grant no UID/AMB/50017/2013). JMDR and JGC thanks the financial support from the European Commission (MINOW H2020-SFS-2014–2, No 634495) and Xunta de Galicia (GRC 2015/014 and ECOBAS). MA acknowledges financial aid of Xunta de Galicia through Project GPC 2013–045. URS and CP acknowledge the Too Big to Ignore Partnership supported by the Social Sciences and Humanities Research Council of Canada (SSHRC).
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INTRODUCTION Zero-G parabolic flight reproduces the weightlessness of space for short periods of time. However motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors. METHODS Airbus Zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20s 0g sandwiched by 20s hypergravity of 1.5-1.8g. The survey covered n=246 person-flights (193 Males 53 Females), aged (M+/-SD) 36.0+/-11.3 years. An anonymous questionnaire included motion sickness rating (1=OK to 6=Vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), anti-motion sickness medication, prior Zero-G experience, anxiety level, and other characteristics. RESULTS Participants had lower MSSQ percentile scores 27.4+/-28.0 than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior Zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender nor anxiety. Sickness ratings in fliers pre-treated with scopolamine (1.81+/-1.58) were lower than for non-medicated fliers (2.93+/-2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, MSSQ, could not account for this. CONCLUSION Motion sickness affected one third of Zero-G fliers, despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior Zero-G flight experience (habituation) and anti-motion sickness medication.
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In Marxist frameworks “distributive justice” depends on extracting value through a centralized state. Many new social movements—peer to peer economy, maker activism, community agriculture, queer ecology, etc.—take the opposite approach, keeping value in its unalienated form and allowing it to freely circulate from the bottom up. Unlike Marxism, there is no general theory for bottom-up, unalienated value circulation. This paper examines the concept of “generative justice” through an historical contrast between Marx’s writings and the indigenous cultures that he drew upon. Marx erroneously concluded that while indigenous cultures had unalienated forms of production, only centralized value extraction could allow the productivity needed for a high quality of life. To the contrary, indigenous cultures now provide a robust model for the “gift economy” that underpins open source technological production, agroecology, and restorative approaches to civil rights. Expanding Marx’s concept of unalienated labor value to include unalienated ecological (nonhuman) value, as well as the domain of freedom in speech, sexual orientation, spirituality and other forms of “expressive” value, we arrive at an historically informed perspective for generative justice.