496 research outputs found

    Impacts of different SNLS3 light-curve fitters on cosmological consequences of interacting dark energy models

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    We explore the cosmological consequences of interacting dark energy (IDE) models using the SNLS3 supernova samples. In particular, we focus on the impacts of different SNLS3 light-curve fitters (LCF) (corresponding to "SALT2", "SiFTO", and "Combined" sample). Firstly, making use of the three SNLS3 data sets, as well as the Planck distance priors data and the galaxy clustering data, we constrain the parameter spaces of three IDE models. Then, we study the cosmic evolutions of Hubble parameter H(z)H(z), deceleration diagram q(z)q(z), statefinder hierarchy S3(1)(z)S^{(1)}_3(z) and S4(1)(z)S^{(1)}_4(z), and check whether or not these dark energy diagnosis can distinguish the differences among the results of different SNLS3 LCF. At last, we perform high redshift cosmic age test using three old high redshift objects (OHRO), and explore the fate of the Universe. We find that, the impacts of different SNLS3 LCF are rather small, and can not be distinguished by using H(z)H(z), q(z)q(z), S3(1)(z)S^{(1)}_3(z), S4(1)(z)S^{(1)}_4(z), and the age data of OHRO. In addition, we infer, from the current observations, how far we are from a cosmic doomsday in the worst case, and find that the "Combined" sample always gives the largest 2σ\sigma lower limit of the time interval between "big rip" and today, while the results given by the "SALT2" and the "SiFTO" sample are close to each other. These conclusions are insensitive to a specific form of dark sector interaction. Our method can be used to distinguish the differences among various cosmological observations.Comment: 12 pages, 7 figures, 2 tables, accepted for publication in Astronomy and Astrophysic

    A Study of Renewable Portfolio Standards and Renewable Energy Certificate Prices in Five Northeastern States

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    A number of US states have passed renewable portfolio standard, a mandate that ensures a certain amount of energy to be generated by renewable sources, to offset carbon emission or create local jobs. While states\u27 renewable portfolio standards have similar features, their designs vary substantially. In this paper, I investigate the design features and renewable energy certificate prices in five northeastern states that are trading in two trading systems to see how renewable portfolio standards are working in those states. The regression on bidding and asking price differences reveals considerable differences among states in Class I renewable energy certificate prices and differences between bid and asking price. This leads us to question the effectiveness of these portfolio standards

    A Study of Renewable Portfolio Standards and Renewable Energy Certificate Prices in Five Northeastern States

    Get PDF
    A number of US states have passed renewable portfolio standard, a mandate that ensures a certain amount of energy to be generated by renewable sources, to offset carbon emission or create local jobs. While states\u27 renewable portfolio standards have similar features, their designs vary substantially. In this paper, I investigate the design features and renewable energy certificate prices in five northeastern states that are trading in two trading systems to see how renewable portfolio standards are working in those states. The regression on bidding and asking price differences reveals considerable differences among states in Class I renewable energy certificate prices and differences between bid and asking price. This leads us to question the effectiveness of these portfolio standards

    A quasi-current representation for information needs inspired by Two-State Vector Formalism

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    Recently, a number of quantum theory (QT)-based information retrieval (IR) models have been proposed for modeling session search task that users issue queries continuously in order to describe their evolving information needs (IN). However, the standard formalism of QT cannot provide a complete description for users’ current IN in a sense that it does not take the ‘future’ information into consideration. Therefore, to seek a more proper and complete representation for users’ IN, we construct a representation of quasi-current IN inspired by an emerging Two-State Vector Formalism (TSVF). With the enlightenment of the completeness of TSVF, a “two-state vector” derived from the ‘future’ (the current query) and the ‘history’ (the previous query) is employed to describe users’ quasi-current IN in a more complete way. Extensive experiments are conducted on the session tracks of TREC 2013 & 2014, and show that our model outperforms a series of compared IR models
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