10,057 research outputs found
Space Station Displays and Controls Technology Evolution
Viewgraphs on space station displays and controls technology evolution are presented. Topics covered include: a historical perspective; major development objectives; current development activities; key technology areas; and technology evolution issues
Morita theory and singularity categories
We propose an analogue of the bounded derived category for an augmented ring
spectrum, defined in terms of a notion of Noether normalization. In many cases
we show this category is independent of the chosen normalization. Based on
this, we define the singularity and cosingularity categories measuring the
failure of regularity and coregularity and prove they are Koszul dual in the
style of the BGG correspondence. Examples of interest include Koszul algebras
and Ginzburg DG-algebras, for finite groups (or for compact Lie
groups with orientable adjoint representation), cochains in rational homotopy
theory and various examples from chromatic homotopy theory.Comment: Final version, accepted for publication in Advances in Mathematics,
49 page
Current Accounts and Exchange Rates: A New Look at the Evidence
This paper 'goes back to basics' in empirical analysis of the J-Curve. First, we document strong violations in the distributional assumptions that underlie nearly all previous work on this issue. Second, we employ distribution-free, non-parametric statistical tests to characterize the data and summarize the key relationships between real exchange rates, the current account, and real GDP. We find some (weak) evidence of a J-Curve in the data. Interestingly, however, we document that this evidence is not consistent with the standard theoretical explanation of the J-Curve. Consequently, our empirical results pose a strong challenge for international economic theory.
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Determining Utility System Value of Demand Flexibility From Grid-interactive Efficient Buildings
This report focuses on ways current methods and practices that establish the value to electric utility systems of distributed energy resource (DER) investments can be enhanced to determine the value of demand flexibility in grid-interactive efficient buildings that can provide grid services. The report introduces key valuation concepts that are applicable to demand flexibility that these buildings can provide and links to other documents that describe these concepts and their implementation in more detail.The scope of this report is limited to the valuation of economic benefits to the utility system. These are the foundational values on which other benefits (and costs) can be built. Establishing the economic value to the grid of demand flexibility provides the information needed to design programs, market rules, and rates that align the economic interest of utility customers with building owners and occupants. By nature, DERs directly impact customers and provide societal benefits external to the utility system. Jurisdictions can use utility system benefits and costs as the foundation of their economic analysis but align their primary cost-effectiveness metric with all applicable policy objectives, which may include customer and societal (non-utility system) impacts.This report suggests enhancements to current methods and practices that state and local policymakers, public utility commissions, state energy offices, utilities, state utility consumer representatives, and other stakeholders might support. These enhancements can improve the consistency and robustness of economic valuation of demand flexibility for grid services. The report concludes with a discussion of considerations for prioritizing implementation of these improvements
Luminosities and mass-loss rates of Local Group AGB stars and Red Supergiants
We aim to investigate mass loss and luminosity in a large sample of evolved
stars in several Local Group galaxies with a variety of metalliticies and
star-formation histories: the Small and Large Magellanic Cloud, and the Fornax,
Carina, and Sculptor dwarf spheroidal galaxies. Dust radiative transfer models
are presented for 225 carbon stars and 171 oxygen-rich evolved stars for which
spectra from the Infrared Spectrograph on Spitzer are available. The spectra
are complemented with available optical and infrared photometry to construct
spectral energy distributions. A minimization procedure was used to determine
luminosity and mass-loss rate (MLR). Pulsation periods were derived for a large
fraction of the sample based on a re-analysis of existing data. New deep K-band
photometry from the VMC survey and multi-epoch data from IRAC and
AllWISE/NEOWISE have allowed us to derive pulsation periods longer than 1000
days for some of the most heavily obscured and reddened objects. We derive
(dust) MLRs and luminosities for the entire sample. The estimated MLRs can
differ significantly from estimates for the same objects in the literature due
to differences in adopted optical constants (up to factors of several) and
details in the radiative transfer modelling. Updated parameters for the
super-AGB candidate MSX SMC 055 (IRAS 00483-7347) are presented. Its current
mass is estimated to be 8.5 +- 1.6 \msol, suggesting an initial mass well above
8~\msol. Using synthetic photometry, we present and discuss colour-colour and
colour-magnitude diagrams which can be expected from the James Webb Space
Telescope.Comment: A&A accepted. The full version (100 pages, 12 MB) with complete
tables and all figures of the appendices is available at
http://homepage.oma.be/marting/articlesgroen.htm
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