Small Scale Perturbations in a General MDM Cosmology

For a universe with massive neutrinos, cold dark matter, and baryons, we solve the linear perturbation equations analytically in the small-scale limit and find agreement with numerical codes at the 1-2% level. The inclusion of baryons, a cosmological constant, or spatial curvature reduces the small-scale power and tightens limits on the neutrino density from observations of high redshift objects. Using the asymptotic solution, we investigate neutrino infall into potential wells and show that it can be described on all scales by a growth function that depends on time, wavenumber, and cosmological parameters. The growth function may be used to scale the present-day transfer functions back in redshift. This allows us to construct the time-dependent transfer function for each species from a single master function that is independent of time, cosmological constant, and curvature.Comment: Submitted to ApJ; 13 pages, aastex, 4 figures included; also available at http://www.sns.ias.edu/~wh

The Structure of Structure Formation Theories

We study the general structure of models for structure formation, with applications to the reverse engineering of the model from observations. Through a careful accounting of the degrees of freedom in covariant gravitational instability theory, we show that the evolution of structure is completely specified by the stress history of the dark sector. The study of smooth, entropic, sonic, scalar anisotropic, vector anisotropic, and tensor anisotropic stresses reveals the origin, robustness, and uniqueness of specific model phenomenology. We construct useful and illustrative analytic solutions that cover cases with multiple species of differing equations of state relevant to the current generation of models, especially those with effectively smooth components. We present a simple case study of models with phenomenologies similar to that of a LambdaCDM model to highlight reverse-engineering issues. A critical-density universe dominated by a single type of dark matter with the appropriate stress history can mimic a LambdaCDM model exactly.Comment: 31 pages, 18 figures, RevTeX, submitted to Phys. Rev.

Reusing terminology for requirements specifications from WordNet

In order to make requirements comprehensible to humans and as unambiguous as possible, a glossary and/or domain model is needed for defining the terminology used. Unless these are available from related projects, however, they are hard to create. Therefore, we propose to reuse terminology and its definition for requirements specifications from the semantic lexicon WordNet. For making this useful, however, we had to deal with the issue of disambiguation of the general terminology there for a given domain of a requirements specification.

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Title Reuse-Oriented Modelling and Transformation Language Definition Subtitle

Oriented_Modelling_and_Transformation_Language_Definition.pdf Version 1.0 Status Final Distribution Public The information in this document is provided as is and no guarantee or warranty is given that the information is fit for any particular purpose. The user thereof uses the information at its sole risk and liability

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