7,508 research outputs found
Evolution of AGN Space Densities and the FR Dichotomy
We focus on a comparison of the space densities of FRI and FRII extended
radio sources at different epochs, and find that FRI and FRII sources show
similar space density enhancements in various redshift ranges, possibly
implying a common evolution.Comment: IAU Symposium 267 Proceeding - 1 pag
Inventory of wetland habitat using remote sensing for the proposed Oahe irrigation unit in eastern South Dakota
An inventory of wetlands for the area included in the proposed Oahe irrigation project was conducted to provide supplemental data for the wildlife mitigation plan. Interpretation techniques for inventoring small wetlands in the low relief terrain of the Lake Dakota Plain were documented and data summaries included. The data were stored and tabulated in a computerized spatial data analysis system
Application of remote sensing technology to land evaluation, planning utilization of land resources, and assessment of westland habitat in eastern South Dakota, parts 1 and 2
The author has identified the following significant results. LANDSAT fulfilled the requirements for general soils and land use information. RB-57 imagery was required to provide the information and detail needed for mapping soils for land evaluation. Soils maps for land evaluation were provided on clear mylar at the scale of the county highway map to aid users in locating mapping units. Resulting mapped data were computer processed to provided a series of interpretive maps (land value, limitations to development, etc.) and area summaries for the users
A short survey on nonlinear models of the classic Costas loop: rigorous derivation and limitations of the classic analysis
Rigorous nonlinear analysis of the physical model of Costas loop --- a
classic phase-locked loop (PLL) based circuit for carrier recovery, is a
challenging task. Thus for its analysis, simplified mathematical models and
numerical simulation are widely used. In this work a short survey on nonlinear
models of the BPSK Costas loop, used for pre-design and post-design analysis,
is presented. Their rigorous derivation and limitations of classic analysis are
discussed. It is shown that the use of simplified mathematical models, and the
application of non rigorous methods of analysis (e.g., simulation and
linearization) may lead to wrong conclusions concerning the performance of the
Costas loop physical model.Comment: Accepted to American Control Conference (ACC) 2015 (Chicago, USA
Cosmic Crystallography with a Pullback
We present a modified version of the cosmic crystallography method,
especially useful for testing closed models of negative spatial curvature. The
images of clusters of galaxies in simulated catalogs are ``pulled back'' to the
fundamental domain before the set of distances is calculated.Comment: 9 pages, 2 figure
Some Fundamental Properties of a Multivariate von Mises Distribution
In application areas like bioinformatics multivariate distributions on angles
are encountered which show significant clustering. One approach to statistical
modelling of such situations is to use mixtures of unimodal distributions. In
the literature (Mardia et al., 2011), the multivariate von Mises distribution,
also known as the multivariate sine distribution, has been suggested for
components of such models, but work in the area has been hampered by the fact
that no good criteria for the von Mises distribution to be unimodal were
available. In this article we study the question about when a multivariate von
Mises distribution is unimodal. We give sufficient criteria for this to be the
case and show examples of distributions with multiple modes when these criteria
are violated. In addition, we propose a method to generate samples from the von
Mises distribution in the case of high concentration.Comment: fixed a typo in the article title, minor fixes throughou
The CoNFIG Catalogue - II. Comparison of Space Densities in the FR Dichotomy
This paper focuses on a comparison of the space densities of FRI and FRII
sources at different epochs, with a particular focus on FRI sources. First, we
present the concluding steps in constructing the Combined NVSS-FIRST Galaxy
catalogue (CoNFIG), including new VLA observations, optical identifications and
redshift estimates. The final catalogue consists of 859 sources over 4 samples
(CoNFIG-1, 2, 3 and 4 with flux density limits of S_1.4GHz = 1.3, 0.8, 0.2 and
0.05 Jy respectively). It is 95.7% complete in radio morphology classification
and 74.3% of the sources have redshift data. Combining CoNFIG with
complementary samples, the distribution and evolution of FRI and FRII sources
are investigated. We find that FRI sources undergo mild evolution and that, at
the same radio luminosity, FRI and FRII sources show similar space density
enhancements in various redshift ranges, possibly implying a common evolution.Comment: 15 pages, 15 figures, 6 tables + appendix (80 pages). accepted in
M.N.R.A.
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