15,922 research outputs found

    Loran-C plotting program for plotting lines of position on standard charts

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    A set of programs used to plot Loran C lines of position on any common map or standard aviation sectional chart are given. The Loran C plotting program JRPLOT FORTRAN uses a standard Calcomp compatible plotting subroutine package for the Hewlett-Packard 7203A graphic plotter. The programs are designed to be run on an IBM System 370 computer. A simple add subtract method is used to calculate the lines of position. A description of how to use the program and some methods of operation are given

    Web of Failure: The Relationship Between Foster Care and Homelessness

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    The purpose of this project is to examine the connection between foster care and homelessness and to determine whether or not there is an over-representation of people with a foster care history in the homeless population. In order to examine this issue, the project used four sources of information: (1) existing research on the connection between foster care and homelessness; (2) data collected from organizations which serve homeless people and which gather information on their clients' foster care history; (3) data obtained directly from a sample of homeless people; and (4) case studies of people who are or were homeless and who have a foster care history

    An algorithm for moment-matching scenario generation with application to financial portfolio optimization

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    We present an algorithm for moment-matching scenario generation. This method produces scenarios and corresponding probability weights that match exactly the given mean, the covariance matrix, the average of the marginal skewness and the average of the marginal kurtosis of each individual component of a random vector. Optimisation is not employed in the scenario generation process and thus the method is computationally more advantageous than previous approaches. The algorithm is used for generating scenarios in a mean-CVaR portfolio optimisation model. For the chosen optimisation example, it is shown that desirable properties for a scenario generator are satisfied, including in-sample and out-of-sample stability. It is also shown that optimal solutions vary only marginally with increasing number of scenarios in this example; thus, good solutions can apparently be obtained with a relatively small number of scenarios. The proposed method can be used either on its own as a computationally inexpensive scenario generator or as a starting point for non-convex optimisation based scenario generators which aim to match all the third and the fourth order marginal moments (rather than average marginal moments)

    A simple renormalization group approximation of the groundstate properties of interacting bosonic systems

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    We present a new, simple renormalization group method of investigating groundstate properties of interacting bosonic systems. Our method reduces the number of particles in a system, which makes numerical calculations possible for large systems. It is conceptually simple and easy to implement, and allows to investigate the properties unavailable through mean field approximations, such as one- and two-particle reduced density matrices of the groundstate. As an example, we model a weakly interacting 1D Bose gas in a harmonic trap. Compared to the mean-field Gross-Pitaevskii approximation, our method provides a more accurate description of the groundstate one-particle density matrix. We have also obtained the Hall-Post lower bounds for the groundstate energy of the gas. All results have been obtained by the straightforward numerical diagonalization of the Hamiltonian matrix.Comment: RevTex 4, 12 figures (revised and updated); to appear in Physical Review
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