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XML DTD and Schemas for HDF-EOS

An Extensible Markup Language (XML) document type definition (DTD) standard for the structure and contents of HDF-EOS files and their contents, and an equivalent standard in the form of schemas, have been developed. (“HDF-EOS” and variants thereof are defined in the first two of four related articles immediately preceding this one.) More specifically, this standard describes the structure and contents of a single HDF-EOS 5 file based on the HDF-EOS model as published in Volumes 1 and 2 of the HDF-EOS Library Users Guide. The DTD and schemas are easy-to-use representations of a complex file format, enabling display of data in multiple ways.

Posted in: Briefs, TSP, Software

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Converting From XML to HDF-EOS

A computer program recreates an HDF-EOS file from an Extensible Markup Language (XML) representation of the contents of that file. (“HDF-EOS” and variants thereof are defined in the first of five related articles that immediately precede this article.) This program is one of two programs written to enable testing of the schemas described in the immediately preceding article to determine whether the schemas capture all details of HDF-EOS files. (The other program converts an HDF-EOS file into an XML file.) This program uses a General Purpose Language (GPL) parser called “expat” to parse XML and control extraction of data from an input XML file.

Posted in: Briefs, TSP, Software

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Simulating Attitudes and Trajectories of Multiple Spacecraft

A computer program called “42” simulates the attitudes and trajectories of multiple spacecraft flying in formation anywhere in the Solar System. The rotational dynamics are represented by high-fidelity models of spacecraft, each comprising as many as three connected rigid bodies and containing as many as four flywheel mechanisms for storing angular momentum for controlling attitude. The translational dynamics are represented partly by Encke’s method of orbit perturbation, which enables the use of a reference trajectory shared by multiple spacecraft and, in so doing, enables separation of gigameter-scale trajectory features from nanometer-scale formation adjustments to preserve the numerical accuracy needed for simulating precise multi-spacecraft formations.

Posted in: Briefs, TSP, Software

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Alternative Approaches to Basis Weight Reduction in Paper

A company seeks technology to replace wood fiber in paper with a bulk filler material having less mass. The company seeks to make small, micron-scale, low-density particles. The filler material would have no negative impact on today’s lightweight paper specifications, including bulk (caliper), strength, stiffness, printability (ex. formation, porosity, showthrough), or brightness. Respond to this TechNeed at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: NASA Tech Needs

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Specialized Color Function for Display of Signed Data

This Mathematica script defines a color function to be used with Mathematica’s plotting modules for differentiating data attaining both positive and negative values. Positive values are shown as shades of blue, and negative values are shown in red. The intensity of the color reflects the absolute value of the data value.

Posted in: Briefs, Information Sciences

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Delivering Alert Messages to Members of a Work Force

Global Alert Resolution Network (GARNET) is a software system for delivering emergency alerts as well as less-urgent messages to members of the Goddard Space Flight Center work force via an intranet or the Internet, and can be adapted to similar use in other large organizations. Messages can be presented in visible and audible forms on such diverse terminals as desktop computers, portable alphanumeric pagers, telephones, fire alarms, and closed-circuit television. GARNET includes client components running on workers’ desktop computers, and server components running on redundant computers behind firewalls.

Posted in: Briefs, TSP, Software

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Oxide Fiber Cathode Materials for Rechargeable Lithium Cells

LiCoO2 and LiNiO2 fibers have been investigated as alternatives to LiCoO2 and LiNiO2 powders used as lithium-intercalation compounds in cathodes of rechargeable lithium-ion electrochemical cells. In making such a cathode, LiCoO2 or LiNiO2 powder is mixed with a binder [e.g., poly(vinylidene fluoride)] and an electrically conductive additive (usually carbon) and the mixture is pressed to form a disk. The binder and conductive additive contribute weight and volume, reducing the specific energy and energy density, respectively.

Posted in: Briefs, Materials

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