Tech Briefs

Visualization of Terascale Datasets with Imposters

Goddard Space Flight Center, Greenbelt, Maryland The interactive visualization of large astrophysical datasets is a formidable challenge. Cosmological simulations performed on current terascale facilities typically generate datasets up to 100 gigabytes in size. In order to understand the complex three-dimensional structure within these simulations, interactive visualization with rapid rotation and zooming is required, but handling this much data is well beyond the capability of even current high-end graphics workstations. Rendering can be performed on a parallel computer, but the user typically is using such facilities remotely. Both the latency and bandwidth between the user’s workstation and the parallel machine preclude the possibility of interactive rendering.

Posted in: Briefs, TSP, Mathematical/Scientific Software

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Transforming DAVE-ML Models to Executable C/C++

Lyndon B. Johnson Space Center, Houston, Texas DMLtoC.xsl is an XSLT (Extensible Stylesheet Language Transformations) transform that converts a vehicle model described in DAVE-ML (an XML markup language) into a “C” language version of the same model. DAVE-ML is a markup language for describing aerodynamic vehicle models. A DAVE-ML representation of an aero-model is composed of elements and sub-elements that describe variables, variable initialization, mathematical expressions for calculating variable values, interpolation functions, and break-point values. The DMLtoC.xsl XSLT transform transforms a DAVE-ML description of an aerodynamic model into executable C code by transforming each of the model elements, as appropriate, into C/C++ variable declarations, variable initializers, assignment statements, function calls, and interpolation data structures while preserving the corresponding relationships between these elements.

Posted in: Briefs, TSP

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Context-Based Configuration Management System

Ames Research Center, Moffett Field, California This invention provides a visual and textual system, including a set of intuitive icons representing different activities, for indicating status of and/or change in a document or documents and/or in project operations, using the icons to indicate the presence of different classes of changes that have been introduced in the version displayed. Three distinct classes of status/changes are indicated, each class using one of several visually distinguishable icons to indicate the class and including additional textual information associated with the icon. Icons from different classes of activities have different shapes to allow for easier distinction between the classes.

Posted in: Briefs

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Mesh: Lightweight Grid Middleware Using Existing Secure Shell Infrastructure

This program has applications in homeland security and intrusion prevention. Ames Research Center, Moffett Field, California A software-based innovation called Mesh was developed that provides a single sign-on capability to the built-in public key authentication mechanism of Secure Shell (SSH) using system call interposition. Mesh is a secure, lightweight grid middleware. Each Mesh installation is dedicated to serving a particular virtual organization (VO), which is defined to be a dynamic collection of individuals, institutions, and resources. Mesh allows individuals in one VO to execute SSH remote commands on Mesh-accessible resources within other cooperating VOs using a single Mesh SSH private key generated at the local VO.

Posted in: Briefs

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Delay Tolerant Networking Contact Graph Routing MACHETE Model

NASA’s Jet Propulsion Laboratory, Pasadena, California This simulation environment of Contact Graph Routing that uses the QualNet network simulator leverages the previously developed space communication models. This software models the Contact Graph Routing (CGR) system proposed for future NASA missions and used in DINETl and DINET2 experiments. It runs inside the QualNet network simulator. This protocol model can assist NASA network designers who wish to use Delay Tolerant Networking protocols with Contact Graph Routing.

Posted in: Briefs, TSP

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JavaGenes Data Optimization

Ames Research Center, Moffett Field, California JavaGenes is a general-purpose software program that implements several different data optimization techniques. The program is intended for problems that have no gradient, comparing genetic algorithms with stochastic hill climbing and simulated annealing to generate optimal design solutions. JavaGenes can create many different data structures, and describe problems in a variety of ways.

Posted in: Briefs, TSP, Mathematical/Scientific Software, Simulation Software

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Low Er-Doped Yttrium Gallium Garnet (YGG) as Active Media for Solid-State Lasers at 1651 nm

This technology could serve applications in the bio-medical areas such as nerve stimulation and dentistry. Goddard Space Flight Center, Greenbelt, Maryland The typical approach for producing laser output at the 1651-nm wavelength is via nonlinear frequency conversion. Lasers based on nonlinear conversion are complex, and it is very difficult to provide stability over time and over a wide range of operating temperatures. The efficiency of such optical sources is also low. A much more promising approach is the use of active media that allows for the development of solid-state lasers (SSL) with spectral emission at 1651 nm. An important requirement for this active medium is the ability to support in-band pumping with a low quantum defect since this approach leads to significant improvement in efficiency of SSLs and excellent beam characteristics due to low thermal stress of the active media.

Posted in: Briefs, TSP, Lasers & Laser Systems

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