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MATTC Method for Efficient Prediction of Boundary Layer Transition

Langley Research Center, Hampton, Virginia The objective of the current innovation was to develop a simple but accurate method for predicting boundary layer transition that would include the growth characteristics of laminar boundary layer disturbances while requiring only the pressure distribution over an aerodynamic surface. Other existing methods either give only an estimate of the transition location [and only for surfaces where the TS (Tollmien–Schlichting) growth is the determiner of transition] with no disturbance growth characteristics, or require boundary layer information that must be extracted from a Navier-Stokes flow solver or obtained from a separate boundary layer solver.

Posted in: Briefs, Electronics & Computers, Software

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Google Earth Offline Cache Pre-loader v1 (GEOCP)

GEOCP gives disaster responders better and more reliable access to information in the field, while minimizing the amount of effort required before deployment. Ames Research Center, Moffett Field, California Google Earth is a geospatial browser produced by Google that allows interactive exploration of the world from data servers on the Internet. An integral part of Google Earth is a built-in “cache” that is stored locally on the user’s computer, and allows the user to later revisit previously viewed regions (even if the network link is disrupted or unavailable). The Google Earth cache is filled as the user interacts with Google Earth (i.e., flying and zooming the interface). The Google Earth Offline Cache Pre-loader (GEOCP) is a tool that allows users to specify a region to cache, and controls Google Earth to automatically and systematically fill the Google Earth cache. While connected to the Internet, the user specifies a latitude/longitude box, and a desired height above the ground. GEOCP then commands Google Earth to view the requested area in a lawnmower pattern, which has the side effect of bringing those areas into the Google Earth cache. When finished, the user is free to disconnect the network and continue to view the area.

Posted in: Briefs, Electronics & Computers, Software

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Robustness Analysis and Robust Design of Uncertain Systems

Langley Research Center, Hampton, Virginia A methodology was developed for the analysis and design of systems subject to parametric uncertainty in which design requirements are specified via hard inequality constraints. Hard constraints are those that must be satisfied for all parameter realizations within a given uncertainty model. Uncertainty models are given by norm-bounded perturbations from a nominal parameter value (i.e., hyperspheres) and by sets of independently bounded uncertain variables (i.e., hyperrectangles). These models, which are also quite practical, allow for a rigorous mathematical treatment within the proposed framework. Hardconstraint feasibility is determined by sizing the largest uncertainty set for which the design requirements are satisfied.

Posted in: Briefs, Electronics & Computers, Software

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XDB3 Extension for Equality and Relational Operators

Ames Research Center, Moffett Field, California While keyword full-text searches work well for textual data, they do not work well for numeric, date, or other more highly structured information. In particular, Netmark/XDB could retrieve any record where the author contained “Knight” in the text, but could not return only those records from Calendar Year 2010 that have “Knight” in their author section. Traditional relational databases allow for rich comparison “relational” operators; for example, one can express a query such as “return all rows where the signature date is on January 1, 2010.” Netmark/XDB, being primarily targeted at XML processing and retrieving XML-structured data, was designed for full-text querying to find keywords. Most other XML indexing and querying systems also are designed with the assumption that content (“CDATA”) is textual or binary data that can be queried against, but not with relational comparison operators like “greater than a value.”

Posted in: Briefs, Electronics & Computers, Software

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Simulator for a Self-Stabilizing Synchronization Protocol for Arbitrary Digraphs

Langley Research Center, Hampton, Virginia This work was conducted to create a means of simulating and visualizing the behavior of a self-stabilizing distributed clock synchronization protocol developed at LaRC (Langley Research Center). The protocol has many applications including projects that directly pertain to work being done at NASA. Time synchronization is a critical component of many projects, from computer networking and distributed systems, to autonomous flight. This easy-to-understand interface both displays accurate information concerning the protocol, and conveys its utility.

Posted in: Briefs, Electronics & Computers, Software

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Testing Encapsulation of Internet, DTN, and LTP Traffic over AOS Space Data Link Protocol

NASA’s Jet Propulsion Laboratory, Pasadena, California The CCSDS ENCAP Over AOS Over UDP software engine encapsulates live Internet Protocol (IP), DTN Bundle Protocol (BP), or Licklider Transport Protocol (LTP) traffic over a Consultative Committee for Space Data Systems (CCSDS)-compliant Encapsulation Ser vice (ENCAP) running over an Advanced Orbiting Systems (AOS) data link protocol UDP stream. Many space missions currently use the AOS protocol, and this software is an implementation of a standard mechanism to encapsulate Internet Protocol traffic (including interactive Web applications and streaming video) and DTN Bundle Protocol traffic (for large file transfers over high latency links) over ENCAP over AOS.

Posted in: Briefs, Electronics & Computers, Software

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Thinking About Switching CAD Platforms? Check out this report.

As CAD vendors adjust their licensing and software models and as your business deals with staffing and marketing changes it only makes sense to re-assess software requirements. With this report from Tech Clarity, you’ll have a fantastic guide to leverage on your journey.  Now you’ll have all the critical factors to consider when assessing your CAD platform. The in-depth examination covers topics such as: * Why change; * Setting organizational expectations; and * What’s import to leading CAD users.

Posted in: White Papers, Electronics & Computers, Manufacturing & Prototyping, Software

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