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Frame Synchronization Without Attached Sync Markers

A means has been developed to detect the positions of code words directly. NASA’s Jet Propulsion Laboratory, Pasadena, California In communications systems, there must be a method to identify the beginning of a message at the receiving end, to know when the data stream of a specified structure begins. This is conventionally done by inserting attached sync markers (ASMs) between codewords, and looking for these ASMs in the transmitted data. Instead, a means has been developed to detect the positions of codewords directly, using the decoder to partially process a decoder attempt at each candidate synchronization position. A short decoding operation can successfully synchronize codewords in about two seconds in software.

Posted in: Briefs, TSP, Electronics & Computers

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Scalable ParaView for Extreme Scale Visualization

Goddard Space Flight Center, Greenbelt, Maryland Work has been focused on identifying bottlenecks in visualization pipelines that make the visualization and analysis of large datasets in real time difficult to attain. The innovators leveraged ParaView, an open-source visualization application and framework, to provide custom solutions for users of NASA’s high-performance computing (HPC) resources instead of conducting high-risk research. Issues regarding different types of data (grid-based and particle-based) have been addressed, and overheads dealing with challenging multivariate data from global 3D full particle simulations were addressed by working closely with ParaView users.

Posted in: Briefs, TSP, Electronics & Computers, Simulation Software

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Explicit Filtering Leading to Grid-Spacing-Independent and Discretization-Order-Independent Large Eddy Simulation Solutions

Two-phase volumetrically dilute flow with evaporation is addressed. NASA’s Jet Propulsion Laboratory, Pasadena, California Numerical simulations for turbulent flows using the most promising methodology, Large Eddy Simulation (LES), are grid-spacing and discretization-order dependent. This means that the solution is not trustworthy and cannot be compared with experiments to determine the validity of the mathematical model.

Posted in: Briefs, Electronics & Computers, Simulation Software

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Explicit Filtering Leading to Grid-Independent and Discretization-Order-Independent Large Eddy Simulation

The re-formulation involves explicit filtering of the conservation equations. NASA’s Jet Propulsion Laboratory, Pasadena, California To validate simulations, one must trust that they are independent of the numerical aspects. A very promising, relatively new methodology for simulating turbulent flows, called Large Eddy Simulation (LES), has some issues in this respect. The issues stem from the aspect that modeling and numerics are totally intertwined, resulting in the fact that the results are grid-dependent and discretization-order-dependent. These issues were described in the preceding article. These issues prevent LES validation with experiments since one can always make adjustments to agree with data, which is not validation.

Posted in: Briefs, Electronics & Computers, Simulation Software

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Mars Science Laboratory Second-Chance Flight Software

NASA’s Jet Propulsion Laboratory, Pasadena, California Mars lander spacecraft, beginning with Mars Pathfinder (MPF), have been designed to tolerate flight computer resets during the entry, descent, and landing (EDL) phase despite having only a single flight computer. This capability was enabled by a predictable, non-dynamic EDL architecture. The Mars Science Laboratory (MSL) spacecraft has a highly dynamic EDL architecture as well as dual flight computers, adding more complexity to EDL flight software fault tolerance.

Posted in: Briefs, Aviation, Electronics & Computers

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Multi-User Investigation Organizer

Ames Research Center, Moffett Field, California InvestigationOrganizer (IO) is a Web-based information system that integrates the generic functionality of a database, a document repository, a semantic hyper-media browser, and a rule-based inference system with specialized modeling and visualization functionality to support mishap investigations. The semantic hypermedia component includes a customizable ontology that specifies various types of items (people, places, events, causes, systems, and associated information products) relevant to mishap investigations. The ontology also describes important properties of each item type, and details the potential relationships among items.

Posted in: Briefs, Electronics & Computers

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Unit Conversion Macro for TecPlot Solutions for CFD

Lyndon B. Johnson Space Center, Houston, Texas The invention is a TecPlot macro, which is a computer program in the TecPlot programming language that processes CFD (computational fluid dynamics) solutions in TecPlot format. The TecPlot data is in SI units (International System of Units) [same as CFD solutions]. This invention converts the SI units into U.S. customary units.

Posted in: Briefs, Electronics & Computers, Mathematical/Scientific Software

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