Home

General-Use Nodal Network Solver (GUNNS)

GUNNS is a flow system modeling software package that combines nodal analysis and the hydraulic-electric analogy to simulate fluid, electrical, and thermal systems. Lyndon B. Johnson Space Center, Houston, Texas Crewed space vehicle training has always required highfidelity models of vehicle systems. Many of these systems, particularly of the “flow” variety, benefit from modeling the system as a whole, rather than relying only on the interactions between individual components. In general, system properties (temperatures, voltages, flow rates, etc.) are modeled both internal to and between physical components (valves, batteries, etc.). Lacking knowledge of the system atlarge, integration of flows between individual components is extremely difficult without incurring model instability and errors. The same analogous problem applies among fluid, thermal, and electrical systems. Nodal analysis is a method commonly used in industry to avoid this problem by representing these systems as a simultaneous system of equations.

Posted in: Briefs, TSP

Read More >>

Modularized SIR-to-NetCDF Conversion Command-Line Tool

NASA’s Jet Propulsion Laboratory, Pasadena, California This innovation reads in a proprietary formatted binary data format known as Scatterometer Image Reconstruction (SIR), and converts these data files to netCDF-classic format. This software is provided as a command-line tool for Linux/UNIX-based systems, and includes built-in regression testing and command line options. The software is configured to output the netCDF files using a metadata conformance to Attribute Convention for Dataset Discovery (ACDD) and Climate and Forecasting (CF) version 1.6. This software is initially tested and designed for SIR files created for datasets originating from QuikSCAT and SeaWinds on ADEOS-II.

Posted in: Briefs

Read More >>

Discovery Through Eigenbasis Modeling of Uninteresting Data

The system learns only what to ignore, reducing the possibility of missing the items of interest. NASA’s Jet Propulsion Laboratory, Pasadena, California When presented with a new data set, a common initial goal is to explore its contents in a discovery mode to find items of interest. However, each user who views the data set may have a different scientific goal in mind, and therefore a different desired prioritization of the items for examination. Further, as the users explore more of the data set, they accumulate concrete examples of what is or is not of interest. The goal of this work was to formalize this iterative approach to understanding large data sets, and instantiate it with methods capable of the necessary adaptation as the system iteratively acquires user feedback.

Posted in: Briefs, TSP

Read More >>

Obstacle Avoidance Methods

NASA’s Jet Propulsion Laboratory, Pasadena, California Obstacle avoidance is a difficult problem due to the non-convex state constraints. Therefore, the feasible state space needs to be convexified, or split, into convex regions at which point the search for an optimal solution among those convex regions is done. Methods for obstacle avoidance include two mixed integer linear programming (MILP) methods (obstacle related method and path-related method) and a state-constraint convexification method.

Posted in: Briefs, TSP

Read More >>

Bar Code Scanner to Supplement Property Inventory Process

There is no longer a need for any paper check-off sheets. Goddard Space Flight Center, Greenbelt, Maryland Within NASA Goddard, property inventories outside of the formal inventories had no automated method to perform quick checks of equipment location, especially during periods leading up to a formal inventory. One method that existed simply involved printing out an end-user’s equipment in a hard-copy form, and having each employee search for and annotate the results on the hard copy. These hard copies would then have to be returned to the property custodian. Information on the new whereabouts of equipment may or may not have been updated. This approach also relied on an honor system and the work styles of different individuals. Sometimes, multiple reminders needed to be sent to some employees to complete their inventory. In other cases, inventory was made more difficult because of the location of the equipment. A lot of property consists of test equipment in a lab environment. In this case, equipment is sometimes hard to access or grouped with numerous other pieces. These cases make it difficult to read off barcode numbers.

Posted in: Briefs, TSP

Read More >>

Semantic Language and Tools for Reporting Human Factors Incidents

Lyndon B. Johnson Space Center, Houston, Texas This human factors incident reporting tool for authoring and using human factors incident data combines semantic Web technologies with automated assistive technologies to aid users in finding relationships among incidents. The semantic indexing provided by the use of incident reporting language permits more sophisticated search of archives. During Phase I of this project, a semantic language for incident reporting in XML was defined, and a technology approach was designed for authoring and using incident reports represented in this language. In Phase II, this software was implemented and its effectiveness evaluated for the space human factors community at JSC.

Posted in: Briefs, TSP

Read More >>

Control Software for Integrated CW Radar Module

NASA’s Jet Propulsion Laboratory, Pasadena, California This software controls the behavior of a miniaturized microwave radar module. It controls the hardware, digitizes raw samples from the analog output of the module, and applies DSP (digital signal processing) algorithms to the data stream to reduce the bandwidth and data rate. It also implements an automatic calibration algorithm to adjust the I/Q (in-phase and quadrature) values in the cancellation path to remove a large unchanging signal. The software implements a variety of commands to control the behavior of the system, and provides for synchronization of multiple modules. It encodes the digital data in a format suitable for serial ports.

Posted in: Briefs, TSP

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.