Information Technology & Software

Automated Generation of Reports of Mars Rover Operations

A document describes a system for the automated generation of reports of operations of a robotic exploratory vehicle (rover) on Mars. The automated report-generation system supplants a predominantly manual system, thereby making more information available in less time and reducing the probability of data-entry errors. The automated report-generation system has been incorporated into the Web Interface for Telescience, WITS, and utilizes information in the WITS database. (Described in several prior NASA Tech Briefs articles, the WITS is an Internet-based software system that enables geographically dispersed scientists and engineers to monitor and command a rover.)

Posted in: Briefs, TSP, Information Sciences, Internet, Data management, Documentation, Robotics, Spacecraft

Algorithms for Recognition of Objects in Color Stereo Images

Objects of known size, shape, and color can be recognized in real time.

Algorithms have been developed to enable a robotic vision system to recognize, in real time (at a rate between 0.5 and 2 frames per second), known objects lying on the ground. In the original intended application, the algorithms would be executed by off-the-shelf computer hardware aboard a robotic vehicle that would traverse military ordnance-testing ranges to search for unexploded bombs. A stereoscopic pair of color video cameras aboard the vehicle would acquire images of the terrain near the vehicle, and the algorithms would process the digitized images to recognize the bombs by their known size, shape, and color. The algorithms may also be adaptable to other, similar robotic-vision applications — for example, automated recognition of color traffic signs for alerting drivers in automobiles.

Posted in: Briefs, TSP, Information Sciences, Imaging and visualization, Robotics

A Metric for Visual Quality of Digital Video

This metric is based partly on human visual processing and is computationally efficient.

DVQ (which stands for "digital video quality") is a metric for evaluating the visual quality of digitized video images. Other video-quality metrics have been proposed, but it appears that each of them (1) may be based on mathematical models that are not related closely enough to the characteristics of human perception, in which case it may not measure visual quality accurately; or (2) may entail such large amounts of memory or computation that the contexts in which it can be applied are restricted. In contrast, DVQ was developed in an effort to incorporate mathematical models of human visual processing while maintaining computational efficiency so that accurate metrics can be computed in real time by use of modest computational resources.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Imaging and visualization

Cascade Error-Projection Learning in Neural Networks

This algorithm involves fewer iterations and can be implemented in simpler hardware.

Cascade error projection (CEP) is an improved learning algorithm for artificial neural networks. CEP is reliable and suitable for efficient implementation in very-large-scale integrated (VLSI) circuitry. In comparison with other neural-network-learning algorithms, CEP involves fewer iterations and is more tolerant of low resolution in the quantization of synaptic weights; thus, CEP learns relatively quickly and the circuitry needed to implement it is relatively simple.

Posted in: Briefs, TSP, Information Sciences, Integrated circuits, Neural networks

Expert System Controls and Monitors Thermal System

A symbolic controller recognizes malfunctions and takes corrective action.

The Thermal Expert System (TEXSYS) computer program exerts real-time control over a complicated thermal-regulatory system that includes evaporators, condensers, a pump, valves, and sensors. TEXSYS observes differences between actual and expected conditions and analyzes differences to determine whether a given condition signifies a malfunction in a component or at the system level. It then takes corrective action (e.g., it commands the opening or closing of a valve).

Posted in: Briefs, TSP, Information Sciences, Thermal management, Systems management

Partial Subtractive Dither for Lossy Data Compression

A new technique provides a compromise between benefits and costs of standard subtractive dither.

A technique of partial subtractive dither has been developed to improve the performance of any of a variety of near-lossless data-compression algorithms. The technique may be applicable to compression of scientific and medical image data.

Posted in: Briefs, TSP, Information Sciences, Mathematical models

Software for Preprocessing of Raw SAR Data

The SAR Processing System Raw Data Processor (SPS RDS) computer program is used in the Alaska SAR Facility (ASF) to scan and decode raw data that have been downlinked from the European Remote Sensing Satellite (ERS), the Japanese Earth Resources Satellite (JERS), and the RADARSAT (a Canadian Earth-observation satellite) and recorded on high-density digital tape or disk. ["SAR" means "synthetic-aperture radar."] In its scanning role, the program reads a recorded downlink bit stream, performs PRN decoding as needed, extracts auxiliary information to identify data-acquisition times, correlates this information with spacecraft state vector information to determine locations, and maps the locations to predefined fixed frames along an orbit track. These frames are stored in an archive as they become available, and are subsequently interrogated when requests for generation of image products are received. In its decoding role, this program converts a downlink bit stream that pertains to a requested frame into files that contain decoded engineering and SAR signal data that are compatible with the computers and programs used in further processing of SAR data into final image and image data products.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Data acquisition and handling, Remote sensing

Software for Locating Heterogeneous Data in Different Places

The Object Oriented Data Technology group at NASA's Jet Propulsion Laboratory is developing software for locating data — especially scientific data — stored in various formats on heterogeneous computer systems at different locations. The software is intended to exploit and extend advances in Internet software and in distributed object-oriented software to overcome the technological obstacles to integration of heterogeneous computing environments. The approach taken in this development involves refocusing effort on the development of metadata, which would be used to describe the available data resources and to support interoperability of computing systems. The software would manage a hierarchical conglomerate of data-set-resource definitions that would make it possible for application programs to locate the data that they require, without advance knowledge of which computer data systems and catalogs to search. This software would utilize the Extensible Markup Language (XML) and the Common Object Request Broker Architecture (CORBA) to support for interchange of data among heterogeneous sources. CORBA would enable over-the-wire exchange of XML-based profiles that would contain descriptions of data stored in remote computer systems.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Data acquisition and handling

Wavelet Analysis To Predict Limit Cycles

It is possible to predict the airspeed of onset of dangerous oscillations.

A method to predict the onset of a limit cycle for an aeroelastic testbed has been developed. The prediction is based on wavelet processing of measurement data that have been recorded under various flight conditions. The method has been considered for only a small testbed; however, the concepts may lead to techniques that could assist in prediction of the aeroelastic behaviors of aircraft during flight testing.

Posted in: Briefs, Information Sciences, Measurements, Flight tests

Program Automates Management of IBM VM Computer Systems

The VM Automated System computer program was developed to satisfy a need for efficient management of operations in a large client/server computer network that includes multiple mainframe computers and multiple local-area subnetworks. Functions performed by the program include the following:

Posted in: Briefs, Information Sciences, Computer software and hardware, Systems management, Automation

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