Briefs : Information Technology
Cascade Error-Projection Learning in Neural Networks

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...

Briefs : Information Technology
Expert System Controls and Monitors Thermal System

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...

Briefs : Physical Sciences
Biomorphic Gliders

Biomorphic gliders are small robotic microflyers proposed for use in scientific exploration of planetary atmospheres and terrains that capture some key features of insect and bird flight. Biomorphic gliders as biomorphic flight systems are a subset of biomorphic explorers. The multidisciplinary system concept of "Biomorphic...

Briefs : Physical Sciences
High-Heat-Flux Thermogravimetric Analysis With Radiography

A process and a laboratory setup to implement the process (see figure) have been devised to enable the acquisition of time-resolved data on the thermal decomposition of a specimen of a solid material exposed to a heat flux comparable to the heat flux in a typical rocket engine. The...

Briefs : Physical Sciences
Thermogravimetric Analysis With Laser Heating

Laser thermogravimetric analysis (laser TGA) is a technique that yields time-resolved data on the thermal decomposition of a specimen of a solid material exposed to a heat flux comparable to the heat flux in a typical rocket engine. Like the technique described in the preceding article, laser TGA...

Briefs : Mechanical & Fluid Systems
Stable Microwave-Beam-Riding Spacecraft

The work considers passive dynamic stability of sail craft, propelled by microwave beams. Such systems are under consideration as low-cost means of interstellar travel. Sail-craft shapes offering passive dynamic (neutral) stability are identified. Passive stability is a key mission-enabling attribute. Very...

Briefs : Physical Sciences
Ultralight Balloon Systems for Exploring Uranus and Neptune

A report proposes ultralight balloon systems to carry a 10-kg payload, including scientific instruments for exploring the atmospheres of Uranus and Neptune. The system masses to be transported to those planets would be kept low by not transporting balloon-inflating gases. Each...

Briefs : Materials
Foaming in Place for Outer-Space Applications

A report discusses the adaptation of foaming-in-place techniques and materials to outer-space applications. Foaming in place is used commercially in terrestrial sealing, insulating, bonding, and retrofitting applications. The room-temperature outer-space versions of foaming in place are...

Briefs : Motion Control
Advanced, Lightweight, Low-Power-Consumption Actuator Brake

An advanced, lightweight, low-power consumption brake has been developed to satisfy NASA's special requirements for use on actuators during spaceflight. This brake can increase the stopping, holding, and parking ability of a spacecraft while reducing its electrical power consumption....

Briefs : Information Technology
Partial Subtractive Dither for Lossy Data Compression

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.

Briefs : Electronics & Computers
Acquisition, Tracking, and Pointing in Optical Communication

A document in the form of lecture slides outlines a program of development of capabilities for acquisition of signals, tracking of signal sources, and pointing of transmitters and receivers in deep-space optical communications. Topics addressed on the first few slides include the...

Briefs : Information Technology
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...

Briefs : Electronics & Computers
Variable Telemetry Playback Rate for Increased Data Return

In a scheme to increase the overall data return from a phase-modulation, suppressed-carrier telemetry transmitter, the telemetry playback symbol rate is adjusted essentially continuously. More precisely, the playback symbol rate is adjusted frequently (as often as once per symbol...

Briefs : Information Technology
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...

Briefs : Test & Measurement
Measuring Contact Angles of a Sessile Drop and Imaging Convection Within It

Figure 1 depicts an apparatus that simultaneously and synchronously records magnified ordinary top-view video images and laser-shadowgraph video images of a sessile drop. The real-time values of contact angle and rate of evaporation of the drop as functions of time can...

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