April 2001

A new design for a complementary metal oxide/semiconductor (CMOS) snapshot imaging device of the photodiode-based, active-pixel-sensor (APS) type calls for features to prevent...

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....

Miniature high-resolution optical-absorption sensors for detecting trace amounts of chemical species of interest in gas and liquid samples are undergoing development. The transducer in...

A method of computing the speed at which to command an autonomous robotic vehicle to travel over rough terrain has been devised. The method amounts to a robotic implementation of the...

A proposed optoelectronic apparatus would perform the combined functions of a confocal microscope and a Raman spectrometer. It would be used to acquire Raman-spectral-image and/or...

A method of coarse alignment has been proposed for a primary telescope mirror that comprises multiple segments mounted on actuators that can be used to tilt and translate the segments to...

Experiments have shown that a highly oblate microspheroid made of low-dielectric-loss silica glass can function as a high-performance optical resonator. The shape of this resonator (see...

A method of estimating the state of contact between (1) the wheels of a robotic vehicle equipped with a rocker-bogey suspension and (2) the ground has been devised. The contact-state...

Briefs : Photonics/Optics
Software for Generating Mosaics of Astronomical Images

Software is being developed to "stitch" together multiple astronomical images of small, adjacent patches of the sky into a single mosaic image of a large portion of the sky. These mosaics make data from large areas of the sky readily available for efficient viewing of many types of...

Thin, initially transparent films made of variants of a polymeric cation-exchange material have been found to be useful for facilitating the luminescence detection and...

Briefs : Physical Sciences
High-Speed Image Compression via Optical Transformation

A proposed method of compressing image data would exploit the well-known capability of a converging lens to generate the Fourier transform of an image by purely optical means, in much less time than is needed to compute the discrete Fourier transform of a sampled image by use of digital...

Briefs : Physical Sciences
High-Speed Optical Image Compression at Lower Power

In an alternative to the optical image-compression method of the preceding article, the Fourier transform of the input image would be formed on the output plane by white-light holography, instead of by laser holography. The principal advantage of the alternative method would be decreased power...

Briefs : Information Technology
Algorithms for Recognition of Objects in Color Stereo Images

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...

Briefs : Information Technology
A Metric for Visual Quality of Digital Video

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...

Briefs : Software
Infrastructure Software for Mining Image Data Bases

Diamond Eye is a computer program that enables a user equipped with only a personal computer, web-browser software, and a network connection to analyze large collections of scientific image data. The system is based on a distributed applet/server architecture that provides platform-independent...

Briefs : Software
Software for Rapid Processing and Display of Earth Data

Digital Earth Workbench is a computer program that facilitates retrieval of Earth-related imagery and viewing of the imagery on either an ordinary computer video screen or a virtual-reality (head-tracked stereoscopic) display system. Examples of imagery that can be processed by

this...

Briefs : Electronics & Computers
Micromachined Broad Band Light Sources

A novel micromachined incandescent light source has been designed and fabricated to operate at temperatures exceeding 2,500 K. The high-temperature, tungsten filament-based source has a high-brightness, broad spectral band emission. The monolithic design allows for ease of incorporation with on-chip...

Briefs : Electronics & Computers
Automatic Bias Compensation in GPS Receivers

A technique of automatic bias compensation has been devised to correct errors caused by variations among electronic components in Global Positioning System (GPS) receivers that use the coarse/acquisition (C/A) GPS code. Even though there are large government and commercial markets for such GPS...

Briefs : Electronics & Computers
Ceramic Ribbons as Waveguides at Millimeter Wavelengths

Theoretical calculations verified by experiments have shown that suitably designed ribbons made of alumina can serve as low-loss dielectric waveguides for electromagnetic radiation at frequencies from 30 to 300 GHz. Prior to this development, low-loss waveguides for this frequency range...

Briefs : Software
Multithreading Program for Retrieval of Optical Phase Fields

A multithreading computer program performs phase-retrieval and -unwrapping calculations to extract accurate image phase maps from noisy image magnitude fields generated by adaptive optics. [As used here, "phase retrieval" signifies the calculation of phase map modulo 2µ, while...

Briefs : Software
Software for Analyzing Earth/Spacecraft Radio Interference

The Spectral Analysis Tool (SAT) computer program assists in analysis of interference between radio signals in Earth/spacecraft communications. SAT provides an easy-to-use interactive graphical interface with a menu for selecting among the following utility subprograms: an editor for...

"Smart coatings" denotes a class of high-temperature-resistant, multilayer, thin (total thickness < 10 µm) films that contain predominantly planar layers of sensor circuitry...

Briefs : Materials
Aggregate-Search Approach for Planning and Scheduling

Several algorithms developed for use in automated planning and scheduling of sets of interdependent activities employ aggregation techniques to increase the efficiency of searching for temporal assignments that are legal in the sense that they do not violate constraints. In the...

Briefs : Materials
Improvements in Electroformed Copper Alloys

Some success has been achieved in a development program directed toward improving the mechanical properties of electroformed copper-alloy structural components. Typical of such components are bundles of tubes and other heat-exchange devices that have complex shapes. Electroforming of copper alloys is...

Experiments have shown that an assembly of multiple free-piston Stirling engines can be designed and constructed in such a way as to both (1) make the vibrations of the engines...

An important secondary topic addressed in the research and development effort described in the preceding article is the use of artificial neural networks to improve the monitoring...

A special-purpose grinding tool and fixtures have been developed for reworking an edge of a seal surface on a nozzle-throat-support housing in a rocket engine (see Figure 1) to...

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...

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...

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...

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 : Electronics & Computers
CMOS Image Sensors Capable of Time-Delayed Integration

Complementary metal oxide/semiconductor (CMOS) image sensors would be capable of operation in a time-delayed-integration (TDI) mode. Heretofore, the only semiconductor electronic image sensors capable of TDI have been charge-coupled devices (CCDs), which have dominated the image-sensor...

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