Keyword: Optimization

Briefs: Materials
Probabilistic Multi-Factor Interaction Model for Complex Material Behavior

Complex material behavior is represented by a single equation of product form to account for interaction among the various factors. The factors are selected by the physics of the problem and the environment that the model is to represent. For example, different factors...

Articles: Lighting

We normally think of ‘white’ light as being comprised of all wavelengths in the visible spectrum, or at least of being comprised of red, green, and blue. However, white LEDs emit...

Articles: Lighting

Two overriding issues should be considered when driving high-brightness (HB) LEDs. The first is to ensure that a fairly constant current is available with minimal variation,...

Briefs: Information Technology

A methodology and software to implement the methodology are under development in an effort to automate at least part of the process of designing integrated-circuit (IC) chips that...

Articles: Motion Control

The economic realities of the industrial marketplace are driving machine builders and integrators to get creative and build more intelligence into their machines in order to increase...

Articles: Software

In our annual poll of executives at leading design and virtual prototyping software companies, we found that in difficult economic times, providing...

Briefs: Semiconductors & ICs
Reconfigurable, Bi-Directional Flexfet Level Shifter for Low- Power, Rad-Hard Integration

Two prototype Reconfigurable, Bidirectional Flexfet Level Shifters (ReBiLS) have been developed, where one version is a stand-alone component designed to interface between external low voltage and high voltage, and the other version is an embedded...

Briefs: Physical Sciences
Dual-Channel Multi-Purpose Telescope

A dual-channel telescope allows for a wide-field telescope design with a good, narrow field channel of fewer surfaces for shorter-wavelength or planet-finding applications. The design starts with a Korsch three-mirror-anastigmat (TMA) telescope that meets the mission criteria for image quality over a wide...

Briefs: Information Technology
Supply-Chain Optimization Template

The Supply-Chain Optimization Tem - plate (SCOT) is an instructional guide for identifying, evaluating, and optimizing (including re-engineering) aerospace-oriented supply chains. The SCOT was derived from the Supply Chain Council’s Supply-Chain Operations Reference (SCC SCOR) Model, which is more generic and...

Articles: Motion Control

A new category of IC called an intelligent motor controller (IMC) is evolving that simplifies the task of designing high performance motor control drives. IMCs are dedicated, high-speed...

Briefs: Software
Determining Spacecraft Reaction Wheel Friction Parameters

Software was developed to characterize the drag in each of the Cassini spacecraft’s Reaction Wheel Assemblies (RWAs) to determine the RWA friction parameters. This tool measures the drag torque of RWAs for not only the high spin rates (>250 RPM), but also the low spin rates...

Briefs: Physical Sciences

Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each...

Briefs: Semiconductors & ICs

The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy...

Articles: Software

NASA’s Glenn Research Center (Cleveland, OH) and Boeing employees have won the 2008 NASA Software of the Year Award for the development of a general-purpose program used to perform trajectory...

Briefs: Software
Mission Operations and Navigation Toolkit Environment

MONTE (Mission Operations and Navigation Toolkit Environment) Release 7.3 is an extensible software system designed to support trajectory and navigation analysis/design for space missions. MONTE is intended to replace the current navigation and trajectory analysis software systems, which, at...

Briefs: Information Technology
Planning Complex Sequences Using Compressed Representations

A method that notably includes the use of compressed representations interleaved with non-compressed (time-line) representations of a general scheduling problem has been conceived as a means of increasing, by orders of magnitude, the speeds of computations needed for scheduling complex...

Briefs: Electronics & Computers
Li/CFₓ Cells Optimized for Low-Temperature Operation

Several prior developments are combined.

Some developments reported in prior NASA Tech Briefs articles on primary electrochemical power cells containing lithium anodes and fluorinated carbonaceous (CFx) cathodes have been combined to yield a product line of cells optimized...

Briefs: Electronics & Computers
Improved-Bandwidth Transimpedance Amplifier

The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside...

Briefs: Information Technology

A computational method and system based on a hybrid of an artificial neural network (NN) and a support vector machine (SVM) (see figure) has been conceived as a means of maximizing or...

Articles: Electronics & Computers

The increasing emphasis on green technologies has focused more attention on low power design. Microcontroller vendors are responding by increasing their offerings of ultra low power devices that...

Briefs: Software
Spreadsheets for Analyzing and Optimizing Space Missions

XCALIBR (XML Capability Analysis LIBRary) is a set of Extensible Markup Language (XML) database and spreadsheet-based analysis software tools designed to assist in technology-return-on-investment analysis and optimization of technology portfolios pertaining to outer- space missions....

Briefs: Information Technology
Using Covariance Analysis To Assess Pointing Performance

A Pointing Covariance Analysis Tool (PCAT) has been developed for evaluating the expected performance of the pointing control system for NASA’s Space Interferometry Mission (SIM). The SIM pointing control system is very complex, consisting of multiple feedback and feedforward loops, and...

Briefs: Electronics & Computers

A monolithic silicon-on-insulator (SOI) complementary metal oxide/ semiconductor (CMOS) image-detecting integrated circuit of the active-pixel-sensor type, now undergoing development, is...

Briefs: Manufacturing & Prototyping

An improved photoresist-coating technique has been developed for use in the fabrication of carbon-nanotube- (CNT)- based field emitters of the type described in “Fabrication of...

Briefs: Physical Sciences

An alternative design concept for nuclear thermal rocket engines for interplanetary spacecraft calls for the use of grooved-ring fuel elements. Beyond spacecraft rocket engines, this...

Eye on Innovation: Software

When it comes to testing products for long-term durability, shock exposure survival, or accelerated life testing, the classic technique most engineers turn to is vibration testing with a...

Briefs: Information Technology

An improved method of model-based diagnosis of a complex engineering system is embodied in an algorithm that involves considerably less computation than do prior such algorithms....

Briefs: Information Technology

A computationally efficient method has been developed to enable optimization of the placement of sensors for the purpose of diagnosis of a complex engineering system (e.g., an aircraft or...

Application Briefs: Motion Control

Just a few years ago, the use of computational fluid dynamics (CFD) in most aerospace companies was restricted to pure research or troubleshooting problems with existing designs. But in the...