Home

Encryption for Remote Control via Internet or Intranet

This protocol provides security against control by unauthorized users.

Posted in: Briefs

Read More >>

Scheme for Entering Binary Data Into a Quantum Computer

This could be an important step toward making quantum computing practical.

Posted in: Briefs, TSP

Read More >>

Simulation of Laser Cooling and Trapping in Engineering Applications

This design instrument shows good agreement with experimental measurements. An advanced computer code is undergoing development for numerically simulating laser cooling and trapping of large numbers of atoms. The code is expected to be useful in practical engineering applications and to contribute to understanding of the roles that light, atomic collisions, background pressure, and numbers of particles play in experiments using laser-cooled and -trapped atoms. The code is based on semiclassical theories of the forces exerted on atoms by magnetic and optical fields. Whereas computer codes developed previously for the same purpose account for only a few physical mechanisms, this code incorporates many more physical mechanisms (including atomic collisions, sub-Doppler cooling mechanisms, Stark and Zeeman energy shifts, gravitation, and evanescent-wave phenomena) that affect laser-matter interactions and the cooling of atoms to submillikelvin temperatures. Moreover, whereas the prior codes can simulate the interactions of at most a few atoms with a resonant light field, the number of atoms that can be included in a simulation by the present code is limited only by computer memory. Hence, the present code represents more nearly completely the complex physics involved when using laser-cooled and -trapped atoms in engineering applications.

Posted in: Photonics, Briefs, TSP

Read More >>

Domain Compilation for Embedded Real-Time Planning

Robustness is increased at the price of a moderate increase in complexity.

Posted in: Briefs, TSP

Read More >>

Method of Real-Time Principal-Component Analysis

Hardware can be simplified. Dominant element-based gradient descent and dynamic initial learning rate (DOGEDYN) is a method of sequential principal component analysis (PCA) that is well suited for such applications as data compression and extraction of features from sets of data. In comparison with a prior method of gradient-descent based sequential PCA, this method offers a greater rate of learning convergence. Like the prior method, DOGEDYN can be implemented in software. However, the main advantage of DOGEDYN over the prior method lies in the facts that it requires less computation and can be implemented in simpler hardware. It should be possible to implement DOGEDYN in compact, lowpower, very-large-scale integrated (VLSI) circuitry that could process data in real time.

Posted in: Briefs, TSP

Read More >>

Insect-Inspired Flight Control for Unmanned Aerial Vehicles

Relatively simple sensory and computing systems would generate remarkably effective control in flight to allow close-up approach to hard terrain. Flight-control and navigation systems inspired by the structure and function of the visual system and brain of insects have been proposed for a class of developmental miniature robotic aircraft called “biomorphic flyers” described earlier in “Development of Biomorphic Flyers” (), NASA Tech Briefs, Vol. 28, No. 11 (November 2004), page 54. These form a subset of biomorphic explorers, which, as reported in several articles in past issues of NASA Tech Briefs [“Biomorphic Explorers” (), Vol. 22, No. 9 (September 1998), page 71; “Bio-Inspired Engineering of Exploration Systems” (), Vol. 27, No. 5 (May 2003), page 54; and “Cooperative Lander-Surface/Aerial Microflyer Missions for Mars Exploration” (), Vol. 28, No. 5 (May 2004), page 36], are proposed small robots, equipped with microsensors and communication systems, that would incorporate crucial functions of mobility, adaptability, and even cooperative behavior. These functions are inherent to biological organisms but are challenging frontiers for technical systems. Biomorphic flyers could be used on Earth or remote planets to explore otherwise difficult or impossible to reach sites. An example of an exploratory task of search/surveillance functions currently being tested is to obtain high-resolution aerial imagery, using a variety of miniaturized electronic cameras.

Posted in: Briefs, TSP

Read More >>

Semantic Metrics for Analysis of Software

These metrics represent a more human oriented view of software. A recently conceived suite of object-oriented software metrics focus is on semantic aspects of software, in contradistinction to traditional software metrics, which focus on syntactic aspects of software. Semantic metrics represent a more human-oriented view of software than do syntactic metrics. The semantic metrics of a given computer program are calculated by use of the output of a knowledge-based analysis of the program, and are substantially more representative of software quality and more readily comprehensible from a human perspective than are the syntactic metrics.

Posted in: Briefs, TSP

Read More >>

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