Tech Briefs

Adaptive Modeling Language and Its Derivatives

Modeling language enables automation of the entire product development cycle.Adaptive Modeling Language (AML), developed by TechnoSoft, Inc., is the underlying language of an object-oriented, multidisciplinary, knowledge-based engineering framework. TechnoSoft is a leading provider of object-oriented modeling and simulation technology used for commercial and defense applications. AML offers an advanced modeling paradigm with an open architecture, enabling the automation of the entire product development cycle, integrating product configuration, design, analysis, visualization, production planning, inspection, and cost estimation.

Posted in: Information Sciences, Briefs

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Integrating Terrain Maps Into a Reactive Navigation Strategy

Traversability of terrain is taken into account as an integral part of navigation. An improved method of processing information for autonomous navigation of a robotic vehicle across rough terrain involves the integration of terrain maps into a reactive navigation strategy. Somewhat more precisely, the method involves the incorporation, into navigation logic, of data equivalent to regional traversability maps. The terrain characteristic is mapped using a fuzzy-logic representation of the difficulty of traversing the terrain. The method is robust in that it integrates a global path-planning strategy with sensor-based regional and local navigation strategies to ensure a high probability of success in reaching a destination and avoiding obstacles along the way. The sensor-based strategies use cameras aboard the vehicle to observe the regional terrain, defined as the area of the terrain that covers the immediate vicinity near the vehicle to a specified distance a few meters away. The method at an earlier stage of development was described in “Navigating a Mobile Robot Across Terrain Using Fuzzy Logic” (), NASA Tech Briefs, Vol. 27, No. 2 (February 2003), page 5a. A recent update on the terrain classification stage of the method was reported in “Quantifying Traversability of Terrain for a Mobile Robot” (), NASA Tech Briefs, Vol. 29, No. 7 (July 2005), page 56. To recapitulate: The basic building blocks of the method are three behaviors that focus on successively smaller spatial scales and are integrated (in the sense of blended) through gains or weighting factors to generate speed and steering commands. The weighting factors are generated by fuzzy logic rules that take account of the current status of the vehicle.

Posted in: Information Sciences, Briefs

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Reducing Centroid Error Through Model-Based Noise Reduction

Corrections are made for bias and noise.A method of processing the digitized output of a charge-coupled device (CCD) image detector has been devised to enable reduction of the error in computed centroid of the image of a point source of light. The method involves model-based estimation of, and correction for, the contributions of bias and noise to the image data. The method could be used to advantage in any of a variety of applications in which there are requirements for measuring precise locations of, and/or precisely aiming optical instruments toward, point light sources.

Posted in: Information Sciences, Briefs

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Templates for Fabricating Nanowire/Nanoconduit-Based Devices

Prior templating processes are being extended to finer spatial resolutions. An effort is underway to develop processes for making templates that could be used as deposition molds and etching masks in the fabrication of devices containing arrays of nanowires and/or nanoconduits. Examples of such devices include thermoelectric devices, nerve guidance scaffolds for nerve repair, photonic-band-gap devices, filters for trapping microscopic particles suspended in liquids, microfluidic devices, and size-selective chemical sensors. The technology is an extension of previous work conducted by JPL, UCSD (University of California, San Diego), and Paradigm Optics Inc., which developed a process to fabricate macroporous scaffolds for spinal-cord repair.

Posted in: Manufacturing & Prototyping, Briefs

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Measuring Vapors To Monitor the State of Cure of a Resin

Excess curing time would no longer be needed as margin against uncertainty. A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration(s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas:

Posted in: Manufacturing & Prototyping, Briefs

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Statistical Evaluation of Utilization of the ISS

PayLoad Utilization Modeler (PLUM) is a statistical-modeling computer program used to evaluate the effectiveness of utilization of the International Space Station (ISS) in terms of the number of research facilities that can be operated within a specified interval of time. PLUM is designed to balance the requirements of research facilities aboard the ISS against the resources available on the ISS. PLUM comprises three parts: an interface for the entry of data on constraints and on required and available resources, a database that stores these data as well as the program output, and a modeler. The modeler comprises two subparts: one that generates tens of thousands of random combinations of research facilities and another that calculates the usage of resources for each of those combinations. The results of these calculations are used to generate graphical and tabular reports to determine which facilities are most likely to be operable on the ISS, to identify which ISS resources are inadequate to satisfy the demands upon them, and to generate other data useful in allocation of and planning of resources.

Posted in: Software, Briefs

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Shuttle Data Center File- Processing Tool in Java

A Java-language computer program has been written to facilitate mining of data in files in the Shuttle Data Center (SDC) archives. This program can be executed on a variety of workstations or via Web-browser programs. This program is partly similar to prior C-language programs used for the same purpose, while differing from those programs in that it exploits the platform neutrality of Java in implementing several features that are important for analysis of large sets of time-series data. The program supports regular expression queries of SDC archive files, reads the files, interleaves the time-stamped samples according to a chosen output, then transforms the results into that format. A user can choose among a variety of output file formats that are useful for diverse purposes, including plotting, Markov modeling, multivariate density estimation, and wavelet multiresolution analysis, as well as for playback of data in support of simulation and testing.

Posted in: Software, Briefs

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