Information Technology & Software

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 advances in Internet software and in distributed object-oriented software to overcome the technological obstacles to integration of heterogeneous computing environments. The approach taken in this development involves refocusing effort on the development of metadata, which would be used to describe the available data resources and to support interoperability of computing systems. The software would manage a hierarchical conglomerate of data-set-resource definitions that would make it possible for application programs to locate the data that they require, without advance knowledge of which computer data systems and catalogs to search. This software would utilize the Extensible Markup Language (XML) and the Common Object Request Broker Architecture (CORBA) to support for interchange of data among heterogeneous sources. CORBA would enable over-the-wire exchange of XML-based profiles that would contain descriptions of data stored in remote computer systems.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Data acquisition and handling

Wavelet Analysis To Predict Limit Cycles

It is possible to predict the airspeed of onset of dangerous oscillations.

A method to predict the onset of a limit cycle for an aeroelastic testbed has been developed. The prediction is based on wavelet processing of measurement data that have been recorded under various flight conditions. The method has been considered for only a small testbed; however, the concepts may lead to techniques that could assist in prediction of the aeroelastic behaviors of aircraft during flight testing.

Posted in: Briefs, Information Sciences, Measurements, Flight tests

Program Automates Management of IBM VM Computer Systems

The VM Automated System computer program was developed to satisfy a need for efficient management of operations in a large client/server computer network that includes multiple mainframe computers and multiple local-area subnetworks. Functions performed by the program include the following:

Posted in: Briefs, Information Sciences, Computer software and hardware, Systems management, Automation

Java Implementation of Information-Sharing Protocol

The Java-language ISPresso software enables real-time access to mission data via home and office personal computers.

Johnson Space Center's (JSC's) growing operations community requires new ways to distribute and process mission information. The Mission Control Center uses flight-control application programs based on an information-sharing protocol (ISP) to process and distribute real-time mission telemetry, trajectory, and computation data. ISP application programs provide multiple users synchronous, rapid access to mission data and programs. The ISPresso ISP software package is designed in Java, which is rapidly becoming the language of choice because of its ability to work on almost any platform. ISPresso plays a substantial role in the remote-access platforms now being implemented for space-shuttle and space-station operations and is used for Hubble Space Telescope operations. The portability of ISPresso enables deployment of mission-data-processing application programs to desktop computers and makes it possible to package application software for convenient access through web browsers. Such accessibility will prove useful in many additional process-control settings, from powerplants to all types of manufacturing.

Posted in: Briefs, Information Sciences, Communication protocols, Computer software and hardware, Spacecraft

Electronic Bulletin Board Publishes Schedules in Real Time

Real Time Schedule Publisher (RTSP) is a computer program that generates a report of the current schedules of as many as about 25 users within an organization. The report is refreshed every 5 minutes and displayed in a common area on a flat-panel computer monitor that serves as an "in/out" bulletin board. The report is displayed in a five-column tabular format and includes color-coded legends that describe the status (with respect to availability) of each user. Each row of the table reflects a single event for a single user; the five columns represent, respectively, the name of the user, the event start time, the event end time, the location, and the subject. The display also includes the current date, day of the week, and time. In addition to the common display, an interactive view of the scheduling information is available, through a standard web browser, on any desktop computer connected to the organization's computer network. The interactive view provides an interface for administering users' accounts. RTSP is based on the active-server architecture of the Windows NT Server operating system and is integrable with similarly based commercial-off-the-shelf scheduling programs.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Data management, Systems management

Digital Library of NACA Reports

Aging paper NACA documents are scanned, then disseminated in electronic form.

The NACA Technical Report Server (NACATRS) is both a node in the NASA Technical Report Server and a stand-alone World Wide Web (WWW) site. The NACATRS is dedicated to the preservation and dissemination of reports produced by the National Advisory Committee for Aeronautics (NACA).

Posted in: Briefs, TSP, Information Sciences, Internet, Data management

Finding Known Shapes in an Image by Pruning Parameter Space

This method is both efficient and robust.

An improved method of processing two- and three-dimensional image data to locate known shapes called "geometric primitives" involves (1) extraction of edges and other relevant image features and (2) performing a hierarchical search, in a space of parameters of equations that describe the shapes of the features, for those parameters that represent the geometric primitives. This method is inspired by prior object-recognition methods in which parameter spaces are recursively divided and pruned. The most closely related prior methods of this type are based on variations of the Hough transform. Whereas the prior methods have generally offered robustness or computational efficiency but not both, this method offers both, along with other advantages: It enables the efficient and robust extraction of geometric primitives from noisy and incomplete data that include many distracting data, without need for initial estimates of the locations of the geometric primitives.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Data acquisition and handling, Imaging and visualization

Program for Displaying Large, Coregistered Images

DataSlate is an easy-to-use Java-language computer program for displaying coregistered raster images representing large sets of data. The program includes a main viewing module that can display image data that have been converted into a special DataSlate format called "SimpleStruct" by use of an Interactive Data Language program called "SimpleGen." The conversion into SimpleStruct optimizes the organization of the data in the sense that it simplifies any computations that must be done subsequently during perusal of the data. DataSlate enables the user to navigate very large sets of scientific data visually: DataSlate presents a slatelike user interface with simple buttons to select sets of data or to zoom in or out. The user can scroll through a set of data by simply dragging a cursor on a screen. DataSlate can also dynamically load plug-in software tools (e.g., for measuring lengths, angles, areas, or geographic coordinates) at run time. DataSlate can also traverse coregistered collections of data and can present a second data channel in a window on the screen to facilitate correlation or comparison of two sets of data (e.g., from two sensors and/or taken at different times).

Posted in: Briefs, Information Sciences, Computer software and hardware, Imaging and visualization, Human machine interface (HMI), Data management

RS Forward Error Correction for Variable-Length Frames

Method accommodates dynamically varying frame length.

A method of forward error correction by Reed-Solomon (RS) coding has been devised to increase the link margins of data-communication systems that must handle variable-length frames or packets of data. Heretofore, RS coding has involved fixed-length blocks: In order to encode variable-length frames, it has been necessary to (a) choose a fixed block length equal to a multiple of some given block length and greater than or equal to the length of the longest variable-length frame and (b) in the case of a frame shorter than the fixed block length, pad or fill the remainder of the block with extra bytes. This is very inefficient because the fill conveys no useful information, and any errors in the fill diminish the overall coding gain by using up some or all of the available error-correction capacity.

Posted in: Briefs, Information Sciences, Communication protocols, Data exchange

Fast NRZLM Encoding and Decoding Algorithm

Byte-oriented algorithms save time.

A recently developed algorithm saves encoding and decoding time in the operation of data-communication systems that utilize the NRZM code, which is derived from the better-known non-return-to-zero-level (NRZL) code. This algorithm utilizes lookup tables that contain the results of routine encoding and decoding computations that would otherwise have to be performed repeatedly.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Communication protocols, Cryptography

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