Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “data flow”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

A flexible approach to an Operational Land Observing System

This paper presents a concept for an Operational Land Observing System (OLOS) formulated to satisfy a broad spectrum of perceived user needs for a diverse discipline community. The concept formulated will allow continuous orthographic imaging across multiple spectral bands, near-global stereoscopic imaging, and next-day oblique imaging of any desired spot on earth. Imaging parameters will be adaptable to known phenomena characteristics to facilitate information extraction including optional onboard theme selection. The conceptual system will provide 6- to 12-hour quick-look capability, 48-hour turnaround on all standard imaging products, and a guaranteed data flow schedule reliability for 10 to 20 years. A fleet of successive operational satellites will be used.

Driver, J. M.↗
NASA NTRS1981

Space platforms for science and applications

It is pointed out that space platforms offer a flexible and cost-effective evolutionary approach to conducting science and applications missions of several months' duration and can pave the way for major manned orbital facilities. General-purpose Low-Earth-Orbit space platforms are made possible by the Space Transportation System. Such platforms could remain in orbit for many years serviced as needed by the Shuttle. Attention is given to a Power System Platform, aspects of communications and data handling, stability and control, system and subsystem capability, a dynamics-analysis model of an expanded platform, command and data flow for a space platform, comparative costs of flying a pallet-size payload, a continually mannable Science and Applications Manned Space Platform, and a scenario of how the space platform might evolve.

Snoddy, W. C.↗
NASA NTRS1979

Integrated testing and verification system for research flight software design document

The NASA Langley Research Center is developing the MUST (Multipurpose User-oriented Software Technology) program to cut the cost of producing research flight software through a system of software support tools. The HAL/S language is the primary subject of the design. Boeing Computer Services Company (BCS) has designed an integrated verification and testing capability as part of MUST. Documentation, verification and test options are provided with special attention on real time, multiprocessing issues. The needs of the entire software production cycle have been considered, with effective management and reduced lifecycle costs as foremost goals. Capabilities have been included in the design for static detection of data flow anomalies involving communicating concurrent processes. Some types of ill formed process synchronization and deadlock also are detected statically.

Taylor, R. N.↗
NASA NTRS1980

Future integrated design process

The design process is one of the sources used to produce requirements for a computer system to integrate and manage product design data, program management information, and technical computation and engineering data management activities of the aerospace design process. Design activities were grouped chronologically and explored for activity type, activity interface, data quantity, and data flow. The work was based on analysis of the design process of several typical aerospace products, including both conventional and supersonic airplanes and a hydrofoil design. Activities examined included research, preliminary design, detail design, manufacturing interface, product verification, and product support. The design process was then described in an IPAD environment--the future.

Meyer, D. D.↗
NASA NTRS1979

SKYMAP system description: Star catalog data base generation and utilization

The specifications, design, software description, and use of the SKYMAP star catalog system are detailed. The SKYMAP system was developed to provide an accurate and complete catalog of all stars with blue or visual magnitudes brighter than 9.0 for use by attitude determination programs. Because of the large number of stars which are brighter than 9.0 magnitude, efficient techniques of manipulating and accessing the data were required. These techniques of staged distillation of data from a Master Catalog to a Core Catalog, and direct access of overlapping zone catalogs, form the basis of the SKYMAP system. The collection and tranformation of data required to produce the Master Catalog data base is described. The data flow through the main programs and levels of star catalogs is detailed. The mathematical and logical techniques for each program and the format of all catalogs are documented.

Gottlieb, D. M.↗
NASA NTRS1983

Large space structures control algorithm characterization

Feedback control algorithms are developed for sensor/actuator pairs on large space systems. These algorithms have been sized in terms of (1) floating point operation (FLOP) demands; (2) storage for variables; and (3) input/output data flow. FLOP sizing (per control cycle) was done as a function of the number of control states and the number of sensor/actuator pairs. Storage for variables and I/O sizing was done for specific structure examples.

Fogel, E.↗
NASA NTRS1982

LANDSAT-D ground segment operations plan, revision A

The basic concept for the utilization of LANDSAT ground processing resources is described. Only the steady state activities that support normal ground processing are addressed. This ground segment operations plan covers all processing of the multispectral scanner and the processing of thematic mapper through data acquisition and payload correction data generation for the LANDSAT 4 mission. The capabilities embedded in the hardware and software elements are presented from an operations viewpoint. The personnel assignments associated with each functional process and the mechanisms available for controlling the overall data flow are identified.

Evans, B.↗
NASA NTRS1980

Soil Moisture Project Evaluation Workshop

Approaches planned or being developed for measuring and modeling soil moisture parameters are discussed. Topics cover analysis of spatial variability of soil moisture as a function of terrain; the value of soil moisture information in developing stream flow data; energy/scene interactions; applications of satellite data; verifying soil water budget models; soil water profile/soil temperature profile models; soil moisture sensitivity analysis; combinations of the thermal model and microwave; determing planetary roughness and field roughness; how crust or a soil layer effects microwave return; truck radar; and truck/aircraft radar comparison.

Gilbert, R. H.↗
NASA NTRS1983

Parallel processing in a host plus multiple array processor system for radar

Host plus multiple array processor architecture is demonstrated to yield a modular, fast, and cost-effective system for radar processing. Software methodology for programming such a system is developed. Parallel processing with pipelined data flow among the host, array processors, and discs is implemented. Theoretical analysis of performance is made and experimentally verified. The broad class of problems to which the architecture and methodology can be applied is indicated.

Barkan, B. Z.↗
NASA NTRS1983

High-accuracy global time and frequency transfer with a space-borne hydrogen maser clock

A proposed system for high-accuracy global time and frequency transfer using a hydrogen maser clock in a space vehicle is discussed. Direct frequency transfer with a accuracy of 10 to the minus 14th power and time transfer with an estimated accuracy of 1 nsec are provided by a 3-link microwave system. A short pulse laser system is included for subnanosecond time transfer and system calibration. The results of studies including operational aspects, error sources, data flow, system configuration, and implementation requirements for an initial demonstration experiment using the Space Shuttle are discussed.

Decher, R.↗
NASA NTRS1983

The IRAS telescope

The IRAS telescope is described in terms of its system configuration and physical characteristics, subsystem functions and descriptions, and performance characteristics. The mission and the configuration are reviewed briefly, and the major functional components of the telescope are described, including the focal plane assembly, the optics, the electronics, the cryogenics, and the thermal control. Exploded and cross-sectional views and block diagrams are presented for the telescope system configuration, focal plane assembly, infrared subarray module, optical subsystem, infrared channel data flow, and main cryogen dewar. The telescope physical characteristics are listed. The performance characteristics are listed and discussed, including the spectral response, sensitivity, optical quality, and photometric accuracy. Relative system spectral response curves for the infrared bands are shown.

Irace, W.↗
NASA NTRS1983

Development and use of an integrated analysis capability

The paper describes a multi-discipline integrated analysis capability, designed to aid the engineering community in coupling of existing modules and in handling of the associated software and data. This capability consists of an executive program which manages tasks and data, a number of technical modules, graphics and special purpose modules, inter-module data flow interfaces, and associated user documentation. The current implementation provides specific modules and coupled solution paths for the thermal, structures and controls technologies. However, the system has been designed to serve also as a framework into which user groups may incorporate other modules and technologies. Details of the system architecture are discussed, in the context of the major design decisions and the software development and usage experience. The paper provides a brief discussion of some other integrated systems which are available or under development.

Vos, R. G.↗
NASA NTRS1983

Triangular system solutions on an optical systolic processor

It is noted that the simplified system of equations presented by Casasent and Ghosh (1983) can also be solved optically. One realization of this is described, with attention given to data flow and speed for the case of a lower triangular system of equations. The solution of an upper triangular system of equations can be handled in analogous fashion. The problem requires a matrix-vector processor. Only one carrier frequency input to the acoustooptic cell and only one output detector are used. To multiply a matrix by a vector in this system, the time-multiplexed vector elements are fed into the acoustooptic cell.

Ghosh, A.↗
NASA NTRS1983

An Attached Payload Operations Center (APOC) at the Goddard Space Flight Center (GSFC), volume 1

A management overview of the Attached Payload Operations Center (APOC) functional requirements and design are presented. The rationale for developing the APOC concept and the assumptions utilized are presented. A summary of the concept complete with major functional areas and associated data flows is provided. The attributes of this concept are formalized and the necessary resources needed for its development and operation presented.

Source record↗
NASA NTRS1984

Optical systolic solutions of linear algebraic equations

The philosophy and data encoding possible in systolic array optical processor (SAOP) were reviewed. The multitude of linear algebraic operations achievable on this architecture is examined. These operations include such linear algebraic algorithms as: matrix-decomposition, direct and indirect solutions, implicit and explicit methods for partial differential equations, eigenvalue and eigenvector calculations, and singular value decomposition. This architecture can be utilized to realize general techniques for solving matrix linear and nonlinear algebraic equations, least mean square error solutions, FIR filters, and nested-loop algorithms for control engineering applications. The data flow and pipelining of operations, design of parallel algorithms and flexible architectures, application of these architectures to computationally intensive physical problems, error source modeling of optical processors, and matching of the computational needs of practical engineering problems to the capabilities of optical processors are emphasized.

Neuman, C. P.↗
NASA NTRS1984

Development and Evaluation of a Performance Modeling Flight Test Approach Based on Quasi Steady-State Maneuvers

The development, implementation and flight test evaluation of a performance modeling technique which required a limited amount of quasisteady state flight test data to predict the overall one g performance characteristics of an aircraft. The concept definition phase of the program include development of: (1) the relationship for defining aerodynamic characteristics from quasi steady state maneuvers; (2) a simplified in flight thrust and airflow prediction technique; (3) a flight test maneuvering sequence which efficiently provided definition of baseline aerodynamic and engine characteristics including power effects on lift and drag; and (4) the algorithms necessary for cruise and flight trajectory predictions. Implementation of the concept include design of the overall flight test data flow, definition of instrumentation system and ground test requirements, development and verification of all applicable software and consolidation of the overall requirements in a flight test plan.

Yechout, T. R.↗
NASA NTRS1984

Fault tolerant architectures for integrated aircraft electronics systems, task 2

The architectural basis for an advanced fault tolerant on-board computer to succeed the current generation of fault tolerant computers is examined. The network error tolerant system architecture is studied with particular attention to intercluster configurations and communication protocols, and to refined reliability estimates. The diagnosis of faults, so that appropriate choices for reconfiguration can be made is discussed. The analysis relates particularly to the recognition of transient faults in a system with tasks at many levels of priority. The demand driven data-flow architecture, which appears to have possible application in fault tolerant systems is described and work investigating the feasibility of automatic generation of aircraft flight control programs from abstract specifications is reported.

Levitt, K. N.↗