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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.

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At least 19 records

Resource Selection and Ranking

Surfer is an extensible framework for selecting and ranking grid resources. A resource is defined as anything that needs selecting such as compute resources, storage resources, and data resources.

Kolano, Paul↗

Surfer: An Extensible Pull-Based Framework for Resource Selection and Ranking

Grid computing aims to connect large numbers of geographically and organizationally distributed resources to increase computational power; resource utilization, and resource accessibility. In order to effectively utilize grids, users need to be connected to the best available resources at any given time. As grids are in constant flux, users cannot be expected to keep up with the configuration and status of the grid, thus they must be provided with automatic resource brokering for selecting and ranking resources meeting constraints and preferences they specify. This paper presents a new OGSI-compliant resource selection and ranking framework called Surfer that has been implemented as part of NASA's Information Power Grid (IPG) project. Surfer is highly extensible and may be integrated into any grid environment by adding information providers knowledgeable about that environment.

Zolano, Paul Z.↗

Comparative analysis of large antenna spacecraft using the ideas system

A Land Mobile Satellite System (LMSS), capable of providing mobile communications for commercial and government applications in nonmetropolitan areas of the continental U.S. and Canada as an augmentation to existing and planned terrestrial systems, is being studied. The satellite system would provide 'narrow band' telecommunications services such as mobile radio, telephone, dispatch, safety, and special radio services, and thin-route fixed telephone and data services in the 806-890 MHz band and continuous emergency beacon monitoring in the 406-406.1 MHz band. A single Shuttle launch with an upper stage orbital transfer system would place the LMSS spacecraft in geosynchronous orbit over the continental U.S. in 1995 with a 10-year lifetime. The present investigation has the objective to evaluate, compare, and rank selected spacecraft concepts, to suggest design improvement to the individual concepts, and to identify technology needs.

Garrett, L. B.↗

Efficient File Sharing by Multicast - P2P Protocol Using Network Coding and Rank Based Peer Selection

In this work, we consider information dissemination and sharing in a distributed peer-to-peer (P2P highly dynamic communication network. In particular, we explore a network coding technique for transmission and a rank based peer selection method for network formation. The combined approach has been shown to improve information sharing and delivery to all users when considering the challenges imposed by the space network environments.

military↗

Efficient Simulation Budget Allocation for Selecting an Optimal Subset

We consider a class of the subset selection problem in ranking and selection. The objective is to identify the top m out of k designs based on simulated output. Traditional procedures are conservative and inefficient. Using the optimal computing budget allocation framework, we formulate the problem as that of maximizing the probability of correc tly selecting all of the top-m designs subject to a constraint on the total number of samples available. For an approximation of this corre ct selection probability, we derive an asymptotically optimal allocat ion and propose an easy-to-implement heuristic sequential allocation procedure. Numerical experiments indicate that the resulting allocatio ns are superior to other methods in the literature that we tested, and the relative efficiency increases for larger problems. In addition, preliminary numerical results indicate that the proposed new procedur e has the potential to enhance computational efficiency for simulation optimization.

Chen, Chun-Hung↗

Advanced stratified charge rotary aircraft engine design study

A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

Badgley, P.↗

Space Tug Docking Study. Volume 1: Executive Summary

Results of a detailed systems analysis of the entire rendezvous and docking operation to be performed by the all-up space tug are presented. Specific areas investigated include: generating of operational requirements and a data base of candidate operational techniques and subsystem mechanizations; selection and ranking of integrated system designs capable of meeting the requirements generated; and definition of this simulation/demonstration program required to select and prove the most effective manual, autonomous, and hybrid rendezvous and docking systems.

Source record↗

The use of multispectral sensing techniques to detect ponderosa pines trees under stress from insects or diseases

The detection of stress induced by bark beetles in conifers is reviewed in two sections: (1) the analysis of very small scale aerial photographs taken by NASA's RB-57F aircraft on August 10, 1969, and (2) the analysis of multispectral imagery obtained by the optical-mechanical line scanner. Underexposure of all films taken from the RB-57 aircraft and inadequate flight coverage prevented drawing definitive conclusions regarding optimum scales and film combinations to detect the discolored infestations. Preprocessing of the scanner signals by both analog and digital computers improved the accuracy of target recognition. Selection and ranking of the best channels for signature recognition was the greatest contribution of digital processing. Improvements were made in separating hardwoods from conifers and old-kill pine trees from recent discolored trees and from healthy trees, but accuracy of detecting the green infested trees is still not acceptable on either the SPARC or thermal-contouring processor. From six years of experience in processing line scan data it is clear that the greatest gain in previsual detection of stress will occur when registered multispectral data from a single aperture or common instantaneous field of view scanner system can be collected and processed.

Heller, R. C.↗

Winter Simulation Conference, Miami Beach, Fla., December 4-6, 1978, Proceedings. Volumes 1 & 2

The papers report on the various aspects of simulation such as random variate generation, simulation optimization, ranking and selection of alternatives, model management, documentation, data bases, and instructional methods. Simulation studies in a wide variety of fields are described, including system design and scheduling, government and social systems, agriculture, computer systems, the military, transportation, corporate planning, ecosystems, health care, manufacturing and industrial systems, computer networks, education, energy, production planning and control, financial models, behavioral models, information systems, and inventory control.

Highland, H. J.↗

Friction-Testing Machine

Testing machine evaluates wear and ignition characteristics of materials in rubbing contact. Offers advantages over other laboratory methods of measuring wear because it simulates operating conditions under which material will actually be used. Machine used to determine wear characteristics, rank and select materials for service with such active oxidizers as oxygen, halogens, and oxides of nitrogen, measure wear characteristics, and determine coefficients of friction.

Benz, F. J.↗

Experiments in model-based matching using a relational pyramid representation

The relational pyramid representation is a hierarchical relational description of an object that can be used in recognition and pose estimation. In this representation, primitive features appear at the bottom of the pyramid, relations among primitives appear at level one, and, in general, relations among lower-level structures appear at the levels above the levels in which these structures were defined. A pose-estimation system is constructed that uses the relational pyramid representation for the view classes of a 3D object and for the description of the unknown view of an object extracted from an image. A previously described system uses summary information to rank and select view classes to which the unknown view is compared. This paper describes a best-first search procedure to find correspondences between the selected view class pyramid and the image pyramid.

Chu, Nancy T.↗

NASA Tech Briefs, June 2007

Topics covered include: High-Accuracy, High-Dynamic-Range Phase-Measurement System; Simple, Compact, Safe Impact Tester; Multi-Antenna Radar Systems for Doppler Rain Measurements; 600-GHz Electronically Tunable Vector Measurement System; Modular Architecture for the Measurement of Space Radiation; VLSI Design of a Turbo Decoder; Architecture of an Autonomous Radio Receiver; Improved On-Chip Measurement of Delay in an FPGA or ASIC; Resource Selection and Ranking; Accident/Mishap Investigation System; Simplified Identification of mRNA or DNA in Whole Cells; Printed Multi-Turn Loop Antennas for RF Biotelemetry; Making Ternary Quantum Dots From Single-Source Precursors; Improved Single-Source Precursors for Solar-Cell Absorbers; Spray CVD for Making Solar-Cell Absorber Layers; Glass/BNNT Composite for Sealing Solid Oxide Fuel Cells; A Method of Assembling Compact Coherent Fiber-Optic Bundles; Manufacturing Diamond Under Very High Pressure; Ring-Resonator/Sol-Gel Interferometric Immunosensor; Compact Fuel-Cell System Would Consume Neat Methanol; Algorithm Would Enable Robots to Solve Problems Creatively; Hypothetical Scenario Generator for Fault-Tolerant Diagnosis; Smart Data Node in the Sky; Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers; Update on Controlling Herds of Cooperative Robots; and Simulation and Testing of Maneuvering of a Planetary Rover.

Source record↗

Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose Requirements: Why is this an "Epic Challenge" for Long-Term Manned Interplanetary Flight

Outline of presentation: (1) Radiation Shielding Concepts and Performance - Galactic Cosmic Rays (GCRs) (1a) Some general considerations (1b) Galactic Cosmic Rays (2)GCR Shielding I: What material should I use and how much do I need? (2a) GCR shielding materials design and verification (2b) Spacecraft materials point dose cosmic ray shielding performance - hydrogen content and atomic number (2c) Accelerator point dose materials testing (2d) Material ranking and selection guidelines (2e) Development directions and return on investment (point dose metric) (2f) Secondary particle showers in the human body (2f-1) limited return of investment for low-Z, high-hydrogen content materials (3) GCR shielding II: How much will it cost? (3a) Spacecraft design and verification for mission radiation dose to the crew (3b) Habitat volume, shielding areal density, total weight, and launch cost for two habitat volumes (3c) It's All about the Money - Historical NASA budgets and budget limits (4) So, what can I do about all this? (4a) Program Design Architecture Trade Space (4b) The Vehicle Design Trade Space (4c) Some Near Term Recommendations

Koontz, Steven↗