NASA Scientific and Technical Aerospace Reports

20040111478 Cornell Univ., Ithaca, NY
Self-Configuring Wireless Transmission and Decentralized Data Processing for Generic Sensor Networks
Wicker, Steven B.; Jul. 2004; 38 pp.; In English; Original contains color illustrations
Contract(s)/Grant(s): F30602-00-2-0558; DARPA ORDER-K257; Proj-K257
Report No.(s): AD-A425425; AFRL-IF-RS-TR-2004-204; No Copyright; Avail: CASI; A03, Hardcopy
This report describes the results of the Self- Configuring Wireless Sensor Network effort at Cornell University, funded
under the DARPA SensIT program. The primary goal of this effort was the development of core technologies for large sensor
networks that are truly self-configuring. Such networks should not depend on fixed emplacements or predefined topologies.
Control by a centralized authority should be minimized; all aspects of network management should be handled in a distributed
manner, with all network elements sharing a collective responsibility of performance maintenance. Our technology
development fell into three basic areas. First, we conducted an in-depth study of phase transitions and complexity in large
wireless networks. Our goal in this area was the identification of complexity thresholds, bounding the computational
complexity of management protocols for extremely large networks. Second, we considered the use of game theory in the
development of truly distributed network control algorithms. Finally, we developed models for the trade-off between energy
conservation and robustness in wireless networks.
DTIC
Communication Networks; Configuration Management; Data Processing
20040111532 Engineering Research and Consulting, Inc., Edwards AFB, CA
Numerical Modeling of ISS Thruster Plume Induced Contamination Environment
Alexeenko, A. A.; Wadsworth, D. C.; Gimelshein, S. F.; Ketsdever, A. D.; Jul. 21, 2004; 12 pp.; In English; Original contains
color illustrations
Contract(s)/Grant(s): F04611-99-C-0025
Report No.(s): AD-A425541; No Copyright; Avail: CASI; A03, Hardcopy
Assessment of thruster induced contamination of critical surfaces is the important and necessary stage of International
Space Station (ISS) component design. Plume contamination models aimed at the prediction of the spatial distribution of
contaminant mass fluxes have been developed in the recent years for various ISS thrusters based on vacuum chamber and
space flight experiments and empirical correlations 1, 2. Relatively scarce space flight contamination data have been gathered
to date and are mostly limited to the measurements of thruster plume centerline contaminant fluxes. It is necessary, however,
to have detailed knowledge of the contaminant deposition as a function of the angle from the plume centerline, especially, in
the plume backflow region. The realization of this fact has motivated new flight experiments which are being planned for a
future Space Shuttle mission.
DTIC
Contaminants; Contamination; Exhaust Gases; Flux (Rate); Mathematical Models; Numerical Analysis; Plumes
20040111993 NASA Langley Research Center, Hampton, VA, USA
Continuous Optimization on Constraint Manifolds
Dean, Edwin B.; [1988]; 14 pp.; In English; TIMS/ORSA Joint National Meeting, 25-27 Apr. 1988, Washington, DC, USA;
Original contains black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
This paper demonstrates continuous optimization on the differentiable manifold formed by continuous constraint
functions. The first order tensor geodesic differential equation is solved on the manifold in both numerical and closed analytic
form for simple nonlinear programs. Advantages and disadvantages with respect to conventional optimization techniques are
discussed.
Author
Manifolds (Mathematics); Optimization; Constraints; Differential Equations; Functions (Mathematics); Continuity
(Mathematics)
20040120960 NASA Langley Research Center, Hampton, VA, USA
Reconfigurability in MDO Problem Synthesis, Part 1
Alexandrov, Natalia M.; Lewis, Robert Michael; [2004]; 10 pp.; In English; 10th AIAA/ISSMO Multidisciplinary Analysis
and Optimization, 30 Aug. - 1 Sep. 2004, Albany, NY, USA; Original contains color illustrations
Contract(s)/Grant(s): NCC1-02029; NSF DMS-02-15444
Report No.(s): AIAA Paper 2004-4307-Pt-1; No Copyright; Avail: CASI; A02, Hardcopy
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