NASA Scientific and Technical Aerospace Reports

formulation in terms of distributed constraint optimization and developed a simple anytime algorithm that was shown to be
effective efficient robust and scalable to large problems. It extended the formulation and algorithm to the management of
distributed sensors in a target detection and tracking application. It also developed high-level models for resource management
in time-critical targeting in air campaigns and extended an existing scheduler generator tool to automatically generate
executable schedulers that quickly assign aircraft and munitions to prosecute targets of opportunity while minimizing
disruption to pre-planned target prosecutions.
DTIC
Algorithms; Autonomy; Real Time Operation; Synthesizers
20040111536 Georgia Tech Research Inst., Atlanta, GA
Super-Resolution Still and Video Reconstruction from MPEG Coded Video
Altunbasak, Yucel; May 31, 2004; 88 pp.; In English; Original contains color illustrations
Contract(s)/Grant(s): N00014-01-1-0619
Report No.(s): AD-A425551; E-21-H52; No Copyright; Avail: CASI; A05, Hardcopy
Transform coding is a popular and effective compression method for both still images and video sequences, as is evident
from its widespread use in international media coding standards such as MPEG, H.263 and JPEG. The motion- compensated
image (or the image itself) is divided into blocks and each block is independently transformed by a 2-D orthogonal transform
to achieve energy compaction. The most commonly used transform is the discrete cosine transform (DCT). After the block
transform, the transform coefficients undergo a quantization step. At low bit-rates, the DCT coefficients are coarsely quantized.
This coarse quantization with independent quantization of neighboring blocks gives rise to blocking artifacts visible block
boundaries.
DTIC
Coding; Discrete Functions; Fourier Transformation
20040111545 Boston Univ., Boston, MA
Causality Constraints on the Analysis and Active Control of Structures
McDaniel, J. G.; Clarke, Cory L.; Li, Xianhui; Zhao, Xianfeng; Jul. 26, 2004; 76 pp.; In English
Contract(s)/Grant(s): N00014-99-1-1017
Report No.(s): AD-A425573; No Copyright; Avail: CASI; A05, Hardcopy
This research has integrated the causality condition into frequency-domain analysis and control of structural vibration,
acoustic scattering, and acoustic radiation. As a result of these efforts, a variety of active and passive control approaches are
now physically realizable. In the time domain, causality simply requires that a system’s response cannot precede its cause. In
active control problems, the causality condition further requires that one cannot use future disturbance information to
determine control actuation. These conditions are more subtle in the frequency domain, where one typically interprets
experimental data and constructs active and passive control approaches. In the frequency domain, the causality condition
assumes the form of Hilbert transform relations between elements of the complex Fourier transform of a causal response. This
research produced analytical formulations of the causality condition to enhance experimental data and to devise physically
realizable control approaches in the frequency domain. Two contemporary active control approaches were used to illustrate
the inclusion of causality. The research developed such formulations, and their algorithmic implementations, with a close
association to experimental data and control approaches that are of contemporary importance to the Office of Naval Research.
DTIC
Active Control; Structural Analysis
20040111968 NASA Langley Research Center, Hampton, VA, USA
Dynamic Eigenvalue/Eigenvector Tracking Using Continuous Optimization on Constraint Manifolds
Dean, Edwin B.; [1988]; 11 pp.; In English; TIMS/ORSA Joint National Meeting, 24-26 Oct. 1988, Denver, CO, USA;
Original contains black and white illustrations; No Copyright; Avail: CASI; A03, Hardcopy
This paper demonstrates the capability to obtain and dynamically track eigenvalues and eigenvectors using continuous
optimization on constraint manifolds.
Author
Eigenvalues; Eigenvectors; Optimization; Constraints; Manifolds (Mathematics)
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