NASA Scientific and Technical Aerospace Reports

20060002295 Pennsylvania State Univ., University Park, PA, USA
Beaming Bandwidth via Laser Communications
Kavehrad, Mohsen; Hamzeh, Belal; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance
(ICNS) Conference and Workshop; November 2005; 33 pp.; In English; See also 20060002231; Original contains color
illustrations
Contract(s)/Grant(s): FA8650-04-C-7114; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM
only as part of the entire parent document
Fractal modulation has been traditionally investigated for use in wireless radio frequency applications, and shown to be
beneficial in fading channels and multi-rate environments. Additionally, recent research with ultra-short pulses has shown that
such signals are more resilient to water clouds and that they are transmitted through water clouds having an optical thickness
as high as 3.2 (values typical of cumulus or stratocumulus clouds) using a modest laser energy of 7 mJ/pulse and 120 fs pulse
duration. In this paper, we present a novel design for an FSO system that harnesses the merits of both fractal modulation and
ultra-short laser pulse transmissions.
Author
Bandwidth; Radio Frequencies; Pulse Duration; Optical Thickness; Optical Communication; Pulsed Lasers; Fading
20060002298 Mitre Corp., USA
Interference Cancellation Receiver
Nguyen, Minh A.; Zaghloul, Amir I.; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance
(ICNS) Conference and Workshop; November 2005; 22 pp.; In English; See also 20060002231; Original contains color
illustrations
Contract(s)/Grant(s): DTFA01-01-C-00001; No Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM
only as part of the entire parent document
Co-channel interference caused by signal collisions in systems such as slotted TDMA, Aloha, and CSMA limit the
communication system capacity and reduce the efficient use of spectrum. Therefore, it is desired that multiple corrupted
signals in the collisions be recovered. However, today s radios cannot perform this function. In this paper, we present an
interference cancellation technique that allows for the decoding of multiple co-channel signals at a small cost in performance.
The study is conducted using a BPSK modulation and demodulation method.
Author
Receivers; Radio Equipment; Electromagnetic Interference; Carrier Sense Multiple Access; Demodulation; Time Division
Multiple Access
20060002401 Massachusetts Univ., Amherst, MA USA
On Multi-Scale Differential Features for Face Recognition
Ravela, S.; Hanson, Allen R.; Jan. 1, 2005; 9 pp.; In English; Original contains color illustrations
Contract(s)/Grant(s): F19628-95-C-0235; EEC-9209623
Report No.(s): AD-A440240; No Copyright; Avail.: Defense Technical Information Center (DTIC)
This paper describes an algorithm that uses multi-scale Gaussian differential features (MGDFs) for face recognition.
Results on standard sets indicate at least 96% recognition accuracy, and a comparable or better performance with other well
known techniques. The MGDF based technique is very general; its original application included similarity retrieval in textures,
trademarks, binary shapes and heterogeneous gray-level collections.
DTIC
Electronic Equipment; Pattern Recognition
20060002479 Lawrence Livermore National Lab., Livermore, CA USA
Design and Performance Evaluation of a Coarse/Fine Precision Motion Control System
Yang, H.; Buice, E. S.; Smith, S. T.; Hocken, R. J.; Fagan, T. J.; Mar. 03, 2005; 10 pp.; In English
Report No.(s): DE2005-15016430; UCRL-PROC-210173; No Copyright; Avail.: National Technical Information Service
(NTIS)
This abstract presents current collaborative work on the development of a stage system for accurate nanometer level
positioning for scanning specimens spanning an area of 50 mm OE 50 mm. The completed system employs a coarse/fine
approach which comprises a short-range, six degree-of-freedom fine-motion platform (5 microns 200 micro-radians) carried
by a long-range, two-axis X-Y coarse positioning system. Relative motion of the stage to a fixed metrology frame will be
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