Aerospace Information Server
This research activity establishes an Aerospace
Information Server to collect, manage, and analyze aerospace information
in different categories with different formats, and make it available
to the aerospace community and the general public. The following points
of interest are the focus of this research activity:
• Telescope
imagery;
• Decentralized
control signals for precision pointing of the telescope;
• Telescope
animation for distance control; and
• Visualization
for flight dynamics and control, among other matters.
The server is designed to be accessible
through the Internet or other special-purpose networks to support
interactive query, scalable image browsing, and on-line simulation.
One example of the basic structure of the server is depicted in Figure
1. Note that different levels of accessibility may be permitted to
users with different authorities.
Interactive query is a basic function for
any information system, but creating an efficient query is particularly
challenging in a multimedia database. To improve the accuracy and
efficiency of query, this research activity employs advanced data-mining
technology in the Aerospace Information Server. In order to disseminate
the rich multimedia content in the information server, representative
features of images or video frames can be extracted and stored in
the database. The system incorporates the Gabor function in the feature
extraction mechanism, as it can be used to model the response of simple
cells in visual cortex, and fast-searching algorithms are designed
to speed up the on-line query.
In addition to interactive query, the proposed
information server is designed to support a novel scenario for scalable
browsing. Most current information systems/databases on the Internet
implement scalable browsing by storing multiple versions of images
of different resolutions or quality. Problems associated with this
browsing scheme include inefficient storage and lack of bandwidth
adaptivity. Using scalable compression technologies, the Investigators
can solve this problem. In the proposed scheme, only one version of
a compressed image is stored on the server. Using progressive coding/decoding,
the compressed image video can be decoded at any bit rate to support
arbitrary quality requirements. The Investigators design an adaptive
rate control module to work with the scalable compression to allocate
bandwidth dynamically according to the users' requirements and traffic
conditions. This browsing scheme is able to meet different Quality
of Services (QoS) requirements in a heterogeneous network, as illustrated
by Figure 2. It can also improve the bandwidth utility throughout
the system.
Rich functionality is another advantage
of the proposed Aerospace Information Server. Unlike the current aerospace
database, the information server is able to analyze and process stored
data and images for research and education purposes. For example,
the Investigators use on-line image processing tools to analyze the
astronomical images, and incorporate astrophysical models to develop
a simulation toolbox for the convenience of aerospace research or
teaching. Key technologies involved include: High-performance computation,
multimedia database design, data-mining technologies including classification
and feature extraction, content-based query (object-tracking), multi-resolution
image display, and real-time streaming to distribute the stored images
to multiple users.
Figure 1 - Aerospace Information Server Flowchart
 Figure 2 - Server Overview
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