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Student Assistants:
Sergio BeltranAlexander AlegreJorge EstradaAleksander Milshteyn
S P A C ES P A C EStructures, Propulsion, And Control EngineeringStructures, Propulsion, And Control Engineering
C e n t e rC e n t e r
NASA Grant URC NCC NASA Grant URC NCC NNX08BA44AAugust 20, 2009August 20, 2009
Computer Team Progress Report
Faculty Advisors:
Dr. Helen Boussalis - DirectorDr. Charles Liu - Assistant Director
Distributed tuple space system Utilizes the capabilities of different serving
computers at various processing levels
Screen-scraping utility “Computer-friendly” tagging system
Development of video conferencing software
Server Hierarchy
Objectives
Current Tuple Architecture
Ubiquitous Aerospace Server
Screen Scraping
Ubiquitous Video Conferencing
Conclusion
Supports One Server
Multiple Clients
Multiple Workers
One Database
Not Platform Independent
Supports Multiple Server
Supports Multiple Clients
Transparent to the Client
Fault tolerant Capability
Listing of information which provides details about an object. For our case Semantic Web Objects.
Example Phone Book Domain Controller
A specialized database that stores typed and ordered information about objects
Directories allow users or applications to find resources that have the characteristics needed for a particular task.
Will hold information pertaining to objects in the Database
For Example Files Objects ( images, text excerpts, …) Semantic Tagged objects Location of data
Semantic Web
Text editing Capability
Scrape data from Web Browser
Image scrapping or cut and paste
Capability to upload and Download from a Server
Ability to modify an create new Tags
Written in Java (Platform Independent)
Ubiquitous Video Conferencing
Ubicomp - Human-computer interaction that goes beyond desktop environment and is used in everyday life
Video Conferencing – Visual collaboration between two or more locations. Transmits audio and video information cohesively in a real time, over the specified network.
Ubiquitous Computing Video Conferencing Ubiquitous
Computing
Objectives
Server ConfigurationVideo Encoding SelectionBandwidthSecurityUDP
Ring ConfigurationPeer-to-Peer ConfigurationHybrid Configuration (globally decentralized, locally
centralized)
•Node connects EXACTLY to two other nodes• Data travels from node to node• Single failure in any node will disrupt the whole network, making it unreliable
Distributed Network Architecture Formed by Ad-hoc, addition of nodes Not ideal for ubiquitous videoconferencing (E.G. Multiple connections)
Globally decentralized, locally centralized
Model without handshaking
- dropping packets
preferable of delayed packets
- error checking is not necessary
- widely used in multicasting
http://en.wikipedia.org/wiki/User_Datagram_Protocol
- Use datagram sockets to establish host to host communication
- Sockets bind the application to service ports, that function as the endpoints of data transmission
- Ports from 30,000 through 65,535 - used as temporary ports by clients connecting to servers
Server
C1TP: [40000] C2
RP: [40000]
C4RP: [40000]
RP: 30000
RP: 50000
RP: 60000
Proposed Hybrid Setup
Infinite amount of nodes (cameras) on a distributed video server
Proposed Hybrid Setup
Infinite amount of nodes (cameras) on a distributed video server
Previous Setup
Three nodes connected to the one centralized Internet server
Intra-Group Connection
Four nodes connected to one centralized SPACE Center Video server, including one user from a different network.
Motion JPEG- Encodes similarly to MPEG-1,
MPEG-2- Maximum compression rate –
1:20- Low computational complexity- Low group delay
MPEG-4- Encodes mixed media-data
(video/audio)- Real world compression – 1:50- Transforms into other types of
signals - Scalable to deliver content at any
data rate
Proposed Settings: - 50 text-only users - 5 to 16 video users(determined by bandwidth/memory calculations and real-time
testing) Existing programs - Skype: 50 text-only users, 5 video users - MegaMeeting: text-only users, 16 video
users
Channel delivers at a lower rate than its nominal transmission rate
CL = Capacity of channel HL = Total layer-2 overheadPL = Packet size CL2 = New capacity
Example: For a 10BaseT Ethernet, CL = 10Mps, HL = 18bytes and a 100-byte packets the capacity is 7.24Mbps
Calculating server bandwidth(BWs):BWs = (P × N) × SP = number of sendersN = number of receiversS = average stream bit-rate of encoded A/V content
Calculating client bandwidth needs (BWc):BWc = P × SP = number of sendersS = average stream bit rate of encoded A/V content
Reserve about 20% of Client’s bandwidth for other simultaneous applications during videoconferencing
- email, internet browser, other downloading
Upload speed varies from download speed on different networks
User Adjustments:1)Lower Resolution2)Video Window Resizing3)Close video portion. Keep audio/text intact
Automatic Adjustment:1)Change compression algorithms based on
the need E.G. MPEG-4 Motion JPEG
Intra-group: requires each member of the group to have user name and valid password
Inter-group: Administrators of two or more groups established connection with each other, allow their members to see every client involved
User who has a simultaneous access to more than one group will NOT be able to distribute the video/audio/text data between members of different groups
Set-up and integrate server communication with real-time video transmission
Integrate security protocols (SSL)
Development of screen-scraping and hierarchical protocol structures
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