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