lyu0101 wireless digital library on pda lam yee gordon yeung kam wah supervisor prof. michael lyu...
TRANSCRIPT
LYU0101
Wireless Digital Library on PDA
Lam Yee Gordon Yeung Kam Wah
Supervisor Prof. Michael Lyu
First semester FYP Presentation 2001~2002
Introduction Mobile Technology develop rapidly
PDA become cheaper and more powerful Wireless communication
Wireless LAN / BlueTooth 3G
Demand on Information/services increase IBM estimates market for mobile
services equals to $30.5 billion by 2003
Information related to client’s location
Search function Support multimedia content
Wireless Digital Video Library on PDA
Wireless Digital Video Library on PDA
Usage Shopping guild in a Shopping Mall Information search in an Exhibition Showing vacancy in a Car Park Digital video Library client
Pocket PC vs Palm OS as our developing Platform
Pocket PC have better support in Internet Multi-Media
Performance processing power of Pocket PC is higher
than Palm OS nowaday
Both technology can give high speed data transfer rate to mobile devices, allowing video, audio and other applications.
3G is the Third Generation standard for mobile multimedia, speed varies from 144 kbps to 2Mbps
Bluetooth provide a short-range communications standard allowing wireless data communications at ranges of about 10 meters, with low cost and low power consumption.
3G and Bluetooth
Our first application use a web base approach, which supports:
(1) Searching of key word in news report (2) Display of the main frame as the
search result (3) Have a abstracts and key frame of
each news report (4) Have a news report reading mode (5) Have Video Steaming on news report
Introduction of First Trial Application
Architecture of First Application
Pocket PCPocket IE
with Network support
CGI request and HTML reply
News content and key frames
MMS server which support video
steamming
Web Server
File ac
cess
It has low extensibility. Its functionality is limit by the
power of Pocket IE. Sequential search is used to
search the key words in the news files
Limitation in our First Application (I)
Changing in format of display for the information needs to have an overall change of Server part. Maintenance on the Application become difficult.
Playing of video need to jump out our Application, and we can’t control on the playing of it
Limitation in our First Application (II)
Use XML as the primary data format (vs. use a fixed self-defined data format)
Use XSL with XSLT as method for translation of XML data into a format for presentation (vs. use a CGI program)
Use XHTML as media for presenting the information (vs. use HTML)
Idea to overcome the limitation (I)
Storage of XML in Database (vs. storing XML as file)
Study Indexing Technique in order to have better searching performance to retrieve the information in XML (vs. sequential search in data file)
Use Embedded Visual C++ with Win32 to build our application (vs. use Pocket IE)
Idea to overcome the limitation (II)
To give our user a feasible and extensible way to design the data structure
Changing the structure of the data or adding new data structure will not affect our whole system process on the data
Use together with XSL and XSLT to generate XHTML, which can: give the user a feasible way to design Have changes on format of display will not
affect the design of our whole system
Reason of Using XML
Provide a standard and powerful way to transform from XML format data to another informative Formal
Give our user a feasible and extensible way to design the presentation of their own data
Change or define a new way to present XML data will not affect our whole system processing on it. Maintenance becomes easier
Reason of Using XSL and XSLT
Both of them can be the product after XSLT, and can be just browse on nowadays browsers.
Parsing of them will be much more efficient than man-made HTML, which is more suitable for PDA browser
Good for future development of the HTML-based browsers, as new features can be standardize by the XSL
Reason of Using XHTML and XHTML base
Database provides us many useful services, e.g. building different kinds of indexing on data, concurrency control, recoverability of data, etc.
Our application really need an database in order to have fast information retrieve
Reason of Storing XML in Database
Server XML format data store in Database Format the query result using XSL
Client Display information Send user request to server
Network TCP/IP HTTP
System Design
System Design Why using TCP/IP and HTTP
Well supported Likely supported by new wireless
technology Compatible with existing hardware
and network
Five main modules: XML manager XSL manager Search Engine Output Format manager Main Co-operator
Server Side Design
How to convert XML into Database (I)
We can treat an XML Document as a Tree
Each Tree node will be have (1) attributes, (2) child nodes
We will assign an unique ID to each Tree node
A Tree node can be (1) tag, (2) attribute’s name, (3) data (including attribute’s value)
How to convert XML into Database (II)
There will be one main schema in the Database that for store up the XML
Tree_Node= (Parent ID, NodeID, Type, Value)
Type can be (1) tag, (2) attribute, (3) data Value can be (1) tag name, (2) attribute’s n
ame, (3) attribute’s value, (4) data
Example of converting an XML document into
Database (I) A very simple XML document: <Shopping Mall>
<Shop shop_no=‘001’><name>
aShop</name>
</Shop></Shopping Mall>
ParentID
NodeID Type Value
Null 0 tag Shopping Mall
0 1 tag Shop
1 2 attribute
shop_no
2 3 data 001
1 4 tag name
4 5 data aShop
Example of converting an XML document into
Database (II) Result in Database: Table of Tree
Node
More (1) Searching (2) Modification or
(3) Deletion of a tree node and its child nodes or (4) reproduce XML in certain tree level can be done by recursive function
The NodeID is very helpful in such recursion function
XSL manager Two main functions:
Control the access of XSL program in database
remember the template of each XSL program and the depth of tree level access at that template
for Output Format manager to find a suitable XSL program to translate the XML in search result
(each XSL program have templates to state which XML’s tree node data are operated on)
Search Engine As an Information retrieve system, we n
eed to perform searching on XML Data Search Engine builds index on (1) tag,
(2) attribute‘s name and value, (3) Data
Search result will be a list of nodeID Building index and searching Techniqu
es need to have further study
Output Format manager Co-operate with XML Manager, Search Engin
e and XSL manager, through XSLT to produce final output
It will perform the following operation: get the list of nodeID of search result from the Se
arch Engine for each of nodeID, find whether there is suitable
XSL program from XSL manager for translation do post-reformatting to all the result of translati
on
Main Co-operator Three main functions:
Receive request from PDA client Co-operate with other module to
generate result pages Send out the result to PDA client
Client Side Design Pocket PC client The four main component
Control component HTML viewer Video window Image window
Client Side Design HTML viewer
Using system provided DLL Use as a interface interact with user User action messages will pass
control component Customize some HTML events for our
own use
Client Side Design Video/Audio window
Using system provide COM object Using to display video to user
Image window Using to display image Specify to display map like image Not yet implemented
Client Side Design Why using system provide components
Limited storage memory 32Mb memory to store data and programs The components is optimized
Why using HTML viewer as interface HTML is well developed Provide feasible interface design to server
Work done Study on PDA/Wireless
communication Build a trial application on Pocket
PC Design the system architecture Build the Pocket PC Client