1. by :
Shilpa Chaturvedi 07 Supriya Ghatkar 12
Nikhila Rane 22 Kshitija Raut 23
Rupali Maeen 39 Kanchana Nayakkar 41
Lekha Pedamkar 50

4.  MOBILE DATABASE : Database than can be connected to by a
mobile computing device over a mobile network.
CACHE : Hold frequent data and transactions
 DATABASE : Structured way to organize information
The use of laptops, mobiles and PDAs is increasing and likely
to increase in the future with more and more applications
residing in the mobile systems.
 example : MOBILE WORKFORCE.
In this scenario user would require to access and
update information from files in the home directories on a
server or customer records from a database. With the advent
of mobile databases users can load up their smart phones or
PDAs with mobile databases to exchange data remotely
without worrying about time or distance.
 Mobile databases let employees enter data on the fly.

5.  Mobile users must be able to work without a wireless
connection due to poor or even non-existent connections.
 Applications must provide significant interactivity .
 Applications must be able to access local device/vehicle
hardware, such as
printers, bar code scanners, or GPS units (for mapping or Automatic
Vehicle
Location systems).
 Bandwidth must be conserved (a common requirement on
wireless networks that charge per megabyte or data transferred).
 Users don't require access to truly live data, only
recently modified data.

7. Functionality required oF mobile dbmS includeS ability to:
communicate with centralized database server
through modes
replicate data on centralized database server and
mobile device;
synchronize data on centralized database server and
mobile device;
capture data from various sources such as
Internet;
manage/analyze data on the mobile device;
create customized mobile applications.

8. A mobile computing environment consists of :
• mobile computers (mobile hosts)
• a wired network of computers(mobile support
stations)
Mobile host may be able to communicate with wired
network through
a wireless digital communication network
Network Infrastructure for mobile computing consists of two
technologies :
• Wireless local-area networks (within a building)
E.g. Avaya’s Orinico Wireless LAN
2. packet-based cellular telephony networks
early cellular system-Analog Technology
2G – voice application
3G and 2.5 G –Packet Based network

9. PDA
M O B IL E H O S T
W IR E L E S S L A N C E L L
2Kbps - 15M bps
BASE
S T A T IO N
F IX E D
BASE HOST
W IR E L E S S R A D IO C E L L S T A T IO N
9Kbps - 14Kbps
F IX E D N E T W O R K
BASE
S T A T IO N
M b p s to G b p s
BASE
S T A T IO N
PDA

10. A model for mobile communication
Mobile hosts communicate to the wired network via
computers referred to as mobile support (or base) stations.
Each mobile support station manages those mobile
hosts within its cell.
When mobile hosts move between cells, there is a
handoff of control from one mobile support station to
another.
Direct communication, without going through
a mobile support station is also possible between
nearby mobile hosts
Supported, for e.g., by the Bluetooth standard
(up to 10 meters, at up to 721 kbps)

11. New issues for query optimization.
• Connection time charges and number of bytes
transmitted
• Energy (battery power) is a scarce resource and its
usage must be
minimized
Mobile user’s locations may be a parameter of the
query
•GIS (Geographic Information Systems )queries
• Techniques to track locations of large numbers of
mobile hosts
 Broadcast data can enable any number of clients to
receive the same data at
no extra cost leads to interesting querying and data
caching issues.
 Users may need to be able to perform database
updates even while the

12. Must consider these competing costs:
User time
Communication cost
• Connection time - used to assign monetary charges in
some cellular
systems.
•Number of bytes, or packets, transferred - used to compute
charges in digital cellular systems
•Time-of-day based charges - vary based on peak or off-
peak periods
Energy - optimize use of battery power by minimizing
reception and transmission of data.
 Receiving radio signals requires much less energy
than transmitting
radio signals.

13. • Mobile support stations can broadcast frequently-
requested
data
• Allows mobile hosts to wait for needed data, rather
than having to
consume energy
There are two reasons for using broadcast data.
= the mobile host avoids the energy cost for
transmitting data requests
= the broadcast data can be received by a
large number of mobile hosts at once,
at no extra cost
The mobile host can cache the broadcast data
For later use.

14.  Broadcast data may be transmitted according to a fixed
schedule
or a changeable schedule:
FIXED SCHEDULE: The mobile host uses the known
fixed
schedule to determine when the relevant data
will be
transmitted.
 CHANGEABLE SCHEDULE: The broadcast schedule
must itself
be broadcast at a well-known radio frequency
and at
well-known time intervals.
 The need for Data Broadcast:
Data should be organized and presented to the users
based on its need.

15.  Problems created if the user of the mobile
host issues
queries and updates on data that resides
or is cached
locally:
 This situation creates several problems, in
particular:
•RECOVERABILITY: Updates entered on a
disconnected machine may be
lost if the
mobile host fails.
•CONSISTENCY : Cached data may become
out of date,

16.  Partitioning via disconnection is the normal mode of operation
in mobile
computing.
 For data updated by only one mobile host, it is simple to
propagate update when
mobile host reconnects n other cases data may become
invalid and updates may
conflict.
 When data are updated by other computers, invalidation
reports inform a
reconnected mobile host of out-of-date cache entries
however, mobile host may miss a report.
VERSION-NUMBERING-based schemes
guarantee only that if two hosts
independently update the same version of a
document, the clash will be detected
eventually, when the hosts exchange

17. • BUSINESS TRAVELERS : use laptop computers so that
they can work and access data en route
• DELIVERY SERVICES : uses it for packet tracking
• EMERGENCY RESPONSE : uses it at the scene of
disasters ,medical emergencies ,and the like to access
information and to enter data pertaining to the situation
• CELL PHONES : provide not only phone
services but are also mobile computers
allowing email and web access