This document discusses query processing in mobile computing environments. It begins with introductions to computing, mobility, and mobile computing. It then describes the basic phases of query processing as local processing, reduction, and final processing. It discusses join processing specifically and exploiting asymmetric features of mobile environments like differences in computing power and energy consumption between servers and mobile devices. The document proposes processing joins at servers or mobile devices and using mobile-initiated or server-initiated semijoins to improve efficiency. It concludes that considering these asymmetric features can lead to more energy-efficient and effective query processing procedures for mobile systems.

1. Query Processing in a Mobile Computing
Environment
Exploiting the features of Asymmetry
Presented By-
Nirmala Parewa
2010UCS035

2. CONTENTS
1.INTRODUCTION—
A. Computing
B. Mobile
C. Mobile Computing
2.Query Processing in mobile computing
3. Asymmetric features of mobile computing
4. Conclusion

3.  What is computing??
 Operation of computers (according to
oxfords advance learner’s dictionary).
Introduction-

4.  That someone /something can move or
be moved easily and quickly from place to
place .
What is the mobile??

5. What Is Mobile Computing??
 A simple definition could be:
Mobile Computing is using a computer (of one kind or
another) while on the move
 Another definition could be:
Mobile Computing is when a (work) process is moved from a
normal fixed position to a more dynamic position.
 Mobile Computing is an umbrella term used to describe
technologies that enable people to access network services
anyplace, anytime, and anywhere.
5

6. Why Go Mobile?
 Enable anywhere/anytime connectivity
 Enable mobility
 Enable new applications
 An exciting new research area
6

7. Applications-
In a mobile computing environment, a mobile
user with a power-limited palm computer (or a
mobile computer) can access various information
via wireless communication.
Applications include-
 stock activities
 traffic reports and
 weather forecasts

8. Query Processing in Mobile
Computing
 With the cutting edge technology advancements in wireless
and mobile computers, the query processing in a mobile
environment has become the major research area.
 A mobile database is the one which can be connected to a
mobile computing device over a mobile network. The mobile
client and the back-end database server communicate over
wireless connections. Thus enabling the access to data at
anytime and from anyplace
 The aim of this paper is to describe the basic query
processing mechanism in any database and show how data is
synchronized between the mobile and backend databases

9. Basic Query Processing Mechanism

10. The query processing in a traditional
distributed system is composed of the
following three phases:
1. local processing phase
2. reduction phase and
3. final processing phase.

11. JOIN PROCESSING IN A MOBILE
COMPUTING SYSTEM
 Processing the Join at the Server.
 Processing the Join at the Mobile Computer.
 Employing an MI /SI Profitable Semi join for
Join Processing.

12. QUERY SCENARIO OF JOIN PROCESSING
A query scenario of join processing.

13. PRELIMINARIES:
1. NOTATION , DEFINITION AND ASSUMPTION
 Query processing in a mobile environment, which
involves join processing among different sites
including static servers and mobile computers.
 A mobile computing system consists of stationary
servers and mobile computers.
 Stationary servers include information servers and
the equipment of a mobile communication system.

14. 2. COST MODEL FOR JOIN AND QUERY
PROCESSING IN A MOBILE
COMPUTING SYSTEM
 The processing time of joining Ri and Rj at a mobile
computer can be expressed by
(Ri l><l Rj).
 The amount of energy consumed in processing the
join between Ri and Rj at a mobile computer is
devised as
1/δ*(Ri l><l Rj).

15. Key Features Of Mobile Environment
There are some asymmetric features, which we shall
explicitly address and reflect in the design of query
processing schemes, are as follows:
1. Asymmetric feature of computing capability between the
server and a mobile computer:-
 The energy expended at the mobile station for sending data
on a wireless link more than energy expended when it is
receiving the amount of the data.
2. Asymmetric feature of energy consumption between
message sending and receiving-

16.  energy consumption between message sending and receiving
that’s means sending any information that how much using
energy for one request.
3. Asymmetric and idle energy of a mobile computer:-
 The energy consumed when the mobile station is actively
computing is much more than thats consumed when the mobile is
idle.

17. 4.Asymmetric in bandwidth availability and cost between
wireless and wired links.
5.Change in cost of communicating with a mobile as it
moves-two scenario considered here:
A. The first scenario deals with a mobile moving within a
cell.
B. He second scenario due to the mobile moving between
service areas.

18. Conclusion:
 Explored these asymmetric features of
a mobile environment-
 Devised query processing methods for both join and query
processing.
 Different join methods and devised some specific criteria to
identify MI/SI profitable semi joins.
 By exploiting these asymmetric features, these characteristic
functions are very powerful in reducing both the amounts of
energy consumption and data transmission incurred and can
lead to the design of an efficient and effective query
processing procedure for a mobile computing environment.

19. THANK YOU
&
???