SNS COLLEGE OF ENGINEERING
Kurumbapalayam(Po), Coimbatore – 641 107
Accredited by NAAC-UGC with ‘A’ Grade
Approved by AICTE & Affiliated to Anna University, Chennai
INTERNAL ASSESMENT EXAMINATIONS – III
COURSE: B.E – CSE
CS2402 – MOBILE AND PERVASIVE COMPUTING
Class: VII Sem CSE
Duration: 2 Hours
ANSWER KEY
Maximum: 50 Marks
PART A - (10 X 2 = 20 marks)
1. Mention the goal of M-TCP?
2.
3.
4.
5.
6.
Splits TCP connection, chokes sender via window size.
What led to the development of Indirect TCP?
The TCP connection between the mobile host (MH) and the correspondent host (CH) is
split at the mobility support router (MSR). The connection between the MSR and MH has
independent, optimized flow and congestion control from the MSR to CH link. In fact, a
separate transport protocol can be used.
Mention the primary goal of WAP.
WAP's goal is to allow a wide variety of wireless devices to access live information
resources and applications. The philosophy behind WAP's approach is to utilize as few
resources as possible on the handheld device and compensate for the constraints of the device
by enriching the functionality of the network.
Mention the features present in WSP/B in addition to that present in WSP.
1. HTTP/1.1 functionality
2. Exchange of session headers
3. Push and Pull Data transfer
4. Asynchronous requests
What are the basic features of WML?
 WML is a markup language for small, wireless computing devices.
 In WML, variables can be defined that store data in string format. In HTML, variables
cannot be stored.
 WML uses WML script for client-side scripting, which is stored in a separate file. HTML
uses JavaScript.
 The supported image format for WML is WBMP. HTML supports JPEG, GIF and BMP.
 A micro-browser is used to run WML markup. A regular browser, such as Internet
Explorer, Firefox or Chrome, is used to run HTML markup.
 WML follows XHTML specification and is therefore case sensitive. HTML is not case
sensitive.
 WML has fewer tags compared to HTML.
 A deck is a set of WML cards. In HTML, a site is a set of HTML pages.
What are the three ways of WTA extends the WAE application model?

Content push: A WTA origin server can push the content.

Handling of network events: A device can have a table indicating how to react to
certain events from the mobile network.

Access to telephony function: Application running on the client can access telephony
functions from WML or WML script is very simple.
7. Aim of pervasive computing? Is it different from ubiquitous computing?
Pervasive computing (also called ubiquitous computing) is the growing trend towards
embedding microprocessors in everyday objects so they can communicate information. The
words pervasive and ubiquitous mean "existing everywhere." Pervasive computing devices
are completely connected and constantly available.
8. Why is palm OS popular in PDA’s?
Palm OS is a mobile operating system initially developed by Palm, Inc., for personal
digital assistants (PDAs) in 1996. Palm OS is designed for ease of use with a touch screenbased graphical user interface. It is provided with a suite of basic applications for personal
information management. Later versions of the OS have been extended to support smart
phones. Several other licensees have manufactured devices powered by Palm OS.
9. List the characteristics of smart card.
 Dimensions similar to those of a credit card. ID-1 of the ISO/IEC 7810 standard defines
cards as nominally 85.60 by 53.98 millimetres (3.370 in × 2.125 in). Another popular size
is ID-000 which is nominally 25 by 15 millimetres (0.984 in × 0.591 in) (commonly used
in SIM cards). Both are 0.76 millimetres (0.030 in) thick.
 Contains a tamper-resistant security system (for example a secure cryptoprocessor and a
secure file system) and provides security services (e.g., protects in-memory information).
 Managed by an administration system which securely interchanges information and
configuration settings with the card, controlling card blacklisting and application-data
updates.
 Communicates with external services via card-reading devices, such as ticket
readers, ATMs, DIP reader, etc.
10. How does the biometric authentication work in pervasive computing?
Biometrics is the science and technology of measuring and analyzing biological data.
It is used to uniquely identify individuals by their physical characteristics or personal behavior
traits. It is used to allow employees access to certain areas and for general ID purposes. A
biometrics system goes through three basic steps.
1.
Acquiring data
2.
Encryption
3.
Analysis of data
PART B
Answer All (5qns x 16mks = 80mks)
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a)
What are the various flavours of TCP available? Explain in detail.
1.Indirect TCP
2.Snooping TCP
3.Mobile TCP
 Fast retransmit / Fast Recovery
 Transmission / Time out Freezing
 Selective Retransmission
 Transaction oriented TCP
OR
b) (i) State the requirements of WAP. Explain its architecture components.
Requirements :
•
Leverage existing standards whenever possible
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•
•
•
•
•
Define a layered, scalable and extensible architecture
Support as many wireless networks as possible
Optimize for narrow-band bearers with high latency
Optimize for efficient use of device resources
Provide support for secure applications and communication
(ii) Explain WAE architecture.
• General-purpose application environment based on a combination of WWW and
mobile telephony technologies.
• It defines the user interface on the phone. It contains WML and WTA (Wireless
Telephony Application).
• Primary objective – interoperable environment.
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a)
Explain the following
(i)Wireless datagram protocol
• The WAP datagram protocol (WDP) is the Transport layer that sends and
receives messages via any available bearer network, including SMS, USSD,
CSD, CDPD, IS–136 packet data, and GPRS.
• Operates above the data capable bearer services supported by various network
types.
• Provides a common unction independent of the underlying wireless network
interface to the upper layer protocols and hence they fork.
(ii) Wireless transport layer security
Based on industry-standard Transport Layer Security (TLS) protocol
• Optimized for use over narrow-band communication channels
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•
Features:
– Data integrity
– Privacy
– Authentication
--Denial-of-service protection
OR
b) Explain the following
(i)Wireless transaction protocol
• The WAP transaction protocol (WTP) layer provides transaction support, adding
reliability to the datagram service provided by WDP.
• Light weight transaction-oriented protocol
• Three classes of transaction services
– Unreliable one-way requests
– Reliable one-way requests
– Reliable two-way request-reply transactions
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a)
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(ii) Wireless session protocol
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• The WAP session protocol (WSP) layer provides a lightweight session layer to
allow efficient exchange of data between applications.
• Application layer with a consistent interface for two session services
– Connection-oriented service that operates above the transaction
layer protocol (WTP)
– Connectionless service that operates above a secure or non-secure
datagram service (WDP)
– Optimized for low-bandwidth bearer networks with long latency
(i) What is WML? Explain deck and card with WML code.
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WML is the worldwide industry standard.
 WML is a markup language for small, wireless computing devices.
 In WML, variables can be defined that store data in string format. In HTML,
variables cannot be stored.
 WML uses WML script for client-side scripting, which is stored in a separate
file. HTML uses JavaScript.
 The supported image format for WML is WBMP. HTML supports JPEG, GIF
and BMP.
 A micro-browser is used to run WML markup. A regular browser, such as
Internet Explorer, Firefox or Chrome, is used to run HTML markup.
 WML follows XHTML specification and is therefore case sensitive. HTML is
not case sensitive.
 WML has fewer tags compared to HTML.
 A deck is a set of WML cards. In HTML, a site is a set of HTML pages.
DECKS and Cards :
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN"
"http://www.wapforum.org/DTD/wml12.dtd">
<wml>
<card id="one" title="First Card">
<p>
This is the first card in the deck
</p>
</card>
<card id="two" title="Second Card">
<p>
Ths is the second card in the deck
</p>
</card>
</wml>
(ii) What are the design and implementation issues in device connectivity aspect of
pervasive computing? Explain.
1. The protocol for device to device to server interactions that are relevant in the
pervasive computing domain
2. The algorithm and protocols to address the security issue
Protocols:
The protocols are needed when a device wants to exchange data with other devices. E.G
Wireless Protocols
The yet another important topic is the consistency of the databases and their data
between a server and pervasive computing devices. The consistency can be solved by
synchronization or replication.
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OR
b) Explain the operating system issues related to miniature devices.
 Separation of concerns
 Components
 Real world Interfacing
 Frameworks
 Multi Dimensional Optimization
 Hardware / Software Co –Design
Networking of miniature devices
a) Describe the various hardware components involved in pervasive computing devices.
 Batteries
 Nickel cadmium cell
 Lithium polymer battery
 Display
 DSTN
 OLED
 Memory
OR
b) What are the applications of pervasive computing? Discuss any two of them.
 Retail
 Airline check in and booking
 Sales force automation
 Health care
 Tracking
 Car information system
 Email access via WAP and voice

a) Explain how pervasive web applications can be accessed via WAP.
WAP Functionality:
Simple interactions with the services the internet can be done using a WAP device.
Infrastructure
A WAP gateway sits between mobile devices using the WAP protocol and the World
Wide Web, passing pages from one to the other much like a proxy.
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This translates pages into a form suitable for the mobiles, for instance using the
Wireless Markup Language (WML).
OR
b) (i) Explain the various soft surface and semi-soft-surface-based display system and
technologies.
 Hardware Technology
 Software Technology
 Operating System and Java Platform
Hardware Technology
Batteries
Nickel Cadmium Cell
Nickel metal hydride
Lithium battery
Displays
LCO are replacing CRT used in the part
 DSTN
 OLED – Light emitting Organic Diode
 LEP - Light Emitting Polymer Technologies
(ii) Explain how a pervasive web application can be secured using an ‘Authentication
Proxy’.
The application uses a ID and a numerical password for authentication. This has the
advantage because it can work on any time.
Reliability
Trust
Data access
Malicious attacks
Information propagation
Customer ID using MISISDN Numbers
Customer authentication using WIM
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