pervasive computing unit i part a -...

M.SARAVANA KARTHIKEYAN

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PERVASIVE COMPUTING

Unit I

Part A 1. What is pervasive computing?

Pervasive Computing is a technology that pervades the users‟ environment by making use of

multiple independent information devices (both fixed and mobile, homogeneous or heterogeneous)

interconnected seamlessly through wireless or wired computer communication networks which are

aimed to provide a class of computing / sensory / communication services to a class of users, preferably

transparently and can provide personalized services while ensuring a fair degree of privacy / non-

intrusiveness.

Pervasive computing integrates computation into the environment, rather than having computers

which are distinct objects. Pervasive computing is the trend towards increasingly ubiquitous an

information environment in which users have access to ICTs throughout the environment. This trend is

particularly associated with the growth of wireless technologies that allow users to access online

information and services remotely and synchronize data between different computers.

2. State Moore’s law

Moore’s law states that, ―For every 18 months, the number of transistors in an integrated electronic

circuit gets doubled with increased performance and without any increase in size‖.

3. What are the principles of pervasive computing?

Decentralization

Diversification

Connectivity

Simplicity

4. What are the basic aspects or of a Pervasive Computing environment?

Multiple devices like car key, mobile phones, car audio system, and navigation system

are integrated in the system.

A large number of different interfaces are used to build an optimized user interface.

There is a concurrent operation of offline, and temporary online systems.

A large number of specialized computer systems are interconnected via local buses and

the internet.

Short range and wide area wireless communication are integrated.

Security element provide unauthorized access.

5. List the characteristics of a Pervasive Computing?

Privacy & Security

Effectiveness of Approach Across Networks

Economic considerations

Quality considerations

Monitoring mechanisms

Adaptability and Flexibility

Practicability

Sustainability


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6. List the characteristics of a pervasive computing environment

Minimal user distraction

Collaborative interaction

User mobility

Context awareness (user/time/location)

Resource and location discovery

Ambient information, calm technology

Event notification

Adaptive interfaces

Invisibility—everyday object augmentation

Anytime/anywhere

7. Define ubiquitous computing.

Mark D.Weiser defined ubiquitous computing as ,―The most profound technologies are those

that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable

from it‖.

This invisible computing is accomplished by means of "embodied virtuality," the process of drawing

computers into the physical world which in turn made computing, omnipresent and appears everywhere

all the time.

8. List the issues involved in pervasive computing technology?

Feature-specific issues

Form-factor-(size)-specific issues

Power-provisioning issues

Weight-specific issues

Shape-specific issues

Cooling-specific issues

Connectivity-specific issues

User Interface-specific issues

Body-safety-specific issues <not for all devices>

Security-specific issues

Processor-choice-specific issues

Operating System-specific issues

Development and execution-environment-specific issues

Cost-specific issues

9. What are the hardware Device Technology for Pervasive Computing?

Power-provisioning technologies

Display technologies

Memory technologies

Communication technologies

Processor technologies

Interfacing technologies

Sensor Technologies

Authentication Technologies


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10. Define Low-power Device Technologies?

Technology that supports device performance with optimized resources in all aspects is said to

be low power device technology. As many of the devices involved in the pervasive computing

environment may have to be small in size and may have to live on their battery / power units,

consumption of lower power, extension of power provisioning period etc. assume critical significance.

In addition, prevention from excessive heating also requires attention. Power requirements can be

reduced by several means right from material selection and chip-level designing to software designing

and communication system designing. Power provisioning technology including the Battery design

technology plays a very important role in the process.

11. List the major display device technologies in pervasive computing?

Cathode Ray Tube based Displays (CRTs)

Liquid Crystal Displays (LCDs)

Active Matrix Displays

Thin Film Transistor Displays (TFTs)

Passive Matrix displays

Single Scan Displays (Colour Super-Twist Nematic: CSTNs)

Dual Scan Displays (Dual Super-Twist Nematic: DSTN)

High-Performance Addressing displays (HPAs)

Light Emitting Diode based Displays (LEDs)

Organic LED based Displays (OLEDs)

Light-Emitting Polymer based Displays (LEPs)

Chip-on-Glass Displays (CoGs)

Liquid Crystal on Glass Displays (LCoGs)

12. What are all the major hardware components considered while designing a pervasive device?

The pervasive computing devices are needed to be small, less power consuming, highly human

interacted. So the following the components are targeted..

Battery (Nickel Cadmium,Nickel Metal Hydride,Lithium-ion)

Displays (CRT,LCD,LED,OLED,CoG,LCoG)

Memory (SRAM,DRAMUt-RAM,MRAM,FRAM)

Processors (Intel SpeedStep Technology,Crusoe processor)

13. What is the latest technology emerged in batteries?

The latest in battery technology is the emergence of lithium polymer cells, which use a gel

material for the electrolyte. The batteries are made from a few thin and flexible layers, and do

not require a leak-proof casing. This means the batteries can be made in any shape or size.

14. Define Crusoe processor.

The Crusoe processor consists mostly of software. The relatively small processor is designed as a

128-bit very long instruction word processor capable of executing up to four operations per cycle.


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15. List the human machine interfaces associated with mobile and pervasive computing devices.

Navigation keys

Haptic interfaces

Keyboards

Handwriting recognition

Speech recognition

Touch screen technology

16. What do you mean by ―Fitaly‖?

The fitaly keyboard arranges the letters based on their individual frequency and the probability of

transitions in the English language. The name is derived from the orders of letters in one of the top rows

of the layout, just as the QWERTY layout.

17. What is an Octave?.

Another approach to enter a text without real or on-screen keyboard is used by octave from e-

acute. Octave maps each letter of the alphabet to one of eight unique strokes. The strokes are based on a

common characteristics part of the letters they represent and are located around the tips of a star shaped

pattern.

18. What is meant by Bio-Metrics?

Biometrics is the science and technology of measuring and analyzing biological data. In

information technology, biometrics refers to technologies that measure and analyze human body

characteristics, such as DNA, fingerprints, eye retinas and irises, voice patterns, facial patterns

and hand measurements, for authentication purposes.

19. List the operating systems available for mobile computing devices like PDA, other embedded

systems.

Palm OS

EPOC OS

WINDOWS CE OS

QNX NEUTRINO

BeOS

EMBEDDED LINUX

20. What is PALM OS?

Palm OS is the computer operating system that provides a software platform for the Palm

series of handheld personal digital assistants (PDAs) made by Palm Inc. According to Palm,

Palm OS was designed from the beginning to fit into a palm-size device of a specific size and

with a specific display size.

21. Explain briefly about BE OS.

BeOS is a powerful OS designed primarily for Multimedia desktop use. Originally BeOS

was designed for a custom computer system known as the BeBox that had special multimedia

input/output features, and was later ported to the Macintosh, and finally ported to the PC.

22. What are all the device characteristics which require J2me?

Small amount of available memory (128-512kb)

Limited energy (battery operated)


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Connected to a network

Restricted graphical display capabilities

23. List the configuration and technologies available for pervasive devices based on J2me?

Connected device configuration

Connected , Limited device configuration

Embedded Java

Java card

Real time java

24. Define Roaming Environment?

Roaming Environment: An environment that allows connectivity and communication to

the services outside the home zone is called a Roaming Environment. Some sample devices that

may involve Roaming-based access <fixed / mobile roaming>:

PDAs / Palmtops / Pocket PCs / Cell phones / Smart phones / WAP phones

Laptops / Tablet PCs / Notebook PCs

Desktop PCs / Servers / Web TVs

Kiosks

Invisible computing devices / Smart interactive posters

Wearable computers

25. What are the components of pervasive computing?

Components of Infrastructure for Pervasive Computing include Mobile computing

devices, Fixed computing devices, Multimode RF Mobile communication infrastructure <Fixed-

to- Mobile and Mobile-to- Fixed communication system interfaces>, Trust system (security and

privacy), Protocol stacks and Personalized service frameworks.

26. How does mobile internet protocol overcome the address problems of IPv4?

To overcome the address problems of IPv4 for mobile nodes mobile IP uses two IP

addresses: a fixed home address and care of address that changes at each new point of

attachment.

27. What are three steps involved in the process of Synchronization?

Pre synchronization: Prepare for actual synchronization, i.e. authentication,

authorization ,determination of device characteristics

Synchronization: Local IDs are mapped to Global IDs, and data are exchanged.

Post synchronization: Clean up tasks are performed, update the mapping tables.

28. List the characteristics of IrDA.

Frequency band

Security

Transmitting capabilities

Bandwidth

Speech


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29. List the basic security concepts involved in pervasive computing applications.

Identification

Authentication

Authorization

Transaction authorization

Digital signature endorsed by password

Transaction authentication number

Non repudiation

30. List the Challenges of device management in Pervasive Computing?

Tracking the device location

Device user relationship

Version control of devices and software that are out in the field

Software updates of existing devices

Installation of new software on existing devices.

Part B

1. Describe the principles of pervasive computing with examples.

<First list the principles one by one>

Decentralization

Diversification

Connectivity

Simplicity

<Then explain each topic in connection to pervasive computing >

Decentralization

Distributed systems

Having logic, database, control in a distributed style, not in a single machine-

centralized controller.

Synchronizing Information

Use applications on mobile devices and related data to be updated with networked

systems

Managing Applications

For example cellular phone network, tracking and billing are very essential

processes. Scalable managing application server and high end backend systems

are deployed.


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Diversification

Targeting specific needs

Clear move from universal computers (all in one) to diversified devices

challenging performance, price and functionality.

Diversified devices are aim at best meeting the requirements of a specific

group of users for a specific purpose.

Four alternatives to surf the web

Several tools might have some overlap in functionality: preferred tools for each

specific purpose.

1. One can use internet screen phone at home and enjoy multimedia effects.

2. For mobile internet access, a wireless connected handheld computer is the

choice even it has less graphical capabilities and small display.

3. Third one is WAP phone, a ultra-light and very handy and can’t enjoy

multimedia effects.

4. PC with single OS with multiple functionalities and work load can be

used for the same purpose ., but memory requirement is high when

compared to others…such case windows CE version can be employed

which requires a feasible memory capacity.

Managing the Diversity

It’s a challenge to manage device diversity, since each with different capabilities. The

delivery platform as many difficulties in providing common applications.

For example in case of e- shopping website in a WAP phone, user cannot see the

images representing services or objects.

Connectivity

A vision of boundless connectivity

Manifold devices are seamlessly integrated in an IT world without boundaries.

Exchange information through infra-red, data cable, Bluetooth.

Cellular phones with GSM, CDMA also involved in the environment.

Real life obstacles

Platform specific issues: obstacle for application and information exchange.

Devices with different persistent storage ranging from kilobytes(smart card) to

gigabytes(multimedia systems)

Different OS and variety of processors put various restrictions.


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Agreeing on common standards

Achieving connectivity and interoperability between devices is possible only when the

objects are supposed to follow common standards (ISO-OSI, etc…).

When it comes to application data exchange across devices, JAVA is the path finder,

since JAVA is platform independent.

Representation of data in variety of devices of multiple characteristics is resolved by the

introduction of XML.

Concepts like jini or UPnP help devices to discover suitable services in a network to

which they can delegate specific tasks. Automatic reconfiguration based on self-attach

and detach (plug & play capability) implies self-explained and easy usage of network-

connected utilities. With jini, networks turn into a dynamic and distributed system.

Simplicity

Device operations need to be easy, so that the user shall feel comfort with his

needs.

User Interfaces should not have complicated operations.

At present ―one touch ―keys are designed for user easiness.

Touch screen with relevant symbols, images help user to interact well.

Handwriting recognition, speech recognition enabled interfaces, simplifies the

user actions and makes him comfort with the system.

2. With neat diagram explain Biometrics system.

BIOMETRICS is not limited to fingerprint, it involves face recognition, DNA, Palm print,

hand geometry, iris recognition, which has largely replaced retina, and odor/scent.

Related to the behavior of a person. Examples include, but are not limited to typing rhythm,

gait, and voice. Some researchers have coined the term behaviometrics for this class of

biometrics.


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In this system, the user characteristic (fingerprint, voice…) is captured using a specific sensor

and its features are extracted to have a template .This template will be stored in the database

for reference.

In a simple system, when a user provides the characteristic like fingerprint, the system

extracts the features and compares it with the template stored earlier. If it is same the system

allows him.

Generation of reference value at the time of extracting features and template designing and

also at the time of comparison is subject to distortion.so there is always a possibility of

biometric system authentication failure.

FAR: False Acceptance Rate-probability that the system accepts the wrong user.

FRR: False Rejection Rate-probability that the system rejects correct user.

So we can have a combination of both SIM card (user id module) and bio-feature in the

system.

Here the FAR, FRR are very very low.

Key features of Biometrics:

•Universality – each person should have the characteristic.

•Uniqueness – is how well the biometric separates individuals from another.

•Collectability – ease of acquisition for measurement.

•Performance – accuracy, speed, and robustness of technology used.

•Acceptability – degree of approval of a technology.

3. Explain the Palm OS architecture and development cycle

Palm OS

Most successful OS for PDA

Available with palm, handspring, IBM, Sony..

Optimized limited number of features

Low (memory, CPU usage):leads to longer battery life

Version 3.5(256 colors)

Version 4.0(65k colors, Bluetooth support)


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OS features: User management: used as personal device with single user operating

system Task management: one application at a time and one can call other

application Power management: sleep/doze/running mode OS size:V3.5/1.4 MB/runtime memory:64kb User Interface: handwriting recognize/single button access Memory management: dynamic heap/storage

Development cycle

Supports c, c++(c almost/c++ a little)\

C-best choice for performance critical applications

C-simple and fast, Extensive system library

Free SDK based on GNU for windows,Mac,Linux

Commercial IDE –Metro codewarrior (editor, compiler,debugger,visual

graphical user interface constructor)

Palm applications are event-driven and synchronous

Several VM available KVM (Sun),J9 (IBM),WabaVM(Wabasoft)

Palm emulator: emulates a Palm H/W in a PC

Code is compiled –run-debug-edit-compiled

Until a ultimate program is achieved

Finalized code is downloaded to Palm from the emulator

4. Write short notes on

a.J2EE

In today's heterogeneous environment, enterprise applications have to integrate

services from a variety of vendors with a diverse set of application models and other

standards. They require bringing together a variety of skill sets and resources, legacy data

and legacy code.


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The J2EE platform breaks the barriers inherent between current enterprise

systems. The unified J2EE standard wraps and embraces existing resources required by

multitier applications with a unified, component-based application model.

Key features:

Java™ Database Connectivity (JDBC™) API

Transaction Service

Java Naming and Directory Interface™ (JNDI) API

Java™ Message Service (JMS) API

JavaMail™ API

b.J2ME

J2ME stands for Java 2 Platform, Micro Edition. The edition is targeted at small,

standalone or connectable consumer and embedded devices. The J2ME

technology consists of a virtual machine and a set of APIs suitable for tailored

runtime environments for these devices. The J2ME technology has two primary

kinds of components – configurations and profiles.

The configuration and technologies available for pervasive devices based on J2me:

Connected device configuration

Connected , Limited device configuration

Embedded Java

Java card

Real time java

c. Real time Java

Direct memory access: Java RTS allows direct access to physical memory,

making it similar to J2ME. One of the main target platforms of real-time Java is

embedded systems. This means that now you can create device drivers written in

pure Java. Java RTS defines a new class that allows programmers byte-level

access to physical memory, as well as a class that allows the construction of

objects in physical memory.

Asynchronous communications: Java RTS provides two forms of asynchronous

communication: asynchronous event handling, and asynchronous transfer of

control. Asynchronous event handling means the developer can now schedule the

response to events coming from outside the JVM. Asynchronous transfer of

control provides a carefully controlled way for one thread to interrupt another

thread in a safe manner.

High-resolution Timing: There are several ways of specifying high-resolution

time including absolute and relative time. Nanosecond accuracy is available for

time scheduling and measurements.

Memory management: There are two new types of memory areas, immortal

memory and scoped memory. Immortal memory holds objects without destroying

them, except when the program ends. Scoped memory is used only while a

http://docs.oracle.com/cd/E19957-01/817-2177-10/djovervu.html#wp18008






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process works within a particular section, or scope, of the program (such as in a

method). Objects are automatically destroyed when the process leaves the scope.

5. Explain Mobile IP

Mobile IP was developed as a means for transparently dealing with problems of

mobile users which enables hosts to stay connected to the Internet regardless of their

location.

Enables hosts to be tracked without needing to change their IP address

Requires no changes to software of non-mobile hosts/routers

Requires addition of some infrastructure

Have no geographical limitations

Requires no modifications to IP addresses or IP address format

Supports security

Mobile IP Entities

Mobile Node (MN)

The entity that may change its point of attachment from network to network in the

Internet

Detects it has moved and registers with ―best‖ FA

Assigned a permanent IP called its home address to which other hosts send

packets regardless of MN’s location

Since this IP doesn’t change it can be used by long-lived applications as MN’s

location changes

Home Agent (HA)

This is a router with additional functionality

Located on home network of MN

Does mobility binding of MN’s IP with its COA (care of address)

Forwards packets to appropriate network when MN is away

Does this through encapsulation

Foreign Agent (FA)

Another router with enhanced functionality

If MN is away from HA then it uses an FA to send/receive data to/from HA

Advertises itself periodically

Forward’s MN’s registration request

De-capsulate messages for delivery to MN

Care-of-address (COA)

Address which identifies MN’s current location

Sent by FA to HA when MN attaches

Usually the IP address of the FA


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Correspondent Node (CN)

End host to which MN is corresponding (eg. a web server)

Mobile IP Support Services

Agent Discovery

HA’s and FA’s broadcast their presence on each network to which they are

attached

Beacon messages via ICMP Router Discovery Protocol (IRDP)

MN’s listen for advertisement and then initiate registration

Registration

When MN is away, it registers its COA with its HA

Typically through the FA with strongest signal

Registration control messages are sent via UDP to well-known port

Encapsulation – just like standard IP only with COA

Decapsulation – again, just like standard IP

Mobile IP Operation

A MN listens for agent advertisement and then initiates registration

If responding agent is the HA, then mobile IP is not necessary

After receiving the registration request from a MN, the HA acknowledges and

registration is complete

Registration happens as often as MN changes networks

HA intercepts all packets destined for MN

This is simple unless sending application is on or near the same network as the MN

HA masquerades as MN

There is a specific lifetime for service before a MN must re-register

There is also a de-registration process with HA if an MN returns home

Registration Process


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Tables maintained on routers

Mobility Binding Table Visitor List

IP Tunneling

Data packets addressed to the Mobile Node are routed to its home network, where the

Home Agent now intercepts and tunnels them to the care-of address toward the

Mobile Node. Tunneling has two primary functions: encapsulation of the data packet

to reach the tunnel endpoint, and decapsulation when the packet is delivered at that

endpoint. The default tunnel mode is IP Encapsulation within IP Encapsulation.

6. Write a detailed note on device connectivity protocols

Wireless protocols: suitable for small hand held devices (PDA, mobile phones)

WAP (Wireless Application Protocol)

OBEX

IrDA

Bluetooth

IEEE802.11B(11Mbps)

WAP

Leading standard for information services on wireless terminals like digital

mobile phones.

WAP standard is based on Internet standards (HTML, XML and TCP/IP)

WAP consists of a WML language specification, a WMLScript (a light JavaScript

language) specification & Wireless Telephony Application Interface (WTAI)

specification.

WAP is published by the WAP Forum, founded in 1997 by Ericsson, Motorola,

Nokia, and Unwired Planet.


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Object Exchange (OBEX)

Devices can use this to exchange data objects. Designed to enable devices

supporting infrared communication to exchange a wide variety of data and

commands

An object pushes of business cards to someone

Synchronizing calendars on multiple devices using OBEX

Enables applications to work over the Bluetooth technology protocol stack as well

as the IrDA stack

RFCOMM is used as the main transport layer for OBEX.

Devices using the OBEX:

PC

Notebook

PDA

Mobile Phone

Bluetooth

Bluetooth wireless technology is a short-range communications technology

Key features of Bluetooth technology are robustness, low power, and low cost.

Can connect to other Bluetooth enabled devices located in proximity to one another.

Piconets are established dynamically and automatically as Bluetooth enabled devices

enter and leave radio proximity

A Piconet (can constitute 7 devices )

A device belong to several piconets

Features: Range of Bluetooth technology is application specific

Bandwidth upto 1 Mbps and operates in 2.4 GHz (ISM band)

Supports three digital speech channels simultaneously

a minimum range of 10 meters or 30 feet

Version 4.0 Low Energy, adopted December 2009

Version 3.0 High Speed (HS), adopted April 2009

Version 2.1 Enhanced Data Rate (EDR), adopted July, 2007

1 Mbps for Bluetooth low energy technology

1 Mbps for Version 1.2; Up to 3 Mbps supported for Version 2.0 EDR

Up to 24 Mbps supported for Version 3.0 HS

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