unit-5.pdf

DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

2 Marks

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.

2. 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 provides unauthorized access.

5. 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.

3. 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

4. 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

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Desktop PCs / Servers / Web TVs Kiosks Invisible computing devices / Smart interactive posters Wearable computers

6. 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

7. What are the key parts of the hardware of pervasive technologies? Power-provisioning technologies Display technologies Memory technologies Communication technologies Processor technologies Interfacing technologies Sensor Technologies Authentication Technologies

8. Define Low-power Device Technologies? Since 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.

9. 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)

o Light Emitting Diode based Displays (LEDs) o Organic LED based Displays (OLEDs)

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o Light-Emitting Polymer based Displays (LEPs) o Chip-on-Glass Displays (CoGs) o Liquid Crystal on Glass Displays (LCoGs)

10. 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.

11. 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.

12. 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.

13. List the characteristics of IrDA. Frequency band Security Transmitting capabilities Bandwidth Speech

14. 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.

15. 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.

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 meant by Bio-Metrics?

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http://searchcio-midmarket.techtarget.com/sDefinition/0,,sid183_gci212714,00.html

http://searchmobilecomputing.techtarget.com/definition/Palm

http://searchmobilecomputing.techtarget.com/definition/personal-digital-assistant

http://searchmobilecomputing.techtarget.com/definition/handheld


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.

18. What is a “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.

19. Challenges of device management in Pervasive Computing? Or issues 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

20. What are three steps involved in the process of Synchronization? Pre synchronization Synchronization Post synchronization.

21. What is meant by 2.5G technology?2.5G, which stands for "second and a half generation," is a cellular wireless

technology developed in between its predecessor, 2G, and its successor, 3G.

22. What are the 2 basic elements needed with respect to connectivity in Pervasive Computing?

The pervasive computing system needs at least two basic elements to be pervading everywhere they are required to pervade:

Computing elements to take care of computational needs Communication elements to interconnect these computing elements either through

wires or wirelessly (with / without mobility).

23. What is a ‘Haptic Interface’?Haptics are enabled by actuators that apply forces to the skin for touch feedback,

and controllers. The actuator provides mechanical motion in response to an electrical stimulus. Most early designs of haptic feedback use electromagnetic technologies such as vibratory motors, like a vibrating alert in a cell phone or a voice coil in a speaker, where a central mass is moved by an applied magnetic field. These electromagnetic motors typically operate at resonance and provide strong feedback, but produce a limited range of sensations24. Describe briefly about the tegic T9 dictionary mode

Merit / Significance: Requires lesser number of keystrokes for textual input due to support for predictive text by combining use of dictionary and linguistic rules‟

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embedding, resolution of word-ambiguity is supported through prompts, available in on-screen as well as mechanical forms.

Demerit: Requires sizeable software support and computing resources (instruction cycles and memory).

25. What are the major choices available for battery design in Pervasive Computing Devices?

Key issue: Size and weight of the batteries versus the power capacity and price

Bottleneck: Relatively slower advances in the battery technology compared to those in other fields like display and storage technologies

Major choices available: Nickel-Cadmium (NiCd: 12-27 hrs. standby time), Nickel-Metal-Hydride (NiMH: 16-37 hrs. standby time), Lithium- Ion (Li-ion:21-50 hrs. standby time), Lithium-Polymer Cell based batteries (> 60 hrs. standby time, flexible shapes) etc

26. Name some applications of pervasive computing(i) Retail(ii) Airlines check in and booking(iii) Sales force automation(iv) Health care(v) Tracking(vi) Car information system(vii) Email access via WAP and voice

27. How does the biometric authentication work in pervasive computing?The method that work with small sensors can be used in pervasive computing

space.finger print, speaker, signature can be used with pervasive.Biometric authentication system captures the user’s characteristics with a sensor.

They derive the features and compare with known reference. The output is Boolean. 0->Authentication fails 1->Authentication succeeds

28. What makes device connectivity possible in pervasive computing?A user interacts with the computer, which can exist in many different forms - laptop, tablets, terminals, phones, etc. The underlying technologies to support ubiquitous computing include Internet, advanced middleware, operating system, mobile code, sensors, microprocessors, new I/O (input / output), new user interfaces, networks, mobile protocols, location and positioning, new materials, etc

29. Give the other terms of pervasive computingUbiquitous computing, calm technology16 MARKS

1. Discuss the applications of pervasive computing

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There is lot of pervasive devices available on the market. The question is how to use the device in application. This section given the overview of what is possible and what is required.

The areas include(ii) Retail(ii) Airlines check in and booking(iii) Sales force automation(viii) Health care(ix) Tracking(x) Car information system(xi) Email access via WAP and voice

RETAIL In retail there is a need for faster and cheaper methods to bring goods to the consumer. Now –a-days the consumer can select large varieties of products and can buy from stores via Internet. Mobile computers are provided with bar code readers, which are used to track product during manufacturing etc.

Small devices and wireless network access will be suitable for modern business. When standardization of the device comes they will be cheap and more flexible.

Consumers currently use computers to select products. In future they will use the PDA and the pervasive devices in the domestic market. When complete the list can be sent to the super market, and purchase in delivered to the consumer. The advantage is

1. fast processing of data2. data mining can be done

Airline check in and booking Airlines have been using the internet to publish flight schedules and customers

check their flyer accounts and allow the travellers to buy the tickets directly. This allows direct relationship between the customer airlines.When the application is present on the internet only computer literate can access and the access is via pc. When the airlines application is available on mobile computing the customers can interact with the airlines.

Sales force automation

Mobile workers relied on their portable computers to access and process data on the road. As we have wireless modems this has enabled tem to travel and still access the enterprises. As we have potable devices with a simple interface and connectivity, they are easy to use, cheep and the organization can give more devices to more people. They can be used to access the organization critical data also. But the problem is the rendering qualities limited by the device.

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Health care

This is a crucial application where in new and complicated device is used only when they have a benefit to the patient. Doctors and others need to learn about the new methods and also to know to use the same.

PDA has been used in healthcare. They can integrate they can integrate into the hospital work and that of doctors routine. They can provide the latest patient data and information that took place a minute ago. These types of application are most sensitive. Integrity must be assured. The data should be exchanged only with restricted access. Health care systems are now using smart cards for patients and professionals. Tracking the use of bar codes has revolutionized the pro9cess in many industries. They are found in almost all good and products.

The format is 1-D bar code which encodes a few characters. This is universal. The other format available in 2-D barcode which allo9ws several hundred of characters of information to be stored and will replace stamps in the futures

Ex:Radio frequency tags can be attached to goods such as labels. They will be read electronically even from large distance. This RF tag has a clip and an antenna enclosed in a transparent plastic sheet less than an mm thick. This can be used to track luggage in airlines industry. As RF tag is cheap it can be attached to each luggage and can be detected at certain points o9n the journey. If any luggage gets separated from the passenger the airlines can immediately find out the current location of the luggage and do the necessary.

Car information systemCar manufactures have started using pervasive co0mputin technology. Currently recent car have 30 microprocessors on it. They can communicate among themselves. In future they can communicate to outside world. To connect the car with outside world a gateway is needed. OSGi is the open service gateway initiative is and open standard and can communicate with outside world. The I version of OSGi based on java and jinni technology. OSGi is the compatible with Bluetooth. Have home PNA, home RF, USB and WAP.

Email access via WAP and voiceThe most attractive application of mobile device is access email and calendars.

Now many mobile users would like to access their email at any time and at any place. A WAP enabled mobile is well suited to access email fields and to send responses WAP mail services must be tailored to small band width display and limited key WAP mobiles phones access the internet of mobile email service provide via a WAP gateway . Mobile email server hosts the applications. Creates WML output and handles http requests this interfaces with pop 3 mail server where the original email resides through a pop3 client.

The email session involves the following steps1. The user can accesses a mobile email server using a WAP profile and a start page

URL.

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2. the mobile email server verifies whether the user is registered by checking the phone number and UID and a password

3. The user requests email service and provides the pop3 password for the access the pop3 mail server. The mobile email server verifies the address of the server and UID in the user profile.

4. The server a accesses a pop3 mail server on behalf of the user and extracts the mail files for the user. A mail lists is created converted to WML and sent to the WAP pone for users selection.

5. The user selects a mail file and sends a display requests to the mobile email server.

6. the email server converts the email file to WML and forward it to the WAP phone for display

7. The user reads the email with a WAP browser.8. The user responds with the requester for more mail or deletion of mail or reply.

To access via voice the same steps above is needed Users dial to the voice gateway authentication is done using customer id and pin. Pop3 passwords are stored on the mobile email server. Voice xml data is transmitted to the vice gateway which hosts a voice browser and text to speech engine f0or text rendering.The mobile email server must be a trusted component because it has access to passwords and user mail. Mobile service providers may include the pop3 server and mobile email server together in their in their internet to avoid leak of passwords and sensitive mail.

2. Explain device technologies in pervasive computing

This section discusses the technology that influences the evolution of mobile device. The key technologies are 1. Hardware technology 2. Software technologies 3. Operating system and java platform

Hardware: Batteries Displays Memory

As the mobile devices are handy and small this imposes the size reduction in the hardware. The size of the input and output component contribute to the total size of the mobile device. Today both input and output components are integrated into the same package result in smaller sized mobile phones. But when the input and output are separated the size can be still reduce. (i.e.) display can be wrist watch etc. the alternative to key board should appear when size still needs to be reduced.

Batteries:

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The battery technology is developing at a slower rate when compared to other technologies. When advances were made they were replaced because of their power consumption. Few such technologies areNickel cadmium cell: This battery was used as rechargeable battery. Heavy and loose their capacity through memory effect. This is the older technology.

Nickel metal hydribe (NiMH)(1) Delivers battery with better capacity.(2) Less weight.(3) Has an environmentally friendly component.

Lithium ion battery Used in all stets of electronic equipment. Still lighter when compared to others. Better energy density. More power delivery.

Lithium polymer battery This uses a gel material for electrolyte. These batteries are made3 from few thin layers of gel. They do not need any casing. Hence the battery can be in any shape or size.

DisplayLCD are replacing CRT used in the part.

DSTN Dual scan DSTN is generally used in a PDA. This method controls display element via passive matrix addressing. This method consumes less power. Has superior display performance hence used in laptop.Future technology

OLED: light emitting organic diode. LEP: light emitting polymer technologies.

OLED Organic compound are used as semi conductor material. Selection of organic compounds made such displays as extremely thin and

flexible.

COG-chip on glassLCOG: chip on glass.LCOG: liquid crystal on glass.

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These integrate the pixels on the transmitter present on the layer of glass.They can used to manufacture extremely small displays where the pixels size is only 10 µm. Such are used with wearable computers

Memory Memory is becoming cheaper at the same time the demand from the application is increasing. The current trend in that it is possible to integrate several MB of memory into mobile services.

Storage of dataWhen permanent data is to be stored removable disk drives with 1 GB is available to store.Techniques followed in smart phones and PAD

They store O.S code and application data in non-volatile flash memory and battery backed RAM.

They are based on semi conductor technology. Hence they need less power and provide faster access. The capacity is from 2 to 16 MB. Expansion slots are available additional to be plugged in.Flash memory and static RAM can be used, frequently changed data is kept in SRAM.

Comparison of SRAM and DRAM (dynamic ram)1. Simple addressing scheme vice versa for DRAM.2. Lack refresh cycle.

Future technologiesUni transistor RAM

1. Combines both SRAM and DRAM.2. Hence higher capacity on smaller chips.MRAM Magnetio resivitive RAM.

FRAM ferro electric RAM. Processers

1. Due to improvement in the CMOS technology the smaller sized processors are delivered and higher number of transistors are integereted in a single chip.

2. The clock rate and the processing power availability has been increased steadily.

3. The low heat emission due to the core voltage.

Human-machine interface (Software technologies)

Navigation Haptic interface

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Keyboards Handwriting recognition Speech recognition

Mobile devices use keyboard and displays to interface with the users. They are much smaller and specialized for the application and the form factor of particular devices.Ex:

1. Some mobile devices have only number keys and few extra keys for built in menu

2. Some devices limit the number of mechanical keys to absolute minimum which is used to trigger the important application for navigation.

3. There are devices that have no display or keyboard. Such devices are called headless devices.

Navigation: To operate application in mobile de3vices the user navigates through menu structure.Example The integrated cursor key which delivers signal for all four directions by pressing or moving. Buttons can be operated withy thumb. The buttons can be turned vor pressed. For each step in one direction the menu navigator selects and highlights one of the entries. The entry is selected by pressing the buttons.

Haptic interface:The aptic interface is basically a rotating control control with force feedback and a push button integrated into one

Keyboards:Types:

Onscreen keyboard Fitaly Tegie T9 Octave

Handwriting recognition: Word recognition Character recognition Localization

Speech recognition:This is the most natural input method

3. Discuss biometrics concept

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Access to system must be secured against unauthorized use. User authentication is a key function. Classical authentication relives on what you are and what you know.Internet application relies on UID and password.How ever password can be stolen by

(1) Watching the user entering the password(2) During transmission.(3) Via access to system admin data.

The stolen password is hard to detect because nothing is removed. GSM phones are protected against unauthorized use through the SIM and PIN chosen by

the customer.The PIN is stored and checked in the secure environment of the SIM and is not transmitted. Intruder must steal the SIM and PIN to impersonify. Many users do not prefer PIN because when forgotten and needs a complex procedure.

To overcome such we use biometric authentication. These methods relay on what you are. (e.g.) finger print, signature, hand geometry, face recognition, iris scan.

The method that work with small sensors can be used in pervasive computing space. Finger print, speaker, signature can be used with pervasive.

Biometric authentication system captures the user’s characteristics with a sensor. They

derive the features and compare with known reference. The output is Boolean.

0->Authentication fails 1->Authentication succeeds

Generation of reference values and actual value is subject to distortion. The comparison of the data sets is complex and introduction additional errors. There is always higher chance that biometric authentication will fail.

FAR:

False Acceptance Rate is defined as the probability that the system will accept a wrong user.

FRR:

False Rejection Rate is defined as the probability that the system will reject a correct user.

For SIM with PIN the Far =0.01% FRR =0%

(1)When biometric system is tuned to achieve small FAR, it increasesFRR and service will be banned. DOS is acceptable if a reasonable exception path exists. (2)Biometric system has semantic problems (eg) service may be denied if finger is dirty or injured.

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(3) Hence biometric application is limited to application where adequate back up is present incase of DOS. (4)Susceptible to fraud unless the total system is securely encapsulated and communicates via secure channel.

Penbased device may use signature to verify and to secure access to device

For signature FAR =0.1% FRR =5% The system is prone to tampering because none of the systems are encapsulated in a secure housing.

4. Explain OS concepts in pervasive computing

Palm Os EPOC Windows CE QNX Neutrino BeOS Embedded LINUX

The core function of the pervasive device is determined by its operating system.

The major difference of operating system for pervasive devices from the user’s point of view.(1) Human machine interface(2) Speed.

The pervasive operating system the basic concepts of operating system.

TWO TRENDS FOR PERVASIVE COMPUTING OPERATING SYSTEM

(1) Personal use: Palm OS and windows CE. (2) For home use: Linux, BeOS

PALM OS:

Most successful OS for PDA. Available with Sony, IBM. Success is because it is designed specifically for PDA.Hence Known as Zen of PDA. Supplies only limited features. Due to the limited feature leads to lower memory and cpu usage. Hence longer battery life. Implemented on 16 bit Motorola Dragon Ball cpu. Current version is 4.0. Supports Bluetooth and 65,536 different colours.This will lead to multimedia PDA integrated with mobile phones.

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OS FUNTIONALITY:

Palm OS is a layered architecture. It has different horizontal and vertical layers. The micro Kernel encapsulates the hardware specified functionality. Hence the vertical layer are independent of the hardware. The vertical layer provide API for the applications to access the OS. They are (1)User interface: Graphical input/output. (2)Memory management: Database, space, runtime system, variables.

FEATURES OF PALM OS:

User management. Task management. Power management. OS Size. User interface.

EPOC: EPOC was created by psion maintained by Symbian. There are 2 versions. EPOC 16 and EPOC 32 for 16 and 32 bit processors respectively. The current version of EPOC is release 5 which is available for 16 bit and 32 bit processors. EPOC supports Unicode and can display 256 colours.

Core operating system:

EPOC is multitasking. The OS architecture is represented by the figure. The base layer provides the fundamental API. The middleware layer provides the component needed to support GUI and application. EIKON is the system GUI frame work. Final layer is the applications.

Operating system features:

(1) User management. (2) Task management. (3) User interface. (4) Memory management.

Windows CE:

This is an embedded O.S developed by Microsoft. Windows CE user interface is similar to that of windows user interface. The current version is 3.0. Windows CE is available for 32 bit processors. (e.g.) X86,ARM, power PC and MIPs of 32 bit processors. 3.0 offers a real time support, a smart card subsystem for PC/SC complaint readers windows CE is Unicode based and support gray scale and colour up to 32 bit.

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Features of windows CE :

(1) User management. (2) Task management. (3) Operating system size. (4) User interface. (5) Memory management. (6) security. (7) software development for windows CE

QNX Neutrino: The current version of QNX Neutrino is 2.1. This is a real time operating system and has micro Kernel surrounded by a collection of optional processes that provides POSIX and UNIX compatible system services.

Core operating system functionality:

The core operating system consists of a micro Kernel which has a size of 12KB The Kernel provides 4 services

(1) IPC(2) Process scheduling(3) Low level network communication.(4) Interrupt dispatching

Features:

(1) User management.(2) Task management(3) User interface(4) Memory management(5) Addon features(6) Software development

BeOS:

The goal was to create a media operating system. The current version is 5. It offers multiprocessor or support to integrate sound and graphic, processors, 64 bit file system to deal with huge amount of data. BeOS can be used for internet personal access device provides the multimedia foundation.

FEATURES of BeOS:

(1) User management.(2) Task management(3) Memory management(4) Addon features(5) Software development for BeOS.

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Embedded LINUX:

This is a stripped down LINUX O.S with support to pervasive devices. There is no standard for embedded LINUX. There is a consortium which promotes embedded LINUX systems. Used in MIPs, ARM, Motorola, Intel processor.

Core operating system functionality:

Configurable Kernel Scalability Networking OPERATING SYSTEM FEATURES:

(1) User management.(2) Task management(3) Operating system size(4) User interface(5) Memory management

5. Give the overview of device connectivity

Protocols

Wireless protocols-WAP/WML-OBEX (Bluetooth)

Mobile phone technologyMobile internet protocolSynchronization & transaction based protocolsDistributed servicesMessage & transaction based protocols

SecurityConceptsDevice securityServer side securityCryptographic algorithms

Device managementDevice management challengesSoftware distributionApproaches

6. Discuss the concepts of security & device management in pervasive computing

Security

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This section discusses with the basic security concepts and tells about how they can be implemented.

The concepts are1. Identifications2. authentications3. authorizations4. transactions5. non repudiations

Identifications

The identifications is needed to identify the users accessing the accessing the server using pervasive devices.

The common method is to use user identifications which can be entered or stored in the device.

If the user has a mobile phone we can use the phone number.

If the user ahs certificate then the certificate unique id can be used. These ids must be mapped to user’s id.

Authentication:

Authenticati0on is to9 prove that who the individuals say they areThe most common authentication is user id and password

Authentication can also be done by sim. The authentication is executed between the smart card on the client and the authentication software on the server side.

Password provided by the user has to be given to smart card before a signature can be obtained to ensure authentication.

Authorization

Authorization is to define principals and associate permissions that these principals possess. Authorization should depend on the device and authentication transaction.

1 .Transaction authorization 2. Digital signature endorsed by a password3. Transaction authorization numbers

Non repudiation

The user cannot falsely deny later that the user has authorized a transaction Digital signature can be used to prevent repudiation.

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* Device security* WAP phones

Device management:

Here we discuss about the major challenges of devices management example of device management software distribution and approaches to solve the device managementChallenges of device management

The serious challenges posed are1. tracking device location2. device user relation ship3. version control of device and software4. software updates of existing devices5. installation of new software on existing devices6. providing secure access to device information

Approaches1. hardware capabilities2. hardware and software version management3. library management 4. device are not always connected / unstable connection5. insecure connection

6. Explain pervasive web application architecture

The architecture proposed for pervasive computing application support multiple devices like pl WAP PDA etc voice only enabled phones access the web server through voice gate way .

The problems include

1. Variety of Device 2. Mark up languages3. Authentication method

The challenges faced are many. For example users may have different devices that appear and behave differently. Hence applications that support pervasive computing should adapt to the device that are used hence application must provide content in a form that is appropriate for user’s specific device.

If the device capabilities differ, the interaction between the user and the web application has to be tailored to that of the device capabilities to provide good usage.

Hence architecture should

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1. Filter unnecessary; information2. flexible to adapt to different user devices.3. Adapt to scalability4. Satisfy performance

Scalability and availability

Scalability and availability are major issues that should be catered in pervasive computing application

Availability

The services should be available at all times when they need it they assume that it does not work and switch to another service provider.

Development team needed to develop pervasive computing web application

The team needed has1. business logic designers2. user interface designers3. application programmer4. experts

Pervasive application architecture

Pervasive computing application has another complexity i.e. devices are different from each other. There cannot be a command controller that will fit in all devices. To support multi controllers the server will be a dispatcher to invoke the appropriate controller based up on the device.

Hence to avoid duplication of code for invoking a model function between controllers we use a command pattern

Command Command is a bean with input and output properties.

Securing pervasive computing application

Web applications supporting pervasive devices should be secure by having encryption authentication and authorization.

The architecture processes the client request on the application server securely. The process of security addresses UID authentication and authorization

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All incoming requests are form the device connectivity infra structure. the infra structure include the different kinds of gateway that convert device specific requests to a http request which carries information about device type desired language desired reply content type.

Examples of gateway are 1. voice gateways 2. WAP gateways3. gateways for connecting PDA

Securing pervasive application using an authentication proxyTo have an secure pervasive computing application an authentication proxy along with security policy; engine can be used

The device can be connected 1. directly to the authentication proxy2. via an appropriate gateway

Advantages of centralized authenticationThe acce3ss rights are managed at a central place a such that the application servers are not overloaded the interaction can be either for the first time or subsequent time

Advantages of authentication proxy1. Authentication can be performed in a militarized zone.2. through the outer fire wall requests can flow only to the proxy3. the inner fire wall requests can flow only to the application servers that come

from proxy

Securing pervasive application using a frame workHere we discuss how a frame work can be sued to support secure pervasive application

Assumption1. MVC pattern 2. JSP application logic patter

Web application bade on MVC pattern

JSP based application Secure servletSecure servlet inherits form http servlet overwriting the service method

The service method of the secure servlet uses the security polity class to perform the security check.

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The secure servlet class implants 4 methods that provided the information needed by security policy as a basis for decision

1. get action method2. get authentication method 3. get device type method4. get role method

Secure JSPSecurity stateSecurity policy

7. How computing access from PCS and PDA? /smart-card based authentication

Here we discuss how the users connect to the internet via PDA personal digital assistants.

There are approaches on how the users connect to the internet via PDA1. Synchronize the menu to the PDA.2. Use a local data base and native application to handle the menu. The user will

be connected only when synchronizing the data and submitting a request.3. WAP is used to show the actual menu.The user will be connected while browsing the menu and submitting a request.

Access from PC – Smart – card based authentication through Internet

In this case, we shall use smart-card authentication with a public key. Customers are provided with a smart-card with an inbuilt chip. The card contains the following:

1. Private key for generating digital signatures2. Certificate containing data about the customer3. Public key associated with the private key of the customer4. Signature for all these dataDiagram – Refer book

Implementation is for synchronized devices: TOOL:

The tools used are iSilo and iSilo web.

Application Design:The user installs the iSilo web application on the pc and iSiloclient application on

the PDA.The new channel has to be configured has once which is used to update the data

fromthe web shop when ever needed. When the PDA is connected to the networked pc the HTML page are transferred to the pc and converted to the internal iSilo format. They are synchronized to the PDA in asinle file then onwards the pc and the network connection are not needed any more. The user can access the page through the iSilo client application

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MENU STRUCTURE: This model follows the HTML version of the menu. This implementation is

designed for the users who do not want to connect to the web shop frequently and want to keep the product list on their device for reference only. Here no personal data is stored and no registration is need.

Due to the small display on PDA, the items need to be categorized. To keep a small page size the present in a separate page which can be reached through hyperlink.

DATA: There are page for connecting the PDA to server. The pages are in HTML format but limited tags are used and image size in small. They can be viewed by standard browsers.

Web shop server detects the desired mark up format for use on a PDA looking at the user agent string.

Here we should have installed the iSilo client application on the mobile device. The page are received and downloaded to the PDA using a networked pc running the isilo web tool.

This tool allow the channel to be defined which represent a collection of pages from local file or web. The user need to configure the channel with the URL and select the option for conversion to the iSilo format. The page are load from the web, converted to the internal, compressed isilo format. During the next local synchronization they will be copied to the user‘s palm OS device. Once transferred then the PDA can be disconnected from the network can be browsed through iSilo client application.

THE LOOK AND FEEL:The HTML page when looked on the PDA screen will look different.They lack

colour and rendering is different PDA cannot handle tables,hence they place each table cell on a separate line.

IMPLEMENTATION:The menu is created using standard HTML.scaled down images are embedded on

the top of the page.The table is displayed without border,all the element on the page are centered. Instead of using static HTML code web shop uses servlets,JSP to genetate the mark up.

CONCLUTION: There is no interaction between the mobile device and the web shop once the

menu has been downloaded. The user can use the hypertext document to browse through the menu, when an order is clicked in the web shop the application runs completely disconnected.

ADVANTAGE: 1.So simple,every uses with iSilo tool can get the menu from web shop.

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2.The user does not need an online connection. 3.They can access the data at any time without network delays.

DISADVANTAGE: 1.The data is present in out dated. 2.The user need to update the channel from time to time.They will not receive menu updates.This is a significant problem for a web shop.

IMPLEMENTATION FOR INTERMITTENTLY CONNECTED DEVICE: The second implementation of PDA ccess to web shop allows the user to download the menu to the mobile device which can be used for reference when postioning an order.Here new order are transmitted directly from PDA to webshop and during the synchronization the PDA date base is updated.TOOLS USED: Two important component are needed for this approach.

1.Ther heeds to be a synchronizeation mechanism. 2.The database engine for the PDA. For synchronization we use IBM mobile connect synchronization server.To have a database engine we can use IBM DB2.or Orcale etc. The tool used will be metro work code warrior.

APPLICATION DESIGN: The PDA connect to synchronization sever via a modem.The synchronization server access the RDB is a base server.It processes the updata between the prouct list stored on the server and the local copy on the client.It supports to handle update etc.,

MENU STRUCTURE: This method proper users authentication.All personal data are kept confidential.No login are needed because synchronization server perform user authentication.

THE DATA: The prodect data are stored in RDB accessed by synchronization server.

THE LOOK AND FEEL: After the user has configured the mobile connect client application with the synchronization server address the user connects the database is replicated to the device for the following connects only the name currently connected is sent to device.Via this application knows who the currenent user is.But There is no PI to query or modify synchronization server settings.

CONCLUSIONS: 1.Ther is way to update the data from web shop, when ever customer connects to the synchronization server.

2.The application does not need a permanent network connection.3.This approach allows the highest degree of customization.

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DISADVANTAGE:1.Need a special application fro each PDA we want to support

IMPLEMENTATION FOR CONNECTED DEVICE:The goal of this is to give the most up to data view of the menu available and to

make it as device independent as possible.But compromise has to be done on user interface.

TOOLS:kBrowser

APPLICATION DESIGN: This shows hoe the PDA connects to the web shop server and receives back

WML pages.A modem with infra red beam is used to connects to a WAP gateway which

handles the conversion between HTTP and WAP. All web pages are available from the web server in WML format and all images are encoded in the WBMP format. The web server connects to the product database and renders data using JSP.

MENU STRUCTURE:

The menu stru7cture is similer to pc version since both use a browser to access the webshop. After the initial login the complete menu can be displayed. PDA offers easy way to enter text, the UID and password can be alpha numeric.

The shop is categorized hence avoids scroll through long lists.

THE LOOK AND THE FEEL:

The appearance of WML based is same as that of WAP. The graphics and lay out are adapted to that ofPDA. The screen resolution in front 160*160 to 640*240 pixels. After log in the main menu is presented to the user. The favorites are immediately available. The items are categorized.

IMPLEMENTATION:

Web server has to prepared to deliver WML. It can detect the browser user by checking the user agent straight that is part of each HTTP request. If it detects that a WML browser is used the server will switch from HTML to WML by calling appropriate JSP. To test the WML pages and to convert the graphics we use Nokia WAP tool kit. All graphics have to be converted into WAP specified WEMP format.ADVANTAGE:

No internal database is requied on PDA because all data remain in the server. Orders are compiled and handled while connected to the server. The latest data will be always available.

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DISADVANTAGE:

There is no way to check history or status when offline.To decrease the comlexity (i.e) the number of format tools. We should use HTML

but this needs HTML capable browser. If the browser supports only a subset of HTML it will still need web server to handle access via PDA separately by generating an appropriate HTML subset, and a layout for the PDA screens.

8. How computing access from WAP?

Here we discuss how the application is made to access WAP browser using mobile device.

WAP FunctionalitySimple interactions with the service the internet can be done using WAP device.

As an example we study automated ‘Uncle Enzo’s pizza hut server.

The advantage of such device is that the boot time is short and can be placed in pockets and can able to place order with Uncle Enzo’s shop.

From this organization point view the advantage is that the organization need not the recruit additional personal for process.

To access via WAP device the application must be optimized for usability and efficient user interface. As the display is small it is difficult to display the full list of menu items.Hence only a short list of menu items can be displayed.

They do the process called quick where by the customer has to customize the favourites if not it is at the recommendation of the chef.

To list out the favourites the customer need to use the PC browser. The other administration function can be accessed via pc only.

For example when we consider the function website of Uncle Enzo’s shop only the highlighted ones are displayed in the WAP client.

When the the customer navigates to the shop website via WAP device only a few function appears.

(i.e) Logo,login,authentication is done via PIN,menu,quick addressing and confirmation is displayed.

The other functioin gets displayed only when accessed via pc.WAP interface should integrate with the overall architecture.The limited subset of function is provided in WAP device.

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The figure shows the servlets constituting the overall architecture of the organization.Three servlets constitute entire system architecture viz registration,login, shop.To this we have the controller then the exact function.Infra Structure

In addition to the internet infra structure needed to deploy the web application, the device needs WAP geteway and a dial in hardware.

To have the WAP connectivity there are two choices for the business(i) Setup their own equipment for WAP connectivity.(ii) Relay upon the services provided by the network operators.

Here the service provider the requirement is that the phones are to be configured to access their gateways.

When the organization wants to deploy the application quickly the decision is to rely upon the gateway provided by providers.

Here no special equipment is needed when choice 2 is opted. Request from WAP Phones move to WAP gateway of the service provider. They are converted to HTTP request which flows to application server.

The software present in the application server detects that the request is from WAP phone and return HTTP response with appropriate document type and content to WAP gateway at the network provider.

Finally the WAP gateway converts the response to a WAP response and send back to the device.

THE TOOLS NEEDED FOR Implementation

WML is supported today’s mobile phone is a language based on XML.WML can be edited using XML editors or WML editors are provided with WAP tools kits.WAP application tool kit can be used to convert images to the WBMP format needed by WAP phones.To create a complex WML pages it is convenient to create an initial version of the WML pages using a WAP tool kit.

When the WML pages have been created tools are needed to deploy and test them.

After deployment the WAP emulator is connected to application server to test the application. The WAP tool kit have the capability to display WML source for any deck received from the application. This indicate the errors which is helpful for debugging.

At the last only WAP application are tested on real phones. For usability task the test are conducted on individual targets devices.

Extension to improve the speed usabilityAuthentication mechanism

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The application uses s ID and a numerical password for authentication. This has the advantage because it can work on any phone. But from the user point of view it is inconvenient.The alternatives to this approach are

Customer ID using MISISDN numbers:MISISDN is a number to identify the device. Hence this is a unique number. This

MISISDN can be considered as a password.

The UID will be the telephone number.When logged in via mobile phone number this redirects to the shop to find the

equivalent MISISDN number.

Customer authentication using WIMWIM allows secure authentication via internet. During registration the user will have to registrator a WAP certificate with the shop which gives the shop a mapping of certification to user ID number.

When a customer with a WIM enabled phone logs onto the shop may send a WML page, WML script generates a signature over a random challenge from the server using appropriate private key export the certificate for the key and signature and WAP certificate back to server for authentication.

Multipart responsesMultipart response allows server to chain files and return to the client in one

response.Advantage:

Reduce the number of request from the mobile device to the server.

Input validation using WML script

Application needs inputs to be validated. WML scripts can be used to validate user input on the WAP device to reduce the number of transactions.

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Anna university Question papers

B.E/B.Tech. DEGREE EXAMINATION, MAY/JUNE 2013

Part A1. Define Biometrics (Page : 4)2. Name some applications of pervasive computing (Page : 5)

Part B1. How is server side security done in pervasive computing? Explain in it detail (Page : 16)2. Write down the functionality of WAP in access via WAP (Page : 24)


Part A1. What are the key parts of the hardware of pervasive technologies? (Page : 2)2. How does the biometric authentication work in pervasive computing? (Page : 5)

Part B1. How is security in pervasive computing established? Explain them in detail (Page : 16)2. Write short notes on the smart-card based authentication via the internet (Page : 21)


Part A1. What is meant by pervasive computing? How is it done? (Page : 1)2. What makes device connectivity possible in pervasive computing? (Page : 5)

Part B1. (i) Explain the operating system issues related to miniature devices. (Page : 13) (ii)What are the design and implementation issues in device connectivity aspect of

pervasive computing? Explain. (Page : 16)2.Explain the various soft surface and semi-soft-surface-based based display systems and

technologies. (Page : 9)


Part A1. Give the other terms of pervasive computing (Page : 5 & 1)

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2. How biometric signals are used in pervasive computing? (Page : 5)

Part B1. Discuss the various issues and challenges for interfacing the human machine in

pervasive computing. (Page : 11) 2. Describe the various problems for security and device management in pervasive

computing. (Page : 16)


Part A1. What is Pervasive Computing? (Page : 1)2. What are the various issues related to device management in pervasive computing? (Page : 4)

Part B1.(i) Describe the various hardware components involved in pervasive computing

devices. (Page : 8) (ii) Explain how a pervasive web application can be secured using an ‘Authentication

Proxy’ (Page : 17)2(i) What are the applications of pervasive computing? Discuss any two of them. (Page:6) (ii) Explain how pervasive web application can be accessed via WAP. (Page : 25)

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unit-5.pdf

Documents

mobile computing devices

pervasive computing

fixed computing devices

roaming environment

lowpower device technologies

multiple devices

users environment

mobile phones