Mobile and Pervasive Computing - Assignment

CS710 – MOBILE AND PERVASIVE COMPUTING

ASSIGNMENT # 1

Question No. 1                                    15

Distributed computing is the major area whose concepts are inherited to the mobile and pervasive computing. Justify by giving details of some of these concepts. How these concepts are used in mobile and pervasive computing?

Answer to Question No. 1

            Networking, wired or wireless, can be defined as two or more than two nodes communicate among each other. Example of a graph can explain it more precisely where computing components and communication means can be presented as nodes and edges respectively. These terms “Distributed Computing”, “Mobile Computing” and “Pervasive Computing” are inter-related and share some common properties. These can be further elaborated as under:-

1.                  Distributed Computing

a.                   It is a static system where components are connected with wire.

b.                  Base stations are the nodes and wire is the source of communication among each other.

c.                   If one station breaks down then the network may get non- operational for a while temporarily in that region only.

d.                  The LAN and WLAN leads to the distributed system.

e.                   Internet, intranet, ATM machines (bank), etc are few examples of distributed computing.

f.                   There are three major characteristics upon which its structure is standing and these are:-

i.                    Concurrency

ii.                  No global clock

iii.                Independent failures

g.                  Concept of “client server” where all resources are managed centrally at server side and it is the hallmark of this system.

h.                  There are number of benefits of this system like resource sharing, scalability, fault tolerance and 24/7 availability and above all the high speed performance.

i.                    All components have access to the base stations all the time without any major hindrance.

j.                    The servers hold the data which is made available to all the clients.

k.                  Since the system is wired so security is also an aspect which has to be taken care of.

2.                  Mobile Computing

a.                   It is an upgraded version of distributed computing but not static. The system is further miniaturized and addition of wireless networking leads to the mobile computing.

b.                  Mobile units are connected wirelessly with the base stations and among each other. The communication is via spectrum on some frequency.

c.                   Since all or some components are on move all the time so there is a requirement of a dedicated software which takes care of certain problem areas.

d.                  Wireless connectivity is done at short range like infrared data association (IrDA), Bluetooth, WLAN (IEEE 802.11.a,n) and long rage like 3G, EDGE, 4G etc.

e.                   Implementation of the concept of “any time”, “anywhere” and “with anyone” in a befitting manner.

f.                   Got limitations of computing power, battery power, memory, storage space, bandwidth and latency, interface elements like screen size or input model.

3.                  Pervasive Computing

a.                   It is an upgraded version of mobile computing and added its own properties to it.

b.                  It can be explained as the absence of the “Presence of Computing”.

c.                   In other words all the computing is done in the back ground and nothing is visible to the users. They do use it as a routine life activity and don’t know about what happens once they push a button of any appliance under their use. They just get the work done that may be getting some service physically or virtually. So it is also known as invisible computing.

d.                  The concept of smart space is integrated where all places around us are connected through sensors (wifi) which can be accessed by all users.

e.                   Due to the smart space environment a huge number of users is obvious so problems like bandwidth congestion, energy crisis and distraction is not new thing. This aspect invites the scalability problem which is addressed by localizing it.

4.                  Keeping in view the above discussion, it is evident that mobile and pervasive computing are conceptually based upon distributed system. The concepts of distributed systems which are used by mobile and pervasive computing are as under:-

a.                   Remote Communication.        As of distributed computing nodes are at some distant places from each other connected with wire. Mobile and pervasive computing are also at some distant places from each other but are wirelessly connected.

b.                  Fault Tolerance.          This property is held by all as if one or some components face failure due to any reasons then it has no effect on the communications of others.

c.                   High Availability.       Since all the stored data is replicated therefore data is available all the time from any source. The data is accessible all the time. A system of recovery of data is present so the concept of high availability with distributed computing is enjoyed by the mobile and pervasive computing as well.

d.                  Distributed Security.   This is very important aspect as wires and components can be secured from any attacks but it is quite difficult to secure data which is in the air. Mobile and pervasive computing faced this problem but it is addressed amicably. The famous “AAA” lines of defense (Authentication, Authorization and Auditing) considerably reduced the danger.             

Question No. 2                                    15

A website has different views when viewed through desktop and mobile devices. Give the basic parameters considered while developing the sites for mobile devices. 

Answer to Question No. 2

            The websites give two different looks, one for desktop computers and other for mobile devices. It is observed with concern that there is a huge number of users interacting with internet through their mobile devices like mobile phones, smart phones, PDAs, tablets, pagers, digital still cameras, digital camcorder etc. In the subsequent paragraphs the parameters are highlighted which should be considered once such sites are developed:-

1.                  The Markup Language.           Since mobiles devices are developed by different companies with different operating systems so some devices browsers support XHTML (extensible hypertext markup language) and some WML (wireless markup language) etc. So it has to cater for that any device interacting with websites should not face language problem.

2.                  Device Screen Size and Resolution.   All the mobile devices are in different shape and sizes so they differ in display like blackberry, android and Symbian devices support 320x320, 320x480 and 480x360 resolution, whereas linux window mobiles 6 and window 7 phone devices support only 480x800. So the websites should have a mechanism which adjust automatically for such devices.

3.                  Keep Pertinent Information.   As the mobile devices have very reduced place to display therefore Keep only relevant information on the pages.

4.                  Link and Font Sizes.   Since the touch screen devices are at increase so the links and font size should be about 32 pixels which is comfortable and easy with the fingertip touch.

5.                  Legible Text Size.       Since the screen is too small so the user has to concentrate while reading the text. The size of the text should be legible, recommended size is around 32 pixels.

6.                  User Interface (UI) Size.        UI size should be designed at much larger scale than normal for the mobile device. Users normally tab and drag the icons which should be accommodated comfortably.

7.                  Removal of Un-necessary Items.        Animations and images should be removed from the pages which reduce the speed of opening up the pages. By doing so websites loading time would be enhanced considerably.

8.                  Header and Footer.     There are number of links and useable items which at time are not required but once needed should be handy. Like a calculator, contacts, message box, setting, browser etc may be required at any time so header and footer can be utilized to serve the purpose. Icons of such links should be present at header and footer for easy access.

9.                  Mobile Web Applications.      Should be lightweight so that user should not hang with speed. Should give quick response and cater for the mobile device’s capabilities as well as constraints.

10.              Mobile – Friendly Forms and Images.            There is a need once user has to fill up some forms so the form filling application should be lightweight and all boxes should have enough space for writing. Combo box should keep the required information handy. User just scroll down the box and click on the data. Like filling up of date, month etc. 

11.              Single Page Applications (SPA).        It is best suited with mobile devices, as full page is not downloaded and just the assets showed up to the users.

12.              Online Emulators.       The websites should be tested before launch. There are number on online emulators available for testing the new born websites for mobile devices.    

In a nutshell, all above observations should be catered for in order to develop a healthy and reliable websites for mobile devices.

Question No. 3                                    20

Virtual university is launching a project using mobile and pervasive computing platform. You have to make decision to choose an environment from desktop, laptop and cell phones. Which one will you choose? Why the other platforms were dropped? Keep the cost, battery timings, mobility and computing speed parameters in mind. 

Answer to Question No. 3

1.                  A project of mobile and pervasive computing platform is to be launched by the VU and environment is to be selected from three namely desktop, laptop and cell phones. The selection should be based on number of pre-requites like cost effect, battery timings, mobility, computing speed, utility, usefulness, accessibility, productivity, reliability and durability etc. It is very hard to come to some conclusion without any thorough analysis. Since the operating systems among these three environments are not that relevant in terms of usage, cost effect and somewhat are almost alike, therefore software does not matters and area of emphasis should be the container which hold it.

2.                  By carrying out the analysis the picture will be clearer and a decision will be easy to take. Following are the details:-

a.                   Desktop

i.                    Merit.  It provides the best working atmosphere as it is static and stable and a set place to work. It is cost effective, reliable, available, no battery issue and durable. Replacement of any item is very easy and not costly like monitor, keyboard, mouse and CPU. High speed at the lowest cost can be achieved. It’s handy which means can be carried along easily.

ii.                  Demerit.          The foremost and ultimate problem which is the worst one is the immobility. It can’t move and requires a fixed place where it can operate. Another problem is in case of electric failure it has no backup. Although UPS can give some support but not reliable.  

b.                  Laptop

i.                    Merit.  Laptops are portable, durable and easy to handle. The handling is easy as everything like monitor, keyboard, mouse and CPU are at one place. Laptops can be used as desktop by just placing it at the table. High speed at reasonable cost can be achieved. At present windows 8 laptops have the touch screen capability which makes it more attractive. Have the capability of wifi, WLAN and Bluetooth capability.  

ii.                  Demerit.          They are costly than desktop, not durable and delicate / fragile also. Since a handy item therefore chances of steeling/ theft or lost is there. Difficult for the people to play with integrated keyboard and mouse as they were used to with desktop. Issue of battery life is another aspect which is catered for with additional battery as backup. 

c.                   Cell Phones

i.                    Merit.  These are very handy and easy to handle. Reliable, cost effective, portable and useful. High speed can be achieved with good processor. Very useful to maintain calendar management, reminders and alarms. A good monitoring device for workflow, tasks and emails. Besides these benefits telephone facility is additional charm. Smartphones and android system put the cell phones to another level.

ii.                  Demerit.          They are very small in size so small screens are not at all suitable to work. The applications face compatibility issue once dealing with other devices.  Very delicate and handy item therefore chances of steeling/ theft or lost is there. Small keyboard and buttons are another are very difficult to handle. Battery life is very important issue which is limited. Not a durable and reliable item.  

3.                  Nexus to above it is observed that cell phones are out from the race of selection. Now competition is among the desktop and laptop. Although desktops enjoy more computing speed with no battery issues in a very less price but static and immovable. On the other hand, laptops enjoy more computing speed with limited battery power at reasonable price but portable and easy to carry along anywhere and everywhere. By doing some trade-off, laptops are better option keeping in view the VU requirement of a mobile and pervasive platform.

4.                  Recommendation.       Keeping in view the above discussion, I will opt for Laptops to be incorporated in the VU project of mobile and pervasive platform.