Context Aware In Symbian

Sangeeta Oswal1, Prathik Shetty2

VESIT MCA Department Chembur Mumbai

Sangita.oswal4@gmail.com

Shettyprathik_s@yahoo.com

Abstract— Context-awareness in mobile computing

paradigm are applications that can discover and

take advantage of contextual information (such as

user location, time of day, nearby people and

devices, and user activity).In this paper we propose

a context based mobile application for symbain OS

which provide service based on the context of the

user. we looked in depth at the types of context

used and models of context information, at systems

that support collecting and disseminating context,

and at applications that adapt to the changing

context. Through this survey, it is clear that

context-aware research is an old but rich area for

research. The difficulties and possible solutions we

outline serve as guidance for researchers hoping to

make context-aware computing a reality.

1.INTRODUCTION

With the appearance and penetration of mobile

devices such as notebooks, PDAs, and smart

phones, pervasive (or ubiquitous) systems are

becoming increasingly popular these days. The

term „pervasive‟ introduced first by Weiser (1991)

refers to the seamless integration of devices into

the users everyday life. Appliances should vanish

into the background to make the user and his tasks

the central focus rather than computing devices

and technical issues. One field in the wide range of

pervasive computing are the so-called context-

aware (or sentient) systems. Context-aware

systems are able to adapt their operations to the

current context without explicit user intervention

and thus aim at increasing usability and

effectiveness by taking environmental context into

account. Particularly when it comes to using

mobile devices, it is desirable that programs and

services react specifically to their current location,

time and other environment attributes and adapt

their behaviour according to the changing

circumstances as context data may change rapidly.

The needed context information may be retrieved

in a variety of ways, such as applying sensors,

network information, device status, browsing user

profiles and using other sources

1.1 WHAT IS CONTEXT?

Three important aspect of context are where you

are, who you are with and what resource are

nearby. Context also includes lighting, noise level,

network connectivity, communication cost and

bandwidth and even social situation for e.g. you

are manager or co-worker. Context is constantly

changing environment which can be:

Computing environment: available processors,

device accessible for user input and display,

network capacity, connectivity and cost of

computing

User environment: location, collection of nearby

people and social situation

Physical environment: lighting and noise level.

Time: Time of day, week, month of year

Schilit and Theimer [2] refer to context as

location, identities of nearby people and object,

and changes to those objects.

Brown [1] define context as location ,

identities of the people around the user, the time of

day, season, temperature etc.

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Ryan [3] define context as user‟s location,

environment, identity and time

Dey [4] enumerates context as the user‟s

emotional state, focus of attention, location and

orientation, date and time, object and people in

user‟s environment.

Context is any information that can be used

to characterize the situation of an entity. An entity

is a person, place or object that is considered

relevant to the interaction between a user and an

application, including user and application

themselves.

The use of the word “context” tends to be

vague because everything in the world happens in

a certain context. The term has been used in many

ways in different areas of computer science, such

as “context-sensitive help”, “contextual search”,

“multitasking context switch”, “psychological

contextual perception”, and so on. We only focus

on the context used by applications in mobile

computing.

1.2 SYMBIAN

Symbian [7] is a mobile operating

system (OS) and computing platform designed

for smartphones. Symbian was originally

developed by Symbian Ltd., as a descendant

of Psion's EPOC and runs exclusively

on ARM processors, although an

unreleasedx86 port existed. The current form of

Symbian is an open-source platform developed

by Symbian Foundation in 2009, as the successor

of the original Symbian OS. Symbian was used by

many major mobile phone brands,

like Samsung, Motorola, Sony Ericsson, and above

all by Nokia.

1.3 GLOBAL POSITIONING SYSTEM

The Global Positioning System (GPS) [8]

is a space-based satellite navigation system that

provides location and time information in all

weather conditions, anywhere on or near the Earth

where there is an unobstructed line of sight to four

or more GPS satellites. The system provides

critical capabilities to military, civil and

commercial users around the world. It is

maintained by the United States government and is

freely accessible to anyone with a GPS receiver.

The GPS project was developed in 1973 to

overcome the limitations of previous navigation

systems, integrating ideas from several

predecessors, including a number of classified

engineering design studies from the 1960s. GPS

was created and realized by the U.S. Department of

Defense (DoD) and was originally run with

24 satellites. It became fully operational in

1994. Roger L. Easton is generally credited as its

inventor.

2. PROPOSED SYSTEM

The phone‟s tracking system would provide

us with the location of the user. There are four

different ways by which the users location can be

found, they are Network Based, Assisted GPS,

Integrated GPS, Bluetooth GPS.

The system would then use the location

provided and filter the services accordingly.

Figure 1 : Workflow of context awareness In

Symbian

In the above figure Gadgets sense their

environment independent or with the aid of other

nearby entities (PROVISIONING), differentiate

what data is currently interesting or reusable

(REFINEMENT), model this data to an idea of

context (ANALYSIS), process it

(PROCESSING) and use the information for a

context-aware application (OUTPUT) and/or store

the data for a later usage (STORAGE) [13].

Once the user‟s location has been tracked, the app

will then use this location and filter the results

accordingly. This would help the user as unwanted

results are not displayed. It would be helpful for

Sangeeta Oswal et al, Int.J.Computer Technology & Applications,Vol 4 (4),678-682

IJCTA | July-August 2013 Available online@www.ijcta.com

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ISSN:2229-6093

the user if the results are displayed using the users

location, as the results would be near their vicinity

instead of results being displayed that are very far

from the user. This would also get the user more

interested as the can avail the services with great

ease.

The input would be given to the system in

terms of Latitude and Longitude. The system

would then process this and give the output in the

manner of a location.

The filtration process is such that the

services are displayed in such a manner that, first

the services in that area are shown then the

services surrounding that area are shown. The

services near the user‟s location are numbered

lower than the services that are far away from the

user.

e.g. The user is located near „Chembur‟ in

Mumbai, the user is feeling hungry and wants to

check if any offer is available for restaurants. It

would be sensible that the app locates a restaurant

that is near the location of the user rather than

finding a restaurant that is far away and would take

time to reach.

With the help of this context aware system, the app

would use the mobile device to find the location of

the user. Now as the user is in Chembur, the output

of the context aware system would give

„Chembur‟. The app would use this output as a

parameter and filter the restaurants in such a

manner that the restaurants in Chembur would be

listed first and the remaining restaurants would be

listed using the distance from Chembur i.e. the

nearby restaurants would be given higher priority

than restaurants which are far from it

3. DIFFERENT POSITIONING METHODS IN

SYMBIAN OPERATING SYSTEM

Four different methods are available in

Symbian platform. Each having different response

time, accuracy and so on. Each location accusation

method is identified with Uid and technology type.

To use any of the method, we have to create a

session with the positioning server and then we

create a sub-session with the positioning server.

When we create sub-session we can instruct the

framework what positioning mechanism we are

going to use. If we don't provide any specific

positioning method then the server uses the

positioning module with the highest priority by

default. If the highest priority positioning module

is not available or if it returns an error for a

position request then the positioning module with

the next highest priority is used. Following table shows different modules, name and it's Uid. [9]

Technology Name Used Uid

Network based 0x10206915

Assisted GPS 0x101fe98c

Integrated GPS 0x101fe98a

Bluetooth GPS 0x101fe999

3.1 NETWORK-BASED

Network Based techniques utilize the

service provider's network infrastructure to identify

the location of the handset. The advantage of

network-based techniques (from a mobile

operator's point of view) is that they can be

implemented non-intrusively, without affecting the

handsets.

The accuracy of network-based techniques

varies, with cell identification as the least accurate

and triangulation as moderately accurate, and

newer "Forward Link" timing methods as the most

accurate.

The accuracy of network-based techniques

is both dependent on the concentration of base

station cells, with urban environments achieving

the highest possible accuracy, and the

implementation of the most current timing

methods.

3.2 ASSISTED GPS Assisted GPS generally abbreviated as A-

GPS or aGPS, is a system that can under certain

conditions improve the startup performance,

or time-to-first-fix (TTFF), of a GPS satellite-

based positioning system. It is used extensively

with GPS-capable cellular phones, as its

development was accelerated by the

U.S. FCC's 911 requirement to make the location

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ISSN:2229-6093

of a cell phone available to emergency call

dispatchers.

3.3 INTEGRATED GPS Integrated GPS with no assistance. Can be

slow to make a first position fix, especially if you

aremoving or it has a poor view of the sky. Uses no

data connection.

3.4 BLUETOOTH GPS

Bluetooth GPS uses an external GPS

device. This device can be any kind of GPS device.

The phone is connected to this GPS device using

Bluetooth connection. Currently it only parses the

RMC message which is required in all GPS

devices. This gives the latitude, longitude, heading

and speed information but not altitude nor dilution.

4. WORKING

The GPS device obtains the users location

by tracking the device and finding its latitude and

longitude. This information is passed to the

Google APIS(http://maps.googleapis.com) along

with the longitude and latitude appended to this

URL.e.g.:http://maps.googleapis.com/maps/api/ge

ocode/json?latlng=40.714224,73.961452&sensor=t

rue

This technique is only possible for the three

techniques (Assisted GPS, Integrated GPS and

Bluetooth GPS) as only these devices have the

GPS device in them.

The Network based GPS uses the mobile‟s

network to pinpoint the location. The device is not

capable of directly providing us with the longitude

and latitude. Here we use the cell id which is

provided along with the user‟s sim.

A GSM Cell ID (CID) is a generally

unique number used to identify each Base

transceiver station (BTS) or sector of a BTS within

a Location area code (LAC) if not within a GSM

network

This cell id is then used to find the

longitude and latitude of the device.

e.g.: http://www.cell2gps.com/

This website gives the approximate

longitude and latitude of the device.

Using this data we can find the location of

the device. The location is not exact and can wary

from a few hundred meters to over a kilometer.

Fiqure 2: working of the proposed system

4.1 GEOCODING

Geocoding is the process of converting

addresses (like "1600 Amphitheatre Parkway,

Mountain View, CA") into geographic coordinates

(like latitude 37.423021 and longitude -

122.083739), which you can use to place markers

or position the map. [10]

4.2 REVERSE GEOCODING Reverse Geocoding is the process of

converting geographic coordinates into a human-

readable address.

The Google Geocoding API provides a

direct way to access a these services via an HTTP

request.[10]

5. CONCLUSION

Context-awareness is a central feature of ubicomp

systems. While the field of context-aware

computing is already growing rapidly, as more and

more sensors proliferate throughout the world, its

growth will accelerate and its importance will only

increase.

In Mobile computing, a user‟s context is very

dynamic. To promote a more effective use of

context, it is necessary to understand the

boundaries of context aware computing and help

application designer select context to use ,structure

context in applications, and decide what context

feature to implement.

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ISSN:2229-6093

The interpreted context is used to provide

smart service discovery and delivery to adapt

application behaviour. Context-aware systems

utilize the implicit perception of context found in

human and will revolutionize the way entities

interact with each other.

References: 1 Brown, P.J., Bovey, J.D. Chen, X. Context-Aware

Applications: From the Laboratory to the Marketplace.

IEEE Personal Communications, 4(5) (1997) 54-64

2. Schilit, B., Theimer, M. Disseminating Active Map

Information to Mobile

Hosts. IEEE Network,8(5) (1994) 22-32

3. Ryan, N., Pascoe, J., Morse, D. Enhanced Reality

Fieldwork: the Context-Aware Archaeological

Assistant. Gaffney,V., van Leusen, M., Exxon, S. (eds.)

Computer Applications in Archaeology

(1997)

4Towards a Better Understanding of Context andContext-

Awareness-Anind K. Dey and Gregory D. Abowd

5. Hull, R., Neaves, P., Bedford-Roberts, J. Towards Situated

Computing. 1st International Symposium

on Wearable Computers (1997) 146-153

6. Challenges in Implementing a Context-Aware System-M.

Satyanarayanan, Carnegie Mellon University and Intel

Research Pittsburgh

7. http://en.wikipedia.org/wiki/Symbian

8. http://en.wikipedia.org/wiki/Global_Positioning_System

9.http://www.developer.nokia.com/Community/Wiki/How_t

o_use_different_positioning_methods_in_S60

10.https://developers.google.com/maps/documentation/geoco

ding/

Sangeeta Oswal et al, Int.J.Computer Technology & Applications,Vol 4 (4),678-682

IJCTA | July-August 2013 Available online@www.ijcta.com

682

ISSN:2229-6093