Context Aware In Symbian
Sangeeta Oswal1, Prathik Shetty2
VESIT MCA Department Chembur Mumbai
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.
Sangeeta Oswal et al, Int.J.Computer Technology & Applications,Vol 4 (4),678-682
IJCTA | July-August 2013 Available [email protected]
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ISSN:2229-6093
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 [email protected]
679
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
Sangeeta Oswal et al, Int.J.Computer Technology & Applications,Vol 4 (4),678-682
IJCTA | July-August 2013 Available [email protected]
680
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.
Sangeeta Oswal et al, Int.J.Computer Technology & Applications,Vol 4 (4),678-682
IJCTA | July-August 2013 Available [email protected]
681
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 [email protected]
682
ISSN:2229-6093