LOCATION INFORMATION MANAGEMENT

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07 August, 2010 Location Information Management, HaniNaguib, George Coulouris

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LOCATION INFORMATION

MANAGEMENT

Presented By:

Gurpreet Kaur 09609073

Prateek Gupta 06502920Shishir Yadav 09609074


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THE VOYAGE

What is location technology.

Why information management....

The project.

Its Architecture.

Modeling of Location Information..

Abstractions from the Service.

What are different levels of the Information System and their use.


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LOCATION TECHNOLOGY

Location technology is something which provides location information about any

locatable objects. All location technologies generate sensor events in response to

changes in the location of locatable objects. There is wide range of existing location

technologies and more are under development . Some of the existing technologies

are

Active Badge system [HH94], provide information about the presence of a user in

a region or a room.

Active Bat system [HHSW+99] are much more precise, providing information that

is accurate to a few centimetres.

Generated sensor rate depends on technology we are using as it would be very high

in precious location technologies.


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WHY INFORMATION MANAGEMENT ?

As we know good location technologies generate sensors in very high rate .Out of

which only few sensor events are of interest to any specific application . So we need

management of the data gathered by location technology. And some other reasons

are

Multiplicity of location information

A filtration mechanism is needed that will enable applications to see only relevant

data .

A uniform way of making this information available is location-technology

independent fashion is necessary because there are lots of different technologies are

available and if we are using multiple location technology then it become more

crucial to manage them .


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QoSDREAM PROJECT

QoSDREAM aims to provide a middleware platform for developing distributed

multimedia applications. And we will discuss its approach to handling context

information and how this information is made available to the rest of the system.


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ARCHITECTURE

Figure shows the constituents of the QoSDREAM Architecture . It consists of four

major part.


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LOCATION SERVICE

At the lowest level of architecture we have location service and its main functionalities

are

Location service is in charge of gathering location information from specific

location-technologies.

It presents this information to the rest of the system in a location-technologyindependent fashion (uniform way of presenting information).

functionality of location service also include managing and filtering the potentially

large amount of location information that can be generated.


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EVENTMESSAGING SYSTEM

Event messaging system again filters data.

Then it provides information to rest of the system and application .

It distributes event to interested parties . As not every sensor event is useful for each

part of the system.


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MULTIMEDIA SERVICE

The Distributed Multimedia Service [MNCK99] allows applications to construct

distributed multimedia components.

And it also help applications in managing these multimedia application.


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OBJECT DATABASE MANAGER

The Distributed Object Database Management Service provides a means of sharingsystem wide properties such as information about known physical objects. The

information held by the database is largely 'static' (i.e. it is not modified very often),

although some location-specific data may also be stored with it.


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MODELING INFORMATION MANAGEMENT

Within QoSDREAM, applications are presented with a simplified model of the realphysical world. This model contains the following abstractions:

LOCATABLESLOCATABLE

REGION

LOCATORS

INFORMATON

MANAGEMET


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LOCATORS

LOCATABLES

LOCATABLE REGIONS

which represent objects whose locationcan be determined by a given

location-technology. Active badges andBats are examples of Locators.

these represent objects whose locationsneed to be tracked.

Examples include people and equipment.

Locatable must have at least oneassociated locator, so that their location

can be inferred from its locator.

Each locatable will in general have one ormore regions.

These regions define various locationspecific characteristics of Locatable.

For instance in the case of a person, theymay include in addition to the personslocation, their visual and audible fields.


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MANAGEMENT OF LOCATION INROMATION

Our Location Service performs management of location information. Figure 2 depictsthe various abstractions that form this service:


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WORKINGS.

STEP 1

At the lowest level we have Federator objects, these interface with specific locationtechnologies and can detect location information.

The information gathered by Federators is exported through light-weight eventscalled Federator Events. These contain generic information such as the type and idof the federator as well as federator-specific data.

STEP 2 Federator events are also sent to our Spatial Relations Manager (SRM). The SRMs

task is to convert information gathered by Federators into overlapping eventsbetween the regions in our world model.

Before the SRM can reason about the regions and their interactions, LocationModules translate Federator events into regions.

Location Modules are Federator-type-specific, and can be loaded from the databaseby the SRM.

The SRM uses the federator Type field ofFederator Events to determine therequired Location Module.


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CONTINUED..

STEP 3

Once the SRM has obtained updated regions from Location Modules it analysesthem looking for changes in overlaps between regions.

If those are found then the SRM produces what we call Raw Overlap Events.These contain the type of overlap between two regions as well as their previousrelationship.

STEP 4 Applications can register to receive these events, but again these events are too

general for most applications and cannot be filtered.

Instead application register to receive specialized overlap events produced byEvent Adaptors. These types of events can be filtered and relate to higher levelabstractions, such as people and equipment.

Event Adaptors are objects that receive Raw Overlap Events generated by the SRMand can filter and transform these into events that are of interest to applications.

The events generated by Event Adaptors are called Overlap Events, and aretransmitted by QoSDREAMs Message Service.


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The QoSDREAM framework provides an event abstraction that enables

applications to register for events by event type.

Further selection is performed by event filters which the application can

instantiate.

Options for event queuing, communication, fault tolerance, event

persistence, reliability and security will be offered in a future version of the

DREAM framework. QoSDREAM uses events primarily for delivery of contextual information

to applications. The messaging service allows application objects to send

and receive events and is also used by the Location Service to deliver

events generated by Event Adaptors.

Our current implementation of the Messaging Service uses an

implementation of the Cambridge Event Architecture called Herald [SPI00]

as the event delivery system.

Other event delivery systems can be easily added to our Messaging Service

by the implementation of a single interface.


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The Messaging Service facilitates the management of

location information in a number of ways:-

It allows clients to request the delivery of events withouthaving to know anything about the sources of these events.

Similarly event sources do not require any knowledge about

their clients.

The messaging service also allows applications to specify

filters on the events that are sent to it. This coupled with the

location service greatly reduces location-related traffic.

Without the location service and messaging service,

applications would need to monitor all location information

generated by the various underlying location technologies. Messaging Service is itself independent of the event delivery system

used to transfer events from event sources to event clients.


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Our current implementation of the Messaging Service

uses an implementation of the Cambridge Event

Architecture called Herald [SPI00] as the event delivery

system. Other event delivery systems can be easily added to our

Messaging Service by the implementation of a single

interface.


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Experience

A pilot application has been developed for use as a

communications aid, allowing them to locate one

another, establish and participate in audio/visual

conferences. It exploits location information provided by the Active

Badge System deployed in the laboratory.

The Active Lab application registers interest only in

Person Movement events (in order to update its display).Thus in this application, the QoSDREAM location

architecture reduces the event traffic that the application

process.


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CONCLUSION

We have described the approach employed in the QoSDREAM project to themanagement of location events derived from a variety of sources and technologies.

Location events are integrated through the generation of overlap events that areconstructed by geometric analysis according to the requirements of applications,reducing the incoming event traffic to proportions that are manageable by

applications.

QoSDREAM is a software framework that supports the construction of contextaware multimedia applications. For details on other aspects of the QoSDREAMframework see [QDream01].


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THANKS.

Documents

LOCATION INFORMATION MANAGEMENT