Department of Computer Science amp Engineering labradorcseeusfedu httpwwwcseeusfedulabrador Outline Location Based Information Systems LBIS LBIS challenges LocationBased Services LBS applications ID: 724255
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Slide1
Introduction
Dr. Miguel A. LabradorDepartment of Computer Science & Engineeringlabrador@csee.usf.eduhttp://www.csee.usf.edu/~labradorSlide2
Outline
Location Based Information Systems (LBIS)LBIS challengesLocation-Based Services (LBS) applicationsLocation provider architecturesSoftware architectureA complete LBS exampleSlide3
Location Based Information Systems
Systems that integrate advances in mobile phones, software development platforms, databases, positioning technology, Geographic Information Systems (GIS), and communicationsAll combined make possible the creation of Location-Based Information Systems (LBIS) and Location-Based Services (LBS)Promise to change the way we live3.25 billion mobile phone users in 2007Half the world’s population
LBS subscribers using GPS-enabled cell phones expected to grow from 12 M in 2006 to 315 M in 201120 M from 500 K in North AmericaSlide4
LBIS Challenges
Many players and technologies involved, and many issues unsolvedDatabases, GIS systems, positioning, applicationsErroneous and variable informationAccuracy of GPS fixes depend on positioning system, user location, weather conditions, interferences, etc.Cellular communication networksWireless transmission problems, such as fading, interferences, disconnections, low bandwidth, etc.
Cell phonesVery resource-constrained device in terms of processing power, storage, and energy capabilitiesOperating systems and interoperabilitySlide5
Location-Based Services (LBS)
An application that provides users with information based on the geographical position of the mobile deviceMain difference from other applications/systemsAvailability of the user’s position in real-timeThis single difference makes a BIG differenceInitial LBS systems were subscription-basedTraffic congestion notifications based on roads selected from a Web site
Received congestion updates about I-75 when on travel in NYC!Slide6
Types of LBS Applications
LBS can be either Reactive (“pull”) or Proactive (“push”)A Reactive LBS application is triggered by the user who, based on his current location, queries the system in search of informationMany examplesFinding restaurants or places of interestObtaining directionsLocating peopleObtaining weather information
Sending emergency notifications to police, insurance companies, roadside assistance companies, etc.Slide7
Types of LBS Applications
In Proactive LBS applications, on the other hand, queries or actions are automatically generated by the LBIS once a predefined set of conditions are metSystem needs to continuously know where you are and evaluate the predefined conditionsMany examples as wellGeofencing, e.g., children outside predefined boundaryFleet management
Real-time traffic congestion notificationsLocation-based advertisementReal-time friend findingProximity-based actuation
Travel assistant device for riding public transportation, tourism, museum guided visits, etcSlide8
Location
In LBIS and LBS applications everything is about LOCATIONImportant to know about different players and techniques used in the provision of location informationA location provider may or may not be the same entity providing the location-based service to the userAccording to who provides the location information, the system can be categorized as network-based, mobile-based, and location provider-basedSlide9
Network-Based Location Provider
Usually the same cellular network carrierCarrier locates the user and stores his location in a database within its networkLBS provider needs to obtain permission and/or pay for obtaining user location informationLBS application needs mechanisms to query the DBPreferred way of cellular carriers
Maintain ownership and control of the location informationAdditional revenuesHave not accelerated the development of LBSCellular networks need to install costly positioning technologies
Carriers may limit the number and frequency of queriesLimiting the developing of some applications, mostly real-time onesApplications need to be aware of which carrier the user belongs toSlide10
Network-Based Location ProviderSlide11
Mobile-Based Location Provider
Mobile device has the capability of obtaining the locationGPS, cell network, bothLocation is sent to the LBS service provider and stored in its database for future reference or processingServer application may or may not send information back to userDepends on application and predefined parameters
Clients are not limited to cellular phonesAny GPS-enabled device with communication capabilityAccelerated rapid development of LBS applicationNeither financial nor technical barriers
Main disadvantage of this method is that it has the potential to flood the network with location updatesDifferent LBS providers may or may not share the locationsA user may be sending same location to more than one LBS providerSlide12
Mobile-Based Location ProviderSlide13
Location Provider-Based
Meant to solve the flooding problem of mobile-based methodIndependent entity collects locations using different methods and make them available to LBS providersOnly business is to provide location informationScalable architecture; perhaps the best architecture for wide deployment of LBSProvisions needed to guarantee fair price and include competitionThere are a few companies that provide location information
Skyhook, Where, Veriplace, Loc-Aid Technologies, othersIn this class, we will use the mobile-based method
GPS-enabled cell phones and network-based technologiesSlide14
Location Provider-Based Slide15
A Complete LBIS Tracking Example
General real-time tracking application with visualizationTracking devices, people, etc.Uses the mobile-based location provider architectureProactive LBS application consisting of the following components:Positioning systemClient deviceTransport network
Main control stationServersStandard and free software and standard protocols as much as possibleSlide16
Hardware
Positioning system GPS and Assisted GPS (A-GPS)Client deviceGPS-enabled cell phone or any device with GPS or embedded positioning systemTransport networkCellular network with data plan (GPRS or similar) or network connectivity using Wi-Fi or any other IP-based networking technology
Main control stationPC connected to the system to control service and visualize data, e.g., set up geofence and Google maps
ServersDatabase, GIS for geocoding and reverse geocoding, application server for processingSlide17
Software
Java platformJava SE for clients and Java ME for resource-constrained devicesSun’s Glassfish as the application serverGoogle ‘s Web Toolkit for visualizationGoogle Maps and Google EarthPostgres, and object-oriented relational databasePostGIS
, Postgres’s add on to support geographic objectsStandard communication protocolsHTTP, TCP, UDPSlide18
A Complete Tracking System ExampleSlide19
Software Architecture
Software architecture is needed in order to Have an organized systemKnow who does what in the system Understand data flowKnow about relationships between componentsKnow protocols and interfaces usedSoftware architecture for the client and for the server
An example follows Used in proactive, mobile-based location provider applications related to transportationSlide20
Software Architecture - ClientSlide21
Software Architecture - ServerSlide22
A Brief Look into the Future
LBS, Human-Centric Sensing, Participatory SensingSlide23
Participatory Sensing