11 Introduction Dr. Miguel A. Labrador Department of Computer Science & Engineering

2 Copyright© Dr. Miguel A. Labrador 2 2 Outline Location Based Information Systems (LBIS) LBIS challenges Location-Based Services (LBS) applications Location provider architectures Software architecture A complete LBS example

3 Copyright© Dr. Miguel A. Labrador 3 3 Location Based Information Systems Systems that integrate advances in mobile phones, software development platforms, databases, positioning technology, Geographic Information Systems (GIS), and communications All combined make possible the creation of Location-Based Information Systems (LBIS) and Location-Based Services (LBS) –Promise to change the way we live 3.25 billion mobile phone users in 2007 –Half the world’s population LBS subscribers using GPS-enabled cell phones expected to grow from 12 M in 2006 to 315 M in 2011 –20 M from 500 K in North America

4 Copyright© Dr. Miguel A. Labrador 4 4 LBIS Challenges Many players and technologies involved, and many issues unsolved –Databases, GIS systems, positioning, applications Erroneous and variable information –Accuracy of GPS fixes depend on positioning system, user location, weather conditions, interferences, etc. Cellular communication networks –Wireless transmission problems, such as fading, interferences, disconnections, low bandwidth, etc. Cell phones –Very resource-constrained device in terms of processing power, storage, and energy capabilities Operating systems and interoperability

5 Copyright© Dr. Miguel A. Labrador 5 5 Location-Based Services (LBS) An application that provides users with information based on the geographical position of the mobile device Main difference from other applications/systems –Availability of the user’s position in real-time –This single difference makes a BIG difference Initial LBS systems were subscription-based –Traffic congestion notifications based on roads selected from a Web site –Received congestion updates about I-75 when on travel in NYC!

6 Copyright© Dr. Miguel A. Labrador 6 6 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 information Many examples –Finding restaurants or places of interest –Obtaining directions –Locating people –Obtaining weather information –Sending emergency notifications to police, insurance companies, roadside assistance companies, etc.

7 Copyright© Dr. Miguel A. Labrador 7 7 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 met System needs to continuously know where you are and evaluate the predefined conditions Many examples as well –Geofencing, e.g., children outside predefined boundary –Fleet management –Real-time traffic congestion notifications –Location-based advertisement –Real-time friend finding –Proximity-based actuation –Travel assistant device for riding public transportation, tourism, museum guided visits, etc

8 Copyright© Dr. Miguel A. Labrador 8 8 Location In LBIS and LBS applications everything is about LOCATION Important to know about different players and techniques used in the provision of location information A location provider may or may not be the same entity providing the location-based service to the user According to who provides the location information, the system can be categorized as network-based, mobile-based, and location provider-based

9 Copyright© Dr. Miguel A. Labrador 9 9 Network-Based Location Provider Usually the same cellular network carrier Carrier locates the user and stores his location in a database within its network LBS provider needs to obtain permission and/or pay for obtaining user location information LBS application needs mechanisms to query the DB Preferred way of cellular carriers –Maintain ownership and control of the location information –Additional revenues Have not accelerated the development of LBS –Cellular networks need to install costly positioning technologies –Carriers may limit the number and frequency of queries Limiting the developing of some applications, mostly real-time ones –Applications need to be aware of which carrier the user belongs to

10 Copyright© Dr. Miguel A. Labrador 10 Copyright© Dr. Miguel A. Labrador 10 Network-Based Location Provider

11 Copyright© Dr. Miguel A. Labrador 11 Copyright© Dr. Miguel A. Labrador 11 Mobile-Based Location Provider Mobile device has the capability of obtaining the location –GPS, cell network, both Location is sent to the LBS service provider and stored in its database for future reference or processing Server application may or may not send information back to user –Depends on application and predefined parameters Clients are not limited to cellular phones –Any GPS-enabled device with communication capability Accelerated rapid development of LBS application –Neither financial nor technical barriers Main disadvantage of this method is that it has the potential to flood the network with location updates –Different LBS providers may or may not share the locations –A user may be sending same location to more than one LBS provider

12 Copyright© Dr. Miguel A. Labrador 12 Copyright© Dr. Miguel A. Labrador 12 Mobile-Based Location Provider

13 Copyright© Dr. Miguel A. Labrador 13 Copyright© Dr. Miguel A. Labrador 13 Location Provider-Based Meant to solve the flooding problem of mobile-based method Independent entity collects locations using different methods and make them available to LBS providers Only business is to provide location information Scalable architecture; perhaps the best architecture for wide deployment of LBS –Provisions needed to guarantee fair price and include competition There are a few companies that provide location information –Skyhook, Where, Veriplace, Loc-Aid Technologies, others –In this class, we will use the mobile-based method GPS-enabled cell phones and network-based technologies

14 Copyright© Dr. Miguel A. Labrador 14 Copyright© Dr. Miguel A. Labrador 14 Location Provider-Based

15 Copyright© Dr. Miguel A. Labrador 15 Copyright© Dr. Miguel A. Labrador 15 A Complete LBIS Tracking Example General real-time tracking application with visualization –Tracking devices, people, etc. Uses the mobile-based location provider architecture Proactive LBS application consisting of the following components: –Positioning system –Client device –Transport network –Main control station –Servers Standard and free software and standard protocols as much as possible

16 Copyright© Dr. Miguel A. Labrador 16 Copyright© Dr. Miguel A. Labrador 16 Hardware Positioning system –GPS and Assisted GPS (A-GPS) Client device –GPS-enabled cell phone or any device with GPS or embedded positioning system Transport network –Cellular network with data plan (GPRS or similar) or network connectivity using Wi-Fi or any other IP-based networking technology Main control station –PC connected to the system to control service and visualize data, e.g., set up geofence and Google maps Servers –Database, GIS for geocoding and reverse geocoding, application server for processing

17 Copyright© Dr. Miguel A. Labrador 17 Copyright© Dr. Miguel A. Labrador 17 Software Java platform –Java SE for clients and Java ME for resource-constrained devices Sun’s Glassfish as the application server Google ‘s Web Toolkit for visualization –Google Maps and Google Earth Postgres, and object-oriented relational database PostGIS, Postgres’s add on to support geographic objects Standard communication protocols –HTTP, TCP, UDP

18 Copyright© Dr. Miguel A. Labrador 18 Copyright© Dr. Miguel A. Labrador 18 A Complete Tracking System Example

19 Copyright© Dr. Miguel A. Labrador 19 Copyright© Dr. Miguel A. Labrador 19 Software Architecture Software architecture is needed in order to –Have an organized system –Know who does what in the system –Understand data flow –Know about relationships between components –Know protocols and interfaces used Software architecture for the client and for the server –An example follows –Used in proactive, mobile-based location provider applications related to transportation

20 Copyright© Dr. Miguel A. Labrador 20 Copyright© Dr. Miguel A. Labrador 20 Software Architecture - Client

21 Copyright© Dr. Miguel A. Labrador 21 Copyright© Dr. Miguel A. Labrador 21 Software Architecture - Server

22 Copyright© Dr. Miguel A. Labrador 22 Copyright© Dr. Miguel A. Labrador 22 A Brief Look into the Future LBS, Human-Centric Sensing, Participatory Sensing

23 Copyright© Dr. Miguel A. Labrador 23 Copyright© Dr. Miguel A. Labrador 23 Participatory Sensing