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1. Foundations of LBS

Learning Objectives

  • After completion of the lesson you will be able to identify the components and participants of a given LBS application.
  • You will be able to describe the interaction of the components, which is the processing chain of a service request.
  • Further you will be able to list and explain five types of context awareness.
  • You will be able to list three levels of adaption and give two examples on every level.

Introduction


Mobile phones and the Internet have revolutionized the communication and with it the lifestyle of people. An increasing number of mobile phones and Personal Digital Assistants (PDA) allow people to access the Internet where ever they are and when ever they want. From the Internet they can obtain on one hand information on events (cinema, concerts, parties) and on the other hand information on places (city maps, restaurants, museums, hospitals).

Let us consider the example that somebody wants to take a dinner in a restaurant and is therefore searching a restaurant in the Internet. A useful approach to prevent that one gets as search result every restaurant web-page on the world one could restrict the search by adding further search criteria. A good choice is the city where the mobile user is (position), the actual time (evening) or a special type of restaurant (Chinese or Greek).

Such kind of restaurant search with respect to position and time can be done by use of a Location Based Service (LBS). Thus, one can define that:
A Location Based Service delivering a map of the      environment and the position of the hiker.A Location Based Service delivering a map of the environment and the position of the hiker.
LBS Definition 1:
importantLBS's are information services accessible with mobile devices through the mobile network and utilizing the ability to make use of the location of the mobile device. (Virrantaus et al. 2001)

A similar definition for LBS is given by the international OpenGeospatial Consortium (OGC, 2005):

LBS Definition 2:
importantA wireless-IP service that uses geographic information to serve a mobile user. Any application service that exploits the position of a mobile terminal. (Open Geospatial Consortium 2005)

These definitions describe LBS as an intersection of three technologies (see figure). It is created from New Information and Communication Technologies (NICTS) such as the mobile telecommunication system and hand held devices, from Internet and from Geographic Information Systems (GIS) with spatial databases (Shiode et al. 2004).

LBS as an intersection of    technologiesLBS as an intersection of technologies (Brimicombe 2002)

From a historical point of view location based information are not a new thing which came up with the invention of mobile phones. (2001) emphasize that position specific information is also transported on one hand in a person-to person communication by post-it notes and graffiti. On the other hand methods to locally inform a mass-audience are posters (e.g. of concerts in the town) or simply traffic signs, which submit navigational information. These communication forms are usually one way communications. LBS give the possibility of a two way communication and interaction. Therefore the user tells the service provider his actual context like the kind of information he needs, his preferences and his position. This helps the provider of such location services to deliver information tailored to the user needs.

In the following four subsections we will try to answer the mayor questions which may appear if somebody likes to know what Location Based Services are:



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