The mobile computing advent brings a set of new applications that benefit from the constant need of information, diminishing communication costs and favoring the popularization of mobile devices, to reach an increasing number of users. The mobility characteristic opens a new area for software applications. Associated to the mobility we have the location identification, which turns into a critical attribute, once it allows the development of a great variety of new services and applications. The systems that benefit from the use of that location information are named locationbased systems (LBS); alternatively, these applications are also known as location-aware, context-aware, or adaptive information systems More precisely, we can define LBS as applications that use the location information to supply services, based on this position context, to their users (Kupper, 2005; Schiller & Voisard, 2004). The user location information makes available completely new and innovative service concepts, offering information to the user based on its own context (e.g., climatic information in the region where the user is located), increasing considerably the utility of these services. We know that location- based applications increase the services effectiveness, as they give a customized access to the data based on the user’s preferences and on its actual position. This enhances the personalization content, giving several benefits to users and to the application developers. In our daily life, several activities may use these services, like the emergency call centers, the car navigation services, and even location-based friend finder. We may verify that, beyond the already cited characteristics and benefits, what also gave the LBS applications a growing perspective were the location techniques modernization and the mobile devices popularization, enabling the offer of more precise, objective, and useful information. In Shiode et al. (Shiode, Li, Batty, Longley, & Maguire, 2002), research shows the trend of LBS market and the market potential reserved to this class of applications that, each year, turns out to be more important to the users, becoming the area that dominates the applications for mobile devices. According to Sayed (2005), the forecast annual revenues for location-based services was estimated in US $3.3 billions for United States in 2006/2007, and in US $11.7 billions on the other countries. In summary, we may say that the positional information has the potential to explore the user’s geographical context as one of the most important variables for content and services personalization for mobile devices users.
The processes to manage data in location-based applications are especially challenging, as we need to deal with information as the user is moving from one place to other, in an environment with limited resources and also with heterogeneity. Diverse research areas contribute to ease the process of LBS application development to make possible to use all the spectrum of functionalities that can be implemented through these applications.
Developments in diverse areas such as databases, positioning technology, software engineering, and others, have been made, trying to ease the construction of LBS applications in a way to provide a large spectrum of services in this kind of applications.
Diverse works were proposed dedicated to developing frameworks that provide reuse in the development of LBS applications.
In Wolfson (1999), moving objects databases that store mobile objects location information are considered, especially the location information. The work concentrates on the query and update problems. For the update problem, an information cost model based on the communication cost and information accuracy is proposed.
Large-scale architecture for location services is proposed in Leonhardi and Rothermel (2002). The architecture presents a model of a location service (or generic API), defining the semantics of position queries (position), area queries (range), and proximity queries (nearest neighbor). To be scalable, it defines a distributed and hierarchical organization for the servers.
Key Terms in this Chapter
Location Technology: The set of hardware and software tools that may be used to compute the location of a mobile object.
Location Update Protocol: This is the politic used by the location-based service to maintain the mobile object location information updated in a server.
Framework: A set of software routines that provide a foundation structure for an application. Frameworks take the tedium out of writing an application from scratch.
Wireless Network: A type of network that uses radio waves rather than wires to communicate between nodes.
Location-Based Services: Location-based services refers to a class of applications or services that are based on, or enhanced by, information about the spatial location of a user and/or device.
Middleware: Software that functions as a conversion or translation layer. It is also a consolidator and integrator. any programming that serves to “glue together” or mediate between two separate and often already existing programs.