Abstract. Today's mobile devices allow end users to get information related to a particular domain based on their current location, such as the fastest route to the nearest drugstore. However, in such LocationBased Services (LBS), richer and more targeted information is desirable. In many applications, end users would like to be notified about relevant events or places to visit in the near future according to their profile. They also do not wish to get the same information many times unless they explicitly ask for it. In this paper, we describe our system, TIP (Tourism Information Provider), which delivers various types of information to mobile devices based on location, time, profile of end users, and their "history", i.e., their accumulated knowledge. The system hinges on a hierarchical semantic geospatial model as well as on an Event Notification System (ENS).
Mobile devices such as personal digital assistants (PDAs) and mobile phones are in widespread use already today and converging to mobile smart phones. They enable the users to access a wide range of services and information without guiding them through their actual demands. Especially during mass events like the Olympic Games 2008 in Beijing -which was initially the context of our work -a large service space is expected to support all mobile visitors, being athletes, journalists, or spectators.Current approaches tackling such problems are location-based (i.e., location-based services), meaning that a user's location is taken into consideration for service provision, and even contextaware, meaning that beyond location other characteristics of a user's environment are taken into account. Such information obviously helps to deliver relevant information at the right time to the mobile users. Going one step further, a situation-aware system abstracts from the context dimensions by translating specific contexts into logical situations (such as being in the car, in a stadium). Even though many context frameworks have been introduced in the past few years, what is usually missing is the notion of characteristic features of contexts which are invariant during certain time intervals. We refer to such features as situations. Knowing the situation end users are in allows the system to better target the information to be delivered to them. This paper presents the main concepts developed for a platform named FLAME2008, which is able to support its mobile users with personalized situation-aware services in push and pull mode.
Event notification services are used in various applications such as digital libraries, stock tickers, traffic control, or facility management. However, to our knowledge, a common semantics of events in event notification services has not been defined so far. In this paper, we propose a parameterized event algebra which describes the semantics of composite events for event notification systems. The parameters serve as a basis for flexible handling of duplicates in both primitive and composite events. ¿¼ AE µ. Events are denoted by lower Latin , while event classes
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