Steven Schockaert

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We present a two-step approach to estimate where a given photo or video was taken, using only the tags that a user has assigned to it. In the first step, a language modeling approach is adopted to find the area which most likely contains the geographic location of the resource. In the subsequent second step, a precise location is determined within the area(More)
Although the region connection calculus (RCC) offers an appealing framework for modelling topological relations, its application in real–world scenarios is hampered when spatial phenomena are affected by vagueness. To cope with this, we present a generalization of the RCC based on fuzzy set theory, and discuss how reasoning tasks such as satisfiability and(More)
When the time span of an event is imprecise, it can be represented by a fuzzy set, called a fuzzy time interval. In this paper, we propose a framework to represent, compute, and reason about temporal relationships between such events. Since our model is based on fuzzy orderings of time points, it is not only suitable to express precise relationships between(More)
Geographic information retrieval (GIR) systems allow users to specify a geographic context, in addition to a more traditional query, enabling the system to pinpoint interesting search results whose relevancy is location-dependent. In particular local search services have become a widely used mechanism to find businesses, such as hotels, restaurants, and(More)
The task of automatically estimating the location of web resources is of central importance in location-based services on the Web. Much attention has been focused on Flickr photos and videos, for which it was found that language modeling approaches are particularly suitable. In particular, state-of-the art systems for georeferencing Flickr photos tend to(More)
Algorithms for clustering Web search results have to be efficient and robust. Furthermore they must be able to cluster a data set without using any kind of a priori information, such as the required number of clusters. Clustering algorithms inspired by the behavior of real ants generally meet these requirements. In this article we propose a novel approach(More)
Various intelligent systems rely heavily on formalisms for spatial representation and reasoning. However, it is widely recognized that real-world regions are seldom characterized by a precisely defined boundary. This paper proposes a generalization of the region connection calculus (RCC) which allows to define spatial relations between vague regions. To(More)
Topological relations between geographic regions are of interest in many applications. When the exact boundaries of regions are not available, such relations can be established by analysing natural language information from Web documents. In particular, we demonstrate how redundancy-based techniques can be used to acquire containment and adjacency(More)
Generalized possibilistic logic (GPL) is a logic for reasoning about the revealed beliefs of another agent. It is a two-tier propositional logic, in which propositional formulas are encapsulated by modal operators that are interpreted in terms of uncertainty measures from possibility theory. Models of a GPL theory represent weighted epistemic states and are(More)
Although it is well-known that every satisfiable formula in Łukasiewicz’ infinite-valued logic $\mathcal{L}_{\infty}$ can be satisfied in some finite-valued logic, practical methods for finding an appropriate number of truth degrees do currently not exist. Extending upon earlier results by Aguzzoli et al., which only take the total number of variable(More)