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— Preserving individual privacy when publishing data is a problem that is receiving increasing attention. According to the k-anonymity principle, each release of data must be such that each individual is indistinguishable from at least k − 1 other individuals. In this paper we study the problem of anonymity preserving data publishing in moving objects(More)
The increasing pervasiveness of location-acquisition technologies (GPS, GSM networks, etc.) is leading to the collection of large spatio-temporal datasets and to the opportunity of discovering usable knowledge about movement behaviour, which fosters novel applications and services. In this paper, we move towards this direction and develop an extension of(More)
Spatio-temporal, geo-referenced datasets are growing rapidly, and will be more in the near future, due to both technological and social/commercial reasons. From the data mining viewpoint, spatio-temporal trajectory data introduce new dimensions and, correspondingly , novel issues in performing the analysis tasks. In this paper, we consider the clustering(More)
One of the most common operations in exploration and analysis of various kinds of data is clustering, i.e. discovery and interpretation of groups of objects having similar properties and/or behaviors. In clustering, objects are often treated as points in multi-dimensional space of properties. However, structurally complex objects, such as trajectories of(More)
Agents are small programs that autonomously take actions based on changes in their environment or “state”. Over the last few years, there has been an increasing number of efforts to build agents that can interact and/or collaborate with other agents. In one of these efforts Eiter et al. [1999] have shown how agents may be built on top of legacy(More)
We consider in this paper an extension of Datalog with mechanisms for temporal, nonmonotonic and nondeterministic reasoning, which we refer to as Datalog++. We study its semantics, and show how iterated xpoint and stable model semantics can be combined to the purpose of clarifying the interpretation of Datalog++ programs, and supporting their eecient(More)
The paper investigates the possibilities of using clustering techniques in visual exploration and analysis of large numbers of trajectories, i.e. sequences of time-stamped locations of some moving entities. Trajectories are complex spatio-temporal constructs characterized by diverse non-trivial properties. To assess the degree of (dis)similarity between(More)