Phan Nhat Hai

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One of the objectives of spatio-temporal data mining is to analyze moving object datasets to exploit interesting patterns. Traditionally, existing methods only focus on an unchanged group of moving objects during a time period. Thus, they cannot capture object moving trends which can be very useful for better understanding the natural moving behavior in(More)
Recent improvements in positioning technology has led to a much wider availability of massive moving object data. A crucial task is to find the moving objects that travel together. Usually, they are called spatio-temporal patterns. Due to the emergence of many different kinds of spatio-temporal patterns in recent years, different approaches have been(More)
Recent improvements in positioning technology has led to a much wider availability of massive moving object data. A crucial task is to find the moving objects that travel together. Usually, these object sets are called spatio-temporal patterns. Analyzing such data has been applied in many real world applications, e.g., in ecological study, vehicle control,(More)
Tweets exchanged over the Internet are an important source of information even if their characteristics make them difficult to analyze (e.g., a maximum of 140 characters; noisy data). In this paper, we investigate two different problems. The first one is related to the extraction of representative terms from a set of tweets. More precisely we address the(More)
Recent improvements in positioning technology have led to a much wider availability of massive moving object data. One of the objectives of spatio-temporal data mining is to analyze such datasets to exploit moving objects that travel together. Naturally, the moving objects in a cluster may actually diverge temporarily and congregate at certain timestamps.(More)
Mining trajectories (or moving object patterns) from spatio-temporal data is an active research field. Most of the researches are devoted to extract trajectories that differ in their structure and characteristic in order to capture different object behaviors. The first issue is constituted from the fact that all these methods extract thousand of patterns(More)
Finding similar users is one of the probable applications in social media. The similarity between users can be measured in two different approaches: the semantic similarity and the similarity in terms of social relations. These two approaches can be combined with different weight factors. However, the conventional combination scheme has a critical drawback(More)
Recent improvements in positioning technology has led to a much wider availability of massive moving object data. A crucial task is to find the moving objects that travel together. Usually, they are called spatio-temporal patterns. Due to the emergence of many different kinds of spatio-temporal patterns in recent years, different approaches have been(More)
² M ining gradual patterns plays a crucial role in many real world applications where very large and complex numerical data must be handled, e.g., biological databases, survey databases, data streams or sensor readings. Gradual rules highlight complex order correlations of the form ³7KH PRUHOHVV ; WKHQ WKH PRUHOHVV <´. Such rules have been studied for a(More)
— Most clustering algorithms tend to separate large scale online communities into several meaningful sub-communities by extracting cut points and cut edges. However, these algorithms are not effective on dense and concentrated graphs which do not have any meaningful cut points. Common problems with the previous algorithms are as follows. First, the size of(More)
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