1,721,188 research outputs found
Histogram-based clustering of multiple data streams
No full textThis paper introduces a strategy for clustering online multiple data streams. We assume that several sources are used for recording, over time, data about some physical phenomena. Each source provides repeated measurements at a very high frequency so that it is not possible to store the whole amount of data into some easy-to-access media, but data are available only in batches. Our aim is to discover a partition of the sources (e.g. sensors) into homogeneous clusters, analysing the incoming streams of data. The proposed strategy is based on processing the incoming data batches independently, through an initial summarization of the data batches by histograms and, then, by means of a local clustering performed on the histograms which provides a further data summarization. To keep track of the data proximities among the data streams over time, we use local clustering outputs for updating a proximity matrix. The final partitioning of the streams is obtained by a clustering based on such proximity matrix. Through an application on real and simulated data, we show the effectiveness of our strategy in finding homogeneous groups of sources of data streams
La Medicina del Lavoro e l’errore professionale: prevenire gli errori nell’attività di sorveglianza sanitaria
No full textUna strategia di imputazione per mancate risposte in questionari strutturati come oggetti simbolici
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Symbolic Interpretation in a Clustering Strategy on Multiattribute Preference Data
No full textThis paper deals with the construction of a judge typology in the framework of multiattribute preference data analysis
Anthropogenic-driven changes in the coastal zone of the Campania region (southern Italy)
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