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An important consideration in similarity-based retrieval of moving object trajectories is the definition of a distance function. The existing distance functions are usually sensitive to noise, shifts and scaling of data that commonly occur due to sensor failures, errors in detection techniques, disturbance signals, and different sampling rates. Cleaning(More)
Traditional databases store sets of relatively static records with no pre-defined notion of time, unless timestamp attributes are explicitly added. While this model adequately represents commercial catalogues or repositories of personal information, many current and emerging applications require support for on-line analysis of rapidly changing data streams.(More)
The k-core of a graph is the largest subgraph in which every vertex is connected to at least k other vertices within the subgraph. Core decomposition finds the k-core of the graph for every possible k. Past studies have shown important applications of core decomposition such as in the study of the properties of large networks (e.g., sustainability,(More)
XML support is being added to existing database management systems (DBMSs) and native XML systems are being developed both in industry and in academia. The individual performance characteristics of these approaches as well as the relative performance of various systems is an ongoing concern. In this paper we discuss the XBench XML benchmark and report on(More)
Predicting the next request of a user as she visits Web pages has gained importance as Web-based activity increases. Markov models and their variations, or models based on sequence mining have been found well suited for this problem. However, higher order Markov models are extremely complicated due to their large number of states whereas lower order Markov(More)
In this paper we experimentally study the performance of main-memory, parallel, multi-core join algorithms, focusing on sort-merge and (radix-)hash join. The relative performance of these two join approaches have been a topic of discussion for a long time. With the advent of modern multi-core architectures, it has been argued that sort-merge join is now a(More)
The schema of a database system consists of the constructs that model the entities of data. Schema evolution is the timely change of the schema and the consistent management of these changes. Dynamic schema evolution (DSE) is the management of schema changes while a database management system is in operation. DSE is a necessary facility of objectbase(More)
Bichromatic reverse nearest neighbor (BRNN) has been extensively studied in spatial database literature. In this paper , we study a related problem called MaxBRNN: find an optimal region that maximizes the size of BRNNs. Such a problem has many real life applications, including the problem of finding a new server point that attracts as many customers as(More)