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Database users may be frustrated by no answers returned when they pose a query on the database. In this paper, we study the problem of relaxing queries on RDF databases in order to acquire approximate answers. We address two problems in efficient query relaxation. First, to ensure the quality of answers, we compute the similarities between relaxed queries(More)
The explosive growth of 3G services seriously challenges the business and operating support systems of telecommunication operators, especially the processing capacity of charging and billing systems. One of the solutions to make service more efficient and smooth, is the support of scalable, reliable, and high-performance clustered server architecture. Based(More)
The emergence of new data services in 3G networks is driving the support of advanced content-based billing mechanisms whose unique characteristics require that the OCS (online charging system) provide relative differentiated services based on different contents. The OCS can be modeled by the PDD (proportional delay differentiation) structure and it aims to(More)
Query relaxation is an important problem for querying RDF data flexibly. The previous work mainly uses ontology information for relaxing user queries. The ranking models proposed, however, are either non-quantifiable or imprecise. Furthermore, the recommended relaxed queries may return no results. In this paper, we aim to solve these problems by proposing a(More)
The traditional RR (Round Robin) task scheduling algorithms and real-time feedback control models are hard to satisfy the QoS changing demands for non-real-time tasks on data value-added services systems. An adaptive model of task scheduling is proposed in this paper based on the IDP (integrated data value-added services platform) project. The model(More)
The stabilization problem and the design method of a parameterized controller for a class of uncertain nonlinear multi-time delays systems described in Takagi-Sugeno fuzzy models were concentrated on. The sufficient conditions for the existence of the stable fuzzy controller by state feedback were deduced in terms of Lyapunov stability theory. A convex(More)