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The paradigm of Content-based retrieval (CBR) with query-by-example (QBE) has been prevailing in multimedia applications and systems. While the CRB/QBE approach is easy to use from the end-user's perspective, it is not always possible for a user to prepare/have a suitable "example" in hand; besides, the lack of semantics inherent to this approach may cause strange things to happen (e.g.,...
Reverse nearest neighbor (RNN) queries have a broad application base such as decision support, profile-based marketing, resource allocation, data mining, etc. Previous work on RNN search does not take obstacles into consideration. In the real world, however, there are many physical obstacles (e.g., buildings, blindages, etc.), and their presence may affect the visibility/distance between two objects...
This paper analyses three existing methods of WSN data storage. Based on disadvantage of data-centric storage(DCS), the shortest path first of DCS(SPF-DCS) is present. Compared to DCS, the advantage of this method is that home node finds only one node as its own replica node. SPF-DCS can reduce communication between home node and other nodes, decrease the power consumption of node and prolong lifetime...
This paper considers a multi-query optimization issue for distributed similarity query processing, which attempts to exploit the dependencies in the derivation of a query evaluation plan. To the best of our knowledge, this is the first work investigating a multi- query optimization technique for distributed similarity query processing (MDSQ). Four steps are incorporated in our MDSQ algorithm. First...
Given a set of trajectories D, a query object (point or trajectory) q, and a query interval T, a mutual (i.e., symmetric) nearest neighbor (MNN) query over trajectories finds from D within T, the set of trajectories that are among the k1 nearest neighbors (NNs) of q, and meanwhile, have q as one of their k2 NNs. This type of queries considers proximity of q to the trajectories and the proximity of...
Given two sets DA and DB of multidimensional objects, a spatial region R, and a critical distance dc, an optimal-nearest- neighbor (ONN) query retrieves outside R, the object in DB with maximum optimality. Let CAR (Sp,p) be the cardinality of the subset Sp of objects in DA which locate within R and are enclosed by the vicinity circle centered at p with radius dc. Then, an object o is said to be better...
This paper proposes a novel data-grid-based k nearest neighbor query over large Chinese calligraphic character databases, which can significantly speed up the retrieval efficiency. Three steps are made. Firstly, when a user submits a query request to a query node, a process of character set reduction is performed using iDistance index in different data nodes, followed by sending the candidate characters...
The OLAP (on-line analytical processing) queries are ad hoc, complex aggregation queries on massive data set. How to effectively aggregate the query data becomes the key issue for OLAP query evaluation. To solve this problem, a novel grouping aggregation algorithm, DHEGA(grouping aggregation based on the dimension hierarchical encoding), is proposed in this paper. It utilizes the fairly short DHE(dimension...
Data warehouses contain a vast amount of data, often from different sources. In order to support complex queries of various decision support systems, we need to store materialized views of data. These views represent integrated data based on complex aggregate queries, and should be available consistently and instantaneously, which would not be possible if those queries had to be invoked each time...
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