Top-k preferences in high dimensions

Albert Yu, Pankaj K. Agarwal, Jun Yang
2014 2014 IEEE 30th International Conference on Data Engineering  
Given a set of objects O, each with d numeric attributes, a top-k preference scores these objects using a linear combination of their attribute values, where the weight on each attribute reflects the interest in this attribute. Given a query preference q, a top-k query finds the k objects in O with highest scores with respect to q. Given a query object o and a set of preferences Q, a reverse top-k query finds all preferences q ∈ Q for which o becomes one of the top k objects with respect to q.
more » ... revious solutions to these problems are effective only in low dimensions. In this paper, we develop a solution for much higher dimensions (up to high tens), if many preferences exhibit sparsity-i.e., each specifies non-zero weights for only a handful (say 5-7) of attributes (though the subsets of such attributes and their weights can vary greatly). Our idea is to select carefully a set of low-dimensional core subspaces to "cover" the sparse preferences in a workload. These subspaces allow us to index them more effectively than the full-dimensional space. Being multi-dimensional, each subspace covers many possible preferences; furthermore, multiple subspaces can jointly cover a preference, thereby expanding the coverage beyond each subspace's dimensionality. Experimental evaluation validates our solution's effectiveness and advantages over previous solutions.
doi:10.1109/icde.2014.6816697 dblp:conf/icde/YuAY14 fatcat:gojudjqbtzb5vaqoanirogkwnu