Energy-efficient top-k query processing in wireless sensor networks

Abstract

Technological advances have enabled the deployment of largescale sensor networks for environmental monitoring and surveillance purposes. The large volume of data generated by sensors needs to be processed to respond to the users queries. However, efficient processing of queries in sensor networks poses great challenges due to the unique characteristics imposed on sensor networks including slow processing capability, limited storage, and energy-limited batteries, etc. Among various queries, top-k query is one of the fundamental operators in many applications of wireless sensor networks for phenomenon monitoring. In this paper we focus on evaluating top-k queries in an energy-efficient manner such that the network lifetime is maximized. To achieve that, we devise a scalable, filter-based localized evaluation algorithm for top-k query evaluation, which is able to filter out as many unlikely top-k results as possible within the network from transmission. We also conduct extensive experiments by simulations to evaluate the performance of the proposed algorithm on real datasets. The experimental results show that the proposed algorithm outperforms existing algorithms significantly in network lifetime prolongation.

Efficient cluster-based top-k query routing with data replication in MANETs

“…Efficient top-k query processing methods for distributed environments such as P2P networks (Akbarinia et al 2006;Michel et al 2005;Vlachou et al 2008Vlachou et al , 2012 and wireless sensor networks (WSNs) (Chen et al 2010(Chen et al , 2011Jiang et al 2011;Liu et al 2010;Niedermayer et al 2010;Wu et al 2007) have also been proposed. However, P2P networks assume neither packet collisions nor movement of nodes and typically assume that any peers can communicate directly with other peers.…”

Efficient Multidimensional Top-kQuery Processing in Wireless Multihop Networks

“…Many papers [10][11][12][20][21][22] deal with efficient processing of top-queries in wireless sensor networks with the aim of prolonging network life time. An in-network aggregation technique has been proposed in [11].…”

“…However, this approximation technique does not guarantee perfect accuracy of the query result. The authors in [12,20,21] proposed methods which utilize a filtering approach to prune unnecessary data objects. A sink node in the network constructs filters from received data objects and distributes the filters to each sensor node.…”

“…In the case where the number of calculated scores, , whose values are between [ .score, .score] is less than the number of data objects (there exist (⌊ /2⌋ − 1) data objects between ( , ) and ( − ⌊ /2⌋ − 2) data objects between ( , )) existing between ( , ), that is, < (⌊ /2⌋ − 1) + ( − ⌊ /2⌋ − 2) accurately, such nodes estimate the missing data object information at me in [ , ] and ub in ( , ] (lines 14-16 and 18-20). Supplementing the score information which cannot be acquired with respective maximum scores in [ , ] and ( , ] does not estimate the th score of data object in the upstream dataset at less value than the exact value; that is, no false negative Input: , , Output: , , (1) / * Node, , constructs a filter from a query sent by (20) mu data ← mu data ∪ { . , −( + )} (21) Calculate local top-k data from its own data and neighbors' -skyband within search range…”

“…, } and then constructs the filter, . After that, stores all identifiers of cluster-heads (CH ) and their corresponding next nodes (next node ) in its routing AT ← 0 (10) for ∀ ← RoutingTable.entry do (11) if .CH is not included in CL and (12) .next node is within from then (13) AT ← AT ∪ { .CH, .next node} (14) if ̸ = 0 then (15) ← ⟨org, org position, , , , , , , ⟩ (16) Send to nodes included in AT as next node (17) else (18) LeafFlag ← 1 (19) Perform Algorithm 5 (20) if then (21) Reply data whose score is not more than threshold to parent the identifiers of cluster-heads to which the query has been transmitted, so initially CL = 0 in 's query message. (If is a cluster-head, = {org}.)…”