Adaptive nearest neighbor queries in travel time networks. Aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Approximate aggregate nearest neighbor queries on road. Today, in the era of ubiquitous mobile computing, this is a highly pertinent query. Aggregate nearest neighbor ann query returns a common interesting data object that minimizes an aggregate distance for multiple query points. Aggregate nearest neighbor queries in road networks. We study the aggregate keyword nearest neighbor aknn queries, finding the poi that has the smallest aggregate distance and covers all query keywords.
Consider, for example, several users at specific locations query points that want to find the restaurant data point, which leads to the minimum sum of distances that they have to travel in. On the one hand, we would like to develop similar incremental algorithms using the road network distance instead of 92 geoinformatica 20 17. Finally, we present experimental results obtained with the implementation of our algorithms. Introduction nearest neighbor query is one of the fundamental issues in spatial database research area. Continuous nearest neighbor monitoring in road networks k mouratidis, ml yiu, d papadias, n mamoulis proceedings of the 32nd international conference on very large data bases, 4354, 2006. While traditional nearest neighbor queries aim to find the k nearest objects to only one certain point, the aggregate k nearest neighbor queries aimtofindthek nearest objects to a set of multiple points.
While euclidean distance has been used as a heuristic to search for the closest pois by their road network distance, its efficacy has not been thoroughly. Pdf on the computation of the optimal connecting points in. We formalize reverse spatial and textual k nearest neighbor rstknn queries on road networks, and identify the problem of rstknn retrieval. Request pdf aggregate k nearest neighbors queries in timedependent road networks in this paper we present an algorithm for processing aggregate nearest neighbor queries in timedependent road.
Consider, for example, several users at specific locations query points that want to find the restaurant data point, which leads to the. Request pdf merged aggregate nearest neighbor query processing in road networks aggregate nearest neighbor query, which returns a common interesting point that minimizes the aggregate distance. Citeseerx aggregate nearest neighbor queries in road networks. Given a set of data points p, a set of query points q, and a userdefined flexibility parameter. Yuanko huang department of maritime information and technology national kaohsiung university of science and technology, taiwan email. Aggregate knearest neighbors queries in timedependent. Aggregate nearest neighbor queries in road networks man lung yiu, nikos mamoulis, and dimitris papadias abstract aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Fast optimal aggregate point search for a merged set on road. They are expected to return a data point or a set of data points poi or points. The flexible aggregate nearest neighbor fann problem further generalizes ann by introducing an extra flexibility.
In order to verify the knn question result on a road network, a naive answer would be to come back the full road network and the purpose of interest poi dataset. All existing methods, however, assume the euclidean distance metric. Path nearest neighbor, road networks, spatial databases 1. Aggregate keyword nearest neighbor queries on road networks. Flexible aggregate nearest neighbor queries in road.
Merged aggregate nearest neighbor query processing in road. Efficient aggregate farthest neighbour query processing on road. During backtracking to the upper level node n 1, the algorithm prunes entries whose mindist is equal to or larger than the distance best distofthe nearest neigh bor already retrieved. This pa per concerns active, ordered knearest neighbor queries for query and data objects that are moving in road networks. While related to the shortest path problem in many ways, the knn problem on road networks introduces new. Group nearest compact poi set queries in road networks. During backtracking to the upper level node n 1, the algorithm prunes entries whose mindist is equal to or larger than the distance best distofthe nearest neighbor already. There are several existing network nearest neighbor query processing methods in the literature, such as the network expansion based methods23,24, solution based methods2628 and hierarchical road networks based methods25. Pdf aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points find, read and. Continuous nearest neighbor monitoring in road networks. Aggregate nearest neighbor ann query has been studied in both the euclidean space and road networks. Efficient reverse spatial and textual k nearest neighbor.
Aggregate nearest neighbor queries in road networks article pdf available in ieee transactions on knowledge and data engineering 176. Pdf aggregate nearest neighbor queries in road networks. Nearest neighbor queries in road networks citeseerx. To the best of our knowledge, this is the first work on rstknn queries on road networks. K aggregate nearest neighbor queries in spatial databases. As an exte nsion of nn queries in the euclidean space, papadias et al. Aggregate nearest neighbor queries in spatial databases 533 fig. Continuous aggregate nearest neighbor queries user personal. We denote this query as the flexible aggregate nearest neighbor in road networks fannr. In order to verify the knn query result on a road network, a naive solution would be to return the whole road network and the point of interest poi dataset to the client to show correctness and completeness of the result. In this paper, we propose a novel approach to efficiently process ann queries in road networks.
On efficient aggregate nearest neighbor query processing in. Aggregate nearest neighbor queries in road networks ieee xplore. Evaluating k nearest neighbor query on road networks with no. This problem has been investigated for both spatial data that uses euclidean distances 29 and for road networks 36 where the distance between two points is. Pdf aggregate nearest neighbor queries return a point with a minimum net distance from a set of query points. Processing locationbased aggregate queries in road networks. Due to their popularity and importance, knearest neighbor knn queries, which. We describe several pruning methods to prune nonpromising objects at a low cost. Aggregate nearest neighbor queries in spatial databases. Many variants of nearest neighbor search are studied as well, like aggregate k nn monitoring 16, trip planning. Efficient aggregate farthest neighbour query processing on road networks. Abstracta krange nearest neighbor or krnn for short query in road networks.
Aggregate nearest neighbor queries in road networks man lung yiu, nikos mamoulis, and dimitris papadias abstractaggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Aggregate nearest neighbor queries in road networks core. Throughout this paper, however, we always name this kind of query with aggregates as gnn, unless otherwise specified. To answer our query efficiently, we first develop a dualgranularity dg indexing schema. Authentication of k nearest neighbor query on road networks. Voronoibased aggregate nearest neighbor query processing in. Aggregate knearest neighbors queries in timedependent road. Papadias, aggregate nearest neighbor queries in road networks, ieee trans.
In particular, we first continuously compute the nearest neighbors nns for each query point in. Monitoring path nearest neighbor in road networks school of. On efficient aggregate nearest neighbor query processing in road. Abstractaggregate nearest neighbor ann query has been studied in both the euclidean space and road networks. Aggregate keyword nearest neighbor queries on road.
The trail from the question purpose to every k nearestneighbor result is the valid shortest path on the network. In this paper, we propose an efficient approach to tackle ann queries in road networks. Nevertheless, existing methods on ann query are either inapplicable or inefficient when applied to the aknn query. The classic method without privacy is the network voronoi nearest neighbor based solution which is proposed by. In that sense, the query answer to the aggregate k nearest neighbor query needs to be defined through an. Gpubased computation of distance functions on road networks. An aggregate nearest neighbor query retrieves the data points with the smallest sum of distances to all query points in a query group. Aggregate nearest neighbor queries aggregate nearest neighbor ann queries are also called group nearest neighbor queries gnn so we will use these names interchangeably hereafter. An aggregate nearest neighbor ann query returns a point of interest poi that minimizes an aggregate function for multiple query points. Citeseerx aggregate nearest neighbor queries in road. Flexible aggregate nearest neighbor queries in road networks. Apart from the above applications in lbsns, knnta queries are useful in many other applications in urban computing 32 where the spatial distance and a temporal aggregate are considered simultaneously, such as locationbased mobile advertising and social.
Continuous aggregate nearest neighbor queries, geoinformatica. In this paper we consider a set of travelers, starting from likely different locations towards a common destination within a road network, and propose solutions to find the optimal connecting points for them. Consider, for example, several users at specific locations query points that want to find the restaurant data point, which leads to the minimum sum of distances that they have to travel in order to meet. A k nearest neighbor knn query on road networks retrieves the k closest points of interest pois by their network distances from a given location. Abstract aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Note that, gnn query with aggregate distance function is also called aggregate nearest neighbor ann query in 18. Article pdf available in ieee transactions on knowledge and data engineering 176. Dec 27, 2011 as for future work, we will investigate the continuous aggregate nearest neighbor queries on moving objects in road networks. Abstractaggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. As applications, we provide algorithms for computing discrete order k network voronoi diagrams and for approximately solving k nearest neighbor queries and aggregate k nearest neighbor queries on road networks. Aggregate nearest neighbor queries in road networks ieee. Many variants of nearest neighbor search are studied as well, like aggregate knn monitoring 16, trip planning. On topk weighted sum aggregate nearest and farthest. A connecting point is a vertex of the network where a subset of the travelers meet and continue traveling together towards the next connecting point or the destination.