Multidimensional range queries on hierarchical Voronoi overlays (original) (raw)

Hivory: Range Queries on Hierarchical Voronoi Overlays

Peer-to-Peer …, 2010

The problem of defining a support for multidimensional range queries on P2P overlays is currently an active field of research. Several approaches based on the extension of the basic functionalities offered by Distributed Hash Tables have been recently proposed. The main drawback of these approaches is that the locality required for the resolution of a range query cannot be guaranteed by uniform hashing. On the other way, locality preserving hashing functions do not guarantee a good level of load balancing. This paper presents Hivory, a P2P overlay based on a Voronoi tessellation defined by the objects published by peers. Each object is mapped to a site of the Voronoi tessellation and the corresponding Delaunay Triangulation defines the P2P overlay. A hierarchy of Voronoi diagrams is defined by exploiting clusters of objects paired with the same site of the Voronoi diagram. A new Voronoi diagram including the peers of the cluster is created so that the query resolution may be refined by a top down visit of the Voronoi hierarchy. The paper presents the proposed solution, analyses its complexity, and provides a set of experimental results.

Voraque: Range queries on voronoi overlays

… , 2008. ISCC 2008. IEEE …, 2008

This paper presents VoRaQue, a software layer supporting range queries on Voronoi P2P overlays. VoRaQue maps data in a 2-dimensional space. The P2P overlay is defined by links connecting nodes that are close in the 2-dimensional space and by a set of long-range links which guarantee a polylogarithmic routing. When a query is submitted, VoRaQue finds out a node belonging to the region defined by the query. A multicast spanning tree covering that region is then built by applying compass routing, a distributed protocol to embed a spanning tree into a Delaunay Triangulation. The paper presents the basic VoRaQue protocol, then introduces a set of optimizations and finally presents some experimental results.

Voronoi-based range and continuous range query processing in mobile databases

Journal of Computer and System Sciences, 2011

With the wide availability of mobile devices (smart phones, iPhones, etc.), mobile locationbased queries are increasingly in demand. One of the most frequent queries is range search which returns objects of interest within a pre-defined area. Most of the existing methods are based on the road network expansion method -expanding all nodes (intersections and objects) and computing the distance of each node to the query point. Since road networks are extremely complex, node expansion approaches are inefficient. In this paper, we propose a method, Voronoi Range Search (VRS) based on the Voronoi diagram, to process range search queries efficiently and accurately by partitioning the road networks to some special polygons. Then we further propose Voronoi Continuous Range (VCR) to satisfy the requirement for continuous range search queries (moving queries) based on VRS. Our empirical experiments show that VRS and VCR surpass all their rivals for both static and moving queries.

Multidimensional range queries in sensor networks

2003

In many sensor networks, data or events are named by attributes. Many of these attributes have scalar values, so one natural way to query events of interest is to use a multidimensional range query. An example is: "List all events whose temperature lies between 50 • and 60 • , and whose light levels lie between 10 and 15." Such queries are useful for correlating events occurring within the network.

Voronoi trees for hierarchical in-network data and space abstractions in wireless sensor networks

2013

We address the problem of spatial queries in Wireless Sensor Networks (WSN) via hybrid overlays, where the data values may correspond to different physical phenomena and sensors may be correlated with spatial constraints. We show how hierarchical data and space abstractions can be used to represent Voronoi Cell based partitions of the sensing field and use Voronoi Trees to efficiently map the hierarchical abstractions for energy-efficient processing. The proposed scheme is simulated on the SidNET, a JiST/SWANS based sensor network simulation platform. The performance results show significant advantages in terms of accurate field representation at different levels of the tree hierarchy with a trade-off in query processing delay.

Q-tree: a multi-attribute based range query solution for tele-immersive framework

2009 29th IEEE …, 2009

Users and administrators of large distributed systems are frequently in need of monitoring and management of its various components, data items and resources. Though there exist several distributed query and aggregation systems, the clustered structure of tele-immersive interactive frameworks and their time-sensitive nature and application requirements represent a new class of systems which poses different challenges on this distributed search. Multi-attribute composite range queries are one of the key features in this class. Queries are given in high level descriptions and then transformed into multi-attribute composite range queries. Designing such a query engine with minimum traffic overhead, low service latency, and with static and dynamic nature of large datasets, is a challenging task. In this paper, we propose a general multi-attribute based range query framework, Q-Tree, that provides efficient support for this class of systems. In order to serve efficient queries, Q-Tree builds a single topology-aware tree overlay by connecting the participating nodes in a bottom-up approach, and assigns range intervals on each node in a hierarchical manner. We show the relative strength of Q-Tree by analytically comparing it against P-Tree, P-Ring, Skip-Graph and Chord. With fine-grained load balancing and overlay maintenance, our simulations with PlanetLab traces show that our approach can answer complex queries within a fraction of a second.

VoroNet: A scalable object network based on Voronoi tessellations

2007 IEEE International Parallel and Distributed Processing Symposium, 2007

In this paper, we propose the design of VoroNet, an objectbased peer to peer overlay network relying on Voronoi tessellations, along with its theoretical analysis and experimental evaluation. VoroNet differs from previous overlay networks in that peers are application objects themselves and get identifiers reflecting the semantics of the application instead of relying on hashing functions. This enables a scalable support for efficient search in large collections of data. In VoroNet, objects are organized in an attribute space according to a Voronoi diagram. VoroNet is inspired from the Kleinberg's small-world model where each peer gets connected to close neighbours and maintains an additional pointer to a long-range neighbour. VoroNet improves upon the original proposal as it deals with general object topologies and therefore copes with skewed data distributions. We show that VoroNet can be built and maintained in a fully decentralized way. The theoretical analysis of the system proves that routing in VoroNet can be achieved in a poly-logarithmic number of hops in the size of the system. The analysis is fully confirmed by our experimental evaluation by simulation.

Peer to Peer Multidimensional Overlays: Approximating Complex Structures

Lecture Notes in Computer Science, 2007

Peer to peer overlay networks have proven to be a good support for storing and retrieving data in a fully decentralized way. A sound approach is to structure them in such a way that they reflect the structure of the application. Peers represent objects of the application so that neighbours in the peer to peer network are objects having similar characteristics from the application's point of view. Such structured peer to peer overlay networks provide a natural support for range queries. While some complex structures such as a Voronoï tessellation, where each peer is associated to a cell in the space, are clearly relevant to structure the objects, the associated cost to compute and maintain these structures is usually extremely high for dimensions larger than 2.

Voronoi-based reverse nearest neighbor query processing on spatial networks

Multimedia Systems, 2009

The use of Voronoi diagram has traditionally been applied to computational geometry and multimedia problems. In this paper, we will show how Voronoi diagram can be applied to spatial query processing, and in particular to Reverse Nearest Neighbor (RNN) queries. Spatial and geographical query processing, in general, and RNN in particular, are becoming more important, as online maps are now