Results 1 
7 of
7
The quadtree and related hierarchical data structures
 ACM Computing Surveys
, 1984
"... A tutorial survey is presented of the quadtree and related hierarchical data structures. They are based on the principle of recursive decomposition. The emphasis is on the representation of data used in applications in image processing, computer graphics, geographic information systems, and robotics ..."
Abstract

Cited by 423 (11 self)
 Add to MetaCart
A tutorial survey is presented of the quadtree and related hierarchical data structures. They are based on the principle of recursive decomposition. The emphasis is on the representation of data used in applications in image processing, computer graphics, geographic information systems, and robotics. There is a greater emphasis on region data (i.e., twodimensional shapes) and to a lesser extent on point, curvilinear, and threedimensional data. A number of operations in which such data structures find use are examined in greater detail.
Dynamic Trees and Dynamic Point Location
 In Proc. 23rd Annu. ACM Sympos. Theory Comput
, 1991
"... This paper describes new methods for maintaining a pointlocation data structure for a dynamicallychanging monotone subdivision S. The main approach is based on the maintenance of two interlaced spanning trees, one for S and one for the graphtheoretic planar dual of S. Queries are answered by using ..."
Abstract

Cited by 43 (9 self)
 Add to MetaCart
This paper describes new methods for maintaining a pointlocation data structure for a dynamicallychanging monotone subdivision S. The main approach is based on the maintenance of two interlaced spanning trees, one for S and one for the graphtheoretic planar dual of S. Queries are answered by using a centroid decomposition of the dual tree to drive searches in the primal tree. These trees are maintained via the linkcut trees structure of Sleator and Tarjan, leading to a scheme that achieves vertex insertion/deletion in O(log n) time, insertion/deletion of kedge monotone chains in O(log n + k) time, and answers queries in O(log 2 n) time, with O(n) space, where n is the current size of subdivision S. The techniques described also allow for the dual operations expand and contract to be implemented in O(log n) time, leading to an improved method for spatial pointlocation in a 3dimensional convex subdivision. In addition, the interlacedtree approach is applied to online pointlo...
Optimal External Memory Interval Management
, 2002
"... In this paper we present the external interval tree, an optimal external memory data structure for answering stabbing queries on a set of dynamically maintained intervals. The external interval tree can be used in an optimal solution to the dynamic interval management problem, which is a central pro ..."
Abstract

Cited by 31 (6 self)
 Add to MetaCart
In this paper we present the external interval tree, an optimal external memory data structure for answering stabbing queries on a set of dynamically maintained intervals. The external interval tree can be used in an optimal solution to the dynamic interval management problem, which is a central problem for objectoriented and temporal databases and for constraint logic programming. Part of the structure uses a novel weightbalancing technique for efficient worstcase manipulation of balanced trees of independent interest. The external interval tree, as well at our new balancing technique, have recently been used to develop several efficient external data structures.
Dynamization of the Trapezoid Method for Planar Point Location
, 1991
"... We present a fully dynamic data structure for point location in a monotone subdivision, based on the trapezoid method. The operations supported are insertion and deletion of vertices and edges, and horizontal translation of vertices. Let n be the current number of vertices of the subdivision. Point ..."
Abstract

Cited by 14 (4 self)
 Add to MetaCart
We present a fully dynamic data structure for point location in a monotone subdivision, based on the trapezoid method. The operations supported are insertion and deletion of vertices and edges, and horizontal translation of vertices. Let n be the current number of vertices of the subdivision. Point location queries take O(log n) time, while updates take O(log2 n) time. The space requirement is O(n log n). This is the first fully dynamic point location data structure for monotone subdivisions that achieves optimal query time.
Data structures for halfplane proximity queries and incremental Voronoi diagrams
 In Proceedings of the 7th Latin American Symposium on Theoretical Informatics, volume 3887 of Lecture Notes in Computer Science
, 2006
"... We consider preprocessing a set S of n points in the plane that are in convex position into a data structure supporting queries of the following form: given a point q and a directed line ℓ in the plane, report the point of S that is farthest from (or, alternatively, nearest to) the point q subject t ..."
Abstract

Cited by 10 (3 self)
 Add to MetaCart
We consider preprocessing a set S of n points in the plane that are in convex position into a data structure supporting queries of the following form: given a point q and a directed line ℓ in the plane, report the point of S that is farthest from (or, alternatively, nearest to) the point q subject to being to the left of line ℓ. We present two data structures for this problem. The first data structure uses O(n 1+ε) space and preprocessing time, and answers queries in O(2 1/ε log n) time. The second data structure uses O(n log 3 n) space and polynomial preprocessing time, and answers queries in O(log n) time. These are the first solutions to the problem with O(log n) query time and o(n 2) space. In the process of developing the second data structure, we develop a new representation of nearestpoint and farthestpoint Voronoi diagrams of points in convex position. This representation supports insertion of new points in counterclockwise order using only O(log n) amortized pointer changes, subject to supporting O(log n)time pointlocation queries, even though every such update may make Θ(n) combinatorial changes to the Voronoi diagram. This data structure is the first demonstration that deterministically and incrementally constructed Voronoi diagrams can be maintained in o(n) pointer changes per operation while keeping O(log n)time pointlocation queries. 1
Connected Component and Simple Polygon Intersection Searching
 Proc. 3rd Workshop Algorithms Data Struct., Lecture Notes in Computer Science
, 1993
"... Efficient data structures are given for the following two query problems: preprocess a set P of simple polygons with a total of n edges, so that all polygons of P intersected by a query segment can be reported efficiently, and (ii) preprocess a set S of n segments, so that the connected components ..."
Abstract

Cited by 9 (2 self)
 Add to MetaCart
Efficient data structures are given for the following two query problems: preprocess a set P of simple polygons with a total of n edges, so that all polygons of P intersected by a query segment can be reported efficiently, and (ii) preprocess a set S of n segments, so that the connected components of the arrangement of S intersected by a query segment can be reported quickly. In these problems we do not want to return the polygons or connected components explicitly (i.e., we do not wish to report the segments defining the polygon or the segments lying in the connected components). Instead, we assume that the polygons (or connected components) are labeled and we just want to report their labels. We present data structures of size O(n 1+ffl ) that can answer a query in time O(n 1=2+ffl +k), where k is the output size. If the edges of P (or the segments in S) are orthogonal, the query time can be improved to O(log n + k) using O(n log n) space. We also present data structures that c...
Reliable Resource Searching in P2P Networks ⋆
"... Abstract. We study the problem of securely searching for resources in p2p networks where a constant fraction of the peers may act maliciously. We present two novel hashingbased schemes that can be employed to reliably support resource location and content retrieval queries, limiting the ability of ..."
Abstract
 Add to MetaCart
Abstract. We study the problem of securely searching for resources in p2p networks where a constant fraction of the peers may act maliciously. We present two novel hashingbased schemes that can be employed to reliably support resource location and content retrieval queries, limiting the ability of adversarial nodes to carry out attacks. Our schemes achieve scalability and load balancing and have small authentication overhead. In particular, for a network with n peers, resources are securely located with O(log 2 n) messages and content from a collection of m data items is securely retrieved with O(log nlog m) messages. Key words: peertopeer, overlay networks, distributed hash tables, oneway hash functions, digital signatures 1