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45
Compact routing schemes
 in SPAA ’01: Proceedings of the thirteenth annual ACM symposium on Parallel algorithms and architectures
"... We describe several compact routing schemes for general weighted undirected networks. Our schemes are simple and easy to implement. The routing tables stored at the nodes of the network are all very small. The headers attached to the routed messages, including the name of the destination, are extrem ..."
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Cited by 196 (7 self)
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We describe several compact routing schemes for general weighted undirected networks. Our schemes are simple and easy to implement. The routing tables stored at the nodes of the network are all very small. The headers attached to the routed messages, including the name of the destination, are extremely short. The routing decision at each node takes constant time. Yet, the stretch of these routing schemes, i.e., the worst ratio between the cost of the path on which a packet is routed and the cost of the cheapest path from source to destination, is a small constant. Our schemes achieve a nearoptimal tradeoff between the size of the routing tables used and the resulting stretch. More specifically, we obtain: 1. A routing scheme that uses only ~ O(n 1=2) bits of memory at each node of an nnode network that has stretch 3. The space is optimal, up to logarithmic factors, in the sense that
Representing trees of higher degree
 Algorithmica
, 1999
"... This paper focuses on space efficient representations of rooted trees that permit basic navigation in constant time. While most of the previous work has focused on binary trees, we turn our attention to trees of higher degree. We consider both cardinal trees (or kary tries), where each node has k ..."
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Cited by 74 (14 self)
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This paper focuses on space efficient representations of rooted trees that permit basic navigation in constant time. While most of the previous work has focused on binary trees, we turn our attention to trees of higher degree. We consider both cardinal trees (or kary tries), where each node has k slots, labelled {1,..., k}, each of which may have a reference to a child, and ordinal trees, where the children of each node are simply ordered. Our representations use a number of bits close to the information theoretic lower bound and support operations in constant time. For ordinal trees we support the operations of finding the degree, parent, ith child and subtree size. For cardinal trees the structure also supports finding the child labeled i of a given node apart from the ordinal tree operations. These representations also provide a mapping from the n nodes of the tree onto the integers {1,..., n}, giving unique labels to the nodes of the tree. This labelling can be used to store satellite information with the nodes efficiently. 1
Internet Packet Filter Management and Rectangle Geometry
, 2001
"... We consider rule sets for internet packet routing and filtering, where each rule consists of a range of source addresses, a range of destination addresses, a priority, and an action. A given packet should be handled by the action from the maximum priority rule that matches its source and destination ..."
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Cited by 69 (1 self)
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We consider rule sets for internet packet routing and filtering, where each rule consists of a range of source addresses, a range of destination addresses, a priority, and an action. A given packet should be handled by the action from the maximum priority rule that matches its source and destination. We describe new data structures for quickly finding the rule matching an incoming packet, in nearlinear space, and a new algorithm for determining whether a rule set contains any conflicts, in time O(n 3/2 ). 1 Introduction The working of the current Internet and its posited evolution depend on efficient packet filtering mechanisms: databases of rules, maintained at various parts of the network, which use patterns to filter out sets of IP packets and specify actions to be performed on those sets. Typical filter patterns are based on packet header information such as the source or destination IP addresses. The actions to be performed depend on where the packet filtering is performed i...
New data structures for orthogonal range searching
 In Proc. 41st IEEE Symposium on Foundations of Computer Science
, 2000
"... ..."
Compressed suffix trees with full functionality
 Theory of Computing Systems
"... We introduce new data structures for compressed suffix trees whose size are linear in the text size. The size is measured in bits; thus they occupy only O(n log A) bits for a text of length n on an alphabet A. This is a remarkable improvement on current suffix trees which require O(n log n) bits. ..."
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Cited by 52 (5 self)
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We introduce new data structures for compressed suffix trees whose size are linear in the text size. The size is measured in bits; thus they occupy only O(n log A) bits for a text of length n on an alphabet A. This is a remarkable improvement on current suffix trees which require O(n log n) bits. Though some components of suffix trees have been compressed, there is no linearsize data structure for suffix trees with full functionality such as computing suffix links, stringdepths and lowest common ancestors. The data structure proposed in this paper is the first one that has linear size and supports all operations efficiently. Any algorithm running on a suffix tree can also be executed on our compressed suffix trees with a slight slowdown of a factor of polylog(n). 1
Breaking a TimeandSpace Barrier in Constructing FullText Indices
"... Suffix trees and suffix arrays are the most prominent fulltext indices, and their construction algorithms are well studied. It has been open for a long time whether these indicescan be constructed in both o(n log n) time and o(n log n)bit working space, where n denotes the length of the text. Int ..."
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Cited by 50 (3 self)
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Suffix trees and suffix arrays are the most prominent fulltext indices, and their construction algorithms are well studied. It has been open for a long time whether these indicescan be constructed in both o(n log n) time and o(n log n)bit working space, where n denotes the length of the text. Inthe literature, the fastest algorithm runs in O(n) time, whileit requires O(n log n)bit working space. On the other hand,the most spaceefficient algorithm requires O(n)bit working space while it runs in O(n log n) time. This paper breaks the longstanding timeandspace barrier under the unitcost word RAM. We give an algorithm for constructing the suffix array which takes O(n) time and O(n)bit working space, for texts with constantsize alphabets. Note that both the time and the space bounds are optimal. For constructing the suffix tree, our algorithm requires O(n logffl n) time and O(n)bit working space forany 0! ffl! 1. Apart from that, our algorithm can alsobe adopted to build other existing fulltext indices, such as
Tight(er) Worstcase Bounds on Dynamic Searching and Priority Queues
 In STOC’2000
, 2000
"... We introduce a novel technique for converting static polynomial space search structures for ordered sets into fullydynamic linear space data structures. Based on this we present optimal bounds for dynamic integer searching, including finger search, and exponentially improved bounds for priority queu ..."
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Cited by 43 (2 self)
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We introduce a novel technique for converting static polynomial space search structures for ordered sets into fullydynamic linear space data structures. Based on this we present optimal bounds for dynamic integer searching, including finger search, and exponentially improved bounds for priority queues.
Accountable Certificate Management Using Undeniable Attestations
 COMPUTER AND COMMUNICATIONS SECURITY
, 2000
"... This paper initiates a study of accountable certificate management methods, necessary to support longterm authenticity of digital documents. Our main contribution is a model for accountable certificate management, where clients receive attestations confirming inclusion/removal of their certificates ..."
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Cited by 39 (3 self)
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This paper initiates a study of accountable certificate management methods, necessary to support longterm authenticity of digital documents. Our main contribution is a model for accountable certificate management, where clients receive attestations confirming inclusion/removal of their certificates from the database of valid certificates. We explain why accountability depends on the inability of the third parties to create contradictory attestations. After that we define an undeniable attester as a primitive that provides efficient attestation creation, publishing and verification, so that it is intractable to create contradictory attestations. We introduce authenticated search trees and build an efficient undeniable attester upon them. The proposed system is the first accountable longterm certificate management system. Moreover, authenticated search trees can be used in many securitycritical applications instead of the (sorted) hash trees to reduce trust in the authorities, without decrease in efficiency. Therefore, the undeniable attester promises looks like a very useful cryptographic primitive with a wide range of applications.
Deterministic Dictionaries
, 2001
"... It is shown that a static dictionary that offers constanttime access to n elements with wbit keys and occupies O(n) words of memory can be constructed deterministically in O(n log n) time on a unitcost RAM with word length w and a standard instruction set including multiplication. Whereas a rando ..."
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Cited by 34 (4 self)
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It is shown that a static dictionary that offers constanttime access to n elements with wbit keys and occupies O(n) words of memory can be constructed deterministically in O(n log n) time on a unitcost RAM with word length w and a standard instruction set including multiplication. Whereas a randomized construction working in linear expected time was known, the running time of the best previous deterministic algorithm was Ω(n²). Using a standard dynamization technique, the first deterministic dynamic dictionary with constant lookup time and sublinear update time is derived. The new algorithms are weakly nonuniform; i.e., they require access to a fixed number of precomputed constants dependent on w. The main technical tools employed are unitcost errorcorrecting codes, word parallelism, and derandomization using conditional expectations.
Cell probe complexity  a survey
 In 19th Conference on the Foundations of Software Technology and Theoretical Computer Science (FSTTCS), 1999. Advances in Data Structures Workshop
"... The cell probe model is a general, combinatorial model of data structures. We give a survey of known results about the cell probe complexity of static and dynamic data structure problems, with an emphasis on techniques for proving lower bounds. 1 ..."
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Cited by 29 (0 self)
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The cell probe model is a general, combinatorial model of data structures. We give a survey of known results about the cell probe complexity of static and dynamic data structure problems, with an emphasis on techniques for proving lower bounds. 1