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97
A graphtheory algorithm for rapid protein sidechain prediction
 PROTEIN SCI
, 2003
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Ranking and unranking permutations in linear time
 INFORMATION PROCESSING LETTERS 79 (2001) 281–284
, 2001
"... A ranking function for the permutations on n symbols assigns a unique integer in the range [0,n!−1] to each of the n! permutations. The corresponding unranking function is the inverse: given an integer between 0 and n!−1, the value of the function is the permutation having this rank. We present simp ..."
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Cited by 37 (0 self)
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A ranking function for the permutations on n symbols assigns a unique integer in the range [0,n!−1] to each of the n! permutations. The corresponding unranking function is the inverse: given an integer between 0 and n!−1, the value of the function is the permutation having this rank. We present simple ranking and unranking algorithms for permutations that can be computed using O(n) arithmetic operations.
Nearoptimal anytime coalition structure generation
 In Proceedings of the Twentieth International Joint Conference on Artificial Intelligence (IJCAI07
, 2007
"... Forming effective coalitions is a major research challenge in the field of multiagent systems. Central to this endeavour is the problem of determining the best set of agents that should participate in a given team. To this end, in this paper, we present a novel, anytime algorithm for coalition stru ..."
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Cited by 34 (10 self)
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Forming effective coalitions is a major research challenge in the field of multiagent systems. Central to this endeavour is the problem of determining the best set of agents that should participate in a given team. To this end, in this paper, we present a novel, anytime algorithm for coalition structure generation that is faster than previous anytime algorithms designed for this purpose. Our algorithm can generate solutions that either have a tight bound from the optimal or are optimal (depending on the objective) and works by partitioning the space in terms of a small set of elements that represent structures which contain coalitions of particular sizes. It then performs an online heuristic search that prunes the space and only considers valid and nonredundant coalition structures. We empirically show that we are able to find solutions that are, in the worst case, 99 % efficient in 0.0043% of the time to find the optimal value by the state of the art dynamic programming (DP) algorithm (for 20 agents), using 33 % less memory. 1
Some babystep giantstep algorithms for the low hamming weight discrete logarithm problem
 MATHEMATICS OF COMPUTATION
, 2001
"... In this paper, we present several babystep giantstep algorithms for the low hamming weight discrete logarithm problem. In this version of the discrete log problem, we are required to find a discrete logarithm in a finite group of order approximately 2m, given that the unknown logarithm has a spe ..."
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Cited by 30 (3 self)
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In this paper, we present several babystep giantstep algorithms for the low hamming weight discrete logarithm problem. In this version of the discrete log problem, we are required to find a discrete logarithm in a finite group of order approximately 2m, given that the unknown logarithm has a specified number of 1’s, say t, in its binary representation. Heiman and Odlyzko presented the first algorithms for this problem. Unpublished improvements � � � � by Coppersmith include a deterministic algorithm with � complexity m/2 √t � �� m/2 O m, and a Las Vegas algorithm with complexity O t/2 t/2 We perform an averagecase analysis of Coppersmith’s deterministic algorithm. The averagecase complexity achieves only a constant factor speedup
Defending DSSSbased Broadcast Communication against Insider Jammers via Delayed SeedDisclosure
 ACSAC '10
, 2010
"... Spread spectrum techniques such as Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping (FH) have been commonly used for antijamming wireless communication. However, traditional spread spectrum techniques require that sender and receivers share a common secret in order to agree upon, for ex ..."
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Cited by 14 (4 self)
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Spread spectrum techniques such as Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping (FH) have been commonly used for antijamming wireless communication. However, traditional spread spectrum techniques require that sender and receivers share a common secret in order to agree upon, for example, a common hopping sequence (in FH) or a common spreading code sequence (in DSSS). Such a requirement prevents these techniques from being effective for antijamming broadcast communication, where a jammer may learn the key from a compromised receiver and then disrupt the wireless communication. In this paper, we develop a novel Delayed SeedDisclosure DSSS (DSDDSSS) scheme for efficient antijamming broadcast communication. DSDDSSS achieves its antijamming capability through randomly generating the spreading code sequence for each message using a random seed and delaying the disclosure of the seed at the end of the message. We also develop an effective protection mechanism for seed disclosure using contentbased code subset selection. DSDDSSS is superior to all previous attempts for antijamming spread spectrum broadcast communication without shared keys. In particular, even if a jammer possesses realtime online analysis capability to launch reactive jamming attacks, DSDDSSS can still defeat the jamming attacks with a very high probability. We evaluate DSDDSSS through both theoretical analysis and a prototype implementation based on GNU Radio; our evaluation results demonstrate that DSDDSSS is practical and have superior security properties.
Design and Implementation of Reconfigurable Processor for Problems of Combinatorial Computations
 Combinatorial Computation, Journal of Systems Architecture, Special Issue on Reconfigurable Systems
, 2003
"... The paper analyses different techniques that might be employed in order to solve various problems of combinatorial optimization and argues that the best results can be achieved by the use of software running on a generalpurpose computer together with an FPGAbased reconfigurable coprocessor. It su ..."
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Cited by 14 (9 self)
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The paper analyses different techniques that might be employed in order to solve various problems of combinatorial optimization and argues that the best results can be achieved by the use of software running on a generalpurpose computer together with an FPGAbased reconfigurable coprocessor. It suggests an architecture for a combinatorial coprocessor that is based on hardware templates and consists of reconfigurable functional and control units. Finally the paper demonstrates how the coprocessor can be applied to two practical applications formulated over discrete matrices, the Boolean satisfiability and covering problems.
Using Element Clustering to Increase the Efficiency of XML Schema Matching
 OntologyDriven Semantic Matches between Database Schemas,” Proceedings of the twentysecond International Conference on Data Engineering
, 2006
"... Schema matching attempts to discover semantic mappings between elements of two schemas. Elements are cross compared using various heuristics (e.g., name, datatype, and structure similarity). Seen from a broader perspective, the schema matching problem is a combinatorial problem with an exponential ..."
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Cited by 13 (0 self)
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Schema matching attempts to discover semantic mappings between elements of two schemas. Elements are cross compared using various heuristics (e.g., name, datatype, and structure similarity). Seen from a broader perspective, the schema matching problem is a combinatorial problem with an exponential complexity. This makes the naive matching algorithms for large schemas prohibitively inefficient. In this paper we propose a clustering based technique for improving the efficiency of large scale schema matching. The technique inserts clustering as an intermediate step into existing schema matching algorithms. Clustering partitions schemas and reduces the overall matching load, and creates a possibility to trade between the efficiency and effectiveness. The technique can be used in addition to other optimization techniques. In the paper we describe the technique, validate the performance of one implementation of the technique, and open directions for future research. 1.
Preference queries over sets
 In ICDE
, 2011
"... Abstract—We propose a “logic + SQL ” framework for set preferences. Candidate best sets are represented using profiles consisting of scalar features. This reduces set preferences to tuple preferences over set profiles. We propose two optimization techniques: superpreference and Mrelation. Superpref ..."
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Cited by 12 (1 self)
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Abstract—We propose a “logic + SQL ” framework for set preferences. Candidate best sets are represented using profiles consisting of scalar features. This reduces set preferences to tuple preferences over set profiles. We propose two optimization techniques: superpreference and Mrelation. Superpreference targets dominated profiles. It reduces the input size by filtering out tuples not belonging to any best ksubset. Mrelation targets repeated profiles. It consolidates tuples that are exchangeable with regard to the given set preference, and therefore avoids redundant computation of the same profile. We show the results of an experimental study that demonstrates the efficacy of the optimizations. I.
2006): "Allowing Overlapping Boundaries in Source Code using a Search Based Approach to Concept Binding
 Proceedings of the 22nd IEEE International Conference on Software Maintenance. ISBN 0769523544, IEEE Computer Society
"... One approach to supporting program comprehension involves binding concepts to source code. Previously proposed approaches to concept binding have enforced nonoverlapping boundaries. However, realworld programs may contain overlapping concepts. This paper presents techniques to allow boundary overla ..."
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Cited by 12 (3 self)
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One approach to supporting program comprehension involves binding concepts to source code. Previously proposed approaches to concept binding have enforced nonoverlapping boundaries. However, realworld programs may contain overlapping concepts. This paper presents techniques to allow boundary overlap in the binding of concepts to source code. In order to allow boundaries to overlap, the concept binding problem is reformulated as a search problem. It is shown that the search space of overlapping concept bindings is exponentially large, indicating the suitability of samplingbased search algorithms. Hill climbing and genetic algorithms are introduced for sampling the space. The paper reports on experiments that apply these algorithms to 21 COBOL II programs taken from the commercial financial services sector. The results show that the genetic algorithm produces significantly better solutions than both the hill climber and random search. 1.
Program transformations for information personalization
, 2004
"... Personalization constitutes the mechanisms necessary to automatically customize information content, structure, and presentation to the enduser to reduce information overload. Unlike traditional approaches to personalization, the central theme of our approach is to model a website as a program and ..."
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Cited by 11 (10 self)
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Personalization constitutes the mechanisms necessary to automatically customize information content, structure, and presentation to the enduser to reduce information overload. Unlike traditional approaches to personalization, the central theme of our approach is to model a website as a program and conduct website transformation for personalization by program transformation (e.g., partial evaluation, program slicing). The goal of this paper is study personalization through a program transformation lens, and develop a formal model, based on program transformations, for personalized interaction with hierarchical hypermedia. The specific research issues addressed involve identifying and developing program representations and transformations suitable for classes of hierarchical hypermedia, and providing supplemental interactions for improving the personalized experience. The primary form of personalization discussed is outofturn interaction – a technique which empowers a user navigating a hierarchical website to postpone clicking on any of the hyperlinks presented on the current page and, instead, communicate the