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EFFICIENT ALGORITHMS FOR CLAUSELEARNING SAT SOLVERS
, 2004
"... Boolean satisfiability (SAT) is NPcomplete. No known algorithm for SAT is of polynomial time complexity. Yet, many of the SAT instances generated as a means of solving realworld electronic design automation problems are simple enough, structurally, that modern solvers can decide them efficiently. ..."
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Cited by 58 (0 self)
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Boolean satisfiability (SAT) is NPcomplete. No known algorithm for SAT is of polynomial time complexity. Yet, many of the SAT instances generated as a means of solving realworld electronic design automation problems are simple enough, structurally, that modern solvers can decide them efficiently. Consequently, SAT solvers are widely used in industry for logic verification. The most robust solver algorithms are poorly understood and only vaguely described in the literature of the field. We refine these algorithms, and present them clearly. We introduce several new techniques for Boolean constraint propagation that substantially improve solver efficiency. We explain why literal count decision strategies succeed, and on that basis, we introduce a new decision strategy that outperforms the state of the art. The culmination of this work is the most powerful SAT solver publically available.
Linear probing with constant independence
 In STOC ’07: Proceedings of the thirtyninth annual ACM symposium on Theory of computing
, 2007
"... Hashing with linear probing dates back to the 1950s, and is among the most studied algorithms. In recent years it has become one of the most important hash table organizations since it uses the cache of modern computers very well. Unfortunately, previous analyses rely either on complicated and space ..."
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Cited by 15 (2 self)
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Hashing with linear probing dates back to the 1950s, and is among the most studied algorithms. In recent years it has become one of the most important hash table organizations since it uses the cache of modern computers very well. Unfortunately, previous analyses rely either on complicated and space consuming hash functions, or on the unrealistic assumption of free access to a truly random hash function. Already Carter and Wegman, in their seminal paper on universal hashing, raised the question of extending their analysis to linear probing. However, we show in this paper that linear probing using a pairwise independent family may have expected logarithmic cost per operation. On the positive side, we show that 5wise independence is enough to ensure constant expected time per operation. This resolves the question of finding a space and time efficient hash function that provably ensures good performance for linear probing.
Sorting on a Parallel Pointer Machine with Applications to Set Expression Evaluation
 J. ACM
, 1989
"... We present optimal algorithms for sorting on parallel CREW and EREW versions of the pointer machine model. Intuitively, one can view our methods as being based on a parallel mergesort using linked lists rather than arrays (the usual parallel data structure). We also show how to exploit the "locality ..."
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Cited by 14 (5 self)
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We present optimal algorithms for sorting on parallel CREW and EREW versions of the pointer machine model. Intuitively, one can view our methods as being based on a parallel mergesort using linked lists rather than arrays (the usual parallel data structure). We also show how to exploit the "locality" of our approach to solve the set expression evaluation problem, a problem with applications to database querying and logicprogramming, in O(log n) time using O(n) processors. Interestingly, this is an asymptotic improvement over what seems possible using previous techniques. Categories and Subject Descriptors: E.1 [Data Structures]: arrays, lists; F.2.2. [Analysis of Algorithms and Problem Complexity]: Nonnumerical Algorithms and Problemssorting and searching General Terms: Algorithms, Theory, Verification Additional Key Words and Phrases: parallel algorithms, PRAM, pointer machine, linking automaton, expression evaluation, mergesort, cascade merging 1 Introduction One of the primar...
The Design and Verification of a Sorter Core
, 2001
"... The design and verification of a high speed sorter core is presented. We present several techniques and tools used to verify the functionality of the sorter. The sorter is a periodic sorter based on recursive butterfly networks. Having a design language that is wellsuited to describing these networ ..."
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Cited by 13 (5 self)
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The design and verification of a high speed sorter core is presented. We present several techniques and tools used to verify the functionality of the sorter. The sorter is a periodic sorter based on recursive butterfly networks. Having a design language that is wellsuited to describing these networks has helped us to explore the design space far more effectively than is possible using conventional hardware description languages.
Optimal TimeSpace TradeOffs for Sorting
 In Proc. 39th IEEE Sympos. Found. Comput. Sci
, 1998
"... We study the fundamental problem of sorting in a sequential model of computation and in particular consider the timespace tradeoff (product of time and space) for this problem. ..."
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Cited by 10 (0 self)
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We study the fundamental problem of sorting in a sequential model of computation and in particular consider the timespace tradeoff (product of time and space) for this problem.
HashBased Techniques for HighSpeed Packet Processing
"... Abstract Hashing is an extremely useful technique for a variety of highspeed packetprocessing applications in routers. In this chapter, we survey much of the recent work in this area, paying particular attention to the interaction between theoretical and applied research. We assume very little bac ..."
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Cited by 9 (1 self)
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Abstract Hashing is an extremely useful technique for a variety of highspeed packetprocessing applications in routers. In this chapter, we survey much of the recent work in this area, paying particular attention to the interaction between theoretical and applied research. We assume very little background in either the theory or applications of hashing, reviewing the fundamentals as necessary. 1
Genetic Algorithms for Scheduling
"... This paper provides a survey of the application of genetic algorithms (GAs) to scheduling. Although it focuses on manufacturing scheduling, particularly jobshop problems, it does outline work in other areas such as transport scheduling and network routing. GA research in closely related problems, s ..."
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Cited by 8 (0 self)
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This paper provides a survey of the application of genetic algorithms (GAs) to scheduling. Although it focuses on manufacturing scheduling, particularly jobshop problems, it does outline work in other areas such as transport scheduling and network routing. GA research in closely related problems, such as bin packing and the TSP, are also covered. Finally, it is shown how distributed parallel GAs may allow practically beneficial recharacterisations of highly complex general scheduling problems. 1 Introduction Practical scheduling problems are numerous and varied. However, many of them share two important characteristics  they are very difficult, and good quality solutions bring highly tangible benefits. In general, scheduling problems are NPhard [37], consequently there are no known algorithms guaranteed to give an optimal solution and run in polynomial time. This has lead to a long line of techniques emanating from the fields of AI and OR that provide approximate solutions to fai...
Smoothed analysis of binary search trees and quicksort under additive noise
 Report 07039, Electronic Colloquium on Computational Complexity (ECCC
, 2007
"... Abstract. Binary search trees are a fundamental data structure and their height plays a key role in the analysis of divideandconquer algorithms like quicksort. We analyze their smoothed height under additive uniform noise: An adversary chooses a sequence of n real numbers in the range [0, 1], each ..."
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Cited by 3 (2 self)
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Abstract. Binary search trees are a fundamental data structure and their height plays a key role in the analysis of divideandconquer algorithms like quicksort. We analyze their smoothed height under additive uniform noise: An adversary chooses a sequence of n real numbers in the range [0, 1], each number is individually perturbed by adding a value drawn uniformly at random from an interval of size d, and the resulting numbers are inserted into a search tree. An analysis of the smoothed tree height subject to n and d lies at the heart of our paper: We prove that the smoothed height of binary search trees is Θ ( p n/d+log n), where d ≥ 1/n may depend on n. Our analysis starts with the simpler problem of determining the smoothed number of lefttoright maxima in a sequence. We establish matching bounds, namely once more Θ ( p n/d + log n). We also apply our findings to the performance of the quicksort algorithm and prove that the smoothed number of comparisons made by quicksort is Θ ( n d+1 p n/d + n log n). 1
Coevolutionary Optimization of Fuzzy Logic Intelligence for Strategic Decision Support
"... Abstract—We present a description and initial results of a computer code that coevolves fuzzy logic rules to play a twosided zerosum competitive game. It is based on the TEMPO Military Planning Game that has been used to teach resource allocation to over 20 000 students over the past 40 years. No ..."
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Cited by 2 (0 self)
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Abstract—We present a description and initial results of a computer code that coevolves fuzzy logic rules to play a twosided zerosum competitive game. It is based on the TEMPO Military Planning Game that has been used to teach resource allocation to over 20 000 students over the past 40 years. No feasible algorithm for optimal play is known. The coevolved rules, when pitted against human players, usually win the first few competitions. For reasons not yet understood, the evolved rules (found in a symmetrical competition) place little value on information concerning the play of the opponent. Index Terms—Coevolution, fuzzy rules, games, resource allocation, strategic decisions. I.
A Random Walk in Statistical Physics
, 2001
"... This thesis deals with some aspects of the physics of disordered systems. It consists of four papers and an introductory part. An introduction ..."
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Cited by 1 (0 self)
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This thesis deals with some aspects of the physics of disordered systems. It consists of four papers and an introductory part. An introduction