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[1991] Proceedings 32nd Annual Symposium of Foundations of Computer Science

1-4 Oct. 1991

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Displaying Results 1 - 25 of 86
  • Proceedings 32nd Annual Symposium on Foundations of Computer Science (Cat. No.91CH3062-7)

    Publication Year: 1991
    Request permission for commercial reuse | PDF file iconPDF (17 KB)
    Freely Available from IEEE
  • Reporting points in halfspaces

    Publication Year: 1991, Page(s):207 - 215
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    The author considers the halfspace range reporting problem: Given a finite set P of points in Ed, preprocess it so that given a query halfspace γ, the points of p∩γ can be reported efficiently. It is shown that, with almost linear storage, this problem can be solved substantially more efficiently than the more general simplex range searching pr... View full abstract»

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  • Dynamic maintenance of geometric structures made easy

    Publication Year: 1991, Page(s):197 - 206
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (896 KB)

    The problem of dynamically maintaining geometric structures is considered. A technique is proposed that uses randomized incremental algorithms which are augmented to allow deletions of objects. A model for distributions on the possible input sequences of insertions and deletions is developed and analyzed using R. Seidel's backwards analysis. It is further shown how to apply this to maintain Vorono... View full abstract»

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  • Randomized multidimensional search trees: lazy balancing and dynamic shuffling

    Publication Year: 1991, Page(s):180 - 196
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1628 KB)

    A randomized technique, called dynamic shuffling, is given for multidimensional dynamic search. This technique, when specialized to the problem of searching in sorted lists, yields the previously known randomized binary trees (treaps). The crux of the technique is a multidimensional generalization of the rotation operation on binary search trees. Simultaneously, it is shown how to dynamize the ran... View full abstract»

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  • Exact learning of read-twice DNF formulas

    Publication Year: 1991, Page(s):170 - 179
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (840 KB)

    A polynomial-time algorithm is presented for exactly learning the class of read-twice DNF formulas, i.e. Boolean formulas in disjunctive normal form where each variable appears at most twice. The (standard) protocol used allows the learning algorithm to query whether a given assignment of Boolean variables satisfies the DNF formula to be learned (membership queries), as well as to obtain counterex... View full abstract»

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  • Fully parallelized multi prover protocols for NEXP-time

    Publication Year: 1991, Page(s):13 - 18
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    A major open problem in the theory of multiprover protocols is to characterize the languages which can be accepted by fully parallelized protocols which achieve an exponentially low probability of cheating in a single round. The problem was motivated by the observation that the probability of cheating the n parallel executions of a multiprover protocol can be exponentially higher than the... View full abstract»

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  • On selecting a satisfying truth assignment

    Publication Year: 1991, Page(s):163 - 169
    Cited by:  Papers (27)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (524 KB)

    The complexity of certain natural generalizations of satisfiability, in which one of the possibly exponentially many satisfying truth assignments must be selected, is studied. Two natural selection criteria, default preference and minimality (circumscription), are considered. The thrust of the complexity results seems to be that hard problems become harder, while easy problems remain easy. This co... View full abstract»

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  • Approximating clique is almost NP-complete

    Publication Year: 1991, Page(s):2 - 12
    Cited by:  Papers (75)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    The computational complexity of approximating ω(G), the size of the largest clique in a graph G, within a given factor is considered. It is shown that if certain approximation procedures exist, then EXPTIME=NEXPTIME and NP=P View full abstract»

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  • How to learn an unknown environment

    Publication Year: 1991, Page(s):298 - 303
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    The authors consider the problem faced by a newborn that must explore and learn an unknown room with obstacles in it. They seek algorithms that achieve a bounded ratio of the worst-case distance traversed in order to see all visible points of the environment (thus creating a map), divided by the optimum distance needed to verify the map. The situation is complicated by the fact that the latter off... View full abstract»

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  • Communication complexity for parallel divide-and-conquer

    Publication Year: 1991, Page(s):151 - 162
    Cited by:  Papers (11)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (888 KB)

    The relationship between parallel computation cost and communication cost for performing divide-and-conquer (D&C) computations on a parallel system of p processors is studied. The parallel computation cost is the maximal number of the D&C nodes that any processor in the parallel system may expand, whereas the communication cost is the total number of cross nodes (nodes generated b... View full abstract»

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  • Competitive algorithms for layered graph traversal

    Publication Year: 1991, Page(s):288 - 297
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    A layered graph is a connected, weighted graph whose vertices are partitioned into sets L0={s}, L 1, L2, . . ., and whose edges run between consecutive layers. Its width is max{|Li|}. In the online layered graph traversal problem, a searcher starts at s in a layered graph of unknown width and tries to... View full abstract»

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  • Concentrated regular data streams on grids: sorting and routing near to the bisection bound

    Publication Year: 1991, Page(s):141 - 150
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (800 KB)

    Sorting and routing on r-dimensional n×. . .×n grids of processors is studied. Deterministic algorithms are presented for h-h problems, h⩾1, where each processor initially and finally contains h elements. It is shown that the classical 1-1 sorting can be solved with (2r-1.5)n+o(n) tra... View full abstract»

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  • An asynchronous two-dimensional self-correcting cellular automaton

    Publication Year: 1991, Page(s):278 - 285
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    Earlier work of P. Gacs and J. Reif (see J. Comput. Syst. Sci., vol.36, no.2, p.125-147 (1988)) on reliable computation using cellular automata is extended to asynchronous cellular automata. The goal is to find ways to implement computations of arbitrary size by a homogeneous asynchronous array of unreliable elementary components. An asynchronous two-dimensional cellular automaton is constructed s... View full abstract»

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  • Scheduling parallel machines on-line

    Publication Year: 1991, Page(s):131 - 140
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (832 KB)

    The authors study the problem of scheduling jobs on parallel machines when the existence of a job is not known until an unknown release date and the processing requirement of a job is not known until the job is processed to completion. They demonstrate two general algorithmic techniques for converting existing polynomial-time algorithms that require complete knowledge about the input data into alg... View full abstract»

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  • Self-stabilization by local checking and correction

    Publication Year: 1991, Page(s):268 - 277
    Cited by:  Papers (55)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (816 KB)

    The first self-stabilizing end-to-end communication protocol and the most efficient known self-stabilizing network reset protocol are introduced. A simple method of local checking and correction, by which distributed protocols can be made self-stabilizing without the use of unbounded counters, is used. The self-stabilization model distinguishes between catastrophic faults that abstract arbitrary c... View full abstract»

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  • On-line scheduling in the presence of overload

    Publication Year: 1991, Page(s):100 - 110
    Cited by:  Papers (43)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    The preemptive scheduling of sporadic tasks on a uniprocessor is considered. A task may arrive at any time, and is characterized by a value that reflects its importance, an execution time that is the amount of processor time needed to completely execute the task, and a deadline by which the task is to complete execution. The goal is to maximize the sum of the values of the completed tasks. An onli... View full abstract»

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  • Shrinkage of de Morgan formulae under restriction

    Publication Year: 1991, Page(s):324 - 333
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    It is shown that a random restriction leaving only a fraction ∈ of the input variables unassigned reduces the expected de Morgan formula size of the induced function by a factor of O(∈ 1.63). This is an improvement over previous results. The new exponent yields an increased lower bound of approximately n2.63 for the de Morgan formula size of a func... View full abstract»

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  • Optimal prefetching via data compression

    Publication Year: 1991, Page(s):121 - 130
    Cited by:  Papers (25)  |  Patents (48)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    A form of the competitive philosophy is applied to the problem of prefetching to develop an optimal universal prefetcher in terms of fault ratio, with particular applications to large-scale databases and hypertext systems. The algorithms are novel in that they are based on data compression techniques that are both theoretically optimal and good in practice. Intuitively, in order to compress data e... View full abstract»

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  • A theory of using history for equational systems with applications

    Publication Year: 1991, Page(s):348 - 357
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    A general theory of using a congruence closure based simplifier (CCNS) proposed by P. Chew (1980) for computing normal forms is developed, and several applications are presented. An independent set of postulates is given, and it is proved that CCNS can be used for any system that satisfies them. It is then shown that CCNS can be used for consistent convergent systems and for various kinds of prior... View full abstract»

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  • Lower bounds for polynomial evaluation and interpolation problems

    Publication Year: 1991, Page(s):378 - 383
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    It is shown that there is a set of points p1, p2,. . .,pn such that any algebraic program of depth d for polynomial evaluation (or interpolation) at these points has size Ω(n log n/log d). Moreover, if d is a constant, then a lower bound of Ω(n1+1/d) is obtained View full abstract»

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  • A linear time algorithm for triconnectivity augmentation

    Publication Year: 1991, Page(s):548 - 559
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1000 KB)

    The problem of finding the smallest set of edges whose addition triconnects an undirected graph is considered. This is a fundamental graph-theoretic problem that has applications in designing reliable networks and fault-tolerant computing. A linear time sequential algorithm is given for the problem. This is a substantial improvement over the best previous algorithm for this problem, which runs in ... View full abstract»

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  • Dynamic three-dimensional linear programming

    Publication Year: 1991, Page(s):488 - 494
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (592 KB)

    Linear programming optimizations on the intersection of k polyhedra in R3, represented by their outer recursive decompositions, are performed in expected time O(k log k log n+√k log k log3 n). This result is used to derive efficient algorithms for dynamic linear programming problems ill which const... View full abstract»

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  • Lower bounds for the complexity of reliable Boolean circuits with noisy gates

    Publication Year: 1991, Page(s):594 - 601
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    It is proved that the reliable computation of any Boolean function with, sensitivity s requires Ω(s log s) gates if the gates of the circuit fail independently with a fixed positive probability. The Ω(s log s) bound holds even if s is the block sensitivity instead of the sensitivity of the Boolean function. Some open problems are me... View full abstract»

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  • Distributed program checking: a paradigm for building self-stabilizing distributed protocols

    Publication Year: 1991, Page(s):258 - 267
    Cited by:  Papers (33)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (828 KB)

    The notion of distributed program checking as a means of making a distributed algorithm self-stabilizing is explored. A compiler that converts a deterministic synchronous protocol π for static networks into a self-stabilizing version of π for dynamic networks is described. If Tπ is the time complexity of π and D is a bound on the diameter of the final netwo... View full abstract»

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  • On the complexity of computing the homology type of a triangulation

    Publication Year: 1991, Page(s):650 - 661
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1076 KB)

    An algorithm for computing the homology type of a triangulation is analyzed. By triangulation is meant a finite simplicial complex; its homology type is given by its homology groups (with integer coefficients). The algorithm could be used in computer-aided design to tell whether two finite-element meshes or Bezier-spline surfaces are of the same topological type, and whether they can be embedded i... View full abstract»

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