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Foundations of Computer Science, 1997. Proceedings., 38th Annual Symposium on

Date 20-22 Oct. 1997

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  • Proceedings 38th Annual Symposium on Foundations of Computer Science

    Publication Year: 1997
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    Freely Available from IEEE
  • Author index

    Publication Year: 1997, Page(s):605 - 606
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    Freely Available from IEEE
  • A concrete security treatment of symmetric encryption

    Publication Year: 1997, Page(s):394 - 403
    Cited by:  Papers (58)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    We study notions and schemes for symmetric (ie. private key) encryption in a concrete security framework. We give four different notions of security against chosen plaintext attack and analyze the concrete complexity of reductions among them, providing both upper and lower bounds, and obtaining tight relations. In this way we classify notions (even though polynomially reducible to each other) as s... View full abstract»

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  • On the complexity of a set-union problem

    Publication Year: 1997, Page(s):110 - 115
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (552 KB)

    We consider a simple data structure supporting the following operations: (i) create a new singleton set; (ii) create a new set which is the union of two pre-existing sets; (iii) determine whether a given element is in a particular set. We prove both lower and upper bounds for an implementation of such a data structure. In a restricted model we show that no deterministic implementation can be bette... View full abstract»

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  • Alternating-time temporal logic

    Publication Year: 1997, Page(s):100 - 109
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (984 KB)

    Temporal logic comes in two varieties: linear-time temporal logic assumes implicit universal quantification over all paths that are generated by system moves; branching-time temporal logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of temporal logic: alternating-time temporal logic offers selective quantification over those p... View full abstract»

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  • Deterministic superimposed coding with applications to pattern matching

    Publication Year: 1997, Page(s):127 - 136
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    A superimposed code is a set of binary vectors having the property that no vector is contained in a boolean sum (i.e. bitwise OR) of a small number of others. Such codes are used in information retrieval for constructing so-called signature files; they also have applications in other areas. In this paper we introduce a new notion of data-dependent superimposed codes and give a deterministic algori... View full abstract»

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  • Minimizing flow time nonclairvoyantly

    Publication Year: 1997, Page(s):345 - 352
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (604 KB)

    We consider the problem of scheduling a collection of dynamically arriving jobs with unknown execution times so as to minimize the average response/flow time. This is the classic CPU scheduling problem faced by time sharing operating systems. In the standard 3-field scheduling notation this is the nonclairvoyant version of 1|pmtn, rj|ΣFj. Its easy to see that every algo... View full abstract»

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  • Tight bounds for depth-two superconcentrators

    Publication Year: 1997, Page(s):585 - 594
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    We show that the minimum size of a depth-two N-superconcentrator is Θ(Nlog2N/loglogN). Before this work, optimal bounds were known for all depths except two. For the upper bound, we build superconcentrators by putting together a small number of disperser graphs; these disperser graphs are obtained using a probabilistic argument. We present two different methods for showing lower b... View full abstract»

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  • Does parallel repetition lower the error in computationally sound protocols?

    Publication Year: 1997, Page(s):374 - 383
    Cited by:  Papers (4)  |  Patents (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (980 KB)

    Whether or not parallel repetition lowers the error has been a fundamental question in the theory of protocols, with applications in many different areas. It is well known that parallel repetition reduces the error at an exponential rate in interactive proofs and Arthur-Merlin games. It seems to have been taken for granted that the same is true in arguments, or other proofs where the soundness onl... View full abstract»

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  • Optimal suffix tree construction with large alphabets

    Publication Year: 1997, Page(s):137 - 143
    Cited by:  Papers (22)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    The suffix tree of a string is the fundamental data structure of combinatorial pattern matching. Weiner (1973), who introduced the data structure, gave an O(n)-time algorithm for building the suffix tree of an n-character string drawn from a constant size alphabet. In the comparison model, there is a trivial Ω(n log n)-time lower bound based on sorting, and Weiner's algorithm matches this bo... View full abstract»

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  • Replication is not needed: single database, computationally-private information retrieval

    Publication Year: 1997, Page(s):364 - 373
    Cited by:  Papers (82)  |  Patents (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (780 KB)

    We establish the following, quite unexpected, result: replication of data for the computational private information retrieval problem is not necessary. More specifically, based on the quadratic residuosity assumption, we present a single database, computationally private information retrieval scheme with O(nε) communication complexity for any ε>0 View full abstract»

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  • Improved bounds on planar k-sets and k-levels

    Publication Year: 1997, Page(s):156 - 161
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    We prove an O(nk1/3) upper bound for planar k-sets. This is the first considerable improvement on this bound after its early solutions approximately twenty seven years ago. Our proof technique also applies to improve the current bounds on the combinatorial complexities of k-levels in arrangements of line segments, k convex polygons in the union of n lines, parametric minimum spanning tr... View full abstract»

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  • Separation of the monotone NC hierarchy

    Publication Year: 1997, Page(s):234 - 243
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    We prove tight lower bounds, of up to nε, for the monotone depth of functions in monotone-P. As a result we achieve the separation of the following classes. 1. Monotone-NC≠monotone-P. 2. ∀i⩾1, monotone-NCi≠monotone-NCi+1. 3. More generally: For any integer function D(n), up to nε (for some ε>0), we give an explicit exa... View full abstract»

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  • On the power of quantum finite state automata

    Publication Year: 1997, Page(s):66 - 75
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (816 KB)

    In this paper, we introduce 1-way and 2-way quantum finite state automata (1qfa's and 2qfa's), which are the quantum analogues of deterministic, nondeterministic and probabilistic 1-way and 2-way finite state automata. We prove the following facts regarding 2qfa's. 1. For any ε>0, there is a 2qfa M which recognizes the non-regular language L={ambm|m⩾1} with (one-s... View full abstract»

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  • Nearly linear time approximation schemes for Euclidean TSP and other geometric problems

    Publication Year: 1997, Page(s):554 - 563
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (928 KB)

    We present a randomized polynomial time approximation scheme for Euclidean TSP in R2 that is substantially more efficient than our earlier scheme (1996) (and the scheme of Mitchell (1996)). For any fixed c>1 and any set of n nodes in the plane, the new scheme finds a (1+1/c)-approximation to the optimum traveling salesman tour in O(n(logn)O(c)) time. (Our earlier scheme ra... View full abstract»

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  • Global optimization using local information with applications to flow control

    Publication Year: 1997, Page(s):303 - 312
    Cited by:  Papers (16)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    Flow control in high speed networks requires distributed routers to make fast decisions based only on local information in allocating bandwidth to connections. While most previous work on this problem focuses on achieving local objective functions, in many cases it may be necessary to achieve global objectives such as maximizing the total flow. This problem illustrates one of the basic aspects of ... View full abstract»

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  • Weak random sources, hitting sets, and BPP simulations

    Publication Year: 1997, Page(s):264 - 272
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (696 KB)

    We show how to simulate any BPP algorithm in polynomial time using a weak random source of min-entropy rγ for any γ>0. This follows from a more general result about sampling with weak random sources. Our result matches an information-theoretic lower bound and solves a question that has been open for some years. The previous best results were a polynomial time simulation o... View full abstract»

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  • Randomized allocation processes

    Publication Year: 1997, Page(s):194 - 203
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (928 KB)

    We investigate various randomized processes allocating balls into bins that arise in applications in dynamic resource allocation and on-line load balancing. We consider the scenario when m balls arriving sequentially are to be allocated into n bins on-line and without using a global controller. Traditionally, the main aim of allocation processes is to place the balls into bins to minimize the maxi... View full abstract»

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  • Finding an even hole in a graph

    Publication Year: 1997, Page(s):480 - 485
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    A hole in a graph is a chordless cycle of length greater than three. In this paper we present a decomposition theorem for graphs that contain no even hole. This theorem yields a polytime algorithm to recognize whether a graph contains an even hole View full abstract»

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  • New directions in cryptography: twenty some years later (or cryptograpy and complexity theory: a match made in heaven)

    Publication Year: 1997, Page(s):314 - 324
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (836 KB)

    Diffie and Hellman (1976) published their fundamental paper on new directions in cryptography, in which they announced that “we stand on the brink of a revolution in cryptography”. Twenty some years later, we survey some of the progress made in cryptography during this time. We especially focus on the successful interplay between complexity theory and cryptography, witnessed perhaps mo... View full abstract»

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  • Nearly tight bounds on the learnability of evolution

    Publication Year: 1997, Page(s):524 - 533
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    Evolution is often modeled as a stochastic process which modifies DNA. One of the most popular and successful such processes are the Cavender-Farris (CF) trees, which are represented as edge weighted trees. The Phylogeny Construction Problem is that of, given κ samples drawn from a CF tree, output a CF tree which is close to the original. Each CF tree naturally defines a random variable, and... View full abstract»

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  • A faster deterministic algorithm for minimum spanning trees

    Publication Year: 1997, Page(s):22 - 31
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (860 KB)

    A deterministic algorithm for computing a minimum spanning tree of a connected graph is presented. Its running time is O(m α log α), where α=α(m,n) is a functional inverse of Ackermann's function and n (resp. m) is the number of vertices (resp. edges). This improves on the previous, ten-year old bound of (roughly) O(m log log* m) View full abstract»

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  • Making nondeterminism unambiguous

    Publication Year: 1997, Page(s):244 - 253
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    We show that in the context of nonuniform complexity, nondeterministic logarithmic space bounded computation can be made unambiguous. An analogous result holds for the class of problems reducible to context-free languages. In terms of complexity classes, this can be stated as: NL/poly=UL/poly LogCFL/poly=UAuxPDA(log n, nO(1))/poly View full abstract»

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  • A random sampling based algorithm for learning the intersection of half-spaces

    Publication Year: 1997, Page(s):508 - 513
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    We present an algorithm for learning the intersection of half spaces in n dimensions. Over nearly uniform distributions, it runs in polynomial time for up to O(logn/loglogn) half spaces or, more generally for any number of half spaces whose normal vectors lie in an O(log n/log log n) dimensional subspace. Over less restricted “non-concentrated” distributions it runs in polynomial time ... View full abstract»

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  • Randomized and deterministic algorithms for the dimension of algebraic varieties

    Publication Year: 1997, Page(s):36 - 45
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (848 KB)

    We prove old and new results on the complexity of computing the dimension of algebraic varieties. In particular, we show that this problem is NP-complete in the Blum-Shub-Smale model of computation over C, that it admits a sO(1)DO(n) deterministic algorithm, and that for systems with integer coefficients it is in the Arthur-Merlin class under the Generalized Riemann Hypothesi... View full abstract»

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