737 research outputs found

    Black-Box Complexity: Breaking the O(nlogn)O(n \log n) Barrier of LeadingOnes

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    We show that the unrestricted black-box complexity of the nn-dimensional XOR- and permutation-invariant LeadingOnes function class is O(nlog(n)/loglogn)O(n \log (n) / \log \log n). This shows that the recent natural looking O(nlogn)O(n\log n) bound is not tight. The black-box optimization algorithm leading to this bound can be implemented in a way that only 3-ary unbiased variation operators are used. Hence our bound is also valid for the unbiased black-box complexity recently introduced by Lehre and Witt (GECCO 2010). The bound also remains valid if we impose the additional restriction that the black-box algorithm does not have access to the objective values but only to their relative order (ranking-based black-box complexity).Comment: 12 pages, to appear in the Proc. of Artificial Evolution 2011, LNCS 7401, Springer, 2012. For the unrestricted black-box complexity of LeadingOnes there is now a tight Θ(nloglogn)\Theta(n \log\log n) bound, cf. http://eccc.hpi-web.de/report/2012/087

    Weighted Automata and Logics for Infinite Nested Words

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    Nested words introduced by Alur and Madhusudan are used to capture structures with both linear and hierarchical order, e.g. XML documents, without losing valuable closure properties. Furthermore, Alur and Madhusudan introduced automata and equivalent logics for both finite and infinite nested words, thus extending B\"uchi's theorem to nested words. Recently, average and discounted computations of weights in quantitative systems found much interest. Here, we will introduce and investigate weighted automata models and weighted MSO logics for infinite nested words. As weight structures we consider valuation monoids which incorporate average and discounted computations of weights as well as the classical semirings. We show that under suitable assumptions, two resp. three fragments of our weighted logics can be transformed into each other. Moreover, we show that the logic fragments have the same expressive power as weighted nested word automata.Comment: LATA 2014, 12 page

    Development of the Mississippian-Pennsylvanian Unconformity in Indiana

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    In very early Pennsylvanian time the place nowcalled Indiana was the locus of subaerial erosion. About 8,000 square miles of this landscape is preserved in western Indiana beneath the rocks of the Pennsylvanian System. Data from 20,000 wells provide the evidence to reconstruct this surface and to describe its geomorphology. Six ancient physiographic regions that show clear relationships of landform to outcropping Mississippian bedrock have been identified. From north to south a distinctive topography is associated with each of the ancient outcrop areas of (1) the Borden Group, (2) the Sanders and Blue River Groups, (3) the West Baden Group, (4) the Stephensport Group, (5) the Tar Springs Formation through the Menard Limestone, and ( 6) the Palestine Sandstone through the Grove Church Shale. In northern Indiana the Mississippian-Pennsylvanian unconformity may represent as much as 8 million years of erosion. In southern Indiana that same unconformity may represent less than 3 million years of erosion

    Fourth order indirect integration method for black hole perturbations: even modes

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    On the basis of a recently proposed strategy of finite element integration in time domain for partial differential equations with a singular source term, we present a fourth order algorithm for non-rotating black hole perturbations in the Regge-Wheeler gauge. Herein, we address even perturbations induced by a particle plunging in. The forward time value at the upper node of the (r,t)(r^*,t) grid cell is obtained by an algebraic sum of i) the preceding node values of the same cell, ii) analytic expressions, related to the jump conditions on the wave function and its derivatives, iii) the values of the wave function at adjacent cells. In this approach, the numerical integration does not deal with the source and potential terms directly, for cells crossed by the particle world line. This scheme has also been applied to circular and eccentric orbits and it will be object of a forthcoming publication.Comment: This series of papers deals with EMRI for LISA. With the respect to the v1 version, the algorithm has been improved; convergence tests and references have been added; v2 is composed by 23 pages, and 6 figures. Paper accepted by Class. Quantum Gravity for the special issue on Theory Meets Data Analysis at Comparable and Extreme Mass Ratios (Capra and NRDA) at Perimeier Institute in June 201

    The theory of the exponential differential equations of semiabelian varieties

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    The complete first order theories of the exponential differential equations of semiabelian varieties are given. It is shown that these theories also arises from an amalgamation-with-predimension construction in the style of Hrushovski. The theory includes necessary and sufficient conditions for a system of equations to have a solution. The necessary condition generalizes Ax's differential fields version of Schanuel's conjecture to semiabelian varieties. There is a purely algebraic corollary, the "Weak CIT" for semiabelian varieties, which concerns the intersections of algebraic subgroups with algebraic varieties.Comment: 53 pages; v3: Substantial changes, including a completely new introductio

    Evolutionary design of a full-envelope full-authority flight control system for an unstable high-performance aircraft

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    The use of an evolutionary algorithm in the framework of H1 control theory is being considered as a means for synthesizing controller gains that minimize a weighted combination of the infinite norm of the sensitivity function (for disturbance attenuation requirements) and complementary sensitivity function (for robust stability requirements) at the same time. The case study deals with a complete full-authority longitudinal control system for an unstable high-performance jet aircraft featuring (i) a stability and control augmentation system and (ii) autopilot functions (speed and altitude hold). Constraints on closed-loop response are enforced, that representing typical requirements on airplane handling qualities, that makes the control law synthesis process more demanding. Gain scheduling is required, in order to obtain satisfactory performance over the whole flight envelope, so that the synthesis is performed at different reference trim conditions, for several values of the dynamic pressure, used as the scheduling parameter. Nonetheless, the dynamic behaviour of the aircraft may exhibit significant variations when flying at different altitudes, even for the same value of the dynamic pressure, so that a trade-off is required between different feasible controllers synthesized at different altitudes for a given equivalent airspeed. A multiobjective search is thus considered for the determination of the best suited solution to be introduced in the scheduling of the control law. The obtained results are then tested on a longitudinal non-linear model of the aircraft

    The Univariate Marginal Distribution Algorithm Copes Well With Deception and Epistasis

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    In their recent work, Lehre and Nguyen (FOGA 2019) show that the univariate marginal distribution algorithm (UMDA) needs time exponential in the parent populations size to optimize the DeceptiveLeadingBlocks (DLB) problem. They conclude from this result that univariate EDAs have difficulties with deception and epistasis. In this work, we show that this negative finding is caused by an unfortunate choice of the parameters of the UMDA. When the population sizes are chosen large enough to prevent genetic drift, then the UMDA optimizes the DLB problem with high probability with at most λ(n2+2elnn)\lambda(\frac{n}{2} + 2 e \ln n) fitness evaluations. Since an offspring population size λ\lambda of order nlognn \log n can prevent genetic drift, the UMDA can solve the DLB problem with O(n2logn)O(n^2 \log n) fitness evaluations. In contrast, for classic evolutionary algorithms no better run time guarantee than O(n3)O(n^3) is known (which we prove to be tight for the (1+1){(1+1)} EA), so our result rather suggests that the UMDA can cope well with deception and epistatis. From a broader perspective, our result shows that the UMDA can cope better with local optima than evolutionary algorithms; such a result was previously known only for the compact genetic algorithm. Together with the lower bound of Lehre and Nguyen, our result for the first time rigorously proves that running EDAs in the regime with genetic drift can lead to drastic performance losses

    Complex Lithofacies Relationships between the Ste. Genevieve and Paoli Limestones: Clarifying Reservoir Relationships in the Indiana Subsurface

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    This poster was presented at the American Association of Petroleum Geologists (AAPG) Eastern Section Meeting in Evansville, Indiana,on September 22, 2009.Typically irregular vertical and lateral distribution of lithofacies within the Ste. Genevieve and Paoli Limestones (Mississippian Blue River Group) has historically resulted in the inaccurate correlation of uppermost Ste. Genevieve lithologies (Joppa Member) with Paoli units of similar composition and appearance (Aux Vases and Renault Members). The Joppa Member of the Ste. Genevieve thins northeastward toward the Illinois Basin margin, losing the distinctive log signature that characterizes this unit in more basinward locations. The Aux Vases and Renault Members of the Paoli Limestone also become difficult to distinguish from each other and from the Joppa Member in basin margin locations because of rapid changes in composition and bed distribution. As a consequence, many Ste. Genevieve and Paoli Limestone pay zones have been assigned to the wrong reservoir pool, sometimes within the same field. Pay zones from Ste. Genevieve and Paoli Limestone reservoirs were reassigned according to current stratigraphic divisions. These new correlations more accurately reflect spatial relationships within and between hydrocarbon pools, and could contribute to more effective reservoir management. Improved correlations should also provide a useful tool for future hydrocarbon exploration and development activities in Indiana. Our investigation also suggests that revisions to formal Ste. Genevieve-Paoli stratigraphic nomenclature should be considered

    A Classification of Countable Lower 1-transitive Linear Orders

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    This paper contains a classification of countable lower 1-transitive linear orders. This is the first step in the classification of countable 1-transitive trees given in Chicot and Truss (2009): the notion of lower 1-transitivity generalises that of 1-transitivity for linear orders, and it is essential for the structure theory of 1-transitive trees. The classification is given in terms of coding trees, which describe how a linear order is fabricated from simpler pieces using concatenations, lexicographic products and other kinds of construction. We define coding trees and show that a coding tree can be constructed from a lower 1-transitive linear order (X,≤) by examining all the invariant partitions on X. Then we show that a lower 1-transitive linear order can be recovered from a coding tree up to isomorphism
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