Showing papers by "University of Paris published in 1980"
TL;DR: In this paper, a method for computing all of the Lyapunov characteristic exponents of order greater than one is presented, which is related to the increase of volumes of a dynamical system.
Abstract: Since several years Lyapunov Characteristic Exponents are of interest in the study of dynamical systems in order to characterize quantitatively their stochasticity properties, related essentially to the exponential divergence of nearby orbits. One has thus the problem of the explicit computation of such exponents, which has been solved only for the maximal of them. Here we give a method for computing all of them, based on the computation of the exponents of order greater than one, which are related to the increase of volumes. To this end a theorem is given relating the exponents of order one to those of greater order. The numerical method and some applications will be given in a forthcoming paper.
1,659 citations
TL;DR: In this article, the authors present a detailed study of the methods of summation based on Borel transformation and conformal mapping, which have been used to calculate critical exponents of the $n$-vector model through field theoretical methods.
Abstract: We present a detailed study of the methods of summation based on Borel transformation and conformal mapping, which we have used to calculate critical exponents of the $n$-vector model through field theoretical methods. In particular we discuss the sensitivity of the results to various changes in the summation procedure.
1,123 citations
TL;DR: In this article, the authors give an explicit method for computing all Lyapunov Characteristic Exponents of a dynamical system, together with some numerical examples for mappings on manifolds and for Hamiltonian systems.
Abstract: The present paper, together with the previous one (Part 1: Theory, published in this journal) is intended to give an explicit method for computing all Lyapunov Characteristic Exponents of a dynamical system. After the general theory on such exponents developed in the first part, in the present paper the computational method is described (Chapter A) and some numerical examples for mappings on manifolds and for Hamiltonian systems are given (Chapter B).
896 citations
TL;DR: By including all types of secondary structure and by enlarging substantially the spectral region, the method permits analysis of the conformation of a variety of proteins, such as nucleic acid-binding proteins, immunoglobulins and β-pleated sheet-rich proteins.
751 citations
TL;DR: High-resolution determinations of crustal properties along the spreading center were made to gain knowledge of the source of new oceanic crust and marine magnetic anomalies, the nature of the axial magma chamber, and the depth of hydrothermal circulation.
Abstract: Hydrothermal vents jetting out water at 380° ± 30°C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits. Cooler springs are clear to milky and support exotic benthic communities of giant tube worms, clams, and crabs similar to those found at the Galapagos spreading center. Four prototype geophysical experiments were successfully conducted in and near the vent area: seismic refraction measurements with both source (thumper) and receivers on the sea floor, on-bottom gravity measurements, in situ magnetic gradiometer measurements from the submersible Alvin over a sea-floor magnetic reversal boundary, and an active electrical sounding experiment. These high-resolution determinations of crustal properties along the spreading center were made to gain knowledge of the source of new oceanic crust and marine magnetic anomalies, the nature of the axial magma chamber, and the depth of hydrothermal circulation.
687 citations
TL;DR: Comparison between the various groups shows that the best results were obtained in type II mitral incompetence, followed by type I and type III mitral incompetent, and predictable and stable long-term results have been achieved by techniques of valvular reconstruction with a low incidence of thromboembolism.
624 citations
TL;DR: In this article, it was shown that the anisotropy field maintaining the remanent magnetization in the direction of the initial applied field is strongly enhanced by the addition of nonmagnetic Au or Pt impurities.
Abstract: Recent measurements on $\mathrm{Cu}\mathrm{Mn}$ spin-glass alloys have revealed that the anisotropy field maintaining the remanent magnetization in the direction of the initial applied field is strongly enhanced by the addition of nonmagnetic Au or Pt impurities. We show that these results can be accounted for by the existence of Dzyaloshinsky-Moriya-type interactions between the Mn spins arising from spin-orbit scattering of the conduction electrons by nonmagnetic impurities. The magnitude of these interactions is surprisingly large.
566 citations
520 citations
TL;DR: In this article, the authors define the concept of "semi-presidential government" and detail the diversity of its practices, using four parameters: the content of the constitution, tradition and circumstances, the composition of the parliamentary majority and the position of the president in relation to the majority.
Abstract: This article aims at defining the concept of “semi-presidential government” and detailing the diversity of its practices. There are in fact three types of semi-presidential regimes: the president can be a mere figurehead, or he may be all-powerful or again he can share his power with parliament. Using four parameters — the content of the constitution, tradition and circumstances, the composition of the parliamentary majority and the position of the president in relation to the majority — the author seeks to explain why similar constitutions are applied in a radically different manner.
519 citations
TL;DR: In this paper, an unknown linear time-invariant system without control, driven by a white noise with known distribution, is considered, and the identification of both gain and phase of the system, observing only the output, is presented.
Abstract: Consider an unknown linear time-invariant system without control, driven by a white noise with known distribution. We are interested in the identification of this system, observing only the output. This problem is well known under the major assumption: the system is minimum (or maximum!) phase, in which the very popular least squares method gives an identification of the system in an autoregressive form. However, we are Interested in the case where the system is nonminimum (nor maximum!) phase, i.e., we want identification of both gain and phase of the system. The literature gives only a negative result: the idenfication of the phase of the system is impossible in the case of a Gaussian driving noise (hence, second-order statistics are irrelevant to our problem). For a large class of other input distributions, we present an identification procedure, and give some numerical results for a concrete case origin of our study: the blind adjustment of a transversal equalizer without any startup period prior to data transmission.
517 citations
TL;DR: In this paper, the latent hardening ratios (LHRs) were measured for different values of primary shear strain in Stage 1, and for various latent systems, including copper and aluminium single crystals.
TL;DR: In this article, a differentiation with respect to the domain in boundary value problems is presented, where the domain is defined as the domain of the boundary value problem and boundary value is defined.
Abstract: (1980). Differentiation with Respect to the Domain in Boundary Value Problems. Numerical Functional Analysis and Optimization: Vol. 2, No. 7-8, pp. 649-687.
TL;DR: In this paper, the theory of homogeneous redox catalysis in the context of cyclic voltammetry is presented for the EC reaction scheme, i.e., the simplest of the mechanisms in which the initial electron-transfer process is followed by chemical reaction.
TL;DR: In this paper, the authors reviewed the mechanics and physics of unstable, localized flow in simple shear with special reference to experimental results on materials, taking into account strain hardening or softening, strain-rate sensitivity and shear heating.
TL;DR: In this article, it is shown that the assumption of an unbounded time horizon along with (dated) commodities for each period suffices to render the First Theorem inapplicable to the general overlapping-generations model.
TL;DR: An attempt is made to explain how the complex and variable efferent activity can arise from an initially simple rhythmic command and produce the biomechanically adapted locomotor movement of the hindlimb.
TL;DR: A demonstration is given of the way in which a simple geometrical construction yields new and efficient algorithms for various searching and list manipulation problems.
Abstract: Examples of fruitful interaction between geometrical combinatorics and the design and analysis of algorithms are presented. A demonstration is given of the way in which a simple geometrical construction yields new and efficient algorithms for various searching and list manipulation problems.
TL;DR: In this paper, the authors studied the space BD(Ω), composed of vector functions u for which all components eij = 1/2(ui, j+uj, i) of the deformation tensor are bounded measures.
Abstract: We study the space BD(Ω), composed of vector functions u for which all components eij=1/2(ui, j+uj, i) of the deformation tensor are bounded measures. This seems to be the correct space for the displacement field in the problems of perfect plasticity. We prove that the boundary values of every such u are integrable; indeed their trace is in L1 (Γ)N. We show also that if a distribution u yields ɛij which are measures, then u must lie in Lp(Ω) for p≦N/(N−1).
TL;DR: In this article, the authors considered the problem of finding conditions on the quadratic variations of a local martingale sequence to insure its convergence towards a continuous Gaussian limit, where convergence in distribution is defined as the weak convergence of the (s sequence on the space D of right continuous and left hand limited functions.
Abstract: This paper is involved with the following problem. Given a sequence of local martingales, say (Mn), under which conditions on the quadratic variations ([M,]), can we state the convergence in distribution of the (M,) sequence towards a continuous gaussian martingale limit? "Convergence in distribution" means here the weak convergence of the (s sequence on the space D of right continuous and left hand limited functions, f ( M , ) being the probability measure induced on D by M n (i.e. the distribution or law of the M, process). In preceding works, the author has investigated an analogous problem for locally square integrable local martingales (in short, "locally square integrable martingales"). In such case we were interested in finding out conditions on the ( (M,)) sequence of associated increasing processes to insure the (M.)'s convergence in distribution. It is a well known fact (c.f. [-9]) that for a local martingale M the associated increasing process ( M ) exists if and only if M is locally square integrable. On the contrary, [M] always exists and, furthermore, [M] is easier to calculate than ( M ) when both processes exist. Thus the problem with which we will deal below is a very natural one. In the first paragraph, we will explain some notations. Paragraph two is devoted to state the main results of this paper. Proofs of these results are given in paragraph three. Paragraph four contains some particular cases of the main theorems. The last paragraph gives a complementary result for locally square integrabte martingales. The Appendix contains the recall of a classical Tightness Criterion used in the paper.
TL;DR: In this paper, the anodic oxidation of various monosubstituted aromatic amines has been grafted on Pt electrodes in a CH3CN−NaClO4-pyridine medium.
TL;DR: In this paper, it was shown that the restriction p > N / ( N 2 ) is essential, for if I < p < N/(N 2 ) there are solutions of (2) with isolated singularities.
Abstract: then there exists a C 2 function on f2 which coincides with u on f2'. In other words the equation (2) A u + l u f l u = O has the property that any isolated singularity is \"removable\". When p=(N+2)/(N-2) , this result is a consequence of a theorem of LOEWNER & NIRENBERG (see [2], Theorem 7). We note that the restriction p > N / ( N 2 ) is essential, for if I < p < N / ( N 2 ) there are solutions of (2) with isolated singularities (the full description of such singularities is discussed in [3]).
TL;DR: A catalog of historical seismicity from the VIIth to the XVIIIth century A.D. was compiled from Arabic documents (many of which are unpublished manuscripts) for the near and Middle East, and in a lesser measure, for North Africa and Spain this paper.
Abstract: A catalog of historical seismicity from the VIIth to the XVIIIth century A.D. was compiled from Arabic documents (many of which are unpublished manuscripts) for the near and Middle East, and in a lesser measure, for North Africa and Spain. In most cases, detailed descriptions have allowed us to assign Modified Mercalli intensities to the shocks for the localities where they were reported. The detailed chronology of a protracted episode of seismicity in northern Syria between 1156 and 1159 is given shock by shock from the relation of a Damascus chronicler.
TL;DR: In this article, a new and simpler proof of Rabinowitz's result was given for nontrivial time periodic solutions of a vibrating string equation uu - uxx + g(u) = 0 and Dirichlet boundary conditions on a finite interval.
Abstract: A new and simpler proof is given of the result of P. Rabinowitz for nontrivial time periodic solutions of a vibrating string equation uu - uxx + g(u) = 0 and Dirichlet boundary conditions on a finite interval. We assume essentially that g is nondecreasing, and g(u)/u∞ as |u|∞. The proof uses a modified form (PS)c of the Palais-Smale condition (PS).
TL;DR: In this paper, a von Neumann algebra in H is considered and each faithful weight ψ on M′ defines an operator-valued weight of L(H) on M. For each weight ϑ on M the positive unbounded operator dϑdψ = ϑ ∘ ψ−1 satisfies all the usual properties of a Radon-Nikodym derivative.
TL;DR: In this paper, the effects of influence attempts by a majority and by a minority were examined on both a manifest response level and a latent perceptual level, and it was predicted that the subject's judgment of the chromatic afterimage would be modified when the influence agent represented a minority.
TL;DR: In this paper, a classe de problemes non lineaires avec non linearite positive, croissante, convexe, and convexity is studied, and a discussion of partial differential equations is presented.
Abstract: (1980). Sur une classe de problemes non lineaires avec non linearite positive, croissante, convexe. Communications in Partial Differential Equations: Vol. 5, No. 8, pp. 791-836.
TL;DR: In this paper, the authors proved the existence and uniqueness of the solutions of the Cauchy problem with finite initial time, which implies the existence of the wave operators, and proved asymptotic completeness for a class of repulsive interactions.
Abstract: As regards the first question we prove existence and uniqueness of the solutions of the Cauchy problem with finite initial time; as regards the second one, we prove the existence of solutions of the Cauchy problem with infinite initial time, which implies the existence of the wave operators, and we prove asymptotic completeness for a class of repulsive interactions. The main reason for this investigation is that the Eq. (0.1) can be considered as the classical limit, in the field sense, of the field equation describing a