258 research outputs found

    Tutorial on machine learning and data mining

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    The ability to learn from observations and to modify our understanding of the world based on experience is an essential aspect of intelligent behavior. Machine learning has thus become an important sub-area of artificial intelligence research and has yielded a number of interesting results about how it is possible to build computer systems that learn as well as insights into the process of learning. In addition, many new technologies have been developed which have been applied in the area of automatic learning from large databases. Searching large databases for hidden relationships is the focus of the new area known as data mining, which is being applied increasingly to search large databases for bidden nuggets of information. In this tutorial we will quickly introduce the related fields of machine learning and data mining. The tutorial will run for two hours. The first hour will be an introduction to machine learning, and the second will be a more in depth look at induction and data mining and how these fields extend from machine learning

    Asymptotics for Sobolev orthogonal polynomials for exponential weights

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    38 pages, no figures.-- MSC2000 codes: 42C05, 33C25.MR#: MR2164139 (2006c:41040)Zbl#: Zbl 1105.42016^aLet λ>0,α>1\lambda >0,\alpha >1, and let W(x)=exp(xα)W( x) =\exp ( -\vert x\vert ^{\alpha }) , x\in \mbox{\smallbf R}. Let \psi \in L_{\infty }(\mbox{\smallbf R}) be positive on a set of positive measure. For n1n\geq 1, one may form Sobolev orthonormal polynomials (qn)( q_{n}) , associated with the Sobolev inner product ( f,g) =\int_{\mbox{\scriptsize\bf R}}fg( \psi W) ^{2}+\lambda \int_{\mbox{\scriptsize\bf R}}f^{\prime }g^{\prime }W^{2}. We establish strong asymptotics for the (qn)( q_{n}) in terms of the ordinary orthonormal polynomials (pn)( p_{n}) for the weight W2W^{2}, on and off the real line. More generally, we establish a close asymptotic relationship between (pn)( p_{n}) and (qn)( q_{n}) for exponential weights W=exp(Q)W=\exp ( -Q) on a real interval II, under mild conditions on QQ. The method is new and will apply to many situations beyond that treated in this paper.The work by F. Marcellan has been supported by Dirección General de Investigación (Ministerio de Ciencia y Technología) of Spain under grant BFM 2003-06335-C03-07, as well as NATO Collaborative grant PST.CLG 979738. J. Geronimo and D. Lubinsky, respectively, acknowledge support by NSF grants DMS-0200219 and DMS-0400446.Publicad

    Finite dimensional quantizations of the (q,p) plane : new space and momentum inequalities

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    We present a N-dimensional quantization a la Berezin-Klauder or frame quantization of the complex plane based on overcomplete families of states (coherent states) generated by the N first harmonic oscillator eigenstates. The spectra of position and momentum operators are finite and eigenvalues are equal, up to a factor, to the zeros of Hermite polynomials. From numerical and theoretical studies of the large NN behavior of the product λ_m(N)λ_M(N)\lambda\_m(N) \lambda\_M(N) of non null smallest positive and largest eigenvalues, we infer the inequality δ_N(Q)Δ_N(Q)=σ_NN<2π\delta\_N(Q) \Delta\_N(Q) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi (resp. δ_N(P)Δ_N(P)=σ_NN<2π\delta\_N(P) \Delta\_N(P) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi ) involving, in suitable units, the minimal (δ_N(Q)\delta\_N(Q)) and maximal (Δ_N(Q)\Delta\_N(Q)) sizes of regions of space (resp. momentum) which are accessible to exploration within this finite-dimensional quantum framework. Interesting issues on the measurement process and connections with the finite Chern-Simons matrix model for the Quantum Hall effect are discussed

    Non-normality of continued fraction partial quotients modulo q

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    It is well known that almost all real numbers (in the sense of Lebesgue measure) are normal to base q where q ≥ 2 is any integer base

    Ewens measures on compact groups and hypergeometric kernels

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    On unitary compact groups the decomposition of a generic element into product of reflections induces a decomposition of the characteristic polynomial into a product of factors. When the group is equipped with the Haar probability measure, these factors become independent random variables with explicit distributions. Beyond the known results on the orthogonal and unitary groups (O(n) and U(n)), we treat the symplectic case. In U(n), this induces a family of probability changes analogous to the biassing in the Ewens sampling formula known for the symmetric group. Then we study the spectral properties of these measures, connected to the pure Fisher-Hartvig symbol on the unit circle. The associated orthogonal polynomials give rise, as nn tends to infinity to a limit kernel at the singularity.Comment: New version of the previous paper "Hua-Pickrell measures on general compact groups". The article has been completely re-written (the presentation has changed and some proofs have been simplified). New references added

    Theory of random matrices with strong level confinement: orthogonal polynomial approach

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    Strongly non-Gaussian ensembles of large random matrices possessing unitary symmetry and logarithmic level repulsion are studied both in presence and absence of hard edge in their energy spectra. Employing a theory of polynomials orthogonal with respect to exponential weights we calculate with asymptotic accuracy the two-point kernel over all distance scale, and show that in the limit of large dimensions of random matrices the properly rescaled local eigenvalue correlations are independent of level confinement while global smoothed connected correlations depend on confinement potential only through the endpoints of spectrum. We also obtain exact expressions for density of levels, one- and two-point Green's functions, and prove that new universal local relationship exists for suitably normalized and rescaled connected two-point Green's function. Connection between structure of Szeg\"o function entering strong polynomial asymptotics and mean-field equation is traced.Comment: 12 pages (latex), to appear in Physical Review

    Some extremal functions in Fourier analysis, III

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    We obtain the best approximation in L1(R)L^1(\R), by entire functions of exponential type, for a class of even functions that includes eλxe^{-\lambda|x|}, where λ>0\lambda >0, logx\log |x| and xα|x|^{\alpha}, where 1<α<1-1 < \alpha < 1. We also give periodic versions of these results where the approximating functions are trigonometric polynomials of bounded degree.Comment: 26 pages. Submitte

    Introduction to Random Matrices

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    These notes provide an introduction to the theory of random matrices. The central quantity studied is τ(a)=det(1K)\tau(a)= det(1-K) where KK is the integral operator with kernel 1/\pi} {\sin\pi(x-y)\over x-y} \chi_I(y). Here I=j(a2j1,a2j)I=\bigcup_j(a_{2j-1},a_{2j}) and χI(y)\chi_I(y) is the characteristic function of the set II. In the Gaussian Unitary Ensemble (GUE) the probability that no eigenvalues lie in II is equal to τ(a)\tau(a). Also τ(a)\tau(a) is a tau-function and we present a new simplified derivation of the system of nonlinear completely integrable equations (the aja_j's are the independent variables) that were first derived by Jimbo, Miwa, M{\^o}ri, and Sato in 1980. In the case of a single interval these equations are reducible to a Painlev{\'e} V equation. For large ss we give an asymptotic formula for E2(n;s)E_2(n;s), which is the probability in the GUE that exactly nn eigenvalues lie in an interval of length ss.Comment: 44 page
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