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1345 · Nov 201919922001200920172026
48 results for Spearman's rho

This paper proposes a new class of copulas which characterize the set of all twice continuously differentiable copulas. We show that our proposed new class of copulas is a new generalized copula family that include not only asymmetric copulas but also all smooth copula families available in the current literature. Spea…

2012-10-08abs ↗pdf ↗

We study the problem of rank aggregation: given a set of ranked lists, we want to form a consensus ranking. Furthermore, we consider the case of extreme lists: i.e., only the rank of the best or worst elements are known. We impute missing ranks by the average value and generalise Spearman's ρto extreme ranks. Our main …

2014-10-16abs ↗pdf ↗

This paper fills in local bounds for Spearman's footrule and Gini's gamma measures of association.

problem Local bounds for bivariate copulas with respect to Spearman's footrule and Gini's gamma measures.
method Computing quasi-copulas that are not copulas for certain values of the measures.
result Presented local bounds for Spearman's footrule and Gini's gamma measures.

We propose a semiparametric approach, named nonparanormal skeptic, for estimating high dimensional undirected graphical models. In terms of modeling, we consider the nonparanormal family proposed by Liu et al (2009). In terms of estimation, we exploit nonparametric rank-based correlation coefficient estimators includin…

2012-06-27abs ↗pdf ↗

Standardizes weighted ranking correlation coefficients to maintain zero expected value.

problem Measuring correlation between weighted rankings of items.
method Develops a standardization function g(·) that transforms coefficients to zero expected value under randomness.
result A general standardization function g(Γ) that preserves the domain [-1,1] and reduces to the identity for coefficients already satisfying zero-expected-value property.

Forest tree species mapped with high accuracy using satellite data.

problem Classifying dominant tree species in Swedish forests.
method Extreme gradient boosting model with Bayesian optimization, combining Sentinel-1/2 satellite data and field observations.
result Overall accuracy of 85%, F1 score of 0.82, Matthews correlation coefficient of 0.81.

New Hermite series estimator for Spearman rank correlation in non-stationary data.

problem Estimating time-varying Spearman rank correlation efficiently.
method Hermite series based sequential estimator for both stationary and non-stationary settings.
result Competitive performance compared to existing algorithms in simulations and real data.

In this paper, we propose a semiparametric approach, named nonparanormal skeptic, for efficiently and robustly estimating high dimensional undirected graphical models. To achieve modeling flexibility, we consider Gaussian Copula graphical models (or the nonparanormal) as proposed by Liu et al. (2009). To achieve estima…

2012-02-10abs ↗pdf ↗

Using adiabatic limits of Eta invariants, Rho invariants of the total space of a fiber bundle are investigated. One concern is to formulate the aspects of local index theory for families of Dirac operator in terms of the odd signature operator, and place known results in a context which permits the treatment of Rho inv…

2009-07-21abs ↗pdf ↗

Researchers develop a formula to calculate rho invariant of Dehn surgeries on links.

problem Exploring relationships between rho invariant and signatures of links.
method Developed a versatile cut-and-paste formula for the rho invariant.
result Found formulas expressing rho invariant of Dehn surgeries on links as a sum of multivariable signature and easy-to-compute terms.

Let G be a finitely generated discrete group. In this paper we establish vanishing results for rho-invariants associated to (i) the spin-Dirac operator of a spin manifold with positive scalar curvature (ii) the signature operator of the disjoint union of a pair of homotopy equivalent oriented manifolds with fundamental…

2004-07-22abs ↗pdf ↗

The equivariant rho-invariants studied in this paper are a version of the classical rho-invariants of Atiyah, Patodi, and Singer in the presence of an isometric involution. We compute these rho-invariants for all involutions on the 3-dimensional lens spaces with 1-dimensional fixed point sets, as well as for some invol…

2016-09-16abs ↗pdf ↗

This article is a follow up of the previous article of the authors on the analytic surgery of eta- and rho-invariants. We investigate in detail the (Atiyah-Patodi-Singer)-rho-invariant for manifolds with boundary. First we generalize the cut-and-paste formula to arbitrary boundary conditions. A priori the rho-invariant…

2002-03-11abs ↗pdf ↗

We study noncommutative eta- and rho-forms for homotopy equivalences. We prove a product formula for them and show that the rho-forms are well-defined on the structure set. We also define an index theoretic map from L-theory to C*-algebraic K-theory and show that it is compatible with the rho-forms. Our approach, which…

2010-08-21abs ↗pdf ↗

Let XX be a closed oriented connected topological manifold of dimension n5n\geq 5. The structure group of XX is the abelian group of equivalence classes of all pairs (f,M)(f, M) such that MM is a closed oriented manifold and f ⁣:MXf\colon M \to X is an orientation-preserving homotopy equivalence. The main purpose of this a…

2016-08-12abs ↗pdf ↗

We define the secondary invariants L^2- eta and -rho forms for families of generalized Dirac operators on normal coverings of fibre bundles. On the covering family we assume transversally smooth spectral projections, and Novikov--Shubin invariants bigger than 3(dim B+1) to treat the large time asymptotic for general op…

2007-04-06abs ↗pdf ↗

New metrics quantify implementation risk in portfolio backtesting, revealing systematic differences in engine implementations.

problem Systematic divergence in backtested portfolio metrics due to differences in engine implementations.
method Formalized implementation risk, proposed four metrics, executed 15 strategies through five engines, analyzed source-code defects.
result Implementation risk introduces measurable ambiguity in performance attribution, but does not alter investment decisions.

We investigate the relative information content of six measures of dependence between two random variables XX and YY for large or extreme events for several models of interest for financial time series. The six measures of dependence are respectively the linear correlation ρv+ρ^+_v and Spearman's rho ρs(v)ρ_s(v) conditio…

2002-03-07abs ↗pdf ↗

New method evaluates AI stock prediction systems based on decision-making processes.

problem Lack of evaluation for AI systems' decision-making processes.
method Scores intermediate decision process using large language models and closed-loop reinforcement learning feedback.
result Composite behavioral score correlates with Sharpe ratio and reduces prediction error.

We consider the set of solutions to the rho-vortex equations over a Kahler surface and prove a Uhlenbeck compactness result, namely that a sequence of solutions with the same energy converge to the sum of a solution of smaller energy and deltas of Dirac.

2004-06-29abs ↗pdf ↗

On a filtered probability space (Ω,F,P,F=(Ft)t=0,,T)(Ω,\mathcal{F},P,\mathbb{F}=(\mathcal{F}_t)_{t=0,\dotso,T}), we consider stopper-stopper games $\overline V:=\inf_{\Rho\in\bT^{ii}}\sup_{τ\in\T}\E[U(\Rho(τ),τ)]$ and $\underline V:=\sup_{\Tau\in\bT^i}\inf_{ρ\in\T}\E[U(\Rho(τ),τ)]$ in discrete time, where U(s,t)U(s,t) is $\mathcal{F}_{s\vee…

2014-08-16abs ↗pdf ↗

We show that if the connected sum of two knots with coprime Alexander polynomials has vanishing von Neumann rho-invariants associated with certain metabelian representations then so do both knots. As an application, we give a new example of an infinite family of knots which are linearly independent in the knot concorda…

2007-10-10abs ↗pdf ↗

We establish existence of the eta-invariant as well as of the Atiyah-Patodi-Singer and the Cheeger-Gromov rho-invariants for a class of Dirac operators on an incomplete edge space. Our analysis applies in particular to the signature, the Gauss-Bonnet and the spin Dirac operator. We derive an analogue of the Atiyah-Pato…

2016-04-25abs ↗pdf ↗

Paper introduces MVS to detect non-Markovian observations in reinforcement learning.

problem Real-world sensors violate Markov property, leading to suboptimal reinforcement learning performance.
method Uses prediction-based Markov Violation Score (MVS) combining random forest and ridge regression.
result MVS detects non-Markovian structure in observation trajectories, quantifying its impact.

For a closed, oriented, odd dimensional manifold XX, we define the rho invariant ρ(X,E,H)ρ(X,E,H) for the twisted odd signature operator valued in a flat hermitian vector bundle EE, where H=ij+1H2j+1H = \sum i^{j+1} H_{2j+1} is an odd-degree closed differential form on XX and H2j+1H_{2j+1} is a real-valued differential form of degree…

2012-02-01abs ↗pdf ↗

SBI provides more accurate pole positions than chi-squared minimization in model misspecification.

problem Accurate pole position estimation in pi-pi scattering models.
method Simulation Based Inference (SBI) method compared to chi-squared minimization.
result SBI leads to more robust predictions of pole positions in models of pi-pi scattering.

Let M be an orientable topological manifold of dimension m, m greater or equal to 5, with fundamental group ΓΓ. Let S(M) be the topological structure set, endowed with the group structure induced by its identification with Ranicki's algebraic structure set. We prove that the (rationalized) rho map $ρ_Γ: S(M)\rightarro…

2016-07-24abs ↗pdf ↗

We provide explicit, simple, geometric formulas for free involutions rho of Euclidean spheres that are not conjugate to the antipodal involution. Therefore the quotient S^n/rho is a manifold that is homotopically equivalent but not diffeomorphic to RP^n. We use these formulas for constructing explicit non-trivial eleme…

2005-01-06abs ↗pdf ↗

We study primary and secondary invariants of leafwise Dirac operators on foliated bundles. Given such an operator, we begin by considering the associated regular self-adjoint operator DmD_m on the maximal Connes-Skandalis Hilbert module and explain how the functional calculus of DmD_m encodes both the leafwise calculus…

2008-09-12abs ↗pdf ↗

In this paper, we study the space of metrics of positive scalar curvature using methods from coarse geometry. Given a closed spin manifold M with fundamental group G, Stephan Stolz introduced the positive scalar curvature exact sequence, in analogy to the surgery exact sequence in topology. It calculates a structure gr…

2012-10-25abs ↗pdf ↗