Reliability and Survival Analysis for Drifting Markov Models: Modeling and Estimation

Methodology and Computing in Applied Probability - In this work we focus on multi-state systems modeled by means of a particular class of non-homogeneous Markov processes introduced in Vergne (Stat...     

A Modification of an Algorithm by Golub and Plemmons for Large Linear Least Squares in the Context of Doppler Positioning

This paper considers the solution of the geodetic Doppler multi-stationadjustment, i.e. the problem of computing the positions of severalstations observing the Doppler shift on radio frequencies emittedby several artificial satellites passing over the horizon. Amodification of an algorithm due to Golub and Plemmons, forsolving large linear least-squares problems where the observationmatrix has a block dual angular form, is proposed in this framework.This modification is shown to reduce substantially both datatransfer between the tracking stations and the main computingcentre, and the total computational effort required to obtainthe solution of the problem. Preliminary numerical results arediscussed and some further comments presented.     

Square roots of elliptic second order divergence operators on strongly lipschitz domains:<Emphasis Type="Italic">L</Emphasis><Superscript>2</Superscript> theory

We prove the Kato conjecture for square roots of elliptic second order non-self-adjoint operators in divergence formL = -div(A∇) on strongly Lipschitz domains in ℝⁿ, n≥2, subject to Dirichlet or to Neumann boundary conditions. The method relies on a transference procedure from the recent positive result on ℝⁿ in [2].     

Determination of trace elements in archaeological ceramics and application of Kernel Density Estimates: Implications for the definition of production locations

Summary Chemistry fingerprint of materials helps determine provenance and technological production techniques, and, therefore, is useful way to study interaction between prehistoric people. In this work 38 ceramic fragments from Justino and S?o José sites, in Brazilian northeast, were analyzed using instrumental neutron activation analysis (INAA). The recognition of the compositionally homogeneous group within of the database was performed by means of principal component (PC). The PC scores were calculated on the matrix covariance of the log base 10 transformed concentration values, and grouping was sought in the PC scores using Kernel Density Estimates (KDE). By using KDE from PC scores two chemically different groups were found. Discriminant analysis was performed to assess the groups' validity. Despite of the pottery from Justino and S?o José sites present same technical profile, different of the Tupiguarani and Aratu traditions, it was obtained that Justino and S?o José samples are constitute of distinct ceramic pastes. This result can be understood in terms of the cultural influences in the preparation of the ceramic past and that potteries analyzed are originate locally.     

The multiplicities of the equivariant index of twisted Dirac operators

In this note, we give a geometric expression for the multiplicities of the equivariant index of a Dirac operator twisted by a line bundle.