-
作者：DIETRICH, CR
摘要：Numerical simulations recently reported in the literature have shown that the profile likelihood associated with the estimation of covariance range parameters for a Gaussian field can be multimodal. Here we complement these recent results by considering covariances with unknown nugget, scale and range parameters. Estimation is performed in a restricted maximum likelihood framework. For unbounded sampling domains and known range parameter, conditions ensuring asymptotic unimodality of the restr...
-
作者：CHIU, ST
摘要：It is well known that the cross-validation score function of discretized data often tends to - infinity as the bandwidth tends to zero. This disturbing property causes some difficulty in applying cross-validation to discretized data. Since all data are rounded to some degree, the phenomenon limits the application of cross-validation in practice. Based on characteristic functions, the cause of the difficulty is explained, and a simple modification is suggested. Under some conditions, it is show...
-
作者：HIROTSU, C
摘要：A mixed effects model is assumed for comparing treatments based on repeated measurements. The covariance structure of the data is interpreted as some systematic inhomogeneity of individual profiles along the time axis, rather than as serial correlation. Then a method of comparing treatment effects is proposed as well as that of testing the homogeneity of individual profiles. A follow-up analysis of residuals for the resulting model is also mentioned.
-
作者：OGATA, Y; KATSURA, K
摘要：Two approximate maximum likelihood estimates of the fractal dimension are suggested for random point patterns and planar curves, based on the distributions of the Palm probability and the spectrum.
-
作者：CORMACK, RM; JUPP, PE
摘要：Capture-recapture models have been formulated both as Poisson and as multinomial distributions. Maximum likelihood estimates of parameters under the two models are compared. For parameters which do not involve the population size the asymptotic covariances are shown to be the same.
-
作者：LIN, DY
摘要：This paper addresses sequential testing in randomized clinical trials with multiple endpoints. Patients enter treatments serially and are subject to random loss to followup. The endpoints of interest may be time-to-event variables or other quantitative measurements. The proposed test statistic at a given look is a weighted sum of the linear rank statistics with respect to the marginal distributions of the multiple endpoints. The weights can be chosen to maximize asymptotic power against certai...
-
作者：YATRACOS, YG
摘要：The efficiency of an estimate S(n) is usually computed at some underlying distribution. Because it is rare that a real situation can be represented by a single assumed model, Tukey proposed to compute instead the polyefficiency of S(n), that is the infimum of the efficiencies of S(n) at a reasonable collection of distributions called corners. It is shown that high polyefficiency over a finite number of corners, seen as possible distributions of the n dimensional sample, implies at least as hig...
-
作者：NAYAK, TK
摘要：We consider a superposition of an unknown number of independent homogeneous Poisson processes with unknown rates and suppose that when an event occurs, the component process in which it occurred can be identified. The number of component processes and their rates are to be estimated by observing the system for some time. In the general case, it is difficult to estimate all of the parameters but we derive the best unbiased estimators of some parametric functions. Inferences for the special case...
-
作者：JENSEN, ST; JOHANSEN, S; LAURITZEN, SL
作者单位：Aalborg University
摘要：In this paper we show global convergence, under very general assumptions, of iterative maximization procedures with cyclic fixing of groups of parameters, maximizing over the remaining parameters. Further we show that a slightly modified Newton procedure applied to the derivative of the reciprocal likelihood function in a one-dimensional exponential family, is globally convergent. We also prove that if the distribution of the sufficient statistic is infinitely divisible, then the Newton method...
-
作者：FRISEN, M; DEMARE, J
作者单位：Chalmers University of Technology
摘要：Continual surveillance to detect some event is of interest in quite different situations in industry, medicine, economics and other fields. A general method with an optimality property is described. The implications of the method for some different situations are derived. Some commonly used methods turn out to be special cases.
