The modiied Newton-Sabatier method is extended to the inverse scattering problem of coupled channels at xed energy. The problem is solved for a system of coupled radial Schrr odinger equations with a potential matrix independent of the angular momentum of the relative motion. The new method is applied to the example of two channels coupled by complex-valued square well potentials. 1 Introductio...

in this study, a new reaction system for quantitative determination of ascorbic acid was introduced. the developed method is based on inhibitory effect of ascorbic acid on the orange g-bromate system. the change in absorbance was followed spectrophotometrically at 478 nm. the dependence of sensitivity on the reaction variables including reagents concentration, temperature and time was investiga...

In this dissertation we studied asymptotic properties of shrinkage estimators, and compared their performance with absolute penalty estimators (APE) in linear and partially linear models (PLM). A robust shrinkage M-estimator is proposed for PLM, and asymptotic properties are investigated, both analytically and through simulation studies. In Chapter 2, we compared the performance of shrinkage an...

The problem of parallelism for bi-linear regression lines arises in many real life investigations. For two linear regression models with normal errors, the estimation of the slope as well as the intercept parameters is considered when it is apriori suspected that the two lines are parallel. Three different estimators are defined by using both the sample data and the non-sample uncertain prior i...

The failure to detect anomalies and maneuvering of the orbits of navigation satellite sensors will deteriorate the performance of positioning and orbit determination. Motivated by the influence of the frequent maneuvering of BDS GEO and IGSO satellites, this paper analyzes the limitations of existing methods, where BDS orbit maneuvering and anomalies can be detected, and develops a method to so...

The ratio-type estimators have been introduced for estimating the mean and total population, but in recent years based on the ratio methods several estimators for population variance have been proposed. In this paper two families of estimators have been suggested and their approximation mean square error (MSE) have been developed. In addition, the efficiency of these variance estimators are com...

The problem of estimating large covariance matrices with use of factor models is addressed when both the sample size and the dimension of covariance matrix tend to infinity. In this paper, we consider a general class of weighted estimators which includes (i) linear combinations of the sample covariance matrix and the model-based estimator under the factor model and (ii) ridge-type estimators wi...

Imputation is one of the most common methods to reduce item non_response effects. Imputation results in a complete data set, and then it is possible to use naϊve estimators. After using most of common imputation methods, mean and total (imputation estimators) are still unbiased. However their variances (imputation variances) are underestimated by naϊve variance estimators. Sampling mechanism an...