background : gastric cancer is the one of the most prevalent reason of cancer-related death in the world. survival of patients after surgery involves identifying risk factors. there are various models to detect the effect of risk factors on patients’ survival. the present study aims at evaluating these models. methods : data from 330 gastric cancer patients diagnosed at the iran cancer institut...

wellbore instability is a quite common event during drilling, and causes many problems such as stuck pipe and lost circulation. it is primarily due to the inadequate understanding of the rock properties, pore pressure, and earth stress environment prior to well construction. this study aims to use the existing relevant logs, drilling, and other data from offset wells to construct a precise mech...

Wellbore stability analysis based on a new true-triaxial failure criterion i Abstract A main aspect of wellbore stability analysis is the selection of an appropriate rock failure criterion. The most commonly used criterion for brittle failure of rocks is the Mohr-Coulomb criterion. This criterion involves only the maximum and minimum principal stresses, σ 1 and σ 3 , and therefore assumes that ...

In this paper, noise enhanced detection is studied for M ary composite hypothesis-testing problems in the presence of partial prior information. Optimal additive noise is obtained according to two criteria, which assume a uniform distribution (Criterion 1) or the leastfavorable distribution (Criterion 2) for the unknown priors. The statistical characterization of the optimal noise has been obta...

In analogy with the periods of abelian integrals of differentials of the third kind for an elliptic curve defined over a number field, we introduce a notion of periods of the third kind for a rank 2 Drinfeld Fq[t]-module ρ defined over an algebraic function field. In this paper we establish explicit formulae for these periods of the third kind for ρ. Combining with the main result in [Chang-Pap...