What is a latent variable? • A variable that is not observable or is not directly measurable. • A variable that is measured with error or can only be measured with error. • A latent variable can be used to represent a 'true' variable which is measured with error, OR a single conceptual variable, OR a construct which is a summarization of a complex concept. Examples of 'true' variables that are ...

Measurement error data or errors-in-variable data are often collected in many studies. Natural criterion functions are often unavailable for general functional measurement error models due to the lack of information on the distribution of the unobservable covariates. Typically, the parameter estimation is via solving estimating equations. In addition, the construction of such estimating equatio...

Energy delivery at well construction in regions with hard climate is distinguished by variable demand in electric and heat power. Energy consumption of drilling equipment, production and living facilities varies greatly during the year, depending on power load charts and climate conditions. Power supply of remote well construction sites is mostly accomplished by operating autonomous power sourc...

We show that the nondemolition measurement of a spacelike Wilson loop operator W (C) is impossible in a relativistic non-Abelian gauge theory. In particular, if two spacelikeseparated magnetic flux tubes both link with the loop C, then a nondemolition measurement of W (C) would cause electric charge to be transferred from one flux tube to the other, a violation of relativistic causality. A dest...

We show that the nondemolition measurement of a spacelike Wilson loop operator W(C) is impossible in a relativistic non-Abelian gauge theory. In particular, if two spacelike-separated magnetic flux tubes both link with the loop C, then a nondemolition measurement of W(C) would cause electric charge to be transferred from one flux tube to the other, a violation of relativistic causality. A destr...

The current surge of interest in multiferroic materials demands specialized measurement techniques to support multiferroics research. In this review article we detail well-established measurement techniques of the magneto-electric coupling coefficient in multiferroic materials, together with newly proposed ones. This work is intended to serve as a reference document for anyone willing to develo...