The surface shape and optical quality of the solar concentrators have a great influence on the solar power plant efficiency, and there need an accurate, inexpensive and fast tool to do this measurement work at the plant start up and during operation. The development of the measurement methods of...

The simultaneous and nonparametric estimation of latent abilities and item characteristic curves is considered. In particular, the joint asymptotic properties of ordinal ability estimation and kernel smoothed nonparametric item characteristic curve estimation is investigated under relatively...

According to the weak local independence approachto defining dimensionality, the fundamental quantitiesfor determining a test’s dimensional structure are the covariancesof item-pair responses conditioned on examineetrait level. This paper describes threedimensionality...

It has long been part of the Item Response Theory (IRT) folklore that under the usual empirical Bayes unidimensional IRT modeling approach, the posterior distribution of examinee ability given test response is approximately normal for a long test. Under very general non-parametric assumptions,...

A statistical test of the unidimensionality of the parameter underlying independent non-identically distributed Bernoulli trials is proposed and large sample results are derived. The procedure has applications in psychometry and hopefully other applied disciplines.