background: in order to assign appropriate planning target volume (ptv) margins, each centre should measure the patient positioning deviations for their set-up techniques. at the royal marsden hospital, uk, a conformal shell (cast) system is used when a stereotactic frame is not suitable. in this paper, we report on a series of measurements with the aim of obtaining the systematic and random co...

The treatment of systematic errors is often mishandled. This is due to lack of understanding and education, based on a fundamental ambiguity as to what is meant by the term. This note addresses the problems and offers guidance to good practice. 1 RIVAL DEFINITIONS: UNCERTAINTY AND MISTAKE 1.1 Random Uncertainties and Mistakes The word error is used in several ways. The everyday dictionary defin...

Reducing impacts of systematic errors in the observation data on inversing ecosystem model parameters using different normalization methods L. Zhang, M. Xu, M. Huang, and G. Yu Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing, China Received: 31 August 2009 – Accepted: 24 October 20...

goal: this study aims at analyzing and categorizing different grammatical errors including morpho-syntactic and syntactic errors in written narratives of mentally retarded students in tehran. the frequencies of errors are compared among students in different grades. method: descriptive-analytic method has been used. a test consisted of four picture stories have been administered to 125 students...