Correspondence on the selection of error measures for comparisons among forecasting methods

Clements and Hendry (1993) proposed the Generalized Forecast Error Second Moment (GFESM) as an improvement to the Mean Square Error in comparing forecasting performance across data series. They based their conclusion on the fact that rankings based on GFESM remain unaltered if the series are linearly transformed. In this paper, we argue that this evaluation ignores other important criteria. Also, their conclusions were illustrated by a simulation study whose relationship to real data was not obvious. Thirdly, prior empirical studies show that the mean square error is an inappropriate measure to serve as a basis for comparison. This undermines the claims made for the GFESM.     

Editorial

Systemic Practice and Action Research -     

Enhancing the process of methodology choice in total systems intervention (TSI) and improving chances of tackling coercion

The process of Choice in TSI is reexamined in this paper. Previously, methods² have been understood to have a given and immediate purpose and are employed when this is judged to be most suitable in the circumstances. In this paper we suggest that methods can be operated in ways that meet purposes not provided by their founding theoretical underpinnings. We develop this argument by pointing to cases where cybernetic or soft methods are driven by purposes and principles given to emancipatory methodology—in a quest to address more effectively issues of coercion. This may be necessary when explicit and direct employment of emancipatory methodology is not sensitive enough to political dynamics, where certain people may feel overly threatened by its language and consequently feel the need to subvert its use. We develop a defence for thisoblique use of cybernetic and soft methods in coercive contexts, and extend the argument to suggest that all methods can be employed in such a way.     

Editorial

Systemic Practice and Action Research -     

代数几何中的正定性Ⅱ向量丛和乘子理想的正定性

正定性是代数几何中的重要研究课题，本书系统地介绍了线丛、高阶向量丛、乘子理想的正定性的最新发展成果。全书共有三部分内容，分为两卷，本书为第二卷。第一卷含有第一部分内容，第二卷由第二部分和第三部分内容组成。     

Murine type C endogenous virus expression in murine 129 teratocarcinoma cell line]

Murine type C viral information is detectable in the cellular genome of both differentiated and undifferentiated cell lines derived from 129 Mouse teratocarcinoma. Cytoplasmic RNA expression which is negligible in differentiated cells, is significantly higher in multipotential undifferentiated cells. Furthermore it was observed that in vitro differentiation of multipotent cells leads to a decrease of this expression.