Diagnostic checks of non-standard time series models

Diagnostic checks have become a standard tool for helping to assess the adequacy of a forecasting system since Box and Jenkins' (1970) ARIMA modelling technique became popular. However, most of the research has developed checks for normal or second-order stationary models. This paper gives various diagnostic checks that can be performed simply on nonnormal, non-standard models such as the class of multiprocess models (Harrison and Stevens, 1976), where residuals are definitely not normal. The performance to date of these models can then be objectively scrutinized on-line. Examples, including a generalized cusum technique, are given to illustrate the effectiveness of the techniques on specific series.     

机械设备诊断策略的若干问题探讨

本文根据机械设备诊断问题的特点,深入讨论了机械设备诊断问题的概念体系,研究了机械设备诊断问题的知识策略和求解策略,提出了分析知识和基于知识的诊断环境等重要概念,并对其在诊断问题中的应用进行了探讨.     

历史上的问题与问题解决的教育功能

数学史的教育价值愈来愈受到教育界重视和认可．历史上的数学问题与问题解决作为数学史的重要组成部分,具有重要的教育功能．这些功能包括：激发学生的学习兴趣,改变学生的数学观;了解丰富的社会文化信息,加强学生的数学文化修养;展现解题方法的演变;体现深刻的数学思想方法等等．这些功能对于寓数学史于数学教育的实践有一定的借鉴和指导意义．