Testing for the usefulness of forecasts

Ashley (Journal of Forecasting 1983; 2 (3): 211–223) proposes a criterion (known as Ashley's index) to judge whether the external macroeconomic variables are well forecast to serve as explanatory variables in forecasting models, which is crucial for policy makers. In this article, we try to extend Ashley's work by providing three testing procedures, including a ratio‐based test, a difference‐based test, and the Bayesian approach. The Bayesian approach has the advantage of allowing the flexibility of adapting all possible information content within a decision‐making environment such as the change of variable's definition due to the evolving system of national accounts. We demonstrate the proposed methods by applying six macroeconomic forecasts in the Survey of Professional Forecasters. Researchers or practitioners can thus formally test whether the external information is helpful. Copyright © 2010 John Wiley & Sons, Ltd.     

S－2型空气SO_2无动力采样器

Ｓ－２型空气ＳＯ＿２无动力采样器杜尧国，王勇，徐自力，李绍民，田星叶（吉林大学环境科学系长春１３００２３）关键词无动力采样器，二氧化硫，扩散式Ｓ－２型空气ＳＯ＿２无动力采样器克服了Ｓ－１型在隆冬季节测得值偏低较多，空白吸光度偏高且不易稳定控制而导致检...     

吉布斯自由能图在水溶液体系中的扩展

本文提出了一种用于水溶液热力学计算的图解法,并详细阐述了这种图解法的作图原理、用途和使用方法.这种图解法是对吉布斯图的一种发展.     

吉布斯自由能与植物中水份运输

介绍了吉布斯自由能 ,及其与水势的关系 ,分析了水势、重力势、压力势在植物体内、外水份运输过程中的作用     

论自发过程

用熵增原理分析讨论了对自发过程的各种现行叙述法和定义,给出了自发过程的严格定义,分析了自由能判据和自由焓判据的实质.     

化学势相关问题的剖析和讨论

文章根据全微分和欧拉定理，分析了关于化学势在不同状态参量情况下的各种推导，讨论了化学势的定义式；结合吉布斯函数判据和广义功的方法，分析了相变过程，讨论了吉布斯函数的物理意义。     

利用神经网络算法推算超额吉布斯自由能

利用神经网络算法推算了超额吉布斯自由能Gm^E，并将推算结果与实验结果进行了比较，推算的平均相对误差均在1．42％以内。     

A new texture analysis approach

A new texture analysis approach by using Gibbs random field model is discussed. A parameter vector is defined in order to compute potentials of textures. It is found that texture features can be provided by its corresponding parameter vector, and the vector can be estimated in terms of maximum potential. Conclusions can be inferred that this new method based on the maximum potential is valid. Supported by the National Natural Science Foundation of China Zhang Zhan: born in 1971, Ph. D. graduate student