Optimising and Non‐optimising Balance of Trade Models: A Comparative Evidence from India

This study estimates and compares the competing optimising and non‐optimising balance of trade models using Indian data. The results obtained from the optimising model suggest that the prices relative to user cost of capital and the real wealth lead to a deterioration, while the real capital stock results in an improvement in trade balance. The estimates of conventional non‐optimising balance of trade model show the significant effect of domestic income and real exchange rate and the insignificant effect of world income on the balance of trade. The error correction models reinforce the long run estimates and show the significant effect of lagged equilibria on the balance of trade. The non‐nested hypothesis tests provide mixed evidence for the preference of one model over the other. The J test suggests that the optimising model outperforms the non‐optimising model, while the F test shows that both these models are acceptable in explaining the balance of trade.     

运用删截卷积码实现不等错误保护

在数字通信系统中，发送的数据序列中的比特往往具有不等的重要性。为了寻求更可靠的信息传输，人们提出了一些不等错误保护（UEP）编码方案。本文介绍了一种通过删截卷积码（CC）实现UEP编码的方案，并通过仿真分析了该UEP编码的性能。仿真结果表明，运用删截卷积码实现的UEP编码能获得较好的性能。     

基于误差相关矩阵的交会定位误差评估方法

提出了采用误差相关矩阵对三站和多站交会定位误差评估方法，分析了该方法的实际应用。     

基于边际成本递增的多属性反向拍卖最优策略

针对当前传统的基于单一价格属性的逆向拍卖机制已难以满足企业日益复杂的采购需求的现状,需要研究采购环境下的多属性英式拍卖机制。首先,文中提出了基于边际成本递增的多属性拍卖模型。然后运用多属性效用理论,进一步研究了在多属性英式拍卖机制下投标人的最优投标策略及拍卖人最优评分规则。最后,基于边际成本递增的多属性拍卖模型,研究了不同因素及边际成本对拍卖人最优评分规则的影响。     

GPS卫星钟差二次多项式预报模型的总体最小二乘算法

GPS精密单点定位技术是今后GPS测量技术的发展趋势,其中,卫星轨道预报与钟差预报是该技术的关键。如今,IGS组织已能够提供短时高精度的卫星轨道预报,但在钟差预报方面尚无法达到实时定位的要求,所以建立足够精度的卫星钟差预报模型尤为重要。文章根据常用的二次多项式短期预报模型,提出新的参数估计方法——总体最小二乘估计,并得出该方法能进一步提高二次多项式模型预报精度的结论。     

天然气长输管道输差问题的分析与研究

针对目前天然气管输企业发展过程中存在的输差控制问题,采取有效措施建立天然气集输平衡与输差分析机制。讨论在当前技术及管理现状的条件下就输差、输差定位基础工作、输差分析与输差控制等问题,提出天然气输差控制理论和输差分析方法。     

经纬仪视准轴误差检验的几种方法及其区别

为了保证角度测量的精度,经纬仪的主要轴线(视准轴、水平轴、垂直轴)之间应满足一定的几何关系,其中视准轴与水平轴不正交,称之为视准轴误差,本文论述了视准轴误差检验的几种方法及区别。     

山东省经济增长与煤炭能源消费关系的实证研究

本文基于1990-2012的时序数列,利用协整分析、误差修正模型及格兰杰因果检验,实证检验了山东省经济增长与煤炭能源消耗之间的长期均衡和短期波动情况,并利用脉冲响应分析了两者的动态响应路径。     

Empirical prediction intervals revisited

Empirical prediction intervals are constructed based on the distribution of previous out-of-sample forecast errors. Given historical data, a sample of such forecast errors is generated by successively applying a chosen point forecasting model to a sequence of fixed windows of past observations and recording the associated deviations of the model predictions from the actual observations out-of-sample. The suitable quantiles of the distribution of these forecast errors are then used along with the point forecast made by the selected model to construct an empirical prediction interval. This paper re-examines the properties of the empirical prediction interval. Specifically, we provide conditions for its asymptotic validity, evaluate its small sample performance and discuss its limitations.