动态聚类方法在单指标专题要素分级中的应用

本文剖析了现有聚类分级方法的优劣,论述了应用动态聚类方法进行单指标专题要素分级的基本原理、方法、步骤;试验结果表明,动态聚类分级方法计算简单,占机容量小,具有较高分级精度,并可获得最优或次优分级方案.     

高速脱壳穿甲弹的中间弹道研究

该文以研究脱壳穿甲弹的中间弹道问题为主线,较详细地综述了高速脱壳穿甲弹穿越膛口中间弹道区时所受到的各种扰动因素、以及脱壳穿甲弹飞行姿态的测试技术和观察手段。扰动因素包括脱壳穿甲弹膛内运动时形成的起始偏角、在射流区受到的气动力干扰、脱壳过程的机械干扰及膛口装置的干扰。文末介绍了脱壳穿甲弹弹托的优化设计问题。     

单片机测速仪的设计和研制

本文介绍用测周法设计和研制出单片机测速仪的方法。该测速仪具有硬件电路简单,测速范围、测量精度及分辨力均高于目前转速表等优点。样机的试运行表明,这种测速装置已达实用阶段,具有推广价值。     

最合理的观测次数和奇异值的拉依达舍弃准则研究

本文论述了为达到一定实验精度所必需的最合理的观测次数,以及在应拉依达舍弃准则判断奇异值的取舍时,(σX)的计算方法。     

求解结构动力方程的高精度直接积分法

提出了一种构造高精度无条件稳定的积分格式方法，建立了具有三阶精度的无条件稳定直接积分法，既适用于比例阻尼体系，也适用于非比例阻尼体系。与以往的高精度方法相比，本文方法具有计算量少、存贮空间小的优点，而且没有超越现象。     

Forecasting us home sales using bvar models and survey data on households' buying attitudes for homes

This study uses Bayesian vector autoregressive models to examine the usefulness of survey data on households' buying attitudes for homes in predicting sales of homes. We find a negligible deterioration in the accuracy of forecasts of home sales when buying attitudes are dropped from a model that includes the price of homes, the mortgage rate, real personal disposable income, and die unemployment rate. This suggests that buying attitudes do not add much to the information contained in these variables. We also find that forecasts from the model that includes both buying attitudes and the aforementioned variables are similar to those generated from a model that excludes the survey data but contains the other variables. Additionally, the variance decompositions suggest that the gain from including the survey data in the model that already contains other economic variables is small.     

数字化地籍测图中界址点的测量精度分析

针对数字化地籍测图的特点,结合具体仪器,分析了界址点测量的误差来源,并就主要误差对其精度的影响做了探讨,提出了相应的措施.     

Evaluating the role judgment plays in forecast accuracy

The majority of model-based forecasting efforts today rely on relatively simple techniques of estimation and the subjective adjustment of the model's results to produce forecasts. Published forecasts reflect to a great extent the judgment of the forecaster rather than what the model by itself has to say about the future. This paper examines the role judgment plays in the process of producing a macroeconometric forecast. The debate over the use of adjustment constants to alter the statistical results of a model is outlined and an empirical analysis of forecasts generated by the Michigan Quarterly Econometric Model of the US economy is presented using a unique data set which isolates the role of judgment in the forecasting process.     

测量中易混淆的问题及数据的处理方法

以基本测量和衍射光栅实验为例,分别对等精度测量和不等精度测量的误差进行分析,阐述了数据处理方法,从而保证了实验数据的准确性和精确度.     

一种6-SPS并联机器人精度分析算法

通过对 6—SPS型并联机器人位置输入输出方程微分 ,分析并联机器人结构误差对机器人末端误差的影响 .当结构误差和末端误差都是微小量时 ,机器人误差模型为线性数学模型 ,仿真证实该算法可对 6—SPS并联机器人进行精度分析 .