北约体制的结构性缺陷与美欧的互动调整

北约体制是以美国为主导,以欧洲国家为主体,以欧洲安全事务为主要内容的结构形式,主导国家与主体国家的分离是形成结构性缺陷的根本原因。在冷战后成员利益出现分化时,这种缺陷凸显,井严重威胁到现行北约体制。为了维护北约体制的存续,美、欧双方基于自身利益和实力都进行了深刻地调整,并逐渐形成北约未来体制模式和制度框架。     

对公路雷达面层测厚的检验及评估测厚精度的方法

国内首次使用试验公路模型来检验探地雷达测厚的准确性,并提出雷达测厚精度的评价方法,为今后衡量雷达测厚精度的规范化提供依据.     

Unobserved components in ARCH models: An application to seasonal adjustment

The paper deals with unobserved components in ARIMA models with GARCH errors, in the context of an actual application, namely seasonal adjustment of the monthly Spanish money supply series. The series shows clear evidence of (moderate) non-linearity, which does not disappear with simple outlier correction. The GARCH structure explains reasonably well the non-linearity, and this explanation is robust with respect to the GARCH specification. We look at the time variation of the standard error of the adjusted series estimator and show how it can be measured. Next, we look at the implications this variation has on short-term monetary control. The non-linearity seems to have a small effect in practice. It is further seen that the conditional variance of the GARCH process may, in turn, be decomposed into components. In fact, the conditional variance of the money supply series is the sum of a weak linear trend, a strong non-linear seasonal component, and a moderate non-linear irregular component. This information has policy implications: for example, there are periods in the year when policy can be more assertive because information is more precise. Finally, looking at the non-linear components of the money supply it is seen how linear combinations of non-linear series can produce series that behave linearly.     

磨粒磨损机理与机油滤清器过滤精度选择

阐述了磨粒磨损破坏机理及不同磨粒尺寸与数量对磨损的影响,提出了我国新机油滤清器过滤性能评价方法及合理的滤清器精度选择范围.     

并联机床驱动杆铰链位置误差分析

为提高并联机床运动精度,解决其铰链误差对运动精度的影响问题,以东北大学开发的3-PTP并联机床为分析对象,采用叠加原理,建立三自由度并联机构驱动杆铰链误差模型;采用矩阵范数分析驱动杆铰链误差对动平台终端运动精度的影响规律.分析表明,结构参数λ大,不利于减小工作空间内动平台位置误差的最小值,但对其最大值影响不大.该误差模型的建立为此并联机床进一步优化机构设计参数以及误差补偿奠定了基础.     

砂轮约束磨粒喷射加工表面自相关性及功率谱分析

磨粒喷射精密光整加工是重要零件在磨削后进行去除表面缺陷层、降低粗糙度和波纹度为目的的光整加工新工艺.试验在M7120磨床上完成,加工试样为Ra=0.2~0.6μm的#45钢,加工表面形貌和微观几何参数用SEM和TR200表面轮廓仪测量.应用随机过程中的相关性从自相关、功率谱密度函数两方面对磨削表面和光整加工表面进行了研究.分析结果表明,该加工方法明显提高了工件的表面质量,降低了工件的表面粗糙度并均化了波纹度.     

变量施肥决策的多目标优化模型与算法

变量决策模型和优化算法是精准农业变量作业处方生成的核心环节.文中建立了一个综合考虑作物产量、质量、能源消耗、环境影响等多个指标的变量施肥多目标优化模型,提出了一种求解此类问题的高效禁忌搜索算法,从产量最大化的初始施肥方案出发,基于最近可行解的概念进行邻域搜索,并按照质量优先的策略不断寻找和更新解集,最后得到一组非支配意义下的优化施肥方案,以提高精准农业变量施肥的决策支持能力和水平.通过对江西宜春地区油茶树变量施肥问题的案例研究,验证了模型和算法的有效性和实用性.     

Forecasting with Micro Panels: The Case of Health Care Costs

Micro panels characterized by large numbers of individuals observed over a short time period provide a rich source of information, but as yet there is only limited experience in using such data for forecasting. Existing simulation evidence supports the use of a fixed‐effects approach when forecasting but it is not based on a truly micro panel set‐up. In this study, we exploit the linkage of a representative survey of more than 250,000 Australians aged 45 and over to 4 years of hospital, medical and pharmaceutical records. The availability of panel health cost data allows the use of predictors based on fixed‐effects estimates designed to guard against possible omitted variable biases associated with unobservable individual specific effects. We demonstrate the preference towards fixed‐effects‐based predictors is unlikely to hold in many practical situations, including our models of health care costs. Simulation evidence with a micro panel set‐up adds support and additional insights to the results obtained in the application. These results are supportive of the use of the ordinary least squares predictor in a wide range of circumstances. Copyright © 2016 John Wiley & Sons, Ltd.     

Periodic performance of the chaotic spreadspectrum sequence on finite precision

It is well known that the periodic performance of spread spectrum sequence heavily affects the correlative and secure characteristics of communication systems. The chaotic binary sequence is paid more and more attention since it is one kind of applicable spread spectrum sequences. However, there are unavoidable short cyclic problems for chaotic binary sequences in finite precision. The chaotic binary sequence generating methods are studied first. Then the short cyclic behavior of the chaotic sequences is analyzed in detail, which are generated by quantification approaches with finite word-length. At the same time, a chaotic similar function is defined for presenting the cyclic characteristics of the sequences. Based on these efforts, an improved method with scrambling control for generating chaotic binary sequences is proposed. To quantitatively describe the improvement of periodic performance of the sequences, an orthogonal estimator is also defined. Some simulating results are provided. From the theoretical deduction and the experimental results, it is concluded that the proposed method can effectively increase the period and raise the complexity of the chaotic sequences to some extent.     

基于模型概率的多模型融合定轨建模及仿真

针对实际定轨系统中存在的不确定性和非线性性,提出了一种基于模型概率的多模型融合定轨方法.通过多个线性模型的组合来逼近卫星定轨复杂非线性时变过程,将卫星状态的最优估计与多模型融合方法相结合,利用残差的大小来设计性能指标函数,给出了两种模型概率的表示形式,并建立了多模型融合估计相应的算法.仿真结果表明,与单一模型定轨方法相比,该方法不仅能大大提高卫星定轨精度和可靠性,而且还可以最终辨识和估计模型参数的真值,且对外界环境发生的变化有很强的自适应能力.