工程控制网最优观测值的选取

为了解决测站平差方法中含大误差观测数据污染小的观测结果问题,从重复观测数据的实际特性出发,对观测量重复基本观测的多组观测值计算条件闭合差,从中选择一定数量的较小者对应的那些观测值组合进行平差计算,选择最小的那组,即获得最优观测值。通过漠拟算例进行验证,结果表明,新方法提高了平差结果的可靠性。     

数据的剔除对缺落值模型的影响

从距离角度和效率角度研究了一组数据和多组数据缺落值估计的影响,建立了剔除一组数据时Cook距离与复相关系数的等式关系,剔除多组数据时Cook距离与广义相关系数的不等式及广义方差比度量与Hoetelling广义相关系数的等式关系.     

镁合金循环塑性变形行为的实验和本构关系研究综述

Fatigue analysis has always been a concern in the design and assessment of Mg alloy structure components subjected to cyclic loading, and research on the cyclic plasticity is fundamental to investigate the corresponding fatigue failure. Thus, this work reviews the progress in the cyclic plasticity of Mg alloys. First, the existing macroscopic and microscopic experimental results of Mg alloys are summarized. Then, corresponding macroscopic phenomenological constitutive models and crystal plasticity-based models are reviewed. Finally, some conclusions and recommended topics on the cyclic plasticity of Mg alloys are provided to boost the further development and application of Mg alloys.     

Asymptotic Behavior of the Drift Coefficient Estimator of Stochastic Differential Equations Driven by Small Noises

The parametric estimation problem for diffusion processes with small white noise based on continuous time observations is well developed. However,in parametric inference,it is more realistic and interesting to consider asymptotic estimation for diffusion processes based on discrete observations. The least squares method is used to obtain the estimator of the drift parameter for stochastic differential equations( SDEs) driven by general Lévy noises when the process is observed discretely. Its strong consistency and the rate of convergence of the squares estimator are studied under some regularity conditions.     

我国农村贫困度的测算

本文论述贫困测度问题, 讨论了穷人比例、总收入缺口、森贫困测度等指标的合理性。论文提出一种由分组数据测算贫困度的方法, 并利用这种方法测算我国农村近年来的贫困度。     

中国美叶藻属（红藻门,楷模藻科）新种——扇形美叶藻（Callophyllis flabelliforma H.W.Wang sp. nov.）

对采自于辽宁省东港市大鹿岛的美叶藻属海藻的外部形态、内部结构进行了详细观察,并对rbcL基因序列进行了分析.结果表明：（1）藻体直立、膜质、叉状或掌状分枝,边缘全缘偶有微波状,基部生有圆柱状的直立短柄;（2）果胞枝由2～5个细胞组成,无分枝,受精后产孢丝形成卵形囊果,果孢子囊团被不育丝分隔,产孢丝单侧突出;（3）rbcL基因序列分析表明样本LNU20091105、LNU20091106与美叶藻属内其他种间的碱基差异为5.1%～7.6%（27～66bp）,为属内种间差异.在系统树中这2个样本也聚集为美叶藻属内一个单独的进化枝.据此我们认为该海藻是美叶藻属一个新种,命名为扇形美叶藻（Callophyllis flabelliforma H.W.Wang sp.nov.）.     

大中型兽类踪迹在野外考察及研究中的应用

在野外兽类考察过程中，由于多数兽类喜欢展昏活动或昼伏夜出，加上一些外界因素的影响，工作人员要对兽类进行直接的目的性观察和持续性研究有一定的难度．但由于动物的某些生物学特性，不同兽类的活动会在野外留下特定的踪迹，这为野外鉴别、观察和研究提供了重要的线索．本文总结了影响对大中型兽类进行直接性观察的因素、野外兽类踪迹的表现形式以及兽类的野外遗留物在有关研究中的应用，以期为野外考察与研究提供一定帮助．     

李安宅边疆思想要略

著名社会学家李安宅是我国近代边疆研究的重要代表人物。他长期致力于边疆史地宗教等方面的研究,在许多著述里全面系统地阐释了其边疆思想。其边疆思想着眼于“实地研究,”寄托了强烈的现实主义关怀。文章认为李安宅的边疆思想与其学科背景、边疆研究经历及抗战建国的时代背景密切相关。     

现代控制理论在反应堆功率调节中的应用

本文建立了反应堆功率调节系统的状态方程,运用现代控制理论中微分几何理论对非线性核动力学模型进行线性化处理,根据观察器理论,构造了状态变量C的观察器,研究了在反应堆功率和反应性两种扰动下反应堆全反馈功率调节系统的品质。研究结果表明,与经典的反应堆功率调节系统相比,采用全反馈的功率调节系统的动态品质可获得明显的提高。     

Forecasting non-seasonal time series with missing observations

Most forecasting methods are based on equally spaced data. In the case of missing observations the methods have to be modified. We have considered three smoothing methods: namely, simple exponential smoothing; double exponential smoothing; and Holt's method. We present a new, unified approach to handle missing data within the smoothing methods. This approach is compared with previously suggested modifications. The comparison is done on 12 real, non-seasonal time series, and shows that the smoothing methods, properly modified, usually perform well if the time series have a moderate number of missing observations.