The Whittle Estimator for Strongly Dependent Stationary Gaussian Fields

In this article we generalize results on the asymptotic behaviour of the Whittle estimator for certain stationary Gaussian long range dependent fields. These results have been established in the one-dimensional case under very general conditions. They require controlling the estimation bias and also giving convergence theorems for certain quadratic forms of the observations. In the multidimensional setting, our main interest will be controlling the bias. This can be done for d ≤ 3 using taper functions, and, depending on the shape of the singularity, also introducing certain regularizing functions. In this last case, however, the estimator will no longer be efficient. We also present certain partial results concerning the convergence to a limiting Gaussian distribution of the associated quadratic forms.     

Bayesian analysis of agricultural field experiments

The paper describes Bayesian analysis for agricultural field experiments, a topic that has received very little previous attention, despite a vast frequentist literature. Adoption of the Bayesian paradigm simplifies the interpretation of the results, especially in ranking and selection. Also, complex formulations can be analysed with comparative ease, by using Markov chain Monte Carlo methods. A key ingredient in the approach is the need for spatial representations of the unobserved fertility patterns. This is discussed in detail. Problems caused by outliers and by jumps in fertility are tackled via hierarchical t formulations that may find use in other contexts. The paper includes three analyses of variety trials for yield and one example involving binary data; none is entirely straightforward. Some comparisons with frequentist analyses are made.     

对当前体育社会问题的思考

探讨当前主要存在的体育社会问题 ,以期引起体育主管部门和社会的关注及重视 ,为体育方针、政策、路线的制订提供参考依据 ,并希望有关部门采取有效措施 ,预防并杜绝这类问题的发生 ,使体育运动沿着正确轨道良性运行和健康发展     

国外电磁篱笆建设要素分析

日益增长的空间碎片对航天器和有限的轨道资源构成了严重的威胁,电磁篱笆是功率强大的地球中低轨道空间碎片监测设备.文中就国际上具有代表性的电磁篱笆,即美国和法国的电磁篱笆在建设过程中考虑的要素进行了详细分析,主要从地理位置、空域监视屏几何形状、性价比这3个方面因素进行了对比,并归纳了各自设计中的特点和优势.最后就国外电磁篱笆的发展趋势进行了分析和总结.     

纯电动汽车磁助力启动制动结构设计

根据纯电动汽车整丰在运行条件下制动力矩的需求，设计了一种磁助力启动制动系统。利用电磁同性相斥、异性相吸的原理，根据车轮速度时时变化控制和改变磁极磁性，在汽车起步和制动过程起到磁助力作用。计算了电磁启动制动力矩，设计了电磁制动控制电路。基于ECE法规设计了制动力分配算法，计算表明：在高响应测速传感器的反馈控刺中，磁动力启动制动结构能够迅速有效地起到助力作用，为改善纯电动汽车的行车效能提供了新的思路。     

Geostatistical Modelling Using Non‐Gaussian Matérn Fields

This work provides a class of non‐Gaussian spatial Matérn fields which are useful for analysing geostatistical data. The models are constructed as solutions to stochastic partial differential equations driven by generalized hyperbolic noise and are incorporated in a standard geostatistical setting with irregularly spaced observations, measurement errors and covariates. A maximum likelihood estimation technique based on the Monte Carlo expectation‐maximization algorithm is presented, and a Monte Carlo method for spatial prediction is derived. Finally, an application to precipitation data is presented, and the performance of the non‐Gaussian models is compared with standard Gaussian and transformed Gaussian models through cross‐validation.     

社会场域变迁背景下的失地农民城市融入问题研究——基于对昆明市Z社区的回迁调查

失地农民在城市化适应的过程中,并非简单地只是身份的转变,更意味着是一种生活方式和生活状态的彻底改变。失地农民在城市适应和融入的过程中暴露出来的问题主要是:经济收入的不确定、文化价值观的不一致和心理认同感不强以及内部之间存在各种利益博弈。从昆明市第一个回迁房小区Z社区的村民来看,失地农民要真正融入城市,是一种内在式的需求,即是否要变成城市人,关键是在农民自身内在需求的驱动下而决定的。他们根据自身的利益,在各个场域灵活变通地实践着各种惯习,在不断建构着自身的社会网络的同时也在不断建构着自身的社会资本。     

《了不起的盖茨比》的荒原色彩

《了不起的盖茨比》被誉为"散文版的《荒原》",菲茨杰拉德以丰富的色彩描写和精湛的象征为读者展示了荒原时代的美国社会:丰裕物质生活的背后是充满绝望和死亡的精神荒原。主要从语义场理论入手,探索色彩语义场与其象征寓意所构成的"荒原"。     

结合频域有限差分法分析二维柱体电磁散射

引入多波前算法,提出了结合频域有限差分法分析二维柱体的电磁散射问题。数值计算过程中利用Murs二阶吸收边界条件和场平均吸收条件截断网格;作为算例,分析了一无限长理想导体柱对平面电磁波的散射,由于使用了多波前算法求解差分矩阵方程,大大地减少了计算时间,数值结果表明了该方法的有效性。     

SLA研究的理论模式与研究领域

第二语言习得(SLA)研究作为一门独立的学科已经有了三十多年的历史,其间理论假设层出不穷,莫衷一是。本文梳理了五种有代表性的、对外语教学有指导意义的主要SLA理论,希望能对广大的外语教学工作者有教学参考价值。