Practical Maximum Pseudolikelihood for Spatial Point Patterns(with Discussion)

This paper describes a technique for computing approximate maximum pseudolikelihood estimates of the parameters of a spatial point process. The method is an extension of Berman & Turner's (1992) device for maximizing the likelihoods of inhomogeneous spatial Poisson processes. For a very wide class of spatial point process models the likelihood is intractable, while the pseudolikelihood is known explicitly, except for the computation of an integral over the sampling region. Approximation of this integral by a finite sum in a special way yields an approximate pseudolikelihood which is formally equivalent to the (weighted) likelihood of a loglinear model with Poisson responses. This can be maximized using standard statistical software for generalized linear or additive models, provided the conditional intensity of the process takes an 'exponential family' form. Using this approach a wide variety of spatial point process models of Gibbs type can be fitted rapidly, incorporating spatial trends, interaction between points, dependence on spatial covariates, and mark information.     

Assessment of Uncertainty in High Frequency Data: The Observed Asymptotic Variance

The availability of high frequency financial data has generated a series of estimators based on intra‐day data, improving the quality of large areas of financial econometrics. However, estimating the standard error of these estimators is often challenging. The root of the problem is that traditionally, standard errors rely on estimating a theoretically derived asymptotic variance, and often this asymptotic variance involves substantially more complex quantities than the original parameter to be estimated. Standard errors are important: they are used to assess the precision of estimators in the form of confidence intervals, to create “feasible statistics” for testing, to build forecasting models based on, say, daily estimates, and also to optimize the tuning parameters. The contribution of this paper is to provide an alternative and general solution to this problem, which we call Observed Asymptotic Variance. It is a general nonparametric method for assessing asymptotic variance (AVAR). It provides consistent estimators of AVAR for a broad class of integrated parameters Θ = ∫ θ_t dt, where the spot parameter process θ can be a general semimartingale, with continuous and jump components. The observed AVAR is implemented with the help of a two‐scales method. Its construction works well in the presence of microstructure noise, and when the observation times are irregular or asynchronous in the multivariate case. The methodology is valid for a wide variety of estimators, including the standard ones for variance and covariance, and also for more complex estimators, such as, of leverage effects, high frequency betas, and semivariance.     

离子液体在萃取分析中的应用

室温离子液体被认为是一种多功能的新型绿色溶剂,其应用十分广泛。其特点是几乎没有蒸汽压、溶解度大、溶解范围广、易于回收利用、稳定性好。本文介绍了离子液体在萃取方面的应用,包括液?液萃取,固?固分离,液?固萃取,气体的吸收分离,与超临界CO2结合的萃取分离以及膜萃取等方面的应用研究进展情况。     

前沿意识、学术积累与学术创新 ——社科类学术论文写作应注意的几个问题

前沿意识是指研究者对所研究的学科、领域研究动态的把握;学术积累是指研究者为其研究所做的学术准备工作.学术创新是指研究者在其科研活动中所提出的新的观点、新的研究方法和新的研究思路.只有树立前沿意识,才能够避免科研工作的盲目性,选准研究的突破口;才能充分借鉴他人的研究成果,起到事半功倍的效果.只有重视学术积累,进行广泛而深厚的学术积累,才能超越前人,取得创新性成果.缺乏前沿意识,疏于学术积累,其结果只能对学术研究活动造成戕害.     

超临界流体萃取装置使用指南

超临界流体萃取(SFE)是近年来兴起的一种新的分离技术,本文简述了超临界萃取装置的工作原理及操作方法,并对研究人员如何正确使用超临界萃取装置提出了一些注意事项,希望对研究人员使用超临界萃取装置提供一些帮助。     

最优的核判别分析用于雷达目标识别

特征提取是雷达目标识别研究中的重要问题,有效、稳健的特征是提高识别率的关键。核判别分析(KDA)是一种抽取非线性特征的有效方法,但它会因为奇异性问题而难以求解。基于子空间投影的思想,给出一种最优的核判别分析(OKDA)方法,用于对雷达目标的距离像进行特征提取,然后采用基于核的非线性分类器对所提取的特征进行分类,实现对雷达目标的识别。分别对仿真和实测距离像进行实验,结果表明该方法具有较好的识别效果。     

核心价值：从“天上”到“人间”

任何社会都有其独特的精神气质，它植根于现实的生产方式、政治氛围和文化底蕴之中，普照了当下的道德、法律规范和人们的价值追求，建构了社会的核心价值及其体系。核心价值，从逻辑运思来看，它是中心和边缘的统一，代表着整个价值体系的总的特征和方向，决定和规制着非核心价值；它内在地蕴含着一种自为的实践的价值机理，这样的核心价值及其理论体系因此获得了旗帜性和范导性的生活表征。     

贵州矿产开采业产业链整合实证研究的调研报告

贵州省凭借拥有矿产资源储量优势，目前已将矿产开采业作为拉动贵州经济的支柱产业，但是，资源量大的同时，经济利用较差，绝大多数开采企业规模较小，能否利用资源优势，仍面临不少问题和挑战。本文是对贵州81家开采企业的调研报告，希望已此为基础，探讨如何将贵州资源优势转变为产业优势，以增强贵州矿产开采企业的竞争优势。     

用干涉滤波技术实现图象边缘增强

本文提出了用干涉及滤波技术实现图象边缘增强的一种新方法。将同一物体的一张正确对焦的透明片与另一张离焦的透明片重叠放在透镜的前面,在单色平行光照射下,在透镜的后焦面上得到两图象的谱的干涉,通过对干涉条纹的适当滤波,可在输出面得到边缘增强的象。     

苯等离子体降解中间产物的萃取与分离

应用接触辉光放电等离子体对苯水溶液进行了降解,对部分降解产物进行了萃取分离,并用高效液相色谱法对中间产物分进行了测定.在194nm下检测到了苯酚,苯醌,甲酸,草酸和丙二酸等中间产物.