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利用新条件距离法稳健估计林分密度AI 解读

Estimators for the density of points in a plane may be unbiased for the spatial pattern for which they were designed but are usually biased for most others. Two new estimators are proposed which are approximately unbiased for a wide range of patterns, and are used on data in the form of the positions of the centres of trees in a forest stand.

高斯格点过程空间相互作用的估计与检验AI 解读

Maximum likelihood estimation for rectangular lattice autonormal schemes is discussed. Explicit results for the first-order isotropic scheme are given and compared with those obtained using a simple coding technique. The efficiency of the coding technique in testing for randomness on various types of lattice is assessed.

利用距离方法进行稳健密度估计AI 解读

Distance estimators of density may exhibit serious bias unless the population under consideration forms a completely random spatial pattern, i.e. the estimators are not robust. In this paper some new estimators are proposed, and their robustness is assessed analytically against two stochastic models, which together embrace a continuous range of spatial pattern, from extreme regularity, through randomness, to extreme aggregation.

空间相互作用模型的估计方法AI 解读

Autoregressive models for spatial interaction have been proposed by several authors (Whittle [15] and Mead [11], for example). In the past, computational difficulties with the ML approach have led to the use of alternative estimators. In this article, a simplified computational scheme is given and extended to mixed regressive-autoregressive models. The ML estimator is compared with several alternatives.

高斯格点过程空间交互的估计与检验AI 解读

Maximum likelihood estimation for rectangular lattice autonormal schemes is discussed. Explicit results for the first-order isotropic scheme are given and compared with those obtained using a simple coding technique. The efficiency of the coding technique in testing for randomness on various types of lattice is assessed.

基于距离方法的稳健空间密度估计AI 解读

Distance estimators of density may exhibit serious bias unless the population under consideration forms a completely random spatial pattern, i.e. the estimators are not robust. In this paper some new estimators are proposed, and their robustness is assessed analytically against two stochastic models, which together embrace a continuous range of spatial pattern, from extreme regularity, through randomness, to extreme aggregation.

摘要暂缺

空间相互作用与格点系统的统计分析AI 解读

Summary The formulation of conditional probability models for finite systems of spatially interacting random variables is examined. A simple alternative proof of the Hammersley–Clifford theorem is presented and the theorem is then used to construct specific spatial schemes on and off the lattice. Particular emphasis is placed upon practical applications of the models in plant ecology when the variates are binary or Gaussian. Some aspects of infinite lattice Gaussian…

空间冲突的随机模型AI 解读

SUMMARY Two species compete for territory along their mutual boundary. The species are fairly matched and the result of conflict is the invasion by one of the species of territory held by the other. A simple stochastic model for this process is described and rules are given for the calculation, as a function of time, of the probabilities that individual territories and groups of territories are held by a single species. Asymptotic results are given for the pattern of…

地形相关、幂律协方差函数与扩散AI 解读

Evidence from agricultural uniformity trials strongly indicates that the covariance function of yield in the plane, Γ(s), decays ultimately as s −1 , the inverse of distance (see §2 and the figure). A diffusion model (1) is examined in a varying number of spatial dimensions: in three dimensions it proves to generate an s −1 covariance law, (6). In §4 modifications of the model are examined which have the effect of removing singularities of Γ(s) at s = 0. In §5 I consider the…

交易流总体分析的统计模型AI 解读

This is applicable to the flow of any kind of quantifiable transactions, and to matrices from three to more than one hundred actors, utilizing a 650 IBM electronic computer or similar equipment. The method develops a matrix of expected or baseline data from assumptions of complete indifference among the actors, and measures the plus or minus differences between this baseline value and the actual amount of transactions in each direction for every pair of actors. It thus…

机器服务干扰的若干问题AI 解读

SUMMARY The problem of interference arises when a team of operatives is attending a set of machines, these being assumed to have a certain servicing factor. In this paper an estimator of the servicing factor and a simple expression for the machine efficiency are introduced. A loss function is also given, with a method for the determination of an appropriate number of operatives to be applied for the attendance of the machines.

多名维修人员条件下机器干扰问题的正态近似AI 解读

Summary An approximate solution of the machine interference problem with many repairmen is derived in terms of the normal distribution.

邮寄问卷的抽样程序AI 解读

T HE mailed questionnaire is desirable in surveys because it is economical of money and effort, free from the interviewer's effect on the respondent, and able to reach individuals not accessible by visit or telephone. However, it has several drawbacks which can seriously limit its efficiency as a means of gathering reliable data. The mailed answers are often exposed to two kinds of bias: (1) bias arising from the respondents' misunderstanding the questions, resentment of…

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摘要暂缺

随机原因的叠加作为周期过程的来源AI 解读

ALMOST ALL of the phenomena of economic life, like many other processes, social, meteorological, and others, occur in sequences of rising and falling movements, like waves. Just as waves following each other on the sea do not repeat each other perfectly, so economic cycles never repeat earlier ones exactly either in duration or in amplitude. Nevertheless, in both cases, it is almost always possible to detect, even in the multitude of individual peculiarities of the…