Donald R. Johnson

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In variational data assimilation, optimal ingestion of the observational data and optimal use of prior physical and statistical information involve the choice of numerous weighting, smoothing and tuning parameters which control the ltering and merging of divers sources of information. Generally these weights must be obtained from a partial and imperfect(More)
Dedicated to the memory of Henry Fleming and his contributions to Meteorology and Mathematics. Abstract We consider the problem of ingesting scattered, noisy, heterogeneous data into an imperfect, evolving mathematical model for the purpose of prediction of a dynamical system. In particular we consider models which perform a three or four dimensional data(More)
A method is described for recording and analysing the projected shape of mouse vertebrae. The image of the shape is captured by a television camera, cleaned, digitized and subjected to mathematical analysis. A visual representation is obtained by reconstructing the shape in polar coordinates about its centre of area. Further statistical analysis of the(More)
The race and sex of the human skull can be determined by craniometry. In this paper we suggest that a large number of craniometric measurements does not necessarily give the best possible discrimination for race and test the performance of subsets of variables drawn from various skull regions, or extracted mathematically on the basis of their discriminatory(More)
In Wahba et al. it was shown how the randomized trace method could be used to adaptively tune numerical weather prediction models via generalized cross validation (GCV) and related methods. In this paper a ''toy'' four-dimensional data assimilation model is developed (actually one space and one time variable), consisting of an equivalent barotropic(More)
A new method, smoothing spline ANOVA, for combining station records of surface air temperature to get the estimates of regional averages as well as gridpoint values is proposed. This method is closely related to the optimal interpolation (also optimal averaging) method. It may be viewed as a generalization of these methods from spatial interpolation methods(More)
OBJECT This study was conducted to compare the quality of life (QOL) in patients with neurogenic intermittent claudication (NIC) secondary to lumbar spinal stenosis (LSS). Using the 36-Item Short Form (SF-36) questionnaire, the authors compared the results obtained in patients treated with the X STOP Interspinous Process Decompression (IPD) System with(More)
Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These(More)
The pattern of variation of certain vertebral measurements along the vertebral column is known to differ in man and mouse. This paper investigates changes in this pattern in 7 species of small mammals and attempts to correlate them with locomotor adaptations and limb dimensions.
In this paper we examine metamerism in the vertebral column of certain mammals from the perspectives of development and adaptation. To this end we examine the patterns of metameric variation of dimensions of the neural (vertebral) canal, vertebral body and spinous process in man and inbred strains of mice. The data from inbred strains of mice indicate that(More)