Patrick Mair

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This introduction to the R package isotone is a (slightly) modified version of de Leeuw et al. (2009), published in the Journal of Statistical Software. In this paper we give a general framework for isotone optimization. First we discuss a generalized version of the pool-adjacent-violators algorithm (PAVA) to minimize a separable convex function with simple(More)
Identifying the language used will typically be the first step in most natural language processing tasks. Among the wide variety of language identification methods discussed in the literature, the ones employing the Cavnar and Trenkle (1994) approach to text categorization based on character n-gram frequencies have been particularly successful. This paper(More)
In this article, we extend the discussion of prediction models of Configural Frequency Analysis (CFA). We build on the correspondence of such prediction models to logit models that was shown by von Eye and Bogat (in this issue), and derive additional possible CFA prediction models. These models can, as is illustrated, include multiple predictors and(More)
The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from a standing position and task specific spine ranges of motion objectively assess muscle function in healthy young and middle age individuals. However, literature on neuromuscular activation and associated spine and hip kinematics(More)
This article develops a procedure based on copulas to simulate multivariate nonnormal data that satisfy a prespecified variance-covariance matrix. The covariance matrix used can comply with a specific moment structure form (e.g., a factor analysis or a general structural equation model). Thus, the method is particularly useful for Monte Carlo evaluation of(More)