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Functional data analysis techniques provide an alternative way of representing movement and movement variability as a function of time. In particular, the registration of functional data provides a local normalization of time functions. This normalization transforms a set of curves, records of repeated trials, yielding a new set of curves that only vary in(More)
This paper presents an application of functional principal component analysis (FPCA) to describe the inter-subject variability of multiple waveforms. This technique was applied to the study of sit-to-stand movement in two groups of people, osteoarthritic patients and healthy subjects. Although STS movement has not been extensively applied to the study of(More)
This paper presents a new, simple model to evaluate the instrumental random errors in kinematic analysis of human movements using stereophotogrammetry. By means of equations analogous to that relate linear or angular momentum with linear or angular velocities, a direct measurement of instantaneous motion can be made without previous finite displacement(More)
In this paper we propose a simple model to predict the effect of linear time normalization to reduce variability in human movement analysis. This model is based on analysis of the correlation between timing variables and total movement duration. We obtain a simple expression to predict the variation coefficient (CV) of the normalized variable as a function(More)
This paper proposes a kinematic approach for describing soft tissue artifacts (STA) in human movement analysis. Artifacts are represented as the field of relative displacements of markers with respect to the bone. This field has two components: deformation component (symmetric field) and rigid motion (skew-symmetric field). Only the skew-symmetric component(More)
A method for deriving attenuation time-series on fixed satellite or terrestrial links is described. The method uses meteorological forecast and radar data and permits time coincident derivations for multiple sites that include the inherent spatial correlation properties. The paper describes the approach adopted in the technique and presents preliminary(More)
  • Alvaro Page
  • 1987
This paper gives a program in BASIC for calculating the kinetic parameters Km and Vmax for an enzyme reaction from a set of paired values of reaction velocity at given substrate concentrations. An initial estimate of the two parameters is made using a weighted linear regression, these values are then used in an iterative process to fit the data to the(More)