A multivariate solution for cyclic data, applied in modelling locomotor forces

1987 ◽  
Vol 56 (1) ◽  
pp. 1-9 ◽  
Author(s):  
W. G. S. Hines ◽  
R. J. O'Hara-Hines ◽  
J. D. Brooke
Keyword(s):  
Cyclic Data

Importance of oscillations in alveolar gas concentrations in the analysis of rebreathing data

1986 ◽  
Vol 61 (3) ◽  
pp. 1104-1113 ◽  
Author(s):  
K. H. Weisiger ◽  
G. D. Swanson
Keyword(s):  
Time Course ◽  
Continuous Process ◽  
Inert Gases ◽  
Accurate Estimation ◽  
Gas Solubility ◽  
Estimation Errors ◽  
Gas Uptake ◽  
Cyclic Model ◽  
Low Solubility ◽  
Cyclic Data

Cyclic rebreathing of a soluble inert gas can be used to estimate lung tissue volume (Vt) and pulmonary blood flow (Qc). A recently proposed method for analyzing such cyclic data (Respir. Physiol. 48: 255–279, 1982) mathematically assumes that ventilation is a continuous process. However, neglecting the cyclic nature of ventilation may prevent the accurate estimation of Vt and Qc. We evaluated this possibility by simulating the uptake of soluble inert gases during rebreathing using a cyclic model of gas exchange. Under cyclic uptake conditions alveolar gases follow an oscillating time course, because gas concentrations tend to increase during inspiration and to decrease during expiration. We found that neglecting these alveolar gas oscillations leads to the underestimation of soluble gas uptake by blood, particularly during the early rebreathing breaths. When continuous ventilation is assumed Vt and Qc are overestimated unless rapid rebreathing rates, large tidal volumes, and gases of moderately low solubility are used. Under these conditions the amplitude of the cyclic oscillations is minimized, the alveolar time course more closely resembles that expected from continuous ventilation, and the resulting errors are minimized. Alternatively, when the effect of oscillating alveolar gas concentrations on mass transfer are considered, these estimation errors can be eliminated without restricting rebreathing rate or gas solubility. We conclude that failure to consider the effect of cyclic rebreathing on the time course of alveolar gas concentrations may result in significant errors when evaluating rebreathing data for Vt and Qc.

Cyclic Data Control Charts

1979 ◽  
Vol 11 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Eric E. Johnson ◽  
Richard W. Counts
Keyword(s):  
Control Charts ◽  
Data Control ◽  
Cyclic Data

scholarly journals Design and Implementation of the ScaLAPACK LU, QR, and Cholesky Factorization Routines

1996 ◽  
Vol 5 (3) ◽  
pp. 173-184 ◽  
Author(s):  
Jaeyoung Choi ◽  
Jack J. Dongarra ◽  
L. Susan Ostrouchov ◽  
Antoine P. Petitet ◽  
David W. Walker ◽  
...  
Keyword(s):  
Message Passing ◽  
Linear Equations ◽  
Building Blocks ◽  
Significant Loss ◽  
Cholesky Factorization ◽  
System Of Linear Equations ◽  
Major Objective ◽  
Dense System ◽  
Intel Paragon ◽  
Cyclic Data

This article discusses the core factorization routines included in the ScaLAPACK library. These routines allow the factorization and solution of a dense system of linear equations via LU, QR, and Cholesky. They are implemented using a block cyclic data distribution, and are built using de facto standard kernels for matrix and vector operations (BLAS and its parallel counterpart PBLAS) and message passing communication (BLACS). In implementing the ScaLAPACK routines, a major objective was to parallelize the corresponding sequential LAPACK using the BLAS, BLACS, and PBLAS as building blocks, leading to straightforward parallel implementations without a significant loss in performance. We present the details of the implementation of the ScaLAPACK factorization routines, as well as performance and scalability results on the Intel iPSC/860, Intel Touchstone Delta, and Intel Paragon System.

Sign in / Sign up

Export Citation Format

Share Document