Gray box modelling of arterial vasoaction

Abstract

Gray box modelling of physiological systems involves constructing a model structure based on physical knowledge of the system and model parameterisation using numerical techniques. This paper presents a gray box model of arterial vasoaction (the process of constricting and dilating blood vessels in order to maintain an appropriate level of blood pressure and blood flow). The model structure is built in accordance with the physical system. The initial parameterisation was manual, with the model consequently optimised using gradient techniques and genetic algorithms. The model was validated by demonstrating good correlation between experimental results and model output.

Nonlinear modelling of renal vasoaction

“…Once a model structure is defined, a number of numerical methods can be used for parameter optimisation. In [9] a number of optimisation techniques were compared to identify which optimisation method is mostly suited to the parameterisation of Model A described in the current paper.…”

“…While this linear model gives a good fit at relatively low SNA amplitudes, the response match deteriorates at higher SNA amplitudes, as this higher stimulation level evokes reactionary responses in (local) vasodilatory mechanisms. Previous work by our group [9,13] describe nonlinear mathematical models relating RBF to SNA. In [13] the model is only manually parameterised, while in [9] numerical optimisation was performed using various techniques and the resulting model fits were compared.…”

“…Previous work by our group [9,13] describe nonlinear mathematical models relating RBF to SNA. In [13] the model is only manually parameterised, while in [9] numerical optimisation was performed using various techniques and the resulting model fits were compared. Manual optimisation, gradient method (quasi-Newton algorithm), genetic algorithms (GAs) and a combination of GAs and the quasi-Newton algorithm were included in the comparison.…”