This model implements the sensor characteristics described in [1]. It creates a sequence of random values with an interval of 15 minutes, smoothly interpolates the connecting lines between theses values, and superposes the true glucose concentration with the resulting sensor error.
[1] Breton, M.; Kovatchev, B.: Analysis, Modeling, and Simulation of the Accuracy of Continuous Glucose Sensors. Journal of Diabetes Science and Technology, Volume 2, Issue 5, 2008
This sensor model simply returns the unaltered glucose concentration in the interstitial fluid (if provided by the physiological model) or the blood.
This model implements the UVA/Padova model equations published by Dalla Man et al. in [1-4], but has been adapted such that the simulation output accurately matches that of the UVA/PADOVA Type 1 Diabetes Simulator (T1DMS) [5].
The following summary has been taken from [6]:
The following scheme visualizes the state variables (“compartments”) as circles and the interactions between them (important signals are depicted in rectangles):
It must be expressly pointed out that this is only a mathematical model which can at most describe the real processes in the human body approximately and in parts. Therefore, although the simulation results qualitatively resemble clinical curves, they must be interpreted with caution and are not suitable for deriving individual treatment strategies from them (see disclaimer). We do not assume any responsibility for the correctness of the results or damages of any kind resulting from the use of the simulator (see license).
[1] Dalla Man, Ch.; Camilleri, M.; Cobelli, C.: A System Model of Oral Glucose Absorption: Validation on Gold Standard Data. IEEE Transactions on Biomedical Engineering, Volume 53, Number 12, December 2006
[2] Dalla Man, Ch.; Raimondo, D.M.; Rizza, R. A.; Cobelli, C.: GIM, Simulation Software of Meal Glucose-Insulin Model. Journal of Diabetes Science and Technology, Volume 1, Issue 3, May 2007
[3] Dalla Man, C.; Rizza, R. A.; Cobelli, C.: Meal simulation model of the glucose-insulin system. IEEE Transactions on biomedical engineering, 54(10), 2007.
[4] Dalla Man, C.; Micheletto, F.; Lv, D.; Breton, M.; Kovatchev, B.; Cobelli, C.: The UVA/PADOVA Type 1 Diabetes Simulator: New Features. Journal of Diabetes Science and Technology, Volume 8, Issue 1, 2014.
[5] The University of Virginia. T1DMS (version 3.2) [Software]. 2008, 2014. Retrieved from https://tegvirginia.com/.
[6] Eichenlaub, M., Freckmann, G., Schrills, T., Reenberg, A.T., Ritschel, T., Jørgensen, J., Lüddeke, H.-J., Hohm, S., Seidler, I., Schmitzer, J., Betz, H., Blechschmidt, R.,
and Peuscher, H. (2023). A numerical comparison of the UVA/Padova type 1 diabetes simulator and the open-source simulator LT1. e-Poster at ATTD 2023.
The design of the block diagram was inspired by Clara Furió Novejarque et al. doi:10.1016/j.ifacol.2022.09.169.
More detail will be provided soon.
It must be expressly pointed out that this is only a mathematical model which can at most describe the real processes in the human body approximately and in parts. Therefore, although the simulation results qualitatively resemble clinical curves, they must be interpreted with caution and are not suitable for deriving individual treatment strategies from them (see disclaimer). We do not assume any responsibility for the correctness of the results or damages of any kind resulting from the use of the simulator (see license).
Breton, Marc D.: Physical activity – the major unaccounted impediment to closed loop control. Journal of Diabetes Science and Technology Volume 2 Issue 1, 2008.
This model is taken from the work of Hovorka et al [1], with implementation based on [2].
With the default parameters, this model has a very high insulin sensitivity and implies a very low basal rate.
In [1], the glucose absorption rate resulting from a meal was measured as a time signal
\[ U_G(t) = \dfrac{D_G\,A_G\,t\,e^{-t/t_{max,G}}}{t^2_{max,G}} \]This approach is only suitable for a single meal. It is more elegant to formulate glucose absorption as a solution of an initial value problem, as done in [2]. For this purpose, the original model must be extended by two compartments.
The following scheme visualizes the state variables included in the model and the interactions between them:
It must be expressly pointed out that this is only a mathematical model which can at most describe the real processes in the human body approximately and in parts. Therefore, although the simulation results qualitatively resemble clinical curves, they must be interpreted with caution and are not suitable for deriving individual treatment strategies from them (see disclaimer). We do not assume any responsibility for the correctness of the results or damages of any kind resulting from the use of the simulator (see license).
[1] Hovorka, R.; Canonico, V.; Chassin, L. J.; Haueter, U.; Massi-Benedetti, M.; Federici, M. O.; Pieber, T. R.; Schaller, H. C., Schaupp, L.; Vering, T.; Wilinska, M. E.: Nonlinear model predictive control of glucose concentration in subjects with type 1 diabetes. Journal of Phyiological Measurement, Volume 25, 2004.
[2] Andersen, S. H.: Software for in Silico Testing of an Artificial Pancreas. Master’s Thesis at Technical University of Denmark. 2014.
The arrangement of the block diagram was inspired by a template by Clara Furió Novejarque, Universitat Politècnica de València.
This is a simplified version of the UVA/Padova model as described by Dalla Man et al. in [3, 4]. It was used in the first version of LT1 due to difficulties with the implementation of parts of the model. The second version of LT1 contains a revised version of the UVA/Padova model.
The default values of the parameters are taken from the “Normal Value” column in [3, Table 1] and describe the behavior of a healthy person.
The following scheme visualizes the state variables included in the model and the interactions between them:
It must be expressly pointed out that this is only a mathematical model which can at most describe the real processes in the human body approximately and in parts. Therefore, although the simulation results qualitatively resemble clinical curves, they must be interpreted with caution and are not suitable for deriving individual treatment strategies from them (see disclaimer). We do not assume any responsibility for the correctness of the results or damages of any kind resulting from the use of the simulator (see license).
[1] Dalla Man, Ch.; Camilleri, M.; Cobelli, C.: A System Model of Oral Glucose Absorption: Validation on Gold Standard Data. IEEE Transactions on Biomedical Engineering, Volume 53, Number 12, December 2006
[2] Dalla Man, Ch.; Raimondo, D.M.; Rizza, R. A.; Cobelli, C.: GIM, Simulation Software of Meal Glucose-Insulin Model. Journal of Diabetes Science and Technology, Volume 1, Issue 3, May 2007
[3] Dalla Man, C.; Rizza, R. A.; Cobelli, C.: Meal simulation model of the glucose-insulin system. IEEE Transactions on biomedical engineering, 54(10), 2007.
[4] Dalla Man, C.; Micheletto, F.; Lv, D.; Breton, M.; Kovatchev, B.; Cobelli, C.: The UVA/PADOVA Type 1 Diabetes Simulator: New Features. Journal of Diabetes Science and Technology, Volume 8, Issue 1, 2014.
The design of the block diagram was inspired by Clara Furió Novejarque et al. doi:10.1016/j.ifacol.2022.09.169.
