Abstract This work compares three well-known models and simulators in terms of their use in the analysis and design of glucose controllers for patients with Type 1 Diabetes Mellitus (T1DM). The ...objective is to compare them in practical scenarios which include: model uncertainty, time variance, nonlinearities, glucose measurement noise, delays between subcutaneous and plasma levels, pump saturation, and real-time controller implementation. The pros and cons of all models/simulators are presented. Finally, the simulators are tested with different robust controllers in order to identify the difficulties in the design and implementation phases. To this end, three sources of uncertainty are considered: nonlinearities, time-varying behavior (intra-patient) and inter-patient differences.
This paper aims to bridge the gap between neurophysiology and automatic control methodologies by redefining the Wilson-Cowan (WC) model as a control-oriented linear parameter-varying (LPV) system. A ...novel approach is presented that allows for the application of a control strategy to modulate and track neural activity.
The WC model is redefined as a control-oriented LPV system in this study. The LPV modelling framework is leveraged to design an LPV controller, which is used to regulate and manipulate neural dynamics.
Promising outcomes, in understanding and controlling neural processes through the synergistic combination of control-oriented modelling and estimation, are obtained in this study. An LPV controller demonstrates to be effective in regulating neural activity.
The presented methodology effectively induces neural patterns, taking into account optogenetic actuation. The combination of control strategies with neurophysiology provides valuable insights into neural dynamics. The proposed approach opens up new possibilities for using control techniques to study and influence brain functions, which can have key implications in neuroscience and medicine. By means of a model-based controller which accounts for non-linearities, noise and uncertainty, neural signals can be induced on brain structures.
•A personalized LPV model as a means to design adequate controllers for blood glucose regulation in type 1 diabetes is proposed.•The time-varying nature of the glucose-insulin dynamics is ...included.•Personalization to each patient is performed using the so-called 1800 rule.•Performance of the proposed control-oriented model is quantify in an open- and closed-loop fashion.
The contribution of this work is the generation of a control-oriented model for insulin-glucose dynamic regulation in type 1 diabetes mellitus (T1DM). The novelty of this model is that it includes the time-varying nature, and the inter-patient variability of the glucose-control problem. In addition, the model is well suited for well-known and standard controller synthesis procedures. The outcome is an average linear parameter-varying (LPV) model that captures the dynamics from the insulin delivery input to the glucose concentration output constructed based on the UVA/Padova metabolic simulator. Finally, a system-oriented reinterpretation of the classical ad-hoc 1800 rule is applied to adapt the model's gain.
The effectiveness of this approach is quantified both in open- and closed-loop. The first one by computing the root mean square error (RMSE) between the glucose deviation predicted by the proposed model and the UVA/Padova one. The second measure is determined by using the ν-gap as a metric to determine distance, in terms of closed-loop performance, between both models. For comparison purposes, both open- (RMSE) and closed-loop (ν-gap metric) quality indicators are also computed for other control-oriented models previously presented.
This model allows the design of LPV controllers in a straightforward way, considering its affine dependence on the time-varying parameter, which can be computed in real-time. Illustrative simulations are included. In addition, the presented modeling strategy was employed in the design of an artificial pancreas (AP) control law that successfully withstood rigorous testing using the UVA/Padova simulator, and that was subsequently deployed in a clinical trial campaign where five adults remained in closed-loop for 36h. This was the first ever fully closed-loop clinical AP trial in Argentina, and the modeling strategy presented here is considered instrumental in resulting in a very successful clinical outcome.
A new design methodology of gain scheduled controllers for wind turbines is presented. The proposed methodology is intended to deal with multi-variable and high order models as those produced by high ...fidelity aeroelastic simulators. The methodology consists in interpolating the local controller outputs and does not require a uniform state definition either of the local controllers or of the linear models. This allows the design of each controller independently, an essential point in cases of high order models. An aeroelastic model of a typical commercial wind turbine is used to illustrate the methodology.
► We propose a new design methodology of gain scheduled controllers for wind turbines. ► The proposed methodology is intended to deal with multi-variable and high order models. ► The methodology consists in interpolating the local controller outputs. ► The methodology does not require a uniform state definition of the local controllers ► Each local controller can be designed independently.
Selective media (potato dextrose agar plus yeast extract, different concentrations of cetyltrimethylammonium bromide (CTAB) and different antibacterials) were evaluated for the isolation of ...endophytic Beauveria cf. bassiana from dry bean (Phaseolus vulgaris) plants. CTAB amounts of 0.15 and 0.3 g/L plus either dihydrostreptomycin, oxytetracycline or doxycycline resulted in the lowest numbers of common saprophytic fungi and the highest proportional recovery of Beauveria colonies from internal plant tissues.
In a survey of natural enemies of the Asian citrus psyllid, Diaphorina citri, live adults of this insect were collected at and near the municipalities of Papantla and Tlapacoyan, in central Veracruz ...state, Mexico, and held in the laboratory looking for individuals infected with entomopathogenic fungi. A species of the fungus Entomophthora Cohn sensu stricto (Entomophthoromycota: Entomophthorales) was observed infecting 1.4% adult insects (n = 210) collected from orange Jessamine, Murraya paniculata, at the town of Venustiano Carranza, municipality of Papantla. Diaphorina citri is a new host record for this entomopathogenic fungal genus.
This paper presents an implementation of the unfalsified control (UC) method using the Riccati-based parameterisation of
controllers. The method provides an infinite controller set to (un)falsify the ...real-time data streams seeking for the best performance. Different sets may be designed to increase the degrees of freedom of the set of controller candidates to perform UC. In general, a set of m central controllers could be designed, each one seeking different objectives and all with their own parameterisation as a function of a stable and bounded transfer matrix. For example, one controller parameterisation could be designed to solve the robust stability of a model set which covers the physical system, therefore guaranteeing feasibility. The implementation requires the online optimisation of either quadratic fractional or quadratic problems, depending on the selection of the cost function. A multi-input, multi-output (MIMO) time-varying model of a permanent magnet synchronous generator illustrates the use of this technique.
Switched LPV Glucose Control in Type 1 Diabetes Colmegna, Patricio H.; Sanchez-Pena, Ricardo S.; Gondhalekar, Ravi ...
IEEE transactions on biomedical engineering,
06/2016, Letnik:
63, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Objective: The purpose of this paper is to regulate the blood glucose level in Type 1 Diabetes Mellitus patients with a practical and flexible procedure that can switch among a finite number of ...distinct controllers, depending on the user's choice. Methods: A switched linear parameter-varying controller with multiple switching regions, related to hypo-, hyper-, and euglycemia situations, is designed. The key feature is to arrange the controller into a framework that provides stability and performance guaranty. Results: The closed-loop performance is tested on the complete in silico adult cohort of the UVA/Padova metabolic simulator, which has been accepted by the U.S. Food and Drug Administration in lieu of animal trials. The outcome produces comparable or improved results with respect to previous works. Conclusion: The strategy is practical because it is based on a model tuned only with a priori patient information in order to cover the interpatient uncertainty. Results confirm that this control structure yields tangible improvements in minimizing risks of hyper- and hypoglycemia in scenarios with unannounced meals. Significance: This flexible procedure opens the possibility of taking into account, at the design stage, unannounced meals and/or patients' physical exercise.
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