A dual mode adaptive basal-bolus advisor based on reinforcement learning

Self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) are commonly used by type 1 diabetes (T1D) patients to measure glucose concentrations. The proposed adaptive basal-bolus algorithm (ABBA) supports inputs from either SMBG or CGM devices to provide personalised suggestions for the daily basal rate and prandial insulin doses on the basis of the patients' glucose level on the previous day. The ABBA is based on reinforcement learning (RL), a type of artificial intelligence, and was validated in silico with an FDA-accepted population of 100 adults under different realistic scenarios lasting three simulated months. The scenarios involve three main meals and one bedtime snack per day, along with different variabilities and uncertainties for insulin sensitivity, mealtime, carbohydrate amount, and glucose measurement time. The results indicate that the proposed approach achieves comparable performance with CGM or SMBG as input signals, without influencing the total daily insulin dose. The results are a promising indication that AI algorithmic approaches can provide personalised adaptive insulin optimisation and achieve glucose control - independently of the type of glucose monitoring technology.Comment: 9 pages, 8 figures, accepted by Journal of Biomedical and Health Informatics in December 201

The INCA System: A Further Step Towards a Telemedical Artificial Pancreas

Biomedical engineering research efforts have accomplished another level of a ldquotechnological solutionrdquo for diabetes: an artificial pancreas to be used by patients and supervised by healthcare professionals at any time and place. Reliability of continuous glucose monitoring, availability of real-time programmable insulin pumps, and validation of safe and efficient control algorithms are critical components for achieving that goal. Nevertheless, the development and integration of these new technologies within a telemedicine system can be the basis of a future artificial pancreas. This paper introduces the concept, design, and evaluation of the ldquointelligent control assistant for diabetes, INCArdquo system. INCA is a personal digital assistant (PDA)-based personal smart assistant to provide patients with closed-loop control strategies (personal and remote loop), based on a real-time continuous glucose sensor (Guardian RT, Medtronic), an insulin pump (D-TRON, Disetronic Medical Systems), and a mobile general packet radio service (GPRS)-based telemedicine communication system. Patient therapeutic decision making is supervised by doctors through a multiaccess telemedicine central server that provides to diabetics and doctors a Web-based access to continuous glucose monitoring and insulin infusion data. The INCA system has been technically and clinically evaluated in two randomized and crossover clinical trials showing an improvement on glycaemic control of diabetic patients

A new run-to-run approach for reducing contact bounce in electromagnetic switches

Contact bounce is probably the most undesirable phenomenon of electromagnetic switches. It reduces the performance of relays and contactors and is directly related to some of the processes that result in the destruction of the device. In this paper, a complete formulation of the problem is provided and a new strategy inspired by Runto-Run control is presented for reducing contact bounce. The method, which makes use of the repetitive functioning of these systems, is highly versatile and may be applied to different switches under diverse operating conditions. In addition, it is able to deal with changes during the service life of the device, such as plastic deformations or the erosion of the contacts. Several experimental results are included to prove the effectiveness of the method

A Survey of Insulin-Dependent Diabetes—Part II: Control Methods

We survey blood glucose control schemes for insulin-dependent diabetes therapies and systems. These schemes largely rely on mathematical models of the insulin-glucose relations, and these models are typically derived in an empirical or fundamental way. In an empirical way, the experimental insulin inputs and resulting blood-glucose outputs are used to generate a mathematical model, which includes a couple of equations approximating a very complex system. On the other hand, the insulin-glucose relation is also explained from the well-known facts of other biological mechanisms. Since these mechanisms are more or less related with each other, a mathematical model of the insulin-glucose system can be derived from these surrounding relations. This kind of method of the mathematical model derivation is called a fundamental method. Along with several mathematical models, researchers develop autonomous systems whether they involve medical devices or not to compensate metabolic disorders and these autonomous systems employ their own control methods. Basically, in insulin-dependent diabetes therapies, control methods are classified into three categories: open-loop, closed-loop, and partially closed-loop controls. The main difference among these methods is how much the systems are open to the outside people

A Globally Convergent Algorithm for the Run-to-Run Control of Systems with Sector Nonlinearities

Run-to-run control is a technique that exploits the repetitive nature of processes to iteratively adjust the inputs and drive the run-end outputs to their reference values. It can be used to control both static and finite-time dynamic systems. Although the run-end outputs of dynamic systems result from the integration of process dynamics during the run, the relationship between the input parameters p (fixed at the beginning of the run) and the run-end outputs z (available at the end of the run) can be seen as the static map z(p). Run-to-run control consists in computing the input parameters p∗ that lead to the reference values z_ref. Although a wide range of techniques have been reported, most of them do not guarantee global convergence, that is, convergence towards p∗ for all possible initial conditions. This paper presents a new algorithm that guarantees global convergence for the run-to-run control of both static and finite-time dynamic systems. Attention is restricted to sector nonlinearities, for which it is shown that a fixed gain update can lead to global convergence. Furthermore, since convergence can be very slow, it is proposed to take advantage of the mathematical similarity between run-to-run control and the solution of nonlinear equations, and combine the fixed-gain algorithm with a faster variable-gain Newton-type algorithm. Global convergence of this hybrid scheme is proven. The potential of this algorithm in the context of run-to-run optimization of dynamic systems is illustrated via the simulation of an industrial batch polymerization reactor

Multiple disturbance modeling and prediction of blood glucose in Type 1 Diabetes Mellitus

Type 1 diabetics often experience extreme variations in glucose concentrations which can have adverse long– and short–term effects such as severe hypoglycemia, hyperglycemia and organ degeneration. Studies have established that there is a need to maintain the glucose levels within a normal range (e.g. 80—150 mg/dL) to avoid complications caused by diabetes. However, initial attempts to regulate blood glucose levels using insulin infusion pumps, multiple injections or a combination of the two have had limited success as they lack the ability to decide the appropriate rate and/or dose of insulin based on the current metabolic state of the body. Consequently, what is needed is an automatic insulin delivery system (i.e., artificial pancreas) with the ability to determine continuously the rate of insulin delivery required to provide optimum closed-loop glucose control (i.e., to minimize the variability around a desired glucose level) and to eliminate the individual from the insulin dosage decision making in this control loop. Due to recent advances in biomedical technology, such as automatic insulin delivery systems using glucose sensors and insulin pumps, blood glucose modeling and control has received considerable attention in the process control community and models of various degrees of complexity have been developed. Glucose levels are affected by many variables, such as stress, physical activity, hormonal changes, periods of growth, medications, illness/infection, fatigue, as well as food intake and insulin tolerance. Furthermore, not only does glucose change from several sources of disturbances but their impact on blood glucose level is highly correlated, dynamic and nonlinear making it difficult to distinguish the effect each input has on blood glucose. Thus, the objective of this research is to introduce a modeling methodology that is able to take into account the simultaneous and multiple effects of food, activity, stress and their interactions. The research presented in this thesis is carried out on 15 Type 1 diabetic subjects where thirteen variables (i.e., three food variables, seven activity variables, basal insulin, bolus insulin, and time of day (TOD)) are collected for two weeks and modeled using the Wiener block–oriented model. Three types of models are compared: input–only (Model 1), input–output (Model 2), and output–only (Model 3). Results are given for k –steps ahead prediction (k –SAP) from 5 minutes to 3 hours in the future and show the importance of taking into account the interactions between input variables