Diabetes mellitus is characterized by insufficiency of the pancreas to produce enough insulin to regulate the blood sugar level. In type I diabetes, the pancreas produces no insulin, and the patient is totally dependent on insulin from an external source to be infused at a rate to maintain blood sugar levels at normal levels. Hyperglycemia occurs when blood glucose level rises much higher than the norm (>8 mmol/L) for prolonged periods of time; hypoglycemia occurs when the blood sugar level falls below values of 3 mmol/L. Both situations can be deleterious to the individual’s health. The normal range of blood sugar is between 3.8 and 5.6 mmol/L, the target range for a controller regulating blood sugar. A patient with type I diabetes needs your help to maintain her blood sugar within an acceptable range (3 mmol/L < glucose < 8 mmol/L). She has just eaten a large meal  (a disturbance) that you estimate will release glucose according to D(t) = 0.5e^-0.05t, where t is in minutes and D(t) is in mmol/L – min. She has a subcutaneous insulin pump that can release insulin up to 115 mU/min (mU = 10^-3 Unit of Insulin). The flow rate of insulin is the manipulated variable. Assume that the blood glucose level can be measured by taking blood insulin samples infrequently. Discuss control strategies from Chapters 15 and 16 that may be useful for solving this problem. Explain why a given strategy might be appropriate but also indicate possible pitfalls. Chapter 23 discusses a diabetes simulation.