A method for determining an insulin dosing recommendation comprising: taking a measurement of blood glucose concentration in a patient at each of a plurality of actuation times; applying an adaptive observer scheme at each actuation time to estimate a present physiological state of a patient based on the most recent measurement of blood glucose concentration in the patient, wherein the adaptive observer scheme models the present physiological state of the patient using a dynamic model, wherein the dynamic model is one of: a minimal model of glucose kinetics (MMGK), and wherein the MMGK is augmented to take into account transport of insulin from an injection site to central circulation, as well as transport of glucose from the patient's stomach to central circulation; a reduced meal model, and wherein the RMM is augmented using two subcutaneous insulin equations, an interstitial glucose equation, and modeling a meal via a single equation; an augmented meal model, which is augmented by two additional insulin states for transport and an additional interstitial glucose compartment; storing the estimate of the patient's present physiological state; and applying the estimated physiological state to a Linear Quadratic regulator to determine an insulin dosing recommendation based on the present physiological state so estimated, wherein the Linear Quadratic regulator uses Linear Quadratic methodology to determine an insulin dosing recommendation based on the estimate of the patient's present physiological state and based on any stored estimates of the patient's physiological state, and wherein the insulin dosing recommendation is defined as a linear combination of a gain vector and a state vector, so as to minimize a quadratic cost function. taking a measurement of blood glucose concentration in a patient at each of a plurality of actuation times; applying an adaptive observer scheme at each actuation time to estimate a present physiological state of a patient based on the most recent measurement of blood glucose concentration in the patient, wherein the adaptive observer scheme models the present physiological state of the patient using a dynamic model, wherein the dynamic model is one of: a minimal model of glucose kinetics (MMGK), and wherein the MMGK is augmented to take into account transport of insulin from an injection site to central circulation, as well as transport of glucose from the patient's stomach to central circulation; a reduced meal model, and wherein the RMM is augmented using two subcutaneous insulin equations, an interstitial glucose equation, and modeling a meal via a single equation; an augmented meal model, which is augmented by two additional insulin states for transport and an additional interstitial glucose compartment; a minimal model of glucose kinetics (MMGK), and wherein the MMGK is augmented to take into account transport of insulin from an injection site to central circulation, as well as transport of glucose from the patient's stomach to central circulation; a reduced meal model, and wherein the RMM is augmented using two subcutaneous insulin equations, an interstitial glucose equation, and modeling a meal via a single equation; an augmented meal model, which is augmented by two additional insulin states for transport and an additional interstitial glucose compartment; storing the estimate of the patient's present physiological state; and applying the estimated physiological state to a Linear Quadratic regulator to determine an insulin dosing recommendation based on the present physiological state so estimated, wherein the Linear Quadratic regulator uses Linear Quadratic methodology to determine an insulin dosing recommendation based on the estimate of the patient's present physiological state and based on any stored estimates of the patient's physiological state, and wherein the insulin dosing recommendation is defined as a linear combination of a gain vector and a state vector, so as to minimize a quadratic cost function.