A glucose level control system, comprising: a glucose sensor operative to continually measure a glucose level of a subject and generate a corresponding glucose level signal; an insulin delivery device operative in response to an insulin dose control signal to infuse insulin into the subject; and a controller having online operation to generate the insulin dose control signal to achieve and maintain euglycemia in the subject, online operation employing a control algorithm including (i) regular administration of correction doses of insulin based on control parameters of the control algorithm and regular periodic sampling of glucose levels via the glucose sensor, and (ii) autonomously adjusting the control parameters to tailor the control parameters to the subject, characterized by the controller having offline operation to generate the insulin dose control signal to achieve and maintain euglycemia in the subject, offline operation including (iii) evolving a state of the control algorithm over time without sampling of glucose levels and without automatic administration of the correction doses of insulin, the state of the control algorithm being evolved during the offline operation by updating time effects of insulin previously administered to the subject to model a diminishing of an on-board insulin level in the subject during the offline operation, and (iv) correction dosing operations each including user-controlled administration of a correction dose of insulin in response to an isolated glucose measurement provided to the controller, the correction dose being calculated by the controller based on the isolated glucose measurement, the control parameters, and the state of the control algorithm as evolved at the time of the correction dosing operation. a glucose sensor operative to continually measure a glucose level of a subject and generate a corresponding glucose level signal; an insulin delivery device operative in response to an insulin dose control signal to infuse insulin into the subject; and a controller having online operation to generate the insulin dose control signal to achieve and maintain euglycemia in the subject, online operation employing a control algorithm including (i) regular administration of correction doses of insulin based on control parameters of the control algorithm and regular periodic sampling of glucose levels via the glucose sensor, and (ii) autonomously adjusting the control parameters to tailor the control parameters to the subject, characterized by the controller having offline operation to generate the insulin dose control signal to achieve and maintain euglycemia in the subject, offline operation including (iii) evolving a state of the control algorithm over time without sampling of glucose levels and without automatic administration of the correction doses of insulin, the state of the control algorithm being evolved during the offline operation by updating time effects of insulin previously administered to the subject to model a diminishing of an on-board insulin level in the subject during the offline operation, and (iv) correction dosing operations each including user-controlled administration of a correction dose of insulin in response to an isolated glucose measurement provided to the controller, the correction dose being calculated by the controller based on the isolated glucose measurement, the control parameters, and the state of the control algorithm as evolved at the time of the correction dosing operation.