Fraser Cameron

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BACKGROUND Control algorithms that regulate blood glucose (BG) levels in individuals with type 1 diabetes mellitus face several fundamental challenges. Two of these are the asymmetric risk of clinical complications associated with low and high glucose levels and the irreversibility of insulin action when using only insulin. Both of these nonlinearities(More)
Type-II Hybrid-ARQ (Type-II HARQ) has been shown, under certain circumstances, to increase the efficiency and reduce packet loss of data transmissions over a wireless channel. We present a model for evaluating the performance of packet transmissions over a wireless link employing Type-II HARQ error mitigation. Considering a channel subject to correlated bit(More)
OBJECTIVE Nocturnal hypoglycemia can cause seizures and is a major impediment to tight glycemic control, especially in young children with type 1 diabetes. We conducted an in-home randomized trial to assess the efficacy and safety of a continuous glucose monitor-based overnight predictive low-glucose suspend (PLGS) system. RESEARCH DESIGN AND METHODS In(More)
OBJECTIVE The purpose of this study was to develop an advanced algorithm that detects pending hypoglycemia and then suspends basal insulin delivery. This approach can provide a solution to the problem of nocturnal hypoglycemia, a major concern of patients with diabetes. RESEARCH DESIGN AND METHODS This real-time hypoglycemia prediction algorithm (HPA)(More)
BACKGROUND Nocturnal hypoglycemia is a significant problem. From 50% to 75% of hypoglycemia seizures occur at night. Despite the development of real-time glucose sensors (real-time continuous glucose monitor [CGM]) with hypoglycemic alarms, many patients sleep through these alarms. The goal of this pilot study was to assess the feasibility using a real-time(More)
BACKGROUND An insulin pump shutoff system can prevent nocturnal hypoglycemia and is a first step on the pathway toward a closed-loop artificial pancreas. In previous pump shutoff studies using a voting algorithm and a 1 min continuous glucose monitor (CGM), 80% of induced hypoglycemic events were prevented. METHODS The pump shutoff algorithm used in(More)
Type-II Hybrid-ARQ (Type-II HARQ) has been shown, under certain circumstances, to increase the efficiency and reduce loss of data transmissions over a wireless channel. However, it is difficult to predict how it will perform when transmission symbol errors are correlated. We present a computationally efficient approach to the performance evaluation of(More)
Aerobic exercise can lower blood glucose levels and alter insulin sensitivity both during and several hours after exercise, creating challenges for a closed-loop artificial pancreas. Predictive low glucose suspend (PLGS) algorithms are a first step toward an artificial pancreas, but few of these have been successfully applied to exercise. This study(More)
OBJECTIVE The aim of this study was to develop a partial closed-loop system to safely prevent nocturnal hypoglycemia by suspending insulin delivery when hypoglycemia is predicted in type 1 diabetes. RESEARCH DESIGN AND METHODS Forty subjects with type 1 diabetes (age range 12-39 years) were studied overnight in the hospital. For the first 14 subjects,(More)