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With the surge of short-range wireless applications, more networks are being deployed in the unlicensed radio band. The challenge that emerges is to accommodate these networks without breaching current rules and regulations on frequency usage. This paper studies the coexistence of several independent and dynamic wireless networks using the frequency hopping technique. We propose a novel hopping scheme that minimizes mutual interference and allows more networks to collocate effectively, but does not violate restrictions imposed by the Federal Communications Commission (FCC) regarding frequency constraint (related to the minimum number of frequencies in a hopping set) and time constraint (related to the maximum duration of using a particular frequency). The coexisting networks follow the Gaussian distribution in choosing transmission frequencies from parallel hopping spaces without the overhead of extra message exchange among networks. Simulation results on key metrics such as channel collision rate, goodput, and fairness in channel usage are presented to establish the viability of the proposed scheme in comparison with other contemporary approaches. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objective: To determine whether an intervention at both the provider and patient level can increase the utilization of diabetic retinal examination among diabetic patients and to compare the results from a comparable study conducted on the East Coast., Research Design and Methods: For the regional intervention study, all diabetic patients 18 years or older who enrolled in a large network-based health maintenance organization (HMO) in California were identified (n = 19,397). The identified diabetic patients received educational materials and a notification of their prior diabetic retinal examination status. Also, their primary care physicians received the current American Diabetes Association (ADA) guidelines for dilated retinal examinations and a list of patients due for diabetic retinal examination., Results: There were 25 and 27% increases in the percentage of diabetic patients who received diabetic retinal examinations in 1995 compared with the percentages in 1993 and 1994, respectively. The increase in diabetic retinal examinations was most significant after the intervention (odds ratio = 1.4). Furthermore, the improvements in compliance after the intervention were almost identical between the studies implemented on the East and West Coasts., Conclusions: This study and the prior study demonstrate that such a "reminder" intervention can improve compliance with diabetic retinal screening recommendations. A generalizable intervention, such as this, may be applicable on a national level. For these programs to be successful, however, HMOs and physicians must have a collaborative relationship.