• Opportunistic spectrum access (OSA) in cognitive radio networks: using efficiently the radio frequency spectrum • Traditional static spectrum allocation to licensed primary users (PUs): severe inefficiencies, measurements indicate low spectrum utilization (under 30 %) • Dramatic demand surge for spectrum access by unlicensed secondary users (SUs), due to emerging technologies • OSA: dynamical...

Based on the non-cooperative power control game theory, we propose an efficient and unbiased power control algorithm in cognitive radio network (CRN) by improving the utility function. Without causing interference to the primary users (PUs), this effective utility function balances the fairness and system throughput of secondary users (SUs) via a fair pricing function. The pricing punishment pa...

HYPOTHESIS Surgeon-performed ultrasound (SUS) and fine-needle aspiration (FNA) may guide the management of dominant thyroid nodules of the isthmus. DESIGN Retrospective review of prospectively collected data. SETTING Tertiary academic referral center. PATIENTS Of 942 patients who underwent preoperative SUS and FNA, followed by thyroidectomy, between January 1, 2002, and April 10, 2010, a ...

BACKGROUND To elucidate further from the biomechanical aspect whether microgravity-induced cerebral vascular mal-adaptation might be a contributing factor to postflight orthostatic intolerance and the underlying mechanism accounting for the potential effectiveness of intermittent artificial gravity (IAG) in preventing this adverse effect. METHODOLOGY/PRINCIPAL FINDINGS Middle cerebral arterie...

Members of the family Suidae have diverged over extended evolutionary periods in diverse environments, suggesting that adaptation in response to endemic infectious agents may have occurred. Toll-like receptors (TLRs) comprise a multigene family that acts as the first line of defense against infectious microbes at the host-environment interface. We hypothesized that across the Suidae, positive s...

BACKGROUND Health care spending is concentrated among a small number of high-cost patients, and the popularity of initiatives to improve care and reduce cost among such "superusers" (SUs) is growing. However, SU costs decline naturally over time, even without intervention, a statistical phenomenon known as regression-to-the-mean (RTM). OBJECTIVES We assess the magnitude of RTM in hospital cos...

In a cognitive radio network, a primary user (PU) shares its spectrum with secondary users (SUs) temporally and spatially, while allowing for some interference. Consider the problem of estimating the no-talk region of the PU, i.e., the region outside which SUs may utilize the PU’s spectrum regardless of whether the PU is transmitting or not. And propose a adaptive boundary estimation algorithm ...

In many natural situations, one observes a local system with many competing species that is coupled by weak immigration to a regional species pool. The dynamics of such a system is dominated by its stable and uninvadable (SU) states. When the competition matrix is random, the number of SUs depends on the average value and variance of its entries. Here we consider the problem in the limit of wea...