Impact of the number of users on error probabilities in multiuser diversity systems

Multiuser diversity gain has been investigated well in terms of a system capacity formulation in the literature. In practice, however, designs on multiuser systems with nonzero error rates require a relationship between the error rates and the number of users within a cell. Considering a best-user scheduling, where the user with the best channel condition is scheduled to transmit per scheduling interval, our focus is on the uplink. We assume that each user communicates with the base station through a single-input multiple-output channel. We derive a closed-form expression for the average BER, and analyze how the average BER goes to zero asymptotically as the number of users increases for a given SNR. Note that the analysis of average BER even in SI SO multiuser diversity systems has not been done with respect to the number of users for a given SNR. Our analysis can be applied to multiuser diversity systems with any number of antennas.

Layered RF Phantom Characterization for Wireless Medical Vital Sign Monitors

Wearable antenna performance measurements were used to characterize a synthetic variable layered phantom testbed, representative of human tissue for operation in the 868/915 MHz, and 2400 MHz industrial, scientific and medical frequency bands. Antenna radiation efficiency measurements on the phantom were compared with measurements on the thorax region of a human test subject. The results show that the phantom is representative of the human body for the application of wireless vital sign monitors, where conductive connections are made to the tissue.

Evaluation of the contribution of theatre attendance to medical undergraduate neuroscience teaching - a pilot study.

Introduction: Medical students often attend the neurosurgical theatre during their clinical neurosciences attachment. However, few studies have been performed to objectively assess the value of this theatre-based learning experience. The main aim of this study was to explore student perceptions on the contribution of neurosurgical theatre attendance to clinical neuroscience teaching.

Materials and Methods: Third-year medical students undergoing their 2-week clinical neurosciences rotation at the Royal Hospitals Belfast were invited to participate in this study. A multi-method strategy was employed using a survey questionnaire comprising of closed and open-ended questions followed by semi-structured interviews to gain a greater 'in-depth' analysis of the potential contribution of neurosurgical theatre attendance to neuroscience teaching.

Results: Based on the completed survey responses of 22 students, the overall experience of neurosurgical theatre-based learning was a positive one. 'In-depth' analysis from semi-structured interviews indicated that students felt that some aspects of their neurosurgical theatre attendance could be improved. Better preparation such as reading up on the case in hand and an introduction to simple theatre etiquette to put the student at ease (in particular, for students who had never attended theatre previously), would improve the learning experience. In addition, having an expectation of what students are expected to learn in theatre making it more learning outcomes-based would probably make it feel a more positive experience by the student.

Conclusions: The vast majority of students acknowledged the positive learning outcomes of neurosurgical theatre attendance and felt that it should be made a mandatory component of the curriculum.

Revascularization versus medical therapy for renal-artery stenosis

Percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, yet evidence of a clinical benefit is limited.

Offshore wind power forecasting error and electricity market implications

Wind energy has been identified as key to the European Union’s 2050 low carbon economy. However, as wind is a variable resource and stochastic by nature, it is difficult to plan and schedule the power system under varying wind power generation. This paper investigates the impacts of offshore wind power forecast error on the operation and management of a pool-based electricity market in 2050. The impact of the magnitude and variance of the offshore wind power forecast error on system generation costs, emission costs, dispatch-down of wind, number of start-ups and system marginal price is analysed. The main findings of this research are that the magnitude of the offshore wind power forecast error has the largest impact on system generation costs and dispatch-down of wind, but the variance of the offshore wind power forecast error has the biggest impact on emissions costs and system marginal price. Overall offshore wind power forecast error variance results in a system marginal price increase of 9.6% in 2050.