Derivation of Wave Loads for the Design of Oscillating Wave Surge Converters

This paper deals with the problem of estimating wave pressure loads acting on Oscillating Wave Surge Converters (OWSC) for assessment of fatigue on their components. Recent wave loading data issued from experimental testing of a 25th scale model of a box-shaped OWSC are here used to review the accuracy of the predictions made by an engineering method previously developed to derive wave pressure loads on OWSCs from experimental data. Predictions are shown underestimate wave pressure loads, and other methods subsequently developed are presented. A simplistic experimental method taking in consideration variations of the wetted surface area of the flap is shown to lead to relatively good estimates of wave pressure loads that could be used for fatigue calculations.

Effectiveness of a programme of exercise on physical function in survivors of critical illness following discharge from the ICU: study protocol for a randomised controlled trial (REVIVE)

Background: Following discharge home from the ICU, patients often suffer from reduced physical function, exercise capacity, health-related quality of life and social functioning. There is usually no support to address these longer term problems, and there has been limited research carried out into interventions which could improve patient outcomes. The aim of this study is to investigate the effectiveness and cost-effectiveness of a 6-week programme of exercise on physical function in patients discharged from hospital following critical illness compared to standard care.

Methods/Design: The study design is a multicentre prospective phase II, allocation-concealed, assessor-blinded, randomised controlled clinical trial. Participants randomised to the intervention group will complete three exercise sessions per week (two sessions of supervised exercise and one unsupervised session) for 6 weeks. Supervised sessions will take place in a hospital gymnasium or, if this is not possible, in the participants home and the unsupervised session will take place at home. Blinded outcome assessment will be conducted at baseline after hospital discharge, following the exercise intervention, and at 6 months following baseline assessment (or equivalent time points for the standard care group). The primary outcome measure is physical function as measured by the physical functioning subscale of the Short-Form-36 health survey following the exercise programme. Secondary outcomes are health-related quality of life, exercise capacity, anxiety and depression, self efficacy to exercise and healthcare resource use. In addition, semi-structured interviews will be conducted to explore participants’ perceptions of the exercise programme, and the feasibility (safety, practicality and acceptability) of providing the exercise programme will be assessed. A within-trial cost-utility analysis to assess the cost-effectiveness of the intervention compared to standard care will also be conducted.

Discussion: If the exercise programme is found to be effective, this study will improve outcomes that are meaningful to patients and their families. It will inform the design of a future multicentre phase III clinical trial of exercise following recovery from critical illness. It will provide useful information which will help the development of services for patients after critical illness.

Complexity of concern: Social acceptance of wind energy and the inevitability of dissensus

This presentation will explore the  role that social acceptance of onshore wind can play in understanding and progressing the low carbon transition in Europe. Although this is commonly perceived as arising simply from the overall level of renewable energy generated (and ‘dirty’ energy displaced), its significance goes well beyond this as it helps us understand some of the key issues facing the electricity sector as a social-technical system.  As such it is not only a matter of delivering the necessary infrastructure, but requires the long term mediation of complex multi-governmental arrangements involving a very wide range of actors. The interests of these actors engage hugely different timescales, geographic scales of concern and rationalities that make the arena of social acceptance a cauldron of complexity, mediating between overlapping and incompatible concerns. The presentation will briefly review the nature of some of these relationships and discuss what this means for how we conceive and act on the social acceptance of wind, and what this means for the long term low carbon transition

Hierarchical demand response using dantzig-wolfe decomposition

Demand Side Management (DSM) programmes are designed to shift electrical loads from peak times. Demand Response (DR) algorithms automate this process for controllable loads. DR can be implemented explicitly in terms of Peak to Average Ratio Reduction (PARR), in which case the maximum peak load is minimised over a prediction horizon by manipulating the amount of energy given to controllable loads at different times. A hierarchical predictive PARR algorithm is presented here based on Dantzig-Wolfe decomposition. © 2013 IEEE.

Fair charging strategies for EVs connected to a low-voltage distribution network

The development of smart grid technologies and appropriate charging strategies are key to accommodating large numbers of Electric Vehicles (EV) charging on the grid. In this paper a general framework is presented for formulating the EV charging optimization problem and three different charging strategies are investigated and compared from the perspective of charging fairness while taking into account power system constraints. Two strategies are based on distributed algorithms, namely, Additive Increase and Multiplicative Decrease (AIMD), and Distributed Price-Feedback (DPF), while the third is an ideal centralized solution used to benchmark performance. The algorithms are evaluated using a simulation of a typical residential low voltage distribution network with 50% EV penetration. © 2013 IEEE.

High-impedance metasurfaces with interwoven conductor patterns

High impedance metasurfaces (HIMSs) formed by interwoven conductor arrays are proposed. Bandwidth comparable with that of the basic square patches is achieved at an order of magnitude smaller unit cells. The presented structures are apt for small mobile terminals and low frequency applications.

Interwoven spiral arrays on ferrite-dielectric substrates for high-impedance metasurfaces

A high impedance metasurface (HIMS) composed of the arrays of intertwined planar spirals on thin (~0.1λ) ferrite-dielectric substrate is proposed. The HIMS exhibits fractional bandwidth in excess of 10% and excellent angular and polarisation stability of the circular polarised waves at oblique incidence.

Generalized Loopy 2U: A New Algorithm for Approximate Inference in Credal Networks

Credal nets generalize Bayesian nets by relaxing the requirement of precision of probabilities. Credal nets are considerably more expressive than Bayesian nets, but this makes belief updating NP-hard even on polytrees. We develop a new efficient algorithm for approximate belief updating in credal nets. The algorithm is based on an important representation result we prove for general credal nets: that any credal net can be equivalently reformulated as a credal net with binary variables; moreover, the transformation, which is considerably more complex than in the Bayesian case, can be implemented in polynomial time. The equivalent binary credal net is updated by L2U, a loopy approximate algorithm for binary credal nets. Thus, we generalize L2U to non-binary credal nets, obtaining an accurate and scalable algorithm for the general case, which is approximate only because of its loopy nature. The accuracy of the inferences is evaluated by empirical tests.