Game theory framework for MAC parameter optimization in energy-delay constrained sensor networks

Optimizing energy consumption and end-to-end (e2e) packet delay in energy-constrained, delay-sensitive wireless sensor networks is a conflicting multiobjective optimization problem. We investigate the problem from a game theory perspective, where the two optimization objectives are considered as game players. The cost model of each player is mapped through a generalized optimization framework onto protocol-specific MAC parameters. From the optimization framework, a game is first defined by the Nash bargaining solution (NBS) to assure energy consumption and e2e delay balancing. Secondy, the Kalai-Smorodinsky bargaining solution (KSBS) is used to find an equal proportion of gain between players. Both methods offer a bargaining solution to the duty-cycle MAC protocol under different axioms. As a result, given the two performance requirements (i.e., the maximum latency tolerated by the application and the initial energy budget of nodes), the proposed framework allows to set tunable system parameters to reach a fair equilibrium point that dually minimizes the system latency and energy consumption. For illustration, this formulation is applied to six state-of-the-art wireless sensor network (WSN) MAC protocols: B-MAC, X-MAC, RI-MAC, SMAC, DMAC, and LMAC. The article shows the effectiveness and scalability of such a framework in optimizing protocol parameters that achieve a fair energy-delay performance trade-off under the application requirements

The incidence of clinical fractures in adults aged 50 years and older in Spain

Objective. The aim of this study was to quantify the incidence of all clinical fractures, including traumatic and fragility fractures, in patients aged 50 years and older, and to describe their distribution by fracture location, sex and age. Methods. The incidence of clinical fractures at 10 hospitals in Catalonia, with a reference population of 3 155 000 inhabitants, was studied. For 1 week, from 30 May to 5 June 2016, we reviewed the discharge reports of the Traumatology section of the Emergency Department to identify all fractures diagnosed in patients ≥50 years of age. As a validation technique, data collection was carried out for 1 year at one of the centres, from 1 December 2015 to 30 November 2016. The fracture incidence, including the 95% CI, was estimated for the entire sample and grouped by fracture type, location, sex and age. Results. A total of 283 fractures were identified. Seventy per cent were in women, with a mean age of 72 years. The overall fracture incidence was 11.28 per 1000 person-years (95% CI: 11.10, 11.46), with an incidence of traumatic and fragility fractures of 4.15 (95% CI: 4.04, 4.26) and 7.13 per 1000 person-years (95% CI: 6.99, 7.28), respectively. The incidence of fractures observed in the validation sample coincided with that estimated for the whole of Catalonia. The most common fragility fractures were of the hip, forearm, humerus and vertebrae. Conclusion. The results of this study are the first to estimate the incidence of clinical fragility fractures in Spain, grouped by location, age and sex

Modulator-controlled synthesis of microporous STA-26, an interpenetrated 8,3-connected zirconium MOF with the the-i topology, and its reversible lattice shift

The authors acknowledge the support of the EPSRC/St Andrews Criticat CDT (RRRP, PAW) and the European Community Seventh Framework Program (FP7/2007-2013) number 608490 (project M4CO2) (KKC, MYM, KIH, PAW). SEA would like to thank the Royal Society and Wolfson Foundation for a merit award. This research made use of the Balena High Performance Computing (HPC) Service at the University of Bath. The research data (and/or materials) supporting this publication can be accessed at DOI: http://dx.doi.org/10.17630/6ffeed8a-e75f-4648-968f-3ed32a94e9a0.A fully interpenetrated 8,3-connected zirconium MOF with the the-i topology type, STA-26 (St Andrews porous material-26), has been prepared using the 4,4',4"-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoate (TMTB) tritopic linker with formic acid as a modulating agent. In the as-prepared form STA-26 possesses Im-3m symmetry compared with the Pm-3m symmetry of the non-interpenetrated analogue, NU-1200, prepared using benzoic acid as a modulator. Upon removal of residual solvent there is a shift between the interpenetrating lattices and a resultant symmetry change to Cmcm which is fully reversible. This is observed by X-ray diffraction and 13C MAS NMR is also found to be remarkably sensitive to the structural transition. Furthermore, heating STA-26(Zr) in vacuum dehydroxylates the Zr6 nodes leaving coordinatively unsaturated Zr4+ sites, as shown by IR spectroscopy using CO and CD3CN as probe molecules. Nitrogen adsorption at 77 K together with grand canonical Monte Carlo simulations confirms a microporous, fully interpenetrated, structure with pore volume 0.53 cm3 g−1 while CO2 adsorption at 196 K reaches 300 cm3 STP g−1 at 1 bar. While the pore volume is smaller than that of its non-interpenetrated mesoporous analogue, interpenetration makes the structure more stable to moisture adsorption and introduces shape selectivity in adsorption.PostprintPeer reviewe

Comparing the Institutional and Organizational Design of Currency Boards in Transition Countries

The article carries out a comparative and descriptive analysis of the currency boards that have been introduced in three East European countries: Bulgaria, Estonia, and Lithuania. The initial conditions and specific features of currency boards in these three countries are presented in detail. There is also a focus on the institutional, organizational, legal, and political characteristics of these currency boards. Special attention is given to deviations from the orthodox currency board framework. Currency boards in the countries under consideration limit the scope for monetary policy, due to the presence of atypical balance sheet items and the employment of a number of monetary policy instruments. The comparison of currency board operation in the three countries reveals significant differences in the historical background of currency board adoption, institutional design, and overall macroeconomic framework. This observation does not fit completely with the generally accepted view that currency boards in the three transition economies function in a similar pattern and that the differences among them are insignificant. The article suggests some new directions for the analysis of currency boards in transition countries.