Joint gateway selection, transmission slot assignment, routing and power control for wireless mesh networks

Cataloged from PDF version of article.Wireless mesh networks (WMNs) provide cost effective solutions for setting up a communications network over a certain geographic area. In this paper, we study strategic problems of WMNs such as selecting the gateway nodes along with several operational problems such as routing, power control, and transmission slot assignment. Under the assumptions of the physical interference model and the tree-based routing restriction for traffic flow, a mixed integer linear programming (MILP) formulation is presented, in which the objective is to maximize the minimum service level provided at the nodes. A set of valid inequalities is derived and added to the model in an attempt to improve the solution quality. Since the MILP formulation becomes computationally infeasible for larger instances, we propose a heuristic method that is aimed at solving the problem in two stages. In the first stage, we devise a simple MILP problem that is concerned only with the selection of gateway nodes. In the second stage, the MILP problem in the original formulation is solved by fixing the gateway nodes from the first stage. Computational experiments are provided to evaluate the proposed models and the heuristic method. (C) 2013 Elsevier Ltd. All rights reserved

Use of an antibiotic growth promoter and two herbal natural feed additives with and without exogenous enzymes in wheat based broiler diets

No Abstract. South African Journal of Animal Science Vol. 35 (1) 2005: pp.61-7

Stability analysis of second order pulsed Raman laser in dispersion managed systems

8siWavelength tunable synchronous pulse sources are highly desirable for spectroscopy and optical diagnostics. The common method to generate short pulses in the fiber is the use of nonlinear induced spectral broadening which result in soliton shaping in anomalous dispersion regime. However, to generate ultra-short pulses, broadband gain mechanism is also required. In recent years, Raman fiber lasers have retrieved strong interest due to their capability of serving as pump sources in gain-flattened amplifiers for optical communication systems. The fixed-wavelength Raman lasers have been widely studied in the last years, but recently, much focus has been on the multi wavelength tunable Raman fiber lasers which generate output Stokes pulses in a broad wavelength range by so called cascaded stimulated Raman scattering. In this paper we investigate synchronous 1st and 2nd order pulsed Raman lasers that can achieve frequency spacing of up to 1000cm-1 that is highly desired for CARS microscopy. In particular, analytical and numerical analysis of pulsed stability derived for Raman lasers by using dispersion managed telecom fibers and pumped by 1530nm fiber lasers. We show the evolution of the 1st and 2nd order Stokes signals at the output for different pump power and SMF length (determines the net anomalous dispersion) combinations. We investigated the stability of dispersion managed synchronous Raman laser up to second order both analytically and numerically. The results show that the stable 2nd order Raman Stokes pulses with 0.04W to 0.1W peak power and 2ps to 3.5ps pulse width can be achieved in dispersion managed systemopenopenS. K. Kalyoncu; S. Gao; E.K. Tien; Y. Huang; D. Yildirim; E. Adas; S. Wabnitz; O. BoyrazS. K., Kalyoncu; S., Gao; E. K., Tien; Y., Huang; D., Yildirim; E., Adas; Wabnitz, Stefan; O., Boyra

New approximations for the cone of copositive matrices and its dual

We provide convergent hierarchies for the cone C of copositive matrices and its dual, the cone of completely positive matrices. In both cases the corresponding hierarchy consists of nested spectrahedra and provide outer (resp. inner) approximations for C (resp. for its dual), thus complementing previous inner (resp. outer) approximations for C (for the dual). In particular, both inner and outer approximations have a very simple interpretation. Finally, extension to K-copositivity and K-complete positivity for a closed convex cone K, is straightforward.Comment: 8

2-Chloro-7,8,9,10-tetra­hydro­cyclo­hepta­[b]indol-6(5H)-one

In the title mol­ecule, C13H12ClNO, the dihedral angle between the benzene and pyrrole rings is 1.38 (9)°. The cyclo­heptene ring adopts a distorted twist chair and sofa conformation. Inter­molecular N—H⋯O hydrogen bonds form an R 2 2(10) loop in the crystal packing. Further, weak C—H⋯O and C—H⋯π (involving the benzene ring) inter­actions are found in the crystal structure

Small Fermi energy and phonon anharmonicity in MgB_2 and related compounds

The remarkable anharmonicity of the E_{2g} phonon in MgB_2 has been suggested in literature to play a primary role in its superconducting pairing. We investigate, by means of LDA calculations, the microscopic origin of such an anharmonicity in MgB_2, AlB_2, and in hole-doped graphite. We find that the anharmonic character of the E_{2g} phonon is essentially driven by the small Fermi energy of the sigma holes. We present a simple analytic model which allows us to understand in microscopic terms the role of the small Fermi energy and of the electronic structure. The relation between anharmonicity and nonadiabaticity is pointed out and discussed in relation to various materials.Comment: 5 pages, 2 figures replaced with final version, accepted on Physical Review

Elucidating the Thermal Response of W-Ta Alloys with Transient Grating Spectroscopy, TEM and Atomistic Simulation

Critical for tungsten alloys’ use as plasma-facing component materials are their thermal response and their evolution under irradiation. Utilising Transient Grating Spectroscopy, TEM, and Molecular Dynamics, this study sought to probe these changes in W, W6Ta, and W11Ta alloys. Irradiation with 12.25 MeV W6+ ions was carried out in the CLASS facility at MIT at a temperature of 500°C for doses of 0.1, 0.3, and 1.0 dpa. The alloys’ thermal diffusivity was found to degrade less than that of the pure counterpart. Molecular Dynamics simulation revealed that this was due to a reduced defect population below TEM resolution. Despite these alloys showing enhanced resilience to thermal property degradation, it was found that the absolute values of their thermal diffusivity remained below that of pure tungsten. This study highlighted a key interplay between enhancing radiation tolerance with alloying additions and the alloy additions’ initial negative effect on the thermal response and thus in-service behaviour

Strategies to promote children\u27s school based physical activity : Transform-Us! Mid-intervention findings

Session 202 - School based interventions: paper 276This journal suppl. entitled: Be Avtive 2012Many children engage in suboptimal levels of PA despite the associated health risks. Schools (n=20) in the Transform-Us! program were randomized to one of four intervention arms that target increases in children’s PA (PA), reductions in sedentary behavior (SB), both behaviors (SB+PA) or control current practice (C). This examination focuses on the PA promotion strategies employed in the PA and SB+PA arms compared with the C arm. To promote children’s PA each PA and SB+PA class was provided with sporting and circus equipment; asphalt line markings were installed at the school; and teachers were asked to encourage PA. Grade 3 children at participating schools were invited to take part in evaluation assessments including the completion of a self-report survey. Findings from the PA promotion strategy questions at baseline (Feb–June 2010), and T2 (Nov/Dec) are reported here. Children (n=425, 55% female) were asked to respond (yes/no) to five items asking about social support for PA from their class teacher, which were then summed to create a ‘teacher social support’ scale. Children were also asked to indicate if ‘there are markings on the walls or on the school playground to help us play games’ (perceived availability of line markings); if they are ‘allowed to use school sports equipment during recess and lunch breaks’ (perceived accessibility of sports equipment); and how much they like ‘the areas to play in at school’ using a 5-point Likert scale (perceived school environment). Between baseline and T2, teacher social support increased in both PA (1.7[1.4] vs 2.1[1.4]) and SB arms (1.9[1.4] vs 2.4[1.4) but declined in C (2.0[1.4] vs 1.7[1.5]). For all three arms, increases were seen in perceived availability of line markings (PA: 53.2% vs 69.4%; SB+PA: 59.3% vs 71.4%; C: 60.0% vs 69.8%); perceived accessibility of sport equipment (PA: 87.7% vs 97.2%: SB+PA: 80.7 vs 94%; C: 85.4% vs 97.6%); and perceived school environment (PA: 1.44[0.9] vs 1.42[0.8]; SB+PA: 1.5[0.8] vs 1.6[0.7]; C: 1.4[0.9] vs 1.5[0.7]) between baseline and T2. All findings were significant at a 1% probability level. At the mid-intervention time point, findings suggest that PA strategies have increased perceived availability of line markings, accessibility of sport equipment, and perceived school environment in children allocated to the PA and SB+PA arms. However, there were also unexpected increases in the C arm for three out of four items. Post-intervention findings will add to these preliminary findings

Field Dependence of Electronic Specific Heat in Two-Band Superconductors

The vortex structure is studied in light of MgB$_2$ theoretically based on a two-band superconducting model by means of Bogoliubov-de Gennes framework. The field dependence of the electronic specific heat coefficient $\gamma (H)$ is focused. The exponent $\alpha$ in $\gamma (H)\propto H^{\alpha}$ is shown to become smaller by adjusting the gap ratio of the two gaps on the major and minor bands. The observed extremely small value $\alpha\sim 0.23$ could be explained reasonably well in this two-band model with the gap ratio $\sim 0.3$.Comment: 5 pages, 4 figures, to be published in J. Phys. Soc. Jp