MPS-ATLAS: A fast all-in-one code for synthesising stellar spectra

Context. Stellar spectral synthesis is essential for various applications, ranging from determining stellar parameters to comprehensive stellar variability calculations. New observational resources as well as advanced stellar atmosphere modelling, taking three dimensional effects from radiative magnetohydrodynamics calculations into account, require a more efficient radiative transfer. Aims. For accurate, fast and flexible calculations of opacity distribution functions (ODFs), stellar atmospheres, and stellar spectra, we developed an efficient code building on the well-established ATLAS9 code. The new code also paves the way for easy and fast access to different elemental compositions in stellar calculations. Methods. For the generation of ODF tables, we further developed the well-established DFSYNTHE code by implementing additional functionality and a speed-up by employing a parallel computation scheme. In addition, the line lists used can be changed from Kurucz’s recent lists. In particular, we implemented the VALD3 line list. Results. A new code, the Merged Parallelised Simplified ATLAS, is presented. It combines the efficient generation of ODF, atmosphere modelling, and spectral synthesis in local thermodynamic equilibrium, therefore being an all-in-one code. This all-in-one code provides more numerical functionality and is substantially faster compared to other available codes. The fully portable MPS-ATLAS code is validated against previous ATLAS9 calculations, the PHOENIX code calculations, and high-quality observations

Multiple antenna (MA) for cognitive radio based wireless mesh networks (CRWMNs): Spectrum Sensing (SS)

The concept of cognitive radio (CR) rings a big paradigm shift to the wireless communication domain. Extending this concept in to wireless mesh networks (WMN) results a CRWMN which alleviates the pragmatic spectrum congestion in the ISM bands. The assimilation of MAs technology in to CRWMN brings an astonishing system performance improvement. The use of MAs in WMN improves system capacity and reliability, increases coverage area and spectrum usage efficiency; and result in lower power consumption, better interference cancellation, efficient spectrum sensing, and spectrum sharing. In spite of the significant advantages, the use of multiple antennas has considerable limitations. In this paper, we investigate the challenges, opportunities, and the possible research directions that the cognitive radio network (CRN) in general and the CRWMN in particular experience while incorporating MAs to the system and its effect on spectrum sensing.Peer ReviewedPostprint (author's final draft