A solution to the MCSP problem considering physical layer degradations in transparent optical networks
In all-optical networks, the physical layer impairments cause a degradation in the transmitted signal. Sometimes, the degradation causes an inadmissible Optical Signal to Noise Ratio (OSNR), which is translated into blocking due to low quality of transmission. The Impairment Aware -- Routing and Wavelength Assignment (IA-RWA) should choose the route and wavelength considering the physical layer impairments. The Choice of the Best Combination among M Combinations of Shortest Paths (MCSP) problem consists of choosing the best of the shortest paths for a network topology aiming to reduce the blocking probability. This paper presents a pioneer study of the MCSPs problem assuming Amplified Spontaneous Emission (ASE), co-wavelength crosstalk, self-wavelength crosstalk, neighbor wavelength crosstalk, Polarization Mode Dispersion (PMD) and attenuations caused by fiber and devices. In this context, we propose a new routing algorithm that aims to resolve the MCSP problem considering the physical impairments.
Impact of physical layer impairments in all-optical networks
We investigate the impact of different physical impairments in the performance of all-optical networks. The physical impairments considered are the gain saturation and amplified spontaneous emission noise depletion in amplifiers, homodyne crosstalk in optical switches, four wave mixing and polarization mode dispersion in the transmission fibers. Our simulation results are presented in terms of blocking probability of requested calls as a function of network device parameters.
Investigation of scatter radiation of non-circular X-ray scan trajectories
Modern interventional X-ray devices are highly maneuverable and allow complex 3D imaging trajectories. New scan trajectories enable not only optimized object sampling but also introduce new approaches for dynamic 3D imaging. In this paper, we investigated the scatter radiation of two different scan trajectories. The scatter radiation was sampled by a rail setup with dosimeters at defined positions. After data analysis, contour maps were generated which show for four exemplary heights the scatter radiation distribution. The alternative scan trajectory showed smaller dose exposures at heights correlated to upper torso and head areas of a model physician. Keywords—Image acquisition, alternative scan trajectory, circular tomosynthesis, scatter radiation distribution