To combat the detrimental effects of the variability in wireless channels, we consider cross-layer rate adaptation. We study communication systems that utilize the limited feedback in the form of linklayer Automatic Repeat-reQuest (ARQ) to maximize the physical-layer transmission rate, subject to a certain upper bound on the expected packet error rate. We assume that there is no knowledge of th...

BACKGROUND The major cat allergen, Fel d 1, is a tetrameric glycoprotein composed of 2 heterodimers. Polymorphisms in this allergen are well documented. Recent work shows that Fel d 1 samples can contain core fragments of variable immunoreactivity. OBJECTIVES Our objective was to compare Fel d 1 polymorphism in cat extracts and house dust, which is used as an indicator of allergen exposure an...

We examine the capacity of beamforming over a block Rayleigh fading Multi-Input/Multi-Output (MIMO) channel with finite training for channel estimation and limited feedback. A fixed-length packet is assumed, which is spanned by T training symbols, B feedback bits, and the data symbols. The training symbols are used to obtain a Minimum Mean Squared Error (MMSE) estimate of the channel matrix. Gi...

Harmonic lasing is a possible mode of operation of X-ray FEL user facilities that allows us to provide brilliant beams of higher energy photons for user experiments. Another useful application of harmonic lasing is the so-called harmonic lasing self-seeded free electron laser (HLSS FEL) that allows the improvement of spectral brightness of these facilities. In the past, harmonic lasing has been...

The intensity of undulator radiation, not amplified by the FEL interaction, can be larger than the maximum FEL signal in the case of an X-ray FEL. In the commissioning of a SASE FEL it is essential to extract an amplified signal early to diagnose eventual misalignment of undulator modules or errors in the undulator field strength. We developed a numerical code to calculate the radiation pattern...