Coded Computation Against Processing Delays for Virtualized Cloud-Based Channel Decoding

The uplink of a cloud radio access network architecture is studied in which decoding at the cloud takes place via network function virtualization on commercial off-the-shelf servers. In order to mitigate the impact of straggling decoders in this platform, a novel coding strategy is proposed, whereby the cloud re-encodes the received frames via a linear code before distributing them to the decoding processors. Transmission of a single frame is considered first, and upper bounds on the resulting frame unavailability probability as a function of the decoding latency are derived by assuming a binary symmetric channel for uplink communications. Then, the analysis is extended to account for random frame arrival times. In this case, the trade-off between average decoding latency and the frame error rate is studied for two different queuing policies, whereby the servers carry out per-frame decoding or continuous decoding, respectively. Numerical examples demonstrate that the bounds are useful tools for code design and that coding is instrumental in obtaining a desirable compromise between decoding latency and reliability.Comment: 11 pages and 12 figures, Submitte

Audio-visual Rhetoric: Visualizing the Pattern Language of Film

Audio-visual Rhetoric is a knowledge domain for designers in theory and practice that is valid for all communicative actions through media that aim for persuasion. Within this domain, we introduce a framework for media analysis. We developed an Audio-Visual Pattern (AVP) language for film that is visualized within a notation system. This system shows auditory and visual parameters in order to reveal film’s rhetorical structure. We discuss related theories from pattern language and rhetoric and apply the AVP method to analyze 10 commercials. Keywords: Pattern Language, Film Analysis, Rhetoric, Emotion, Persuasion, Design Research</p

Probing weak dipole-dipole interaction using phase-modulated non-linear spectroscopy

Phase-modulated non-linear spectroscopy with higher harmonic demodulation has recently been suggested to provide information on many-body excitations. In the present work we theoretically investigate the application of this method to infer the interaction strength between two particles that interact via weak dipole-dipole interaction. To this end we use full numerical solution of the Schr\"odinger equation with time-dependent pulses. For interpretation purpose we also derive analytical expressions in perturbation theory. We find one can detect dipole-dipole interaction via peak intensities (in contrast to line-shifts which typically are used in conventional spectroscopy). We provide a detailed study on the dependence of these intensities on the parameters of the laser pulse and the dipole-dipole interaction strength. Interestingly, we find that there is a phase between the first and second harmonic demodulated signal, whose value depends on the sign of the dipole-dipole interaction.Comment: 12 pages, 8 figures, Supporting information provided with the source file

Physics and application of photon number resolving detectors based on superconducting parallel nanowires

The Parallel Nanowire Detector (PND) is a photon number resolving (PNR) detector which uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander pattern. PNDs were fabricated on 3-4 nm thick NbN films grown on MgO (TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. PNDs showed a counting rate of 80 MHz and a pulse duration as low as 660ps full width at half maximum (FWHM). Building the histograms of the photoresponse peak, no multiplication noise buildup is observable. Electrical and optical equivalent models of the device were developed in order to study its working principle, define design guidelines, and develop an algorithm to estimate the photon number statistics of an unknown light. In particular, the modeling provides novel insight of the physical limit to the detection efficiency and to the reset time of these detectors. The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed, and multiplication noise

Echo, not quotation: what conversation analysis reveals about classroom responses to heard poetry

This article applies conversation analysis to classroom talk-in-interaction where pupils respond to poetry they have heard. The phenomenon of repeating in discussion details from the poem, including patterns of delivery, is considered and named echo to distinguish it from quotation in writing. The phenomenon is significant to the pedagogy of literary study given the existing tacit and unexamined assumption that when pupils repeat textual details verbally this has equivalence with quotation in writing. Three episodes drawn from a single sequence of classroom interaction are presented together with a transcript of the stimulus heard poem. Each is accompanied by an interpretive commentary. It appears that echo in classroom discussions of poetry performs actions distinct from quotation in writing, for example that the acts of presenting and analysing textual detail occur simultaneously. The innovation of the research lies in the inclusion of the transcript-rendered poem as a turn in the sequence of interaction: as a verbally oriented method, conversation analysis provides an apt means of rendering response to poetry presented in the oral mode. More broadly, the discussion is consistent with the emergent popularity of conversation analysis as a method for considering classroom interactions with a view to reflecting on subtle aspects of learning