Melken und Kälber säugen – geht das?

In organic dairy farms, calves stay with their mother usually for two days after calving. This is not different from conventional dairy farms. During the last years the interest to alter this fact has steadily increased. Farmers expect an improvement of the health of the calves and to spare labour time as well: calves get their milk at the right time with the right temperature and a low content of bacteria. However, suckling influences the process of machine milking and the milk quality, too. This study investigated these correlations. Cows – suckling and milking – were compared with other cows which had no or only reduced contact to their offspring. Every group contained ten cows. Over a period of 8 weeks milk flow curves were weekly gained. Quarter-foremilk-samples for cyto-bacteriological analysis were collected every 14 days. The results revealed a clear effect of the suckling on machine milking: 25% of all milkings showed bimodal-ities. Only 10% and 5% of the milk flow curves of cows without and with reduced calf contact, respectively, were bimodal. The mean milk loss was 5.3 kg per cow and milking when the calves had the opportunity to suckle after milking. This means a daily loss of approximately 12 kg milk per cow and day, which is not going to the market. The fat content was reduced: the milk of the suckler cows contained 1% less fat than the milk of the other two groups of cows. The udder health of cows did not change. Also the behaviour of the cows during milking did not differ. The experiments indicated that suckling after machine milking influences the milking process. The alveolar milk can not be removed completely by the milking machine. A remarkable amount of milk remains in the udder to guarantee the feed of the calves. Further investigations should focus on suckling prior to milking to avoid the negative effects on machine milking

Experimental investigation of a 16-dimensional modulation format for long-haul multi-core fiber transmission

We experimentally investigate a 16-dimensional modulation format applicable to multi-core fiber transmission, and demonstrate over 14,000 km transmission for a BER of 1E-3, a 55 % improvement in reach compared to DP-BPSK for the same spectral efficiency

Pilot-Aided Joint-Channel Carrier-Phase Estimation in Space-Division Multiplexed Multicore Fiber Transmission

The performance of pilot-aided joint-channel carrier-phase estimation (CPE) in space-division multiplexed multicore fiber (MCF) transmission with correlated phase noise is studied. To that end, a system model describing uncoded MCF transmission where the phase noise comprises a common laser phase noise, in addition to core- and polarization-specific phase drifts, is introduced. It is then shown that the system model can be regarded as a special case of a multidimensional random-walk phase-noise model. A pilot-aided CPE algorithm developed for this model is used to evaluate two strategies, namely joint-channel and per-channel CPE. To quantify the performance differences between the two strategies, their respective phase-noise tolerances are assessed through Monte Carlo simulations of uncoded transmission for different modulation formats, pilot overheads, laser linewidths, numbers of spatial channels, and degrees of phase-noise correlation across the channels. For 20 GBd transmission with 200 kHz combined laser linewidth and 1% pilot overhead, joint-channel CPE yields up to 3.4 dB improvement in power efficiency or 25.5% increased information rate. Moreover, through MCF transmission experiments, the system model is validated and the strategies are compared in terms of bit-error-rate performance versus transmission distance for uncoded transmission of different modulation formats. Up to 21% increase in transmission reach is observed for 1% pilot overhead through the use of joint-channel CPE

Real-time, Software-Defined, GPU-Based Receiver Field Trial

We demonstrate stable real-time operation of a software-defined, GPU-based receiver over a metropolitan network. Massive parallelization is exploited for implementing direct-detection and coherent Kramers-Kronig detection in real time at 2 and 1 GBaud, respectively.Comment: Accepted for presentation at the European Conference on Optical Communications (ECOC) 202

Field Trial of a Flexible Real-time Software-defined GPU-based Optical Receiver

We introduce a flexible, software-defined real-time multi-modulation format receiver implemented on an off-the-shelf general-purpose graphics processing unit (GPU). The flexible receiver is able to process 2 GBaud 2-, 4-, 8-, and 16-ary pulse-amplitude modulation (PAM) signals as well as 1 GBaud 4-, 16- and 64-ary quadrature amplitude modulation (QAM) signals, with the latter detected using a Kramers-Kronig (KK) coherent receiver. Experimental performance evaluation is shown for back-to-back. In addition, by using the JGN high speed R&D network testbed, performance is evaluated after transmission over 91 km field-deployed optical fiber and reconfigurable optical add-drop multiplexers (ROADMs).Comment: Accepted for publication at Journal of Lightwave Technology, already available via JLT Early Access, see supplied DOI. This v2 version of the article is improved w.r.t. v1 after JLT peer-review. This article is a longer journal version of the conference paper: S.P. van der Heide, et al., Real-time, Software-Defined, GPU-Based Receiver Field Trial, ECOC 2020 paper We1E5, also via arXiv:2010.1433

Real-time transmission of geometrically-shaped signals using a software-defined GPU-based optical receiver

A software-defined optical receiver is implemented on an off-the-shelf commercial graphics processing unit (GPU). The receiver provides real-time signal processing functionality to process 1 GBaud minimum phase (MP) 4-, 8-, 16-, 32-, 64-, 128-ary quadrature amplitude modulation (QAM) as well as geometrically shaped (GS) 8- and 128-QAM signals using Kramers-Kronig (KK) coherent detection. Experimental validation of this receiver over a 91 km field-deployed optical fiber link between two Tokyo locations is shown with detailed optical signal-to-noise ratio (OSNR) investigations. A net data rate of 5 Gbps using 64-QAM is demonstrated.</p

Master-slave carrier recovery for M-QAM multicore fiber transmission

Master-slave carrier recovery is a digital signal processing technique that uses correlated phase noise in multi-channel receivers to eliminate redundant carrier recovery blocks. In this paper we experimentally investigate the performance of master-slave carrier recovery for multicore fiber transmission in the presence of inter-channel nonlinear interference. Using a triple parallel loop setup we jointly receive three spatial channels in a 7-core fiber for transmission distances of up to 1600 km. We find that an increased launch power causes a moderate penalty on the slave channels. Furthermore, we study the penalty from a non-zero inter-core skew