As an increasingly popular flow metering technology, Coriolis mass flowmeter exhibits high measurement accuracy under single-phase flow condition and is widely used in the industry. However, under complex flow conditions, such as two-phase flow, the measurement accuracy is greatly decreased due to various factors including improper signal processing methods. In this study, three digital signal processing methods—the quadrature demodulation (QD) method, Hilbert method, and sliding discrete time Fourier transform method—are analyzed for their applications in processing sensor signals and providing measurement results under gas-liquid two-phase flow condition. Based on the analysis, specific improvements are applied to each method to deal with the signals under two-phase flow condition. For simulation, sensor signals under single- and two-phase flow conditions are established using a random walk model. The phase difference tracking performances of these three methods are evaluated in the simulation. Based on the digital signal processor, a converter program is implemented on its evaluation board. The converter program is tested under single- and two-phase flow conditions. The improved signal processing methods are evaluated in terms of the measurement accuracy and complexity. The QD algorithm has the best performance under the single-phase flow condition. Under the two-phase flow condition, the QD algorithm performs a little better in terms of the indication error and repeatability than the improved Hilbert algorithm at 160, 250, and 420 kg/h flow points, whereas the Hilbert algorithm outperforms the QD algorithm at the 600 kg/h flow point.

The paper explores the relay-assisted IVC (inter-vehicular communication) systems with double-Rayleigh fading V2V (vehicle-to-vehicle) links for both APA (access point assisted) and VA (vehicle assisted) schemes. The OPA (optimal power allocation) solutions are derived through maximizing source-to-destination channel capacity assuming amplify-and-forward relaying. Furthermore, the outage performance is discussed and the lower bounds on outage probabilities at medium to high SNRs (signal-to-noise ratios) are presented for both APA and VA systems. Simulations manifest that the outage performance can be improved about 2dB gains through OPA method over EPA (equal power allocation) solution and the lower bounds coincide with the exact outage probabilities well at medium SNRs. These bounds can be used to evaluate the outage performance of the cooperative IVC systems roughly.