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Perceptual Quality Driven Frame-Rate Selection (PQD-FRS) for High-Frame-Rate Video
Huang, Qin,Jeong, Se Yoon,Yang, Shanglin,Zhang, Dichen,Hu, Sudeng,Kim, Hui Yong,Choi, Jin Soo,Kuo, C.-C. Jay IEEE 2016 IEEE transactions on broadcasting Vol.62 No.3
<P>Video of higher frame rates (HFR) reduces the visual artifact in large screen display at the cost of a higher coding bit rate (or transmission bandwidth). In this work, we propose a perceptual quality driven frame rate selection (PQD-FRS) method that assigns a time-varying frame rate to a sequence so as to reduce its transmission cost. The objective of the PQD-FRS method is to offer perceptually indistinguishable experience for a certain percentage of viewers. We first conduct a subjective test to characterize the relationship between human perceived quality and video contents, and build a frame-rate-dependent video quality assessment dataset to serve as the ground truth. Then, we use a machine learning approach for the design of the key module of the PQD-FRS method, called the 'satisfied user ratio (SUR) prediction.' The SUR prediction module predicts the percentage of satisfied viewers, who cannot differentiate video quality of a lower and HFR, using the support vector regression. It is confirmed by experimental results that the proposed SUR module can offer a so highly accurate prediction that the PQD-FRS system can dynamically assign a proper frame rate to video without any perceptual quality degradation for a majority of viewers.</P>
Design of vortex finder structure for decreasing the pressure drop of a cyclone separator
Yaquan Sun,Junzhi Yu,Weibing Wang,Shanglin Yang,Xue Hu,Jingan Feng 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5
The structure of the vortex finder has an important influence on the pressure drop and separation efficiency of a cyclone, which mainly governs the separation process. In this paper, the traditional vortex finder is slotted on side wall and its bottom is closed, i.e., a slotted vortex finder. The impact of slotted vortex finder on the separation performance of a cyclone is explored by using numerical simulation and experimental validation. Specifically, the gas phase is studied by the Reynolds stress model (RSM), and the particle phase is simulated by the discrete phase model (DPM). The simulation results are in good agreement with the experimental results, revealing higher prediction accuracy. The results indicate that the slotted vortex finder can effectively suppress the generation of the downward swirling flow at the center of the vortex finder and decrease the turbulence intensity at the bottom of the vortex finder and the outer vortex, thereby decreasing the energy loss and increasing the separation efficiency. When the slot length is 0.2De, the slotted vortex finder can reduce the pressure drop by 143.33 Pa while increasing the collection efficiency by 5.51%.