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21.
An original wireless video transmission scheme called SoftCast has been recently proposed to deal with the issues encountered in conventional wireless video broadcasting systems (e.g. cliff effect). In this paper, we evaluate and optimize the performance of the SoftCast scheme according to the transmitted video content. Precisely, an adaptive coding mechanism based on GoP-size adaptation, which takes into account the temporal information fluctuations of the video, is proposed. This extension denoted Adaptive GoP-size mechanism based on Content and Cut detection for SoftCast (AGCC-SoftCast) significantly improves the performance of the SoftCast scheme. It consists in modifying the GoP-size according to the shot changes and the spatio-temporal characteristics of the transmitted video. When hardware capacities, such as buffer or processor performance are limited, an alternative method based only on the shot changes detection (AGCut-SoftCast) is also proposed. Improvements up to 16 dB for the PSNR and up to 0.55 for the SSIM are observed with the proposed solutions at the cut boundaries. In addition, temporal visual quality fluctuations are reduced under 1dB in average, showing the effectiveness of the proposed methods. 相似文献
22.
Ma Cui-Xia Song Jian-Cheng Zhu Qian Maher Kevin Huang Ze-Yuan Wang Hong-An 《计算机科学技术学报》2020,35(3):576-591
Journal of Computer Science and Technology - Emotion plays a crucial role in gratifying users’ needs during their experience of movies and TV series, and may be underutilized as a framework... 相似文献
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To form a high-performance video quality predictor, we developed a framework for full-reference (FR) video quality assessment that integrates Spatio-temporal slice analysis (STS) to create a high-performance predictor of video quality. However, both gradient and Gabor are spatial–temporal structural capturers used for the simultaneous extraction of both spatial and temporal features. In this paper, we proposed a novel VQA algorithm via a joint model of gradient magnitude and Gabor features (JMG) between the STS images of the reference videos and their distorted counterparts to assess the degradation of video quality effectively. Firstly, gradient magnitude and the Gabor filter were constructed to extract the spatiotemporal features of the video sequence. However, the two-feature model combined to predict the perceptual quality of frames. This new proposed VQA model is known as the horizontal and time STS (HT-JMG) model. To further investigate the influence of spatial dissimilarity, we combined the frame-by-frame spatial T-JMG(S) factor with the HT-JMG and propose another VQA model, called the time, horizontal, and vertical STS (THV-JMG) model. Finally, the results of the experiment showed that the proposed method has a strong correlation with subjective perception and is competitive with state-of-the-art full reference VQA models. 相似文献
25.
Lukáš Kolek Vít Šisler Patrícia Martinková Cyril Brom 《Journal of Computer Assisted Learning》2021,37(5):1348-1369
This study investigates a video game's effects on implicit and explicit attitudes towards depicted historical events in the short- and long-term on a sample of 148 young adults. We used, as an intervention tool, a serious game Czechoslovakia 38–89: Borderlands that deals with the expulsion of the Sudeten Germans from the former Czechoslovakia after the WWII. Results showed more negative pretest-posttest explicit attitude changes towards the expulsion on a general level (d = −0.34) and a specific level (d = −0.53) compared to the control group. Over the long-term, group differences in attitude change remained significant for the specific level (d = −0.44), but not for general one (d = −0.16). Exploratory analysis on the item level indicated that especially attitudes towards the expulsion's (un)fairness were affected by the game. However, no significant changes were found in implicit attitudes in the experimental group. This study is the first of such scale to empirically investigate video games' effects on a society's historical awareness. 相似文献
26.
数字经济时代,新技术、新产业、新业态、新模式加速孕育,网络市场竞争态势愈加复杂、多变,监管创新成为重要课题。网络市场监管工作应当确立稳定、可预期的监管原则,并落实好包容审慎、事中事后监管、协同监管等原则;对关系到国家安全、社会稳定和公众生命健康等底线性问题,监管不能缺位,而应继续严格审查监管。从创新监管原则的宏观研究,以及大数据监管、提升电子取证能力等监管手段的具体研究等维度,对监管创新进行了深度思考。 相似文献
27.
With the evolution of video surveillance systems, the requirement of video storage grows rapidly; in addition, safe guards and forensic officers spend a great deal of time observing surveillance videos to find abnormal events. As most of the scene in the surveillance video are redundant and contains no information needs attention, we propose a video condensation method to summarize the abnormal events in the video by rearranging the moving trajectory and sort them by the degree of anomaly. Our goal is to improve the condensation rate to reduce more storage size, and increase the accuracy in abnormal detection. As the trajectory feature is the key to both goals, in this paper, a new method for feature extraction of moving object trajectory is proposed, and we use the SOINN (Self-Organizing Incremental Neural Network) method to accomplish a high accuracy abnormal detection. In the results, our method is able to shirk the video size to 10% storage size of the original video, and achieves 95% accuracy of abnormal event detection, which shows our method is useful and applicable to the surveillance industry. 相似文献
28.
Extraction chromatography (EC) resins are widely used in analytical radiochemical separations, in particular for actinide separation. However, there is currently limited choice for separation of americium using EC, with DGA (N,N,N′,N′-tetra-n-octyldiglycolamide) resin being the preferred option. Here, we describe preparation and testing of a covalently-linked EC resin utilising a triazine soft N-donor (Me4BTPhen) extractant for americium extraction. The resin was generated by conjugation of a Me4BTPhen derivative with poly(vinylbenzyl) chloride to generate PVB–Me4BTPhen. PVB–Me4BTPhen was shown to extract americium from a complex matrix simulating nuclear forensic samples, and containing lanthanides, actinides and matrix elements with high Am (III) recovery (>90%) and low extraction of other elements, and provides an alternative to the currently used BTPhen liquid–liquid separation process for Am (III) extraction. 相似文献
29.
为了解决复杂场景下传统的运动目标检测问题, 利用证据推理—–谨慎有序加权平均方法(COWA-ER), 提出一种综合使用混合高斯、均值滤波和码本的多方法融合的检测方法. 该融合检测算法以上述3 种检测方法为准则建立一个多准则决策框架, 通过双阈值检测法来表征检测过程中的不确定性, 最终利用COWA-ER 方法进行决策级融合, 实现多种方法的优势互补. 实验表明, 所提出的融合检测算法具有更理想的目标检测效果, 能有效应对诸如阴影及光照突变等问题对检测性能的影响.
相似文献30.
文章阐述了视频会议的重要意义、发展趋势、分类及组网结构等,并结合上海燃气浦东销售有限公司的视频会议系统,介绍了实际应用情况。 相似文献