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1.
JI Xin POLLIN Sofie LENOIR Gregory LAFRUIT Gauthier DEJONGHE Antoine CATTHOOR Francky 《浙江大学学报(A卷英文版)》2006,7(Z1)
This paper introduces a video application-aware cross-layer framework for joint performance-energy optimization, considering the scenario of multiple users upstreaming real-time Motion JPEG2000 video streams to the access point of a WiFi wireless local area network and extends the PHY-MAC run-time cross-layer scheduling strategy that we introduced in (Mang-haram et al., 2005; Pollin el al., 2005) to also consider congested network situations where video packets have to be dropped. We show that an optimal solution at PHY-MAC level can be highly suboptimal at application level, and then show that making the cross-layer framework application-aware through a prioritized dropping policy capitalizing on the inherent scalability of Motion JPEG2000 video streams leads to drastic average video quality improvements and inter-user quality variation reductions of as much as 10 dB PSNR, without affecting the overall energy consumption requirements. 相似文献
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INTRODUCTION Ad-hoc networks are attractive owing to their self-organizing nature and absence of a fixed infra- structure. They are particularly suited for communi- cation in disaster-affected areas, coordinating military operations, and sensing environmental conditions With the growing availability of supporting hardware and decreasing equipment cost, ad-hoc networking based applications are proliferating. Meshes of wire- less nodes are being deployed in cities and housing communities to… 相似文献
3.
KATSAGGELOS Aggelos K. 《浙江大学学报(A卷英文版)》2006,7(5):801-810
INTRODUCTION Video streaming is becoming one of the major driving forces of next generation wireless networks. For the currently deployed cellular networks, the practical data rates are not enough to support full rate, high quality video applications. As a result, many research efforts have been devoted to adapting video content to reconcile the conflict between the high demand of video quality and the limited wireless communication resources among users. A large body of literature utiliz… 相似文献
4.
Classical unequal erasure protection schemes split data to be protected into classes which are encoded independently. The unequal protection scheme presented in this paper is based on an erasure code which encodes all the data together according to the existing dependencies. A simple algorithm generates dynamically the generator matrix of the erasure code according to the packets streams structure, i.e., the dependencies between the packets, and the rate of the code. This proposed erasure code was applied to a packetized MPEG4 stream transmitted over a packet erasure channel and compared with other classical protection schemes in terms of PSNR and MOS. It is shown that the proposed code allows keeping a high video quality-level in a larger packet loss rate range than the other protection schemes. 相似文献
5.
CHEN Zhi-kui 《浙江大学学报(A卷英文版)》2006,7(5):910-918
INTRODUCTION Recommendation H.264 was approved by ITU-T in May 2003 and the approved draft specifi cation is available for public review (Wiegand, 2003) The H.264 video codec has a very broad application range that covers all forms of digital compressed video from low bit rate Internet streaming applica tions to HDTV broadcast and digital cinema applica tions with near lossless coding. About 50% band width would be saved by using H.264 when compared to the existing most efficient com… 相似文献
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TANIYAMA Kenta MORII Takeshi KOIZUMI Shinya NOGUCHI Kazuhiro KOTANI Yukihiro KATTO Jiro 《浙江大学学报(A卷英文版)》2006,7(Z1)
We propose an on-demand multiparth routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routing protocols extended from AODV which is a well-known single path routing protocol. Multipath routing protocols indicate good performance in the reduction of route discovery latency and unnecessary routing packets in simulations. We show that the route establishment using source route lists provided by us (Hu and Johnson, 2002) can reduce the route discovery latency, select stable routes automatically, and work well for live video streaming without limitation of the hop count based approaches. We evaluate this proposed method compared with the original AODV by using eight laptop PCs and demonstrate live streaming experiments. 相似文献
7.
INTRODUCTION Real-time video transport over wireless Internet faces many challenges due to the heterogeneous en- vironment including wireline and wireless networks. Fig.1 shows a typical end-to-end video transport in- volving wireline and wireless networks. The video transport may suffer from many problems such as wireline network congestion and wireless multi-path fading, resulting in high packet loss-rate, and causing severe video quality degradation. To maintain the optimal video quali… 相似文献
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In order to improve the transmission accuracy and efficiency of sensing and actuating signals in Internet of Things(IoT) and ensure the system stability,an adaptive resource allocation algorithm is proposed,which dynamically assigns the network bandwidth and priority among components according to their signals’ frequency domain characteristics.A remote sensed and controlled unmanned ground vehicle(UGV) path tracking test-bed was developed and multiple UGV’s tracking error signals were measured in the simulation for performance evaluation.Results show that with the same network bandwidth constraints,the proposed algorithm can reduce the accumulated and maximum errors of UGV path tracking by over 60% compared with the conventional static algorithm. 相似文献
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由于光照变化、物体遮挡和复杂背景条件等众多因素的影响,目标检测一直是机器视觉领域最具有挑战性的问题。首先对视频目标检测算法中的孪生网络系列算法进行分析比较;然后将孪生网络与深度学习相结合,提出并构建全新的孪生网络跟踪器;最后将视频输入到设计好的孪生网络跟踪器中,通过网络对每一帧图像中物体的类别与位置进行准确地实时框选标注。分别将该算法和当前广泛应用的YOLOv3算法在OTB数据集上进行验证测试。测试数据表明:该算法的视频目标检测成功率和准确率均优于YOLOv3算法。 相似文献
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INTRODUCTION Video multicasting over wireless local area net- work (WLAN) (IEEE Standard 802.11, 1997) enables the distribution of live or pre-recorded programs to many receivers efficiently. An example application is to redistribute TV programs or location-specific in- formation in hot spots such as airport. Users can watch their favorite TV programs on mobile devices while browsing the Internet. For enterprise applica- tions, an example is multicasting video of a lecture or trainin… 相似文献
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INTRODUCTION Multimedia services over the Internet are be- coming popular due to the widespread deployment of broadband access. However, the conventional cli- ent-server architecture severely limits the number of simultaneous users, especially for bandwidth inten- sive applications such as video streaming. P2P net- works, on the other hand, offer a solution to the scalability problem. As a node joins a P2P network, it not only consumes resources but also contributes its bandwidth or comp… 相似文献
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INTRODUCTION With the development of novel wireless tech- nologies and increasing available bandwidth, multi- media applications over wireless networks become attractive for both businesses and end users. Fast de- ployment of Wi-Fi HotSpots, increase in wireless coverage of remote habitable areas (Wi-Max, or wireless mesh networks), improved data services over the 2G cellular systems and the long awaited debut of 3G wireless services offer many potential and inter- operable communicatio… 相似文献
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HTTP动态自适应流技术利用现有的内容分发网络和互联网基础设施,部署方便、快捷,具有良好的防火墙穿透能力、NAT转换功能,成为网络视频分发业务的主流技术。为保证媒体传输的流畅性,为用户提供良好的用户体验质量（QoE）,需要采用合理的码率选择算法,由此码率自适应选择算法成为研究热点,大量新方法不断涌现。对HTTP动态自适应流技术背景和概念进行了概述,从流媒体传输涉及的服务端和客户端两个决策实体出发,对大量方法进行了分类阐述,指出该领域存在的问题,对研究趋势进行了展望。 相似文献
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研究了多用户场景下多载波码分多址系统（MC—CDMA）的下行信道和功率分配,并将吞吐最大化问题建模成一个混合整数优化问题．为了简化分析,将问题分成2个低复杂度的子问题：功率分配和信道分配．这2个子问题可分别被一个次最优自适应功率分配算法（APA）和一个最优自适应信道分配算法（ACA）解决．通过联合APA和ACA算法,进一步提出了一个自适应信道和功率的分配方案．仿真结果表明：与传统的均匀功率分配算法相比,提出的APA算法更加适用于MC—CDMA系统;此外,提出的自适应信道和功率分配方案可以显著地提高系统吞吐量性能． 相似文献
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INTRODUCTION Streaming of multimedia data over the Internet has rapidly increased in recent years. All commercial applications and most research in video streaming use conventional hybrid video coding. To adapt the data transmission rate on the server to the varying bandwidth caused by congestion in the Internet or to different available bandwidths of different clients, the simulcast solution is widely applied (Balk et al., 2003; Feamster et al., 2001; Schierl and Wiegand, 2004). A larg… 相似文献
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给出对应于多元多重正交尺度函数的多重小波包的定义及其构造方法,讨论了多元多重不可分正交小波包的性质。 相似文献
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While the development of particular video segmentation algorithms has attracted considerable research interest, relatively little effort has been devoted to provide a methodology for evaluating their performance. In this paper, we propose a methodology to objectively evaluate video segmentation algorithm with ground-truth, which is based on computing the deviation of segmentation results from the reference segmentation. Four different metrics based on classification pixels, edges, relative foreground area and relative position respectively are combined to address the spatial accuracy. Temporal coherency is evaluated by utilizing the difference of spatial accuracy between successive frames. The experimental results show the feasibility of our approach. Moreover, it is computationally more efficient than previous methods. It can be applied to provide an offline ranking among different segmentation algorithms and to optimally set the parameters for a given algorithm. 相似文献
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While the development of particular video segmentation algorithms has attracted considerable research interest, relatively little effort has been devoted to provide a methodology for evaluating their performance.In this paper, we propose a methodology to objectively evaluate video segmentation algorithm with ground-truth, which is based on computing the deviation of segmentation results from the reference segmentation.Four different metrics based on classification pixels, edges, relative foreground area and relative position respectively are combined to address the spatial accuracy.Temporal coherency is evaluated by utilizing the difference of spatial accuracy between successive frames.The experimental results show the feasibility of our approach.Moreover, it is computationally more efficient than previous methods.It can be applied to provide an offline ranking among different segmentation algorithms and to optimally set the parameters for a given algorithm. 相似文献
19.
脉冲噪声的自适应滤除方法 总被引：1，自引：0，他引：1
武英 《南京晓庄学院学报》2005,21(5):25-27
为了在滤除图像噪声的同时更好的保护图像的细节,文中提出了一种基于非线性自适应滤波结构的改进算法。用中心加权中值滤波算法代替原方法中的中值滤波算法以及中值滤波代替均值滤波作为最终滤波结果输出。这种算法与同类算法相比,具有更好的滤波性能并能更好的保护细节,其效果明显优于中值滤波算法。 相似文献
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