Distributed QoS-aware source-specific multicast routing protocol

1 Introduction 1 Multiparty applications based on group communication such as video conference, remote education and so on are expected to become widespread in the Internet in the future. Now, the network transmission mode is unicast with a single receiver. If there are multiple receivers, the sender has to transmit multiple copies of the same data. Obviously, the unicast is inefficient for increasing one-to-many and many-to-many network applications. Multicast (RFC1112) is one of the effect…     

Sports video summarization and adaptation for application in mobile communication

Sports video appeals to large audiences due to its high commercial potentials. Automatically extracting useful semantic information and generating highlight summary from sports video to facilitate users‘ accessing requirements is an important problem, especially in the forthcoming broadband mobile communication and the need for users to access their multimedia information of interest from anywhere at anytime with their most convenient digital equipments. In this paper, a system to generate highlight summaries oriented for mobile applications is introduced, which includes highlight extraction and video adaptation. In this system, several highlight extraction techniques are provided for field sports video and racket sports video by using multi-modal information. To enhance users‘ viewing experience and save bandwidth, 3D animation from highlight segment is also generated. As an important procedure to make video analysis results universally applicable, video transcoding techniques are applied to adapt the video for mobile communication environment and user preference. Experimental results are encouraging and show the advantage and feasibility of the system for multimedia content personalization, enhancement and adaptation to meet different user preference and network/device requirements.     

An optimal quality adaptation mechanism for end-to-end FGS video transmission

In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS) stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quality variation and increasing available bandwidth usage rate. Under the condition that the whole bandwidth evolution is known, we design an optimal algorithm to select layer. When the knowledge of future bandwidth is not available, we also develop an online algorithm based on the optimal algorithm. Simulation showed that both optimal algorithm and online algorithm can offer smoothed video quality evolution.     

An efficient training sequences strategy for channel estimation in OFDM systems with transmit diversity

INTRODUCTION Orthogonal frequency division multiplexing (OFDM) is now a popular technique for high data rate wireless communication. Due to its simple imple-mentation and attractive performance against fre-quency-selective wireless fading channels, it has been adopted in several wireless standards such as digital audio broadcasting (DAB), digital video broadcasting (DVB), IEEE 802.11a local area network (LAN), IEEE 802.16a metropolitan area network (MAN) and asymmetric digital s…     

A network condition classification scheme for supporting video delivery over wireless Internet*

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…     

以太无源光网络接入控制器的实现

1IntroductionWith the developing of packet switching and trans-mission technologies,many IP-oriented applicationshave experienced a substantial growth,makingit pos-sible for various real-ti me broadband video servicesviathe Internet.However,current access networktechnologies can only offer512k-2M subscriberbandwidth,whichis unable to meet the broadband de-mand of emerging3Tnet services such as high-defini-tion video(HDTV)and real-ti me network TV broad-cast.Therefore,the access network sti…     

无线移动数字图书馆系统中多媒体检索的同步模式

1IntroductionRecent advances in wireless communication,digitallibrary,distributed multi media,massive storage,andmobile computing technologies are sti mulating the de-velopment of mobile multi media digital library systems(M2DLS)that allow mobile clients to access multi me-dia material anywhere and anyti me over a cellular ra-dio network[1,2].In M2DLS,multi media objects,ingeneral,can be composed of multiple media streamssuch as audio and video,whose retrieval must proceedso as to not only …     

Channel adaptive rate control for energy optimization

Low energy consumption is one of the main challenges for wireless video transmission on battery limited devices. The energy invested at the lower layers of the protocol stack involved in data communication, such as link and physical layer, represent an important part of the total energy consumption. This communication energy highly depends on the channel conditions and on the transmission data rate. Traditionally, video coding is unaware of varying channel conditions. In this paper, we propose a cross-layer approach in which the rate control mechanism of the video codec becomes channel-aware and steers the instantaneous output rate according to the channel conditions to reduce the communication energy. Our results show that energy savings of up to 30% can be obtained with a reduction of barely 0.1 dB on the average video quality. The impact of feedback delays is shown to be small. In addition, this adaptive mechanism has low complexity, which makes it suitable for real-time applications.     

Frame loss error concealment for SVC

INTRODUCTION Real-time transmission of video data in network environments, such as wireless and Internet, is a challenging task, as it requires coding efficiency, network friendliness and error robustness. Scalability is a possible solution for network adaptive applica- tions. The Scalable Extension of H.264/AVC (SVC) (JVT of ISO/IEC MPEG & ITU-T VCEG, 2005b) aims at achieving both high compression performance and adaptivity for video delivery over heterogeneous networks. SVC…     

Multiple description scalable video coding based on 3D lifted wavelet transform

INTRODUCTION With the expansion of multimedia applications, video transmission is becoming an important issue in the research area of communication. It is very im- portant to compress a large amount of video data effectively, which has already attracted considerable attention recently. To make source coders both er- ror-resilient and network-adaptive are two main challenges facing the video compression techniques. It is necessary to make the bitstreams temporal, spa- tial and SNR scalabl…     

A complexity-scalable software-based MPEG-2 video encoder

With the development of general-purpose processors (GPP) and video signal processing algorithms, it is possible to implement a software-based real-time video encoder on GPP, and its low cost and easy upgrade attract developers' interests to transfer video encoding from specialized hardware to more flexible software. In this paper, the encoding structure is set up first to support complexity scalability; then a lot of high performance algorithms are used on the key time-consuming modules in coding process; finally, at programming level, processor characteristics are considered to improve data access efficiency and processing parallelism. Other programming methods such as lookup table are adopted to reduce the computational complexity. Simulation results showed that these ideas could not only improve the global performance of video coding, but also provide great flexibility in complexity regulation.     

Very Low Bit Rate Video Coding Using Motion Compensated 3 D Wavelet TransformVery Low Bit Rate Video Coding Using Motion Compensated 3 D Wavelet Transform

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Ethically scaling up interventions in educational development: a case for collaborative multi-sited ethnographic research

Educational interventions are often administered at scale in diverse settings as part of international development programmes. Their implementation is subject to a linear process that begins with finding out ‘what works’ at a local level, frequently through the use of randomised controlled trials, and continues with rolling out the intervention to the whole population at a national or even transnational level. This process often fails to consider the role cultural, political, and historical factors play in the perceived success of the local intervention, which can compromise both the impact and the ethics of at-scale implementation. To help address this issue, this paper argues for a definition of scalability that incorporates the ethics of the practice of scaling. It points to the potential of collaborative multi-sited ethnographic research to identify nuanced understandings of the different ethics systems endogenous to individual sites of implementation, in lieu of the universalising notions of ethics that are embedded in mainstream, linear notions of scalability. In so doing, it makes the case for multi-sited critical ethnography as a methodology of choice in researching the scalability of interventions in the context of development projects in the ‘Global South’.     

决策树分类算法的可扩展性研究

决策树是数据挖掘分类问题算法中一种性能较好的算法,本文主要研究自决策树在数据挖掘中应用以来存在问题,主要是可扩展性问题.综述了国内外针对此问题所提出的解决方法,以及分析了改进算法的优缺点,以便有利于对决策树关键问题,即扩展性问题的研究.同时本论文中所研究的算法的思想也有助于数据挖掘中其它领域解决大数据集问题.     

新型云计算数据中心网络结构设计

随着云计算和大数据应用的飞速发展,对传统的数据中心网络提出了新的挑战。本文设计一种新型的以服务器为中心的层次递归云计算数据中心网络结构GCube,该网络可以采用通用服务器和普通商用交换机进行构建,具有极高的性价比、优秀的性能和可扩展性。     

More efficient ground truth ROI image coding technique： implementation and wavelet based application analysis

In this paper, more efficient, low-complexity and reliable region of interest (ROI) image codec for compressing smooth low texture remote sensing images is proposed. We explore the efficiency of the modified ROI codec with respect to the selected set of convenient wavelet filters, which is a novel method. Such ROI coding experiment analysis representing low bit rate lossy to high quality lossless reconstruction with timing analysis is useful for improving remote sensing ground truth sur- veillance efficiency in terms of time and quality. The subjective [i.e. fair, five observer (HVS) evaluations using enhanced 3D picture view Hyper memory display technology] and the objective results revealed that for faster ground truth ROI coding applications, the Symlet-4 adaptation performs better than Biorthogonal 4.4 and Biorthogonal 6.8. However, the discrete Meyer wavelet adaptation is the best solution for delayed ROI image reconstructions.     

Very low bit-rate video coding based on wavelet transform

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海量存储系统中高扩展性元数据分布算法的研究

Distribution of metadata in a metadata server cluster is important in mass storage system. A good distribution algorithm has a significant influence on the system performance, availability and scalability. Subtree partition and hash are two traditional metadata distribution algorithms used in distributed file systems. They both have a defect in system scalability. This paper proposes a new directory hash （DH） algorithm. By treating directory as the key value of hash function, implementing concentrated storage of metadata, pipelining operations and prefetching technology, DH algorithm can enhance the system scalability on the premise without sacrificing system performance.