Deadline-aware network coding for video on demand service over P2P networks

We are interested in providing Video-on-Demand (VoD) streaming service to a large population of clients using peer-to-peer (P2P) approach. Given the asynchronous demands from multiple clients, continuously changing of the buffered contents, and the continuous video display requirement, how to collaborate with potential partners to get expected data for future content delivery are very important and challenging. In this paper, we develop a novel scheduling algorithm based on deadline- aware network coding (DNC) to fully exploit the network resource for efficient VoD service. DNC generalizes the existing net- work coding (NC) paradigm, an elegant solution for ubiquitous data distribution. Yet, with deadline awareness, DNC improves the network throughput and meanwhile avoid missing the play deadline in high probability, which is a major deficiency of the con- ventional NC. Extensive simulation results demonstrated that DNC achieves high streaming continuity even in tight network conditions.

THE APPLICATION RESEARCH OF VIDEO SERVER SYSTEM FOR VIDEO ON DEMAND

A comprehensive research on key issues of the large-scale video server system for Video On Demand (VOD) client/server system is conducted based mainly on real time (rt)/non-real time (nrt) Variable Bit Rate or Constant Bit Rate (VBR/CBR) MPEG-2 MP@ML Signal Program Transport Stream (SPTS) for movies, and general architecture for storage, control, caching subsystems from Loosely Coupled Computer (LCC), Symmetric Multiple Processing (SMP), and Massively Parallel Processing (MPP) video server is conceptualized. Meanwhile, Redundant Array of Inexpensive Disks (RAID) storage system are presented and the centralized FCP/SAN huge storage technology is introduced in terms of its scalability, throughput, and connectivity performances.

MULTI-EPIPOLAR LINES MATCHING-BASED RAY-SPACE INTERPOLATION FOR FREE VIEWPOINT VIDEO SYSTEM

Ray-space based arbitrary viewpoint rendering without complex object segmentation or model construction is the main technology to realize Free Viewpoint Video(FVV) system for complex scenes. Ray-space interpolation and compression are two key techniques for the solution. In this paper,correlation among multiple epipolar lines in ray-space data is analyzed,and a new method of ray-space interpolation with multi-epipolar lines matching is proposed. Comparing with the pixel-based matching interpolation method and the block-based matching interpolation method,the proposed method can achieve higher Peak Signal to Noise Ratio(PSNR) in interpolating rayspace data and rendering arbitrary viewpoint images.

Research on Video on Demand Based on P2P Network

A P2P approaches to extend the ability of Video on Demand systems to serve more users. In the proposed system users share with each other the media data obtained and the media server is no longer the only source to get data from, thereby, the load on the media server could be greatly alleviated and the overall system capacity increases and more users could be served. The P2P streaming system introduces efficient searching;data transfer dynamically monitoring and initial buffering to maintain a high quality of playback. Its provider selection policy helps to reduce the load of the underlying network by avoiding remote data transfer.

Efficient video-on-demand services over mobile datacast channels

The integration of reliable Video-on-Demand (VoD) broadcasting schemes in the DVB-h transmission system is studied, exemplary for Pyramid Broadcasting (PB). Sophisticated VoD broadcasting schemes such as PB allow receivers to tune into the ongoing transmission of a video-stream at arbitrary time, while still being able to receive the multimedia sequence from the beginning to end, after a short initial playout latency. Raptor coding, integrated in the FLUTE protocol, is combined with the traditional PB scheme in order to provide high service and presentation reliability. We give a short overview on the DVB-h transmission system as well as on the FLUTE protocol. We present and discuss options for the integration of VoD broadcasting schemes in combination with Raptor coding. We achieve backward-compatibility even with terminals not supporting Raptor coding. Simulation results show the benefits of the discussed VoD scheme compared to existing carousel approaches in DVB-h.

An Adaptive Video-on-Demand Framework for Multimedia Cross-Platform Cloud Services

Although Video-On-Demand (VOD) has been in existence for years, its cross-platform applicability in cloud service environments is still in increasing need. In this paper, an Adaptive Video-On-Demand (AVOD) framework that is suitable for private cloud environments is proposed. Private cloud has the key advantage of satisfying the real need of both consumers and providers. Hence, demands such as reasonable benefits for provider and high quality for consumers are essential design considerations in this framework. The difficulty is that these two factors are always high in one end and low in the other, and hard to find a delicate balance. Cloud service could be an opportunity for the multimedia providers to obtain higher benefits and cost less for the consumers but with an even better quality in service. An adaptive framework for such a cloud service environment is proposed to resolve this problem. Some interesting phenomena are observed from the experimental results including CPU utilization, data reading and writing speed, memory usage, port configuration execution time, and bandwidth.

Investigating the Effects of the Driving Cycle and Penetration of Electric Vehicles on Technical and Environmental Characteristics of the Hybrid Energy System Considering Uncertainties

Electric vehicles(EVs)have received special consideration from modern society over the past several years.Although EVs are a fine example of environmentally friendly technology and have many advantages,they relatively increase the electricity demand upon a power grid as well.Therefore,their negative impact on busvoltage and line losses should be analyzed.In this study,the effect of EV loads and their penetration on bus voltage and line losses of an IEEE-33 bussystem has been examined via two scenarios.It is important to mention that the effect of EVs on the rate of air pollution,produced by fossil fuel electricity generators,has been investigated throughout the study.Also,the key role of demand response programs in the reduction of EVs’negative effects on the grid has also been discussed in the last scenario.Generally,the simulation of this paper provides a novel and wider perspective on EVs and their effect on grids and environmental pollution.

Smart Home Networking: Lessons from Combining Wireless and Powerline Networking

Integrating the power grid technology with renewable power generation technologies, Demand Response (DR) programs enabled by the Advanced Metering Infrastructure (AMI) were introduced into the power grid in the interest of both utilities and residents. They help to achieve load balance and increase the grid reliability by encouraging residents to reduce their power usage during peak load periods in return for incentives. To automate this process, appliances, in-house sensors, and the AMI controller need to be networked together. In this paper, we compare mainstream network technologies applicable to home appliance control and propose a solution combining Power Line Communication (PLC) with wireless communication in smart homes for the purpose of energy saving. We extended NS-2, a popular network simulator, to model such combined network scenarios. Using a number of different routing strategies, we then model and evaluate the network performance of DR programs in smart homes in such a combined network.

基于Jetson-TX2的输电线路设备实时巡检系统

针对输电线路及设备巡检效率低的问题,设计了一种基于Jetson-TX2的输电线路设备实时巡检系统。该系统包括基于YOLO v3算法的Jetson-TX2主控模块和云台相机控制模块。Jetson-TX2主控模块通过TensorRT加速库,对YOLO v3算法模型进行优化加速,完成视频流目标实时识别与定位;采用PID算法控制云台(PTZ)相机,实现设备的高清图像采集。该系统对输电线路设备整体识别准确率达95%,可实现对视频流的实时检测,有效提高输电线路巡检效率。

基于GPON的多业务承载系统研究

随着IPTV、手机电视等IP以太网基础上的多业务的需求越来越大,电信运营商面临各自的接入网在"三网融合"形势下的新挑战和新机遇。目前的基于铜缆宽带接入网虽然能够提供基于互联网的视频,但距离真正大规模三网融合业务的运营仍存在较大差距。通过对GPON光网络架构分析,给出了多业务承载网络的QoS功能的实现,并实现端到端QoS质量的保证,通过测试验证了方案的可行性,最后针对国内某省电信运营商GPON试点局建网分析和研究,探索出一套满足电信运营商的三网融合方案。

基于WPON和SIP协议的高清视频智能平台应用

在220kV5,00kV变电站构建一个控制、交换基于SIP协议、通道基于WPON无源光网络、图像格式达到D4(1280×720)的高清智能视频监控平台,实现全网模式统一的、多级管理的、图像资源共享的高清视频监控构架体系。研制协议网关,将原有不同格式的标清视频图像转换成统一H.264格式,通过SIP软交换协议,实现标清和高清图像无缝接入至平台系统,从而解决了现有变电站视频监控系统传输速率低、接口协议不兼容、视频图像质量低等问题;同时,对变电站出线及设备覆冰、线路舞动以及气象监测等所采集的数据连同高清视频图像通过先进的WPON技术回传至平台进行智能分析处理,为电网生产运行、应急保障提供辅助决策作用。

Parameters for Use of BEWAB＋ Programme to Schedule Irrigation of Pea （Pisum sativum L,）

A large portion of irrigation farmers make use of subjective （intuition） irrigation scheduling methods as supposed to objective or scientific irrigation scheduling methods, which need to be changed. The BEsproeiingsWAterbestuursprogram （BEWAB＋） irrigation scheduling programme is based on the water balance equation and needs： （1） a crop production function; （2） a relative consumptive water demand curve and （3） an allowable depletion subroutine. The objective of this paper was to describe research aimed at obtaining information on （1） and （2） for pea and also to describe the effect of water application on yield and water use of pea. BEWAB＋ uses this information to estimate the daily irrigation water requirements for a particular soil-crop-atmosphere system under irrigation. A field experiment, based on published line-source irrigation methodology, was conducted on a 3 m deep loamy fine sand Bainsvlei or Ustic Quartzipsamment soil near Bloemfontein （26°08′S; 29°01′E） in South Africa. Results showed that there is a linear relationship of the form Ys = 8.07ET - 249 （r2 = 0.91）, where Ys is the seed yield of pea （kg/ha） and ET is evapotranspiration for the growing season （mm）. The relative consumptive water demand curve is represented by the following third order polynomial function that describes the relationship between time and relative ET for a pea growing season of 120 days： ETrelx = 0.09419646 - 0.01302413x ＋ 0.00059008x2 - 0.00000371x3. ETrelz denotes relative ET and x denotes time in days. A workable balance between practical problem solving and advanced irrigation science has been established with BEWAB＋. Pre-plant irrigation schedules can be made for semi-arid areas with the BEWAB＋ programme using easily obtainable inputs, like target yield, soil depth and soil particle size distribution information.

Brand Narration and Fashion Films

Starting from the new approaches of brand communication in New Millennium Era, we show why, according to us,the fashion film is a powerful tool in defining and strengthening the visual identity of a fashion brand. Our analysisis focused on ordering the different kinds of narration in this special category of orl-line videos and we discover thatthey work about the three fundamental parameters of the Visual Identity Model.

基于I-PON数据引导技术的视频分发系统

超高清视频4K正逐步走向民用,而未来的8K和新兴的VR视频将需要更大的带宽,用户观看视频方式需要更多可选择的方式,如IPTV、手机视频、互联网电视等。传统的有线电视网技术所提供的带宽容量捉襟见底,无法满足人们的需求。如何将高性能、低成本的传统有线电视网络平稳地转变为一张适合于未来发展需求的电视网络是一个重要的课题。针对传统有线电视网络中存在的弊端,提出一种基于I-PON数据引导技术的视频分发系统,该系统采用I-PON作为光纤入户系统技术规范,通过服务器模拟终端用户向上申请节目源,进行数据引导,最后利用SDN交换机特有的流表转发规则及终端设备可识别机制,实现点播和推流控制。该系统所采用的设备经济实惠,同时大大提升了整套系统的性能,具有较强的稳定性,对于传统网络可以进行平滑过渡,大幅度减少了运营商的建设和维护成本,满足用户高质量体验的需求。

Highly Available Hypercube Tokenized Sequential Matrix Partitioned Data Sharing in Large P2P Networks

Peer-to-peer (P2P) networking is a distributed architecture that partitions tasks or data between peer nodes. In this paper, an efficient Hypercube Sequential Matrix Partition (HS-MP) for efficient data sharing in P2P Networks using tokenizer method is proposed to resolve the problems of the larger P2P networks. The availability of data is first measured by the tokenizer using Dynamic Hypercube Organization. By applying Dynamic Hypercube Organization, that efficiently coordinates and assists the peers in P2P network ensuring data availability at many locations. Each data in peer is then assigned with valid ID by the tokenizer using Sequential Self-Organizing (SSO) ID generation model. This ensures data sharing with other nodes in large P2P network at minimum time interval which is obtained through proximity of data availability. To validate the framework HS-MP, the performance is evaluated using traffic traces collected from data sharing applications. Simulations conducting using Network simulator-2 show that the proposed framework outperforms the conventional streaming models. The performance of the proposed system is analyzed using energy consumption, average latency and average data availability rate with respect to the number of peer nodes, data size, amount of data shared and execution time. The proposed method reduces the energy consumption 43.35% to transpose traffic, 35.29% to bitrev traffic and 25% to bitcomp traffic patterns.

基层选择性应付民众诉求的发生机理及其治理策略

基层是观察中国治理实践、理解中国行政体制的重要窗口。特别是在“人民至上”的新时代,基层是实现“民有所呼,我有所应”的基础环节。已有研究多关注基层工作者在政策执行过程中的应付行为,鲜有其“问题解决者”角色的相关研究。依据政治系统理论,并结合研究事实的发展过程,可以从联系阶段的程序依赖、转换阶段的策略空转、输出阶段的避责建议三个方面,对基层工作者的选择性应付进行类型化分析。研究发现,复合交织的立体化系统环境、复杂性转向的情境化诉求与诉求转换处理的系统限制性三重因素相互叠加,共同影响并导致了选择性应付行为的发生。要解决这一问题需优化基层工作的系统环境、探索建立解决民众诉求的分级分类管理体系、建立职业能力培养的长效发展机制。

CPA-VoD： Cloud and Peer-Assisted Video on Demand System for Mobile Devices

With the rapid development of WiFi and 3G/4G, people tend to view videos on mobile devices. These devices are ubiquitous but have small memory to cache videos. As a result, in contrast to traditional computers, these devices aggravate the network pressure of content providers. Previous studies use CDN to solve this problem. But its static leasing mechanism in which the rental space cannot be dynamically adjusted makes the operational cost soar and incompatible with the dynamically video delivery. In our study, based on a thorough analysis of user behavior from Tencent Video, a popular Chinese on-line video share platform, we identify two key user behaviors. Firstly, lots of users in the same region tend to watch the same video. Secondly, the popularity distribution of videos conforms with the Pareto principle, i.e., the top 20% popular videos own 80% of all video traffic. To turn these observations into silver bullet, we propose and implement a novel cloud- and peer-assisted video on demand system （CPA-VoD）. In the system, we group users in the same region as a peer swarm, and in the same peer swarm, users can provide videos to other users by sharing their cached videos. Besides, we cache the 10% most popular videos in cloud servers to further alleviate the network pressure. We choose cloud servers to cache videos because the rental space can be dynamically adjusted. According to the evaluation on a real dataset from Tencent Video, CPA-VoD alleviates the network pressure and the operation cost excellently, while only 20.9% traffic is serviced by the content provider.

我国城市轨道交通既有线改造路径探讨

随着城镇化进程的加快,城市轨道交通既有线改造在促进城轨高质量发展和城市可持续发展方面具有重要的战略意义。既有线改造涉及专业面广、待解决问题复杂,过去以解决安全问题为主要目标的消隐改造、以部分专业为对象的专项改造已难以满足新时代既有线改造需求。因此,面对城市轨道交通高质量发展要求,亟须深入探讨我国城市轨道交通既有线改造发展路径。本文在梳理北京既有线改造历程的基础上,从面临的问题与实现的愿景两方面展开了对城市轨道交通既有线改造需求的分析,提出了既有线改造的整体思路,同时从城轨可持续发展方面创新地提出了既有线改造中的投融资思路,并从制度建设、要素活力、投融资机制、科技赋能、技术攻关、相关标准6个方面给出既有线改造工作建议,以期为我国城市轨道交通既有线改造提供思路。