一个基于内容的新闻视频浏览和查询系统:NewsBR

提出了一个基于内容的新闻视频浏览和查询系统NewsBR，这个系统是建立在非常准确的新闻故事分段和主题字幕文本提取之上的，它的主要特征包括：基于类别的新闻故事浏览，基于关键帧的视频摘要和基于关键词的新闻故事查询，本文详细讲述了新闻故事的分段，主题字幕文本的提取和在此之上的基于内容的视频浏览和查询，这个系统对于全面了解新闻视频的内容很有帮助且行之有效．     

新的基于综合特征的新闻事件分割方法

提出了一种基于新闻视频中的标题字幕信息和音视频特征对新闻事件进行分割的方法,并实现了一个新闻事件分割、浏览和检索的原型系统。提出的方法综合利用新闻视频中的标题检测、主持人画面检测以及静音片段和语者切换检测技术分割整段新闻中的新闻事件。实验结果表明,该方法较仅利用标题的新闻事件分割方法在分割准确性上有了显著提高。     

Feature set and architecture of a multimedia news system over an ATM network

In this paper we discuss a multimedia news system that we have developed in the Multimedia Information Research Laboratory at the University of Ottawa and beyond. We focus on the feature set—that is, the tools and facilities associated with the system. We explain the functionality of each and give some real examples of the system in action. We then outline the architecture—the system consists of a production server for document authoring, a conferencing system for collaborative news article creation, a content database for authors, a hypernews database for hypermedia news documents, a news database server with aging and archiving, and user sites. The goal was to have all components of the system communicating on OCRInet—an R&D ATM network in the Ottawa region. We then introduce the challenges of representing and browsing large video objects and to this end we introduce a novel solution that we call video-tiles. This video tool is an effective way to browse large news videos that are frequently connected with our multimedia news articles.     

Exploiting information extraction techniques for automatic semantic video indexing with an application to Turkish news videos

This paper targets at the problem of automatic semantic indexing of news videos by presenting a video annotation and retrieval system which is able to perform automatic semantic annotation of news video archives and provide access to the archives via these annotations. The presented system relies on the video texts as the information source and exploits several information extraction techniques on these texts to arrive at representative semantic information regarding the underlying videos. These techniques include named entity recognition, person entity extraction, coreference resolution, and semantic event extraction. Apart from the information extraction components, the proposed system also encompasses modules for news story segmentation, text extraction, and video retrieval along with a news video database to make it a full-fledged system to be employed in practical settings. The proposed system is a generic one employing a wide range of techniques to automate the semantic video indexing process and to bridge the semantic gap between what can be automatically extracted from videos and what people perceive as the video semantics. Based on the proposed system, a novel automatic semantic annotation and retrieval system is built for Turkish and evaluated on a broadcast news video collection, providing evidence for its feasibility and convenience for news videos with a satisfactory overall performance.     

Searching and editing MPEG-compressed video in a distributed online environment

WebClip (on-line demo at http://www.ctr.columbia.edu/webclip) is a compressed video searching and editing system operating over the World Wide Web. WebClip uses a distributed client-server model including a server engine for content analysis/editing, and clients for interactive controls of video browsing/editing. It specializes several unique features, including compressed-domain video feature extraction and manipulation, multi-resolution video access, content based video browsing/retrieval, and a distributed network architecture.     

On-line video abstract generation of multimedia news

The amount of video content available nowadays makes video abstraction techniques a necessary tool to ease the access to the already huge and ever growing video databases. Nevertheless, many of the existing video abstraction approaches have high computational requirements, complicating the integration and exploitation of current technologies in real environments. This paper presents a novel method for news bulletin abstraction which combines on-line story segmentation, on-line video skimming and layout composition techniques. The developed algorithm provides an efficient, automatic and on-line news abstraction method which takes advantage of the specific characteristics of news bulletins for obtaining representative news abstracts.     

Video placement and configuration of distributed video servers on cable TV networks

A large-scale, distributed video-on-demand (VOD) system allows geographically dispersed residential and business users to access video services, such as movies and other multimedia programs or documents on demand from video servers on a high-speed network. In this paper, we first demonstrate through analysis and simulation the need for a hierarchical architecture for the VOD distribution network.We then assume a hierarchical architecture, which fits the existing tree topology used in today's cable TV (CATV) hybrid fiber/coaxial (HFC) distribution networks. We develop a model for the video program placement, configuration, and performance evaluation of such systems. Our approach takes into account the user behavior, the fact that the user requests are transmitted over a shared channel before reaching the video server containing the requested program, the fact that the input/output (I/O) capacity of the video servers is the costlier resource, and finally the communication cost. In addition, our model employs batching of user requests at the video servers. We study the effect of batching on the performance of the video servers and on the quality of service (QoS) delivered to the user, and we contribute dynamic batching policies which improve server utilization, user QoS, and lower the servers' cost. The evaluation is based on an extensive analytical and simulation study.     

CEA: A Cyclic Expansion Algorithm for data migration in parallel video servers

Parallel video servers can achieve highly storage-saving and granularly load-balancing, but they suffer from a system expansion problem. As the number of users continuously increases, the system inevitably needs to expand the number of video servers. However, the expansion of a parallel video server system is not as simple as that of a replicated video server system. Hence, this work develops an efficient expansion algorithm, called the Cyclic Expansion Algorithm (CEA), for parallel video servers. The proposed CEA algorithm has several good features. First, the data layout of each video content exhibits periodicity. Consequently, the meta-data size of each video and the complexity of the CEA algorithm are reduced. Second, the number of required data movements during a system expansion is optimized. Third, the total number of required XOR recomputations for updating parity blocks during an expansion is also minimized. Additionally, the new CEA can be applied to a variety of distributed storage systems, such as the cloud-based storage systems using striping and parity check techniques.     

Odyssey: a high‐performance clustered video server

Video servers are essential in video‐on‐demand and other multimedia applications. In this paper, we present our high‐performance clustered CBR video server, Odyssey. Odyssey is a server connecting PCs with switched Ethernet. It provides efficient support for normal play and interactive browsing functions such as fast‐forward and fast‐backward. We designed a set of algorithms for scheduling, synchronization and admission control, which results in a high utilization of resources. Odyssey is able to deliver a large number of video streams. Copyright © 2003 John Wiley & Sons, Ltd.     

Performance analysis of a pull-based parallel video server

In conventional video-on-demand systems, video data are stored in a video server for delivery to multiple receivers over a communications network. The video server's hardware limits the maximum storage capacity as well as the maximum number of video sessions that can concurrently be delivered. Clearly, these limits will eventually be exceeded by the growing need for better video quality and larger user population. This paper studies a parallel video server architecture that exploits server parallelism to achieve incremental scalability. First, unlike data partition and replication, the architecture employs data striping at the server level to achieve fine-grain load balancing across multiple servers. Second, a client-pull service model is employed to eliminate the need for interserver synchronization. Third, an admission-scheduling algorithm is proposed to further control the instantaneous load at each server so that linear scalability can be achieved. This paper analyzes the performance of the architecture by deriving bounds for server service delay, client buffer requirement, prefetch delay, and scheduling delay. These performance metrics and design tradeoffs are further evaluated using numerical examples. Our results show that the proposed parallel video server architecture can be linearly scaled up to more concurrent users simply by adding more servers and redistributing the video data among the servers     

Proxy-assisted periodic broadcast for video streaming with multiple servers

Large scale video streaming over the Internet requires a large amount of resources such as server I/O bandwidth and network bandwidth. A number of video delivery techniques can be used to lower these requirements. Periodic broadcast by a central server combined with proxy caching offers a significant reduction of the aggregate network and server I/O bandwidth usage. However, the resources available to a single server are still limited. In this paper we propose a system with multiple geographically distributed servers. The problem of multiple servers for periodic broadcast is quite different from the problem of object location for multiple web servers. Multiple servers offer increased amount of resources and service availability and may potentially allow a further reduction of network bandwidth usage. On the other hand, the benefit of periodic broadcast mostly comes from high demand videos. With multiple servers holding a video, the demand of the video at each server is reduced. Therefore, it is a challenge to use multiple servers efficiently. We first analyze the dependence of the resource requirements on the number and locations of the servers. Based on the character of the function describing such a dependence, we formulate and solve the problem of video location and delivery, in a way that minimizes resource usage. We explore a trade-off between network and I/O bandwidth requirements. We evaluate our proposed solutions through a number of tests.

Design a progressive video caching policy for video proxy servers

Proxy servers have been used to cache web objects to alleviate the load of the web servers and to reduce network congestion on the Internet. In this paper, a central video server is connected to a proxy server via wide area networks (WANs) and the proxy server can reach many clients via local area networks (LANs). We assume a video can be either entirely or partially cached in the proxy to reduce WAN bandwidth consumption. Since the storage space and the sustained disk I/O bandwidth are limited resources in the proxy, how to efficiently utilize these resources to maximize the WAN bandwidth reduction is an important issue. We design a progressive video caching policy in which each video can be cached at several levels corresponding to cached data sizes and required WAN bandwidths. For a video, the proxy server determines to cache a smaller amount of data at a lower level or to gradually accumulate more data to reach a higher level. The proposed progressive caching policy allows the proxy to adjust caching amount for each video based on its resource condition and the user access pattern. We investigate the scenarios in which the access pattern is priorly known or unknown and the effectiveness of the caching policy is evaluated.     

Disk scheduling in video editing systems

Modern video servers support both video-on-demand and nonlinear editing applications. Video-on-demand servers enable the user to view video clips or movies from a video database, while nonlinear editing systems enable the user to manipulate the content of the video database. Applications such as video and news editing systems require that the underlying storage server be able to concurrently record live broadcast information, modify prerecorded data, and broadcast an authored presentation. A multimedia storage server that efficiently supports such a diverse group of activities constitutes the focus of this study. A novel real-time disk scheduling algorithm is presented that treats both read and write requests in a homogeneous manner in order to ensure that their deadlines are met. Due to real-time demands of movie viewing, read requests have to be fulfilled within certain deadlines; otherwise, they are considered lost. Since the data to be written into disk is stored in main memory buffers, write requests can be postponed until critical read requests are processed. However, write requests still have to be processed within reasonable delays and without the possibility of indefinite postponement. This is due to the physical constraint of the limited size of the main memory write buffers. The new algorithm schedules both read and write requests appropriately, to minimize the amount of disk reads that do not meet their presentation deadlines, and to avoid indefinite postponement and large buffer sizes in the case of disk writes. Simulation results demonstrate that the proposed algorithm offers low violations of read deadlines, reduces waiting time for lower priority disk requests, and improves the throughput of the storage server by enhancing the utilization of available disk bandwidth     

Staggered push - a linearly scalable architecture for push-based parallel video servers

With the rapid performance improvements in low-cost PCs, it becomes increasingly practical and cost-effective to implement large-scale video-on-demand (VoD) systems around parallel PC servers. This paper proposes a novel parallel video server architecture where video data are striped across an array of autonomous servers connected by an interconnection network. To coordinate data transmissions from multiple autonomous servers to a client station, a staggered push scheduling algorithm is proposed. A system model is constructed to quantify the performance of the architecture. Unlike most studies, this work does not assume the existence of a global clock among the servers and tackles two problems arising from server asynchrony: inconsistent schedule assignment and traffic overlapping. The former problem is solved by using an admission scheduler and the latter problem is solved by an over-rate transmission scheme. Analytical results prove a remarkable property of the staggered push architecture: as long as the network has sufficient capacity, the system can be scaled up linearly to an arbitrary number of servers. Design examples and numerical results are used to evaluate the proposed architecture under realistic assumptions and to compare it against other architecture.     

新闻视频结构化浏览与标注系统

阐述一种新颖的新闻视频结构化浏览和标注系统。应用基于时空切片分析的新闻主播检测方法和基于颜色直方图的镜头分割方法实现新闻视频的结构化。通过自动语音识别技术和特定语义概念模型的建立实现了对主播场景的文本信息标注和对新闻故事镜头的语义概念标注。该系统有利于用户根据个人爱好进行新闻视频的浏览和编辑,有效实现新闻视频的索引和浏览。     

Implementation of hybrid P2P networking distributed web crawler using AWS for smart work news big data

Web crawlers collect and index the vast amount of data available online to gather specific types of objective data such as news that researchers or practitioners need. As big data are increasingly used in a variety of fields and web data are exponentially growing each year, the importance of web crawlers is growing as well. Web servers that currently handle high traffic, such as portal news servers, have safeguards against security threats such as distributed denial-of-service (DDoS) attacks. In particular, the crawler, which causes a large amount of traffic to the Web server, has a very similar nature to DDoS attacks, so the crawler’s activities tend to be blocked from the web server. A peer-to-peer (P2P) crawler can be used to solve these problems. However, the limitations with the pure P2P crawler is that it is difficult to maintain the entire system when network traffic increases or errors occur. Therefore, in order to overcome these limitations, we would like to propose a hybrid P2P crawler that can collect web data using the cloud service platform provided by Amazon Web Services (AWS). The hybrid P2P networking distributed web crawler using AWS (HP2PNC-AWS) is applied to collecting news on Korea’s current smart work lifestyle from three portal sites. In Portal A where the target server does not block crawling, the HP2PNC-AWS is faster than the general web crawler (GWC) and slightly slower than the server/client distributed web crawler (SC-DWC), but it has a similar performance to the SC-DWC. However, in both Portal B and C where the target server blocks crawling, the HP2PNC-AWS performs better than other methods, with the collection rate and the number of data collected at the same time. It was also confirmed that the hybrid P2P networking system could work efficiently in web crawler architectures.

     

视频点播中视频服务器节目替换算法研究

提出了一种分布集群式的视频点播体系结构,针对视频点播系统特点设计了两种适用于系统不同的运行阶段的视频服务器节目替换算法。在视频点播系统初始化时间段内使用改进的LFRU算法进行节目替换;系统达到稳定状态后使用最小加权周期频率替换算法进行节目替换。对比实验表明两种替换算法适合分布集群式视频点播系统,其替换效率较高。