检索结果-内蒙古大学图书馆

IEEE Annual International Computer Software and Applications Conference (COMPSAC)

作者： W.Y. Lum F.C.M. Lau Department of Computer Science & Information Systems University of Hong Kong Hong Kong China

We propose a decision engine with QoS awareness that can automatically negotiate for the appropriate adaptation strategies to be used to produce an optimal adapted version. The QoS-sensitive approach complements the lossy nature of the transcoding operations. The decision engine will look for the best tradeoff among various parameters in order to reduce the loss of quality, in various domains. Quantitative methods are suggested to measure the QoS of the content versions. Based on the particular user perception of these quality domains and other context information on the client capability, the proposed negotiation algorithm will determine a content version with a good aggregate score. We study factors such as processing overhead and the optimization accuracy of the algorithm, and their tradeoff. We built a prototype document adaptation system for PDF documents to demonstrate the viability of our approach.

关键词： Mobile computing Context Search engines transcoding Context-aware services Internet Computer science Information systems Aggregates Prototypes

来源：评论

学校读者我要写书评

暂无评论

QoS control of multimedia communication over wireless network

QoS control of multimedia communication over wireless networ...

引用

International Conference on Distributed Computing Systems Workshop

作者： K. Takahata N. Uchida Y. Shibata Faculty of Software and Information science Iwate Prefectural University Iwate Japan

In this paper QoS control of a real-time multimedia communication system under heterogeneous environments of wired and wireless networks is proposed. In our suggested system, as channel coding the FEC (forward error correction) method with Reed-Solomon coding is introduced to reduce the packet error rate on the wireless network. On the other hand, as source coding, transcoding methods including transformation of various video codings such as M-JPEG, MPEG and Quicktime, control of Q-factor within a frame, frame rate and color depth are introduced to maintain the required QoS, particularly the end-to-end throughput. The increases of the required bandwidth by redundant packet addition with FEC can be suppressed by the transcoding functions while the packet error rate is reduced to the accepted value. In order to verify the functionality and the efficiency in our suggested system, numerical simulation was carried out. As a result, our suggested system by combination of transcoding and FEC could correct the packet error rate with an order of 10/sup 9/ while maintaining the frame rate and the amount of data transform constant.

关键词： Communication system control Multimedia communication Wireless networks Forward error correction Error analysis transcoding Control systems Real time systems Multimedia systems Channel coding

来源：评论

学校读者我要写书评

暂无评论

An analysis of architecture of videoconferencing system based on concept of active network

An analysis of architecture of videoconferencing system base...

引用

European Conference on Universal Multiservice Networks (ECUMN)

作者： R.R. Chodorek Department of Telecommunications University of Mining and Metallurgy Poland

Guaranteed QoS transmission can be performed using signalling reservation protocols, as RSVP. In some situations, if (due to limited network resources) reservation is difficult or impossible, a change of transmitted traffic parameters will be necessary. The RTP protocol recommendation permits translation mechanisms to change transmitted stream parameters on the local network boundary. RTP transcoders adaptively change parameters of the stream based on current network state and end-user requirements. In the paper the architecture of videoconferencing systems with integrated end-to-end QoS management is presented. The proposed QoS management is based on distributed measurements carried out by mobile agents and consists of, between others, a set of transcoding agents located in the network nodes.

关键词： Teleconferencing Streaming media Mobile agents transcoding Multimedia systems Videoconference Control systems Bandwidth Protocols Error analysis

来源：评论

学校读者我要写书评

暂无评论

NTUs: an intelligent tutorial system fosters number concepts through computational scaffolding

NTUs: an intelligent tutorial system fosters number concepts...

引用

International Conference on Computers in Education

作者： Chih-Wei Hue Chien-Huei Kao Ming Lo Chien-Chih Chiang Liong-Yu Tu Wen-Lian Hsu Department of Psychology National Taiwan University Taiwan Institute of Computer Science Academia Sinica Taiwan

ISBN: (纸本)0769515096

The present article describes how scaffolding is implemented in an intelligent tutorial system call NTUs (number transcoding tutorial system), and what are the results of the system tested empirically on a group of grade students in fostering their number concepts. To use NTUs the system first analyzes a user's errors on a number transcoding task, and the results of analysis are used to infer the user's zone of proximal development (ZPD). A scaffolding process which vas designed with inspiration from how people learn Chinese calligraphy is provided next in the user's ZPD. An empirical test indicates that NTUs can not only foster students' number concepts, but can also attract them to use it.

关键词： Tutorial Intelligent systems Computational intelligence transcoding System testing Buildings Psychology Computer science Error analysis Process design

来源：评论

学校读者我要写书评

暂无评论

A dynamic video combiner for multipoint video conferencing using wavelet transform

A dynamic video combiner for multipoint video conferencing u...

引用

IEEE International Conference on Multimedia and Expo (ICME)

作者： Kai-Tat Fung Wan-Chi Siu Ngai-Fong Law Centre for Multimedia Signal Processing Department of Electronic and Information Engineering Hong Kong Polytechnic University Kowloon Hong Kong China

A new architecture of video combiner for multipoint video conferencing is proposed. The proposed video combiner is wavelet-based which extracts the motion activities information from the video bitstreams produced by a wavelet-based video coder. Using the progressive properties of wavelet transform, the encoded bitstream become scalable. Hence, the video quality of inactive sub-sequences can be easily adjusted in the video combiner by discarding the fine detail information bitstreams. In other words, more bits can be reallocated to the active sub-sequences to achieve a good visual quality with smooth motion. In addition, the video coder is region-based so that different wavelet kernels can be used for the foreground and the background. This setting can on one hand reduce the computational complexity significantly. On the other hand, by considering the unequal importance of various regions, a high video quality in foreground can always be guaranteed and an acceptable quality in background can be maintained even under low bitrate environments. Since the video combiner only needs to rearrange the video quality level according to their motion activities, no re-encoding process is required. Therefore, a significant computational complexity saving can be achieved as compared to the conventional video combiner using a transcoding approach. The new video combiner is then used to realize a multipoint video conferencing and some results are presented to show the improvement in performance due to our proposed architecture.

关键词： Videoconference Wavelet transforms Video compression transcoding Computational complexity Bandwidth Decoding Bit rate Switches ISDN

来源：评论

学校读者我要写书评

暂无评论

mc-SPF: an application-level multicast service path finding protocol for multimedia applications

mc-SPF: an application-level multicast service path finding ...

引用

IEEE International Conference on Multimedia and Expo (ICME)

作者： Jingwen Jin M. Nahrstedt Department of Computer Science University of Illinois Urbana-Champaign USA

Much of the current multimedia application deployment relies on composable service systems, where complex multimedia services are composed dynamically from multiple simpler ones that may be widely distributed. Related to such a scenario is the problem of finding feasible service paths that meet end-to-end requirements. Research has been done in discovering individual (unicast) service paths. In this paper, we apply multicast at the application layer, and develop a multicast service routing protocol that builds service trees whose individual paths satisfy end-to-end service requirements. Our ns-2 simulation results show that, compared to unicast, multicast can save up to 40% in communication cost, 43% in resource usage, yet incur less message overhead.

关键词： Multicast protocols Costs Application software Multimedia systems Unicast Routing protocols transcoding Bandwidth Computer science Protection

来源：评论

学校读者我要写书评

暂无评论

Personalized multimedia services using a mobile service platform

Personalized multimedia services using a mobile service plat...

引用

IEEE Conference on Wireless Communications and Networking

作者： Yih-Farn Chen Huale Huang R. Jana S. John S. Jora A. Reibman Bin Wei AT and T Research Laboratories Florham Park NJ USA

ISBN: (纸本)0780373766

In this paper we address the research issues in providing personalized multimedia services, which enable a mobile user to remotely record video programs, control cameras, and request the delivery of pre-recorded or live video content to his or her own mobile device. We describe a mobile service platform that authenticates users who send service requests from various mobile devices, transcodes video content based on user and device profiles, and authorizes the delivery of content from a media server to the proper client device. The media server adapts automatically to the fluctuations of the wireless channel conditions for reasonable viewing on the client device. The mobile service platform essentially manages the control path, while the media server handles the actual content delivery. We discuss various aspects of the integration and report our successful experiments conducted on wireless LAN and CDPD networks.

关键词： transcoding Wireless LAN Cameras Switches Fluctuations Internet Web sites Personal communication networks Portable computers IP networks

来源：评论

学校读者我要写书评

暂无评论

MPEG-2 video transmission using the HIPERLAN/2 WLAN standard

引用

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2001年第3期47卷 354-363页

作者： Doufexi, A Redmill, D Bull, D Nix, A Univ Bristol Ctr Commun Res Bristol BS8 1UB Avon England

At present, Wireless Local Area Networks (WLANs) supporting broadband multimedia communication are being developed and standardized around the world in the 5GHz band. Systems such as IEEE802.11a and HIPERLAN/2 will provide data rates up to 54 Mbps. Highly compressed data such as video are extremely sensitive to the errors that are commonly encountered in wireless channels. This paper addresses the problems of transmitting MPEG-2 video over WLANs, and in particular HIPERLAN/2. Error resilient video transcoding is proposed as a means of handling channel errors.

关键词： Wireless LAN Automatic repeat request Streaming media Multimedia communication Video compression Throughput Multimedia systems Wireless sensor networks transcoding Telecommunication standards

来源：评论

学校读者我要写书评

暂无评论

Wireless gateway for wireless home AV network and its implementation

引用

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2001年第3期47卷 496-501页

作者： Saito, T Tomoda, I Takabatake, Y Teramoto, K Fujimoto, K Toshiba Co Ltd Ctr Corp Res & Dev Kanagawa Japan

In this paper, we propose a wireless gateway for a wireless home AV network. We show the requirements the wireless gateway must satisfy in order to make practice the realization of wireless AV equipment and interconnectivity between wired (IEEE1394) and wireless networks and compare possible architectures. Then, we propose a "gateway" approach, which realizes both simple implementation and legacy device support. We show our implementation of the wireless gateway, which transmits AV control commands and high-quality AV data, and supports auto-configuration capability. It also has a real-time transcoding function which transcodes DV data on IEEE1394 into MPEG2 video on a wireless network.

关键词： home network wireless network wireless gateway IEEE1394 802.11 transcoding

来源：评论

学校读者我要写书评

暂无评论

Universal multimedia access from wired and wireless systems

引用

CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2001年第3-4期20卷 387-402页

作者： Perkis, A Abdeljaoued, Y Christopoulos, C Ebrahimi, T Chicharo, JF Norwegian Univ Sci & Technol Dept Telecommun N-7491 Trondheim Norway Swiss Fed Inst Technol EPFL Signal Proc Lab CH-1015 Lausanne Switzerland Ericsson Radio Syst AB Ericsson Res Corp Unit MediaLab S-16480 Stockholm Sweden Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2500 Australia

Personal computing and communication devices such as computers, personal digital assistants (PDAs), and mobile phones are moving to their next generation in which the end user will be able to access a multitude of information with a single device either locally or through a network. One likely trend in future personal computing and personal communication is that there will not be a single but several equivalent devices available to users allowing access to information in various forms. Each user, depending on his/her needs would access one or several among them depending on the situation and his/her preference. Using existing protocol mechanisms, in this case, a mapping and negotiation of resources during connection setup would be performed, which would remain in place throughout the life of the connection. This paper provides an overview of universal multimedia access (UMA), a concept for accessing multimedia content through a variety of possible schemes, and discusses some of the issues that arise regarding its deployment. In particular, UMA will provide a solution for adapting the delivered content when users attempt to access their choice irrespective of their terminal characteristics and communication infrastructure, as opposed to the assumption that the content remains fixed and the objective is to deliver the original content at all times. This recognition represents the impetus for the development of media descriptions and hence UMA;that is, the notion that valuable information can be derived from a variety of conversions of a multimedia content source. The issues discussed are future requirements on content servers and multimedia viewers, media conversions, UMA protocols, and UMA network architectures. The problems addressed are quality of service issues in network solutions for multimedia communications and reconfigurable architectures and network control based on source adaptations through media conversions and transcoding.

关键词： multimedia communications media description transcoding

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：