A Broadcasting Scheme Considering Units to Play Continuous Media Data

Due to the recent proliferation of digital broadcasting systems, various schemes for broadcasting continuous media data such as music or movies have been studied. In general broadcasting systems, since clients have to wait until their desired data are broadcast, these schemes reduce the waiting time by dividing the data into several segments of equal size. However, continuous media data often have units for playing portions of the data. For example, data encoded by MPEG2 can be played every GOP (group of pictures). In this paper, we propose a scheme to reduce the waiting time considering the units. Our proposed scheme divides a continuous media data at every unit. By scheduling divided data so that clients finish receiving a unit before starting to play the unit, waiting time is effectively reduced.     

基于DVB标准的数据广播通用压缩传输协议

结合当前的数据广播业务,提出了一种基于DVB标准的优秀通用数据压缩传输协议,解决了实际应用中数据广播的瓶颈问题.     

数据广播在文化传媒领域的合理化运作

数据广播是现阶段一种新的文化传媒体系,随着数字电视的不断发展完善,数据广播在信息产业飞速发展的今天,逐渐成为新时期信息传播的主要媒介方式,阐述数据广播在当今社会信息领域的存在形态、发展方向以及如何合理、高效地运营这样一种增值业务。     

P2P大规模流媒体调度技术研究

随着宽带、IPV6、3G等技术的日渐成熟,流媒体应用已成为Internet承载的重要业务.调度技术是保证大规模可信流媒体服务质量的关键问题之一.对典型流媒体调度和分发技术进行综述,归纳分析了基于P2P网络环境下树型、网状以及混合拓扑结构的流媒体技术的优缺点,对mesh网下的资源发布于查找、服务节点选择、数据块调度等进行了重点分析和评述.依据流媒体应用的发展趋势,预测了P2P大规模可信流媒体调度技术在适应复杂网络,及结合云技术等方面的研究方向与内容.     

A Distributed Intelligent Broadcasting Protocol for Mobile Ad Hoc Networks

The control and routing performances of mobile ad hoc networks (MANETs) depend upon the efficiency of the network-wide broadcasting schemes that are in place. Ad hoc networks are often characterized by poor infrastructure quality, limited resources, dynamic variation and a need for mobility; therefore, ease of deployment, adaptability and potential for energy-savings are the primary drivers considered in the design of typical broadcasting schemes. This paper proposes a distributed intelligent broadcasting protocol (DIBP) that is capable of dynamically determining the broadcasting nodes in a MANET, based upon the distribution of network nodes. This eliminates the need for active network monitoring and periodical maintenance is not required. In addition, the distributed intelligent broadcasting protocol employs an adjustable parameter for determining the broadcasting node, broadcasting timing and the number of broadcasting nodes. This parameter can be changed dynamically based on different operational requirements; such as energy savings, hop count, network delay and other similar targets. Simulations of networks employing the protocol yield results showing that the DIBP performs better in terms of delivery delay, number of rebroadcast nodes, and delivery ratio.     

ZBP: A Zone-Based Broadcasting Protocol for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) have been widely used in motoring and collecting interests of environment information. Packet flooding or broadcasting is an essential function for establishing a communication path from sink node to a region of sensor nodes. However, flooding operation consumes power and bandwidth resources and raises the packet collision and contention problems, which reduce the success rate of packet transmissions and consume energy. This article proposes an efficient broadcasting protocol to reduce the number of sensor nodes that forward the query request, hence improves the packet delivery rate and saves bandwidth and power consumptions. Sensor node that received the query request will dynamically transfers the coordinate system according to the zone-ID of source node and determines whether it would forward the request or not in a distributed manner. Compared with the CBM and traditional flooding operation, experimental results show that the proposed zone-based broadcasting protocol decreases the bandwidth and power consumptions, reduces the packet collisions, and achieves high success rate of packet broadcasting.Chih-Yung Chang received the Ph.D. degree in Computer Science and Information Engineering from National Central University, Taiwan, in 1995. He joined the faculty of the Department of Computer and Information Science at Aletheia University, Taiwan, as an Assistant Professor in 1997. He was the Chair of the Department of Computer and Information Science, Aletheia University, from August 2000 to July 2002. He is currently an Associate Professor of Department of Computer Science and Information Engineering at Tamkang University, Taiwan. Dr. Chang served as an Associate Guest Editor of Journal of Internet Technology (JIT), Special Issue on “Wireless Ad Hoc and Sensor Networks” (2004) and a member of Editorial Board of Tamsui Oxford Journal of Mathematical Sciences (2001–2005). He was an Area Chair of IEEE AINA′2005, Vice Chair of IEEE WisCom2005, Track Chair (Learning Technology in Education Track) of IEEE ITRE′2005, Program Co-Chair of MNSA′2005, Workshop Co-Chair of INA′2005, MSEAT′2003, MSEAT′2004, Publication Chair of MSEAT′2005, and the Program Committee Member of ICPP′2004, USW′2005, WASN′2005, and the 11th Mobile Computing Workshop. Dr. Chang is a member of the IEEE Computer Society and IEICE society. His current research interests include wireless sensor networks, mobile learning, Bluetooth radio systems, Ad Hoc wireless networks, and mobile computing.Kuei-Ping Shih received the B.S. degree in Mathematics from Fu-Jen Catholic University, Taiwan, Republic of China, in June 1991 and the Ph.D. degree in Computer Science and Information Engineering from National Central University, Taiwan, Republic of China, in June 1998. After two years of military obligation, he joined the faculty of the Department of Computer Science and Information Engineering, Tamkang University, Taiwan, Republic of China, as an assistant professor in 2000. Dr. Shih served as a Program Area Chair in the IEEE International Conference on Advanced Information Networking and Applications (AINA), 2005, and as a Technical Track Chair in the IEEE International Conference on Information Technology: Research and Education (ITRE), 2005. Dr. Shih’s current research interests include wireless networks, sensor networks, mobile computing, and network protocols design.Dr. Shih is a member of the IEEE Computer and Communication Societies and Phi Tau Phi Scholastic Honor Society.Shih-Chieh Lee received the B.S. degree in Computer Science and Information Engineering from Tamkang University, Taiwan, in 1997. Since 2003 he has been a Ph.D. Students in Department of Computer Science and Information Engineering, Tamkang University. His research interests are wireless sensor networks, Ad Hoc wireless networks, and mobile/wireless computing.     

A Maximum-Residual Multicast Protocol for Large-Scale Mobile Ad Hoc Networks

Routing problems have become highly challenging because of the popularity of mobile devices. This paper targets power-aware routing when network topologies and data traffic may change quickly in an unpredictable way. We propose a distributed algorithm and its realization to maximize the minimum residual energy of all the nodes for each multicast, where no global information is assumed to be efficiently maintained at any node. A transient multicast tree is established on demand and derived based on the autonomous decisions of intermediate nodes. We prove that the derived tree is loop-free and theoretically optimal in the maximization of minimum residual energy. The performance of the proposed protocol was evaluated over NS2 with a series of simulations for which we have very encouraging results.     

数据广播的发展与思考

数据广播是第三种类型的广播。本文从分析数据广播的定义与分类出发，简要综述了调频多工数据广播的发展历史与现状，分析了它的主要作用；简要介绍了调幅多工数据广播的进展。综述了欧洲图文电视、隐蔽字幕、电传软件、收费数据广播与ＰＤＣ的发展，分析美国隐蔽字幕“２１行业务”的新进展与日本的电视传真广播的发展。最后对发展我国数据广播提出了看法与建议。     

Adaptive Meeting Scheduling for Large-Scale Distributed Groupware

This paper introduces a novel approach of collective scheduling among a community of distributed users. This approach, named Distributed Adaptive Scheduling (DAS), deploys flexible, lightweight agents to quickly find and suggest suitable solutions of scheduling for a large number of users. The DAS agents can move from one machine to another to co-ordinate mutually acceptable solutions for a proposed meeting. They also possess behavioural intelligence, by making adaptive decisions about next actions according to current environment and conditions. As a consequence, quick and efficient scheduling can be achieved for users located at different places. Experimental results have proved that DAS is especially suitable for large-scale distributed scheduling, and scheduling with complex calendars. The DAS approach has been successfully integrated with a personal assistant agent platform to provide completely automatic meeting scheduling for both stationary and mobile users. This revised version was published online in July 2006 with corrections to the Cover Date.     

IP多播和广播技术在PPPoE协议上的扩展

本文探讨了ＩＰ多播和广播技术在ＰＰＰｏＥ协议上的应用，并就其性能不足之处提出了一种改进方法。     

一种可重构流媒体调度算法

针对现有流媒体算法在异构环境下性能恶化的问题,论文提出一种支持用户异构性的可重构流媒体调度算法RSMS算法。该算法引入了追赶流的概念,能重构追赶流的速率来服务于具有不同接收带宽的异构用户,并最终通过流合并达到资源共享的目的。分析了RSMS算法的最佳组播调度间隔、所需的平均服务器带宽和服务器带宽需求分布。仿真实验表明该算法简单高效,可扩展性好。     

无线网络中中继协助的媒体接入协议

IEEE 802.11在物理层支持多速率.目前已提出许多机制通过自动调整速率充分利用多速率能力.本文观察到在无线网络中,相对于单跳的低速率链路,多跳高速率的路径可以减少信道占用时间,并提出了中继协助的媒体接入协议(Relay Aided Media Access,RAMA).RAMA利用中继节点将一跳低速链路拆为两跳高速链路.大量仿真结果表明,RAMA能够提供更好的吞吐量和时延性能.     

一种适用于自组网的流媒体协议设计

本文基于自组网的应用背景,在分析了传统流媒体协议特性的基础上,进行了自组网应用层信令面及用户面的协议设计。该协议以SIP和RTP/RTCP协议为蓝本,针对自组网节点平等,移动性强及无线传输质量差的网络特性,对传统流媒体协议的架构及呼叫流程进行了更改,使其适用于自组织网络,是一种可行的自组网流媒体协议。     

一种新的三维FANETs跨层自适应广播协议

针对盲目广播带来的广播风暴问题,该文提出一种新的3维FANETs自适应广播协议NABP。NABP应用跨层设计的方法,在维持原有协议层间结构分离的基础上,允许路由层共享MAC层的接收信号强度信息,并根据转发分组时增加通信范围计算出转发概率,倾向于让增加通信范围大的节点以高概率转发分组,从而减少了分组在网络中的重复传输,降低了节点间的竞争和碰撞,提高广播效率。NS-2仿真结果表明：与flooding + 802.11和fp-flooding+802.11协议相比,NABP提高了转播节省率、减少了平均端对端延迟和平均丢包率。     

A MultikeyRank Model Based on Ontology for Large-Scale Semantic Data

In order to provide users with intelligent retrieval services over large-scale semantic data, this paper proposes a MultikeyRank model. ORDPATHs is adopted to encode ontology classes defined in TBox and an inverted index is constructed according to the structured charac- teristics and semantic association of RDF data. A new query mode with one primary keyword and several auxil- iary keywords is designed. To reflect the user＇s perference objectively, the membership degree for ontology classes corresponding to the primary keyword is calculated based on the evidence theory and thus the MultikeyRank algo- rithm is formulated by extending the BM25F model accord- ingly. The proposed model was implemented in the self- developed distributed large-scale RDF data server “Jing- wei” and experimental results show that compared with BM25F, the evaluation indexes for P@5, P@10, P@15 and MAP are improved by 27.6%, 24.3%, 18.5% and 3.7% ,re- spectively.     

A Cross-Layer Packet Scheduling Scheme for Multimedia Broadcasting via Satellite Digital Multimedia Broadcasting System [Advances in Mobile Multimedia]

In recent years, multimedia content broadcasting via satellite has attracted increased attention. The satellite digital multimedia broadcasting (S-DMB) system has emerged as one of the most promising alternatives for the efficient delivery of multimedia broadcast multicast service (MBMS). The design of an efficient radio resource management (RRM) strategy, especially the packet scheduling scheme, becomes a key technique for provisioning multimedia services at required quality of service (QoS) in S-DMB. In this article, we propose a novel cross-layer packet scheduling scheme that consists of a combined delay and rate differentiation (CDRD) service prioritization algorithm and a dynamic rate matching (DRM)-based resource allocation algorithm. The proposed scheme considers multiple key factors that span from the application layer to the physical layer, aiming at simultaneously guaranteeing diverse QoS while utilizing radio resources efficiently under the system power and resource constraints. Simulation results demonstrate that the proposed cross-layer scheme achieves significantly better performance than existing schemes in queuing delay, jitter, and channel utilization.     

A DSFBC-OFDM for a Next Generation Broadcasting System With Multiple Antennas

In this paper, we propose a differential space-frequency block code-orthogonal frequency division multiplexing (DSFBC-OFDM) scheme as a multiple-input multiple-output (MIMO) transmission technique for next generation broadcasting system. A linear decoding method for DSFBC, which performs comparably to the ML decoding method, is derived for the cases of two or four transmit antennas. A simple table lookup method is proposed to improve the efficiency of the encoding/decoding process of DSFBC for the case of non-constant modulus constellations. This not only reduces the computational load, but also removes the necessity of channel estimation. Also, synchronization techniques with a DSFBC-encoded phase reference symbol (PRS) are discussed. Finally, an MIMO channel model for the next generation broadcasting system is developed by extending the 3GPP MIMO model to fit broadcasting environments. The MIMO channel model is then used to compare BER performances of differential space block code schemes for various channel environments. Simulation results show that the DSFBC-16QAM scheme using either four transmit antennas with one receive antenna or two transmit antennas with two receive antennas achieves a performance gain of 12 dB, with a data rate twice faster than that of the conventional DQPSK scheme     

基于分布式时隙调度协议的战术互联网媒体访问控制技术

在分析现有移动无线网络TDMA时隙调度问题的基础上,根据战术互联网骨干网拓扑与业务需求,结合跳频电台的特点,提出了一种新的动态分布式TDMA时隙调度协议(DTSP),能够适应不同业务需求,支持单播、广播和组播.DTSP协议以无冲突的预留提高系统吞吐量,以渐增方式适应动态拓扑变化,动态调整的开销较小.最后,以DTSP时隙单播预留协议为例,进行了详细分析和复杂度计算.     

On Channel Allocation for Heterogeneous Data Broadcasting

We explore in this paper the problem of generating broadcast programs in a heterogeneous data broadcasting environment, in which disseminated data items can be of different sizes. Given the broadcast database and the number of channels, we first derive the analytical model of the heterogeneous data broadcasting to obtain the average waiting time of mobile users, and prove the allocation problem as an NP-complete problem. In order to solve such problem, we propose a two-phase architecture to perform channel allocation. Algorithm DRP (Dimension Reduction Partitioning) is employed to perform rough allocation to derive the satisfactory solutions, whereas mechanism CDMS (Cost-Diminishing Movement Selection) is used for fine allocation to achieve local optimum solutions. In addition, we also propose algorithm GA-CDMS according to the concept of hybrid genetic algorithm for comparison purposes. GA-CDMS can perform global search more accurately and efficiently than conventional genetic algorithm GA and the suboptimum that GA-CDMS achieves will be very close to the optimal solution. In the experiments, we consider the important issues such as accuracy, scalability, diversity and the efficiency. From the experimental results, we show that the proposed two-phase channel allocation is very practical in performing an effective channel allocation with high efficiency in a heterogeneous broadcasting environment.