An on‐demand data broadcasting scheduling algorithm based on dynamic index strategy

On‐demand data broadcasting scheduling is an effective wireless data dissemination technique. Existing scheduling algorithms usually have two problems: (1) with the explosive growth of mobile users and real‐time individual requirements, broadcasting systems present a shortage of scalability, dynamics and timeliness (request drop ratio); (2) with the growth of intelligent and entertained application, energy consumption of mobile client cannot be persistent (tuning time). This paper proposes an effective scheduling algorithm LxRxW. It takes into account the number of lost requests during next item broadcasting time, the number of requests and the waiting time. LxRxW can reduce the request drop ratio. At the same time, the algorithm employs a dynamic index strategy to put forward a dynamic adjusting method on the index cycle length (DAIL) to determine the proper index cycle. Extensive experimental results show that the LxRxW algorithm has better performance than other state‐of‐the‐art scheduling algorithms and can significantly reduce the drop ratio of user requests by 40%–50%. The request drop ratio and accessing time of LxRxW with index increase by 1%–2% than LxRxW algorithm without index, but the tuning time decreases by 70%. The index strategy shows that when the index cycle length is less than 20units, it can significantly reduce the average tuning time but when the index cycle length continues increasing, the average tuning time will increase contrarily. DAIL can dynamically determine the length of index cycle. Moreover, it can reach optimal integrated performance of the request drop ratio, the average accessing time and the average tuning time. Copyright © 2013 John Wiley & Sons, Ltd.     

A scheduling scheme for continuous media data broadcasting with a single channel

Recently, various schemes for broadcasting continuous media data such as audio and video have been studied. Some of them have focused on reducing the waiting time of clients under the condition that clients can play data without interruption from beginning to end. These schemes usually employ multiple channels to broadcast continuous media data. However, clients for most broadcast systems such as wireless LAN, DVB and ISDB-T cannot receive data from multiple channels concurrently. In this paper, we propose and evaluate a scheduling scheme to reduce the waiting time of clients with a single channel. Preliminary results suggest that this scheme outperforms existing schemes.     

Multimedia data broadcasting strategies

Data broadcasting in support of multimedia applications requires efficient use of bandwidth resources in order to maximize the availability of playout content. A broadcast architecture has been specified by the Digital Video Broadcasting consortium to allow service providers to multiplex data, using various protocols, into an MPEG-2 transport stream. This architecture, however, has not specified how to optimize the use of the broadcast channel. This article discusses certain strategies, based on test and measurement, that have been implemented to maximize the use of the broadcast channel (satellite and cable) for supporting multimedia applications     

An error-correcting coding scheme for teletext and othertransparent data broadcasting

Nonprimitive and primitive Reed-Solomon (RS) codes (and product codes based on them) that can provide a very low bit error rate (BER) for the transparent data broadcasting feature of North American broadcast Teletext Specification (NABTS) are described. Transparent data consist of 8-b bytes, each without a parity-check bit, as contrasted with nontransparent data, which consist of 8 bit bytes, each of which has a parity-check bit in every byte. Specific applications for transparent error-coding codes constructed from RS codes in broadcast teletext broadcasting are discussed. Nonprimitive RS codes designed for nontransparent data broadcasting by NABTS teletext are derived, and powerful product forms of shortened nonprimitive Reed-Solomon codes are described     

An error-correcting code for data broadcasting and its error-correction capability

By using the vertical blanking period of television signals, it is possible to transmit coded data such as teletext, newspaper, telesoftware, music score, etc. However, the quality of ordinary TV channels is very poor for digital communications and a powerful error-correcting code is required to reliably transmit coded data. From the results of simulations using error pattern data collected in field tests and the comparison of various error-correcting codes under many conditions, it has been determined that the shortened (272, 190) majority-logic decodable difference-set cyclic code is a suitable code for NTSC TV signals. Moreover, the decoding algorithm for this code has been improved in order to increase the error-correction capability and a new LSI with this function has been developed. By using error-correcting codes proposed to date for teletext, it has been difficult to obtain a page error rate (PER) of 10⁻¹in many measurement points. However, PERs of less than 10⁻² can be obtained in this system, even when random noise, ghost interference, or waveform distortion are present and bit error rates (BERs) are 10⁻². This paper also gives PERs according to the error-data collected in field tests and shows that the error-correction capability increased equivalently up to 11 error-bits in a 272-bit by improving the decoding algorithm and the results of indoor and outdoor tests.     

短波广播频率调度工作回顾与展望

本文回顾了短波广播频率调度工作的发展历程,介绍了短波频率调度工作的开展情况．提出了构建短波广播频率调度综合管理体系的设想。     

QoS-aware adaptation for satellite multimedia broadcasting via hierarchical packet scheduling

With the unique broadcast nature and ubiquitous coverage of satellite networks, the synergy between satellite and terrestrial networks provides opportunities for delivering wideband services to a wide range of audiences over extensive geographical areas. This article concerns the optimization techniques pertinent to packet scheduling to facilitate multimedia content delivery over the satellite with a return channel via a terrestrial network. We propose a novel hierarchical packet scheduling scheme that allocates the resources at different parts of the network in response to network dynamics and link variations while under the system power/resource constraints. Simulations prove that the HPS scheme can effectively improve the end-to-end performance and resource utilization with desirable scalability and fairness features.     

一种考虑传感器精度的数据自适应加权融合算法

为增强多传感器测量数据融合效果,在综合考虑传感器初始精度与实际测量精度的基础上,提出了一种改进的自适应加权融合算法。将证据理论中的修正证据距离引入传感器实际测量数据间距离计算,基于计算得出的测量数据间距离生成各数据融合时的测量权重值。当传感器精度已知或者能够计算得出时,将基于传感器精度生成的固定权重与测量权重相综合,生成最终权重;当传感器精度未知且无法计算得出时,将测量权重作为最终权重。基于多种典型算例对所提融合算法进行验证,结果表明所提算法融合效果较好,具有一定的理论意义和较好的工程实用价值。     

Multimedia services and data broadcasting via satellite

Since 1995 EUTELSAT, as well as other service providers (in Europe and worldwide), in collaboration with industrial partners and research institutions have been developing digital platforms for providing multimedia services as well as data broadcasting via satellite services. These digital platforms are based on the same technologies as those used for the emerging digital television and radio services, namely Digital Video Broadcasting (DVB) and MPEG-2. These platforms will greatly improve the speed of multimedia services to the end user (e.g. up to 2 Mbit/s per session on an Internet connection) and will provide the possibility of downloading very large files in a very short time (e.g. downloading speeds of up to 40 Mbit/s per transponder) to a very large number of customers. By using the same technology as for digital television and radio, large economies of scale are foreseen, thus making these digital platforms very affordable on both the unlink side and the receiver side (e.g. less than $300 for the DVB-PC card kit)     

数据广播系统中浏览器的应用

１ 概述在数据广播系统中浏览器是一个重要的组成部分,它是电视机用户的交互窗口,用户可以在电视上浏览到丰富的数据信息（如天气预报、网上购物,股票交易等）,可以做到足不出户,便可知天下事,它使电视机的功能更加强大。此系统包含服务器端软件和客户端软件两部分（如图１）。服务器端软件将ＨＴＭＬ和ＥＰＧ等数据与数字视音频节目合成符合ＭＰＥＧ２标准的传输流;客户端软件则使用浏览器功能模块将数据信息在电视上显示给用户。由于完全遵照ＤＶＢＣ和ＭＰＥＧ２标准,因此,给用户带来极好的视听效果,而所有的功能实现对…     

DVB数据广播标准及实现

首先讨论ＤＢＶ数据广播标准，包括各种类型、服务信息表及其协议，然后讨论其实现方式。     

VOD系统多点广播调度策略研究

多点广播调度策略是大规模VOD系统设计的关键技术,介绍了几种基本的调度策略,提出了一种VOD系统调度模糊控制策略,给出了它的基本实现方法,这种模糊控制技术是一种有效提高VOD系统资源利用率的方法,同时它能大大降低用户平均等待时间,减少并发流数目,降低系统工作负载。     

CATV数据广播的智能解决方案

提出了用数据广播的智能解决方案来实现有线网与互联网的功能结合。在本系统中,数据广播服务器可以为用户提供有效的热点信息;客户端应用程序主动收听用户感兴趣的信息,并且在ＰＣ上实现将单向数据广播与已有的双向因特网连接无缝地结合起来,给用户提供一个虚拟的因特网环境,使用户可以方便快捷地访问网上信息。     

卫星数据广播系统简介

简要介绍了数字通信卫星VBI和IP两种数据广播技术,较详细地阐述了IP数据广播系统的特点、应用范围和系统组成。     

An efficient dynamic traffic light scheduling algorithm considering emergency vehicles for intelligent transportation systems

Traffic lights have been installed throughout road networks to control competing traffic flows at road intersections. These traffic lights are primarily intended to enhance vehicle safety while crossing road intersections, by scheduling conflicting traffic flows. However, traffic lights decrease vehicles’ efficiency over road networks. This reduction occurs because vehicles must wait for the green phase of the traffic light to pass through the intersection. The reduction in traffic efficiency becomes more severe in the presence of emergency vehicles. Emergency vehicles always take priority over all other vehicles when proceeding through any signalized road intersection, even during the red phase of the traffic light. Inexperienced or careless drivers may cause an accident if they take inappropriate action during these scenarios. In this paper, we aim to design a dynamic and efficient traffic light scheduling algorithm that adjusts the best green phase time of each traffic flow, based on the real-time traffic distribution around the signalized road intersection. This proposed algorithm has also considered the presence of emergency vehicles, allowing them to pass through the signalized intersection as soon as possible. The phases of each traffic light are set to allow any emergency vehicle approaching the signalized intersection to pass smoothly. Furthermore, scenarios in which multiple emergency vehicles approach the signalized intersection have been investigated to select the most efficient and suitable schedule. Finally, an extensive set of experiments have been utilized to evaluate the performance of the proposed algorithm.     

数据广播接收卡驱动程序设计

介绍一种数据广播接收卡的驱动程序的实现方法，它在MPEG－2和DVB－C标准的基础上，接收IP数据或MPEG－2传输流数据，用它可以进行有线电视系统的新闻、证券、文件、视频等广播数据的接收，也可以接收数字电视节目。     

Performance analysis of data scheduling algorithms for multi‐item requests in multi‐channel broadcast environments

Nowadays querying multiple‐dependent data items in a request is common in many advanced mobile applications, such as traffic information enquiry services. In addition, multi‐channel architectures are widely deployed in many data dissemination systems. In this paper, we extend a number of data productivity‐based scheduling algorithms and evaluate their performance in scheduling multi‐item requests in multi‐channel broadcast environments. We observe from the experimental results two performance problems that render these algorithms ineffective. Lastly, we discuss possible causes of these problems to give insights in the design of a better solution. Copyright © 2009 John Wiley & Sons, Ltd.     

Efficient heuristics for data broadcasting on multiple channels

The problem of data broadcasting over multiple channels consists in partitioning data among channels, depending on data popularities, and then cyclically transmitting them over each channel so that the average waiting time of the clients is minimized. Such a problem is known to be polynomially time solvable for uniform length data items, while it is computationally intractable for non-uniform length data items. In this paper, two new heuristics are proposed which exploit a novel characterization of optimal solutions for the special case of two channels and data items of uniform lengths. Sub-optimal solutions for the most general case of an arbitrary number of channels and data items of non-uniform lengths are provided. The first heuristic, called Greedy+, combines the novel characterization with the known greedy approach, while the second heuristic, called Dlinear, combines the same characterization with the dynamic programming technique. Such heuristics have been tested on benchmarks whose popularities are characterized by Zipf distributions, as well as on a wider set of benchmarks. The experimental tests reveal that Dlinear finds optimal solutions almost always, requiring good running times. However, Greedy+ is faster and scales well when changes occur on the input parameters, but provides solutions which are close to the optimum. This work has been supported by ISTI-CNR under the BREW research grant. Stefano Anticaglia received the bachelor’s degree in Computer Science from the University of Perugia (Italy) in 2005. At present, he is a student in the master’s of Computer Science of the University of Perugia. Ferruccio Barsi received the doctor engineering degree from the University of Pisa, Italy, in 1969. From 1969 to 1992 he has been with he National Council of Research at the Istituto di Elaborazione dell’Informazione, Pisa. Since 1992, he is a Full Professor of Computer Science in the Mathematics and Computer Science Department of the University of Perugia, Italy. His main contributions are in the areas of computer architecture, error-control coding, systems diagnosis, VLSI design, digital signal processing, and computer graphics. He is currently involved in researches concerning network security and wireless communications. Alan Bertossi was born in London (England) in 1956. He got the Laurea Degree summa cum laude in Computer Science from the University of Pisa (Italy) in 1979. Afterwards, he worked as a System Programmer and Designer. From 1983 to 1994 he was with the University of Pisa as a Research Associate first, and later as an Associate Professor. From 1995 to 2002 he was with the University of Trento (Italy), as a Full Professor. Since 2002, he has been with the Department of Computer Science of the University of Bologna (Italy), as a Professor of Computer Science. His main research interests are the computational aspects of high-performance, parallel, VLSI, distributed, fault-tolerant, and real-time systems. He has published about 40 refereed papers on international journals, as well as several papers in international conferences, workshops, and encyclopedias. He has authored a book (on design and analysis of algorithms, in Italian) and he served as a guest coeditor for special issues of Algorithmica, Discrete Applied Mathematics, and Mobile Networks and Applications. He is a member of the editorial board of Information Processing Letters. His biography is included in the 1999 edition of Who’s Who in the World and in the 2000 edition of Who’s Who in Science and Engineering. Since 1999, he has been a scientific collaborator at the Institute of Information Sciences and Technologies of the Italian National Research Council (ISTI-CNR, Pisa, Italy). During 2001–2003, he was the national coordinator of an Italian research project on algorithms for wireless networks. Lucio Iamele received the bachelor’s degree in Computer Science from the University of Perugia (Italy) in 2004. At present, he is working at Noranet (Italy) as a system programmer and designer. M. Cristina Pinotti received the Dr. degree cum laude in Computer Science from the University of Pisa, Italy, in 1986. During 1987–1999 she was a Researcher with the National Council of Research at the Istituto di Elaborazione dell’Informazione, Pisa. From 2000–2003 she was an Associate Professor at the University of Trento. From 2004, she is a Full Professor at the University of Perugia. In 1994 and 1995 she was a Research Associate at the Department of Computers Sciences, University of North Texas, Denton, TX. In 1997 she visited the Department of Computer Science, Old Dominion University, Norfolk, VA (USA). Her research interests are in wireless networks, sensor networks, design and analysis of algorithms, data broadcasting, channel assignment problems, graph coloring, multiprocessor interconnection networks, design and analysis of parallel algorithms, parallel data structures, distributed computer arithmetic, residue number systems, VLSI special purpose architectures. She has published about 50 refereed papers on international journals, in international conferences and workshops. She has been a guest co-editor for special issues of Mobile Networks and Applications, Wireless Networks and Journal of Parallel and Distributed Computing. She is a member of the editorial board of International Journal of Parallel, Emergent and Distributed Systems.     

Adaptive fast data broadcasting scheme for video-on-demand service

As we support video-on-demand (VOD) service with batching schemes, the bandwidth requirement will be very large for a popular movie. For a hot video, fast data broadcasting scheme substantially reduce the bandwidth requirements as compared with batching schemes. However, the fast data broadcasting scheme needs to predict which movie is hot. If the prediction is not accurate, the allocated bandwidth will be wasted. This paper presents a new data broadcasting scheme for VOD service. For a movie, as it is popular, the new scheme will work like the fast data broadcasting scheme to save the communication bandwidth. If there is no request for the movie, the new scheme will not allocate bandwidth for the movie. Therefore, the bandwidth allocation for a movie is always efficient whether or not the movie is popular