Real-time Broadcast Research Articles

Scheduling Periodic Continuous Queries in Real-Time Data Broadcast Environments

On-demand broadcast is a promising data dissemination approach in mobile computing environments thanks to its adaptability and scalability for large-scale and dynamic workload. An important class of emerging data broadcast applications needs to monitor multiple time-varying data items continuously to be kept aware of the up-to-date information. This paper investigates the broadcast schedule problem for disseminating timely data to periodic continuous queries, and a systematic and highly efficient solution for applications of this type is provided. In particular, we propose a novel measure, called Bandwidth Utilization, to quantify the minimum bandwidth demand of a periodic continuous query set. The timing predictability can be ensured if a set of periodic continuous queries passes a bandwidth utilization based schedulability test. The schedulability test techniques are also extended to deal with dynamic query arrival and departure. An efficient online scheduling algorithm, called RM-UO, is developed, which can fulfill the timing constraints combined with the proposed query release and deletion policies. To demonstrate the effectiveness of theoretical results, an illustrative algorithm implementation is presented along with comprehensive performance analysis. Simulation results show that our solution offers nice timing predictability whereas other comparable best effort scheduling algorithms such as SIN-Q and DTIU experience different deadline miss ratios at different query workloads.

Web 2.0 como estrategia comunicativa en los eventos protocolares y de relaciones públicas. Boda real británica (24 de abril 2011)

Con la explosión del recurso interactivo llamado Web 2.0, la comunicación se ha modificado, evolucionando, casi a la fuerza, para adaptarse al tiempo presente y a la fugacidad de la información dentro del nuevo horizonte comunicativo que es Internet. Las nuevas audiencias, con parámetros de exigencia distintos a la tradicionalmente pasiva audiencia audiovisual, ha requerido la realización de este esfuerzo adaptativo en materia de comunicación. Este cambio de modelo de comunicación afecta desde la retransmisión informativa hasta la de los grandes eventos internacionales protocolares y políticos, que han sufrido igualmente esta adaptación a los avances de la tecnología del Web 2.0. Adaptación que se refiere a la interactividad, participación, cercanía, a la práctica inmersión del receptor en la emisión en tiempo real. Tres grandes acontecimientos han afectado a los paradigmas de retransmisión de grandes eventos protocolares y políticos: por una parte, la boda de la Reina Isabel de Inglaterra en 1947 que fue la primera retransmisión efectuada. La segunda supuso la de mayor audiencia mundial en tiempo real: la boda de Diana de Gales y el Príncipe Carlos de Gales. El tercer evento al que hacemos referencia, y al que hemos dedicado observación, investigación y reflexión, es la boda de Guillermo y Catalina, en abril de 2011.

Real-Time Precise Point Positioning in NAD83: Global and Regional Broadcast Corrections Compared

Real-time precise point positioning (PPP) is possible through the availability of the real-time satellite orbit and clock corrections to broadcast ephemeris, the real-time broadcast corrections (BCs). The real-time BCs are currently available in global as well as in regional reference frames. In this contribution, PPP usage and the performance of these global and regional BCs are analyzed for the North American Datum of 1983 (NAD83). The limitations of the current regional BC approach for NAD83 are identified and the coordinate differences it leads to compared with the traditional global BC approach are shown. Although the biases as a result of the different reference frame usage are shown to be subcentimeter, it is also shown how they can be reduced or eliminated by modifying either the PPP algorithm or the regional BC approach. Analyses were performed for three different PPP variants, a single-frequency ionosphere-free variant, a dual-frequency ionosphere-free variant, and a single-frequency ionosphere-corrected variant.

Wireless multi-gigabit data transmission using active MMIC components at 220 GHz

In this paper we present a wireless data link for multi-gigabit transmission in the mmW frequency range. The link is realized using waveguide modules based on fully integrated 50 nm metamorphic high electron mobility transistor (mHEMT) transmit and receive millimeter wave monolithic integrated circuits (MMICs) and provides transmission of data rates up to 12.5 Gbit/s modulated on a 220 GHz carrier. The receiver input sensitivity is characterized down to values of −38.6 dBm and shows an error rate of 3.0 × 10−9. Measurements using a coherent link setup show bit error rates better than 1.6 × 10−9 for a data rate of 10 Gbit/s and a transmission distance of 2 m. For a distance of 20 m a real-time Digital Video Broadcasting – Satellite (DVB-S) television transmission is realized. The signal quality after the wireless link is sufficient for a commercial DVB-S receiver to display the television programs.

GNSS precise point positioning in regional reference frames using real-time broadcast corrections

As a result of the Real-Time IGS Pilot Project (RT-IGS) and the EUREF Real-Time Analysis Project (EUREF-RT), real-time GNSS satellite orbit and clock cor- rections to broadcast ephemeris, the so-called real-time broadcast corrections (BC), have become available for the application in precise point positioning (PPP). The real- time BCs are currently available in global as well as in regional reference frames. In this contribution the PPP usage and performances of these global and regional BCs are analysed for the Australian continent. We identify the limitations of the current regional BCs, which results in scale-induced biases, and show how they can be improved. We also present an alternative, more user friendly, approach for regional BCs. It provides PPP users with simple means to correct for the biases of the regional approach.

The Framework Design of E-Yuan Multimedia System

E-Yuan multimedia system is developed for the rich audio and video resource on the Internet and on its server side, it can automatically search and integration of network video and audio resources, and send to the client side for the user in real-time broadcast TV viewing, full use of remote control operation, Simply it’s a very easy to use multimedia system. This article introduces its infrastructure, main technical ideas and you can also see some details about server side and client side.

A Home Multimedia Control Centers of Improved Design

E-Yuan multimedia system is developed for the rich audio and video resource on the Internet and on its server side, it can automatically search and integration of network video and audio resources, and send to the client side for the user in real-time broadcast TV viewing, full use of remote control operation, Simply it’s a very easy to use multimedia system. This article introduces its infrastructure, main technical ideas and you can also see some details about server side and client side. At the same time, the improvement on how to collect and integrate video resources is comprehensively elaborated.

On the reliability and performance of real-time one-hop broadcast MANETs

Recently, broadcast communications in mobile ad hoc networks (MANETs) have been deployed in many mission-critical applications. So far, most investigations of such broadcast networks focus on multi-hop connectivity taking all one-hop links for granted. In this paper, the reliability and performance of real-time one-hop broadcast services in IEEE 802.11 based MANETs are investigated analytically and by simulation. Having specified possible applications and the features of IEEE 802.11 broadcast communication in dynamically self-organized networks under harsh communication environment, analyses are conducted to derive closed form expressions of the reliability and performance indices for both one-dimensional (1-D) and two-dimensional (2-D) broadcast MANETs: packet reception rate (PRR) and packet transmission delay. The proposed analytical models account for the impact of broadcast hidden terminal problem, message arrival interval, backoff counter process, space distributions of nodes, and fading transmission channel on the reliability and performance of the broadcast MANETs. As an example, the proposed models are applied to the evaluation of safety-related inter-vehicle communication on a highway. From the obtained numerical results under various offered traffic and network parameters, new observations and effective enhancement suggestions are given.

Secure and Scalable Content Sharing Framework for Next-Generation IPTV Service

Due to an increase in multimedia content and the acceleration of digital convergence, demand for next-generation IPTV service is rapidly growing. IPTV service seamlessly provides both real-time broadcasting and content sharing services on diverse terminals through complex networks. In this paper, a secure and scalable content sharing framework is proposed for next-generation IPTV service. The proposed framework has an advantage over conventional content protection techniques in producing scalable content with transcodable, adjustable, and perceptual security features. Moreover, it ensures end-to-end security over the entire service range based on a single security mechanism. The suitability of the proposed approach is demonstrated experimentally using a practical service scenario with real-world environments. The experiments show that the proposed approach can provide several different levels of content security, from a perceptual level to an almost unintelligible level, while keeping the additional time overhead low. Consequently, it is expected that use of this security technology alone can have a practical contribution in creating new business opportunities for IPTV services.

Network system for wide area DGNSS

A differential global navigation satellite system (DGNSS) is always used to broadcast augmentation messages for GNSS to receivers in the covering areas through geostationary earth orbit (GEO) satellites to improve the accuracy, reliability, and integrity of navigation. GEO broadcasting is an efficient strategy for avionic applications and other modes of transport. For some applications though, it may be of interest to broadcast additional augmentation messages through other transmission means. For instance, it may be difficult for GEO reception in cities or indoors because of building obstacles. Real-time broadcasting of navigation augmentation messages through the internet is an important hot-spot of research. Based on characteristics of navigation augmentation messages, combined application layers multicast with i3 (internet indirection infrastructure) multicast, is presented herein with a hierarchy mix multicast system based on node heterogeneity to broadcast differential correction messages. The qualities of the system network structure are analyzed. After the securities requirements are analyzed, the types and solutions of security issues were briefly studied.

Live surgery – patient, professional and societal considerations

'What's the alternative to live surgery? Dead surgery?' This was the legitimate comment made by the teenage child of Dr Stephanie Bown, Director of Policy at the Medical Protection Society. As Dr Bown pointed out when she relayed this quote at our recent policy seminar, we should always be clear about the issue in question – real-time broadcast of a surgical procedure to an audience.

Reliable Wireless Broadcast with Linear Network Coding for Multipoint-to-Multipoint Real-Time Communications

This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for ad-hoc networks like video game networks. We aim to achieve highly reliable MPtoMP broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the encoded packet is broadcasted in the next sequence as a piggy-back for its native packet. To prevent increase of overhead in each packet due to piggy-back packet transmission, network coding vector for each node is exchanged between all nodes in the negotiation phase. Each user keeps using the same coding vector generated in the negotiation phase, and only coding information that represents which user signal is included in the network coding process is transmitted along with the piggy-back packet. Our simulation results show that the proposed method can provide higher reliability than other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with a practical degree of complexity when installed on current wireless devices.

Strategic Management Implications of a Consumer Value Perspective on Mobile Tv

Understanding of consumer experienced value in mobile services continues to be a strategic issue in the information systems literature. This is no different with Mobile TV that has become feasible with the convergence of telecommunication infrastructures, computer technology, and media content services. Mobile TV offerings are defined as real-time broadcast transmissions of content to mobile devices. We review mobile services literatures on consumer value creation and identify a gap in our understanding of how supplier firm's consumer-focused strategies may aid in consumption processes and thereby increase payments from consumers. We apply the perspective of consumer benefits experienced (CBE) to provide insight into how supplier firms may be able to increase consumer value. Value increases with greater consumer service-specific knowledge, and leveraging and complementing this knowledge across different offerings. Increased service-specific knowledge can also reduce demands on the consumer that can create important switching costs while increasing consumer-experienced value. This paper contributes to innovation research on mobile services.

Efficient repair mechanism of real-time broadcast services in hybrid DVB-SH and cellular systems

In order to ensure good video quality and location-independent access to multimedia content, digital video broadcasting-satellite service to handhelds (DVB-SH) takes advantage of several innovative techniques. The major one is the forward error correction (FEC) scheme implemented at the link layer called multiprotocol encapsulation-inter-burst FEC (MPE-IFEC). MPE-IFEC supports reception in situations of long duration erasure spanning several consecutive time slice bursts (lasting several seconds) due to characteristics of the land mobile satellite channel which are easily hampered by obstacles such as trees, buildings, or overpasses. However, when deep signal fades last for larger durations, the MPE-IFEC correction capacity is insufficient and MPE-IFEC fails, causing a service interruption. In this paper, we propose a repair mechanism and a suitable architecture for real-time streaming service error handling with reduced degrading effects such as picture freeze, video frame degradation, and video lag. Based on an analytical model of the performance of the MPE-IFEC, an iterative algorithm is proposed where the probability of recovery of lost bursts is computed and updated. The proposed algorithm controls the retransmission request on the cellular network. Simulation results show that by recovering only some specific lost bursts via the cellular path, the quality of experience here expressed in terms of burst error rate is improved.

Scheduling on-demand broadcast with timing constraints

In a distributed system, broadcasting is an efficient way to dispense data in certain highly dynamic environments. While there are several well-known on-line broadcast scheduling strategies that minimize wait time, there has been little research that considers on-demand broadcasting with timing constraints. One application which could benefit from a strategy for on-demand broadcast with timing constraints is a real-time database system. Scheduling strategies are needed in real-time databases that identify which data item to broadcast next in order to minimize missed deadlines. The scheduling decisions required in a real-time broadcast system allow the system to be modeled as a Markov Decision Process (MDP). In this paper, we analyze the MDP model and determine that finding an optimal solution is a hard problem in PSPACE. We propose a scheduling approach, called Aggregated Critical Requests (ACR), which is based on the MDP formulation and present two algorithms based on this approach. ACR is designed for timely delivery of data to clients in order to maximize the reward by minimizing the deadlines missed. Results from trace-driven experiments indicate the ACR approach provides a flexible strategy that can outperform existing strategies under a variety of factors.

LIVE! From the Sim Lab: Broadcasting a Simulated Patient–Care Scenario as a Teaching–Learning Strategy in a Nursing Fundamentals Clinical Lab

At one baccalaureate program, the faculty and staff feel strongly that simulation experiences are such an effective teaching–learning strategy that they warrant inclusion in the very first clinical nursing course, an on-campus weekly 2-hour Fundamentals of Nursing lab experience. The innovative use of real-time broadcast technology and simulated patient care scenarios has proved to be a winning combination for these novice nursing students and at the same time has made optimal use of limited lab time and resources. LIVE! From the Sim Lab was highly effective in demystifying the simulation experience for students and introducing them to the patient care scenario format for practice and evaluation.

Efficient Retransmission Architecture of Digital Broadcast Services over IPTV Networks

This paper describes architecture for supporting legacy digital broadcast services over IPTV networks. Legacy services refer to pre made real-time broadcast streams based on open standards such as MHP, ACAP, and OCAP. They use MPEG-2 TS as delivery protocol, but this is not a good choice for IPTV as it is defined in view of unidirectional media such as terrestrial or satellite networks. The proposed architecture retransmits digital broadcast services using IP-oriented protocols including service delivery, service discovery and selection, XML-based application signaling, and integrated application execution engines.

Providing Data Items with Time Constraints in Multi-Channel Broadcasting Environments

In a mobile computing system, users carrying portable devices can access database services from any location without requiring a fixed position in the networking environment. Some examples of strategies supported by databases in mobile computing include location dependent queries, long-lived transactions that require migration of data into the portable devices, form-based transactions, and online information report. Within a mobile computing environment, the need for a realtime database management model is strong, because one of the basic requirements in mobile data management is to provide real-time response to transactions of the underlying strategies. However, the resource constraints of mobile computing systems make it difficult to satisfy timing requirements of supported strategies. Low bandwidth, unreliable wireless links, and frequent disconnections increase the overhead of communication between mobile hosts and fixed hosts of the system. There are many situations in which we need to incorporate real-time constraints in broadcasting systems for mobile environments. In this paper, we study broadcast scheduling strategies for pushbased broadcast with timing constraints in the form of deadlines. Unlike previously proposed scheduling algorithms for broadcast systems which aim to minimize the mean access time, our goal is to identify scheduling algorithms for broadcast systems that ensure requests meet their deadlines. We present a study of the performance of traditional real-time strategies and mobile broadcasting strategies, and demonstrate that traditional realtime algorithms do not always perform the best in a mobile environment. We propose a multichannel model based on pushbased real-time broadcast system and also provide an efficient scheduling algorithm, called dynamic adjustment with time constraint (DATC), which is designed for timely delivery of data to mobile clients.

Forward of Special Issue on “Mobile System, Agent Technology, and Web Services”

Forward of Special Issue on “Mobile System, Agent Technology, and Web Services”

Prakash

In this paper, we present a high speed optical motion capture method that can measure three dimensional motion, orientation, and incident illumination at tagged points in a scene. We use tracking tags that work in natural lighting conditions and can be imperceptibly embedded in attire or other objects. Our system supports an unlimited number of tags in a scene, with each tag uniquely identified to eliminate marker reacquisition issues. Our tags also provide incident illumination data which can be used to match scene lighting when inserting synthetic elements. The technique is therefore ideal for on-set motion capture or real-time broadcasting of virtual sets. Unlike previous methods that employ high speed cameras or scanning lasers, we capture the scene appearance using the simplest possible optical devices - a light-emitting diode (LED) with a passive binary mask used as the transmitter and a photosensor used as the receiver. We strategically place a set of optical transmitters to spatio-temporally encode the volume of interest. Photosensors attached to scene points demultiplex the coded optical signals from multiple transmitters, allowing us to compute not only receiver location and orientation but also their incident illumination and the reflectance of the surfaces to which the photosensors are attached. We use our untethered tag system, called Prakash, to demonstrate methods of adding special effects to captured videos that cannot be accomplished using pure vision techniques that rely on camera images.