T. D. C. Little and A. Ghafoor, "Multimedia synchronization protocols for broad-band integrated services," IEEE Trans. Commun., vol. 9, pp. 1368--1382, Dec. 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....so utilizados para sincronizar fluxos relacionados, descrita por Nicolaou [Nico90] No esquema de Ferrari [Ferr92] descrito um mecanismo distribudo para controlar a variao do atraso (jitter) em redes que tm os comutadores e as operaes de comutao muito complexos. O modelo de Little e Ghaffor [LiGh91] utiliza Redes de Petri para a Composio de Objetos (OCPNs) a fim de especificar as relaes temporais entre os objetos multimdias; enquanto que Woo et al. WQG94] propem uma extenso da OCPN, a XOCPN (eXtended Object Composition PetriNet) onde objetos so divididos em subobjetos a fim de melhor ....

T. D. C. Little e A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE Journal on Selected Areas in 9, pp. 1368-1382, dezembro de 1991.

....na identificao das relaes causais entre unidades de informao de um ou vrios fluxos. A tcnica proposta por Qazi et al. QWG93] para comunicao de objetos multimdias distribudos, utiliza um modelo estendido (XOCPN) da rede de Petri temporizada para composio de objetos, proposto por Little Ghafoor [LiGh90a, LiGh91b]. Woo et al. WQG94] propem camadas de protocolos de sincronizao, baseadas no modelo XOCPN, as quais destinam se comunicao de informaes multimdias pr orquestradas. Um sistema multimdia qualquer sistema ou aplicao que suporte o processamento integrado de vrios tipos de mdias com pelo menos uma ....

....de eventos concorrentes e assncronos. No modelo OCPN, os lugares esto relacionados com a utilizao de recursos e possuem um tempo de durao. No entanto, o disparo de uma transio na OCPN um evento instantneo. Atravs da OCPN, possvel especificar as diversas relaes temporais entre objetos multimdias [LiGh91b], pois esta descreve relaes temporais do tipo antes , depois , durante , inicia junto , termina junto etc. Os recursos associados aos lugares da OCPN so relacionados com os tipos de objetos, tais como udio, vdeo, texto etc. As OCPNs so redes do tipo srie paralela (no possuindo realimentao) ....

[Article contains additional citation context not shown here]

Little, T.D.C. e Ghafoor, A., "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE J. Select. Areas in Commun., vol. 9, n 9, pp. 1368-82, dezembro de 1991.

....dos tipos antes, depois, durante e outras, num total de treze [LiGh90] Os dados envolvidos nas aplicaes que se servem dos mecanismos de sincronizao sinttica so chamados dados pr orquestrados [LiDu96] Nos ltimos anos, vrias tcnicas de sincronizao foram propostas. O modelo de Little e Ghaffor [LiGh91] utiliza Redes de Petri para a Composio de Objetos (OCPNs) a fim de especificar as relaes temporais entre os objetos multimdias. Um extrator de dependncias condicionais proposto por Carmo e Courtiat [CaCo96] de modo a reforar o poder da sincronizao temporal. A tcnica de Escobar et al. EPD94] ....

T. D. C. Little e A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE Journal on Selected Areas in Communications, vol. 9, n o 9, pp. 1368-1382, dezembro de 1991.

....na identificao das relaes causais entre unidades de informao de um ou vrios fluxos. A tcnica proposta por Qazi et al. QWG93] para comunicao de objetos multimdias distribudos, utiliza um modelo estendido (XOCPN) da rede de Petri temporizada para composio de objetos, proposto por Little Ghafoor [LiGh90a, LiGh91]. Woo et al. WQG94] propem duas camadas de protocolos de sincronizao, baseadas no modelo XOCPN, uma para intramdia e outra para intermdias, as quais destinam se comunicao de informaes multimdias pr orquestradas. O presente artigo apresenta a implementao de um servio de sincronizao multimdia, ....

....de dados armazenados so dispositivos que armazenam os dados capturados. Estas fontes podem gerar dados a taxas diferentes da qual foram capturados e ou sero apresentados. Com isto, o sistema possui uma flexibilidade maior para planejar os tempos nos quais os dados sero comunicados para a aplicao [LiGh91]. Um exemplo deste tipo de fonte o CD ROM. Os dados multimdias podem ser classificados em dois tipos: Dados iscronos, ou contnuos, referem se aos dados gerados a partir da captura de um evento que se sucede continuamente. A seqncia de informaes inerente ao evento capturada uma taxa constante. ....

[Article contains additional citation context not shown here]

Little, T.D.C. e Ghafoor, A., "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE J. Select. Areas in Commun., vol. 9, n 9, pp. 1368-82, dezembro de 1991.

....na identificao das relaes causais entre unidades de informao de um ou vrios fluxos. Qazi et al. QWG93] propem uma tcnica para comunicao de objetos multimdias distribudos utilizando um modelo estendido (XOCPN) da rede de Petri temporizada para composio de objetos, proposto por Little Ghafoor [LiGh90a, LiGh91]. Woo et al. WQG94] definem camadas de protocolos para sincronizao intra e intermdias, baseadas no modelo XOCPN, as quais destinam se comunicao de informaes multimdias pr orquestradas. Este trabalho apresenta a implementao de um sistema desenvolvido no Grupo de Teleinformtica e Automao (GTA) da ....

....para atender s demandas de uma apresentao de mltiplas mdias, que envolve tarefas com atividades paralelas e seqenciais. Como cada objeto multimdia constitudo por elementos de dados relativos uma determinada mdia, a OCPN especifica as diversas relaes temporais entre objetos multimdias [LiGh91], j que ela descreve efetivamente relaes do tipo antes , depois , durante , iniciar junto , terminar junto etc. O modelo OCPN especifica, ainda, a utilizao de recursos (relacionados com os tipos de objetos, tais como udio, vdeo, texto etc) atravs dos lugares da rede Petri. As OCPNs so redes ....

[Article contains additional citation context not shown here]

Little, T.D.C. e Ghafoor, A., "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE J. Select. Areas in Commun., vol. 9, n 9, pp. 1368-82, dezembro de 1991.

....na identificao das relaes causais entre unidades de informao de um ou vrios fluxos. A tcnica proposta por Qazi et al. 11] para comunicao de objetos multimdias distribudos, utiliza um modelo estendido (XOCPN) da rede de Petri temporizada para composio de objetos, proposto por Little Ghafoor [12,13]. Woo et al. 2] propem duas camadas de protocolos de sincronizao, baseadas no modelo XOCPN, uma para intramdia e outra para intermdias, as quais destinam se comunicao de informaes multimdias pr orquestradas. A proposta deste artigo apresentar um dos trabalhos desenvolvidos no Grupo de ....

....representao de eventos concorrentes e assncronos. A OCPN incorpora, modifica e acrescenta caractersticas a estes modelos. Um objeto multimdia constitudo por elementos de dados relativos uma determinada mdia. Atravs da OCPN, possvel especificar as diversas relaes temporais entre objetos multimdias [13], j que ela descreve efetivamente relaes do tipo antes , depois , durante , iniciar junto , terminar junto etc. O modelo OCPN especifica, ainda, a utilizao de recursos (relacionados com os tipos de objetos, tais como udio, vdeo, texto etc) pelos lugares da rede Petri. As OCPNs so ....

[Article contains additional citation context not shown here]

Little, T.D.C. e Ghafoor, A., "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE J. Select. Areas Commun., vol. 9, n 9, pp. 1368-82, dezembro de 1991.

....playout continuity by buffering massive packets at receiving end systems [7] or delaying the playout time of the first packet received [3,8] These methods have been shown to be feasible but at the expense of a drastic increase in playout delay. On the other hand, dynamic feedback based methods [5,9] perform intramedia synchronization through adjusting the source generation rate by means of sending feedbacks from receiving end systems. These methods are effective, however, unviable for most live source applications. Unlike the two classes of methods described above, dynamic delay based ....

T. Little and A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services," IEEE Journal on Selected Areas in Communications, vol. 9, no. 9, Dec. 1991, pp. 1368-1382.

....paper. We are not aware of any prior work on object scheduling, playout control or synchronization that has analyzed the problem using an earliness lateness penalization framework. But, a significant amount of work has been done for specifying inter media synchronization and temporal requirements [24, 25]. The most well known methods [Blakowski et.al. in 24] for this being interval based specification, axes based methods (e.g. by using global timers, virtual axes) control flow based specification (using reference points or petri nets) and event and script based methods. The issues addressed in ....

....stated above can also be viewed as a method to smooth out burstiness in traffic. It is likely that by doing optimal scheduling taking into account both lateness and earliness penalties, that potentially less buffer space will be required to remove jitter. 3. In an earlier work, Little and Ghafoor [25] had suggested an algorithm for retrieval and delivery of multimedia data. The primary focus was on retrieval of objects residing on a single server. The temporal requirements among objects were specified using object composition petri nets (OCPNs) Given a temporal specification they come up with ....

[Article contains additional citation context not shown here]

T.D.C. Little and A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services," IEEE Journal on Selected Areas in Communications, pp. 1368-1382, Vol. 9, No. 9, 1991.

.... and Wei Zhao Department of Computer Science Texas A M University College Station, Texas 77843 3112 Amit Kumar Network Hardware Division IBM Corporation Research Triangle Park, NC 27709 1 INTRODUCTION The development of high speed networks makes multimedia communication services possible [13, 15, 21]. Such services include teleconferencing, video telephony, video on demand, distant learning, telemedicine, etc. In these applications, a bandwidth much higher than that of many traditional legacy local area networks is required. In addition, timely transmission of messages is required[14, 22] If ....

T. Little and A. Ghafoor. Multimedia synchronization protocols for broadband integrated services. IEEE Journal on Selected Areas in Communications, SAC-9(9):1368--1382, December 1991.

....scheme to facilitate storage and retrieval of media elements based on the Object Composition Petri Net (OCPN) model. An integrated model based on OCPN for the problems of low level and highlevel synchronization and object management in a network environment was also studied [LG90a, LG91b, LG91a] However, it was assumed that the database contains only consistent temporal relationship specification, i.e. the timing values for the object presentation durations are consistent with all the user specified temporal relationships. For example, two temporal intervals specified to begin and end ....

T.D.C. Little and A. Ghafoor. Multimedia synchronization protocols for broadband integrated services. to appear in IEEE Journal on Selected Areas in Communications, 1991.

....are extremely simple to implement but the buffer needed to guarantee the synchronization requirements may be so big that it causes unacceptable delays. The second kind of technique uses mechanisms which reshape the probability density function (pdf) of the delay jitter at the destination site [14 18] by varying the information unit retrieval times at the source site. In this paper we compare the use of these two techniques; in particular, as far as the latter technique is concerned, an extension of the one presented in [17] is used. Comparison between the above two techniques is made by ....

T. D. C. Little, A. Ghafoor: "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE Journal on Selec. Areas in Comm., vol. 9, No. 9, December 1991. 18

....using the PLUS protocol and the experimental evaluation. Finally, in Section 5, concluding remarks are made. 2 Related Adaptation Schemes Different approaches have been suggested to be adaptive towards congestion. The schemes can be divided into a group which tries to reduce the network delay [13, 10] and a group which aims at adjusting the transmission behavior of the non congestion controled UDP protocol in a TCP similar fashion [2, 11, 9] In the following we present a brief summary of advantages and disadvantages of these schemes. 2 TIME EVENTS event n ns interval n start time=s ....

Thomas D.C. Little and Arif Ghafoor. Multimedia Synchronization Protocols for Broadband Integrated Services. IEEE Journal on Selected Arears in Communications, 9(9):1368--1381, December 1991.

....time. This would require some buffering at the receiving site. At the receiving site, however, more work is needed to assure the synchronization of the streams (for example, video frame must match the audio frame in a motion picture) Issues related to multimedia synchronization are reported in [1,2,3,4,5]. A large number of commercial organizations as well as universities use some type of local area network environment and they have two options for adding multimedia capabilities. One is to attempt to utilize their existing networks by adding some devices and or software in order to transmit ....

T. D. C. Little and A Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services," IEEE Journal on Selected Areas in Communication, 1991, 13681482.

....Figure 1: DSD Adaptation. flow analysis is provided. In [22] feedbacks were used to design robust resource management over the network. Different approaches have been suggested to be adaptive towards congestion. The schemes can be divided into a group which tries to reduce the network delay [29, 18] and a group which aims at adjusting the transmission behavior of the non congestion controlled UDP protocol in a TCP similar fashion [5, 19, 15] The following presents a brief summary of advantages and disadvantages of these schemes. ffl Floyd and Ott [10, 32] propose a scheme which is a part ....

Thomas D.C. Little and Arif Ghafoor. Multimedia Synchronization Protocols for Broadband Integrated Services. IEEE Journal on Selected Arears in Communications, 9(9):1368--1381, December 1991.

....BW 28.8 Data Transfer Rate (Kb s) Time (sec) 120 10 40 70 20 Pastorale Capitol Simthsonian 1 Narration 2 Simthsonian 2 Narration 3 Narration 1 Available BW Figure 2: Tour of Washington D.C. to be supported will vary over time dependingon the structure of the presentation [16, 17]. Tables 1 and 2 show the data consumption rate for the above two presentation examples. The variable data rate makes the task of efficient allocation of resources in shared components more complex. One simple resource allocation policy for applications with variable bandwidth requirement is to ....

....of objects, dedicated vs shared resources on these paths, and available buffer and BW resources in each system component. Note that BW variability in a presentation can come from two sources: variations in compression ratio of a stream [19, 9] and composition of different multimedia objects [16, 17, 18]. The JINSIL system deals with the second case, and can use the solutions proposed in [19, 9] for dealing with changing compression ratios. The main focus of this paper are the scheduling and resource allocation issues addressed by JINSIL in an environment with shared components. First, at each ....

[Article contains additional citation context not shown here]

T. D. C. Little and A. Ghafoor, " Multimedia synchronization protocols for broadbandintegrated services", IEEE JSAC, 9(9):1368--1382, December 1991.

....applications and multimedia services [6, 29, 80] These networks would make available the raw bandwidth necessary for such applications. Furthermore, such networks would be able to satisfy the strict quality of service requirements (e.g. minimal delay, jitter, loss) of multimedia applications [43, 46]. In a multimedia application the video component will have the largest bandwidth requirement. For example, one second of uncompressed video, with 640 Theta 480 pixels per frame, 24 bits of colour information per pixel (RGB standard) and a display rate of 30 frames per second (NTSC standard) ....

.... with mutual dependencies (e.g. video and the corresponding audio information in a video clip) Different applications have different synchronization needs and the synchronization time may vary from less than 50 msecs for lip synchronization to several hundred msecs for text and image overlay [43]. Out of the principal media (video, voice and data) in a multimedia application, the video component of a multimedia application has the most stringent service re 10 quirements. Thus, there is a need to consider the service requirements of the video component in detail. ffl Bandwidth: The ....

T. Little and A. Ghafoor, "Multimedia synchronization protocols for broadband integrated services", IEEE Journal on Selected Areas in Communications, Vol. 9, No. 9, pp. 1368-1381, December 1991.

....implementation of synchronization protocols than the higher level 11 The hierarchical decomposition of synchronization specifications may be useful in constructing programming models of complex multimedia applications, say, for verification purposes. petrinet based specifications employed in [18]. We now analyze how the ordering relations, as specified in QOS transp , can be used by the underlying protocols to generate data play out schedules. 6 Execution frameworks for synchronization protocols The parameters specified in QOS transp may be used to: i) generate a specification of the ....

.... a flexible specification of QOS transp from application level synchronization requirements and using the QOS transp in various components of the MCS (such as generating delay bounds for channels see also [19] The work close to our paper is the object composition petrinet model proposed in [18] which deals with higher level requirements as to how temporal relationships among multimedia data streams can be specified and how these relationships may be enforced by a synchronization protocol to generate data play out schedules. Likewise, the partial order transport service model ....

T. D. C. Little and A. Ghafoor. Multimedia Synchronization Protocols for Broadband Integrated Services. In IEEE Journal on Selected Areas in Communications, Vol.SAC-9, No.9, Dec. 1991.

.... regarding the timing specification, i.e. the synchronization, of multimedia objects for the purpose of presentation can be found in [1, 9, 12, 15, 16, 25] The synchronization and integration of multimedia objects in the communication network layer of multimedia systems has also been discussed in [15, 16, 17, 18, 25]. In order to satisfy the requirements, for example real time delivery, of some multimedia applications, the quality of service (QOS) support of the communication network and of the operating systems has been an important research topic [2, 17, 19, 20, 23] The quality of service is also ....

.... systems has also been discussed in [15, 16, 17, 18, 25] In order to satisfy the requirements, for example real time delivery, of some multimedia applications, the quality of service (QOS) support of the communication network and of the operating systems has been an important research topic [2, 17, 19, 20, 23]. The quality of service is also considered in the presentation layer of the multimedia systems [8, 24] In our view, there are three different multimedia schemas in the DMS. The Multimedia Static Schema (MSS) specifies the static structure of the composite multimedia objects, including the ....

Little TDC, Ghafoor A (1991) Multimedia Synchronization Protocols for Broadband Integrated Services. IEEE JSAC 9(9):1368-1381

....Text Time Image Video Audio Text Time Image Video Audio Text Time Image Video Audio Text Time Image Video Audio Text nation node. The actual delay experienced by every data packet cannot exceed the preset end to end delay for the network connection and a global accurate clock is required. In [8], Little et al. propose computing schedules before transmitting the data packets. The multimedia tra#c runs according to the schedule to reach the destination in time for the presentation. However, because of the random network disturbance introduced by the networks, scheduling and predicting the ....

T.Little and A.Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services ", IEEE JSAC, vol.9, no.9, Dec.1991.

....between the submitted and the delivered streams, starting when delivering the first information unit of the stream. 6 Application of RT LOTOS to the design of multimedia protocols The purpose of this section is to show how RTLOTOS may be used for specifying and validating multimedia protocols [LG91, EPD94]. The test case considered here is an intra stream synchronization mechanism. The design approach relies on the identification and specification of generic and reusable specification building blocks which are then combined to constitute the global specification of the mechanism within some ....

.... a variable positive drift of the receiver clock uniformally distributed in interval [0; 0:5 ] 7 Conclusion The paper has presented RT LOTOS, its tool environment RTL and has shown how this new formal description technique may be useful for formally designing multimedia protocols and algorithms [LG91]. Main advantages of using RT LOTOS with respect to other approaches can be summarized in the following points: ffl RT LOTOS provides different important features for expressing time dependent behaviors, like the concepts of delay, latency, temporal offering, time measurement, temporal violation ....

T.D.C. Little and A. Ghafoor. Multimedia synchronization protocols for broadband integrated services. IEEE Journal on Selected Areas in Communications, 9(9), December 1991.

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T. D. C. Little and A. Ghafoor, "Multimedia synchronization protocols for broad-band integrated services," IEEE Trans. Commun., vol. 9, pp. 1368--1382, Dec. 1991.

....management protocols are limited by the propagation delays involved in coordinating the sharing of link resources. Most enterprise multimedia applications and services are expected to use some form of pre orchestrated information stored at various servers interconnected over broadband networks [3, 4]. Retrieval and communication of multimedia data imposes diverse performance and reliability characteristics, on the underlying communication infrastructure. For example, while transmitting video and audio data streams, network delays must be bounded to maintain inter stream and intra stream ....

....multimedia data imposes diverse performance and reliability characteristics, on the underlying communication infrastructure. For example, while transmitting video and audio data streams, network delays must be bounded to maintain inter stream and intra stream temporal synchronization requirements [3]. Inter stream synchronization deals with the synchronized play out of related streams, whereas intra stream is required for the continuous presentation of each stream. Multimedia information, in general, has a highly time varying bandwidth requirement. To achieve proper synchronization, without ....

T.D.C. Little and A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE Journal on Selected Areas in Communications, vol. 9, pp. 1368--1382, December 1991. 24

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T.D.C. Little and A. Ghafoor, "Multimedia Synchronization Protocols for Broadband Integrated Services, " IEEE JSAC, Dec. 1991?

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T. D. C. Little, A. Ghafoor: "Multimedia Synchronization Protocols for Broadband Integrated Services", IEEE J. Select. Areas Commun., vol. 9, no. 9, December 1991, pp. 1368-1382

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T. Little and A. Ghafoor. Multimedia synchronization protocols for broadband integrated services. IEEE Journal on Selected Areas in Communication, 9(9):1368--1382, December 1991.

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