• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.16-24
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• 2000

In the distributed multimedia document system, media objects distributed over a computer network are retrieved from their sources and presented to users according to specifed temporal relations. For effective presentation, synchronization have to he supported. Furthermore, presentation in distributed environments is influenced by network band with and delay, so they have to be considered for synchronization. This paper propose a distributed multimedia presentation model that supports synchronization effectively. In this model, when media objects are transfered from servers to a client, network situation and resources are monitored and thus a feedback message for change of them is sent to sever. Then, the sever adjusts the data sending rate to control synchronization.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1860-1875
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• 2013

In this paper, we present a comparative performance evaluation of the sampling frequency synchronization method that eliminates the initial sampling frequency offset (SFO) to reduce the overall synchronization time in Digital Radio Mondiale (DRM) receivers. To satisfy the advanced synchronization performance requirements of DRM receivers, we introduce the conventional DRM synchronization method (Method 1) and another method (Method 2), which does not perform the initial sampling frequency synchronization in the conventional synchronization method (both methods are mentioned later in this paper). To demonstrate the effectiveness of the performance evaluation, analytical expressions for frame detection are derived and simulations are provided. Based on the simulations and numerical analysis, our result shows that Method 2, with a negligible performance loss, is robust to the effects of the initial sampling frequency synchronization even if SFO is present in the DRM signal. In addition, we verify that the inter-cell differential correlation used between reference cells is robust to the effect of the initial SFO.

• Journal of Korea Multimedia Society
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• v.8 no.2
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• pp.279-286
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• 2005

As the mobile environment has been generalized, data synchronization with mobile devices or mobile device and PC/server is required. To deal with the problem, the consortium was established by the companies, such as Motorola, Ericsson, and Nokia, and released SyncML(Synchronization Markup Language) as a standard of industrial area for interoperating with data synchronization and various transmission protocol. But, in synchronization process, when more than two clients requested data synchronization, data conflict can be happened. This paper studies the various conflict reasons that can happen in data synchronization processes and groups them systematically Through the analyzed information, we compose the Change Log Information(CLI) that can keep track of the chased information about synchronization. And we suggest an operation policy using CLI. Finally, we design an algorithm and adapt the policy as a method for the safety and consistency of data.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1153-1162
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• 2005

In this paper, we developed an XML Document Data Synchronization System for java(XDS4j) based on both SyncML(Synchronization Markup Language) framework Sync4j and embedded database system Berkeley DB XML. Because most existing data synchronization systems are based on file systems, data synchronization times at Fast Sync in those systems are very delayed. In the XDS4j, however, XML documents data produced at SyncML client and SyncML server are managed by embedded database system, and also synchronization time at Fast Sync is reduced because only partial elements are accessed by applying to XPath.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1159-1166
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• 2004

This paper describes a multimedia synchronization model based on the MPEG-4(Moving Picture Expert Group) system. It defines and modifies new nodes for representing temporal relationships between media objects in the BIFS(Binary Format for Scene) of MPEG-4 system which Integrates, manages and transfers multimedia objects such as audio, video, image, etc. The relationships are represented by using a multimedia temporal model during the start, play and delay time interval. In addition, we illustrate a multimedia authoring system that includes the Interface used for defining the temporal relationships. Differently from several contentional tools generally appropriate for professional users who can edit the BIFS nodes of themselves, the system provides end-users with the function that can define the temporal relationships of multimedia objects directly in the interface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5512-5517
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• 2012

In this paper we suggest multimedia synchronization model that is based on the Petri-net and services desirable quality of service requirement. Proposed model applies variable buffer which can be allowed, and then it presents high quality of service and real time characteristics. This paper decreases the data loss resulted from variation of delay time and from loss time of media-data by means of applying delay jitter in order to deal with synchronization interval adjustment. Plus, the mechanism adaptively manages the waiting time of smoothing buffer, which leads to minimize the gap from the variation of delay time. The proposed paper is suitable to the system which requires the guarantee of high quality of service and mechanism improves quality of services such as decrease of loss rate, increase of playout rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.584-589
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• 2010

In this paper we suggest multimedia synchronization model that is based on the Petri-net and services desirable quality of service requirement. Proposed model applies variable buffer which can be allowed, and then it presents high quality of service and real time characteristics. In this paper we expend Petri-net and propose new multimedia synchronization specification model in PBMSM and apply two analysis method of Petri-net to prove our model suggested. We compared with other models and showed high QoS.

• Journal of Korea Multimedia Society
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• v.19 no.10
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• pp.1808-1815
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• 2016

TPSN(Timing-sync Protocol for Sensor Networks), the representative of time synchronization protocol, has been already developed to provide time synchronization among nodes in wireless sensor networks. Even though the TPSN's method has been referenced by so many other time synchronization schemes for resource-constrained networks like wireless sensor networks or low power personal area networks, it has some inefficiency in terms of power consumption and network-wide synchronization time (or called convergence time). The main reason is that each node in TPSN needs waiting delay to solve the collision problem due to simultaneous transmission among competing nodes, which causes more power consumption and longer network convergence time for a network-wide synchronization. In this paper an improved scheme is proposed by changing message exchange method among nodes. The proposed scheme not only shortens network-wide synchronization time, but also reduce collision traffic which lead to needless power consumption. The proposed scheme's performance has been evaluated and compared with an original scheme by simulation. The results are shown to be better than the original algorithm used in TPSN.

• The Transactions of the Korea Information Processing Society
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• v.4 no.9
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• pp.2208-2220
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• 1997

This paper presents a distributed multimedia synchronization algorithm that supports both intramedia and intermedia synchronizations. The intramedia synchronization is achieved by media scaling techniques, and the intermedia synchronization is achieved by variable service rates. We compute the check period between master media's and slave media's relative time stamps for intermedia synchronization. We also evaluate our algorithm through simulations. Simulation results show that our algorithm performs well in both intramedia and intermedia synchronizations.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.31-43
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• 1996

In this paper, we analyze the delay characteristics of the multimdedia traffic in B-ISDN, and propose a weighted variable-size window estimator considering the QoS characteristics of the media and the variable delay characteristics of the networks, and present a delay estimator-based synchronization protocol for the efficient synchronization in ATM-based B-ISDN. The proposed estimator assigns a high weight value to recent cells arrived in the receiver, and suitably adjusts window size in order to efficiently adapt to delay variation by the prameter to detect the delay variation of the networks. The proposed synchronization protocol estimates end-to-end delay by the weighted variable-size window estimator, and dynamically schedules th evirtual channel of the transmitter to playout multimedia data on time in the receiver. Also, we evaluate the performance of the delay estimator, which is the most importnat functional element in our proposed synchronization protocol, by the simulation and analyze the results of the simulation.