• Journal of Advanced Navigation Technology
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• v.15 no.3
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• pp.364-371
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• 2011

In P2P distribution mobile networks, QoS of streaming media services are under heavy influence from overheads such as congestion, latency, and interference. The problem is further complicated by the fact that the popularity of media objects changes over time. This paper proposes a new FSMS+ (Fuzzy Similarity-based Multi-level Streaming Scheme) which minimizes performance degradation of streaming services due to overhead. We then utilize fuzzy similarity-based relevance that can dynamically stream the streaming media object with minimum overhead. The simulation result showed that the proposed scheme has better performance in retransmission rate, congestion control rate and latency rate than the other existing methods of distance method, DC (disk caching) method, and prefix method.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2797-2808
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• 1998

Multimedia scenario database system is a read-only multimedia-on-demand system which transfers scenarios representing the display ordering of multimedia objects. A scenario is a graph of multimedia objects and it contains spatial, temporal and contextual information of multimedia data. By structuring multimedia objects as a scenario, it is possible to enforce their display order based on their context. Furthermore, it can provide multiple display paths as well as the sharing of objects between different scenarios. As a result, the multimedia scenario database system can perform the pre-scheduling of multimedia objects, which makes it possible to reorder the transmission order of objects in a scenario. Consequently, the overall system resource such as data buffer and network bandwidth can be highly utilized. In this paper, we discuss the requirements of structuring a scenario to design a scenario database that stores and manages multimedia scenario. Furthermore, we devise and analyze several scheduling policies based on the reordering mechanism for the objects in a scenario.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.43-53
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• 2008

Hyper text transfer protocol (HTTP) over transmission control protocol (TCP) is currently used to transfer objects in the Internet. Stream control transmission protocol (SCTP), an alternative to TCP, which allows for independent delivery among streams, and can thus reduce the mean response delay of web object. We present an analytical model to find the mean response delay for HTTP over SCTP, therefore, estimate the effectiveness of SCTP over TCP. Typical TCP delay models assume the wired environment. On the contrary, the proposed model in this paper assumes the multiple packet losses and wireless environment where fast retransmission is not possible due to small window. The estimated mean response time can be used the benchmark to meet quality of service (QoS) at end-user. We validate the accuracy of our model using experiments. It is shown that the differences between the results from model and those from experimental are very small below 6 % on average. We also find that the mean response delay for HTTP over SCTP is less than that for HTTP over TCP.

• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.1025-1034
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• 2008

In this paper, we developed GridGML for efficiently supplying a GML and visualizing the map with partitioning map and caching method to a mobile device. In order to overcome the weighting of a file, which is the biggest weakness of a GML, GridGML extracts only the most necessary parts for the visualization of the map among GML attributes, and makes the file light as a class instance by applying an offset value. GridGML manages a partition based on the visualization area of a mobile device to visualize the map to a mobile device in real time, and transmits the partition area by serializing it for the benefit of transmission. Also, the received partition area is compounded in a mobile device and is visualized by being partitioned again as four visible areas based on the display of a mobile device. Then, the area is managed by applying a caching algorithm in consideration of repetitiveness for a received map for the efficient operation of resources. Also, in order to prevent the delay in transmission time as regards the instance density area of the map, an adaptive map partition mechanism is proposed for maintaining the transmission time uniformly.

• Journal of KIISE
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• v.43 no.5
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• pp.606-612
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• 2016

The multi-view video service based on the DASH(Dynamic Adaptive Streaming over HTTP) switches the viewpoint or object which is selected by the user among the multiple video streams captured by multiple cameras. However, the problem is that the conventional DASH-based multi-view video service takes a long time to switch the viewpoint. The reason is that the conventional scheme switches to the new video stream after consuming all buffered segments of the previous video stream. In this paper, we propose a video streaming scheme for minimizing the viewpoint switching delay in the DASH-based multi-view video service. In order to minimize the viewpoint switching delay, the proposed scheme configures the video streams by controlling the GoP (Group of Pictures) size and controls the client buffer based on bandwidth estimation and playback buffer occupancy. Through the experimental results, we prove that the proposed scheme reduces the viewpoint switching delay.

• Journal of Korea Multimedia Society
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• v.4 no.4
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• pp.297-305
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• 2001

Recently advances in high-speed networks and multimedia computer technologies allow new types of multimedia applications to manipulate large volumes of multimedia data. However, in the real time and/or the heterogeneous data transmissions, there are many difficulties such as network transmission delay, the implementation difficulties, and so on. To solve these problems, in this paper, we extend the method of the multimedia service design which is proposed by OMG. To do this, we suggest an efficient real time audio/video stream framework, called Smart Explorer, based un CORBA and JMF Java Media API. And we separate the transmission path of control data from that of media data and use RTP/RTCP protocol for efficient real time audio/video transmission. Also we show the appropriate implementation of the audio/video stream system based on our suggested framework Smart Explorer. In the future, we expect our audio/video stream system to be applied to the real time communication software such as broadcasting, distance learning, and video conferencing.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.787-796
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• 1995

In this paper, a mechanism to enhance the utilization of the tertiary storage devices such as optical disk, digital tape and so on is proposed. For this purpose, we suggest a storage structure with a CD-ROM and multiple disk and design an efficient mechanism to represent the continuous media stored in CD-ROM. The continuous media storage structure proposed in this pater can enhanced the retrieval capability of information by sending data using a shared bus with high bandwidth. And a continuous media representation mechanism not only can reduce the discontinuity of representation using parallel operation of fetch and representation but also minimize the variance of service time and the missing ratio of re-reference requirement by residing frequently accessed object on the disk.

• 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 Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1253-1258
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• 2006

In the mobile vector map service environments, there are problems like as terminal resource shortage and transmission delay for the characteristics of large spatial data. For the normal mobile vector map services, some techniques are required to overcome the problems. Spatial data compression approach is one of the techniques to reduce the bandwidth and the waiting time at clients. However it also must be considered that the effect on total efficiency caused by the overhead of compression and restoration time. This thesis proposes two spatial data compression techniques. First approach is to get relative coordinates to first coordinate of each object. The other approach is to compute client coordinates before transmission. Through the implementation and experiments, proposed techniques are evaluated the compression effects and efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.314-324
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• 2004

Recently, high-speed internet subscribers have grown continuously, and reached up to 10 millions. But existing network management that is responsible only for user access is confronted with many difficulties, since user access network(xDSL, Cable, B-WILL, and so on) has diversified and value added wired/wireless contents service has developed. In this paper propose the Agent based Inter Networking platform as object-oriented hierarchical system that can provide various service such as access QoS(Quality of Service), customized application service and security service according to user on demand. This system has divided into two parts(user agent and agent management system ＆ local and central management systems). Management system periodically receive status information such as bandwidth, download speed, delay, current service, and so on, and process them, then build a policy based on processed information. According to personal user profile that is generated by this policy, the customized service can be provided for users. And This system adopt the object-oriented modeling in case that system migration and integration, and implement a system that is robust and stable for security through hierarchical server system.