Junkyun Choi

Demonstration of Smart u-Learning System

The Smart u-Learning System is designed to provide an interactive and social learning environment that accommodates emerging devices. This demonstration will show how teachers and students can use its interactivity and social features in live lecture situations.

Segmented content delivery scheme for minimizing server cost in CDN

As the volume of video content delivered over the Internet is rapidly increasing, local CDN will be necessary, storing content in edge servers. To minimize the server cost, segmented content delivery scheme is proposed, by sending multiple HTTP GET messages with range indicating the requesting segment. This paper proposes segmented content delivery scheme to reduce server cost by combining segmented content caching and delivery scheme.

Content-based pattern matching for classification of network application

In this paper, we propose the method for classification of network application. This method uses content-based pattern matching as well as port number. Some applications do not observe well-know port number, so it needs additional work to classify those accurately. Content-based pattern matching is performed using distance point. Based on this distance point, packets are classified

An approach of multipath transmission from intelligent OLT in optical-wireless converged networks

In this paper, we propose multipath transmission mechanism from optical line terminal (OLT) in an optical wireless converged network architecture. In a scenario where the content server is far away from the terminal, in terms of distribution of traffic properly the proposed mechanism shows better performance than existing solutions.

Call admission control scheme reflecting the effect of user mobility in multimedia wireless networks

To exactly calculate performance of a call admission control (CAC) scheme requires the computational complexity because of the dimension of states in the multi-dimensional Markov chain model in multimedia wireless networks. Simple approximation method is necessary to give accurate results comparing with the exact calculation method while keeping the computational complexity low. This paper proposes new CAC method reflecting the effect of user mobility while keeping the computational complexity low.

Queueing analysis for context profile handling mechanism in Proxy Mobile IP

As the number of requiring multimedia streaming and broadcasting such as IPTV through wireless access network, to provide efficient mobility in access network can be important issue. Proxy Mobile Internet Protocol (PMIP) is aimed for network side mobility support without Mobile Node side processing. In this paper, we extended our previous work by developing mathematical analysis which contains 2 state M/M/1/C queueing model. Finally, we can extract numerical result from MAG Caching mechanism, especially, in terms of blocking probability, as arrival rate increase, which expresses whether server has heavy traffic.

Flexible Channel Allocation Algorithm for Web-based IPTV Service

As the recent tendency reports, the IPTV Service has an unlimited potential in communication market. It is true that the IPTV service will become the center of interest and will widely deploy in our life. Many service scenarios are announced for efficient IPTV service in standardization meeting. Web-based IPTV service is one of those scenarios. We can serve IPTV service through the Internet, and IPTV subscribers can connect the service using the Web browser. Here, we can see that the existing Terrestrial / Cable / Satellite TV contents can easily deliver through the Internet by integration of Web and IP data services. But, it is expected that the number of output channels to the subscribers are less than the number of input channels from existing broadcaster when existing broadcasting services are transmitted through the Internet. In general, the output channel is allocated in sequence as follow the subscribers request the contents. If high preference channel is not allocated, it results in high blocking probability. In order to solve that problem, this paper addresses flexible channel allocation algorithm which is designed to reduce the blocking probability and increase the number of channels.

The origin of coarse contrast modulation in In0.525Ga0.475As layer on InP grown by MBE at 310 °C

Abstract In the TEM plane view observation of phase separated microstructures in several regions of In 0.525 Ga 0.475 As layer grown at 310 °C by MBE on InP substrate, fine modulation is found in all the regions examined, but coarse modulation is found only in thick sections of TEM thin foils. These results strongly suggest that the coarse modulation in our sample is an artifact of thin foils which appears as a result of accommodation of the biaxial stress associated with the fine modulation.