• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.351.1-355
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• 1998

Network-based real-time multimedia applications require guaranteed performances of communication service. Also according to increased bandwidth and processing performance in the future high speed networks, it is possible to make multimedia real-time applications such as distributed real-time applications including video conference, medical imaging, and video education. These applications have characteristics of stringent performance requirements in terms of delay, delay jitter and maximum loss rate. This paper proposes a new delay control for Broadband networks with FCFS queueing. The delay control provides an alternative solution to a current problem in real-time communication; traffic distortion, which makes it difficult to meet such real-time requirements. In simulations, it shows that the proposed delay control can guarantee local and end-to-end delay.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.37-44
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• 2016

It is important that using of efficient radio resource because of deficiency spectrum problem, so that related to this problem many researches are have proceeded. To solve this problem, Cognitive Radio(CR) was suggested. The channels are allocated to the secondary users when the primary users don't use the channels, and unfairness of secondary users can be serious problem and channel quality of multichannel can be different due to the different traffic pattern of primary users. In this paper, we propose MAC prtocol both of the user's fairness and channel quality in CR networks. Simulation results show the comparison with CR MAC protocols.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.70-74
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• 2008

We are using COS to purpose blocking the excess current and to protect the transformer. But the fuse of COS is melt due to the overload if the excess current flows and it destroy an air severing relations to clear as strong arc happens. Such phenomenon induces an impact ambient noise and it gives the circumstance area resident or pedestrian the fear. Thus, We are the actual circumstances which an ambient noise countermeasure establishment have desired urgently. In this study, we grasp the characteristic of an impact ambient noise which a COS fuse happens the melting and study the method to reduce an impact ambient noise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3654-3659
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• 2011

The MAC protocol of HiperLAN/2 is based on TDMA/TDD. The radio channels are assigned by AP(Access Point) that is centrally operated. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channels. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Therefore, number of RCH should be allocated properly according to traffic. From these viewpoints, this paper proposes an advanced scheme that dynamically changed the number of RCH which is based on the number of success and collision of RR message in previous MAC frame. To prove efficiency of proposed scheme, lots of simulations are conducted and analyzed.

• IE interfaces
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• v.16 no.3
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• pp.311-321
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• 2003

We propose the improved channel assignment and management methods for an efficient use of traffic channel resource for supporting 12.2 Kbps, 64 Kbps, and 384 Kbps traffic with the different quality of service(QoS) in the radio network controller(RNC) in asynchronous IMT-2000 system. We consider two types of traffic channel block assignments for utilizing the traffic channel efficiently; the Completely Shared(CS) channel assignment and the Partially Dedicated and Partially Shared(PDPS) channel assignment. The former is that all traffic channel blocks are completely shared with all traffic types. The latter is that some traffic channel block is independently assigned to each traffic type and the other blocks are completely shared with some traffic type. We also propose the traffic channel management method which consists of the block and task management step, for efficiently assigning, releasing, and managing the channel resource. Finally, we evaluate the performance through various numerical examples when applying our proposed channel block assignment and resource management methods.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.728-732
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• 2008

GeoRSS is RSS which contains geospatial information, and it supports to supply diverse kinds of data through mash-up map service like the google map. It helps to implement efficient web service with simple java-scripts, but sometimes initial page loading takes too much time and causes heavy traffic when it includes lots of multimedia data. In this paper, we propose a splitting method of GeoRSS for fast accessing. As the result of experiments, we achieved improvement of browsing speed and reducing of initial data traffic.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.496-507
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• 2003

Rapidly increasing Internet traffic demands require IP protocol based on high quality networking technology. Accordingy, our Internet has evolved from best-effort service toward differentiated service framework so as to implement QoS as prerequisite to a series of new applications. In addition, it is forecasted that existing transport network will be reorganized into DWDM-based optical Internet sooner or later under the influence of Internet demands for higher bandwidth based on QoS. This study shows a way to an effective implementation in some aspects: QoS implementation on DWDM-based optical Internet network, control protocol, backbone network architecture and switching technology for the Next Generation Internet (NGI).

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.169-176
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• 2008

In this paper, we develop radio resource management queueing model in IEEE 802.IS networks considering both connection and packet level. In the upper level connection, we model connection admission control depending on availability of bandwidth and priority queue in each service class. In the lower level packet, we model dynamic bandwidth allocation considering threshold and availability of bandwidth in each service class simultaneously. Hierarchical model is built using an extended Petri Nets, SRN (Stochastic Reward Nets). Bandwidth utilization and normal throughput as performance index for all service classes of traffic are calculated and numerical results are obtained.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.159-169
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• 1999

Recently a firewall is being employed to protect hacking by controlling the traffics. The security services in the firewall include authentication, access control, confidentiality, integrity, and audit trail. A token is adapted for authentication to the firewall. A token has a small battery within which has restricted power capacity, This paper proposes a novel cost-effective firewall token for hacking protecting on transmission control protocol/internet protocol (TCP/IP) based network. This paper proposes a fast exponentiation method with a sparse prime that take a major operation for a public-key crypto-system and a major power consumption in the token. The proposed method uses much less amount of modular operations in exponentiation that is reduced of battery's capacity or CPU's price in the token.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.682-686
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• 2009

The MAC protocol of HiperLAN/2 is based on TDMA/TDD. The radio channels are assigned by AP(Access Point) that is centrally operated. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Therefore, number of RCH should be allocated properly according to traffic. From these viewpoint, this paper proposes an advanced scheme that dynamically changed the number of RCH which is based on the number of success and collision of RR message in previous MAC frame. To prove efficiency of proposed scheme, a lots of simulations are conducted and analyzed.