• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1303-1309
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• 2012

In this paper, we propose a handover scheme for seamless mobile multicast service in next generation access networks. For this, we drew optimum handover scheme when applying MIP(mobile IP), FMIP(Fast MIP), HMIP(Heterogeneous MIP), PMIP(Proxy MIP) to XG-PON1. And, we analyze handover scheme for seamless mobile multicast service in XG-PON1. The prosed handover scheme remove tunnel convergence and reduces handover delay, packet delivery cost.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.905-912
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• 2006

Depending on the location of the rendezvous point (RP), the network efficiency is determined in the core based tree (CBT) or protocol independent multicast-sparse mode (PIM-5M) multicasting protocol to provide the multicast services based on the shared tree. In this paper, a new algorithm to allocate the RP using the estimated values of the total cost and the size(number of entries) of the routing tables is proposed for efficiently controlling the cost and the number of routing table entries. The numerical results show that the proposed algorithm reduces the total cost in 5.37%, and the size of routing tables in 13.35% as compared to the previous algorithm.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.569-572
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• 2008

I proposed wireless ordering system using Qt embedded. This system will make the good use of real life applications and make fit for practical use. I embodied data input, transfer, gathering and back-transfer on wireless network using TCP/IP protocol on QSocket provided by Qt. Server environment is Linux 9.0 and gcc-2.95.3 on PC, and three target-boards consist PXA255 processor with wireless-LAN card which communicate through wireless access pointer. Software tools on target-board are gcc, tmake, qt-X11, qt-embedded and etc. I designed touch-screen interface for user convenience.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.542-545
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• 2006

In recent years, RFID is widely used in Industrial applications including factory, material flow, logistics and defense areas. In this paper, we developed a RFID baseband system with ASK modulation and convolutional channel code. A commercial ASK RF module is used and its frequency range in $350\sim351MHz$ and power is 10mW and the convolution code is constraint length k=3 and rate R=1/2. The performance is measured by frame error rate and the convolutional code is very useful in performance improvement and, also we implemented the binary search algorithm as anti-collision method and we show the wave shapes whit collision occurrence. This RFID system is designed by FPGA therefore it produces result of speed-up and improvement of reliability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.131-138
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• 2007

Plain old Web Services came true a services integration with use the XML that will be able to define a platform-independent document format in basic document format. Hut, the XML document decreases the efficiency of the whole application program with connects frequently in relatively slow communication media like network environment, embedded system or use the resource limited small-sized instrument like mobile. In this paper, we implemented the algorism of Fast Infoset, which can convert XML into Fast XML using the Fast Inoset method and PER encoding rules in ASN.1 and constructs Test Bed. Also, it is compared with the existing pure XML message method in difference of process performance after encoding SOAP messages of XML basis when constructing web service.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.295-302
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• 2016

Many countries, especially ICT powers, are supporting IoT-based technology at a national level and this technology is actively being researched in the businesses and research institutes in an aim to develop technology and create an ecosystem. Roads in the Seoul city are building public facilities based on IoT to provide various services and conveniences for the users. However, for the full-fledged introduction and development of IoT, there are many cases where infringement on security and privacy and threat for life and safety happen. Also, as the IoT environment includes various environment technologies such as the existing sensor network, heterogeneous communication network, and devices optimized for the IoT environment, it inherits the existing security threat and various attack techniques. This paper researches the attribute based encryption technology for safe communication in the IoT environment. The data collected from the device is transmitted utilizing the attribute based encryption and by designing the key generation protocol, grades and authorities for the device and users are identified to transmit safe messages.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.13-21
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• 2006

An mobile ad hoc network(MANET) is a collection of wireless computers (nodes), communicating among themselves over multi-hop paths, without the help of any infrastructure such as base stations or access points. Prior research in MANET has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we design and evaluate the Secure Zone Routing Protocol(T-ZRP), a secure ad hoc network routing protocol is based on the design of the hash chain. In order to support use with nodes of limited CPU processing capability, and to guard against Denial-of-Service attacks in which an attacker attempts to cause other nodes to consume excess network bandwidth or processing time, we use efficient one-way hash functions and don't use asymmetric cryptographic operations in the protocol. Proposed algorithm can safely send to data through authentication mechanism and integrity about routing establishment.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1231-1242
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• 1997

This paper deals with an IP mukticast protocol in support of host mobility. Most of the previous multicast schemes have utilized an underlying logical strucuture of network topology,in order to provide a certain degree of order and predictability.On the other hand,mobility implies that a host location relaative to the rest of the net-work changes with time;the physical connectivity of the entire network is thus modified as move.In this case.some multicast datagrams nay not delivered properly,or may delivered twice or more,to a mobile host because the destinations will keep moving whlist datagrams are dekivered with different time delay.This paper first describes the relation between host mobility and multicast, by exploring the possible interactions,and presents a multicast scheme in support of Internet host mobility.A revised scheme is then proposed to adapt the multicast semantic and to optimize the communication overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11A
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• pp.1253-1262
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• 2004

The Data Over Cable System Interface Specification (DOCSIS) protocol enables the delivery of Internet Protocol(IP) traffic over Cable TV networks with significantly higher data rates. In this paper, we assessed the performance of the DOCSIS protocol using the OPNET. The simulation can be used to predict the upstream system throughput, mean access delay and channel utilization on varying packet size and transmission stream and wid/without concatenation, and it has shown that maximum system throughput is 4.6 Mbps for channel capacity of 5.12 Mbps and packet size of 1500 bytes. The mean access delay varies depending on the offered load, and it is assumed that the offered load does not exceed the capacity of the channel. Excess offered load causes service starvation according to the assigned priority.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1048-1057
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• 2015

In this paper, we propose a fast MAS reallocation method that can avoid reservation conflicts in the DRP process of WiMedia system in real time. WiMedia MAC DRP has been developed aimed QoS support for audio and video transmission that generate traffic periodically. The size variation of the video streaming data causes DRP reservation conflicts frequently, so that DRP could not support QoS of the video streaming service which is delay-sensitive. Fast MAS reallocation method could avoid reservation conflicts in real-time analyzing reservation requests information of the other device. Our proposed method is evaluated with test sequences using the software simulation and implemented in hardware/software with the integrated WiMedia MAC/PHY system.