• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.1
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• pp.97-104
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• 2006

For successfully deploying many multicast service in the mobile environment, security infrastructures must be developed that manage the keys needed to provide access control to content. In this paper, we propose two methods for designing the key management scheme for the mobile multicast environment. The proposed schemes match the key management tree to the mobile multicast environment for localizing the delivery of he rekeying messages, reducing the communication costs, and solving the handoff problem in wireless region.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.3
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• pp.44-49
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• 2009

We show the way how to design and develop the information system using Zigbee technology. First we set the protocol for zigbee tag and reader. And then we give the information system using designed system based on zigbee technology. In this paper, we use MG2455-F48 module as zigbee module.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.716-719
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• 2009

소프트웨어 업데이트를 위한 업데이트 코드 전파 기법은 매우 중요한 기술 중 하나이다. 본 논문에서는 기존에 제안한 네트워크 코딩기법을 이용한 코드 전파 기법의 문제점을 파악하고 그 문제점을 해결하기 위해 혼잡 제어 기법을 이용한 코드 전파 기법을 제안한다. 제안된 코드 전파 기법은 네트워크 코딩 기법을 적용한 코드 전파 기법의 문제점인 Broadcasting시 발생된 문제점을 해결하여 00%의 성능 향상을 보인다. 뿐만 아니라 본 논문에서 제안한 방식은 혼잡 제어의 Bottle-neck 문제점을 Broadcasting 방식에 Sector를 나누고 우선순위 방식을 이용함으로써 신뢰성있는 데이터 전송을 가능하게 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.816-817
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• 2008

본 논문은 제주 택시 텔레매틱스 시스템에 축적되고 있는 택시들의 실제 이동 히스토리 정보를 이용하여 노변-차량 네트워크를 설계하는데 필요한 통신 분석기를 구현한다. 구현된 분석기는 지도처리, 좌표변환, 거리 환산 등 기본적인 사용자 인터페이스와 함께, DSRC 프로토콜에 따르는 전송 거리 등과 같이 노변-차량 통신에 있어서의 분석에 필요한 환경인자를 설정할 수 있다. 히스토리에 포함된 이동객체 위치 정보를 기반으로 현재의 RSU 배치에 대해 연결성을 계산함은 물론 각 객체의 시간적인 이동에 따라 객체들이 RSU에 연결되는 시간과 연결이 불가능한 시간 간격 등을 측정하여 현재의 배치가 시스템의 요구사항에 부합하는지 결정할 수 있다. 결국, 본 시스템은 RSU 들간의 연결성을 실제 데이터를 기반으로 분석할 수 있도록 하여 설계자로 하여금 효율적인 RSU 배치, 연결성 예측, 추후계획 등을 가능하게 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.77-82
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• 2016

Recently, an IoT(Internet of Things) application communication protocol is standardizing for connectivity between every things on Internet. In this paper, we design and implement an indoor resource control service using IETF (Internet Engineering Task Force) CoAP (Constrained Application Protocol) based on Web. We present an indoor resource control architecture based on Web included functionalities of proxy and RD (Resource Directory) in a web server. Developed indoor resource control service supports to register low-powered and small-scale IoT nodes to web server using CoAP. This service allows users to control the indoor resources through a web browser using Web proxy with functionality of HTTP-CoAP converting.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.95-103
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• 2008

The Network Mobility (NEMO) basic support protocol extends the operation of Mobile IPv6 to provide uninterrupted Internet connectivity to the communicating nodes of mobile networks. The protocol is not efficient to offer delays in data delivery and higher overheads in the case of nested mobile networks because it uses fairly sub-optimal routing and multiple encapsulation of data packets. In this paper, our scheme combining Hierarchical Mobile IPv6 (HMIPv6) functionality and Hierarchical Prefix Delegation (HPD) protocol for IPv6, which provide more effective route optimization and reduce packet header overhead and the burden of location registration for handoff. The scheme also uses hierarchical mobile network prefix (HMNP) assignment and tree-based routing mechanism to allocate the location address of mobile network nodes (MNNs) and support micro-mobility and intra-domain data communication. The performance is evaluated using NS-2.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.597-604
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• 2002

Changing group key is necessary for the remaining members when a new member joins or a member leaves the group in multicast communications. It is required to guarantee perfect forward and backward confidentiality. Unfortunately, in large groups with frequent membership changes, key changes become the primary bottleneck for scalable group. In this paper, we propose a novel approach for providing efficient group key distribution in large and dynamic groups. Unlike existing secure multicast protocols, our protocol is scalable to large groups because both the frequency and computational overhead of re-keying is determined by the size of a subgroup instead of the size of the whole group, and offers mechanism to prevent the subgroup managers with group access control from having any access to the multicast data that are transfered by sender. It also provides security service for preserving privacy in wireless computing environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1646-1652
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• 2010

The communication in wireless sensor network is divided into several layers, because of each of them do their role, the wireless communication is possible, the MAC (Medium Access Control) layer of the one of sensor network communications layer is used to the data errors, control flow, and manage resources. Using MAC Protocol, it ensures the communication between sensor node. In this paper, highlighted the energy efficiency of the S-MAC, T-MAC protocol it emphasized the efficiency of energy by lessening the woken time of all nods effectively, transmitting and receiving the control packet on only necessary nods through use of a method that RTS packet is added to SYNC packet and making other nods sleep. On sending SYNC+RTS packet and receiving the packet, nod noticed that it wasn't necessary to be awaked on this period, would be in Sleep mode, demonstrated mathematically that energy is more effective than existing protocol, and simulated with MATLAB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1211-1218
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• 2010

OSPF is the optimized routing protocol in wired network and considered as a tactical routing protocol in wireless tactical communication network. However because it is designed basically based on wired environment, it runs inadequately in wireless tactical environment: noise and jamming signal. So, we proposed new OSPF cost function to develop active routing protocol in wireless tactical communication network. In redefined cost function, there are four parameters that are relative transmission speed, link weight, router utilization, link average BER(Bit Error Rate). These parameters reflect wireless tactical characters. Also, we remodel the option field in Hello packet. It can help user to periodically check the link state. From the simulation result, it is shown that proposed OSPF is better than OSPF in jamming situation and has accumulative delay gain with dispersion of traffic load in entire network.

• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.123-128
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• 2004

Recent advancement in RF technology and wireless communications has enabled the development of noble networks. Bluetooth that can be used in various application field is a kind of WPAN(Wireless Personal Area Network) standard that is widely known. Bluetooth enables voice and data applications to operate simultaneously. Various applications have been implemented based on standard Profiles. In this paper, we describes the development of Biuetooth network AP(Access Point) system for network connection of Bluetooth devices. Unlike headset, mouse, and keyboard, the access point should have capability to support multiple connection and stabilized network throughput. We have designed and developed the hardware system, core stack and profiles on embedded system to comply with standard specification. Our system showed compatibility and good protocol performance through testing with lots of products that is available in market.