• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.5
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• pp.1028-1048
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• 2011

The relation of multicast transmission and directional antennas is an open problem that has been debated for a long period of time. In this paper, we propose a group-aware multicast scheme of efficient multicast communication using the directional antennas for 60GHz millimeter wave wireless networks. For this purpose, we first derive the relation among beamwidth, distance between devices and most suitable data rate in the 60GHz frequency-based wireless network. In addition, for the dynamic beamforming of multicast communication, the x and y coordinates of any point with sender device at the center is generated, and a best-chosen group is deduced based on the Euclidean distance. Then the most suitable data rate for the group is obtained using the law of cosine. Using the Standard IEEE 802.11ad MAC protocol as an example, extensive simulation results demonstrate that the proposed scheme outperforms the existing multicast communication schemes with directional antennas under different situations.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.228-231
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• 2008

For a satellite data communication, the technology of frame synchronization is widely used between a sender and a receiver. Last year, we suggested zero-loss frame synchronization [1] using pattern search and using bits threshold search algorithm that is based on SIMD technology [2,3]. This algorithm could solve both of hardware and software drawbacks, which are frame loss and low processing performance. However, this algorithm didn't optimize the processing of output data, synchronized data, which caused overhead to the memory allocation and the memory copy. Consequently, the performance of the frame synchronizer application was degraded. In this paper, we enhance previous work using a circular buffer in order to optimize the output data processing. The performance comparison with the previous algorithm shows that the enhanced proposed approach dramatically outperforms in the output data processing speed.

• International Commerce and Information Review
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• v.9 no.2
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• pp.123-140
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• 2007

This paper wants to suggest some issues on the acceptance of payment order in Electronic Funds Transfer of USA. The result can be summarized as fellows; First, originator's bank accepts a payment order when it executes the order. Secondly, beneficiary's bank accepts a payment order at the earliest of the following times: (1) when the bank pays the beneficiary as stated in Section 4A-405(a) or 4A-405(b), (2) when the bank notifies the beneficiary of receipt of the order or that the account of the beneficiary has been credited with respect to the order unless the notice indicates that the bank is rejecting the order or that funds with respect to the order may not be withdrawn or used until receipt of payment from of the order. (3) when the bank receives payment of the entire amount of the sender's order pursuant to Section 4A-403(a)(1) or 4A-403(a)(2). Lastly, the acceptance of a payment order cannot occur before the order is received by the receiving bank.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.821-831
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• 2006

In this paper we researched on the development methods and design of the B-ISDN protocol embedded Internet-Phone PBX System for the previous telephone exchange and communication. We designed the structure of the user terminal md exchange server of the Internet-Phone PBX System, defined message and data structure for call control, and designed call control message flows between sender and receiver terminal for user's communication.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.49-54
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• 2009

Synchronization between media is an important aspect in the design of multimedia streaming system. This paper proposes a precise media synchronization mechanism for digital video and audio transport over IP networks. To support synchronization between video and audio bitstreams transported over IP networks, RTP/RTCP protocol suite is usually employed. To provide a precise mechanism for media synchronization between video and audio, we suggest an efficient media synchronization algorithm based on NPT (Normal Play Time) which can be derivable from the timestamp information in the header part of RTP packet generated for the transport of video and audio streams. With the proposed method, we do not need to send and process any RTCP SR (sender report) packet which is required for conventional media synchronization scheme, and accordingly could reduce the number of required UDP ports and the amount of control traffic injected into the network.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.96-97
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• 2011

Heterogeneity in different Health Information Systems (HIS) processes persists to be the most demanded problem to be resolved in healthcare domain. The only way to resolve this problem is to practice health standards. One of such standards is Health Level Seven (HL7), used for the communication of medical information between healthcare systems. HL7 V3 has the aim to support all healthcare workflows. It defines series of electronic messages called interactions to support healthcare workflows. These interactions are part of the Interaction Model. Different healthcare organizations can conform to different process workflows based on their requirements. The heterogeneity in workflows results in communication blockade between sender and receiver healthcare organizations. We propose Interaction Ontology in order to cater the heterogeneity in workflows and provide process interoperability.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.205-209
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• 2007

인터넷과 핸드폰의 보급으로 컴퓨터 사용자가 전자 메일 통한 통신 방법이 활발하다. 전자 메일의 사용은 개인적인 일은 물론 기업 사무, 광고 메일, 뉴스, 광고 메일 등 폭넓게 이용되고 있다. 전자 메일 클라이언트에 자연언어처리의 고급 기능의 탑재와 컴퓨터 바이러스 혹은 스팸 메일을 방지하는 고기능이 임베디드 되어야 한다. 자연언어처리 기법을 이용하여 전자 메일의 내용에 포함된 작성자의 "즐거움", "성남", "슬픔"등 인간의 복잡한 감정 표현을 송신과 수신 프로세서에서 이해시키며, 전자 메일을 송신하기 전문서의 내용 중에 불쾌한 표현을 제거하여 문서 교정을 독려하는 지능적인 전자 메일 클라이언트 시스템을 설계하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1604-1617
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• 2014

This paper proposes RIX-MAC (Receiver-Initiated X-MAC), a new energy-efficient MAC protocol based on an asynchronous duty cycling. RIX-MAC improves energy efficiency through utilizing short preambles and adopting the receiver-initiated approach, where RIX-MAC minimizes sender nodes' energy consumption by enabling transmitters to predict receiver nodes' wake-up times. It also reduces receiver nodes' energy consumption by decreasing the number of control frames. We use the network simulator to evaluate RIX-MAC's performance. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a remarkable improvement in energy-efficiency and end-to-end delay.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.625-627
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• 2001

기존의 멀티캐스트 프로토콜은 수신자가 주체가 되어 그룹에 가입/탈퇴하여 송신자는 그룹을 관리하기 힘든 구조로 되어 있으며, 전송 계층으로 WP를 사용하여 신뢰성이 보장되지 않는다. 본 논문은 교육 시스템과 같이 송신자(서버) 중심의 멀티미디어 데이터 통신이 이루어지는 시스템을 위해서 송신자 중심의 그룹 관리와 통신 신뢰성을 제공하는 멀티캐스트 미들웨어를 설계 구현한다.

• Journal of the Korea Safety Management & Science
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• v.9 no.6
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• pp.137-146
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• 2007

The objective of this paper is to study the establishing system of truck collaboration and to reduce traffic cost for participating transportation enterprises. The system of truck collaboration can enhance the transport efficiency and to reduce traffic cost without new investment for trucks and equipments. The type of truck collaboration should be enumerated (1) the system of head and branch base (2) the system of central terminal (3) the system of separating collection and delivery for cargo (4) the system of cooperating cargo order and truck allocation. The efficiency of truck collaboration is possible to be realized for transportation enterprises, receiver and sender of cargo.