• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.405-416
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• 2013

ZigBee is a wireless sensor network protocol recognized as a next-generation standard infrastructure for WBAN and Smart Grid. Security plays an important role in several ZigBee applications. Especially, strict membership control should be enforced when the membership is changed during the join and leave operations in ZigBee. In this paper, we investigate the security weakness of the current leave operation in ZigBee and propose a new security scheme to address it as well as its security and performance analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.73-75
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• 2007

The Ad Hoc Network Interfaces has been tremendously useful in doing capacity planning and performance prediction. However, in many real-world cases. it has found that the predicted results form a queuing analysis differ substantially from the actual observed performance. Specially, in recent years, a number of studies have demonstrated that for some environments, the traffic pattern is self-similar rather than Poisson. In this paper, we study these Clustering characteristics and the definition of standadization processes.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.449-449
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• 2004

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.719-727
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• 2016

This paper proposes a unified medium access control (MAC) design methodology and presents the implementation of the IEEE 802.11ac down-link multi-user multi-input and multi-output wireless local area network MAC using the proposed design methodology. The proposed methodology employs unified code for both network simulation and system implementation. Because the unified code closely relates these two processes, the performance of the implemented MAC system can be estimated before implementation. The MAC architecture for an access point implemented using the proposed design methodology is verified on an ARM-based platform, and it is applied to a 65 nm CMOS library.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.58
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• pp.28-37
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• 2006

전파 자원은 국가의 무형 자산으로서 자원이 한정되어 있는 반면에 이에 대한 수요가 급증하면서 전파 자원의 가치가 점점 높아지고 있다. 특히 국내의 경우 IT839 전략으로 추진 중인 WiBro(Wireless Broadband), DMB(Digital Multimedia Broadcasting), Home Network, Telematics(Telecommunication Informatics), WCDMA(Wide Code Division Multiple Access), RFID/USN(Radio Frequency Identification/Ubiquitous Sensor Network) 등 무선 주파수를 이용하는 새로운 서비스가 증가하면서 주파수 자원에 대한 중요성은 더욱 강조되고 있다. 종래의 전파 정책이 정부가 정책을 세우고 이를 관리하는 Command-and-Control 위주였다면, 향후의 전파 정책은 OpYN1020en Spectrum 정책으로 전환될 것으로 전망된다. 본 고에서는 전파 자원의 효율적인 이용을 도모하는 일반적인 CR(Cognitive Radio) 기술에 대하여 언급하고, 이를 이동성이 없는 고정 환경에 적용하기 위한 IEEE 802.22 WRAN 시스템의 물리계층 전송 규격 사양, 프레임구조 및 현재 논의되고 있는 기술에 대하여 논의한다.

• Structural Engineering and Mechanics
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• v.42 no.5
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• pp.747-760
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• 2012

In today's online social structure, people with electronic devices or network have been closely related to whether any of the activities, work, school, etc., is related to electronic devices, intelligent robot, and network control. The best mobility and the first rich media of these products as smart phones, smart phones rise rapidly in recent years, high speed processing performance and high free way to install software, deeply loved by many business people. However, not only for smart phone business aspects of the use, but also can engage in education of the teachers or the students are learning a great help. This study construct OCR-assisted learning software written by the JAVA made, and the installation is provided by the Android mobile phone users.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.701-702
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• 2006

In this paper, we embodied the environment monitoring system that can acquire correct data in real-time. And we used module that is 2.4GHz IEEE 802.15.4 / Zigbee network for radio communication between nodes. The nodes sense the data of temperature, humidity, illumination periodically. The nodes store the data in their buffer and transmit. We confirmed that the system is in real-time as it is changed instantly due to the varying environment by the simulation Therefore, we can construct the efficient and correct system as applied this system to monitor the environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.474-476
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• 2018

Natural disasters destroy decades of human effort and investments, thereby placing new demands on society for reconstruction and rehabilitation. In most case, the natural phenomena triggering the disasters are beyond human control. In order to solve the problems that the information resources can not be shared among disaster management sectors and their work is hard to be coordinated in city, an idea of application of ubiquitous sense network and ICT technology to model the architecture of the disaster prevention system based on the analysis of characteristics of disasters.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.1-4
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• 2005

Information communication environment integrates communication, broadcasting and internet, and Digital Convergence service emerges in result. Thus, the effective routers are needed so that they can transmit a huge number of data to core internet through appropriate base center. Therefore, the network guaranteeing QoS in transport layer supports interoperability with different wireless networks. So as to users receive necessary information anywhere seamlessly, the network architecture focuses on packet transmission and it is efficient for the control layer switches and controls packets between different networks. Since individual users take advantage of different services and data, the effective router architecture must be designed. Hence in this paper we design monitoring technique to solve security problem and to support premium service to ultimate users. Thereafter, we run opnet simulation and show the improvement of proposed router architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.423-430
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• 2000

Future microcellular systems will require distributed network control. A packet-switched network is suitable for this requirement. The packet reservation multiple access(PRMA) is a Reservation-ALOHA like protocol for wireless terminals to transmit packet speech to a base station. It allows spatially distributed users in cellular systems to transmit packeted voice and data to a common base station using a shared channel. In the existing PRMA, the problem is that the voice packets may collide with the data packets due to simultaneous channel access. the problem may be a major performance degradation factor to a voice and data mixed system. We propose a new PRMA method that integrates voice and data traffic efficiently by resolving the collision problem between data and voice packets. The proposed PRMA method gives a performance improvement than the existing PRAMA method in terms of voice packet dropping probability and data delay characteristic. From analytic results, we can confirm that the proposed PRMA method show a performance improvement than the existing PRMA protocol.