• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.1
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• pp.62-69
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• 2008

In this paper, we proposed the real-time bio-signals monitoring system that is based on the ZigBee wireless sensor network and SIP. This system makes medical team and user easily confirm user's medical state irrelative to their location and time. The communication between medical sensors and the user's end device uses the ZigBee wireless sensor network. The power consumption was decreased because wireless sensor network does not use the Ad-hoc routing protocol but routing protocol that is based on tree structure. Our proposed system includes a wireless user's end device, monitoring console, SIP server and database server. This real-time bio-signals monitoring system makes possible to implement the U-health care services and improving efficiency of medical treatment services.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.64.1-64.1
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• 2016

YAM (Young Astronomers Meeting, 젊은 천문학자들의 모임)과 We Love Galaxies는 인적/학문적 네트워크가 중요시되는 시대의 흐름에 발맞춰 국내 천문학 전공 대학원생들을 위한 워크샵인 "2016 YAM & We Love Galaxies 공동 워크샵"을 강촌에서 개최하였습니다. 2016년 2월 24일부터 26일까지 2박 3일간 개최된 이번 워크샵에는 총 35명의 대학원생/학부생/박사후연구원이 참가하였고, 전원 포스터 발표를 통해 참여 학생 모두가 자신의 연구주제를 자유롭게 소개하고 교류할 수 있도록 하였습니다. 뿐만 아니라 대학원 생활 및 연구 활동에 관련된 9개의 주제를 가지고 조별 토론을 진행하였습니다. 본 발표에서는 "2016 YAM & We Love Galaxies 공동 워크샵" 의 성과와 학생들로부터 받은 피드백을 소개하고 대학원생 워크샵이 나아가야 할 방향에 대해 제시하고자 합니다.

• Convergence Security Journal
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• v.5 no.4
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• pp.67-72
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• 2005

The exponential increase of malicious and criminal activities in cyber space is posing serious threat which could destabilize the foundation of modern information society. In particular, unexpected network paralysis or break-down created by the spread of malicious traffic could cause confusion and disorder in a nationwide scale, and unless effective countermeasures against such unexpected attacks are formulated in time, this could develop into a catastrophic condition. In order to solve a same problem, this paper researched early detection techniques for only early warning of cyber threats with separate way the detection due to and existing security equipment from the large network. It researched the cyber example alert system which applies the module of based honeynet from the actual large network and this technique against the malignant traffic how many probably it will be able to dispose effectively from large network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2663-2669
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• 2010

During the past 5 years, domestic VoIP service has grown rapidly absorbing more than 8 million subscribers. More recently, the increase of enterprise or institutional subscribers become more dominant than individual subscribers. Supporting emergency services such as 119 in these scaled up VoIP services is very essential. In current domestic VoIP networks, the VoIP terminal's location information which are provided to the PSAP with the arriving emergency call depends on the information which are entered at the subscription time or updated by the subscribers when the terminal is moved to other place. This manual provision of location information which requires the user's intervention can result in serious failure in saving people in emergency situations, in case that users are negligent in entering the information or users enter the wrong information. In this paper, we propose an enhanced mechanism in which the terminal's location information is automatically offered by the network for emergency services in ethernet-based enterprise VoIP networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.794-797
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• 2015

As the interest in VANET is increased, a study on the beacon message transmission between vehicles is actively being made. IEEE 802.11p/1609.4 standard is based on a multichannel system consisting of multiple service channels (SCH) and a control channel (CCH). Multiple SCHs are defined for nonsafety data transfer, while the CCH is used to broadcast safety messages called beacons and control messages (i.e., service advertisement messages). However, most messages broadcast in the only one CCH belong to safety application that must be contested in dense vehicular network. This paper suggests safety message transfer algorithm in dense vehicular congestion. The proposed algorithm is that the priority of safety messages is decided by decision tree and messages are stored in proper queues according to their priorities. Then, safety messages with higher priorities are sent in turn by CCH in the assigned time. The proposed algorithm decreases the beacon transmission delay and increase on the probability of a successful beacon reception in an IEEE 802.11p/1609.4-based network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.491-494
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• 2017

Recently, IoT has been supported by ICT technology with a variety of ICT powers. In May 2014, Information and Communication Strategy Committee announced the 'Basic plan for Internet of Things'. Also on Febuary 24 this SAME year, KISA(Korea Internet&Security Agency) provides many projects related to IoT, such as announcement of 'K-Global Project' for start-up and venture support related to IoT and ICT companies. In contrast to the various services of Internet of Things, when a connection is made between object-to-object or person-to-object wired and wireless networks, security threats have occurred in the process of communication. We analyzed these kinds of security threats related to Internet of things, and gave a consideration for requirement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.77-80
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• 2017

One of the fundamental limits of Bluetooth Low Energy(BLE) is that the data transmission is available via singlehop connection. In this research, we suggested the stable multihop transmission method to overcome this limitation. In multihop connection situation, multiple singlehop connection should be made and disconnected dynamically. Therefore, we stored the data within the GATT layer and tried to send it dynamically. We divided whole process as 4 states, and let each nodes transfers around each states to make data connection safely. Also, we set the transfer policy between each states during the transmission to make a robust system. From the experiment in real-time environment, we proved that our method showed high rate of packet delivery in a multihop network, which consists of more than 3 nodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1044-1047
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• 2013

Wireless Mesh Network (WMN) provides effective Internet Service accesses to users by utilizing multi-rate and multi-channel. In multi-rate networks, the Rate Anomaly (RA) problem occurs, the problem that low-rate link degrades the performance of high-rate link. In this paper we propose Rate Gap Minimum Channel Assignment (RGM-CA) protocol that select the minimal rate gap parent node and assign the channel in order to mitigates the rate anomaly problem. RDM-CA protocol is efficient because it consider rate anomaly, channel diversity and node connectivity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.2014-2026
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• 1997

In this paper, the performances of wireless asynchronous transfer mode (ATM) cell transmission in mobile work are analyzed. We adopt 16Star QAM as amodulation technique in wireless channel and considered Reed-Solomon, convolutional, and concatenated coding to improve the error rate performances, and also proposed the Partial Concatenated Coding (PCC) technique as UEP(unequal error protection) code for efficient transmission of ATM cell in the air interface. We consider Doppler's effect, Rician fading, and diversity technique of maximal-ratio combining (MRC) for mobile channel model. For performance measure, we analyze bit error rate, ATM cell loss probability, ATM cell error probability, and network performances of ATM cell transmission delay and throughput. The numerical results show that the adoption of PCC is a prospective way for the evolution of future wireless ATM network on mobile environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.338-347
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• 2012

In this paper, we propose the cooperative transmission scheme (CTS) for system throughput maximization in OFDMA based enterprise femtocell networks. In our scheme, the user equipment (UE) can receive the desired signal from serving femtocell BS (fBS) as well as an adjacent fBS. Thus, UE achieves an improved signal to interference plus and noise ratio (SINR) by the synchronized two signals. The performances of this strategy consider not only the call-level quality of service (QoS) but also the packet-level QoS. We first measure the call blocking probability and utilization for the downlink resources for various offered load in femtocell. Based on that, the outage probability and effective throughput of the system are simulated. Simulation results show that the proposed scheme can reduce the outage probability for enterprise femtocell compared with conventional systems.