• 한국통신학회논문지
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• 제39C권1호
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• pp.90-96
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• 2014

센서 네트워크를 위한 표준인 IEEE802.15.4는 저전력, 저속 데이터 통신이 특징으로 주로 ZigBee 네트워크와 같은 Wireless Personal Area Network (WPAN)를 구성하기 위해 사용하고 있다. 그러나 최근 센서 네트워크 기반의 음성통신과 Session Initiation Protocol (SIP)를 연동하여 장거리 및 대규모 사용자를 지원하기 위한 연구가 활발히 진행되고 있다. 본 논문에서는 센서 네트워크 기반의 음성통신과 SIP를 연동하여 다수 사용자 지원하고 기존 시스템을 하나의 통합 Base Station으로 설계하였다. 또한, 설계한 Base Station의 성능을 평가하기 위하여 사용자수 증가에 따른 Packet 수와 Delay를 측정하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4781-4803
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• 2017

Environmental monitoring systems using Wireless Sensor Networks (WSNs) face the challenge of high power consumption, due to the high levels of multi-hop data communication involved. In order to overcome the issue of fast energy depletion, a proof-of-concept implementation proves that adopting a clustering algorithm in environmental monitoring applications will significantly reduce the total power consumption for environment sensor nodes. In this paper, an energy-efficient WSN-based environmental monitoring system is proposed and implemented, using eight sensor nodes deployed over an area of $1km^2$, which took place in the city of Tabuk in Saudi Arabia. The effectiveness of the proposed environmental monitoring system has been demonstrated through adopting a number of real experimental studies.

• 디지털콘텐츠학회 논문지
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• 제13권4호
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• pp.525-530
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• 2012

무선 센서 네트워크는 일반적으로 엔드 장치에 연결된 센서가 측정한 데이터를 코디네이터에게로 전달하는 자원이 한정된 장치들로 구성된다. 지그비는 무선 센서 네트워크에서 가장 많이 사용되는 프로토콜 중의 하나로서, 적정한 데이터 전송률을 가지면서 저전력, 저비용의 무선 통신을 지원하기 위해 표준으로 도입되었다. 이 논문에서는 TI의 CC2530 상에서 TI의 지그비 프로토콜 스택 이식과 UART 인터페이스를 구현하는 방법에 관하여 논의한다. 시리얼 포트를 통한 데이터 전송 과정을 시현함으로써 구현한 보드가 올바르게 동작됨을 보인다.

• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.6-11
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• 2018

It is important to find the random estimation points in wireless sensor network. A link quality indicator (LQI) is part of a network management service that is suitable for a ZigBee network and can be used for localization. The current quality of the received signal is referred as LQI. It is a technique to demodulate the received signal by accumulating the magnitude of the error between ideal constellations and the received signal. This proposed model accepts any number of random estimation point in the network and calculated its nearest anchor centroid node pair. Coordinates of the LQI sphere are calculated from the pair and are added iteratively to the initially estimated point. With the help of the LQI and weighted centroid localization, the proposed system finds the position of target node more accurately than the existing system by solving the problems related to higher error in terms of the distance and the deployment of nodes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.171-173
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• 2006

Because sensor networks use wireless communication, they are vulnerable to attacks which are more difficult launch in the wired domain. Many wired networks benefit from their inherent physical security properties. It is unlikely that an adversary will dig up the Internet backbone and splice into the line. However, wireless communications are difficult to protect; they are by nature a broadcast medium. In a broadcast medium, adversaries can easily eavesdrop on, intercept, inject, and alter transmitted data. In addition, adversaries are not restricted to using sensor network hardware. We have analyzed the IEEE 802.15.4, ZigBee specification which includes a number of security provisions and options. In this paper, we highlight places where USN security considerations and home network attack scenarios.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.948-951
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• 2008

Ubiquitous sensor network (USN) based on ZigBee communication protocol has been used in various application fields, such as home-network, intelligent building and machine, logistics, environmental monitoring, military field, security field and etc. The ZigBee is targeted at radio-frequency application that require a low data rate, long battery life and secure network. Especially, the USN system can be applied efficiently to building-indoor where the complex geometry is adopted. In this study, all 90 points of railway cabin indoor were monitored for temperature and humidity using USN technology. All sensors were pre/post-calibrated and the temperature/humidity change were analyzed in a railway cabin in real-time. The results would be useful to develop the cabin heating, ventilating and air conditing (HVAC) system to meet all passengers' thermal comfort regardless of their seat position.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.172-174
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• 2007

An electronic watt-hour meter with high-precision measurement technology can provide many valuable metering data of a real-time system measurements, such as per-phase voltage, ampere, active power, reactive power, apparent power, power factor, and system frequency. Also many of accumulated metering data such as active energy, reactive energy, apparent energy, and load profile can be gettable from an electronic watt-hour meter[1]. This paper presents an approach of the small-sized AMR (Automatic Meter Reading) that provides customers with a very valuable electrical service. This AMR service transmits lots of a valuable metering data by using ZigBee communication module, so that users resided in their premises can use the information to audit a power quality and improve their electrical conditions by using the PQ monitoring device equipped with ZigBee receiver. This PQ monitoring device shows metering data on LCD and transmits to the PC through an internal network. Also, the device can keep the valuable meter data into a built-in non-volatile memory. The final goal of this paper is to better understand the power quality of electrical systems and offer the power qualify information for the convenience of all power consumers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1751-1767
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• 2016

Home security has become the prime concern for everyone in present scenario. In this work an attempt has been made to develop a home security system which is accessible, affordable and yet effective.The proposed system is based on 'Remote Embedded Control System' (RECS) which works both on the web and gsm platform for authentication and monitoring. This system is therefore cost effective as it relies on existing network infrastructure. As PCA is most popular and efficient algorithm for face recognition, it has been usedin this work. Next to it an interface has been developed for communication purpose in the embedded security system through the ZigBee module. Based on this embedded system, automated control of door movement has been implemented through electromagnetic door lock technology. This helps the users to monitor the real-time activities through web services/SMS. The web service consists of either web browser command or e-mail provision. The system establishes the communication between the system and authenticated user. The e-mail received by the system from the authorized person will monitor and control the real-time operation and door lock. The entire control system is reinforced using ARM1176JZF-S microcontroller and tested for actual use in the home environment. The result shows the experimental verification of the proposed system.

• 한국ITS학회 논문지
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• 제21권4호
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• pp.157-166
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• 2022

IoT 기술 중에서 가장 많이 쓰이는 무선 통신 기술에는 ZigBee, WiFi, Bluetooth, Z-Wave 등이 있다. 그 중에서 Z-Wave는 현재 세계 시장 점유율이 60%로 선호하는 기술 중 하나이다. 본 논문에서는 Z-Wave 프로토콜을 이용한 온습도 센서 모듈을 구현하였다. 온습도 센서 모듈의 동작을 위하여 Z-Wave 프로토콜을 분석하고, 컨트롤러 모듈의 펌웨어를 탑재하여 구현하였고, 센서 모듈은 데이터 시트를 참고하여 설계 및 제작하였다. 또한 센서의 온습도 정보를 모니터링하는 프로그램을 개발하여 이를 확인하였으며, Z-Wave 모듈의 통달거리 시험, 수신데이터 성공률, 저전력 시험 등을 통하여 성능을 확인하였다.

• 한국정보통신학회논문지
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• 제10권8호
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• pp.1465-1470
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• 2006

본 논문에서는 단거리 무선 통신의 새로운 국제 표준으로 부상하고 있는 2.4 GHz ZigBee 응용을 위한 저전력 CMOS LNA(Low Noise Amplifier)를 설계하였다. 제안한 구조는 전류 재사용 기법을 이용한 2단 cascade구조이며 회로의 설계에서 TSMC $0.18{\mu}m$ CMOS 공정을 사용하였다. 전류 재사용단은 두 단의 증폭기 전류를 공유함으로써 LNA의 전력 소모를 적게 하는 효과를 얻을 수 있다. 본 논문에서는 LNA설계 과정을 소개하고 ADS(Advanced Design System)를 이용한 모의실험 결과를 제시하여 검증하였다. 모의실험 결과, 1.0V의 전압이 인가될 때 1.38mW의 매우 낮은 전력 소모를 확인하였으며 이는 지금까지 발표된 LNA 중 가장 낮은 값이다. 또한 13.83dB의 최대 이득, -20.37dB의 입력 반사 손실, -22.48dB의 출력 반사 손실 그리 고 1.13dB의 최소 잡음 지수를 보였다.