• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.91-94
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• 2004

Ubiquitous sensor network is to manage and collect information autonomously by communicating user around device. Security requirements in Ubiquitous based on sensor network are as follows: a location of sensor, a restriction of performance by low electric power, communication by broadcasting, etc. We propose new mutual authentication protocol using a low power of sensor node. This protocol solved a low power problem by reducing calculation overload of sensor node using two steps, RM(Register Manager) and AM(Authentication Manager). Many operations performing the sensor node itself have a big overload in low power node. Our protocol reduces the operation number from sensor node. Also it is mutual authentication protocol in Ubiquitous network, which satisfies mutual authentication, session key establishment, user and device authentication, MITM attack, confidentiality, integrity, and is safe the security enemy with solving low electric power problem.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.689-709
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• 2010

In this paper, a low cost, low power but multifunctional wireless sensor node is presented for the impedance-based SHM using piezoelectric sensors. Firstly, a miniaturized impedance measuring chip device is utilized for low cost and low power structural excitation/sensing. Then, structural damage detection/sensor self-diagnosis algorithms are embedded on the on-board microcontroller. This sensor node uses the power harvested from the solar energy to measure and analyze the impedance data. Simultaneously it monitors temperature on the structure near the piezoelectric sensor and battery power consumption. The wireless sensor node is based on the TinyOS platform for operation, and users can take MATLAB$^{(R)}$ interface for the control of the sensor node through serial communication. In order to validate the performance of this multifunctional wireless impedance sensor node, a series of experimental studies have been carried out for detecting loose bolts and crack damages on lab-scale steel structural members as well as on real steel bridge and building structures. It has been found that the proposed sensor nodes can be effectively used for local wireless health monitoring of structural components and for constructing a low-cost and multifunctional SHM system as "place and forget" wireless sensors.

• ETRI Journal
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• 제45권4호
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• pp.570-580
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• 2023

Sensor nodes are the most significant part of a wireless sensor network that offers a powerful combination of sensing, processing, and communication. One major challenge while designing a sensor node is power consumption, as sensor nodes are generally battery-operated. In this study, we proposed the design of a low-power, long range-based wireless sensor node with flexibility, a compact size, and energy efficiency. Furthermore, we improved power performance by adopting an efficient hardware design and proper component selection. The Nano Power Timer Integrated Circuit is used for power management, as it consumes nanoamps of current, resulting in improved battery life. The proposed design achieves an off-time current of 38.17309 nA, which is tiny compared with the design discussed in the existing literature. Battery life is estimated for spreading factors (SFs), ranging from SF7 to SF12. The achieved battery life is 2.54 years for SF12 and 3.94 years for SF7. We present the analysis of current consumption and battery life. Sensor data, received signal strength indicator, and signal-to-noise ratio are visualized using the ThingSpeak network.

• 한국군사과학기술학회지
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• 제15권6호
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• pp.761-769
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• 2012

In this paper, we propose a low-power design strategy to minimize energy-consumption for surveillance and reconnaissance sensor networks. The sensor network consists of many different nodes with various operations such as target detection, packet relay, video monitoring, changing protocols, and etc. Each sensor node consists of sensing, computing, communication, and power components. These components are integrated on a single or multiple boards. Therefore, the power consumption of each component can be different on various operation types. First, we identified the list of components and measured power consumption for them from the first prototype nodes. Next, we focus on which components are the main sources of energy consumption. We propose many energy-efficient approaches to reduce energy consumption for each operation type.

• 한국정보통신학회논문지
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• 제18권7호
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• pp.1721-1726
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• 2014

유비쿼터스 컴퓨팅의 핵심 기술인 센서 네트워크 기술이 각광을 받으면서 다양한 종류의 센서 노드로 구성된 센서 네트워크에 대한 연구가 활발히 진행되고 있다. 센서 네트워크 어플리케이션들의 주요 트래픽 패턴은 몇몇의 센서 노드들로부터 싱크 노드로 패킷을 전송하는 타입의 단일 방향성 데이터 수집형태로 구성되어있으며 소스 노드, 중간 노드, 싱크 노드에 이르기 까지 각각 자신의 상위 노드를 곧 바로 깨움으로써 지연의 감소와 에너지 효율성을 이끌어냈다. 본 논문에서는 센서 노드의 지연 감소를 위해 2계층 클러스터 구조를 제시하고 이에 기존에 사용한 라우팅 프로토콜을 네트워크 시뮬레이션을 통해 비교 분석하였다.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.675-687
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• 2010

Structural Health Monitoring (SHM) is the science and technology of monitoring and assessing the condition of aerospace, civil and mechanical infrastructures using a sensing system integrated into the structure. Impedance-based SHM measures impedance of a structure using a PZT (Lead Zirconate Titanate) patch. This paper presents a low-power wireless autonomous and active SHM node called Autonomous SHM Sensor 2 (ASN-2), which is based on the impedance method. In this study, we incorporated three methods to save power. First, entire data processing is performed on-board, which minimizes radio transmission time. Considering that the radio of a wireless sensor node consumes the highest power among all modules, reduction of the transmission time saves substantial power. Second, a rectangular pulse train is used to excite a PZT patch instead of a sinusoidal wave. This eliminates a digital-to-analog converter and reduces the memory space. Third, ASN-2 senses the phase of the response signal instead of the magnitude. Sensing the phase of the signal eliminates an analog-to-digital converter and Fast Fourier Transform operation, which not only saves power, but also enables us to use a low-end low-power processor. Our SHM sensor node ASN-2 is implemented using a TI MSP430 microcontroller evaluation board. A cluster of ASN-2 nodes forms a wireless network. Each node wakes up at a predetermined interval, such as once in four hours, performs an SHM operation, reports the result to the central node wirelessly, and returns to sleep. The power consumption of our ASN-2 is 0.15 mW during the inactive mode and 18 mW during the active mode. Each SHM operation takes about 13 seconds to consume 236 mJ. When our ASN-2 operates once in every four hours, it is estimated to run for about 2.5 years with two AAA-size batteries ignoring the internal battery leakage.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.766-769
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• 2005

In a ubiquitous environment made up of multiple sensors, most sensors participate in communications with limited battery, and the sensor node isn't able to participate in communications when all the battery is used up. When an existing authentication method is used for the sensor node which has to participate in a long term communication with limited battery, it creates a problem by making the length of network maintenance or sensor node's operation time relatively shorte. Therefore, a network structure where RM (Register Manager) node and AM (Authentication Manager) node are imported to solve the energy consumption problem during a communication process is presented in this thesis. This offers a low power protocol based on safety through a mutual authentication during communications. Through registration and authentication manager nodes, each sensor nodes are ensured of safety and the algorithm of key's generation, encryption/descramble and authentication is processed with faster operation speed. So the amount of electricity used up during the communications between sensor nodes has been evaluated. In case of the amount of electrical usage, an average of $34.783\%$ for the same subnet and 36.855 for communications with two different subnets, are reduced. The proposed method is a protocol which maintains the limited battery for a long time to increase the effectiveness of energy usage in sensor nodes and can also increase the participation rate of communication by sensor nodes.

• 한국컴퓨터정보학회논문지
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• 제11권1호
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• pp.177-184
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• 2006

유비쿼터스 네트워크 통신에서 각 센서는 저 전력과 초경량으로 인해 여러 가지 제한을 가지므로 그동안 센서의 특성을 고려한 여러 가지 연구가 진행되어 왔다. 본 논문에서는 센서노드의 신분정보의 노출을 최소화하기 위하여 alias를 사용함으로써 등록과 인증을 수행하는 과정을 개선하고 익명성을 제고하는 방법을 제안하였다 등록과 인증과정에서 센서노드의 제한된 기능을 고려하여 RA(Relay Agent)를 도입하였고 SM(Service Manager)로부터 alias를 부여받아 각 센서노드의 신분정보의 익명성을 개선하였다. 센서노드의 개인 정보는 등록 및 인증과정은 물론 node간의 통신과정에서 안전한 보안이 보장되었으며, 계산 량 및 보안성 분석결과 센서노드의 계산 량 증가 없이 RA, SM의 연산 량 일부증가 만으로 보안수준이 향상되었음을 확인하였다.

• 한국멀티미디어학회논문지
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• 제13권10호
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• pp.1423-1435
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• 2010

무선 센서 네트워크를 구성하는 센서 노드는 배터리 기반의 제한된 전원과 낮은 연산 능력의 초경량 마이크로프로세서, 그리고 제한된 크기의 메모리 자원 등과 같은 하드웨어 사양을 가지고 있다. 이와 같은 제약 사항에도 불구하고 무선 센서 노드는 센싱 데이터의 실시간 처리 및 데이터 송수신 작업을 동시에 병행할 수 있어야 한다. 이에 본 논문에서는 배터리 작동식의 무선 센서 노드를 위한 에너지 효율적인 실시간 태스크 스케줄링 기법을 제안하였다. 제안한 에너지 효율적인 실시간 스케줄링 가법은 태스크의 실제 실행시간이 최악 실행시간보다 작을 경우에 발생되는 태스크의 실행 여유시간을 이용하여, 마이크로프로세서의 동작 주파수를 조절하고 무선 센서 노드의 전력 소비를 줄인다. 제안한 기법의 동작을 시험한 결과, 효율적인 전력 소비를 제공함과 동시에 실시간 태스크의 마감시한이 보장됨을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.733-736
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• 2013

유비쿼터스 컴퓨팅의 핵심 기술인 센서 네트워크 기술이 각광을 받으면서 다양한 종류의 센서 노드로 구성된 센서 네트워크에 대한 연구가 활발히 진행되고 있다. 센서 네트워크 어플리케이션들의 주요 트래픽 패턴은 몇몇의 센서 노드들로부터 싱크 노드로 패킷을 전송하는 타입의 단일 방향성 데이터 수집형태로 구성되어있으며 소스 노드, 중간 노드, 싱크 노드에 이르기 까지 각각 자신의 상위 노드를 곧 바로 깨움으로써 지연의 감소와 에너지 효율성을 이끌어냈다. 본 논문에서는 센서 노드의 지연 감소를 위해 2계층 클러스터 구조를 제시하고 이에 기존에 사용한 라우팅 프로토콜을 네트워크 시뮬레이션을 통해 비교 분석하였다.