• ETRI Journal
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• 제30권5호
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• pp.627-633
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• 2008

The technologies for wireless communication, sensing, and computation are each progressing at faster and faster rates. Notably, they are also being combined for an amazingly large multiplicative effect. It can be envisioned that the world will eventually be covered by networks of networks of smart sensors and actuators. This fact will give rise to revolutionary applications. However, to make this vision a reality, many research challenges must be overcome. This paper describes a representative set of new applications and identifies several key research challenges.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 춘계학술발표대회
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• pp.1100-1101
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• 2007

This paper proposes an efficient mechanism of node membership verification within the groups of sensors in a wireless sensor network (WSN). We utilize one-way accumulator to check the memberships of the legitimate nodes in a secure way. Our scheme also supports the addition and deletion of nodes in the groups in the network. Our analysis shows that, our scheme could be well-suited for the resource constrained sensors in a sensor network and it provides a lightweight mechanism for secure node membership verification in WSN.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.943-961
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• 2020

With the advent of IoT technology and Big Data computing, the importance of WSNs (Wireless Sensor Networks) has been on the rise. For energy-efficient and collection-efficient delivery of any sensed data, lots of novel wireless medium access control (MAC) protocols have been proposed and these MAC schemes are the basis of many IoT systems that leads the upcoming fourth industrial revolution. WSNs play a very important role in collecting Big Data from various IoT sensors. Also, due to the limited amount of battery driving the sensors, energy-saving MAC technologies have been recently studied. In addition, as new IoT technologies for Big Data computing emerge to meet different needs, both sensors and sinks need to be mobile. To guarantee stability of WSNs with dynamic topologies as well as frequent physical changes, the existing MAC schemes must be tuned for better adapting to the new WSN environment which includes energy-efficiency and collection-efficiency of sensors, coverage of WSNs and data collecting methods of sinks. To address these issues, in this paper, a self-organization scheme for mobile sensor networks with mobile multiple sinks has been proposed and verified to adapt both mobile sensors and multiple sinks to 3-dimensional group management MAC protocol. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of the various usage cases. Therefore, the proposed self-organization scheme might be adaptable for various computing and networking environments with big data.

• 한국항행학회논문지
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• 제20권3호
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• pp.252-257
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• 2016

본 논문에서는 IEEE 802.11ax에서 제안하는 임의 접근 기술을 이용한 무선랜 기반 센서 네트워크의 접속 기법을 제안한다. 제안하는 기법은 상향 데이터를 가지고 있는 예비 접속 단말들에 대하여 접속, 대기, 포기의 세 구간으로 나누어진 정수 단위의 OFDMA BackOFF counter (OBO)를 임의로 선택하게 하여 센서 단말의 실질적인 접속을 제어할 수 있다. 제안하는 기법은 비행기 등과 같이 다수의 센서와 연결이 필요한 센서 네트워크에 효과적으로 사용할 수 있다. 제안하는 방법을 사용하면, 기체내의 센서들은 본 논문에서 제안한 차등 OBO 매개변수를 사용한 접속 방법에 따라 접속을 시도하여 접속 용량을 초과하는 수의 단말을 효과적으로 제어할 수 있다. 또한 본 논문은 제안하는 기법에서 최적의 효율을 얻기 위한 관련 파라미터들에 대한 수학적 분석을 함께 제공한다. 본 논문의 분석 결과에 따르면 제안하는 기법을 통해 다수의 센서들의 접속이 최적의 효율에 가깝게 관리되었다.

• Smart Structures and Systems
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• 제18권5호
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• pp.885-909
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• 2016

Advances in low-cost wireless sensing have made instrumentation of large civil infrastructure systems with dense arrays of wireless sensors possible. A critical issue with regard to effective use of the information harvested from these sensors is synchronized sensing. Although a number of synchronization methods have been developed, most provide only clock synchronization. Synchronized sensing requires not only clock synchronization among wireless nodes, but also synchronization of the data. Existing synchronization protocols are generally limited to networks of modest size in which all sensor nodes are within a limited distance from a central base station. The scale of civil infrastructure is often too large to be covered by a single wireless sensor network. Multiple independent networks have been installed, and post-facto synchronization schemes have been developed and applied with some success. In this paper, we present a new approach to achieving synchronized sensing among multiple networks using the Pulse-Per-Second signals from low-cost GPS receivers. The method is implemented and verified on the Imote2 sensor platform using TinyOS to achieve $50{\mu}s$ synchronization accuracy of the measured data for multiple networks. These results demonstrate that the proposed approach is highly-scalable, realizing precise synchronized sensing that is necessary for effective structural health monitoring.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.799-802
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• 2005

In this paper, we analyses of Key Management Protocol for Wireless Sensor Networks in Wireless Sensor Networks. Wireless sensor networks have a wide spectrum of civil military application that call for security, target surveillance in hostile environments. Typical sensors possess limited computation, energy, and memory resources; therefore the use of vastly resource consuming security mechanism is not possible. In this paper, we propose a cryptography key management protocol, which is based on identity based symmetric keying.

• 비파괴검사학회지
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• 제24권5호
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• pp.494-498
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• 2004

현대의 대형 건물은 복잡한 전기 배선 또는 가스 배관 등의 설비를 갖추고 있어서 다양한 화재 사고가 발생할 가능성이 커졌다. 이에 따라 무선의 다점 온도 측정 센서를 손쉽게 여러 위치에 설치 가능하도록 저렴하게 개발하여 적용함에 의하여 화재를 조기에 탐지하고 그 피해의 크기를 최소화하는 것이 필요하다. 무선 온도 센서의 송신기는 4채널로 9600 bps의 전송속도와, 10 mW의 출력으로 915 MHz 통신 주파수를 갖고 수신기와 작동되도록 구성하였다. 온도범위 $-55{\sim}150$도 사이에서 사용할 수 있도록 검증된 반도체 온도 센서 소자를 기본으로 사용하여 4개의 채널을 구성하고 실험을 수행한 결과 개발된 센서 시스템이 화재 탐지용으로 적용이 가능함을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.247-268
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• 2011

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting interval varies according to the type of application. Such considerations require an application-specific, parameter tuning paradigm allowing us to maximize energy conservation prolonging the operational network lifetime. In this paper, we propose a reporting interval adaptive, sensor control platform for energy-saving data gathering in wireless sensor networks. The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to application-dependent or time-varying, reporting interval requirements. The proposed sensor control platform is based upon a two phase clustering (TPC) scheme which constructs two types of links within each cluster - namely, direct link and relay link. The direct links are used for control and time-critical, sensed data forwarding while the relay links are used only for multi-hop data reporting. Sensors opportunistically use the energy-saving relay link depending on the user reporting, interval constraint. We present factors that should be considered in deciding the total number of relay links and how sensors are scheduled for sensed data forwarding within a cluster for a given reporting interval and link quality. Simulation and implementation studies demonstrate that the proposed sensor control platform can help individual sensors save a significant amount of energy in reporting data, particularly in dense sensor networks. Such saving can be realized by the adaptability of the sensor to the reporting interval requirements.

• Smart Structures and Systems
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• 제12권1호
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• pp.23-39
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• 2013

In this article, a smart multifunctional optical system-on-a-chip (SOC) sensor platform is presented and its application for fiber Bragg grating (FBG) sensor interrogation in optical sensor networks is investigated. The smart SOC sensor platform consists of a superluminescent diode as a broadband source, a tunable microelectromechanical system (MEMS) based Fabry-P$\acute{e}$rot filter, photodetectors, and an integrated microcontroller for data acquisition, processing, and communication. Integrated with a wireless sensor network (WSN) module in a compact package, a smart optical sensor node is developed. The smart multifunctional sensor platform has the capability of interrogating different types of optical fiber sensors, including Fabry-P$\acute{e}$rot sensors and Bragg grating sensors. As a case study, the smart optical sensor platform is demonstrated to interrogate multiplexed FBG strain sensors. A time domain signal processing method is used to obtain the Bragg wavelength shift of two FBG strain sensors through sweeping the MEMS tunable Fabry-P$\acute{e}$rot filter. A tuning range of 46 nm and a tuning speed of 10 Hz are achieved. The smart optical sensor platform will open doors to many applications that require high performance optical WSNs.

• Smart Structures and Systems
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• 제12권1호
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• pp.73-95
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• 2013

Nine deoxyribonucleic acid (DNA) sequences were used to functionalize single-walled carbon nanotube (SWNT) sensors to detect the trace amount of methanol, acetone, and HCl in vapor. DNA 24 Ma (24 randomly arranged nitrogenous bases with one amine at each end of it) decorated SWNT sensor and DNA 24 A (only adenine (A) base with a length of 24) decorated SWNT sensor have demonstrated the largest sensing responses towards acetone and HCl, respectively. On the other hand, for the DNA GT decorated SWNT sensors with different sequence lengths, the optimum DNA sequence length for acetone and HCl sensing is 32 and 8, separately. The detection of methanol, acetone, and HCl have identified that DNA functionalized SWNT sensors exhibit great selectivity, sensitivity, and repeatability with an accuracy of more than 90%. Further, a sensor array composed of SWNT functionalized with various DNA sequences was utilized to identify acetone and HCl through pattern recognition. The sensor array is a combination of four different DNA functionalized SWNT sensors and two bare SWNT sensors (work as reference). This wireless sensing system has enabled real-time gas monitoring and air quality assurance for safety and security.