• Smart Structures and Systems
• /
• 제30권6호
• /
• pp.583-599
• /
• 2022

In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.

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

• Structural Monitoring and Maintenance
• /
• 제1권1호
• /
• pp.47-67
• /
• 2014

This study has been motivated to examine the performance of a wireless sensor system under the typhoons as well as to analyze the effect of the typhoons on the bridge's vibration responses and the variation of cable forces. During the long-term field experiment on a real cable-stayed bridge in years 2011-2012, the bridge had experienced two consecutive typhoons, Bolaven and Tembin, and the wireless sensor system had recorded data of wind speeds and vibration responses from a few survived sensor nodes. In this paper, the wireless structural health monitoring of stay cables under the two consecutive typhoons is presented. Firstly, the wireless monitoring system for cable-stayed bridge is described. Multi-scale vibration sensor nodes are utilized to measure both acceleration and PZT dynamic strain from stay cables. Also, cable forces are estimated by a tension force monitoring software based on vibration properties. Secondly, the cable-stayed bridge with the wireless monitoring system is described and its wireless monitoring capacities for deck and cables are evaluated. Finally, the structural health monitoring of stay cables under the attack of the two typhoons is described. Wind-induced deck vibration, cable vibration and cable force variation are examined based on the field measurements in the cable-stayed bridge under the two consecutive typhoons.

• International Journal of Contents
• /
• 제4권2호
• /
• pp.1-6
• /
• 2008

Pre schools with state of the art facilities that would provide not just academic excellence but also ensure the safety and provide efficient healthcare to their pupils relative to Atopic Dermatitis with Asthma is the main objective of this research One of the most promising applications of sensor networks is for human healthcare monitoring. Due to recent technological advances in sensor, low power microelectronics and miniaturization, and wireless networking enable the design and proliferation of this wireless sensor networks capable of autonomously monitoring and controlling environments. Thus, this research presents the utilization of such microelectronic sensor and plots the hardware and software architecture of a wireless sensor network system with real-time pupil monitoring that integrates vital sign sensors, location sensor and allergen sensor. This proposed architecture for wearable sensors can be used as active tags which can track pupil's location within the school's premises, identify possible atopic dermatitis with asthma allergens, it would monitor and generate a health status report of the pupil.

• 한국통신학회논문지
• /
• 제36권8B호
• /
• pp.1003-1011
• /
• 2011

본 논문에서는 우선 센서네트워크를 기반으로 실시간 다중소스 센서데이터 관리시스템을 제안하고 구현하였다. 제안된 관리시스템은 대상시스템의 상태를 효율적으로 감시하고 제어하기 위해서 다수의 센서들로부터 수집된 실시간 데이터를 무선으로 서버로 전송하며, 이를 분석하여 동작하도록 설계되었다. 제안된 시스템은 원격지에서 세포배양장치와 같은 다중 소스 센서들을 클러스터 형태로 구성하고, 이들로부터 발생하는 센서데이터를 제어, 전송하며, 각 소스로부터 수신된 데이터를 소스별로 구분하여 관리가 가능하도록 구현하였다. 제안된 시스템의 성능을 평가하기 위해서 전송거리에 따른 전송 지연시간과 다중소스로부터 발생된 데이터 손실률을 측정하여 분석하였으며, 그 결과 우수한 성능을 보임을 확인하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.631-634
• /
• 2009

최근 무선통신, MEMS 소자, 센서 및 베터리 분야의 발전은 저가, 저전력 다기능 소형 센서 노드를 가능하게 한다. 다수의 소형 센서 노드는 무선 통신을 통해 센서 네트워크를 형성한다. 센서 네트워크는 전통적인 센서를 통해 중요한 개선을 나타내며 지그비 무선 이미지 전송에 대한 연구는 산업과 과학 분야에서 주요 연구 테마가 되고 있다. 본 논문에서는 지그비 무선 이미지 센서 노드와 멀티미디어 모니터링 서버 시스템을 디자인하였다. 구현된 시스템은 임베디드 프로세서, CMOS 이미지 센서, 이미지 획득 및 처리부, 지그비 RF 모듈, 전력공급 및 원격 모니터링 서버 시스템으로 구성된다. 앞으로 지그비 무선 이미지 센서 노드 및 모니터링 서버 시스템의 성능을 개선하고 에너지 효율적인 지그비 무선 이미지 전송 프로토콜과 모바일 네트워크와의 연동에 대한 연구를 진행할 예정이다.

• 한국경영과학회지
• /
• 제35권2호
• /
• pp.53-69
• /
• 2010

This paper proposes an ant-based routing algorithm, Ant System-Routing in wireless Senor Networks(AS-RSN), for wireless sensor networks. Using a transition rule in Ant System, sensors can spread data traffic over the whole network to achieve energy balance, and consequently, maximize the lifetime of sensor networks. The transition rule advances one of the original Ant System by re-defining link cost which is a metric devised to consider energy-sufficiency as well as energy-efficiency. This metric gives rise to the design of the AS-RSN algorithm devised to balance the data traffic of sensor networks in a decentralized manner and consequently prolong the lifetime of the networks. Therefore, AS-RSN is scalable in the number of sensors and also robust to the variations in the dynamics of event generation. We demonstrate the effectiveness of the proposed algorithm by comparing three existing routing algorithms: Direct Communication Approach, Minimum Transmission Energy, and Self-Organized Routing and find that energy balance should be considered to extend lifetime of sensor network and increase robustness of sensor network for diverse event generation patterns.

• 한국정보기술응용학회:학술대회논문집
• /
• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
• /
• pp.207-210
• /
• 2005

Ubiquitous computing is one of the key technology areas in the "Project on Development of Ubiquitous computing and network technology" promoted by the Ministry of Science and Technology as a frontier business of the $21^{st}$ century in Korea, which is based on the new concept merging physical space and computer-based cyber space. With recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low-power consumption wireless micro sensor nodes have been available. Using these smart sensor nodes, there are many activities to monitor real world, for example, habitat monitoring, earthquake monitoring and so on. In this paper, we introduce web-based real environment monitoring system incorporating wireless sensor nodes. It collects sensing data produced by some wireless sensor nodes and stores them into a database system to analyze. Our environment monitoring system is composed of a networked camera and environmental sensor nodes, which are called Mica2 and developed by University of California at Berkeley. We have modified and ported network protocols over TinyOS and developed a monitoring application program using the MTS310 and MTS420 sensors that are able to observe temperature, relative humidity, light and accelerator. The sensed data can be accessed user-friendly because our environment monitoring system supports web-based user interface. Moreover, in this system, we can setup threshold values so the system supports a function to inform some anomalous events to administrators. Especially, the system shows two useful pre-processed data as a kind of practical uses: a discomfort index and a septicity index. To make both index values, the system restores related data from the database system and calculates them according to each equation relatively. We can do enormous works using wireless sensor technologies, but just environment monitoring. In this paper, we show just one of the plentiful applications using sensor technologies.

• 한국ITS학회 논문지
• /
• 제7권5호
• /
• pp.139-146
• /
• 2008

무선 센서 네트워크 관련 응용 시스템은 환경오염, 건물통제, 홈 오토메이션 등의 역할을 수행할 것으로 예상된다. 본 논문에서는 지하철 역사 내 인명 및 화재 피해 등을 줄이기 위한 무선 센서 네트워크 기반의 지하철 응급 상황 조치 시스템에 대해 기술한다. 본 시스템의 센서 노드는 온도, 조도, 연기, 인체 감지 등을 통해 지하철 역사내 발생 할 수 있는 사고를 실시간 감지한다. 이러한 실시간 센서 감지와 무선 네트워킹을 통해 인명과 재산의 피해를 최소화 하고자 한다.

• Journal of information and communication convergence engineering
• /
• 제7권3호
• /
• pp.258-262
• /
• 2009

A Practical application of environmental monitoring system based on wireless sensor node network with the core of embedded system STR711FR2 microprocessor is presented in the paper. The adaptable and classifiable wireless sensor node network is used to achieve the data acquisition and multi-hop wireless communication of parameters of the monitoring base station environment including repeaters. The structure of the system is proposed and the hardware architecture of the system is designed, and the system operating procedures is proposed. As a result of field test, designed hardware platform operated with 50kbps bit rate and 5MHz channel spacing at 2040Hz. The wireless monitoring system can be managed and swiftly retreated without support of base station environmental monitoring.