• Title/Summary/Keyword: Health Sensor

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Wireless health monitoring of stay cable using piezoelectric strain response and smart skin technique

  • Kim, Jeong-Tae;Nguyen, Khac-Duy;Huynh, Thanh-Canh
    • Smart Structures and Systems
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    • v.12 no.3_4
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    • pp.381-397
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    • 2013
  • In this paper, wireless health monitoring of stay cables using piezoelectric strain sensors and a smart skin technique is presented. For the cables, tension forces are estimated to examine their health status from vibration features with consideration of temperature effects. The following approaches are implemented to achieve the objective. Firstly, the tension force estimation utilizing the piezoelectric sensor-embedded smart skin is presented. A temperature correlation model to recalculate the tension force at a temperature of interest is designed by correlating the change in cable's dynamic features and temperature variation. Secondly, the wireless health monitoring system for stay cables is described. A piezoelectric strain sensor node and a tension force monitoring software which is embedded in the sensor are designed. Finally, the feasibility of the proposed monitoring technique is evaluated on stay cables of the Hwamyung Grand Bridge in Busan, Korea.

Design of U-Health System based on Embedded Event Filtering (EEF 기반의 U-Health 시스템 설계)

  • Kim, Jae-In;Na, Chul-Su;Han, Dae-Young;Kim, Dae-In;Hwang, Bu-Hyun
    • The Journal of the Korea Contents Association
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    • v.9 no.2
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    • pp.88-96
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    • 2009
  • In this paper we suggest the EEF technique to improve the performance of U-Health System. The idea of the EEF technique is that a sensor node sends only the abnormal data of patients to the base node. This technique reduces the amount of data transfer between a base node and sensor nodes, and so the power consumption of sensor nodes will be saved. And also the processing cost of base node will be reduced. In the suggested U-Health System based on EEF technique, electrocardiogram sensors and GPS sensors are used to send the electrocardiogram and position information of patients to a server. The server analyzes the health state of patients from base nodes and sends the information about the patients in the emergent state to the nearest hospital. Through the simulation, we have confirmed the suitability of EEF technique for U-Health System.

Wireless sensor network design for large-scale infrastructures health monitoring with optimal information-lifespan tradeoff

  • Xiao-Han, Hao;Sin-Chi, Kuok;Ka-Veng, Yuen
    • Smart Structures and Systems
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    • v.30 no.6
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    • pp.583-599
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    • 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.

A versatile software architecture for civil structure monitoring with wireless sensor networks

  • Flouri, Kallirroi;Saukh, Olga;Sauter, Robert;Jalsan, Khash Erdene;Bischoff, Reinhard;Meyer, Jonas;Feltrin, Glauco
    • Smart Structures and Systems
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    • v.10 no.3
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    • pp.209-228
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    • 2012
  • Structural health monitoring with wireless sensor networks has received much attention in recent years due to the ease of sensor installation and low deployment and maintenance costs. However, sensor network technology needs to solve numerous challenges in order to substitute conventional systems: large amounts of data, remote configuration of measurement parameters, on-site calibration of sensors and robust networking functionality for long-term deployments. We present a structural health monitoring network that addresses these challenges and is used in several deployments for monitoring of bridges and buildings. Our system supports a diverse set of sensors, a library of highly optimized processing algorithms and a lightweight solution to support a wide range of network runtime configurations. This allows flexible partitioning of the application between the sensor network and the backend software. We present an analysis of this partitioning and evaluate the performance of our system in three experimental network deployments on civil structures.

Development of Health Monitoring System Using Self Magnetization Magnetostrictive Sensor (자기자화자왜센서를 이용한 설비 off-line Health Monitoring 시스템 개발)

  • Kim, Yi-Gon;Moon, Hong-Sik;Kim, Jun;Kim, Ji-Hyeon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.4
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    • pp.481-486
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    • 2012
  • This thesis examines the development and application of 'Health Monitoring System' which monitors periodically the state of a pipe of petrochemical plant by using magnetostrictive sensor technology. The existing guided-wave inspection methods cannot be applied to welding part inspection in pipe, and has a limit of precision when applied to general parts because of noise, reflected waves, and so on. This technology uses the information on displacement of a defect through periodic monitoring, which makes more precise inspection, and can be utilized very usefully in a petrochemical plant.

Calibration of Health Monitoring System installed in the Railway Bridges (철도교 상시계측시스템의 교정 및 교정상수 설정에 관한 연구)

  • 박준오;이준석;최일윤;민경주
    • Journal of the Korean Society for Railway
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    • v.5 no.3
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    • pp.148-157
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    • 2002
  • A health monitoring system becomes a useful tool to obtain information on long term behavior of the important railway structures such as very long span and special type bridges. The health monitoring system not only gives the direct measurement data of the railway bridges but also provides the basic data on the maintenance of the structures. Therefore, periodic calibrations of the health monitoring system will be a necessary step toward precise and accurate assessment of the railway bridges. In this study, the calibration and gauge factor readjustment process made for the health monitoring system installed in the railroad bridges is reviewed and some findings are explained in detail: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in full length. Based on the regression results, it was found that the gauge factors need to be readjusted according to the regression equation but, since the deviation or shift is not serious so far, long-term observation on each sensor is also recommended. Future work will be concentrated on the long-term analysis of each sensor and on the database creation so that the assessment of the structures is possible.

Optimal sensor placement for structural health monitoring based on deep reinforcement learning

  • Xianghao Meng;Haoyu Zhang;Kailiang Jia;Hui Li;Yong Huang
    • Smart Structures and Systems
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    • v.31 no.3
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    • pp.247-257
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    • 2023
  • In structural health monitoring of large-scale structures, optimal sensor placement plays an important role because of the high cost of sensors and their supporting instruments, as well as the burden of data transmission and storage. In this study, a vibration sensor placement algorithm based on deep reinforcement learning (DRL) is proposed, which can effectively solve non-convex, high-dimensional, and discrete combinatorial sensor placement optimization problems. An objective function is constructed to estimate the quality of a specific vibration sensor placement scheme according to the modal assurance criterion (MAC). Using this objective function, a DRL-based algorithm is presented to determine the optimal vibration sensor placement scheme. Subsequently, we transform the sensor optimal placement process into a Markov decision process and employ a DRL-based optimization algorithm to maximize the objective function for optimal sensor placement. To illustrate the applicability of the proposed method, two examples are presented: a 10-story braced frame and a sea-crossing bridge model. A comparison study is also performed with a genetic algorithm and particle swarm algorithm. The proposed DRL-based algorithm can effectively solve the discrete combinatorial optimization problem for vibration sensor placements and can produce superior performance compared with the other two existing methods.

A Study on the Arterial Pulse Wave Measuring System of an Oral Cavity (구강 내부 맥파 계측을 위한 센서 시스템 연구)

  • Kim, Kyung-Ho
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.4
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    • pp.43-47
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    • 2007
  • In this paper, we propose a novel sensor system for measuring the arterial pulse in an oral cavity. In order to measure pulse wave in oral cavity, the proposed system is designed with reflection type arterial wave sensor, not by using transmission type arterial pulse wave sensor. Driving circuit through pulse current is designed for solving self-heating problem of LED. The effectiveness of the proposed sensor system is compared with pulse wave between pulse wave of oral cavity and other body parts as well as with characteristic measurements. The experiment shows that the proposed sensor system is adaptive to capturing consecutive and meaningful biometric signals through the variation of pulse wave changes in oral cavity when exercising. The study result expects to design and develop mobile sensors which could be adapted to healthcare devices.

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Ambient Vibration-Measurement of Real Building Structure by Using Fiber Optic Accelerometer System

  • Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.6
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    • pp.373-379
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    • 2006
  • Vibration-based structural health monitoring is one of non-destructive evaluation (NDE) techniques for civil infrastructures. This paper presents a novel fiber optic accelerometer system to monitor civil engineering structures and a successful application of the novel sensor system for measuring ambient vibration of a real building structure. This sensor system integrates the Moire fringe phenomenon with fiber optics to achieve accurate and reliable measurements. The sensor system is immune to electromagnetic (EM) interference making it suitable for difficult applications in such environments involving strong EM fields, electrical spark-induced explosion risks, and cabling problems, prohibiting the use of conventional electromagnetic accelerometers. A prototype sensor system has been developed, together with a signal processing software. The experimental studies demonstrated the high-performance of the fiber optic sensor system. Especially, the sensor was successfully used for monitoring a real building on UCI (University of California Irvine, USA).

Railway structure health monitoring using innovative sensing technologies (첨단계측센서를 이용한 철도 구조물의 모니터링)

  • Lee, Kyu-Wan;Jung, Sung-Hoon;Park, Eun-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.772-777
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    • 2008
  • Recent development of fiber optic sensors and wireless sensor technology, made structural health monitoring of railway structures cost effective. In this paper, a micro bending fiber optic rail pad sensors are evaluated for train axle force measurement. In order to assess the usability of FBG fiber optic sensors for short-term bridge measurement, the FBG sensors and conventional strain gauges are installed at the same points and the strain results are compared. Also the impact factors are calculated using the FBG strain responses and the results are compared with the conventional sensor responses. A running KTX train was instrumented with wireless sensor system to measure the vibration characteristics and the results are compared with conventional wire sensor system.

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