• Smart Structures and Systems
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• 제30권6호
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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.

• Smart Structures and Systems
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• 제33권6호
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• pp.465-482
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• 2024

In this paper, a robust wireless sensor network configuration design method is proposed to develop the optimal configuration under the consideration of sensor failure and energy consumption. A malfunctioned sensor in a wireless sensor network may lead to data transmission failure of the entire sensing cluster, inducing severe deterioration in system identification performance. The proposed method determines a wireless sensor network configuration that is robust against sensor failure. By utilizing Bayesian inference, we introduce a robust indicator to evaluate the impact on estimation accuracy of sensor configurations with various malfunctioned sensors. Moreover, a network formation strategy is proposed to optimize the energy efficiency of the wireless sensor network configuration. Therefore, the resultant robust wireless sensor network configuration can operate with the minimum energy consumption while the measurement information of the sensor network with malfunctioned sensors can be guaranteed. The proposed method is illustrated by designing the robust wireless sensor network configurations of a truss model and a bridge model.

• Smart Structures and Systems
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• 제12권3_4호
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• pp.399-414
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• 2013

The smart sensor technology has opened new horizons for assessing and monitoring structural health of civil infrastructure. Smart sensor's unique features such as onboard computation, wireless communication, and cost effectiveness can enable a dense network of sensors that is essential for accurate assessment of structural health in large-scale civil structures. While most research efforts to date have been focused on realizing wireless smart sensor networks (WSSN) on bridge structures, relatively less attention is paid to applying this technology to buildings. This paper presents a decentralized damage detection using the WSSN for building structures. An existing flexibility-based damage detection method is extended to be used in the decentralized computing environment offered by the WSSN and implemented on MEMSIC's Imote2 smart sensor platform. Numerical simulation and laboratory experiment are conducted to validate the WSSN for decentralized damage detection of building structures.

• Smart Structures and Systems
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• 제10권3호
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• pp.271-298
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• 2012

Researchers have made significant progress in recent years towards realizing effective structural health monitoring (SHM) utilizing wireless smart sensor networks (WSSNs). These efforts have focused on improving the performance and robustness of such networks to achieve high quality data acquisition and distributed, in-network processing. One of the primary challenges still facing the use of smart sensors for long-term monitoring deployments is their limited power resources. Periodically accessing the sensor nodes to change batteries is not feasible or economical in many deployment cases. While energy harvesting techniques show promise for prolonging unattended network life, low power design and operation are still critically important. This research presents the WiSeMote: a new, fully integrated ultra-low power wireless smart sensor node and a flexible base station, both designed for long-term SHM deployments. The power consumption of the sensor nodes and base station has been minimized through careful hardware selection and the implementation of power-aware network software, without sacrificing flexibility and functionality.

• 한국구조물진단유지관리공학회 논문집
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• 제20권3호
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• pp.42-48
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• 2016

사회기반시설물의 안전성을 효과적으로 평가하고 모니터링하기 위해 무선 스마트 센서가 개발되어 전 세계적으로 연구가 진행되고 있다. 무선 스마트 센서는 통상 계측 및 임베디드 데이터 연산, 무선 통신이 가능한 공통점을 갖고 있어 기존의 유선 기반 센서가 가진 단점을 극복할 수 있을 것으로 기대되고 있다. 그러나 구조물의 장기 모니터링의 경우 내구성이 충분하지 못해 발생하는 센서 고장이나, 환경적 이유로 인한 무선 통신이 불안정할 경우 계측 데이터를 가져올 수 없는 문제가 발생할 수 있다. 본 연구에서는 무선 스마트 센서 기반의 네트워크에서 이와 같은 문제로 센서 노드에 무선 통신으로 접근할 수 없는 경우를 대처하기 위해, 칼만 필터 기반의 데이터 복구를 수행하여 무선 스마트 센서 네트워크의 신뢰성을 향상시키는 기법을 제안한다. 본 논문에서는 무선 스마트 센서의 연산 기능을 활용하여 네트워크 내에서 계측된 가속도 데이터를 바탕으로 유실된 센서의 가속도 계측 데이터를 추정한다. 개발된 무선 스마트 센서 네트워크 시스템의 성능을 확인하기 위해 단순보 구조에서 실험을 수행하여 추정된 가속도 응답과 계측 값을 비교하였다.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.131-135
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• 2011

본 논문에서는 에너지 센서 네트워크 적용을 위한 AC 전력센싱 기능과 지능형 대기전력 차단제어 기능을 가진 무선 스마트 플러그 설계와 적응식 대기전력 차단제어 알고리즘을 제안하고 구현하였다. 적응식 대기전력 차단제어 알고리즘은 사무기기나 가전기기마다 상이한 대기전력 문턱치를 학습기능에 의해 자동 감지하고, 적응 설정되게 함으로서 사용자의 편이성과 신뢰성 높은 대기전력 차단제어 기능을 제공하여 에너지소비 절감 효과를 극대화 할 수 있도록 하였다. 구현된 시제품의 기능을 검증한 결과, 설계 요구기능을 모두 만족하였으며 대기전력 소비를 절감할 수 있는 지능형 전력센서로서 실용성이 있음을 확인하였다.

• 전자공학회논문지CI
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• 제44권5호
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• pp.28-37
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• 2007

IEEE 1451 standard는 네트워크와 transducer간에 표준 interface를 정의한다. 본 논문에서는 IEEE 1451 Standard 기반의 data acquisition system과 무선 smart sensor node를 구성하기 위한 구조적인 모델을 제안한다. 제안 된 Network Capable Application Processor(NCAP)은 data acquisition의 역할과 smart sensor node와 네트워크 사이에 가교 역할을 한다. 또한 무선 sensor node에게 영향을 주지 않으면서 재구성이 가능하고 DB를 이용하여 transducer의 정확한 정보를 얻는다. Smart sensor node는 그 자신에 관한 기본적인 정보를 디지털 형식으로 제공하는 능력을 가지고 있다. 이 디지털 형식은 Transducer Electronic Data Sheet(TEDS)라 하며 sensor node의 plug-and-play 기능을 가능하게 한다. IEEE 1451.4에서 정의하고 있는 TEDS와 Template를 무선 환경에서 적용하기 위해 형식을 간략화 하였으며 ad-hoc routing을 통해 전송이 이루어진다. 본 연구 시스템은 의료정보 서비스를 제공하기 위한 목적으로 체온과 ECG(Electrocardiogram) 센서를 사용하였다. Template 형식은 센서들의 data sheet를 통해 결정하였으며 센서의 특징을 정확히 표현하기 위해 재구성하였다. NCA의 DB는 다양한 센서 개발에 따라 새로운 Template 및 하부 항목의 등록이 가능하도록 구현하였다.

• KIEAE Journal
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• 제14권6호
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• pp.23-29
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• 2014

It is essential to investigate the structure and the main characteristics of BSN (Bio-Sensor Network) platform in built smart healthcare environment while designing healthy housing facilities. For this study, WSN (Wireless Sensor Network) data transmission technologies have been employed with medical sensors, and optimal medical devices would provide various Web 2.0 services by connecting to the WiBro network. The BSN platform normally recognizes in surroundings of WBAN (Wireless Body Area Network) or WPAN (Wireless Personal Area Network), and it is possible to manage sensor nodes by utilizing SOAP (Simple Object Access Protocol) and REST (REpresentational State Transfer). In addition, the feature of SNMP (Simple Network Management Protocol) for mobile gateway is also included for being adapted to huge network structure. Finally, BSN platform will play a role as important clues for developing personal WSN service models for smart healthy housing properties.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.173-181
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• 2023

Data collection is an essential element in the construction and operation of a smart factory. The quality of data collection is greatly influenced by network conditions, and existing wireless network systems for IoT inevitably lose data due to wireless signal strength. This data loss has contributed to increased system instability due to misinformation based on incorrect data. In this study, I designed a distributed MQTT IoT smart sensor and gateway structure that supports wireless multicasting for smooth sensor data collection. Through this, it was possible to derive significant results in the service latency and data loss rate of packets even in a wireless environment, unlike the MQTT QoS-based system. Therefore, through this study, it will be possible to implement a data collection management system optimized for the domestic smart factory manufacturing environment that can prevent data loss and delay due to abnormal data generation and minimize the input of management personnel.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.429-432
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• 2007

For smart structure technologies, the interests in wireless sensor networks for structural health monitoring are growing. The wireless sensor networks reduce the installation of the wire embedded in the whole structure and save the costs. But the wireless sensor networks have lots of limits and there are lots of researches and developments of wireless sensor and the network for data process. Most of the researches of wireless sensor network is applying to the civil engineering structure and the researches for the highrise building are required. And strain-based SHM gives the local damage information of the structures which acceleration-based SHM can not. In this paper, concept of wireless sensor network for structural health monitoring of highrise building is suggested. And verifying the feasibility of the strain-based SHM a strain sensor board has developed and tested by experiments.