• Smart Structures and Systems
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• 제6권5_6호
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• pp.731-748
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• 2010

Impact detection and health monitoring are very important tasks for civil infrastructures, such as bridges. Piezoceramic based transducers are widely researched for these tasks due to the piezoceramic material's inherent advantages of dual sensing and actuation ability, which enables the active sensing method for structural health monitoring with a network of piezoceramic transducers. Wireless sensor networks, which are easy for deployment, have great potential in health monitoring systems for large civil infrastructures to identify early-age damages. However, most commercial wireless sensor networks are general purpose and may not be optimized for a network of piezoceramic based transducers. Wireless networks of piezoceramic transducers for active sensing have special requirements, such as relatively high sampling rate (at a few-thousand Hz), incorporation of an amplifier for the piezoceramic element for actuation, and low energy consumption for actuation. In this paper, a wireless network is specially designed for piezoceramic transducers to implement impact detection and active sensing for structural health monitoring. A power efficient embedded system is designed to form the wireless sensor network that is capable of high sampling rate. A 32 bit RISC wireless microcontroller is chosen as the main processor. Detailed design of the hardware system and software system of the wireless sensor network is presented in this paper. To verify the functionality of the wireless sensor network, it is deployed on a two-story concrete frame with embedded piezoceramic transducers, and the active sensing property of piezoceramic material is used to detect the damage in the structure. Experimental results show that the wireless sensor network can effectively implement active sensing and impact detection with high sampling rate while maintaining low power consumption by performing offline data processing and minimizing wireless communication.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1221-1226
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• 2015

This paper proposes a multiple switch mode power supply (SMPS) system based on the wireless network which controls variable load. The system enables power supply of up to 600W using 200W SMPS as a unit module and provides a controlling function of output power based on variable load and a monitoring function based on wireless network. The controlling function for output power measures the variation of output power and facilitates efficient power supply by controlling output power based on the measured variation value. The monitoring function guarantees a stable power supply by observing the multiple SMPS system in real time via wireless network. The performance of the proposed system was examined by various experiments. In addition, it was verified through standardized test of Korea Testing Certification. The results were given and discussed.

• Journal of information and communication convergence engineering
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• 제4권2호
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• pp.67-70
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• 2006

A distributed healthcare monitoring system prototype for clinical and trauma patients was developed, using wireless sensor network node. The proposed system aimed to measure various vital physiological health parameters like ECG and body temperature of patients and elderly persons, and transfer his/her health status wirelessly in Ad-hoc network to remote base station which was connected to doctor's PDA/PC or to a hospital's main Server using wireless sensor node. The system also aims to save the cost of healthcare facility for patients and the operating power of the system because sensor network is deployed widely and the distance from sensor to base station was shorter than in general centralized system. The wireless data communication will follow IEEE 802.15.4 frequency communication with ad-hoc routing thus enabling every motes attached to patients, to form a wireless data network to send data to base-station, providing mobility and convenience to the users in home environment.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2002년도 춘계학술대회 논문집
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• pp.69-75
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• 2002

본 논문에서는 SNMP를 이용하여 네크워크 트래픽을 실시간으로 모니터링하는 시스템을 제안하였다. 제안된 시스템은 네트워크 정보를 수집하여 분석하고, 실시간 모니터 링을 지원하는 분석 서버 시스템과 분석된 결과를 그래픽적으로 보여주는 클라이언트 시스템으로 구성된다. 분석 서버 시스템은 클라이언트 시스템의 분석 요구에 따라 네트워크 트래픽의 정보를 수집하여 분석하고 응답한다. 클라이언트 시스템은 사용자의 관리요청에 대한 사용자 인터페이스 기능과 분석된 결과를 출력하는 기능이 있으며, 실제 네트워크 상에서의 활용성을 높이기 위해 웹 기반 기술을 적용하였다. 제안된 시스템은 사용자가 웹을 통해 네트워크 상의 관리 행위를 효과적으로 수행할 수 있도록 도움을 줄 것이다.

• 한국IT서비스학회지
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• 제14권1호
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• pp.159-173
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• 2015

This paper presents a study on the Internet of Things based low-power wireless sensor networks for remote monitoring of wildlife ecosystem due to climate change. Especially, it is targeting the wild vegetation communities ecological monitoring. First, we performed a pre-test and analysis for selecting the appropriate frequency for the sensor network to collect and deliver information reliably in harsh propagation environment of the forest area, and selected for sensors for monitoring wild vegetation communities on the basis of considerations for selecting the best sensor. In addition, we have presented the platform concept and hierarchical function structures for effectively monitoring, analyzing and predicting of ecosystem changes, to apply the Internet of Things in the ecological monitoring area. Based on this, this paper presents the system architecture and design of the Internet of Things based low-power wireless sensor networks for monitoring the ecosystem of the wild vegetation communities. Finally, we constructed and operated the test-bed applied to real wild trees, using the developed prototype based on the design.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.50-60
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• 2007

The endeavor of this paper focuses on designing a monitoring system to provide a cost-effective solution on quality assurance for construction projects. The construction site monitoring system integrates a long-range wireless network, network cameras, and a web-based collaborative platform. The users of the system could obtain the most updated status of construction sites, such as behaviors of workers, project progress, and site events anywhere with Internet connectivity. It was carefully configured in order to maintain the reliability under the reactive conditions of the construction sites. This paper reports the architecture of the monitoring system and reviews the related technologies. The system has been implemented and tested on a construction site and promising results were obtained.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.545-550
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• 2004

Recent natural disasters like flooding and slope collapse have shown the need for natural risk management system, as they endanger directly public health and cause severe damages on the national economy. In order to improve the efficiency of risk management systems, this management system based on AANN(Auto-Associative Neural Network)is proposed in this paper. AANN can be effectively used for identification of abnormal data and data compression. The proposed AANN-based risk management system collects and stores measurement data from sensors and transmits them to remote server for web-monitoring. Generally, it is desirable to transmit the compressed data instead of raw data in normal state. However, if dangerous situation happens, rapid tramission of measurement data should be required. These requirements are easily satisfied by using AANN. In order to verify the feasibilities of the proposed system, The AANN-based risk management system is applied to slope collapse monitoring system.

• 전기학회논문지
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• 제61권6호
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• pp.838-844
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• 2012

This paper proposes the effective monitoring method for marine engine system, which is implemented based upon Controller Area Network (CAN). As the marine engine monitoring system requires various kind of information, a lot of sensor nodes are distributed to several places. The CAN supports huge numbers of message IDs for the sensor nodes and provides a stable communication channel in a wide area such as a 12,000 TEU container ship. Since the CAN is priority-based communication system, some of hard real-time messages like alarm messages which are time-critical to the operation of the vessel cannot be communicated within the dead-time. Therefore it is desirable to distinguish the bandwidth of the CAN for static state messages and transition-state messages not to be harmful to the engine operations. Using the features of message arbitration ability of the CAN, it is proposed in this paper that the bandwidth allocation is dynamically adjusted to cope with the increment of input signal to improve the performance of monitoring system. Effectiveness and validity of the proposed scheme have been demonstrated through real experiments.

• 한국지능시스템학회논문지
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• 제14권1호
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• pp.1-8
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• 2004

본 논문에서는 실내대기 가스모니터링 시스템에서의 센서 고장 진단을 위한 신경회로망 기반 고장진단방법을 제안한다. 제안한 고장진단 방법에서는 신호패턴추출을 위해 센서히터 온도조절방법을 이용하였으며, 분류를 위해서는 ART2 신경회로망을 이용하였다. 그리고 가스모니터링 시스템의 실제 데이터를 이용한 시뮬레이션을 통해 제안한 ART2 신경회로망 기반 센서고장진단방법의 성능과 유용성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.472-477
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• 2013

An internet-based, real-time GPS synchronized wide-area power system frequency monitoring network(FNET) has been monitoring wide-area power system frequency in continuous time in the United States. This paper analyzes the FNET measurement to the verified disturbances in the US eastern interconnected power system and simulates it using the dynamic system model. By comparing the frequency measurements with its simulation results to the same disturbances in detail, this paper finds that the sequence of monitoring points to detect the frequency fluctuation caused by the disturbances is matched well in the measured data and the simulation results. The similarity comparison index is also proposed to quantify the similarity of the compared cases. The dynamic model based simulation result is expected to compensate for the lack of FNET measurement in its applications.