• Smart Structures and Systems
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• v.11 no.5
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• pp.533-553
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• 2013

In this paper, system identification of a cable-stayed bridge in Korea, the Hwamyung Bridge, is performed using vibration responses measured by a wireless sensor system. First, an acceleration based-wireless sensor system is employed for the structural health monitoring of the bridge, and wireless sensor nodes are deployed on a deck, a pylon and several selected cables. Second, modal parameters of the bridge are obtained both from measured vibration responses and finite element (FE) analysis. Frequency domain decomposition and stochastic subspace identification methods are used to obtain the modal parameters from the measured vibration responses. The FE model of the bridge is established using commercial FE software package. Third, structural properties of the bridge are updated using a modal sensitivity-based method. The updating work improves the accuracy of the FE model so that structural behaviors of the bridge can be represented better using the updated FE model. Finally, cable forces of the selected cables are also identified and compared with both design and lift-off test values.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.45-47
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• 2009

Wireless Sensor Network(WSN) has been very popular in unattended surveillance systems recently. For Applying WSN into Building Automation system(BAS), a novel hierarchial network structure and static routing algorithm which eliminates the scalability limitation of Zigbee are proposed in this paper. The static routing algorithm relying on the hierarchial network address reduces the computational complexity to a great extent and has a real-time performance which satisfies urgent applications well.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.465-468
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• 2003

In industry areas, a lot of factories and process plants need network for processing data acquired from field and for communicating between sensors or actuators or field controllers. Most of the industry networks are based on wired solutions. But, recently, a lot of factories and process plants are moving into wireless solutions since they have some advantages compared with wired one. In this paper we first review the characteristics of wired and wireless network technologies and introduce the new technique called wireless sensor network (WSN). And then we describe the wireless sensor node system designed by us for WSN which has the ability of small size, flexibility and low-power consumption and embedded into the Bar-code scanner to communicate each other. Finally, we conclude this paper by showing that wireless industry network can be constructed with wireless sensor network without large change of traditional wired topologies through experiment using wireless sensor nodes.

• Journal of information and communication convergence engineering
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• v.17 no.2
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• pp.105-116
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• 2019

Recently, there has been an increase in research on wireless sensor networks (WSNs) because they are easy to deploy in applications such as internet-of-things (IoT) and body area networks. However, WSNs have constraints in terms of power, quality-of-service (QoS), computation, and others. To overcome the power constraint issues, wireless energy harvesting has been introduced into WSNs, the application of which has been the focus of many studies. Additionally, to improve system performance in terms of achievable rate, cooperative networks are also being explored in WSNs. We present a review on current research in the area of energy harvesting in WSNs, specifically on the application of simultaneous wireless information and power transfer (SWIPT) in a cooperative sensor network. In addition, we discuss possible future extensions of SWIPT and cooperative networks in WSNs.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.143-151
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• 2016

In this paper, a real-time air quality monitoring system based on wireless network is designed and implemented for industrial park or multiuse facilities. The existing gas detector is high price and hard to apply the remote monitoring system. On the other hand, demand for air quality monitoring is increasing because of industrial gas accident, air pollution, and so on. In Korea, indoor air regulation was established by law. According to indoor air regulation, CO2, CO, and NO2 are important gases as the air quality standard. So we study the gas detector for indoor air quality and the wireless network system. The wireless network consist of sensor network and WCDMA to apply various place. To verify the performance of the implemented gas detector, the gas measurement experiment is performed in laboratory environment by using the realized gas detecting wireless sensor node. And we evaluate the experiment results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.518-521
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• 2007

The functional wireless sensor node for u-healthcare application was developed. The developed sensor node can check the abnormality of ECG in some simple software in ROM of microprocess in the sensor node. The ECG signal is one of very important health signal form human body, and wavelike signal which is sampled as a sampling frequency between 100 and 400 Hz for digitalization, so the wireless data dor ECG signal is some heavy in Zigbee communication. Thus the sensor send the ECG signal to other sensor nodes or base station when it find abnormality in ECG signal is key technology to reduce the traffic between sensor nodes in wireless sensor network for u-healthcare, The sensor node does not need to transmit ECG data all time in wireless sensor network and to server. Using these sensor nodes, the healthcare system can dramatically reduce wireless data packet overload, the power consumption of battery in the sensor nodes and thus increase the reliability of the wireless system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.96-102
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• 2011

There are many problems with the fire detection devices being used in currently, because it is difficult to find location of the source of fire and determine where devices are working or not. In this paper, we proposed fire detection and rescue system using wireless sensor network that can be real-time monitoring and determine safe exit. Fire detection and rescue system based on ubiquitous sensor network can know exactly source of fire and help determine rescue tactics using sensing data from wireless sensor nodes. Transmitted wirelessly in real-time thermal sensor and gas sensor information to analyze the GUI to monitor the status information output to the screen by use of a system implemented in everyday life, looked at the possibility.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.43-51
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• 2011

Irrigation facilities are spread over demand area in a low density and exposed in the field requiring efficient operation and maintenance. Thus, it could be more efficient to manage an irrigation system when it is with wireless sensor network (WSN) using RFID (Radio Frequency Identification) application. A WSN, a kind of ubiquitous sensor network composed of wireless network, RFID and database management system was developed for agricultural water management in terms of operational status and maintenance requirements. Identification code for RFID tag was designed and an application for RFID reader was developed for field data collection, and a database management system was constructed for managing irrigation facility attributes. The system was installed in I-dong irrigation districts in Gyounggi-province, Korea and the operated results showed the applicability of the WSN for agricultural water management.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.821-822
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• 2006

Ubiquitous healthcare monitoring and measuring system based on wireless sensor network was implemented and tested. The system can measure the ECG and body temperature of patients or elderly persons and transfer the data wirelessly in ad-hoc network to remote base-station connected to doctor's PDA/PC or hospital server, using wireless sensor motes. The data obtained can be analyzed by doctors and care providers to monitor a health status of patient in real time environment. To prove the capabilities of the wireless sensor network platform for ubiquitous healthcare applications, the performance of our monitoring and measuring system was tested with positive results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.127-132
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• 2008

As economic rapid growth, large structures are damaged by defects from design and construction process of the formation and environments. Therefore, safety diagnosis and monitoring skills are bringing importance into relief and legislate for safety diagnosis of large structures. However, the existing monitoring systems are difficult by using wire cable because of cost, error of date, location, revise. In this paper, wireless sensor network which are accelerator, temperature sensor system using ubiquitous had been field test on Sea-Hea Grand bridge. We compare accelerator, temperature sensor system with wire and wireless sensor network.