• Smart Structures and Systems
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• v.6 no.5_6
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• pp.689-709
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• 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.

• Journal of Environmental Science International
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• v.31 no.7
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• pp.555-567
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• 2022

With the introduction of the tele-monitoring system (TMS) in South Korea, monitoring of the concentration of pollutants discharged from nationwide water quality TMS attachments is possible. In addition, the Ministry of Environment is implementing a smart sewage system program that combines ICT technology with wastewater treatment plants. Thus, many institutions are adopting the automatic operation technique which uses process operation factors and TMS data of sewage treatment plants. As a part of the preliminary study, a multilayer perceptron (MLP) analysis method was applied to TMS data to identify predictability degree. TMS data were designated as independent variables, and each pollutant was considered as an independent variables. To verify the validity of the prediction, root mean square error analysis was conducted. TMS data from two public sewage treatment plants in Chungnam were used. The values of RMSE in SS, T-N, and COD predictions (excluding T-P) in treatment plant A showed an error range of 10%, and in the case of treatment plant B, all items showed an error exceeding 20%. If the total amount of data used MLP analysis increases, the predictability of MLP analysis is expected to increase further.

• 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.

• Membrane and Water Treatment
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• v.14 no.4
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• pp.155-162
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• 2023

Global climate change and urbanization have various demerits, such as water pollution, flood damage, and deterioration of water circulation. Thus, attention is drawn to Nature-based Solution (NbS) that solve environmental problems in ways that imitate nature. Among the NbS, urban wetlands are facilities that perform functions, such as removing pollutants from a city, improving water circulation, and providing ecological habitats, by strengthening original natural wetland pillars. Frequent monitoring and maintenance are essential for urban wetlands to maintain their performance; therefore, there is a need to apply the Internet of Things (IoT) technology to wetland monitoring. Therefore, in this study, we attempted to develop a real-time wetland monitoring device and interface. Temperature, water temperature, humidity, soil humidity, PM1, PM2.5, and PM10 were measured, and the measurements were taken at 10-minute intervals for three days in both indoor and wetland. Sensors suitable for conditions that needed to be measured and an Arduino MEGA 2560 were connected to enable sensing, and communication modules were connected to transmit data to real-time databases. The transmitted data were displayed on a developed web page. The data measured to verify the monitoring device were compared with data from the Korea meteorological administration and the Korea environment corporation, and the output and upward or downward trend were similar. Moreover, findings from a related patent search indicated that there are a minimal number of instances where information and communication technology (ICT) has been applied in wetland contexts. Hence, it is essential to consider further research, development, and implementation of ICT to address this gap. The results of this study could be the basis for time-series data analysis research using automation, machine learning, or deep learning in urban wetland maintenance.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.138-140
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• 2001

The Earth, along with its major components - land, atmosphere, and oceans, is at the core of the global environmental system. Changes in any component of the Earth thus strongly affect the global and regional environment. With the advent of the new century, many important decisions on agricultural, industrial, societal and political problems will depend upon the Earth's environment. Monitoring the Earth is thus important to capture any sign from the Earth which might be related to the environmental change. (omitted)

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.417-420
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• 2004

Recently, the applications of unmanned system are steadily increasing. Unmanned automatic system is suitable for routine mission such as reconnaissance, environment monitoring, resource conservation and investigation. Especially, for the ocean environment monitoring mission, many ocean engineers had scoped with the routine and even risky works. The automatic system can replace the periodic and routine missions: water sampling, temperature and salinity measuring, etc. In this paper, an unmanned surface vessel was designed for routine and periodic ocean environmental missions. An autonomous control system was designed and tested for the unmanned vessel. A GPS and gyro compass was used for navigation. A linear autopilot model for course control can be derived from the maneuvering model. Nomoto's 2nd-order response equation was derived. The design methodologies and performance of the surface vessel were illustrated and verified with this linearized equation of motion. A linear controller was designed and automatic route tracking performance was verified for yaw subsystem.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1765-1767
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• 2005

This paper proposes central monitoring system(PVCMS) based on a TCP/IP network for effective integrating management about photovoltaic systems. We don't gain confidence the result of production simulation, because the output of PV system have many various environmental change factor. So if we can obtain real operated data about each sites and system types to use PVCMS, we can define the environment change factor to compare with simulation data. And this paper try to access about total management and data analysis methods of renewable energy through results analysis to synthesize of the operation.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.6
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• pp.71-80
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• 2016

Along with the increase in the standard of living, the interest and awareness level of the public about environmental issues have also gradually increased. Recently, time spent on indoor activities have increased and the need for awareness and demand on methods in improving the quality of an indoor environment has been recognized. The purpose of this study is to sense the environment information through real-time monitoring of the room environment by using the IoT based technology and to maintain and improve the indoor environment to an appropriate level through the developed interlocking controller device. This provides an automatic control system in improving the indoor environment at home and other small areas like general offices in place of the traditional passive interior environmental improvement actions or large-scale facility control system. A status analysis with the relative reference values of the air quality and CO2, temperature and humidity and illumination and noise was applied through transmitting a control signal to automatic control module in accordance with the nine indoor environment standards set to improve the indoor environment.

• Coupled systems mechanics
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• v.5 no.2
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• pp.191-201
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• 2016

Coupled structures are widely seen in civil and mechanical engineering. In coupled structures, monitoring the translational motion of its key components is of great importance. For instance, some coupled arms are equipped with a hydraulic piston to provide the stiffness along the piston axial direction. The piston moves back and forth and a distance sensing system is necessary to make sure that the piston is within its stroke limit. The measured motion data also give us insight into how the coupled structure works and provides information for the design optimization. This paper develops two distance sensing systems for coupled structures. The first system measures distance with ultrasonic sensor. It consists of an ultrasonic sensing module, an Arduino interface board and a control computer. The system is then further upgraded to a three-sensor version, which can measure three different sets of distance data at the same time. The three modules are synchronized by the Arduino interface board as well as the self-developed software. Each ultrasonic sensor transmits high frequency ultrasonic waves from its transmitting unit and evaluates the echo received back by the receiving unit. From the measured time interval between sending the signal and receiving the echo, the distance to an object is determined. The second distance sensing system consists of a wire draw encoder, a data collection board and the control computer. Wire draw encoder is an electromechanical device to monitor linear motion by converting a central shaft rotation into electronic pulses of the encoder. Encoder can measure displacement, velocity and acceleration simultaneously and send the measured data to the control computer via the data acquisition board. From experimental results, it is concluded that both the ultrasonic and the wire draw encoder systems can obtain the linear motion of structures in real-time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1687-1692
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• 2019

In the era of the fourth industrial revolution, advanced technologies such as the Internet of Things(IoT) and big data are emerging. However, the level of application of IoT to indoor environment is very weak. Therefore, it is necessary to develop a system for analyzing air pollutants or indoor air quality through real-time monitoring using the IoT. This paper implements a system that measures indoor environmental values using Arduino and various sensors, and stores the information obtained from various sensors into a database of server. The information stored in the server was built as a database and utilized in the ventilation system or air cleaner installed in the home or company's room. In the proposed system, it is possible to check the immediate indoor environmental condition through the LED status display of the monitoring sensor module while reducing the cost of the sensor used to implement IoT technology.