• Smart Structures and Systems
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• v.21 no.2
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• pp.171-185
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• 2018

Maintenance of deteriorated bridge structures has always been one of the challenging issues in developing countries as it is directly related to daily life of people including trade and economy. An effective maintenance strategy is highly dependent on timely inspections on the bridge health condition. This study is intended to investigate an approach for detecting bridge damage for the long-term health monitoring by use of copula theory. Long-term measured data for the seven-span plate-Gerber bridge is investigated. Autoregressive time series models constructed for the observed accelerations taken from the bridge are utilized for the computation of damage indicator for the bridge. The copula model is used to analyze the statistical changes associated with the modal parameters. The changes in the modal parameters with the time are identified by the copula statistical properties. Applicability of the proposed method is also discussed based on a comparison study among other approaches.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.85.4-85.4
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• 2019

Supernovae (SNe) are well known as good cosmological distance probes owing to their brightness and well-characterized light curve property. Specifically, type Ia SNe have contributed greatly to our understanding of acceleration of cosmic expansion. However, type IIP supernovae occur most frequently (~ 40% of all) at low and high redshift. As knowledge on the type IIP SNe increases, distance measurement methods using type IIP SNe have evolved. In this study, we apply Photometric Color Method (PCM), which needs only photometric data using properties of plateau on type IIP SNe light curves, to measure distances of several host galaxies of SNe IIP from the Intensive Monitoring Survey of Nearby Galaxies (IMSNG). The daily monitoring of galaxies at < 50 Mpc allows us to construct a dense light curve of SNe that occurred in our target galaxies. We observed two SNe IIP, SN2014cx and SN2017eaw and measured distances to their host galaxies, NGC 337 and NGC6946 respectively. Our results are comparable with other secondary distance measurement methods, 4-5 Mpc, however smaller than the result derived from the Tip of Red Giant Branch (TRGB) method, $6.7{\pm}0.2$ and $7.7{\pm}0.3Mpc$.

• Journal of the Korean Electrochemical Society
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• v.25 no.1
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• pp.13-21
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• 2022

There is an increasing interest in monitoring of specific biomarker for determining progression of a disease or efficacy of a treatment. Conventional method for quantification of specific biomarkers as enzyme linked immunosorbent assay (ELISA) has high material costs, long incubation periods, requires large volume of samples and involves special instruments, which necessitates clinical samples to be sent to a lab. This paper reports on the development of an electrochemical biosensor to measure total immunoglobulin E (IgE), a marker of asthma disease that varies with age, gender, and disease in concentrations from 0.3-1000 ng/mL with consuming 20 µL volume of whole blood sample. The sensor provides rapid, accurate, easy, point-of-care measurement of IgE, also, sequential monitoring of total IgE with ovalbumin (OVA) induced mice is another application of sensor. Taken together, these results provide an alternative way for detection of biomarkers in whole blood with low volumes and long-term ex-vivo assessments for understanding the progression of a disease.

• Journal of muscle and joint health
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• v.29 no.1
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• pp.50-59
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• 2022

Purpose: This qualitative study aimed to explore the experiences of patients with diabetes provided with medication monitoring using an artificial intelligence-based smartwatch. Methods: Giorgi's descriptive phenomenological methodology was applied to collect and analyze data from November 9 to December 23, 2021. The study samples were recruited by convenience sampling, and even patients with diabetes participated in in-depth interviews via video conference and telephone calls or face-to-face visits. Results: Ten sub-themes and four themes were finally revealed. The four themes were as follows: journey with unfamiliar devices, a less-than-acceptable smartwatch, insufficient functions and content for patients with diabetes to use, and efforts for regular medication behaviors and daily monitoring of patient's health conditions. Conclusion: To effectively manage diabetic conditions using digital healthcare technologies, nursing interventions were needed to identify personal needs and consider technological, psychological, aesthetic, and socioeconomic aspects of wearable devices.

• Smart Structures and Systems
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• v.30 no.6
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• pp.557-569
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• 2022

Vibration-based structural health monitoring (SHM) is crucial for the dynamic maintenance of civil building structures to protect property security and the lives of the public. Analyzing these vibrations with modern artificial intelligence and deep learning (DL) methods is a new trend. This paper proposed an unsupervised deep learning method based on a convolutional autoencoder (CAE), which can overcome the limitations of conventional supervised deep learning. With the convolutional core applied to the DL network, the method can extract features self-adaptively and efficiently. The effectiveness of the method in detecting damage is then tested using a benchmark model. Thereafter, this method is used to detect damage and instant disaster events in a rubber bearing-isolated gymnasium structure. The results indicate that the method enables the CAE network to learn the intact vibrations, so as to distinguish between different damage states of the benchmark model, and the outcome meets the high-dimensional data distribution characteristics visualized by the t-SNE method. Besides, the CAE-based network trained with daily vibrations of the isolating layer in the gymnasium can precisely recover newly collected vibration and detect the occurrence of the ground motion. The proposed method is effective at identifying nonlinear variations in the dynamic responses and has the potential to be used for structural condition assessment and safety warning.

• Proceedings of the KSCN Conference
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• 2005.10a
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• pp.103-103
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• 2005

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.860-870
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• 2010

Long term monthly monitoring data showed that the water quality of streams flowing into Lake Paldang has been improved by various strategy for water. However, the effect of quality on Lake Paldang is still insufficient because of nonpoint source from watershed. In order to evaluate quantifying methods for pollution source and make a suggestion on improvements, Storm Water Management Model (SWMM) was constructed by using data set from the water quality and streamflow monitoring network in the Kyoungan watershed for Total Maximum Daily Loads (TMDLs). Load duration curve (LDC) based on the result of the Kyoungan watershed SWMM indicated that the water quality criterion on $BOD_5$ was often exceeded in up-stream than down-stream. From flowrate-load correlation curve, SS load significantly increased as streamflow increases. 75.3% of streamflow and 62.1% of $BOD_5$ loads is discharged especially in the zone of high flows, but monitoring data set didn't provide proper information about the conditions and the patterns associated with storm events. Therefore, it is necessary to acquire representative data set for comparing hydrograph and pollutograph through monitoring experimental watershed and to establish methods for quantifying point and nonpoint source pollutant loads.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.758-765
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• 2016

This paper is a follow-up paper to the publication, "Development of Tunnel-Environment Monitoring System and Its Installation I - Monitoring System and Measurement in Subway Tunnel" [1]. An environment monitoring system was installed in the 20.3-km-long Gumjung tunnel, which has the general structure of a high-speed double-track railway tunnel. Data were collected for approximately one year. Monthly and daily data were obtained and analyzed for the temperature and relative humidity in summer and winter months. This paper discusses the environmental characteristics at different positions in the tunnel. The results are expected to be widely used in studies on tunnel ventilation and the improvement of air quality and thermal environments.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.129-131
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• 2015

We have initiated single-dish monitoring observations of ~400 methanol maser sources at 6.7 GHz using the Hitachi 32-m radio telescope from December 2012 to systematically research periodic flux variations, which are observed in some methanol maser sources associated with high-mass (proto-)stars. In our monitoring, we have made daily monitoring, so that each source has been observed every nine days with an integration time of 5 min (typical $3{\sigma}$ detection sensitivities of 0.9 Jy). The monitoring observations help us statistically understand periodic flux variations with a period longer than 50 days. As an initial result, we present a new detection of periodic flux variations in the 6.7 GHz methanol maser source G 036.70+00.09. The period of the flux variations is ~53 days (~0.019 cycles $day^{-1}$), and seems to be stable over 9 cycles, at least until the middle of August 2014.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.2
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• pp.35-45
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• 2023

The DOR (Drainage outlet raising) in the paddy field has been suggested as one of the most important best management practices for the TMDL (Total maximum daily load) management in the technical guidelines by the NIER (National institute of environmental research). However, this method is underestimated and is not well adopted by local governments for the TMDL. The purpose of this study is to evaluate the unit load reduction equation according to the application of DOR in order to expand this equation. The original equation in the guideline was derived using the HSPF (Hydrological Simulation Program-Fortran) model for 1 year in Changnyeong. We analyzed the reduction effect of the original equation application by collecting additional long-term monitoring data from the Buan, Icheon, Iksan, and Jeonju. When comparing the reduction loads between the original equation and monitoring results, the evaluation results of the original equation were 11% of the monitoring analysis results, which was underestimated. This means that the original equation needs to be improved. For assessing the equation, the HSPF Paddy-RCH model was established according to the NI ER guideline and evaluated for applicability. The performance results of the model showed a reasonable range by the statistical criteria. Modified equations 1 and 2 were proposed based on the monitoring and modeling results. Modified equation 1 was the method of modifying the original equation's main factors, and modified equation 2 was the method of applying the non-point pollution reduction efficiency according to the rainfall class using the long-term modeling results. At the level of 58.6~64.6% of monitoring data, the difference between them could be further reduced compared to the original equation. The suggested approach will be more reasonable and practicable for decision-makers and will contribute to the TMDL management plans.