• Development and Reproduction
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• v.22 no.4
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• pp.309-318
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• 2018

The present study was conducted to investigate the regulatory mechanism of plasminogen activators (PAs) activation by $17{\beta}$-estradiol ($E_2$) and progesterone ($P_4$) in porcine uterine epithelial cells (pUECs). pUECs were collected from porcine uterine horn and cultured at 80% confluence. Then, 0.1% (v/v) DMSO, 20 ng/mL $E_2$, and $P_4$ with or without fetal bovine serum (FBS) treated to cultured cells for 24 hours. The supernatants were used for measurement of PAs activity and expression of urokinase-type PA (uPA), tissue-type PA (tPA), uPA specific receptor (uPAR), and type-1 PA inhibitor (PAI-1) mRNA were analyzed by real-time PCR. The expression of PAs-related genes was not affect by steroid hormones in both of serum treatment groups. However, PAs activity was increased by treatment of $E_2$ compared to 0.1% DMSO treatment in serum-free group (p<0.05). Then, $E_2$ and $P_4$ were diluted with 0.002% (v/v) DMSO for reduction of its effect and treated to cultured cells without FBS. Only tPA mRNA was significantly increased by $E_2$ treatment (p<0.05). PAs activity was enhanced in $E_2$ treated group compared to control groups (p<0.05). These results indicate that serum-free condition is more proper to evaluate effect of steroid hormones and activation of PAs in pUECs was mainly regulated by estrogen. These regulation of PAs activation may be associated with uterine remodeling during pre-ovulatory phase in pigs, however, further studies are needed to investigate precise regulatory mechanism.

• Smart Structures and Systems
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• v.15 no.1
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• pp.99-117
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• 2015

The Stonecutters Bridge (SCB) in Hong Kong is the third-longest cable-stayed bridge in the world with a main span stretching 1,018 m between two 298 m high single-leg tapering composite towers. A Wind and Structural Health Monitoring System (WASHMS) is being implemented on SCB by the Highways Department of The Hong Kong SAR Government, and the SCB-WASHMS is composed of more than 1,300 sensors in 15 types. In order to establish a linkage between structural health monitoring and maintenance management, a Structural Health Rating System (SHRS) with relevant rating tools and indices is devised. On the basis of a 3D space frame finite element model (FEM) of SCB and model updating, this paper presents the development of an SHR-oriented 3D multi-scale FEM for the purpose of load-resistance analysis and damage evaluation in structural element level, including modeling, refinement and validation of the multi-scale FEM. The refined 3D structural segments at deck and towers are established in critical segment positions corresponding to maximum cable forces. The components in the critical segment region are modeled as a full 3D FEM and fitted into the 3D space frame FEM. The boundary conditions between beam and shell elements are performed conforming to equivalent stiffness, effective mass and compatibility of deformation. The 3D multi-scale FEM is verified by the in-situ measured dynamic characteristics and static response. A good agreement between the FEM and measurement results indicates that the 3D multi-scale FEM is precise and efficient for WASHMS and SHRS of SCB. In addition, stress distribution and concentration of the critical segments in the 3D multi-scale FEM under temperature loads, static wind loads and equivalent seismic loads are investigated. Stress concentration elements under equivalent seismic loads exist in the anchor zone in steel/concrete beam and the anchor plate edge in steel anchor box of the towers.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1095-1109
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• 2021

The technology used to recognize the location and surroundings of autonomous vehicles is called SLAM. SLAM standsfor Simultaneously Localization and Mapping and hasrecently been actively utilized in research on autonomous vehicles,starting with robotic research. Expensive GPS, INS, LiDAR, RADAR, and Wheel Odometry allow precise magnetic positioning and mapping in centimeters. However, if it can secure similar accuracy as using cheaper Cameras and GPS data, it will contribute to advancing the era of autonomous driving. In this paper, we present a method for converging monocular camera with RTK-enabled GPS data to perform RMSE 33.7 cm localization and mapping on the urban road.

• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.302-307
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• 2019

In modern Anti-Submarine Warfare, there are various ways to locate a submarine in a two-dimensional space. For more effective tracking and attack against a submarine the depth of the target is a critical factor. However, it has been difficult to find out the depth of a submarine until now. In this paper a possible solution to the depth estimation of submarines is proposed utilizing DIFAR (Directional Frequency Analysis and Recording) sonobuoy information such as contact bearings at or prior to CPA (Closest Point of Approach) and the target's Doppler signals. The relative depth of the target is determined by applying the Pythagorean theorem to the slant range and horizontal range between the target and the hydrophone of a DIFAR sonobuoy. The slant range is calculated using the Doppler shift and the target's velocity. the horizontal range can be obtained by applying a simple trigonometric function for two consecutive contact bearings and the travel distance of the target. The simulation results show that the algorithm is subject to an elevation angle, which is determined by the relative depth and horizontal distance between the sonobuoy and target, and that a precise measurement of the Doppler shift is crucial.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.340-345
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• 2020

In this study, we developed the quality control and assurance method of measurement data of SPAR (Soil-Plant-Atmosphere-Research) system, a climate change research facility, for the first time. It was found that the precise processing of CO2 flux data among many observations were sig nificantly important to increase the accuracy of canopy photosynthesis measurements in the SPAR system. The collected raw CO2 flux data should first be removed error and missing data and then replaced with estimated data according to photosynthetic lig ht response curve model. Comparing the correlation between cumulative net assimilation and soybean biomass, the quality control and assurance of the raw CO2 flux data showed an improved effect on canopy photosynthesis evaluation by increasing the coefficient of determination (R2) and lowering the root mean square error (RMSE). These data processing methods are expected to be usefully applied to the development of crop growth model using SPAR system.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.2
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• pp.80-85
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• 2020

Recently the incidence of musculoskeletal disorders in students and office workers is increasing, and the necessity of maintaining correct posture and corrective training is required, but related research is insufficient. In the previous study, a membrane sensor or a pressure sensor was placed on the seat cushion to see the deviation of the body weight, or a sensor that restrained the user was attached to measure the position change. In this study, a sensor device for detecting a position change in consideration of wearing comfort was developed, and the measured angle was verified through an analysis app. A sensor device consisting of an IMU sensor is attached to the cervical spine and vertebra spine to measure the position transformation in the sitting position. The change value of the position measured by the two sensors was converted into an angle, and the angle value is displayed in real time through the analysis app. In this study, the possibility of measuring the real-time change value according to the change in position, the convenience of wearing, and the tendency of angle measurement were proved. Future research should proceed with more precise angle calculation and correction of motion noise.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.4
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• pp.553-559
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• 2020

Seaweed(Laver), Korea's largest export product, is currently focused on mass production due to the market situation in Korea. This naturally led to a decrease in the quality of seaweed. Therefore, in this paper, the present method was produced and tested by changing the way of adjusting the ratio of seaweed mixing, which was dependent on the user's sense and experience in the production of seaweed. In addition, I developed an embedded measurement system that can determine the concentration of a mixture of gold in real time based on primary image information obtained through an IR LED lamp that generates a light source and a photo sensor that detects concentration. By collecting and storing precise data in real time, it is easier to cope with the previous year's data in a work environment that is repeated every winter.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.599-606
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• 2021

Water Distribution Networks, one of the social infrastructures buried underground, has the function of transporting and supplying purified water to customers. In recent years, as measurement capability is improved, a number of studies related to leak recognition and detection by applying a deep learning technique based on flow rate data have been conducted. In this study, a cognitive model for leak occurrence was developed using an LSTM-based deep learning algorithm that has not been applied to the waterworks field until now. The model was verified based on the assumed data, and it was found that all cases of leaks of 2% or more can be recognized. In the future, based on the proposed model, it is believed that more precise results can be derived in the prediction of flow data.

• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.250-254
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• 2021

A highly sensitive and selective non-dispersive infrared (NDIR) carbon dioxide gas sensor requires achieving high transmittance and narrow full width at half maximum (FWHM), which depends on the interface of the optical filter for precise measurement of carbon dioxide concentration. This paper presents the design, simulation, and fabrication of a Fabry-Perot filter based on a distributed Bragg reflector (DBR) for a low-cost NDIR carbon dioxide sensor. The Fabry-Perot filter consists of upper and lower DBR pairs, which comprise multilayered stacks of alternating high- and low-index thin films, and a cavity layer for the resonance of incident light. As the number of DBR pairs inside the reflector increases, the FWHM of the transmitted light becomes narrower, but the transmittance of light decreases substantially. Therefore, it is essential to analyze the relationship between the FWHM and transmittance according to the number of DBR pairs. The DBR is made of silicon and silicon dioxide by RF magnetron sputtering on a glass wafer. After the optimal conditions based on simulation results were realized, the DBR exhibited a light transmittance of 38.5% at 4.26 ㎛ and an FWHM of 158 nm. The improved results substantiate the advantages of the low-cost and minimized process compared to expensive commercial filters.

• Geomechanics and Engineering
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• v.27 no.5
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• pp.433-445
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• 2021

Artificial ground freezing (AGF) is a commonly used geotechnical support technique that can be applied in any soil type and has low environmental impact. Experimental and numerical investigations have been conducted to optimize AGF for application in diverse scenarios. Precise simulation of groundwater flow is crucial to improving the reliability these investigations' results. Previous experimental research has mostly considered horizontal seepage flow, which does not allow accurate calculation of the groundwater flow velocity due to spatial variation of the piezometric head. This study adopted vertical seepage flow-which can maintain a constant cross-sectional area-to eliminate the limitations of using horizontal seepage flow. The closure time is a measure of the time taken for an impermeable layer to begin to form, this being the time for a frozen soil-ice wall to start forming adjacent to the freeze pipes; this is of great importance to applied AGF. This study reports verification of the reliability of our experimental apparatus and measurement system using only water, because temperature data could be measured while freezing was observed visually. Subsequent experimental AFG tests with saturated sandy soil were also performed. From the experimental results, a method of estimating closure time is proposed using the inflection point in the thermal conductivity difference between pore water and pore ice. It is expected that this estimation method will be highly applicable in the field. A further parametric study assessed factors influencing the closure time using a two-dimensional coupled thermo-hydraulic numerical analysis model that can simulate the AGF of saturated sandy soil considering groundwater flow. It shows that the closure time is affected by factors such as hydraulic gradient, unfrozen permeability, particle thermal conductivity, and freezing temperature. Among these factors, changes in the unfrozen permeability and particle thermal conductivity have less effect on the formation of frozen soil-ice walls when the freezing temperature is sufficiently low.