• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.693-699
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• 2023

Ultrasound is widely used in the medical field for non-destructive and non-invasive disease diagnosis. In order to improve the disease diagnosis accuracy of diagnostic medical images, improving spatial resolution is a very important factor. In this study, we aim to model the super resolution convolutional neural network (SRCNN) algorithm in ultrasound images and analyze its applicability in the medical diagnostic field. The study was conducted as an experimental study using Field II simulation and open source clinical liver hemangioma ultrasound imaging. The proposed SRCNN algorithm was modeled so that end-to-end learning can be applied from low resolution (LR) to high resolution. As a result of the simulation, we confirmed that the full width at half maximum in the phantom image using a Field II program was improved by 41.01% compared to LR when SRCNN was used. In addition, the peak to signal to noise ratio (PSNR) and structural similarity index (SSIM) evaluation results showed that SRCNN had the excellent value in both simulated and real liver hemangioma ultrasound images. In conclusion, the applicability of SRCNN to ultrasound images has been proven, and we expected that proposed algorithm can be used in various diagnostic medical fields.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.49-62
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• 2024

Reckless development of the underground by rapid urbanization causes inspection delay on replacement of existing structure and installation new facilities. However, frequent accidents occur due to deviation in construction design planned by inaccurate location information of underground structure. Meanwhile, the electrical resistivity survey, knowns as non-destructive method, is based on the difference in the electric potential of electrodes to measure the electrical resistance of ground. This method is significantly advanced with multi-electrode and deep learning for analyzing strata. However, there is no study to quantitatively assess change in electrical resistance according to geometric conditions of structures. This study evaluates changes in electrical resistance through geometric parameters of electrodes and structure. Firstly, electrical resistance numerical module is developed using generalized mesh occurring minimal errors between theoretical and numerical resistance values. Then, changes in resistances are quantitatively compared on geometric parameters including burial depth, diameter of structure, and distance electrode and structure under steady current condition. The results show that higher electrical resistance is measured for shallow depth, larger size, and proximity to the electrode. Additionally, electric potential and current density distributions are analyzed to discuss the measured electrical resistance around the terminal electrode and structure.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.484-491
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• 2023

Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO₂ enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO₂ enrichment in greenhouse tomatoes. The growth of tomato treated with CO₂ enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO₂ was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO₂ treatment group than control. CO₂ enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.

• Journal of Conservation Science
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• v.32 no.2
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• pp.235-247
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• 2016

Conventional imaging techniques such as ultraviolet, infrared, and X-ray are used mainly to diagnose the damaged parts of the painted cultural assets in Korea. These techniques, however, have limits in diagnosing damages of interlayer parts. We have performed and extensive study on the applicability of Terahertz(THz) analysis technique, introduced recently to this field of study on cultural properties in Korea, to diagnose painted cultural assets. The specimens, produced to imitate the damage types of Korean painted properties, were analyzed over their painting, supporting, and backing layers by terahertz pulse imaging technique. The analyzed results provided information about the cracks, the separated areas, and the separated distances between layers on the specimens. Our research, then, was extended to real painted cultural remains, Birojana Sam-shin Gwebul-do at Bongseon Temple in Namyang-ju, Korea National Treasure Number 1792, through which we have obtained 3D information about the extent and pattern of damages to the asset. These results demonstrate that terahertz 3D imaging technique has the capability of noncontact 3D diagnosis on painted cultural properties.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.257-262
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• 2016

The purpose of this study was to assess the correlation between integrated mineral loss (volume % mineral${\times}{\mu}m$, ${\Delta}Z_{TMR}$) determined using transverse microradiography (TMR) and integrated reflectivity ($dB{\times}{\mu}m$, ${\Delta}R_{OCT}$) determined using optical coherence tomography (OCT) for detecting early dental caries with lesion depth more than $200{\mu}m$. Sixty tooth specimens were made from sound bovine teeth. They were immersed in a demineralized solution for 20, 30, and 40 days. The ${\Delta}R_{OCT}$ was obtained from the cross-sectional OCT image. The ${\Delta}Z_{TMR}$ was obtained from the TMR image. The correlation between ${\Delta}R_{OCT}$ and ${\Delta}Z_{TMR}$ was examined using Pearson correlation. The Bland-Altman plot was constructed using the ${\Delta}R_{OCT}$ and ${\Delta}Z_{TMR}$ values. A significant correlation between ${\Delta}R_{OCT}$ and ${\Delta}Z_{TMR}$ was confirmed (r=0.491, p=0.003). Moreover, most of the difference between ${\Delta}R_{OCT}$ and ${\Delta}Z_{TMR}$ was included in the error section of the Bland-Altman plot. Therefore, OCT could be used as a substitute for TMR when analyzing mineral loss in early dental caries.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.115-121
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• 2011

The objective of this study was to develop models to predict freshness factors (total viable counts (TVC), pH, volatile basic nitrogen (VBN), trimethylamine (TMA), and thiobarbituric acid (TBA) values) and the storage period in beef using a visible and near-infrared (NIR) spectroscopic technique. A total of 216 beef spectra were collected during the storage period from 0 to 14 d at a $10^{\circ}C$ storage. A spectrophotometer was used to measure reflectance spectra from beef samples, and beef freshness spectra were divided into a calibration set and a validation set. Multi-linear regression (MLR) models using the stepwise method were developed to predict the factors. The MLR results showed that beef freshness had a good correlation between the predicted and measured factors using the selected wavelength. The correlation of determination ($r^2$), standard error of prediction (SEP), and ratio of standard deviation to SEP (RPD) of the prediction set for TVC was 0.74, 0.64, and 2.75 Log CFU/$cm^2$, respectively. The $r^2$, SEP, and RPD values for pH were 0.43, 0.10, and 1.10; those for VBN were 0.73, 1.45, and 2.00 mg%; those for TMA were 0.70, 0.19, and 2.58 mg%; those for TBA values were 0.73, 0.13, and 2.77 mg MA/kg; and those for storage period were 0.77, 1.94, and 2.53 d, respectively. The results indicate that visible and NIR spectroscopy can predict beef freshness during storage.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.381-386
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• 2022

Non-Destruction Test (NDT) is a method to check internal defects without destroying the product. Among them, radiographic testing (RT) uses high-energy radiation, so it is very important to prevent radiation exposure of workers. Therefore, in this study, in this study, a radiation sensor structure that improves radiation detection performance compared to the existing PbI₂ and can immediately detect accidents in RT was presented. For evaluation, the conversion efficiency was analyzed in the gamma ray source through FLUKA simulation. PbI₂ with overlapping Gd₂O₂S:Tb presented in this study showed a higher radiation sensitivity from 1.22 to 3.22 times than that of non-overlapping PbI₂. This indicates that the presented sensor is suitable for use as a radiation sensor for source detection in RT.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.461-470
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• 2019

This study was carried out to quantify the drought stress in grafted watermelon seedlings non-destructively by using chlorophyll fluorescence (CF) imaging technique rather than the visual judgment. Six-day old watermelon seedlings were grown under uniform irrigation for 3 days, and then given drought stress. Afterward, the sensor for the measurement of water content in plug tray cell unit was used to classify the drought-stress level into nine groups from D1 (53.0%, sufficient moisture state) to D9 (15.7%, extremely dry stress), and the 16 CF parameters were measured. In addition, re-irrigation was performed on the drought stressed seedlings(D5 - D9) to determine the growth and photosynthesis recovery level, which was not confirmed by visual judgment. The kinetic curve patterns of CF in three different drought stressed seedling groups were found to be different for the early detection of drought stress. All the 16 CF parameters decreased continuously with exposure to drought stress and drastically decreased from D5 (32.1%) where the visual judgment was possible. The fluorescence decline ratio (Rfd_Lss) started to decrease from the initial drought stress level (D5 - D6), and the Maximum PSII quantum yield (Fv/Fm) was significantly decreased in the later extreme drought stress range (D7 - D9) by re-irrigation recovery test. Thus, Rfd_Lss and Fv/Fm parameters were finally selected as potent indicators of growth and photosynthesis recovery in the initial and later stages of drought stress. Also, to the differences in the numerical values of the individual chlorophyll fluorescence parameters, the drought stress level was intuitively confirmed through the image. These results indicate that Rfd and Fv/Fm can be considered as potential CF parameters for the detection of low and extremely high drought stress, respectively. Furthermore, Fv/Fm can be considered as the best CF parameters for recovery at re-irrigation.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.93-105
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• 2018

Precise investigation and interpretation of the ground subsidence risk factors needed to predict and evaluate the settlement problems of the surrounding ground due to the ground excavation. There are various geophysical exploration methods to investigate the ground subsidence risk factors. However, there are factors that influence the characteristics of the underground medium in these geophysical methods, and the actual soil contains complex factors affecting geophysical exploration. Therefore, it is necessary to analyze the effects on the geophysical methods based on the understanding of the geotechnical properties of soil. In this study, a test bed was constructed to consider various complicated factors in the complex ground and the ground behavior was analyzed by numerical analysis. In addition, we analyzed the limitations on investigating the ground subsidence risk factors through ground penetration radar (GPR) survey. As a result, ground subsidence of Open-cut Type Excavation is caused by various factors. Especially, in the case of soft ground condition, it was found that it was greatly influenced by the flow change of groundwater level. At the center frequency of GPR of 250 MHz, the attenuation of the electromagnetic wave is severely attenuated in the clay with high electrical conductivity, making it difficult to penetrate deeply into the ground (4 m below the surface). As the electromagnetic waves pass through the groundwater level below the groundwater, the attenuation of the electromagnetic waves becomes severe.

• Journal of the Korean Geophysical Society
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• v.5 no.3
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• pp.199-209
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• 2002

We have carried out a nondestructive close examination for the purpose of the structural safety diagnosis of the Dabo Pagoda of Bulkuk temple located in Kyungju, Kyungbuk Korea. For estimating the mechanical properties of each rock block of the pagoda, ultrasonic measurements were conducted at 641 points of 255 blocks. The P-wave velocity ranges from 584m/sec through 5,169m/sec, and averages 2,901m/sec Based on this result, the uniaxial compressive strength was estimated to be $93{\sim}1,943kg/cm^2\;with\;396kg/cm^2$ of average, and the index of weathering is $0.07{\sim}0.88$ with 0.43 of average, which means the moderate degree of weathering. The comparison of the rock strength of each block with the overburden acting on the block reveals that the rock blocks related to the structure of the pagoda are relatively sound for uniform stress, but it is highly possible for a concentrated stress to lead to a partial failure. We suggest a monitoring of cracks due to the concentrated stress. The parapets of 1st and 2nd floors composed of small rock pieces are severely weathered. However, this is not directly related to the structural safety of the pagoda.