• Journal of the Korean Geotechnical Society
• /
• v.40 no.3
• /
• pp.77-84
• /
• 2024

Aging and damaged underground utilities cause cavity and ground subsidence under roads, which can cause economic losses and risk user safety. This study used infrared cameras to assess the thermal characteristics of such cavities and evaluate their reliability using a CNN algorithm. PVC pipes were embedded at various depths in a test site measuring 400 cm × 50 cm × 40 cm. Concrete blocks were used to simulate road surfaces, and measurements were taken from 4 PM to noon the following day. The initial temperatures measured by the infrared camera were 43.7℃, 43.8℃, and 41.9℃, reflecting atmospheric temperature changes during the measurement period. The RP algorithm generates images in four resolutions, i.e., 10,000 × 10,000, 2,000 × 2,000, 1,000 × 1,000, and 100 × 100 pixels. The accuracy of the CNN model using RP images as input was 99%, 97%, 98%, and 96%, respectively. These results represent a considerable improvement over the 73% accuracy obtained using time-series images, with an improvement greater than 20% when using the RP algorithm-based inputs.

• Analytical Science and Technology
• /
• v.37 no.3
• /
• pp.143-154
• /
• 2024

In this study, we improved the vitamin C test method and reviewed data on the adjustable range of chromatography conditions for quantification. First, we adjusted the mobile phase conditions such as solvent composition, salt concentration, pH and column temperature and in particular, it was confirmed through an improved test method that the peak derived from the buffer solution could be clearly separated from the target component, vitamin C by adjusting the pH. The retention time of vitamin C was partially changed by adjusting the column diameter, length and particle size but the number of theoretical plates indicated similar values and did not affect the separation and quantitative analysis of the target component. The flow rate according to the column specifications was derived from the equation proposed by the U.S. FDA (Food and Drug administration) and the Korean MFDS (Ministry of Food and Drug Safety), and evaluation of the applicability to vitamin complexes showed high selectivity for vitamin C even with altered stationary phase conditions and flow rates. In conclusion, vitamin C can be optimally separated and detected by changing the chromatographic method conditions and it was confirmed that the mobile and stationary phase conditions of liquid chromatography can be slightly adjusted in case the assay method uses an isocratic elution.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.26 no.1
• /
• pp.53-62
• /
• 2024

In this study, we built a model to estimate frost occurrence in South Korea using single-input deep learning and multi-input deep learning. Meteorological factors used as learning data included minimum temperature, wind speed, relative humidity, cloud cover, and precipitation. As a result of statistical analysis for each factor on days when frost occurred and days when frost did not occur, significant differences were found. When evaluating the frost occurrence models based on single-input deep learning and multi-input deep learning model, the model using both GRU and MLP was highest accuracy at 0.8774 on average. As a result, it was found that frost occurrence model adopting multi-input deep learning improved performance more than using MLP, LSTM, GRU respectively.

• Journal of Korean Neurosurgical Society
• /
• v.67 no.4
• /
• pp.451-457
• /
• 2024

Objective : Exploring protein requirements for critically ill patients has become prominent. On the other hand, considering the significant impact of coma therapy and targeted temperature management (TTM) on the brain as well as systemic metabolisms, protein requirements may plausibly be changed by treatment application. However, there is currently no research on protein requirements following the application of these treatments. Therefore, the aim of this study is to elucidate changes in patients' protein requirements during the application of TTM and coma therapy. Methods : This study is a retrospective analysis of prospectively collected data from March 2019 to May 2022. Among the patients admitted to the intensive care unit, those receiving coma therapy and TTM were included. The patient's treatment period was divided into two phases (phase 1, application and maintenance of coma therapy and TTM; phase 2, tapering and cessation of treatment). In assessing protein requirements, the urine urea nitrogen (UUN) method was employed to estimate the nitrogen balance, offering insight into protein utilization within the body. The patient's protein requirement for each phase was defined as the amount of protein required to achieve a nitrogen balance within ±5, based on the 24-hour collection of UUN. Changes in protein requirements between phases were analyzed. Results : Out of 195 patients, 107 patients with a total of 214 UUN values were included. The mean protein requirement for the entire treatment period was 1.84±0.62 g/kg/day, which is higher than the generally recommended protein supply of 1.2 g/kg/day. As the treatment was tapered, there was a statistically significant increase in the protein requirement from 1.49±0.42 to 2.18±0.60 in phase 2 (p<0.001). Conclusion : Our study revealed a total average protein requirement of 1.84±0.62 g during the treatment period, which falls within the upper range of the preexisting guidelines. Nevertheless, a notable deviation emerged when analyzing the treatment application period separately. Hence, it is recommended to incorporate considerations for the type and timing of treatment, extending beyond the current guideline, which solely accounts for the severity by disease.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.52 no.3
• /
• pp.18-32
• /
• 2024

This study aims to analyze the summer human thermal environment in Jeju City's outdoor parking lots by measuring microclimate data and comparing pavement and vegetation albedoes and elements through computer simulations. In measured cases, results due to albedo showed no significance, but there was a significant difference between sunny and shaded areas by trees. The sunny area had a PET (physiological equivalent temperature) in the 'very hot' level, while the shaded area exhibited a 2-step lower 'warm' level. UTCI (universal thermal climate index) also showed that the sunny area was in the 'very strong heat stress' level, whereas the shaded area was 1-step lower in the 'strong heat stress' level, confirming the role of trees in reducing incoming solar radiant energy. Simulation results, using the measured albedoes, closely resembled the measured results. Regarding vegetation, scenarios with a wide canopy, high leaf density, and narrow planting spacing were effective in mitigating the human thermal environment, and the differences due to tree height varied across scenarios. The scenario with the lowest PET value was H9W9L3D8 (tree height 9m, canopy width 9m, leaf area index 3.0, planting spacing 8m), indicating a 0.7-step decrease compared to the current landscaping scenario. Thus, it was confirmed that, among landscaping elements, trees have a significant impact on the summer human thermal environment compared to ground pavement.

• Advances in aircraft and spacecraft science
• /
• v.11 no.1
• /
• pp.83-103
• /
• 2024

Adhesive bonding is currently widely used in many industrial fields, particularly in the aeronautics sector. Despite its advantages over mechanical joints such as riveting and welding, adhesive bonding is mostly used for secondary structures due to its low peel strength; especially if it is simultaneously exposed to temperature and humidity; and often presence of bonding defects. In fact, during joint preparation, several types of defects can be introduced into the adhesive layer such as air bubbles, cavities, or cracks, which induce stress concentrations potentially leading to premature failure. Indeed, the presence of defects in the adhesive joint has a significant effect on adhesive stresses, which emphasizes the need for a good surface treatment. The research in this field is aimed at minimizing the stresses in the adhesive joint at its free edges by geometric modifications of the ovelapping part and/or by changing the nature of the substrates. In this study, the finite element method is used to describe the mechanical behavior of bonded joints. Thus, a three-dimensional model is made to analyze the effect of defects in the adhesive joint at areas of high stress concentrations. The analysis consists of estimating the different stresses in an adhesive joint between two 2024-T3 aluminum plates. Two types of single lap joints(SLJ) were analyzed: a standard SLJ and another modified by removing 0.2 mm of material from the thickness of one plate along the overlap length, taking into account several factors such as the applied load, shape, size and position of the defect. The obtained results clearly show that the presence of a bonding defect significantly affects stresses in the adhesive joint, which become important if the joint is subjected to a higher applied load. On the other hand, the geometric modification made to the plate considerably reduces the various stresses in the adhesive joint even in the presence of a bonding defect.

• Korean Journal of Environmental Biology
• /
• v.41 no.4
• /
• pp.720-734
• /
• 2023

To understand the spatiotemporal distribution pattern of zooplankton and the environmental factors influencing zooplankton abundance in Gomso Bay, major harvesting area of Manila clam (Venerupis philippinarum) in South Korea, zooplankton sampling was conducted four times in autumn (October 2022), winter (January 2023), early spring (March 2023), and spring (May 2023). Among the environmental factors of Gomso Bay, water temperature, chlorophyll a concentration (Chl-a), dissolved oxygen (DO), and pH observed different patterns, while salinity and suspended particulate matter(SPM) showed no significant statistical differences between the survey periods. The zooplankton in Gomso Bay occurred 33, 29, 27, and 29 taxonomic groups during each respective survey period. In October 2022 and May 2023, arthropod plankton were dominated, while in January and March 2023, protozoa were primarily dominant. Among the Arthropods, copepods including Acartia hongi, Paracalanus parvus s. l., Corycaeus spp., and Oithona spp. commonly found along Korean coastal areas of the Yellow Sea, were dominated. Cluster analysis based on zooplankton abundance indicated a single community (stable condition) in each season, attributed to low dissimilarity distances, while three distinct clusters (autumn, winter-early spring, spring) between seasons indicated a highly seasonal environment in Gomso Bay.

• Korean Journal of Ecology and Environment
• /
• v.57 no.3
• /
• pp.162-168
• /
• 2024

The purpose of this study was to record for the first time in Korea the presence of Melanoides tuberculata (an invasive alien species), which was confirmed during the "National Survey on the Status of Alien Species" in Jukdang stream (also known as Guppy Stream, located in Icheon, Gyeonggi Province), which is affected by the year-round discharge of heated effluent from a large semiconductor factory and where various tropical organisms, including ornamental fish, appear due to artificial release. A Total of 52 specimens were collected, and they can be visually distinguished from native melanian snails by their reddish-brown flames and spots. Genetic analysis further confirmed the species as Melanoides tuberculate. Melanoides tuberculata typically inhabits tropical climates, but its presence has been confirmed in altered aquatic environments such as Jukdang stream, where the water temperature remains warm even in a temperate climate. This indicates the need for further monitoring of domestic streams with similar conditions, particularly those receiving heated effluent, like Jukdang stream. Additionally, due to its strong reproductive capacity, including parthenogenesis, and its adaptability to various environments, there have been cases where the populations of Pomacea lineata and Aylacostoma tenuilabris have declined. This suggests that Melanoides tuberculata may have a competitive advantage in interspecific competition, potentially suppressing native species populations if it spreads within the domestic ecosystem. Melanoides tuberculata serves as an intermediate host for parasites that can cause diseases in both humans and animals, raising public health concerns in many countries. There is also a significant risk that it could be mistaken for native melanian snail species and consumed, which necessitates a high level of caution.

• Journal of Bio-Environment Control
• /
• v.32 no.4
• /
• pp.328-335
• /
• 2023

For appropriate nutrient management and enhanced plant growth, soil sensors which reflect soil nutrient levels are required. Because there is no available sensor for nutrient monitoring, electrical conductivity (EC) sensor can be used to evaluate soil nutrient levels. Soil nutrient management using EC sensors would be possible by understanding the relationship between sensor EC values and soil temperature, moisture, and nutrient content. However, the relationship between soil sensor EC values and plant available nutrients was not investigated. Therefore, the objectives of the study were to evaluate effect of different amount of urea on soil EC monitored by sensors during pepper and broccoli cultivation and to predict the plant available nutrient contents in soil. During the cultivation period, soil was collected periodically for analyzing pH and EC, and the available nutrient contents. The sensor EC value increased as the moisture content increased, and low fertilizer treated soil showed the lowest EC value. Principal component analysis was performed to determine the relationship between sensor EC and available nutrients in soil. Sensor EC showed a strong positive correlation with nitrate nitrogen and available Ca. In addition, sum of available nutrients such as Ca, Mg, K, P, S and N was positively related to the sensor EC values. Therefore, EC sensors in open field can be used to predict plant available nutrient levels for proper management of the soil.

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