• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.21-27
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• 2024

In this study, the corrosion density of tendon was evaluated with changing chloride and hydroxide ions. To simulate an accelerated corrosive environment, wet sand was used instead of concrete, and the tests were conducted considering three levels of chloride concentration (0.0, 0.125, and 0.250mol/l ) and three [Cl^-]/[OH^-] ratios (0.3, 0.6, and 0.9). The corrosion density was measured to 5.13 µA/cm² at 0.0mol/l and increased with the chloride concentration. Additionally, no significant differences were observed over 0.125mol/l of chloride concentration. When [OH^-] increased with a given chloride concentration (0.125mol/l), the corrosion density decreased linearly, showing effective control of corrosion density even at high chloride concentrations. Notably, the measured corrosion amounts were lower than those under of 0.0mol/l condition. Furthermore corrosion density and influencing parameters were normalized with the maximum and minimum results, and the relation between them was analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.55-61
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• 2024

Recently, the number of aging concrete structures is steadily increasing. This is because many of these structures are reaching their expected lifespan. Such structures require accurate inspections and persistent maintenance. Otherwise, their original functions and performance may degrade, potentially leading to safety accidents. Therefore, research on objective inspection technologies using deep learning and computer vision is actively being conducted. High-resolution images can accurately observe not only micro cracks but also spalling and exposed rebar, and deep learning enables automated detection. High detection performance in deep learning is only guaranteed with diverse and numerous training datasets. However, surface damage to concrete is not commonly captured in images, resulting in a lack of training data. To overcome this limitation, this study proposed a method for generating concrete surface damage images, including cracks, spalling, and exposed rebar, using stable diffusion. This method synthesizes new damage images by paired text and image data. For this purpose, a training dataset of 678 images was secured, and fine-tuning was performed through low-rank adaptation. The quality of the generated images was compared according to three base models of stable diffusion. As a result, a method to synthesize the most diverse and high-quality concrete damage images was developed. This research is expected to address the issue of data scarcity and contribute to improving the accuracy of deep learning-based damage detection algorithms in the future.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.3-14
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• 2024

Unlike conventional construction production methods, OSC (Off-Site Construction) have many restrictions depending on the production environment and technology, so it is important to develop a design plan considering these restrictions and select the optimal design alternative considering the overall efficiency of the building production process. Accordingly, the construction industry is paying attention to DfMA (Design for Manufacturing & Assembly) to derive the optimal design plan for the OSC project. Leading OSC countries such as Singapore and the United Kingdom have recognized the need to apply DfMA and presented DfMA guidelines and application strategies suitable for the characteristics of the OSC industry, and several researchers are conducting research to integrate DfMA into the construction industry. However, in the case of Korea, the need for industrial application and industrial application of DfMA is recognized, but there are no methods and tools necessary to implement the concept of DfMA in the design of actual construction projects. Therefore, this study aims to present the basic direction of strategy for applying DfMA and developing tools for the development of the domestic OSC industry by analyzing the development and application of DfMA in overseas construction. The results of this study can be used as basic data for the development of DfMA tools suitable for the domestic OSC industry and the establishment of policies related to DfMA in the future.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.200-208
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• 2024

Chung's equations-IX and Chung's equation-XII were utilized to predict the fire risk and evaluate fire risk ratings for four types of wood: camphor, cherry, rubber, and elm trees. The combustion tests were conducted using a cone calorimeter test method by ISO 5660-1 standards. The fire risk and fire risk rating (FRR) were compared for Fire Risk Index-IX (FRI-IX) and Fire Risk Index-XII (FRI-XII). The results yielded Fire Performance Index-XI (FPI-XI) ranging from 0.08 to 11.48 and Fire Growth Index-XI (FGI-XI) ranging from 0.67 to 111.89. The Fire Risk Index-XII (FRI-XII), indicating fire risk rating, exhibited an increasing order of cherry (0.45): Grade A (Ranking 5) < PMMA (1): Grade A (Ranking 4) < elm (1.23): Grade A (Ranking 3) < rubber (1.56): Grade A (Ranking 2) << camphor (148.23): Grade G (Ranking 1). Additionally, the fire risk index-IX (FRI-IX) was cherry (0): Grade A (Ranking 3) ≈ rubber (0): Grade A (Ranking 3) ≈ elm tree (0): Grade A (Ranking 3) < PMMA (1): Grade A (Ranking 2) << camphor tree (66.67): Grade G (Ranking 1). In general, camphor was found to have the highest fire risk. In conclusion, although the expression of the index is different as shown based on the standards of FRI-IX and FRI-XII, predictions based on fire risk assessment of combustible materials showed similar trends.

• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.3
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• pp.209-218
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• 2024

The National Institute of Agricultural Sciences (NAS) operates in-house long-range climate forecasting system to support the agricultural use of climate forecast data. This system, developed through collaborative research with Pusan National University, is based on the PNU/RDA Coupled General Circulation Model (CGCM) and includes the regional climate model WRF (Weather Research and Forecasting). It generates detailed climate forecast data for periods ranging from 1 to 6 months, covering 20 key variables such as daily maximum, minimum, and average temperatures, precipitation, and agricultural meteorological elements like solar radiation, soil moisture, and ground temperature-factors essential for agricultural forecasting. The data are provided at a daily temporal resolution with a spatial resolution of a 5km grid, which can be used in point form (interpolated) or averaged across administrative regions. The system's seasonal temperature and precipitation forecasts align closely with observed climatological data, accurately reflecting spatial and topographical influences, confirming its reliability. These long-range forecasts from NAS are expected to offer valuable insights for agricultural planning and decision-making. The detailed forecast data can be accessed through the Climate Change Assessment Division of NAS.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.3
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• pp.50-59
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• 2010

A pilot-scale test for production of biogas was conducted in an specially designed anaerobic digester (KH-ABC) in which the highly concentrated organic waste (food-waste and piggery-manure) was treated. The effect of inhibitive material to the reaction on anaerobic digestion and the feasibility of digested fluid for the liquefied fertilizer were investigated. The production rate of biogas, the concentration of methane($CH_4$) in biogas, and the digesting rate of volatile solid(VS) were analyzed in the variance of the operating conditions ; the influent rate, the mixture ratio of food waste and piggery manure, and the hydraulic retention time(HRT), etc. The production rate of biogas increased from 1.2 to $2.0kg-VS/m^3{\cdot}d$ with the organic loading rate(OLR). The most suitable operating conditions were recorded at $6m^3/day$ of an influent rate, 2:3 of the raw material mixture ratio(food waste : piggery manure) and 25 days of HRT, respectively. Under those conditions, the production rate of biogas, the concentration of methane($CH_4$) in biogas and the digesting rate of volatile solid(VS) were $220m^3/day$, 64%, and 70%, respectively. The concentration of inhibitive materials was below toxic standard and the anaerobic digested fluid(raw material mixture ratio of 3:7) could meet the condition of the liquefied fertilizer.

• Journal of Korea Water Resources Association
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• v.57 no.9
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• pp.571-583
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• 2024

Forecasting dam inflows in the medium to long term is crucial for effective dam operation and the prevention of water-related disasters such as floods and droughts. However, the increasing frequency of extreme weather events due to climate change has made hydrological forecasting more challenging. Since 2000, seasonal weather forecasts, which provide predictions for weather variables up to about seven months ahead, and their hydrological interpretation, known as Seasonal Flow Forecasts (SFFs) have gained significant global interest. This study utilises seasonal weather forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF), converting them into inflow forecasts using a hydrological model for 12 multipurpose dams in South Korea from 2011 to 2020. We then compare the performance of these SFFs with the Ensemble Streamflow Prediction (ESP). Our results indicate that while SFFs are more effective for short-term predictions of 1-2 months, ESP outperforms SFFs for long-term predictions. Seasonally, the performance of SFFs is higher in October-November but lower from December to February. Moreover, our findings demonstrate that SFFs are highly effective in quantitatively predicting dry conditions, although they tend to underestimate inflows under wet conditions.

• Journal of the Society of Disaster Information
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• v.20 no.3
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• pp.563-572
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• 2024

Purpose: This study aims to assess the physical cognition according to changes in the weight of firefighting Self Contained Breathing Apparatus (SCBA), and to provide foundational data for establishing standards for firefighting SCBA based on these results. Method: The study investigated and analyzed changes in physical changes, Rating of Perceived Exertion (RPE), and cognitive factors among firefighters and non-firefighters wearing three different types of SCBA with varying weights, following appropriate exercise loads. Result: In the case of the firefighter group, wearing SCBA with varying weights during exercise did not show significant differences in respiratory rate, heart rate, and blood pressure. Similarly, in the non-firefighter group, differences in weight change were not significant. Additionally, both groups did not demonstrate differences in RPE based on SCBA weight changes, and participants did not cognize changes in SCBA weight during the experiment. Conclusion: Due to the low level of physical cognition based on changes in SCBA weight, it is inferred that even if the current firefighting SCBA weight is additionally increased to 4kg, firefighters' cognitive fatigue levels would remain similar to or not significantly higher than current levels

• International Journal of Advanced Culture Technology
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• v.12 no.3
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• pp.29-36
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• 2024

The public can now access movies faster and more easily thanks to over-the-top (OTT) services. The audience may be impacted by period dramas, where accurate costume reproduction is crucial. For filmmakers, it is critical to replicate period costumes using precise historical information. The goal of this study is to act as a reference so that, when it comes to period dramas, viewers can evaluate them using impartial criteria and movie producers can use data based on fact to plan their costumes. The film Napoleon won the British Academy Award for Costume after hiring costume experts to create 95% of the entire costume, according to data from the Napoleon I Museum. Following the French Revolution, the ostentatious and ornate men's attire vanished, to be replaced by a more modest and functional outfit. For tops, vests were cut to waist length, shirts, cravats, and carrick were worn, and tailcoats were the norm. The pants were swapped out for loose-fitting ones. The glitzy hues and embellishments from the bygone era progressively vanished and formed the foundation of the contemporary men's costume, which is dominated by black. The hats worn were tricorn, bicorn, top hat, and bowler, and the hairstyle changed from long to short gradually. The civil class wore short tops called carmagnoles. Napoleon wore a high-collared Napoleon collar and a tailcoat with a bicorn, which became his emblem. Green, navy, and white were the colors of the uniform, and a gray woolen coat was worn outside. The elaborately decorated costumes were worn to court and to banquets; the Napoleonic coronation costume was embellished with gold embroidery on silk, red velvet, and martyred hair; the post-revolutionary costumes gradually became more colorful. In the movie Napoleon, period clothing items were well represented, with the aristocracies wearing dark tailcoats, vests, shirts, and cravats. Based on the data from the men's costume, Napoleon's outfit in the movie was made more similarly. This study's limitation is that not every character in the movie could have their costume examined, and the material matter could not be precisely determined by examining the images displayed on the screen. Given that portraits typically feature a great deal of noble imagery, the clothing worn by common people is also associated with data limitations when it comes to movie costume design.

• Computers and Concrete
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• v.34 no.3
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• pp.329-346
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• 2024

In this study, it is aimed to investigate the vertical seismic performance of reinforced concrete (R/C) frame buildings in two different building stocks, one of which consists of those designed as per the previous Turkish Seismic Code (TSC-2007) that does not consider the vertical earthquake load, and the other of which consists of those designed as per the new Turkish Seismic Code (TSCB-2018) that considers the vertical earthquake load. For this aim, three R/C buildings with heights of 15 m, 24 m and 33 m are designed separately as per TSC-2007 and TSCB-2018 based on some limitations in terms of seismic zone, soil class and structural behavior factor (Rx/Ry) etc. The vertical earthquake motion effects are identified according to the linear time-history analyses (LTHA) that are performed separately for only horizontal (H) and combined horizontal+vertical (H+V) earthquake motions. LTHA is performed to predict how vertical earthquake motion affects the response of the designed buildings by comparing the linear response parameters of the base shear force, the base overturning, the base axial force, top-story vertical displacement. Nonlinear time-history analysis (NLTHA) is generally required for energy dissipative buildings, not required for design of buildings. In this study, the earthquake records are scaled to force the buildings in the linear range. Since nonlinear behavior is not expected from the buildings herein, the nonlinear time-history analysis (NLTHA) is not considered. Eleven earthquake acceleration records are considered by scaling them to the design spectrum given in TSCB-2018. The base shear force is obtained not to be affected from the combined H+V earthquake load for the buildings. The base overturning moment outcomes underline that the rigidity of the frame system in terms of the dimensions of the columns can be a critical parameter for the influence of the vertical earthquake motion on the buildings. In addition, the building stock from TSC-2007 is estimated to show better vertical earthquake performance than that of TSCB-2018. The vertical earthquake motion is found out to be highly effective on the base axial force of 33 m building rather than 15 m and 24 m buildings. Thus, the building height is a particularly important parameter for the base axial force. The percentage changes in the top-story vertical displacement of the buildings designed for both codes show an increase parallel to that in the base axial force results. To extrapolate more general results, it is clear to state that many buildings should be analyzed.