• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.981-992
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• 2023

Due to recent global climate change, the scale of flood damage is increasing as rainfall is concentrated and its intensity increases. Rain on a scale that has not been observed in the past may fall, and long-term rainy seasons that have not been recorded may occur. These damages are also concentrated in ASEAN countries, and many people in ASEAN countries are affected, along with frequent occurrences of flooding due to typhoons and torrential rains. In particular, the Bandung region which is located in the Upper Chitarum River basin in Indonesia has topographical characteristics in the form of a basin, making it very vulnerable to flooding. Accordingly, through the Official Development Assistance (ODA), a flood forecasting and warning system was established for the Upper Citarium River basin in 2017 and is currently in operation. Nevertheless, the Upper Citarium River basin is still exposed to the risk of human and property damage in the event of a flood, so efforts to reduce damage through fast and accurate flood forecasting are continuously needed. Therefore, in this study an artificial intelligence-based river flood water level forecasting model for Dayeu Kolot as a target station was developed by using 10-minute hydrological data from 4 rainfall stations and 1 water level station. Using 10-minute hydrological observation data from 6 stations from January 2017 to January 2021, learning, verification, and testing were performed for lead time such as 0.5, 1, 2, 3, 4, 5 and 6 hour and LSTM was applied as an artificial intelligence algorithm. As a result of the study, good results were shown in model fit and error for all lead times, and as a result of reviewing the prediction accuracy according to the learning dataset conditions, it is expected to be used to build an efficient artificial intelligence-based model as it secures prediction accuracy similar to that of using all observation stations even when there are few reference stations.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.3
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• pp.135-145
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• 2022

Due to COVID 19, we are facing unprecedented phenomena. Among various industries, the aviation industry, as it is directly affected by the corona crisis is actively establishing various survival strategies, such as expanding cargo transportation. The market size of air cargo transportation is continuously increasing due to the characteristics that distinguish it from other transportation, and as individualism and selfishness deepen in the aftermath of COVID 19, it can be inferred that the concept of reciprocity within distribution channels will become important in the post-corona era. The specific contents of this study(research question) are as follows. First, as a central member of the air logistics distribution channel, logistics service companies business process and the sub-dimensions of trust of are identified, and how trust is built with transportation companies is investigated. Second, the effect of such trust on the various performances of logistics service companies is analyzed. Third, we examine whether the influences of the sub-dimensions of trust change according to the perceived reciprocity of logistics service companies. In addition, we investigate whether the perceived reciprocity changed before and after the corona situation. In particular, this study theoretically integrates the concepts of trust and commitment, which have been distinguished in many prior studies, to improve the parsimony and practicality of the research model. This study will be able to present useful academic and practical implications by empirically examining how trust is built between members of the air logistics distribution channel and furthermore, how much it affects the performance of logistics service companies, and by identifying the moderating effect of reciprocity.

• Clean Technology
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• v.30 no.2
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• pp.134-144
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• 2024

In this study, the mechanical stability of red mud was improved for its commercial use as a catalyst to effectively decompose HFC-134a, one of the seven major greenhouse gases. Red mud is an industrial waste discharged from aluminum production, but it can be used for the decomposition of HFC-134a. Red mud can be manufactured into a catalyst via the crushing-preparative-compression molding-firing process, and it is possible to improve the catalyst performance and secure mechanical stability through calcination. In order to determine the optimal heat treatment conditions, pellet-shaped compressed red mud samples were calcined at 300, 600, 800 ℃ using a muffle furnace for 5 hours. The mechanical stability was confirmed by the weight loss rate before and after ultra-sonication after the catalyst was immersed in distilled water. The catalyst calcined at 800 ℃ (RM 800) was found to have the best mechanical stability as well as the most catalytic activity. The catalyst performance and durability tests that were performed for 100 hours using the RM 800 catalyst showed thatmore than 99% of 1 mol% HFC-134a was degraded at 650 ℃, and no degradation in catalytic activity was observed. XRD analysis showed tri-calcium aluminate and gehlenite crystalline phases, which enhance mechanical strength and catalytic activity due to the interaction of Ca, Si, and Al after heat treatment at 800 ℃. SEM/EDS analysis of the durability tested catalysts showed no losses in active substances or shape changes due to HFC-134a abasement. Through this research, it is expected that red mud can be commercialized as a catalyst for waste refrigerant treatment due to its high economic feasibility, high decomposition efficiency and mechanical stability.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.153-161
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• 2023

The worldwide effects of COVID-19 have led to a surge in online shopping and contactless services. The consumption pattern has caused the issues such as the environmental pollution together with the increase of plastic waste. Reducing the reliance on the petroleum based plastic use for the package and replacing it with environmentally friendly material are the simple ways in order to solve those problems. Paper is an eco-friendly product with high recyclability as the food packaging materials but has still poor barrier properties. A barrier coating on surface of the paper can be achieved with the proper packaging materials featuring water, gas and grease barrier. Polyethylene (PE) or polypropylene (PP) coatings which are generally laminated or coated to paper are widely used in food packaging applications to protect products from moisture and provide water or grease resistance. However, recycling of packaging containing PE or PP matrix is limited and costly because those films are difficult to degrade in the environment. This study investigated the recyclability of modified acrylic emulsion coating papers compared to PE and PP polymer matrixes as well as their mechanical and gas barrier properties. The results showed that PE or modified acrylic emulsion coated papers had better mechanical properties compared to the uncoated paper as a control. PE or PP coating papers showed strong oil resistance property, achieving a kit rating of 12. Those papers also had a significantly higher percentage of screen reject during the recycling process than modified acrylic coated paper which had a screen rejection rate of 6.25%. In addition an uncoated paper had similar value of a screen rejection rate. It may suggest that modified acrylic emulsion coating paper can be more easily recycled than PE or PP coating papers. The overall results of the study found that modified acrylic emulsion coating paper would be a viable alternative to suggest a possible solution to an environmental problem as well as enhancing the weak mechanical and poor gas barrier properties of the paper against moisture.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.13-28
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• 2023

This study assessed the biochemical methane potential (B_u-P) of three grass species-Poa pratensis (PP), Zoysia japonica (ZJ), and Agrostis stolonifera (AS). B_u-P values were determined as 0.330 Nm³/kg-VS_added for PP, 0.297 Nm³/kg-VS_added for ZJ, and 0.261 Nm³/kg-VS_added for AS. Notably, PP exhibited superior suitability for methane production. The investigation also examined the impact of silage storage duration on PP grass clippings, revealing a 19% decline in B_u-P from an initial value of 0.269 Nm³/kg-VS_added on day 0 to 0.217 Nm³/kg-VS_added on day 180. Throughout the storage period, there were significant increases in neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) contents, rising from 67.59%, 39.68%, and 3.02% on day 0 to 77.12%, 54.65%, and 6.24% on day 180, respectively. These findings highlight the influence of storage duration on the anaerobic digestibility of PP grass clippings. To effectively utilize grass clippings as a renewable resource for methane production, further studies considering factors such as initial moisture content, pretreatment methods, and potential effects of residual pesticides are necessary to optimize anaerobic digestion efficiency for herbaceous biomass.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.229-241
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• 2024

With the advancement of big data processing technology using cloud platforms, access, processing, and analysis of large-volume data such as satellite imagery have recently been significantly improved. In this study, the Change Detection Method, a relatively simple technique for retrieving soil moisture, was applied to the backscattering coefficient values of pre-processed Sentinel-1 synthetic aperture radar (SAR) satellite imagery product based on Google Earth Engine (GEE), one of those platforms, to estimate the surface soil moisture for six observatories within the Yongdam Dam watershed in South Korea for the period of 2015 to 2023, as well as the watershed average. Subsequently, a correlation analysis was conducted between the estimated values and actual measurements, along with an examination of the applicability of GEE. The results revealed that the surface soil moisture estimated for small areas within the soil moisture observatories of the watershed exhibited low correlations ranging from 0.1 to 0.3 for both VH and VV polarizations, likely due to the inherent measurement accuracy of the SAR satellite imagery and variations in data characteristics. However, the surface soil moisture average, which was derived by extracting the average SAR backscattering coefficient values for the entire watershed area and applying moving averages to mitigate data uncertainties and variability, exhibited significantly improved results at the level of 0.5. The results obtained from estimating soil moisture using GEE demonstrate its utility despite limitations in directly conducting desired analyses due to preprocessed SAR data. However, the efficient processing of extensive satellite imagery data allows for the estimation and evaluation of soil moisture over broad ranges, such as long-term watershed averages. This highlights the effectiveness of GEE in handling vast satellite imagery datasets to assess soil moisture. Based on this, it is anticipated that GEE can be effectively utilized to assess long-term variations of soil moisture average in major dam watersheds, in conjunction with soil moisture observation data from various locations across the country in the future.

• Journal of Navigation and Port Research
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• v.48 no.3
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• pp.232-238
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• 2024

This study examines the effectiveness of Gamcheon Port's leading lights in reflecting the characteristics of ship traffic entering the port. The leading light of Gamcheon Port was proposed and installed in 1996 during the basic design process of supplementing the port's route signs for the entry and exit of 4,000 TEU container ships. Since then, it has been improved to accommodate the entry of 50,000 DWT general cargo ships and to reflect the crane height of Hanjin Pier, as a result of a review study conducted by the Busan Regional Maritime Affairs and Fisheries Administration to improve the still temperature of Gamcheon Port by relocating existing outer facilities. However, an analysis of the current characteristics of maritime traffic at Gamcheon Port reveals that maritime traffic congestion is smooth and the proportion of small and medium-sized ships under 10,000 tons is higher than that of large ships, resulting in decreased efficiency of the leading lights to respond to the entry of large ships. Nevertheless, considering the increasing CAGR of the entry ratio of ships of 30,000 tons or more by 8.45%, preparations for the anticipated increase in the proportion of large ships entering the port in the future are necessary, and it is preferable to maintain the function of the leading lights rather than demolishing the entrance to Gamcheon Port. The narrow nature of the Gamcheon Port route poses a higher risk of collision when ships entering and exiting encounter each other, which can burden the navigator. Therefore, instead of maintaining the function of the leading lights, it is possible to relocate the conduction light to reduce maintenance burden and install a direction light in its place. When installing the direction light, it is worth considering using Double Sector Lights instead of the currently installed Single Sector Lights at nearby Busan Bukhang Port, as the former can improve user satisfaction by providing a clearer middle line and reducing difficulties in distinguishing between points.

• Food Science and Preservation
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• v.30 no.1
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• pp.78-87
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• 2023

This study was conducted to evaluate the effect of different 1-methylcyclopropene (1-MCP) concentrations on fruit quality of small-sized RubyS apples during cold storage. After harvesting, the fruits were treated with 1-MCP at 0.5 or 1 µL/L concentrations and, subsequently, stored at 0℃ for 6 months. After 6 months, the flesh firmness of untreated fruits, which was 85.4 N at harvest, had gradually decreased to 46.5 N; however, that of 1-MCP-treated fruits was maintained at 59.1 and 59.5 N. Titratable acidity (TA) of untreated fruits had also decreased from 0.42 to 0.24%, whereas that of 1-MCP-treated fruits was maintained at 0.26 and 0.27%. Soluble solids content (SSC) did not differ in all fruits. However, the 1-MCP-treated fruits had lower levels of SSC/TA ratio than untreated fruits. Moreover, after 6 months, the ethylene production had increased to 47.0 µL/kg/h in the untreated fruits, whereas 1-MCP blocked the ethylene production at 1.4 and 1.7 µL/kg/h. The weight loss and peel color variables remained unaffected by 1-MCP treatments. Thus, these results indicated that, for RubyS apples, the storability was only 2 months at 0℃ without treatment, which can be extended to 6 months with 1-MCP treatments. The application of 1-MCP at 0.5 µL/L concentration is effectively and economically sufficient to maintain the quality of RubyS apples.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.97-106
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• 2024

This study utilized the non-invasive MyotonPRO^® device to analyze the stiffness in breast muscles of commercial broilers (Ross 308 and Arbor Acres) and compared these findings with data reported for Ross 708, where Woody Breast (WB) symptoms had been previously documented. The research revealed that Ross 308 and Arbor Acres displayed relatively lower stiffness values compared to Ross 708, suggesting a lack of WB expression. These results indicate differentiation in breast muscle traits across strains and underscore the necessity for further research into factors influencing WB manifestation. The study also measured additional muscle tone characteristics such as Frequency, Decrement, Relaxation, and Creep across various growth stages (2, 4, 6, and 8 weeks), finding significant variations with pronounced severity at weeks 2 and 8. An increase in stiffness was observed as the broilers aged, pointing to potential growth-related or stress-induced changes affecting WB severity. A strong positive correlation was established between increased breast meat weight and WB severity, highlighting that heavier breast meat could exacerbate the condition. This correlation is vital for the poultry industry, suggesting that weight management could help mitigate WB effects. Moreover, the potential for genetic selection and breeding strategies to reduce WB occurrence was emphasized, which could aid in enhancing management practices in commercial poultry production. Collectively, these insights contribute to a deeper understanding of WB in broilers and propose avenues for future research and practical strategies to minimize its impact.

• Journal of Digestive Cancer Research
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• v.8 no.2
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• pp.102-108
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• 2020

Background: This study was performed to evaluate the effect of gastric cancer screening through analysis of screening-related data. Methods: We investigated claims data of gastric cancer from 2009 to 2015. We evaluated whether the screening was performed to prior to registration as patients with gastric cancer. The effect of gastric cancer screening was also analyzed by gender. Results: We collected total 196,293 patients with gastric cancer. 74% of them had previous experience of gastric cancer screening. In patients with screening, early gastric cancer was 33.4% and advanced gastric cancer was 17.3%. 22,548 (15.5%) patients were diagnosed with gastric cancer within 2 years after screening. In the case of patients without screening, early gastric cancer was 15.1% and advanced gastric cancer was 25.3%. In case of men, 76% of them confirmed gastric cancer through screening, and 70.2% of women confirmed the gastric cancer. In both men and women, the rate of early gastric cancer was higher among those with screening than those without screening. Conclusion: In this study, we were able to indirectly confirm the stage shift of gastric cancer screening. However, within 2 years after screening, not a few patients with gastric cancer were diagnosed. Therefore, more studies are warranted to in the future.