• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.329-329
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• 2022

Accurate characterization of terrestrial precipitation variation from high spatial resolution satellite sensors is beneficial for urban hydrology and microscale agriculture modeling, as well as natural disasters (e.g., urban flooding) early warning. However, the widely-used top-down approach for precipitation retrieval from microwave satellites is limited in several hydrological and agricultural applications due to their coarse spatial resolution. In this research, we aim to apply a novel bottom-up method, the parameterized SM2RAIN, where precipitation can be estimated from soil moisture signals based on an inversion of water balance model, to generate high spatial resolution terrestrial precipitation estimates at 0.01º grid (roughly 1-km) from the C-band SAR Sentinel-1. This product was then tested against a common reanalysis-based precipitation data and a domestic rain gauge network from the Korean Meteorological Administration (KMA) over central South Korea, since a clear difference between climatic types (coasts and mainlands) and land covers (croplands and mixed forests) was reported in this area. The results showed that seasonal precipitation variability strongly affected the SM2RAIN performances, and the product derived from separated parameters (rainy and non-rainy seasons) outperformed that estimated considering the entire year. In addition, the product retrieved over the mainland mixed forest region showed slightly superior performance compared to that over the coastal cropland region, suggesting that the 6-day time resolution of S1 data is suitable for capturing the stable precipitation pattern in mainland mixed forests rather than the highly variable precipitation pattern in coastal croplands. Future studies suggest comparing this product to the traditional top-down products, as well as evaluating their integration for enhancing high spatial resolution precipitation over entire South Korea.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.4 no.4
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• pp.146-153
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• 2023

This study aimed to conduct a comprehensive survey of social wasp diversity and its impacts on remote Ulleungdo Island, South Korea. A total of 12 wasp traps were placed across the island, and specimens were collected monthly from May to October. Additional collection was conducted by thoroughly inspecting the areas surrounding the traps. The traps yielded a total of 5,068 individuals, representing two genera and two species. A total of 3,961 Vespa simillima simillima Smith individuals (78.2%) were collected, and 1,107 individuals (21.8%) were identified as Vespula flaviceps flaviceps Smith. Additionally, five individuals of Polistes snelleni de Saussure were collected through sweeping, bringing the total to 5,132 individuals of three genera and three species. It is worth noting that our findings indicate potential misidentifications in the species list of Vespidae found in the literature. Emergency services call centers reported the removal of 60 social wasp nests on Ulleungdo Island between 2018 and 2022, with the highest number of reports occurring from July to September, accounting for 87% of all cases. Dodong-ri and Jeodong-ri, with the highest populations, reported the most incidents, although fortunately, there have been no recent injuries. Past incidents involving the destruction of dried squid products by Vespula species have resulted in significant economic losses, underscoring the need for preventative measures. Furthermore, ongoing surveillance of hornet invasions is essential to safeguard the Jangwon bees being reared on Ulleungdo Island.

• Journal of the Korean Wood Science and Technology
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• v.52 no.1
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• pp.1-12
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• 2024

Betung bamboo (Dendrocalamus asper) is used as a building and handicraft material in Indonesia; however, bamboo needs to be dried to increase its stability. This study aimed to evaluate the efficiency of drying bamboo using solar energy and different drying oven designs. The betung bamboo pieces were dried using a direct solar dryer (direct drying) and an indirect solar dryer (indirect drying) and then the decrease in levels that occurred based on the relative humidity (RH) and temperature values achieved in the two dryers were compared. The highest average temperature in the direct indirect drying oven compartment was 60.1 ± 13.1℃ with 19.9 ± 16.4% RH and 60.2 ± 11.9℃ with 19.5 ± 15.5% RH, respectively. The drying defect in indirect drying was lower than that in direct drying, and indirect drying had a 61.7% greater average water loss than direct drying with significant difference (95%, analysis of variance) based on water loss/compartment volume parameters. Thus, the solar drying oven can be used to air-dry bamboo (14%) for 7 d from an initial moisture content of 70%-80% in bamboo strips. The results of this research can be used for small-scale bamboo processing industries that have limited use of electrical energy with quite good results.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.358-383
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• 2015

The concept of 'carbon footprint' has been developed as a means of quantifying the specific emissions of the greenhouse gases (GHGs) that cause global warming. Although there are still neither clear definitions of the term nor rules for units or the scope of its estimation, it is broadly accepted that the carbon footprint is the total amount of GHGs, expressed as $CO_2$ equivalents, emitted into the atmosphere directly or indirectly at all processes of the production by an individual or organization. According to the ISO/TS 14067, the carbon footprint of a product is calculated by multiplying the units of activity of processes that emit GHGs by emission factor of the processes, and by summing them up. Based on this, 'carbon labelling' system has been implemented in various ways over the world to provide consumers the opportunities of comparison and choice, and to encourage voluntary activities of producers to reduce GHG emissions. In the agricultural sector, as a judgment basis to help purchaser with ethical consumption, 'low-carbon agricultural and livestock products certification' system is expected to have more utilization value. In this process, the 'cradle to gate' approach (which excludes stages for usage and disposal) is mainly used to set the boundaries of the life cycle assessment for agricultural products. The estimation of carbon footprint for the entire agricultural and forestry sector should take both removals and emissions into account in the "National Greenhouse Gas Inventory Report". The carbon accumulation in the biomass of perennial trees in cropland should be considered also to reduce the total GHG emissions. In order to accomplish this, tower-based flux measurements can be used, which provide a direct quantification of $CO_2$ exchange during the entire life cycle. Carbon footprint information can be combined with other indicators to develop more holistic assessment indicators for sustainable agricultural and forestry ecosystems.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.2
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• pp.107-117
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• 2004

If doubtlessly contributes much to agriculture and rural development. The roles can be summarized as; 1. to activate rural areas and to provide more comfortable and safe rural life with equivalent services to those in urban areas, facilitating distance education, tole-medicine, remote public services, remote entertainment etc. 2. To initiate new agricultural and rural business such as e-commerce, real estate business for satellite officies, rural tourism and virtual corporation of small-scale farms. 3. To support policy-making and evaluation on optimal farm production, disaster management, effective agro-environmental resource management etc., providing tools such as GIS. 4. To improve farm management and farming technologies by efficient farm management, risk management, effective information or knowledge transfer etc., realizing competitive and sustainable farming with safe products. 5. To provide systems and tools to secure food traceability and reliability that has been an emerging issue concerning farm products since serious contamination such as BSE and chicken flu was detected. 6. To take an important and key role for industrialization of farming or lam business enterprise, combining the above roles.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.397-405
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• 2009

In this study, we investigated the potential of producing bioethanol from Liriodendron tulipifera by using oxalic acid pretreatment. Amounts of fermentable sugars, mostly xylose and glucose, in the liquid fraction (hydrolysate) was $40.22g/{\ell}$ after the biomass was pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$. Production amounts of ethanol was $8.6g/{\ell}$ from the 72 hours of simultaneous saccharification and fermentation (SSF) on solid fraction of the pretreated sample. At the same condition, when the reaction time increased to 40 minutes, $32.66g/{\ell}$ of fermentable sugars in the hydrolysate and $9.5g/{\ell}$ of ethanol was produced from the process of pretreatment and SSF. As a result of analyzing the fermentation inhibitors, such as acetic acid, 5-HMF, furfural and total phenolic compounds, as the reaction time increased, the amount of the fermentation inhibitors in the hydrolysate increased. Production of the fermentation inhibitors was more affected by initial concentration of oxalic acid rather than reaction time. $3.39{\sim}5.78g/{\ell}$ of acetic acid was produced by pretreatment with 0.013 g/g of oxalic acid, and the amount of furfural produced by decomposition of xylose was 2~3 times higher than the amount of 5-HMF produced by decomposition of glucose. All the hydrolysates contained more than $5g/{\ell}$ of total phenols considered as the degradation product of lignin. Therefore, by analyzing the amount of fermentable sugars and fermentation inhibitors in the hydrolysate, and producing ethanol from SSF of solid fraction of the pretreated sample, the biomass pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$ can be expected to produce the most ethanol.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.374-380
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• 2015

The quality characteristics of the woodpellet manufactured from two domestic pines (Pinus densiflora S. et Z. and Pinus rigida Mill.) were investigated for the efficient energy use of woody biomass resources. Properties of woodpellets such as moisture content, heating value, ash content, apparent density and durability were determined by using the standard test method of woodpellets of Korea Forest Research Institute (KFRI) and elemental analysis. The results of elemental analysis for C, H, O and N showed 61.42% carbon, 5.56% hydrogen, 32.87% oxygen, and 0.15% nitrogen for Pinus densiflora S. et Z. and 61.03% carbon, 5.96% hydrogen, 32.83% oxygen, and 0.18% nitrogen for Pinus rigida Mill. No significant difference between Pinus densiflora S. et Z. and Pinus rigida Mill was observed on elemental analysis. Heating values of each woodpellet were ranged from 19.00 to 19.42 MJ/kg which satisfied the first grade quality standard (${\geq}18.0MJ/kg$) by KFRI. The ash contents of woodpellet were slightly different between Pinus densiflora S. et Z. and Pinus rigida Mill., and satisfied the first grade quality standard (${\leq}0.7%$) by KFRI. Apparent density of woodpellet (Pinus densiflora S. et Z.) was passed the first grade standard level (${\geq}640kg/m^3$), and woodpellets from Pinus rigida Mill. satisfied the second grade quality of the standard. The moisture contents of each woodpellet were satisfied by the first grade quality standard (${\leq}10%$). The durability of woodpellet (Pinus densiflora S. et Z.) was passed the third grade level (${\geq}95%$), but Pinus rigida Mill. woodpellet was insufficient to satisfy the quality standard.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.378-388
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• 2012

This study was carried out to investigate the optimum condition for sap exudation of Juglans mandshurica in comparison with Acer mono Max. trees in a site of Inje-Gun, Gangwon-Do, Korea. Amount of sap exudation, air temperature, relative air humidity and tree diameter at breast height (DBH) were monitored for the period of February 1 through March 31, 2008, and correlation analysis of several factors affecting on sap exudation was carried out. Sap exudation from J. mandshurica initiated on Feb. 28 as the same time in case of A. mono and continued for a month, and enhanced in early March compared to around the middle of March for A. mono. The amount of sap of A. mono was linearly proportional to the diameter at breast height (DBH) but there was no apparent relationship for J. mandshurica. As the amount of sap exudation per tree increased then sap exudation per unit DBH was also linearly proportional in both J. mandshurica and A. mono. The amount of sap exudation per unit DBH of J. manshurica were $0.3{\pm}0.1{\ell}/cm$ on average, which was one third times of $0.9{\pm}0.1{\ell}/cm$ for A. mono. During the days of enhanced sap exudation, the atmospheric conditions such as air temperature and relative humidity around J. manshurica trees were very similar with those of A. mono. The minimum temperature was a significant factor affecting the amount of sap of J. mandshurica whereas the range of temperature was the principal factor for A. mono. In conclusion, the sap of J. mandshurica exudated in atmospheric conditions similar to A. mono, but the amount of sap was affected by different atmospheric factors compared to A. mono.

• Journal of the Korean Wood Science and Technology
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• v.49 no.1
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• pp.23-43
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• 2021

In this study, we selected two essential oils, Citrus unshiu and Cinnamomum cassia with superior antioxidant effects from the essential oils of 7 wild plants in South Korea and examined their antimicrobial activity against Candida albicans, which causes dermatitis to identify the antimicrobial components in the essential oils. As a result of measuring DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, SC50 value of the Citrus unshiu essential oil was 0.010 mg/mL, while for the Cinnamomum cassia essential oil, SC50 value was 0.09 mg/mL. In addition, when ABTS (2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was measured, SC50 value of the Citrus unshiu essential oil was 0.09 mg/mL, while for the Cinnamomum cassia essential oil, it was 0.06 mg/mL, exhibiting high antioxidant activity. For the minimum inhibitory concentration (MIC), the essential oil of Cinnamomum cassia was 1.25 mg/mL and that of Citrus unshiu was 5 mg/mL, demonstrating a high antimicrobial activity of the Cinnamomum cassia essential oil. Through the thin layer chromatography (TLC) bioassay, we assessed the antimicrobial activity against C. albicans according to the fraction components of the two essential oils. Also, by using preparative TLC (prep. TLC), we obtained the active fractions, and by performing GC/MS analysis of the components with the same Rf value, we identified the antimicrobial-active components. As a result, the main components having antioxidant and antimicrobial activities were cinnamyl acetate, eucalyptol, linalool, and citral of the Cinnamomum cassia essential oil and linalool from the Citrus unshiu essential oil. Also, based on the analysis of the fractional components that showed antioxidant and antimicrobial activities in both of the two essential oils, it was found that linalool has antioxidant activity, while cinnamyl acetate, eucalyptol, citral, and geranyl acetate have antioxidant and antimicrobial activities.

• Journal of Intelligence and Information Systems
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• v.24 no.4
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• pp.67-83
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• 2018

The Korean film industry with significant increase every year exceeded the number of cumulative audiences of 200 million people in 2013 finally. However, starting from 2015 the Korean film industry entered a period of low growth and experienced a negative growth after all in 2016. To overcome such difficulty, stakeholders like production company, distribution company, multiplex have attempted to maximize the market returns using strategies of predicting change of market and of responding to such market change immediately. Since a film is classified as one of experiential products, it is not easy to predict a box office record and the initial number of audiences before the film is released. And also, the number of audiences fluctuates with a variety of factors after the film is released. So, the production company and distribution company try to be guaranteed the number of screens at the opining time of a newly released by multiplex chains. However, the multiplex chains tend to open the screening schedule during only a week and then determine the number of screening of the forthcoming week based on the box office record and the evaluation of audiences. Many previous researches have conducted to deal with the prediction of box office records of films. In the early stage, the researches attempted to identify factors affecting the box office record. And nowadays, many studies have tried to apply various analytic techniques to the factors identified previously in order to improve the accuracy of prediction and to explain the effect of each factor instead of identifying new factors affecting the box office record. However, most of previous researches have limitations in that they used the total number of audiences from the opening to the end as a target variable, and this makes it difficult to predict and respond to the demand of market which changes dynamically. Therefore, the purpose of this study is to predict the weekly number of audiences of a newly released film so that the stakeholder can flexibly and elastically respond to the change of the number of audiences in the film. To that end, we considered the factors used in the previous studies affecting box office and developed new factors not used in previous studies such as the order of opening of movies, dynamics of sales. Along with the comprehensive factors, we used the machine learning method such as Random Forest, Multi Layer Perception, Support Vector Machine, and Naive Bays, to predict the number of cumulative visitors from the first week after a film release to the third week. At the point of the first and the second week, we predicted the cumulative number of visitors of the forthcoming week for a released film. And at the point of the third week, we predict the total number of visitors of the film. In addition, we predicted the total number of cumulative visitors also at the point of the both first week and second week using the same factors. As a result, we found the accuracy of predicting the number of visitors at the forthcoming week was higher than that of predicting the total number of them in all of three weeks, and also the accuracy of the Random Forest was the highest among the machine learning methods we used. This study has implications in that this study 1) considered various factors comprehensively which affect the box office record and merely addressed by other previous researches such as the weekly rating of audiences after release, the weekly rank of the film after release, and the weekly sales share after release, and 2) tried to predict and respond to the demand of market which changes dynamically by suggesting models which predicts the weekly number of audiences of newly released films so that the stakeholders can flexibly and elastically respond to the change of the number of audiences in the film.