• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.259-267
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• 2010

In this study, the effect of particle size on the combustion characteristics of pulverized sub-bituminous coal was experimentally investigated. A laminar-flow-entrained reactor was designed and implemented to realize the desired heating ratio and temperature corresponding to the combustion atmosphere of a pulverized-coal-fueled furnace. The flame length and structure of burning particles according to different sizes were investigated. Coal combustion processes were clearly distinguished by direct visual observation of the flame structure. The onset point of volatile ignition is greatly affected by changes in the particle size, and the burning time of the volatiles is least affected by changes in the particle size. The length and instability of char flame also increase with the increase of the particle size. However, the char consumption rate within the residential time remains nearly constant.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.1-10
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• 2010

Recently heterogeneous storage system such as hybrid hard disk drive (H-HDD) combining flash memory and magnetic disk is launched, according as the read performance of NAND flash memory is enhanced as similar to that of hard disk drive (HDD) and the power consumption of NAND flash memory is reduced less than that of HDD. However, the read and write operations of NAND flash memory are slower than those of rotational disk. Besides, serious overheads are incurred on CPU and main memory in the case that intensive write requests to flash memory are repeatedly occurred. In this paper, we propose the Least Frequently Used-Hot scheme that replaces the data blocks whose reference frequency of read operation is low and update frequency of write operation is high, and the data flushing scheme that rearranges the data blocks into the multi-zone of the rotation disk. Experimental results show that the execution time of the proposed method is 38% faster than those of conventional LRU and LFU block replacement schemes in I/O performance aspect and the proposed method increases the life span of Non-Volatile Cache 40% higher than those of conventional LRU, LFU, FIFO block replacement schemes.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.3
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• pp.141-148
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• 2021

Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. It is expected that agrivoltaic systems can realize climate smart agriculture by reducing evapotranspiration and methane emission due to the reduction of incident solar radiation and the consequent surface cooling effect and bring additional income to farms through solar power generation. In this study, to evaluate that agrivoltaic systems are suitable for realization of climate smart agriculture, we conducted agro-environmental observations (i.e., downward/upward shortwave/longwave radiations, air temperature, relative humidity, water temperature, soil temperature, and wind speed) in a rice paddy under an agrivoltaic system and compared with the environment outside the system using automated meteorological observing systems (AMOS). During the observation period, the spatially averaged incoming solar radiation under the agrivoltaic system was about 70% of that in the open paddy field, and clear differences in the soil and water temperatures between the paddy field under the agrivoltaic system and the open paddy field were confirmed, although the air temperatures were similar. It is required in the near future to confirm whether such environmental differences lead to a reduction in water consumption and greenhouse gas emissions by flux measurements.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.133-138
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• 2023

Due to social phenomena such as rapid aging in Korea, nuclear familyization, single marriage, and low birth rate, the number of Companion animals and the number of households with Companion animals are increasing due to the increase in single-person households. In fact, one out of every four households has a pet, and the scale of the industry is expected to reach 6 trillion won in 2027. In particular, in a situation where the Companion animal cosmetics market is in the spotlight amid the diversification of the pet industry, there is a great lack of research on related research and industry development methods. Accordingly, this study attempted to search and analyze academic data, patented technologies, and the latest data related to pet cosmetics and provide them as basic data for the Companion animal cosmetics industry, and the results are as follows. Academic data included verification of the effectiveness of natural materials to improve the skin condition of dogs, analysis of the pet cosmetics industry, and research on ICT-converged pet cosmetics, and the industry was mainly cleaning cosmetics, with pet shampoo launches in Amorepacific, LG Household & Healthcare, and Aekyung. In the patented technology for pets, a patent has been registered for natural product material composition and formulation ratio for skin moisturizing, skin improvement, thinning, and inflammation symptom relief. As a result of this award, it was confirmed that research and development are still insufficient compared to the consumption demand of the pet cosmetics market, and it is believed that industry analysis and development research in related fields should be actively carried out.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.672-680
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• 2023

Weight is a critical factor in the ship design process given that it has a substantial impact on the hydrodynamic performance of ships. Typically, ships are optimally designed for specific conditions with a fixed draft and displacement. However, in reality, weight and draft can vary within a certain range owing to operational activities, such as fuel consumption, ballast adjustments, and loading conditions . Therefore, we investigated how resistance changes under three different loading conditions, namely overload, design-load, and lightship, for small craft, using both model experiments and numerical simulations. Additionally, we examined the sensitivity of weight changes to resistance to enhance the performance of ships, ultimately reducing power requirements in support of the International Maritime Organization's (IMO) goal of reducing CO2 emissions by 50% by 2050. We found that weight changes have a more significant impact at low Froude Numbers. Operating under overload conditions, which correspond to a 5% increase in draft and an 11.1% increase in displacement, can lead to a relatively substantial increase in total resistance, up to 15.97% and 14.31% in towing tests and CFD simulations, respectively.

• Korean Journal of Culture and Social Issue
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• v.9 no.spc
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• pp.35-55
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• 2003

The purpose of this study is to review the previous studies on the safety problems in Korea and to propose a psychological total safety system model. The model consisted of four agents; the government as the safety management agent, the suppliers of safety goods and services, consumer of safety goods and services, and civil movement institutions for safety. It was emphasized that the culture specific social representations of safety and accident have emerged in the course of rapid industrialization process in Korea during last 30 years. We delineated the social representations of the Korean people on safety and accident according to the model. A psychological analysis of drinking and driving behavior was performed as an application of the model. It was emphasized that safety psychologists have to develope and to apply the knowledge and the information from human engineering psychology and applied social psychology on safety and accidents.

• Food Science and Preservation
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• v.30 no.2
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• pp.334-346
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• 2023

The antioxidant ability of 80% ethanolic extract of nutmeg seed (NM80) was evaluated using in vitro assays and bulk oil and oil-in-water (O/W) emulsion matrices. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging, and oxygen radical antioxidant capacity (ORAC) in vitro assays were used to evaluate the antioxidant ability of the extract. The DPPH radical scavenging activities of 25, 50, 100, and 200 ㎍/mL NM80 were 12.5, 20.9, 35.1, and 62.8%, respectively, while the ABTS cation radical scavenging activities were 2.7, 6.5, 30.5, and 29.8%, respectively, demonstrating a dose-dependent effect. The ORAC value was significantly higher at an NM80 concentration of 25 ㎍/mL than the positive control (p<0.05). The conjugated dienoic acid (CDA), ρ-anisidine, and tertiary butyl alcohol values in 90-min-heated corn oil containing 200 ppm of NM80 were significantly reduced by 3.26, 16.94, and 17.34%, respectively, compared to those for the sample without NM80 (p<0.05). However, the headspace oxygen content and CDA value in the O/W emulsion containing 200 ppm of NM80 at 60℃ had 6.29 and 82.85% lower values, respectively, than those for the sample without NM80 (p<0.05). The major volatile compounds of NM80 were allyl phenoxyacetate, eugenol acetate, and eugenol. NM80 could be an effective natural antioxidant in lipid-rich foods in bulk oil or O/W emulsion matrix.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.239-250
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• 2020

The purpose of this paper is to explore the influence of the "contextualization" effect of web celebrity live broadcast on the e-commerce platform on consumers' perception of product value, risk and purchase intention. Live in this paper, using Taobao shopping consumers as the research object, the survey method, questionnaire survey is adopted, the form through the questionnaire and distributed network, a live in order to further validation of web celebrity effect of contextualized actual influence on consumer purchase intention, questionnaire design the Likert scale, seven and recycling questionnaire analysis using the statistical software SPSS 23.0 and AMOS 22.0 after processing the data. After determining the reliability and validity of the questionnaire, the exploratory factor analysis was used to verify the hypothesis and calculate the actual adjustment degree of the "contextualization" effect of web celebrity live broadcasting on consumers' purchase intention. The research results of this paper are summarized as follows :(1) consumers' perceived value of products can significantly positively affect their purchase intention, while perceived risk has a significantly negative impact on their purchase intention; (2) consumers' trust and purchase intention to products are regulated by the "contextualization" of web celebrity live broadcast. Specifically, for web celebrity live broadcasting with good "contextualization" effect, the perceived value of consumer products has a positive impact on product trust, which is higher than that of web celebrity live broadcasting with poor "contextualization" effect. In terms of resolving consumers' perceived risks to products, web celebrity live broadcast with good "contextualization" effect is also significantly better than web celebrity live broadcast with poor "contextualization" effect. Based on empirical analysis, this paper concludes that web celebrity live broadcasting will become a new breakthrough for the sustainable growth of the e-commerce industry, and puts forward Suggestions on the e-commerce marketing mode and the transformation of web celebrity live broadcasting industry.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.45-53
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• 2005

The objective of this study is to evaluate the effects of changes in soil temperature on biodegradation rate of diesel compounds from a field pilot test using hot air injection process. Total remediation time was estimated from in-situ biodegradation rate and temperature for optimum biodegradation. All tests were conducted by measuring in-situ respiration rates every about 10 days on highly contaminated area where an accidental diesel release occurred. The applied remediation methods were hot air injection/extraction process to volatilize and extract diesel compounds followed by a bioremediation process to degrade residual diesels in soils. Oxygen consumption rate varied from 2.2 to 46.3%/day in the range of 26 to $60^{\circ}C$, and maximum $O_2$ consumption rate was observed at $32.0^{\circ}C$. Zero-order biodegradation rate estimated on the basis of oxygen consumption rates varied from 6.5 to 21.3 mg/kg-day, and the maximum biodegradation rate was observed at $32^{\circ}C$ as well. In other temperature range, the values were in the decreasing trend. The first-order kinetic constants (k) estimated from in-situ respiration rates measured periodically were 0.0027, 0.0013, and $0.0006d^{-1}$ at 32.8, 41.1, and $52.7^{\circ}C$, respectively. The estimated remediation time was from 2 to 9 years, provided that final TPH concentration in soils was set to 870 mg/kg.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2014.10a
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• pp.1-24
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• 2014

This study uses geo-spatial crop modeling to quantify the biophysical impact of weather extremes. More specifically, the study analyzes the weather extreme which affected maize production in the USA in 2012; it also estimates the effect of a similar weather extreme in 2050, using future climate scenarios. The secondary impact of the weather extreme on food security in the developing world is also assessed using trend analysis. Many studies have reported on the significant reduction in maize production in the USA due to the extreme weather event (combined heat wave and drought) that occurred in 2012. However, most of these studies focused on yield and did not assess the potential effect of weather extremes on food prices and security. The overall goal of this study was to use geo-spatial crop modeling and trend analysis to quantify the impact of weather extremes on both yield and, followed food security in the developing world. We used historical weather data for severe extreme events that have occurred in the USA. The data were obtained from the National Climatic Data Center (NCDC) of the National Oceanic and Atmospheric Administration (NOAA). In addition we used five climate scenarios: the baseline climate which is typical of the late 20th century (2000s) and four future climate scenarios which involve a combination of two emission scenarios (A1B and B1) and two global circulation models (CSIRO-Mk3.0 and MIROC 3.2). DSSAT 4.5 was combined with GRASS GIS for geo-spatial crop modeling. Simulated maize grain yield across all affected regions in the USA indicates that average grain yield across the USA Corn Belt would decrease by 29% when the weather extremes occur using the baseline climate. If the weather extreme were to occur under the A1B emission scenario in the 2050s, average grain yields would decrease by 38% and 57%, under the CSIRO-Mk3.0 and MIROC 3.2 global climate models, respectively. The weather extremes that occurred in the USA in 2012 resulted in a sharp increase in the world maize price. In addition, it likely played a role in the reduction in world maize consumption and trade in 2012/13, compared to 2011/12. The most vulnerable countries to the weather extremes are poor countries with high maize import dependency ratios including those countries in the Caribbean, northern Africa and western Asia. Other vulnerable countries include low-income countries with low import dependency ratios but which cannot afford highly-priced maize. The study also highlighted the pathways through which a weather extreme would affect food security, were it to occur in 2050 under climate change. Some of the policies which could help vulnerable countries counter the negative effects of weather extremes consist of social protection and safety net programs. Medium- to long-term adaptation strategies include increasing world food reserves to a level where they can be used to cover the production losses brought by weather extremes.