• 한국수산과학회지
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• 제34권4호
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• pp.348-354
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• 2001

This study was conducted to estimation of change characteristics for water quality by the dyke gate operation in the Keum River estuary. The estimation data made use of surveyed data in Keum River estuary by NERDI (National Fisheries Research and Development Institute) during $1990\~1999$. Shown to compare water quality changes at st. A and st. D in Figure 1, the concentrations of TSS, COD and nutrients at st. A were as high as about $2\~4$ times than those at st. D due to affection of fresh water discharge in the Keum River. The percentages of water quality change at surface water by dyke gate operation in the Keum River estuary were shown that TSS (Total Suspended Solid) was decrease to $56\%,\;47\%$ at st. A and D, and COD (Chemical Oxygen Demand) was increase to $68\%,\;71\%$ at st. A and D, respectively. The changes percentage of DIN (Dissolved Inorganic Nitrogen) by dyke gate operation in the Keum River estuary were increase high to $95\%$ at surface water and $7\sim30\%$ at bottom water, but those of DIP (Dissolved Inorganic Phosphorus) were increase to $2.8\sim8.6\%$ at surface water and $28\%$ at bottom water. The range of fluctuation for water quality at each station by dyke gate operation has shown that salinity and TSS are little better than before dyke gate operation, but COD show highly fluctuation. Also we studied estimation of characteristics of water quality change by the season, COD was increased except the summer, TSS was decreased to all season. DIN was increased to about $61\sim172.1\%$ for all season, but DIP was increased to the spring and decreased to the autumn, DIN enrichment in the estuary by dyke gate operation are interpreted to improvement of organic matter decomposition and nitrification by increasing the residence time and to increase nutrient flux in sediments due to decreasing dissolved oxygen and increasing a deposit matter.

• Journal of Biosystems Engineering
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• 제30권4호
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• pp.235-241
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• 2005

For better and large utilization of rice husk, the production and consumption status, differences in chemical composition and heating value due to region and variety, and thermogravimetric characteristic of rice husk were studied. In addition, the differences in chemical composition due to region and variety and the crystallization characteristic of rice husk ash were also studied. Approximately 800,000 M/T of rice husk was produced per year in Korea, which is about $18\%$ of the paddy production by weight. Noticeable varietal and regional difference pattern in chemical composition was not found among the domestic rice husk samples. Their average ash content and higher heating value were $16.4\%$ and 16,660 kJ/kg by dry basis, respectively. A relation seemed to exist between the carbon content and higher heating value. Noticeable difference pattern in chemical composition was not found among the domestic rice husk ash samples. The $SiO_2$ contents were a little low, the maximum being $92.9\%,$ and the contents of major components such as CaO, MgO, and $K_2O$ were also lower compared with foreign rice husk ash due to the deficiency of compost matters in domestic soils. Thermogravimetry study showed the thermal decomposition of rice husk started at about $250^{\circ}C,$ followed by relatively fast combustion of combustible gas until the temperature rose to $350^{\circ}C.$ After $350^{\circ}C,$ combustion of the carbon component proceeded relatively slowly as the temperature increased. Therefore, the ignition temperature of the rice husk could be estimated around $300^{\circ}C$. Crystallization of $SiO_2$ in the rice husk ash was found from the combustion temperature of $750^{\circ}C$ and became distinctly when the combustion temperature exceeded $900^{\circ}C$. The ash became darker with $SiO_2$ crystallization.

• 한국산업보건학회지
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• 제24권3호
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• pp.272-280
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• 2014

Objectives: The purpose of this study was to evaluate the characteristics of worker exposure to hazardous chemical substances and propose the direction of work environment management for protecting worker's health in the semiconductor assembly process. Methods: Four assembly lines at two semiconductor manufacturing companies were selected for this study. We investigated the types of chemicals that were used and generated during the assembly process, and evaluated the workers' exposure levels to hazardous chemicals such as benzene and formaldehyde and the current work environment management in the semiconductor assembly process. Results: Most of the chemicals used at the assembly process are complex mixtures with high molecular weight such as adhesives and epoxy molding compounds(EMCs). These complex mixtures are stable when they are used at room temperature. However workers can be exposed to volatile organic compounds(VOCs) such as benzene and formaldehyde when they are used at high temperature over $100^{\circ}C$. The concentration levels of benzene and formaldehyde in chip molding process were higher than other processes. The reason was that by-products were generated during the mold process due to thermal decomposition of EMC and machine cleaner at the process temperature($180^{\circ}C$). Conclusions: Most of the employees working at semiconductor assembly process are exposed directly or indirectly to various chemicals. Although the concentration levels are very lower than occupational exposure limits, workers can be exposed to carcinogens such as benzene and formaldehyde. Therefore, workers employed in the semiconductor assembly process should be informed of these exposure characteristics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4389-4411
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• 2018

High dynamic range (HDR) images are becoming pervasive due to capturing or rendering of a wider range of luminance, but their special display equipment is difficult to be popularized because of high cost and technological problem. Thus, HDR images must be adapted to the conventional display devices by applying tone mapping (TM) operation, which puts forward higher requirements for intellectual property protection of HDR images. As the robustness presents regional diversity in the low dynamic range (LDR) watermarked image after TM, which is different from the traditional watermarking technologies, a concept of watermarking activity is defined and used to distinguish the essential distinction of watermarking between LDR image and HDR image in this paper. Then, a novel robust HDR image watermarking algorithm is proposed against TM operations. Firstly, based on the hybrid processing of redundant discrete wavelet transform and singular value decomposition, the watermark is embedded by modifying the structure information of the HDR image. Distinguished from LDR image watermarking, the high embedding strength can cause more obvious distortion in the high brightness regions of HDR image than the low brightness regions. Thus, a perceptual brightness mask with low complexity is designed to improve the imperceptibility further. Experimental results show that the proposed algorithm is robust to the existing TM operations, with taking into account the imperceptibility and embedded capacity, which is superior to the current state-of-art HDR image watermarking algorithms.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.330-341
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• 2017

Tropical forests play a key role for functioning of the planet and maintenance of life. These forests support more than half of the world's species, serve as regulators of global and regional climate, act as carbon sinks and provide valuable ecosystem services. Forest floor biomass and litterfall dynamics was measured in different sites influenced by fire in a seasonally dry tropical forest of Bhoramdeo wildlife sanctuary of Chhattisgarh, India. The forest floor biomass was collected randomly placed quadrats while the litterfall measured by placing stone-block lined denuded quadrat technique. The seasonal mean total forest floor biomass across the fire regimes varied from $2.00-3.65t\;ha^{-1}$. The total litterfall of the study sites varied from $4.75-7.56t\;ha^{-1}\;yr^{-1}$. Annual turnover of litter varied from 70-74% and the turnover time between 1.35-1.43 years. Monthly pattern of forest floor biomass indicated that partially decayed litter, wood litter and total forest floor were differed significantly. The seasonal variation showed that leaf fall differed significantly in winter season only among the fire regimes while the wood litter was found non significant in all the season. This study shows that significant variation among the site due to the forest fire. Decomposition is one of the ecological processes critical to the functioning of forest ecosystems. The decomposing wood serves as a saving account of nutrients and organic materials in the forest floor. Across the site, high fire zone was facing much of the deleterious effects on forest floor biomass and litter production. Control on such type of wildfire and anthropogenic ignition could allow the natural recovery processes to enhance biological diversity. Chronic disturbances do not provide time for ecosystem recovery; it needs to be reduced for ecosystem health and maintaining of the high floral and faunal biodiversity.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1778-1790
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• 2018

Based on the requirements and characteristics of multi-zone autonomous decision-making in modern power system, fully distributed computing methods are needed to optimize the economic dispatch (ED) problem coordination of multi-regional power system on the basis of constructing decomposition and interaction mechanism. In this paper, four fully distributed methods based on alternating direction method of multipliers (ADMM) are used for solving the ED problem in distributed manner. By duplicating variables, the 2-block classical ADMM can be directly used to solve ED problem fully distributed. The second method is employing ADMM to solve the dual problem of ED in fully distributed manner. N-block methods based on ADMM including Alternating Direction Method with Gaussian back substitution (ADM_G) and Exchange ADMM (E_ADMM) are employed also. These two methods all can solve ED problem in distributed manner. However, the former one cannot be carried out in parallel. In this paper, four fully distributed methods solve the ED problem in distributed collaborative manner. And we also discussed the difference of four algorithms from the aspects of algorithm convergence, calculation speed and parameter change. Some simulation results are reported to test the performance of these distributed algorithms in serial and parallel.

• 수산경영론집
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• 제52권1호
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• pp.47-63
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• 2021

The purpose of this study is to identify the leading price between Jeju and Wando's oliver flounder producer price and to analyze the dynamic effect of the regional producer price using the panel VAR model. In the process of analysis, it was confirmed that there are unit roots in the monthly data of Jeju and Wando's oliver flounder producer price. So, in order to avoid spurious regression, the rate change of producer price which carries out log difference was used in the analysis. As a result of the analysis, first, the panel Granger causality test showed that the influence of the change rate of producer price in oliver flounder in Jeju was slightly larger than that in Wando, but it was found that each region all leads the change rate of the producer price in oliver flounder. Second, the panel VAR estimation showed that the rate change of producer price in Jeju and Wando a month ago had a statistically significant effect on the change rate of producer price of each region. Third, the impulse response analysis indicated that other regions are affected a little more than the same region in case of the occurrence of the impact on the error terms of the change rate of produce price in Jeju and Wando oliver flounder. Fourth, the variance decomposition analysis showed that the change rate of producer price in the two regions was higher explained by Jeju compared to Wando. In conclusion, it is expected that the above results can not only be useful as basic data for the stabilization of oliver flounder producer price and the establishment of policies for easing volatility but can also help the oliver flounder industry operate its business.

• Journal of Korea Trade
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• 제26권4호
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• pp.23-38
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• 2022

Purpose - This paper empirically explores the RCA of electrical equipment trade between China and Korea from the perspective of gross trade and value-added trade. The goal of this paper is to scan the electrical equipment's RCA, the decomposition of gross exports, and the impacts of an exerted shock. Design/methodology - We applied the domestic value-added method in measuring the RCA, which could be more accurate than traditional RCA since it excludes foreign value-added. Based on the research purpose, this paper follows the framework of Koopman, Wang, and Wei (2014)-as extended by Wang, Wei, and Zhu (2018). It extracts the data from the 2019 Multi-regional Input-Output (MRIO) databases compiled by the Asian Development Bank in January 2021. Findings - After rigorous examination, the main findings are as follows: First, the electrical equipment sector maintains a consistent comparative advantage in either assessing method. Second, China exports more gross goods of electrical equipment to the world than South Korea does, but there is a trade deficit with Korea. Third, South Korea and P.R. China are the most significant bilateral partners of foreign value-added sourcing. Finally, it is surprising that there is a shock on electrical equipment; the partner's service, as well as manufacturing sectors, would be affected. Originality/value - This paper explores the revealed comparative advantage between Korea and China from traditional gross export and value-added perspectives. Second, we apply the information from the 2019 MRIO database compiled by the Asian Development Bank in January 2021, reflecting the current situation. Third, this paper analyzes the electrical equipment and the impacts on other parties' sectors. Finally, we carry out the subjects that deserve to be investigated in the future.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.252-252
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• 2022

Genotype-by-environment interaction (GEI) refers to the comparative response of genotypes to different environments conditions. Thus, understanding GEI is a fundamental component for selecting superior genotypes for breeding programs. The significance of utilizing early maturing cultivars not only provides flexibility in planting dates, but also serves as an effective strategy to reduce methane emission from the paddy fields. In this study, we conducted multi-environment trials (METs) to evaluate yield-related traits such as culm length, panicle length, panicle number, spikelet per plant, and thousand grain weight. A total of eighty-one Korean commercial rice cultivars categorized as early maturing cultivars, were cultivated in three regions, two planting seasons for two years. The genotype main effect plus genotype-by-environment interaction (GGE) biplot analysis of yield-related traits and grain yield explained 70.02-91.24% of genotype plus GEI variation, and exhibited various patterns of mega-environment delineation, discriminating ability, representativeness, and genotype rankings across the planting seasons and environments. Moreover, simultaneous selection using weighted average of absolute scores from the singular value decomposition (WAASB) and multi-trait stability index (MTSI) revealed six highly recommended genotypes with high stability and crop productivity. The winning genotypes under specific environment can be utilized as useful genetic materials to develop regional specialty cultivars, and recommended genotypes can be used as elite climate-resilient parents to improve yield-potential and reduce methane emission as part to accomplish carbon-neutrality.

• 한국경제지리학회지
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• 제20권1호
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• pp.1-15
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• 2017

본 연구는 2005-2013년간 울산지역의 성장을 견인하고 있는 3대 주력산업(석유화학산업, 조선산업, 자동차산업)이 어떠한 요인에 의해 성장하였는지를 투입산출 구조분해분석법을 통해 실증적으로 분석한 것이다. 이를 위해 한국은행에서 공표한 지역산업연관표를 이용하여 3대 주력산업의 구조변화를 살펴보고, 각 산업의 요인별 성장기여율을 최종수요, 수출수요, 최종재수입대체, 중간재수입대체, 기술변화 등으로 구분하여 분석하였다. 울산의 3대 주력산업 중 석유화학산업과 자동차산업의 총산출과 총수요 증가율은 2005-2010년에 비해 2010-2013년에 증가하였지만, 조선산업의 총산출과 총수요 증가율은 둔화된 것으로 나타났다. 3대 주력산업의 총산출 증가에 대한 요인별 성장기여율 분석한 결과, 수출수요가 가장 큰 영향을 미치는 것으로 나타났다. 산업별로 살펴보면, 석유화학산업은 수출수요 성장기여율이 2005-2010년에 209.23%, 2010-2013년에 113.78%로 가장 큰 비중을 차지하였다. 자동차산업은 수출수요 성장기여율이 2005-2010년에 258.72%, 2010-2013년에 72.69%의 비중을 차지하였고, 기술변화 성장기여율은 2005-2010년에 -115.36%에서 2010-2013년에 16.91%로 크게 증가하였다. 반면 조선산업은 2005-2010년에 수출수요 성장기여율이 94.47%로 가장 큰 비중을 차지하였으나 2010-2013년에는 -255.32%로 크게 감소하였고, 최종수요 성장기여율도 2005-2010년에 1.75%에서 2010-2013년에 -502.65%로 급감하였으나, 최종재수입대체와 기술변화 성장기여율은 280.68%와 492.21%로 크게 증가하였다. 울산의 3대 주력산업의 성장요인 분석은 관련 산업정책을 재정리하고 수립하는데 기초자료로서 역할을 할 것으로 기대한다.