• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.105-113
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• 2019

A two-year study was conducted from 2017 to 2018 by the establishment of a test field at Chungju-si and Cheongyang-gun. Plant height, number of leaves, insects and diseases, and fresh and dry matter yields for corn hybrid('Kwangpyeongok') were investigated. Daily average, maximum, and minimum temperature, monthly average temperature, daily precipitation, and sunshine duration during the growing season were investigated. We selected climate-critical factors to corn productivity and conducted an evaluation of vulnerability to climate change from 1999 to 2018 for both regions. In 2018, the dry matter yield of forage corn was 6,475 and 7,511 kg/ha in Chungju and Cheongyang, respectively, which was half of that in 2017. The high temperature and drought phenomenon in the 2018 summer caused the corn yield to be low. As well as temperature, precipitation is an important climatic factor in corn production. As a result of climate impact vulnerability assessment, the vulnerability has increased recently compared to the past. It is anticipated that if the high temperature phenomenon and drought caused by climate change continues, a damage in corn production will occur.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.37 no.2
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• pp.20-29
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• 2019

The purpose of this study is to verify and reconstruct the record information for big old trees of Jeju on the basis of the precise map of Jeju island in 1918 which was produced 100 years ago. For the analysis of high altitude, coordinate system and georeferencing were performed by selecting representative points using ArcGIS. We extracted digitized information by using point extraction method and extracted attribute information based on legend type and relative size in map. Based on the map of the past 100 years ago, the present situation of the big old tree in Jeju was analyzed and their characteristics were analyzed. In addition, based on the information of the protected big old trees in present, we discussed the characteristics of past tree (1918), present tree (2019), and contribution of big old tree in Jeju landscape and vegetation. As a result, 1,013 individuals were distributed in Jeju Island 100 years ago. Even when it was intensive in the use of timber, the big old trees were protected, and contributed as a representative component of Jeju's unique landscape. The remaining distribution of Jeju's big old tree is 159 trees. As in the past, distribution has been confirmed around the lowlands, but declines in numbers are found throughout the island. The major factors for the decline of individuals are large-scale development projects such as reaching the limit of life, natural disturbance (typhoon, disease, pest, drought, etc.). However, it is presumed that a large number of individuals have played a leading role in shaping the current forests as contributing to important species sources in the restoration process of Jeju vegetation. However, it is presumed that a large number of individuals (405) have played a leading role in forming the present forest by contributing to the species pool in the restoration process of Jeju vegetation.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.871-877
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• 2018

Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. $CO_2$ methanation is well known reaction that as a renewable energy storage system. $CO_2$ methanation requires a catalyst to be active at relatively low temperatures ($250-500^{\circ}C$) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with $Ni/{\gamma}-Al_2O_3$ (Ni70%, and ${\gamma}-Al_2O_3$30%) catalyst. The range of the reaction conditions were $H_2/CO_2$ mole ratio range of 4.0-6.0, temperature of $300-420^{\circ}C$, pressure of 1-9 bar, and gas velocity ($U_0/U_{mf}$) of 1-5. As the $H_2/CO_2$ mole ratio, temperature and pressure increased, $CO_2$ conversion increases at the experimental temperature range. However, $CO_2$ conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum $CO_2$ conversion of 99.6% was obtained with the operating condition as follows; $H_2/CO_2$ ratio of 5, temperature of $400^{\circ}C$, pressure of 9 bar, and $U_0/U_{mf}$ of 1.4-3.

• Journal of Climate Change Research
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• v.2 no.1
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• pp.55-68
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• 2011

The Intergovernmental Panel on Climate Change(IPCC) has identified the causes of climate change and come up with measures to address it at the global level. Its key component of the work involves developing and assessing future climate change scenarios. The IPCC Expert Meeting in September 2007 identified a new greenhouse gas concentration scenario "Representative Concentration Pathway(RCP)" and established the framework and development schedules for Climate Modeling (CM), Integrated Assessment Modeling(IAM), Impact Adaptation Vulnerability(IAV) community for the fifth IPCC Assessment Reports while 130 researchers and users took part in. The CM community at the IPCC Expert Meeting in September 2008, agreed on a new set of coordinated climate model experiments, the phase five of the Coupled Model Intercomparison Project(CMIP5), which consists of more than 30 standardized experiment protocols for the shortterm and long-term time scales, in order to enhance understanding on climate change for the IPCC AR5 and to develop climate change scenarios and to address major issues raised at the IPCC AR4. Since early 2009, fourteen countries including the Korea have been carrying out CMIP5-related projects. Withe increasing interest on climate change, in 2009 the COdinated Regional Downscaling EXperiment(CORDEX) has been launched to generate regional and local level information on climate change. The National Institute of Meteorological Research(NIMR) under the Korea Meteorological Administration (KMA) has contributed to the IPCC AR4 by developing climate change scenarios based on IPCC SRES using ECHO-G and embarked on crafting national scenarios for climate change as well as RCP-based global ones by engaging in international projects such as CMIP5 and CORDEX. NIMR/KMA will make a contribution to drawing the IPCC AR5 and will develop national climate change scenarios reflecting geographical factors, local climate characteristics and user needs and provide them to national IAV and IAM communites to assess future regional climate impacts and take action.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.658-673
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• 2018

Social conflicts with extremely low frequency magnetic field(ELF-MF) exposures are expected to exacerbate due to continued increase in electric power demand and construction of high voltage transmission lines(HVTL). However, in current environmental impact assessment(EIA) act, specific guidelines have not been included concretely about EIA of ELF-MF. Therefore, this study conducted a standardization study on EIA method through case analysis, field measurement, and expert consultation of the EIA for the ELF-MF near HVTL which is the main cause of exposures. The status of the EIA of the ELF-MF and the problem to be improved are derived and the EIA method which can solve it is suggested. The main contents of the study is that the physical characteristics of the ELF-MF affected by distance and powerload should be considered at all stages of EIA(survey of the current situation - Prediction of the impacts - preparation of mitigation plan ? post EIA planning). Based on this study, we also suggested the 'Measurement method for extremely low frequency magnetic field on transmission line' and 'Table for extremely low frequency magnetic field measurement record on transmission line'. The results of this study can be applied to the EIA that minimizes the damage and conflict to the construction of transmission line and derives rational measures at the present time when the human hazard to long term exposure of the ELF-MF is unclear.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.169-197
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• 2018

The purpose of this study is to present a reasonable and concrete standard for the Korean aviation insurance compulsory subscription system. Through this, we aim to improve the current revision of laws and regulations, and ultimately create an environment in which the safety and property of the Korean people who use aircraft with appropriate aviation insurance can be secured. In particular, by reviewing the aviation business law and its new laws and regulations enacted in 2017, the legislative improvement direction of aviation insurance will be proposed. In order to maintain the continuous growth of the air transportation industry and to make amicable compensation for the victims, considering the characteristics of the total accident, instantness, and giganticness of air accidents in which a lot of people and property are lost in the event of an accident, adequate insurance coverage is essential. In this respect, the compulsory insurance to amend the principle of freedom of contract, which is the great principle of the modern judicial system, will be persuasive. However, in comparison with foreign legislation, the legal provisions on Korea's obligation to comply with aviation insurance need to be revised around the following issues: First, it is reasonable to enforce the regulation of the mandatory aviation insurance by legislation from the Congress not by administrative regulations. Because it will force the monetary obligations of the individual such as common air carriers. Second, our law regulations respond to various kinds of air damages by using the phrase "limit of liability stipulated in international conventions". However, as we have seen in the text, the range of compensation are various according to the use of legal instruments in international conventions such as the Montreal Convention, which governs the compensation of passengers for damages to passengers today. Third, in countries with narrow territories, such as Korea, there are big differences in flying time and insurable risk between domestic and international transportation. Therefore, it is necessary to divide domestic transportation and international transportation even in the obligation to join the insurance. This dual discipline has the advantage for rookies in air carrier market who mainly start their business from domestic service. Fourth, according to Korean law, the regulations of automobile loss insurance is applicable to the aviation mandatory insurance of unmanned aerial vehicle accident which is lack of persuasion. In the future, it will be appropriate to discipline insurance for unmanned aerial vehicles with unlimited potential for development from a long-term perspective.

• 한국사회정책
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• v.23 no.2
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• pp.49-81
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• 2016

This study agrees with the idea that a situation centered perspective provides a useful contribution in understanding women's attitude on organizations. Women's occupational experiences are less related to their "femaleness" than to the structural constraints inherent in the occupational positions women fill. So characteristics of the organizational situation including gender composition and hierarchical status may "shape and define" women's experience on the job. The present study examined the managerial level's gender gap and "glass ceiling" of the corporation. According to Kanter, if the ratio of women to men in organizations begins to shift, as affirmative action and new hiring and promotion policies promised, forms of relationships and corporate culture should also change. However, the mere presence of women on workplace may not, in itself, result in women-friendly work condition. This study analyzes "Korean Women Manger Panel survey(2010 3rd. wave)" to examine how much gender gap of the managerial level persists and when the glass ceiling effect emerges. Using t-test and ANOVA, various aspects of the gender gap within managerial level were verified. The most significant finding is the glass ceiling effect starts from very low level of management. Policy implications from the statistical analysis of the Panel survey are: 1) We need to increase the absolute number of the women managers for securing middle level women leadership pipe line. 2) We need to confront the fact that the glass ceiling starts from the very low managerial level, and to explore more realistic way to break up the vicious circle for the tokenism. and 3) We need to looking beyond numbers in approaching women's matter at work. At the cultural and institutional level, work-family programs and policies, women's ratings of their competence, and family-friendly organization's climate should be considered.

• Journal of Korean Historical Folklife
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• no.26
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• pp.71-106
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• 2008

The objective of this research is to reconstruct an aristocratic officer's travels by analysing Yu, hee-chun's diary, Miamilgi. Yu had kept his diary for eighty three months, from October 1567 to May 1577, and there were twenty six times of travel logs which are analysed in this research. As a result of the analysis, his travels can be divided into official travels and private travels. Sixteen times of official travels were comprised of inspection tours for parishes as a superintendent of Jeonra province, trips to supervise maintenance works of royal tombs and to worship the tombs, to carry out the sanjae (rituals in the mountains) as a second minister of the ministry of rites. It was difficult for him to have private travels as he continually served as a royal officer. He had got only 10 times of private travels during the eighty three months for maintaining the ancestor's tomb and worshiping the ancestors, for recuperating himself and his wife, and for constructing his new house. All of these travels were long-distance ones. In terms of his travel routes, he frequently used royal main trunks, e.g. 'Haenamro' (from Seoul to Damyang), which were maintained by the royal government. The main reason of his frequent using of trunk lines was that convenience facilities such as the royal post stations (Yeok) and royal inns (Won) were equipped well in these roads so it was easy to get horse change services and lodging and boarding. The fact that main trunks were chiefly straight lines and the shortest way was rather secondary reason. On the other hand, when he was a superintendent of Junra province, he had four times of round inspection on all parishes of Junra province, following the tour routs covering all over the province. As he was incumbent royal officer, he started his travel by getting a permission from the king. Simultaneously, he made ready some travel items. Among the items, horse was most important one for the journey. After finishing all the preparing processes before the departure, he had special farewell ceremony for the King, Sookbae, and had a small party with his friends called Jeonbeul. Main transportation means for his travel was horse, and many kinds of horses such as royal government's horse, Yeokma, local government's horse, Swema, as well as his private one were used. Additionally, he used a palanquin while he was doing inspection trip as a superintendent of Junra province. Yu was incumbent officer so he mostly lodged in local government guest houses. If he could not find out any local guest house, he was lodged in royal inn, and in his relatives houses or irregularly in buddhist temples. Most meals were supplied by local royal governments. The activities in his journeys were varied on his travel objectives. In his private journey, it was the main activities that maintaining ancestor's tombs and having a memorial service. During the trip, he visited his relatives. His official trips, on the other hand, had a regularity. Main activities were dealing with public works, and visiting Hyanggyo (country public school). However in the midway, he visited his relatives and had a journey to scenic places.

• Journal of Intelligence and Information Systems
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• v.26 no.4
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• pp.67-86
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• 2020

Recommender Systems have been huge influence users and business more and more. Recently the importance of E-commerce has been reached rapid growth greatly in world-wide COVID-19 pandemic. Recommender system is the center of E-commerce lively. Top ranked E-commerce managers mentioned that recommender systems have a major influence on customer's purchase such as about 50% of Netflix, Amazon sales from their recommender systems. Most algorithms have been focused on improving accuracy of recommender system regardless of novelty, diversity, serendipity etc. Recommender systems with only high accuracy cannot satisfy business long-term profit because of generating sales polarization. In addition, customers do not experience enjoyment of shopping from only focusing accuracy recommender system because customer's preference is changed constantly. Therefore, recommender systems with various values need to be developed for user's high satisfaction. Reranking is the most useful methodology to realize diversity of recommender system. In this paper, diversity of recommender system is represented through constructing high similarity with users who have different preference using each user's purchased item's category algorithm. It is distinguished from past research approach which is changing the algorithm of recommender system without user's diversity preference level. We tried to discover user's diversity preference level and observed the results how the effect was different according to user's diversity preference level. In addition, graph-based recommender system was used to show diversity through user's network, not collaborative filtering. In this paper, Amazon Grocery and Gourmet Food data was used because the low-involvement product, such as habitual product, foods, low-priced goods etc., had high probability to show customer's diversity. First, a bipartite graph with users and items simultaneously is constructed to make graph-based recommender system. However, each users and items unipartite graph also need to be established to show diversity of recommender system. The weight of each unipartite graph has played crucial role changing Jaccard Distance of item's category. We can observe two important results from the user's unipartite network. First, the user's diversity preference level is observed from the network and second, dissimilar users can be discovered in the user's network. Through the research process, diversity of recommender system is presented highly with small accuracy loss and optimalization for higher accuracy is possible controlling diversity ratio. This paper has three important theoretical points. First, this research expands recommender system research for user's satisfaction with various values. Second, the graph-based recommender system is developed newly. Third, the evaluation indicator of diversity is made for diversity. In addition, recommender systems are useful for corporate profit practically and this paper has contribution on business closely. Above all, business long-term profit can be improved using recommender system with diversity and the recommender system can provide right service according to user's diversity level. Lastly, the corporate selling low-involvement products have great effect based on the results.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1449-1463
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• 2020

As recent global warming and climate changes become more serious, the importance of CO2 absorption by forests is increasing to cope with the greenhouse gas issues. According to the UN Framework Convention on Climate Change, it is required to calculate national CO2 absorptions at the local level in a more scientific and rigorous manner. This paper presents the gridded expansion of forest flux observations and mapping of daily CO2 absorption by the forests in Korea using numerical weather prediction data and satellite images. To consider the sensitive daily changes of plant photosynthesis, we built a machine learning model to retrieve the daily RACA (reference amount of CO2 absorption) by referring to the climax forest in Gwangneung and adopted the NIFoS (National Institute of Forest Science) lookup table for the CO2 absorption by forest type and age to produce the daily AACA (actual amount of CO2 absorption) raster data with the spatial variation of the forests in Korea. In the experiment for the 1,095 days between Jan 1, 2013 and Dec 31, 2015, our RACA retrieval model showed high accuracy with a correlation coefficient of 0.948. To achieve the tier 3 daily statistics for AACA, long-term and detailed forest surveying should be combined with the model in the future.