• 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.

• (The)Study of the Eastern Classic
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• no.73
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• pp.153-184
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• 2018

The aim of this thesis was to examine the circumstances that led up to successful coin use across the entire nation in 1678 (the $4^{th}$ year of King Sukjong's reign), during the Joseon Dynasty. To this end, this thesis analysed the Sa-Mouk(事目, Provisions) that contained the institutional protocol for coin circulation, implemented by King Hyojong and the statesman Kim Youk(金堉) who had practical experience in these matters over the ten years of King Hyojong's reign(1649-1659). To regulate the problematic wide circulation of coarse cotton cloth as currency in the market of 1650 (the $1^{st}$ year of King Hyojong's reign), prohibition measures were implemented. Besides the superficial justification given for these measures(i.e., that the market price was disturbed by the use of coarse cotton cloth), there was another purpose to prohibiting the circulation of cotton cloth as money, following the standard ruled by the government: the state aimed to ensure momentum for the upcoming coin circulation policy, by strengthening its control of the current economy. In 1651 (the $2^{nd}$ year of King Hyojong's reign), the government fully cracked down on the use of coarse cotton cloth as currency, and simultaneously implemented its coin circulation policy in the Pyeongan(平安) region. The pretext for this policy was to raise finances to support people who were starving as a result of poor harvests and famine. People who received coins from government officials could purchase food in the market, and the coin circulation policy was judged to be successful. Subsequently, to extend coin circulation further throughout the region, the Sa-Mouk for Seoul was established. The Sa-Mouk included stipulations regarding the use of coin in transactions and for government expenditure; it aimed thereby to enhance the national policy's market credit. The hasty implementation of the policy for the expansion of coin circulation caused some problems that required its modification. In 1652 (the $3^{rd}$ year of King Hyojong's reign), coin circulation was increased to encompass the Gyeonggi(京畿) region, and some of the tax that had been paid in rice was now paid in coin. However, coins were in short supply, since there was insufficient copper, the main material used in coin production, and the policy faced a significant limitation. Therefore, in 1655(the $6^{th}$ year of King Hyojong's reign), a new Sa-Mouk for coin circulation was established. This Sa-Mouk included specifications regarding the determination of coin values based on rice and silver, and mandated the wide spread installation of stores for exchanging spot goods for coins throughout the region in which coins were circulating. This policy's objective was to secure stability for the national economy by further regulating coin circulation. The sustained implementation of the coin circulation policy for ten years by King Hyojong and the statesman Kim Youk offered the government an opportunity to accumulate experience in coin circulation in the market, and also to learn from institutional trial and error. This may have been one of the contributing factors to the nation-wide coin circulation that was established in 1678. The objective of the policy implemented during King Hyojong's reign was not to meet the market's requirements, but rather to ensure the preservation of the national economy, and this misjudgement constituted the policy's key limitation. At this time, the government urgently needed to secure finances to cope with the war against China's Qing Dynasty.

• 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.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.1-10
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• 2020

Reactivity controlled compression ignition (RCCI) combustion is one of dual-fuel combustion systems which can be constructed by early diesel injection during the compression stroke to improve premixing between diesel and air. As a result, RCCI combustion promises low nitrogen oxides (NOx) and smoke emissions comparing to those of general dual-fuel combustion. For this combustion system, to meet the intensified emission regulations without emission after-treatment systems, exhaust gas recirculation (EGR) is necessary to reduce combustion temperature with lean premixed mixture condition. However, since EGR is supplied from the front of turbocharger system, intake pressure and the amount of fresh air supplementation are decreased as increasing EGR rate. For this reason, the effect of various EGR rates on the brake power and thermal efficiency of natural gas/diesel RCCI combustion under two different operating conditions in a 6 L compression ignition engine. Varying EGR rate would influence on the combustion characteristic and boosting condition simultaneously. For the 1,200/29 kW and 1,800 rpm/(lower than) 90 kW conditions, NOx and smoke emissions were controlled lower than the emission regulation of 'Tier-4 final' and the maximum in-cylinder pressure was 160 bar for the indurance of engine system. The results showed that under 1,200 rpm/29 kW condition, there were no changes in brake power and thermal efficiency. On the other hand, under 1,800 rpm condition, brake power and thermal efficieny were decreased from 90 to 65 kW and from 37 to 33 % respectively, because of deceasing intake pressure (from 2.3 to 1.8 bar). Therefore, it is better to supply EGR from the rear of compressor, i.e. low pressure EGR (LP-EGR) system, comparing to high pressure EGR (HP-EGR) for the improvement of RCCI power and thermal efficiency.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.188-197
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• 2020

Termites play an important role as decomposers of the forest ecosystem, while simultaneously causing enormous damage to wooden structures. Currently, two species of subterranean termites have been reported in Korea, and termite damage to historical wooden buildings is occurring nationwide due to climate change, forest fertility, and the locational characteristics of historical wooden buildings. Subterranean termites make their nests underground or inside timber. Termites move underground and access wooden structures through the lower parts of the buildings, adjacent to the ground. Once termites attack the wooden structures, it not only spoils the authenticity of cultural heritage structure, but also hampers structural stability due to the decrease in the strength of the material. Therefore, it is important to prevent termite damage before it occurs. Chemical treatments are mainly used in Korea to control and prevent the damage. In foreign countries, physical barriers are also used to prevent entry to wooden buildings, along with chemical treatments. Physical barriers involve installing nets or particles that termites cannot pass through in the lower part of the building, around the pipes, and between the edges of the building or exterior walls and interior materials. Advantages of a physical barrier are that it is an eco-friendly method, maintains long-term effect after installation, and does not require the use of chemical treatments. Prior to applying physical barriers, studies into the characteristics of termite species must be undertaken. In this study, we evaluated the minimum passage size that each caste of Reticulitermes speratus kyushuensis can move through. We found that workers, soldiers, and secondary reproductive termites were able to pass through diameters of 0.7mm, 0.9mm, and 1.1mm respectively. Head height of termites was an important factor in determining the minimum passing size. Results from the current study will be used as a basis to design the mesh size for physical barriers to prevent damage by termites in historical wooden buildings in Korea.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.31-39
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• 2021

We aimed to investigate the age-dependent development of digestive organs, intestinal enzymes, and hepatic antioxidant defense system in White Leghorn chicks aged 0, 3, 7, 14, and 21 days. Body weight (BW) did not significantly change between days 0 and 7 but significantly increased (P<0.05) after day 7. The relative liver weight (g/100 g of BW) was significantly lower at day 0 than at the other ages but markedly increased at days 3 and 7 (P<0.05). The relative pancreatic weight changed similar to the change in liver weight, with the maximum development at 7 days (P<0.05). The relative intestinal and mucosal tissue weights increased rapidly after hatching (P<0.05), with the maximum growth at 7 days. Furthermore, maltase and sucrase activities were significantly higher at day 3 than at day 0 (P<0.05). Leucine aminopeptidase activity was high at day 0 and remained constant as age increased. Superoxide dismutase and glutathione S-transferase activities in the liver were the lowest at day 0 but significantly increased after 7 days (P<0.05). Glutathione peroxidase activity increased significantly after day 14 compared with that at days 0 and 7 (P<0.05). Lipid peroxidation was not affected by age. In conclusion, the digestive organ weights and hydrolase activity of chicks increased rapidly during the first 3 or 7 days post-hatching. Hepatic antioxidant enzyme activity increased simultaneously with the increase in digestive organ weights, after 7 days.

• Ecology and Resilient Infrastructure
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• v.8 no.1
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• pp.32-43
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• 2021

Multichannel automated chamber systems (MCACs) were developed for the continuous monitoring of soil CO2 efflux in forest ecosystems. The MCACs mainly consisted of four modules: eight soil chambers with lids that automatically open and close, an infrared CO2 analyzer equipped with eight multichannel gas samplers, an electronic controller with time-relay circuits, and a programmable logic datalogger. To examine the stability and reliability of the developed MCACs in the field during all seasons with a high temporal resolution, as well as the effects of temperature and soil water content on soil CO2 efflux rates, we continuously measured the soil CO2 efflux rates and micrometeorological factors at the Nam-san experimental site in a Quercus mongolica forest floor using the MCACs from January to December 2010. The diurnal and seasonal variations in soil CO2 efflux rates markedly followed the patterns of changes in temperature factors. During the entire experimental period, the soil CO2 efflux rates were strongly correlated with the temperature at a soil depth of 5 cm (r2 = 0.92) but were weakly correlated with the soil water content (r2 = 0.27). The annual sensitivity of soil CO2 efflux to temperature (Q10) in this forest ranged from 2.23 to 3.0, which was in agreement with other studies on temperate deciduous forests. The annual mean soil CO2 efflux measured by the MCACs was approximately 11.1 g CO2 m-2 day-1. These results indicate that the MCACs can be used for the continuous long-term measurements of soil CO2 efflux in the field and for simultaneously determining the impacts of micrometeorological factors.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.150-162
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• 2021

Companies have recently become increasingly interested in corporate entrepreneurship to establish a core employment policy in order to secure and maintain core employees and to foster an innovation-oriented organizational culture. Therefore, The purpose of this study is to empirically analyze the causal relationship between core employment policies and the team leader's the perceived internal process organizational competency and job satisfaction, and to investigate whether corporate entrepreneurship has a moderation effect. Non-financial service industries including ICT companies were subject of the study and human capital corporate panel(HCCP) was utilized. The samples were 367 team leaders from 79 domestic companies. This study also applied Multi-Level Analysis(HLM), which simultaneously analyzes variables at both the individual level and the organizational level in order to improve the accuracy of the study. According to the result of the study analysis, core employment policies have a positive(+) impact on the perceived internal process organizational competency and job satisfaction. In addition, the moderation effect of corporate entrepreneurship was verified during the process when core employment policies influence the two outcome variables. corporate entrepreneurship was found to have a moderation effect that strengthens the influence on job satisfaction, but the moderation effect on the perceived internal process organizational competency was not statistically significant. These results confirm that organizational cultural factors such as corporate entrepreneurship are important influence variables in the process of influencing individual-level variables such as core employment policies. Academically, It suggests that in order to enhance the effectiveness of company strategies in respect of human resource management such as core employment policies, it is important to foster a cultural environment that suits the industry and characteristics of the organization. In addition, it suggested that companies in need of new innovation need to utilize corporate entrepreneurship.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.1
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• pp.109-130
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• 2022

The Vietnamese government has proposed contract farming through a new type of cooperative as an institutional innovation which aims to restructure the agricultural sector. However, policy changes often impact farmers, who bear the primary effects of the transition process. Understanding households' strategies for land use and livelihood is crucial for policymaking in the agricultural development field. This study was conducted in the rural Binh Dao commune in Central Vietnam. We analyzed household members' labor force changes and their livelihood behaviors after their participation in a contract farming scheme using qualitative analysis methods combined with geographic information system (GIS) support, based on secondary data and in-depth interviews of 190 farmers. Simultaneously, we created a digital map of the cooperative's production area to investigate changes in land use and production activities. The findings show that contract farming shaped the vertical coordination of the value chain from the farmers to the cooperative and agricultural product trading companies. Subsequently, it encouraged land use and labor efficiency due to mechanical support. In addition, it also increased productivity and protected farmers from market risks. However, despite its positive effects on agricultural productivity in this case, the contract farming scheme could not achieve the restructuring of the rural labor force toward non-agricultural sectors. Ironically, farmers in the Binh Dao commune tended to increase cultivable land during the agricultural restructuring program, rather than switching their labor forces to non-agricultural sectors. The lack of stable non-farming job opportunities in rural Vietnam results in challenges to the efficiency of agricultural restructuring programs. Consequently, farmers in the Binh Dao commune are still smallholder farmers, depending on the family labor force.

• Journal of Korean Society of Disaster and Security
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• v.15 no.1
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• pp.1-12
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• 2022

An automatic optimization technique is used to estimate the optimal parameters of the hydrologic model, and different hydrologic response results can be provided depending on objective functions. In this study, the parameters of the event-based rainfall-runoff model were estimated using various objective functions, the reproducibility of the hydrograph according to the objective functions was evaluated, and appropriate objective functions were proposed. As the rainfall-runoff model, the storage function model(SFM), which is a lumped hydrologic model used for runoff simulation in the current Korean flood forecasting system, was selected. In order to evaluate the reproducibility of the hydrograph for each objective function, 9 rainfall events were selected for the Cheoncheon basin, which is the upstream basin of Yongdam Dam, and widely-used 7 objective functions were selected for parameter estimation of the SFM for each rainfall event. Then, the reproducibility of the simulated hydrograph using the optimal parameter sets based on the different objective functions was analyzed. As a result, RMSE, NSE, and RSR, which include the error square term in the objective function, showed the highest accuracy for all rainfall events except for Event 7. In addition, in the case of PBIAS and VE, which include an error term compared to the observed flow, it also showed relatively stable reproducibility of the hydrograph. However, in the case of MIA, which adjusts parameters sensitive to high flow and low flow simultaneously, the hydrograph reproducibility performance was found to be very low.