• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.975-984
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• 2018

Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. A 500 g of Quercus mongollica which grounded 0.8~1.4 mm was processed into bio-oil via fast pyrolysis for 2 seconds at $550^{\circ}C$. The esterification consists of treating pyrolysis oil with a high boiling alcohol like n-butanol at $70^{\circ}C$ under reduced pressure (100 hPa). All products are analyzed for water mass fraction, viscosity, higher heating value, pH, FT-IR and GC/MS. The water mass fraction can be reduced by 91.4 % (from 31.5 % to below 2.7 %), the viscosity by 65.8 % (from 36.5 to 12.5 cP) and the higher heating value can be increased by 96.8 % (from 3,918 to 7,712 kcal/kg), the pH by 1.3 (from 2.7 to 4.0). FT-IR and GC/MS analysis indicated that labile acids, aldehydes, ketones and lower alcohols were transformed to stable target products. Using this approach, the water content of the pyrolysis oil is reduced significantly. These improvements should allow the utilization of upgraded pyrolysis liquids in standard boilers and as fuel in CHP (Combined heat and power) plants.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.4
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• pp.479-499
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• 2019

State assessment of an operational tunnel is usually done by performing visual inspection and durability tests by following the detailed guideline for safety inspection (SI) and/ or precision inspection for safety and diagnosis (PISD). In this study, 12 NATM tunnels, which have been operational for more than 10 years, were inspected to figure out the cause of longitudinal cracks for the purpose of modifying the scoring items in the state assessment NATM tunnel related to the longitudinal crack and the thickness of concrete lining. All investigated tunnels were classified into four groups depending on the shape and usage of each tunnel. The causes of longitudinal crack occurrence were analyzed by investigating the correlations between the longitudinal crack and the following four factors: the patterns of ground excavation; construction state of primary support system; characteristics of material properties of the concrete lining; and thickness of lining which was obtained by Ground Penetration Radar (GPR) tests. It was found that influencing factors causing longitudinal cracks in the lining were closely related with the construction condition of the primary support system, i.e. shotcrete, rockbolt, and steel-rib; crack occurrences were not much affected by the excavation patterns. As for the properties of concrete lining materials, occurrence of the longitudinal crack was mostly affected by the following three items: w/c ratio; contents of cement; and strength of lining. When estimating the lining thickness of the concrete lining by GPR tests and taking thickness effect into account in the statement assessment, it was concluded that increase of the index score by an average of 0.03 (ranging from 0.01 up to 0.071) is needed; a more realistic way of state assessment should be proposed in which the increased index score caused by lack of lining thickness should be taken into account.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.62-79
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• 2019

This study examined the background of Gyeongju Seochulji Pond (world heritage, historic site No. 138), a historic pond in Sam-guk-yu-sa (三國遺事), and its landscaping period when it served as the garden of the Pungcheon Lim clan (豊川 任氏) in the middle of the Joseon dynasty. For this study, a literature review of poetry, prose, and a personal anthology, and a field survey were conducted. Changes in the landscape were analyzed by comparing the landscape appearing in the literature of the Joseon period with past photographs. The results were as follows: First, even though the function and landscape at that time cannot be guessed as the objective ground from Silla to the early part of the Joseon dynasty is insufficient, it has been managed as a Byeolseo (別墅) garden as Pungcheon Lim's family resided in the area of Eastern-Namsan Mountain during the Joseon dynasty. At that time, Seochulji Pond was recognized as a historic place. It functioned as the garden of Pungcheon Lim's family as Lim Jeok (任勣, 1612~1672) built the Yiyodang pavilion (二樂堂). Second, in the literature, the Yiyodang pavilion has been called Gaekdang (客堂), Jeongsa (精舍), Byeolgak (別閣) and Byeolseo, etc. It can be seen as Nu and Jeong (樓亭), utilized for various uses. Because of this, the name Bingheoru Pavilion (憑虛樓) has mostly been in common use. Third, Seochulji Pond was positioned where the scenery is beautiful, with Gyeongju Mt. Namsan (Mt. Geumo) in the background and with a wide field and the Namcheon River flowing in the front. This was typical of Byeolseo gardens of the Joseon dynasty, combining human environments with natural environments. Fourth, the relationship with the Byeolseo garden disappeared as the head of Pungcheon Lim's family added a temple, lotus flowers, pine trees, and a bamboo forest as described in the old poetry and prose. Currently, the landscape does not appear to be significantly different from that as development has not occurred in the area of Seochulji Pond. Also, crape myrtle (Lagerstroemia indica), which now symbolizes the Seochulji Pond, was not identified in the old poetry or past photographs and is not old enough to confirm whether it was prominent at the time. Through this study, it is necessary to reconsider the spatial meanings of the gardens of the Joseon dynasty period and not to highlight the area of Seochulji Pond as a place in the legend. This is a cultural asset in the area of Eastern-Namsan Mountain and has an important meaning in terms of garden history.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.127-136
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• 2019

Sweet sorghum (Sorghum bicolor L. Moench), compared to traditional crops, has been evaluated as a useful crop with high adaptability to the environment and various uses, but cultivation has not expanded owing to a lack of related research and information in Korea. This study was conducted to estimate heading date in 'Chorong' sweet sorghum based on climate data of the last 30 years (1989 - 2018) from six regions (Jeonju, Buan, Jeongup, Imsil, Namwon, and Jangsu) in Jellabuk Province. In addition, we compared the growth and quality factors by sowing date (April 10, April 25, May 10, May 25, June 10, June 25, and July 10) in 2018. Days from sowing to heading (DSH) increased to 107, 96, 83, 70, 59, 64, and 65 days in order of the sowing dates, respectively, and the average was 77.7 days. The effective accumulated temperature for heading date was $1,120.3^{\circ}C$. The mean annual temperature was the highest in Jeonju, followed in descending order by Jeongup, Buan, Namwon, Imsil, and Jangsu. The DSH based on effective accumulated temperature gradually decreased in all sowing date treatments in the six regions during the last 30 years. DSH of the six regions showed a negative relationship with mean temperature (sowing date to heading date) and predicted DSH ($R^2=0.9987**$) calculated by mean temperature was explained with a probability of 89% of observed DSH in 2017 and 2018. At harvest, fresh stem weight and soluble solids content were higher in the April and July sowings, but sugar content was higher in the May 10 ($3.4Mg{\cdot}ha^{-1}$) and May 25 ($3.1Mg{\cdot}ha^{-1}$) sowings. Overall, the April and July sowings were of low quality and yield, and there is a risk of frost damage; thus, we found May sowings to be the most effective. Additionally, sowing dates must be considered in terms of proper harvest stage, harvesting target (juice or grain), cultivation altitude, and microclimate.

• Journal of Intelligence and Information Systems
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• v.24 no.4
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• pp.197-217
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• 2018

Music is one of the most creative act that can express human sentiment with sound. Also, since music invoke people's sentiment to get empathized with it easily, it can either encourage or discourage people's sentiment with music what they are listening. Thus, sentiment is the primary factor when it comes to searching or recommending music to people. Regard to the music recommendation system, there are still lack of recommendation systems that are based on customer sentiment. An algorithm's that were used in previous music recommendation systems are mostly user based, for example, user's play history and playlists etc. Based on play history or playlists between multiple users, distance between music were calculated refer to basic information such as genre, singer, beat etc. It can filter out similar music to the users as a recommendation system. However those methodology have limitations like filter bubble. For example, if user listen to rock music only, it would be hard to get hip-hop or R&B music which have similar sentiment as a recommendation. In this study, we have focused on sentiment of music itself, and finally developed methodology of defining new index for music recommendation system. Concretely, we are proposing "SWEMS" index and using this index, we also extracted "Sentiment Pattern" for each music which was used for this research. Using this "SWEMS" index and "Sentiment Pattern", we expect that it can be used for a variety of purposes not only the music recommendation system but also as an algorithm which used for buildup predicting model etc. In this study, we had to develop the music recommendation system based on emotional adjectives which people generally feel when they listening to music. For that reason, it was necessary to collect a large amount of emotional adjectives as we can. Emotional adjectives were collected via previous study which is related to them. Also more emotional adjectives has collected via social metrics and qualitative interview. Finally, we could collect 134 individual adjectives. Through several steps, the collected adjectives were selected as the final 60 adjectives. Based on the final adjectives, music survey has taken as each item to evaluated the sentiment of a song. Surveys were taken by expert panels who like to listen to music. During the survey, all survey questions were based on emotional adjectives, no other information were collected. The music which evaluated from the previous step is divided into popular and unpopular songs, and the most relevant variables were derived from the popularity of music. The derived variables were reclassified through factor analysis and assigned a weight to the adjectives which belongs to the factor. We define the extracted factors as "SWEMS" index, which describes sentiment score of music in numeric value. In this study, we attempted to apply Case Based Reasoning method to implement an algorithm. Compare to other methodology, we used Case Based Reasoning because it shows similar problem solving method as what human do. Using "SWEMS" index of each music, an algorithm will be implemented based on the Euclidean distance to recommend a song similar to the emotion value which given by the factor for each music. Also, using "SWEMS" index, we can also draw "Sentiment Pattern" for each song. In this study, we found that the song which gives a similar emotion shows similar "Sentiment Pattern" each other. Through "Sentiment Pattern", we could also suggest a new group of music, which is different from the previous format of genre. This research would help people to quantify qualitative data. Also the algorithms can be used to quantify the content itself, which would help users to search the similar content more quickly.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.2
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• pp.117-132
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• 2019

The study examines the significance and limits of modern park planning by analyzing major planning documents of Gyeongseong in the Japanese colonial era. Among seven selected documents from 1925 to 1940, which show the contents related with park planning, documents of 1930 and 1940 presented the official park plan of Gyeongseong. By the 1920s, the park plan was not a major concern in urban planning of Gyeongseong; however, as the planning law as enacted in 1934, the park plan legally became a part of the official master planning process in the 1930s. In 1940, the most comprehensive park plan for Gyeongseong was published. In the beginning of modern urban planning, a park was mainly perceived as a sanitation utility. From the 1920s to the 1930s, the park planning system was significantly improved including systemic classification of parks, guideline development considering spatial planning, and introduction of a concept of infra-structural green space. Despite of the improvement in the park planning, the actual quantity of the overall green spaces barely changed and there was a huge discrepancy between the planning ideal and the reality. The Gyeongseong stadium was the only facility newly built in the 1920s, and only two parks were constructed in the 1930s. The plan to build 38 new parks in the 1930, and 140 in the 1940 was barely realized. However, there were efforts to improve parks and green spaces of Gyeongseong: Such as appropriating natural forest as parks, designating royal palaces as parks, and focusing on constructing smaller scale children's parks. Even though the ideal plan could not be fully implemented due to the war time situation and tight budget, the park system of Gyeongseong provided the framework of park planning of Seoul after the independence.

• Journal of Life Science
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• v.28 no.11
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• pp.1339-1346
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• 2018

In Korea, edible mushrooms are produced largely on commercial artificial media, so the annual production of spent mushroom substrate (SMS), as a by-product of the mushroom industry, is estimated at over 200 million tons. This SMS is assumed to contain abundant fungal mycelia and pre-fruiting bodies, as well as various nutritive and bioactive compounds that are presently discarded. This study examined the physico-chemical, nutritional, and enzymatic characteristics of uninoculated sterilized medium (USM) and SMS of shiitake mushrooms with the aim of developing a high-value added product from SMS. The contents of crude protein, crude lipid, and ash were higher after the third SMS harvest ($SMS-A-3^{rd}$) than in USM or $SMS-A-1^{st}$. The contents of Ca, Mg, and P in $SMS-A-3^{rd}$ were 2.95, 2.35, and 2.1-fold higher compared than in USM. No As or Cd was detected in USM or SMS. The pH, Brix, and acidity were 4.6, 20.0, and 1.4, respectively in $SMS-A-3^{rd}$, but 5.6, 6.0, and 0.0, respectively, in USM. These results suggest a highly active production of soluble components and organic acids in $SMS-A-3^{rd}$. The distinct color differences noted for USM, $SMS-A-1^{st}$, and $SMS-A-3^{rd}$ could be used as a mycelial growth indicator. Enzyme activity assays using the APIZYM system showed that SMS is a potent source of hydrolysis-related enzymes, especially esterase (C4) and ${\beta}$-glucuronidase. Our results suggested that the SMS of shiitake has a high potential for use in environmental, agricultural, and stock-breeding industries, for example, as active ingredients for sewage treatment, waste-polymer degradation, and feed additives.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.167-174
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• 2019

A process-oriented crop growth model can simulate the biophysical process of rice under diverse environmental and management conditions, which would make it more versatile than an empirical crop model. In the present study, we examined chronology and background of the development of the rice growth models in Korea, which would provide insights on the needs for improvement of the models. The rice crop growth models were introduced in Korea in the late 80s. Until 2000s, these crop models have been used to simulate the yield in a specific area in Korea. Since then, improvement of crop growth models has been made to take into account biological characteristics of rice growth and development in more detail. Still, the use of the crop growth models has been limited to the assessment of climate change impact on crop production. Efforts have been made to apply the crop growth model, e.g., the CERES-Rice model, to develop decision support system for crop management at a farm level. However, the decision support system based on a crop growth model was attractive to a small number of stakeholders most likely due to scarcity of on-site weather data and reliable parameter sets for cultivars grown in Korea. The wide use of the crop growth models would be facilitated by approaches to extend spatial availability of reliable weather data, which could be either measured on-site or estimates using spatial interpolation. New approaches for calibration of cultivar parameters for new cultivars would also help lower hurdles to crop growth models.

• Korean Journal of Labor Studies
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• v.23 no.1
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• pp.47-83
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• 2017

The Swedish labor market secures flexibility in the use of labor force by means of non-regular workers such as temporary workers among others instead of regular workers' layoffs. Although the labor law reform in the late 2000s made it easier to use temporary workers and the outbreak of the economic crisis strengthened the power of user firms against labor unions, the size of temporary workers was scaled down. It is the aim of this study to analyze the change in the use of temporary workers, to examine the effect of the labor law reform and that of economic crisis in that regard, and to explain how, over the use of temporary workers, user firms' strategy to secure flexibility and labor unions' strategy to regulate flexibility interact with each other so as to establish a new equilibrium through conflicts and compromises. The labor law reform to enhance the flexibility in the use of temporary workers failed to entail amendments of collective contracts. Besides, out of the economic crisis, user firms adopted a new policy to use third party workers more, refraining from employing temporary workers. That's why the number of temporary workers has declined eventually. User firms prefer to use third party workers because they could avoid their own responsibility as an employer and they could rely on 'permanent temporary' workers without any time limit. Labor unions, however, responded with a strategy to lay more strict regulations on the use of third party workers, so that third party workers could be used only for limited cause for external numerical flexibility. As a result, the managed flexibility thesis comes to prevail to the usage of non-regular workers in general beyond the category of agency workers. Korea with severe abuse of third party workers should learn from Swedish labor unions' strategy to provide third party workers with stronger employment security and higher wages so as to prevent user firms from abusing third party workers.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.281-304
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• 2022

Heungdeokjeon was the first pavilion built on the site of Sueocheong during the expansion of Gyeongungung. In this study, we tried to clarify the specific construction process of Heungdeokjeon, which was used for various purposes such as the copy location for Portraits of ancestors, temporary enshrinement site, and the funeral building for the rest of the body, which is Binjeon. In addition, we tried to confirm the historical value based on the characteristics derived by the history of the building and the rituals performed. Heungdeokjeon began to be built in the second half of 1899, and is estimated to have been completed between mid-February and mid-March 1900. It was a ritual facility equipped with waiting rooms for the emperor and royal ladies as an annex. The relocation work was planned in April 1901 and began in earnest after June, and it was closely linked to the construction of attached buildings of Seonwonjeon. In addition, comparing the records on the construction and relocation cost of Heungdeokjeon with those related to the reconstruction of Seonwonjeon, it was confirmed that annex buildings of Heungdeokjeon were relocated and used as annex buildings of Seonwonjeon. The characteristics identified in the process of Heungdeokjeon used as a place to copy portraits are as follows. First, it was used as a place to copy portraits twice in a short period of time. Second, it was the place where the first unprecedented works were carried out in relation to the copying of portraits. Third, the pavilion, which was specially built for imperial rituals, was used as a place to copy portraits. Since then, it has been used as a funeral building for the rest of the body, and features different from those of the previous period are identified. It was the building dedicated to rituals for use as Binjeon, and was also a multipurpose building for copying portraits. In other words, Heungdeokjeon, along with Gyeongbokgung Taewonjeon, is the building that shows the changes in the operation of Binjeon in the late Joseon Dynasty. Characteristics are also confirmed in portrait-related rituals performed at Heungdeokjeon. The first is that Jakheonlye was practiced frequently in a short period of time. The second is that the ancestral rites of Sokjeolje and Bunhyang in Sakmangil, which are mainly held in the provincial Jinjeon, were identified. This is a very rare case in Jinjeon of the palace. The last is that Jeonbae, jeonal, and Bongsim were implemented mutiple times. In conclusion, Heungdeokjeon can be said to be a very symbolic building that shows the intention of Gojong, who valued imperial rituals, and the characteristics of the reconstruction process of Gyeongungung.