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Syntheses of 70% Solids Acrylic Resin and Comparative Study in Physical Properties as Acrylic Urethane Resin Coatings (고형분 70% 아크릴수지 합성과 아크릴-우레탄 도료의 도막물성 비교 연구)

  • Kim, Seong-Kil;Park, Hyong-Jin
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.2
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    • pp.476-487
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    • 2021
  • To prepare acrylic resin coatings containing 70% of solids, we used n-butyl methacrylate(BMA), methyl methacrylate(MMA), 2-hydroxyethyl methacrylate(2-HEMA), and acetoacetoxyethyl acrylate(AAEA), caprolactone acrylate(CLA) as raw materials, the glass transition temperature(Tg) of acrylic copolymer was adjusted around 50 ℃. The viscosity and molecular weight of the acrylic resins was increased with increasing OH values. Di-tert-amyl peroxide was found to be the suitable initiator to get high-solids acrylic resins. The optimum reaction conditions found in the study are 5 wt% of initiator, 4 wt% of chain transfer agent, 4 hrs of dropping time, and 140 ℃ of reaction temperature. The structure of the synthesized resins were characterized by FT-IR and 1H-NMR spectroscopy. Number average molecular weight of 1900~2600 and molecular wight distribution of 1.4~2.1 were obtained. Crosslinked acrylic urethane clear coatings were obtained by curing reaction between the synthesized acrylic resins and hexamethylene diisocyanate trimer(Desmodur N-3300), the equivalent ratio of NCO/OH was 1.2/1.0. The physical properties from the following studies were carried out: viscosity(Zahn cup #2), adhesion, drying time, pot-life, pensil hardness, and 60° specular gloss. Various properties of the acrylic urethane clear coatings were also evaluated on the coating specimens. Adhesion property to a substrate, drying time, pot-life, pencil hardness, and 60° specular gloss of prepared paint showed quite good properties. Futhermore, prepared paint containing 10% of CLA showed quite good properties for adhesion, low viscosity and high hardness.

The Violence of Neoliberalism Represented in the Works of Eduardo Galeano (에두아르도 갈레아노의 작품에 나타난 신자유주의의 폭력성)

  • Yoo, Wang-Moo
    • Cross-Cultural Studies
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    • v.41
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    • pp.199-227
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    • 2015
  • In the twenty-first century, one of the most controversial issues concerns neoliberal policies and its results. In particular, since the mid-1980s, the United States and international financial institutions have imposed their programs on Latin American countries. The result is a deepening social inequality in Latin America that puts an emphasis on financial stability instead of social security. Consequently, social inequality is worsened and an imbalance in income distribution took place. Because of the flexibility of labor, the middle class is destroyed. For the poor person deprived of the opportunity to rise, violence is a common occurrence in daily life. Thus, in this context, Eduardo Galeano raises the necessity of a critique concerning the values that neoliberalism regards as important. Furthermore, Galeano is also wary of the "militarization of neoliberalism." This is because the neoliberal multinationals motivate a war without borders under the guise of peace. Neo-liberal policies also contribute to environmental pollution. However, environmental vandalism, which happens in partnership with large and international organizations, is not readily apparent to the public because those perpetrators wore a "green mask." Hence, Galeano assiduously endeavors to undercover the false consciousness hiding behind the green mask. Thus, in brief summary, Galeano represents in his works a depiction about Latin America where violence often happens in daily life.

Comparison of Perceptions on 'Postwar' Between the History of Korean Literature and the History of Japanese Literature ('전후'에 대한 한일문학사 인식 비교 - 한국전쟁을 둘러싼 상반된 해석과 담론 -)

  • Cho, Jung-min
    • Cross-Cultural Studies
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    • v.52
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    • pp.223-251
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    • 2018
  • This paper comparatively considered how Korea and Japan address the concept of 'postwar' in descriptions of their literary history. In Japan, 'postwar' refers to the period after World War II (Asia-Pacific War). This word implies a variety of contexts such as collapse, poverty, confusion, calendar reform, reconstruction and restoration as well as a series of historical events such as war, war defeat, and American occupation; and so it has been treated in Japanese society a significant period. In the history of Korean literature, it is after national liberation that the word 'postwar' appeared; however, it has usually indicated 'the period after the Korean War.' The question is that although the term of postwar refers to periods after different wars, Koreans used the term of postwar also in the same way as Japan, and their concept of postwar overlaps with the concept of prewar or postwar used in Japan, and accordingly, side effects are produced that fail to grasp properly the independent characteristics and significance of the Korean War. In conclusion, the Korean War brought about contrasting effects on the history of Korean and Japanese literature. While the Korean War meant a start after the war in Korean literature, it became a turning point marking the end of postwar in Japanese literature. Such different perceptions on postwar also have major implications in that perceptions represent postwar discourses in today's Korea and Japan.

The Economic Analysis of Underground Parking Lot Frames adopting 8-Bay Parking Modules (8-Bay 주차모듈을 적용한 아파트 지하주차장 구조의 경제성 분석)

  • Yu, Yongsin;Yoon, Bohyung;Kim, Minsu;Kim, Taewan;Lee, Chansik
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.1
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    • pp.52-61
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    • 2019
  • On 30 June, 2017, the Ministry of Land, Infrastructure, and Transport announced the minimum size of parking section will be expanded in parking lots. The expansion of parking section could lead to increase in apartment prices because of increase in total area of the parking lots. It is necessary to adjust the column spacing and number in the parking lots and to apply the 8-Bay long-span parking module with good parking efficiency. According to the study, the construction cost of the 6-Bay module and 8-Bay module was almost the same. But The 8-Bay module was more economical than the 6-Bay module because of the reduction in total area of 8-Bay multi-moduel. The Result of construction cost of 8-Bay modules, Removal Deck-plate RC system was most economical. While the construction cost of PC system was higher due to increase in volume of the member, it would ensure sufficient economy by reducing the girder height to apply a pre-stress method. Also, the construction cost of hollow slab system was the highest. But it could be used as the underground parking lots for apartment, because it had the lowest cost per square meter. This Study has a academic significance by proving the applicability of the 8-Bay Module to underground parking lot of apartment. And it is expected that this study will be used as basic data to derive optimal construction method that applies 8-Bay Module.

Trends and Implication of International Discussion on Forest Sector: Focusing on United Nations Forum on Forests (산림부문 관련 국제적 논의 동향과 시사점: 유엔산림포럼을 중심으로)

  • Choi, Eunho;Kim, Raehyun;Kim, Myungkil
    • Journal of Korean Society of Forest Science
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    • v.107 no.4
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    • pp.325-335
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    • 2018
  • In accordance with the appearance of global issue called Sustainable Development Goals (SDGs), United Nations Forum on Forests (UNFF) has shown a significant progress in such as emphasizing the potential contribution of forest sector and establishing long-term strategies. In relation to the SDGs which would be discussed mainly in different international agreements and conferences related to forest sector until 2030, this study reviewed the discussion trend by establishing integrated databases and focusing on UNFF which serves as an integrated coordinator. It also aims to identify the meaning of United Nations Strategic Plan for Forest (UNSPF) established by UNFF. Furthermore, the following proposals on policies are presented in this study aiming for active discussion on forest sector not only in international but also in national context, and to implement UNSPF and GFGs effectively in a long-term manner: (1) Cooperation among sectors, organizations, and countries is more important than anything to make an active discussion on forest sector; (2) Recognizing and understanding the role and contributions of forests should be encouraged in actual field, and it should serve as the basis when establishing national policies and goals; (3) By fully utilizing UNFF report which is for the review of UNSPF implementation, a rational reporting system should be provided, and simultaneously, the efficiency on reporting items in the process of implementation should be improved.

A Research on the Use of Faceted Navigation of KOLIS-NET (KOLIS-NET의 패싯 네비게이션 활용에 관한 연구)

  • Yoon, Cheong-Ok
    • Journal of the Korean Society for Library and Information Science
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    • v.53 no.1
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    • pp.109-132
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    • 2019
  • The purpose of this study is to examine and propose to improve the features of a simple keyword search box and faceted navigations of KOLIS-NET operated by the National Library of Korea. A record group of '2011-2020 (776)' under 'Publication date' facet, out of 3,702 records retrieved from a search of '김훈', were examined. Major findings are as follows: (1) Five facets including 'Format', 'Publication date', 'Subject', 'Language' and 'Country' are used to limit search results only in the first step, and multiple facets cannot be simultaneously used; (2) With 'Publication date' facet formed in the span of ten years, a separate publication year cannot be identified; (3) 'Subject' facet based on KDC limits the results only in broad subject classes without sub-facets; (4) Under 'Format' facet, a special format such as large print texts cannot be identified; (5) Without 'Author' facet, authors cannot be identified; and (6) 'Publication date missing', 'Language missing', and 'Miscellaneous subject' record groups cannot be clicked and displayed, a navigation to-and-fro between a brief list and bibliographic records is not smooth, etc. Therefore an application of multiple facets in all stages of limiting the search result, a construction of sub-facets for 'Publication date' and 'Subject' facets, an accurate description and coding of 'General Material Designation', etc. are suggested to improve KOLIS-NET's faceted navigation.

Suggestion of Zoning Criteria Based on the Assessment System for River Environment (하천환경 평가체계의 구축에 따른 지구 지정 기준의 검토 및 제안)

  • Chun, Seung-Hoon
    • Journal of Environmental Impact Assessment
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    • v.27 no.6
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    • pp.647-657
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    • 2018
  • This study was carried out to review as criteria for zoning at management plan for river restoration, in case of naturalness of river environment and suitability of water friendly activity suggested at assessment system of river environment in Korea. As a result of reviewing law and guidelines concerned, historic & cultural resources used as criteria for preservation zone, it was judged that the historical and cultural value as the preservation zone needs to be examined in connection with waterfriendly activity zone. In this study, we propose a sequential evaluation method to distinguish the waterfriendly activity zone by applying suitability of waterfriendly activity reflecting land use social characteristics, followed division of preservation and restoration zone at the first stage by the naturalness of river environment reflecting the natural environmental characteristics as a result of application to the test bed, Gap and Yudeung streams. In particular, it was concluded that the results of the present study provided more clear criteria for the problem that the last criteria for zoning did not reflect the difference between the left and the right side of stream, or the designation of the excessive water friendly zone. On the other hand, the criteria for designation in this study reflect the characteristics of various river environments as well as the setting of assessment unit based on the physical characteristics of rivers, and other legal regulations and local situations should be adjusted and supplemented in administrative procedures.

The French Evolution of Protection-Management Systems for Historic Monuments and Their Surroundings over One-Hundred Years: 1913-2016 (프랑스 역사기념물과 그 주변 보호·관리제도의 진화: 1913~2016)

  • Lee, Sujin;Ryu, Je-hun
    • Korean Journal of Heritage: History & Science
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    • v.52 no.3
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    • pp.94-111
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    • 2019
  • This study aims to examine the evolutionary process of the protection-management system for historic monuments and their surroundings in France over one-hundred years. Because France and Korea shared policies and institutions regarding the management of historical monuments (cultural property) along with their surroundings, it is necessary to explore the French experience from a comparative perspective. In France, historical monuments began to be recognized as national heritage according to "the 1913 law" which has continued to evolve for more than one hundred years. In the beginning, a historical monument was preserved as a single building unit; however, since 1943, a new policy has been implemented to preserve sets of historical monuments along with their perimeters of protection zones. Moreover, since 1980, in the context of decentralization, local authorities have been given more roles and autonomy concerning the management of historic monuments and their surroundings. Local authorities have played a key role in the protection-management of historic monuments and their surroundings, and have become more active in the conservation of their architectural heritage, including historic monuments. The central government, however, remains as the headquarters whose rigorous policies provide a solid foundation for the decentralized management system of architectural and cultural heritage, including historic monuments. The final goal in the evolutionary process, then, targets the effective and harmonious integration of the protection-management system for historic monuments and their surroundings into urban and regional planning.

Korean speech recognition using deep learning (딥러닝 모형을 사용한 한국어 음성인식)

  • Lee, Suji;Han, Seokjin;Park, Sewon;Lee, Kyeongwon;Lee, Jaeyong
    • The Korean Journal of Applied Statistics
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    • v.32 no.2
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    • pp.213-227
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    • 2019
  • In this paper, we propose an end-to-end deep learning model combining Bayesian neural network with Korean speech recognition. In the past, Korean speech recognition was a complicated task due to the excessive parameters of many intermediate steps and needs for Korean expertise knowledge. Fortunately, Korean speech recognition becomes manageable with the aid of recent breakthroughs in "End-to-end" model. The end-to-end model decodes mel-frequency cepstral coefficients directly as text without any intermediate processes. Especially, Connectionist Temporal Classification loss and Attention based model are a kind of the end-to-end. In addition, we combine Bayesian neural network to implement the end-to-end model and obtain Monte Carlo estimates. Finally, we carry out our experiments on the "WorimalSam" online dictionary dataset. We obtain 4.58% Word Error Rate showing improved results compared to Google and Naver API.

The Impact of Industry-level Competition on the Excess Stock Returns due to Changes in Cash Holdings (산업 내 경쟁정도가 보유현금의 변화에 따른 초과수익률에 미치는 영향)

  • Cho, Jung Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.163-169
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    • 2019
  • This study examined whether industry-level competition affects excess stock returns because of changes in cash holdings. Competitive inter-company threats increase the possibility of the manager's replacement, and function to induce management to make their best efforts, resulting in the amount and quality of the information provided by the enterprise increasing. Therefore, as competition intensifies, agency problems are reduced and stock returns increase because the company's cash holdings are expected to increase. However, there is a view that firms in industries with severe competition tend to have high information asymmetry because competitors may compete in more favorable positions by using detailed information disclosed by the competing firms. Accordingly, as market competition intensifies, the excess stock returns resulting from increased cash holdings are expected to decline. These results show that excess stock returns because of increases in cash holdings increase as the degree of competition in the industry intensifies, thus supporting the positive effect of market competition. Overall, the results of this study provide an understanding that market competition plays an effective external governance mechanism and that investors positively evaluate the cash held by companies with severe industry competition.