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Adsorption Characteristics of Nitrogen in Carbonaceous Micropore Structures with Local Molecular Orientation (국부분자배향의 탄소 미세기공 구조에 대한 질소의 흡착 특성)

  • Seo, Yang Gon
    • Clean Technology
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    • v.28 no.3
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    • pp.249-257
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    • 2022
  • The adsorption equilibria of nitrogen on a region of nanoporous carbonaceous adsorbent with local molecular orientation (LMO) were calculated by grand canonical Monte Carlo simulation at 77.16 K. Regions of LMO of identical size were arranged on a regular lattice with uniform spacing. Microporosity was predominately introduced to the model by removing successive out-of-plane domains from the regions of LMO and tilting pores were generated by tilting the basic structure units. This pore structure is a more realistic model than slit-shaped pores for studying adsorption in nanoporous carbon adsorbents. Their porosities, surface areas, and pore size distributions according to constrained nonlinear optimization were also reported. The adsorption in slit shaped pores was also reported for reference. In the slit shaped pores, a clear hysteresis loop was observed in pores of greater than 5 times the nitrogen molecule size, and in capillary condensation and reverse condensation, evaporation occurred immediately at one pressure. In the LMO pore model, three series of local condensations at the basal slip plane, armchair slip plane and interconnected channel were observed during adsorption at pore sizes greater than about 6 times the nitrogen molecular size. In the hysteresis loop, on the other hand, evaporation occurred at one or two pressures during desorption.

Adults' perception of mathematics: A narrative analysis of their experiences in and out of school (수학에 대한 성인들의 인식: 학교 안팎에서의 수학적 경험에 대한 내러티브 탐구)

  • Cho, Eun Young;Kim, Rae Young
    • The Mathematical Education
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    • v.61 no.3
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    • pp.477-497
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    • 2022
  • The rapidly changing world calls for reform in mathematics education from lifelong learning perspectives. This study examines adults' perception of mathematics by reflecting on their experiences of mathematics in and out of school in order to understand what the current needs of adults are. With the two questions: "what experiences do participants have during their learning of mathematics in schools?" and "how do they perceive mathematics in their current life?", we analyzed the semi-structured interviews with 10 adults who have different sociocultural backgrounds using narrative inquiry methodology. As a result, participants tended to accept school mathematics as simply a technique for solving computational problems, and when they had not known the usefulness of mathematical knowledge, they experienced frustration with mathematics in the process of learning mathematics. After formal education, participants recognized mathematics as the basic computation skill inherent in everyday life, the furniture of their mind, and the ability to efficiently express, think, and judge various situations and solve problems. Results show that adults internalized school education to clearly understand the role of mathematics in their lives, and they were using mathematics efficiently in their lives. Accordingly, there was a need to see school education and adult education on a continuum, and the need to conceptualize the mathematical abilities required for adults as mathematical literacy.

Trends in disaster safety research in Korea: Focusing on the journal papers of the departments related to disaster prevention and safety engineering

  • Kim, Byungkyu;You, Beom-Jong;Shim, Hyoung-Seop
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.10
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    • pp.43-57
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    • 2022
  • In this paper, we propose a method of analyzing research papers published by researchers belonging to university departments in the field of disaster & safety for the scientometric analysis of the research status in the field of disaster safety. In order to conduct analysis research, the dataset constructed in previous studies was newly improved and utilized. In detail, for research papers of authors belonging to the disaster prevention and safety engineering type department of domestic universities, institution identification, cited journal identification of references, department type classification, disaster safety type classification, researcher major information, KSIC(Korean Standard Industrial Classification) mapping information was reflected in the experimental data. The proposed method has a difference from previous studies in the field of disaster & safety and data set based on related keyword searches. As a result of the analysis, the type and regional distribution of organizations belonging to the department of disaster prevention and safety engineering, the composition of co-authored department types, the researchers' majors, the status of disaster safety types and standard industry classification, the status of citations in academic journals, and major keywords were identified in detail. In addition, various co-occurrence networks were created and visualized for each analysis unit to identify key connections. The research results will be used to identify and recommend major organizations and information by disaster type for the establishment of an intelligent crisis warning system. In order to provide comprehensive and constant analysis information in the future, it is necessary to expand the analysis scope and automate the identification and classification process for data set construction.

A Study on the Investment Efficiency of CB(Convertible Bond) (CB(전환사채)의 투자효율성에 관한 실증연구)

  • Sun-Je Kim
    • Journal of Service Research and Studies
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    • v.10 no.4
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    • pp.71-88
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    • 2020
  • CB(Convertible bond) is mezzanine security that have the characteristics of bonds and stocks. From the perspective of investors, the purpose of the research is to empirically investigate the degree of investment efficiency of CB and to suggest efficient investment plans. The research method investigated the maturity interest rate, conversion price, and conversion date for CB, and then linked it with daily stock price fluctuations after the conversion date to determine the degree of investment efficiency and stock conversion effect of CB. As a result of the study, it was analyzed that the ratio of the conversion price exceeded days was only about 1/4 of the conversion date, so the investment efficiency was low. The conversion day yield was -6.3% on average and the maturity day yield was -5.2% on average, showing a minus return on average, which was calculated differently from investor expectations. It was analyzed that the number of stocks with a minus conversion day is 2.4 times greater than the number of plus stocks and 3.7 times more than the number of plus stocks with a minus maturity return, so the expected return on stock conversion of CB is low. The research contribution was derived from the problem that the expected rate of return of CB is not high, and it is that the investor's point of view when purchasing CB was established.

A Comparative Analysis of Complex Disaster Research Trends Using Network Analysis (네트워크 분석을 활용한 국내·외 복합재난 연구 동향 분석)

  • Woosik Kim;Yeonwoo Choi;Youjeong Hong;Dong Keun Yoon
    • Journal of the Society of Disaster Information
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    • v.18 no.4
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    • pp.908-921
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    • 2022
  • Purpose: As the connection between physical and non-physical structures in cities is expanding and becoming more complex, the risk of complex disaster which causes damage in a complex way is increasing. Preparing for these complex disasters, it is important to preemptively identify and manage disasters that can develop into complex disasters. Therefore, this study analyzes the disaster types studied as complex disasters by analyzing the trends of domestic and international studies related to complex disasters, and presents the direction of complex disaster management in the future. Method: We first established co-occurrence networks between disaster types based on 993 articles related to complex disasters published in disaster-related journals for the last 20 years (2002-2021). Then, through network analysis, domestic and international complex disaster research trends were compared and analyzed. Result: Research on complex disasters related to storm and flood damage, infrastructure failure and fire was high in domestic studies, and it was analyzed that research on complex disasters related to earthquakes and landslides has recently increased. However, in international studies, the proportion of studies on infrastructure failure along with storm and flood damage and earthquake was high, and various types of disasters such as tsunami and drought appeared. Conclusion: The results of this study are expected to increase the understanding of the trends in complex disaster research and provide suggestions of domestic complex disaster research in the future.

MXene Based Composite Membrane for Water Purification and Power Generation: A Review (정수 및 발전을 위한 맥신(MXene) 복합막에 관한 고찰)

  • Seohyun Kim;Rajkumar Patel
    • Membrane Journal
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    • v.33 no.4
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    • pp.181-190
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    • 2023
  • Wastewater purification is one of the most important techniques for controlling environmental pollution and fulfilling the demand for freshwater supply. Various technologies, such as different types of distillations and reverse osmosis processes, need higher energy input. Capacitive deionization (CDI) is an alternative method in which power consumption is deficient and works on the supercapacitor principle. Research is going on to improve the electrode materials to improve the efficiency of the process. A reverse electrodialysis (RED) is the most commonly used desalination technology and osmotic power generator. Among many studies conducted to enhance the efficiency of RED, MXene, as an ion exchange membrane (IEM) and 2D nanofluidic channels in IEM, is rising as a promising way to improve the physical and electrochemical properties of RED. It is used alone and other polymeric materials are mixed with MXene to enhance the performance of the membrane further. The maximum desalination performances of MXene with preconditioning, Ti3C2Tx, Nafion, and hetero-structures were respectively measured, proving the potential of MXene for a promising material in the desalination industry. In terms of osmotic power generating via RED, adopting MXene as asymmetric nanofluidic ion channels in IEM significantly improved the maximum osmotic output power density, most of them surpassing the commercialization benchmark, 5 Wm-2. By connecting the number of unit cells, the output voltage reaches the point where it can directly power the electronic devices without any intermediate aid. The studies around MXene have significantly increased in recent years, yet there is more to be revealed about the application of MXene in the membrane and osmotic power-generating industry. This review discusses the electrodialysis process based on MXene composite membrane.

A Study on the Service Status of Public Domain Works in Digital Library: Focusing on the Case of the National Library of Korea's Expired Works Service (디지털도서관의 퍼블릭도메인 저작물 서비스 현황에 관한 연구: 국립중앙도서관의 보호기간 만료 저작물 서비스 사례를 중심으로)

  • Hosin Lee
    • Journal of the Korean Society for information Management
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    • v.40 no.3
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    • pp.119-142
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    • 2023
  • Copyright is a legal criterion for determining the scope and method of digital library service. Works with expired protection periods correspond to the public domain and can be freely used by anyone. For this reason, it is a priority consideration in digital library construction and services. The purpose of this study is to examine how actively libraries are using expired protected works for digital library services. To this end, the relevant provisions of the Copyright Act applied to the construction and service of digital libraries were first summarized, and the meaning of the copyright protection period was theoretically examined. The current status of online services for expired works by the National Library of Korea was examined, focusing on the works of three Japanese colonial era writers, Kim Yoo-jung, Lee Hyo-seok, and Chae Man-sik, to check the specific service status of expired works. It reveals that the National Library of Korea is not fully utilizing the scope of the law, and that this situation is linked to the rights of other authors included in the book. Based on these results, it suggests that there is a need to change the service unit to focus on copyrighted works and to use authority records to systematize the management of authors' death years.

Analysis of Research Trends in New Drug Development with Artificial Intelligence Using Text Mining (텍스트 마이닝을 이용한 인공지능 활용 신약 개발 연구 동향 분석)

  • Jae Woo Nam;Young Jun Kim
    • Journal of Life Science
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    • v.33 no.8
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    • pp.663-679
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    • 2023
  • This review analyzes research trends related to new drug development using artificial intelligence from 2010 to 2022. This analysis organized the abstracts of 2,421 studies into a corpus, and words with high frequency and high connection centrality were extracted through preprocessing. The analysis revealed a similar word frequency trend between 2010 and 2019 to that between 2020 and 2022. In terms of the research method, many studies using machine learning were conducted from 2010 to 2020, and since 2021, research using deep learning has been increasing. Through these studies, we investigated the trends in research on artificial intelligence utilization by field and the strengths, problems, and challenges of related research. We found that since 2021, the application of artificial intelligence has been expanding, such as research using artificial intelligence for drug rearrangement, using computers to develop anticancer drugs, and applying artificial intelligence to clinical trials. This article briefly presents the prospects of new drug development research using artificial intelligence. If the reliability and safety of bio and medical data are ensured, and the development of the above artificial intelligence technology continues, it is judged that the direction of new drug development using artificial intelligence will proceed to personalized medicine and precision medicine, so we encourage efforts in that field.

Path Algorithm for Maximum Tax-Relief in Maximum Profit Tax Problem of Multinational Corporation (다국적기업 최대이익 세금트리 문제의 최대 세금경감 경로 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.4
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    • pp.157-164
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    • 2023
  • This paper suggests O(n2) polynomial time heuristic algorithm for corporate tax structure optimization problem that has been classified as NP-complete problem. The proposed algorithm constructs tax tree levels that the target holding company is located at root node of Level 1, and the tax code categories(Te) 1,4,3,2 are located in each level 2,3,4,5 sequentially. To find the maximum tax-relief path from source(S) to target(T), firstly we connect the minimum witholding tax rate minrw(u, v) arc of node u point of view for transfer the profit from u to v node. As a result we construct the spanning tree from all of the source nodes to a target node, and find the initial feasible solution. Nextly, we find the alternate path with minimum foreign tax rate minrfi(u, v) of v point of view. Finally we choose the minimum tax-relief path from of this two paths. The proposed heuristic algorithm performs better optimal results than linear programming and Tabu search method that is a kind of metaheuristic method.

A Study on the Development Strategies of University Students in Sports Colleges by Evaluating Core Competencies (스포츠계열 대학생들의 핵심역량 평가에 따른 발전방안 연구)

  • Kim, Jin-Kook;Kim, Soo-Hyun
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.4
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    • pp.195-206
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    • 2019
  • The purpose of this study is to analyze the importance and performance of core competencies recognized by Korean sports students and to identify directions and methods for strengthening the competence of sports students in the future direction of future society. The results of analysis of 309 students of sports major students are as follows. First, the importance of core competencies recognized by college students in sports was in the order of self - management capacity, interpersonal capacity, communication capacity, comprehensive thinking ability, resource information technology utilization capability, and global capability. Second, the students' performance of their core competencies evaluated by sports college students was in the order of interpersonal competence, self-management competence, communication competence, comprehensive thinking ability, global competency, and resource information technology utilization competency. Third, the difference between the importance of core competence and the degree of performance was found to be significant in all areas, and the areas of great difference were total thinking, communication ability, resource information technology utilization capacity, self-management capability, Relationship competence. While college students in sports college have relatively high level of interpersonal competence, self-management competence and communication ability, comprehensive thinking ability, resource information technology utilization capacity and global competency are weak. Therefore, It will be able to be reborn as the talent required by society. Therefore, universities need to cultivate competitive sports talent through innovation of curriculum and capacity of faculty, and it should be recognized that this can be linked to the competitiveness of universities.