• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.443-455
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• 2013

Electrochemical studies on charge transfer reactions across the interface between two immiscible electrolyte solutions (ITIES) have greatly attracted researcher's attentions due to their wide applicability in research fields such as ion sensing and biosensing, modeling of biomembranes, pharmacokinetics, phase-transfer catalysis, fuel generation and solar energy conversion. In particular, there have been extensive efforts made on developing sensing platforms for ionic species and biomolecules via gelifying one of the liquid phases to improve mechanical stability in addition to creating microscale interfaces to reduce ohmic loss. In this review, we will mainly discuss on the basic principles, applications and future aspects of various sensing platforms utilizing ion transfer reactions across the ITIES. The ITIES is classified into four types : (i) a conventional liquid/liquid interface, (ii) a micropipette supported liquid/liquid interface, (iii) a single microhole or an array of microholes supported liquid/ liquid interface on a thin polymer film, and (iv) a microhole array liquid/liquid interface on a silicon membrane. Research efforts on developing ion selective sensors for water pollutants as well as biomolecule sensors will be highlighted based on the use of direct and assisted ion transfer reactions across these different ITIES configurations.

• Knowledge Management Research
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• v.22 no.4
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• pp.217-235
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• 2021

As 49% of the world's population uses social media platforms, communication and content sharing within social media are becoming more active than ever. In this environmental base, the one-person media market grew rapidly and formed public opinion, creating a new trend called sell-sumer. This study defined new types of influencers by product category by analyzing the subject concentration of the commercial/non-commercial keywords of influencers and the impact of the ratio of commercial postings on sales. It is hoped that influencers working within social media will be helpful to new sales strategies that are transformed into sell-sumers. The method of this study classifies influencers' commercial/non-commercial posts using Python, performs text mining using KoNLPy, and calculates similarity between FastText-based words. As a result, it has been confirmed that the higher the keyword theme concentration of the influencer's commercial posting, the higher the sales. In addition, it was confirmed through the cluster analysis that the influencer types for each product category were classified into four types and that there was a significant difference between groups according to sales. In other words, the implications of this study may suggest empirical solutions of social media sales strategies for influencers working on social media and marketers who want to use them as marketing tools.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.97-105
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• 2023

Concentration of nitrogen, one of the major elements, and ratio of two nitrogen forms (NH₄⁺ and NO₃^-) in the nutrient solution affect the quality and food safety of fresh vegetable produce. This study was conducted to find an appropriate strength and NH₄⁺:NO₃^- ratio of a nutrient solution for growth and development of a Romaine lettuce (Lactuca sativa L. var. longiflora) 'Caesar Green', a representative leafy vegetable, grown in a home hydroponic system. In the first experiment, plants were grown using three types of nutrient solution: A commercial nutrient solution (Peters) and two strengths (GNU1 and GNU2) of a multipurpose nutrient solution (GNU solution) developed in a Gyeongsang National University lab. Plants grown with the GNU1 and GNU2 had greater shoot length, leaf length and width, and biomass yield than Peters. On the other hand, the root hairs of plants grown with Peters were short and dark in color. Tissue NH₄⁺ content in the Peters was higher than that of the GNU1 and GNU2. The higher contents of NH₄⁺ in this solution may have caused ammonium toxicity. In the second experiment, eight treatment solutions, combining GNU1 and GNU2 solutions with four ratios of NO₃^- :NH₄⁺ named as 1, 2, 3 and 4 were used. Both experiments showed more growth in the GNU2 group, which had a relatively low ionic strength of the nutrient solution. The growth of Romaine lettuce showed the greatest fresh weight along with low tissue NO₃^- content in the GNU2-2. This was more advantageous in terms of food safety in that it suppressed the accumulation of surplus NO₃^- in tissues due to the low ionic trength of the GNU2 subgroup. In addition, this is preferable in that it can reduce the absolute amount of the input of inorganic nutrients to the nutrient solution.

• International Area Studies Review
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• v.22 no.1
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• pp.188-211
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• 2018

This study examined the problem of entrepreneurship education in Korea, which equate entrepreneurship with startups, unlike the global trend of approaching entrepreneurship with a broad concept. On the basis of overseas cases such as European Union and OECD, this study derived the need for entrepreneurship education from the perspective of thinking and behavioral patterns. In addition, Q methodology was used to reason out various recognition patterns and approach solutions for problems of entrepreneurship education in Korea, such as awareness of the need for entrepreneurship education in concepts separate from start-ups, reasons for infertility, and why it is difficult to activate. This approach was conducted for educators and educatees that carries out entrepreneurship education in Korea. In conclusion, there were four types of subjective perceptions about the difference of entrepreneurship education and startup education, and three types were recognized for the need to differentiate entrepreneurship education from startup education, and the two types that made up the upper majority strongly supported the need for entrepreneurship education to be implemented individually. According to the conclusion, this study proposed the development and spread of common teaching materials made by the Ministry of Education and Ministry of SMEs and Startups, which is the competent Ministry, to train professional teachers, training methods, and continuous refresher education. It also proposed that there should be a social atmosphere for eliminating rejection of entrepreneurship not only among the youth but also the adult population, and for continuous awareness of concepts that can be applied within the organization and the community, and that a policy basis is required to do so.

• Journal of Science Education
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• v.42 no.1
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• pp.12-26
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• 2018

This study examined the effects of SSI argumentation program on the preservice biology teachers' decision-making types and communication ability. The SSI argumentation program was developed based on 'Social Decision-Making & Problem-Solving strategy' and Toulmin's argumentation pattern. The preservice teachers had opportunities of SSI argumentation through small group discussions. They were asked to identify the issues regarding SSI, think of solutions, and make a decision along with claims, warrants, data, and rebuttals. The preservice biology teachers experienced four SSI topics of abortion, euthanasia, gene manipulation, artificial intelligence. The results indicated that the preservice biology teachers significantly improved the communication ability after the intervention, but they did not change their types of decision-making. In addition, after the intervention, the Pearson correlation results indicated that 'the logical type' of decision-making significantly relates to the communication ability(p<.01). The preservice biology teachers mentioned that they improved their ability of considering warrants, data, background information, context, and rebuttals. Further, the preserivce biology teachers mentioned that they became take an interest in socioscientific issues and improved their ability of accepting criticism from others as well as caring about others when they argue each other. This study implicated that the SSI argumentation program has effects on improving personality education in school science.

• Computers and Concrete
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• v.2 no.3
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• pp.203-214
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• 2005

In the Part 1 paper (Gawin, et al. 2005) some experimental results concerning micro-structural tests, permeability measurements and stress-strain tests of four types of High Performance Concrete, exposed to elevated temperatures (up to $700^{\circ}C$) are presented and discussed. On the basis of these experimental results parameters of the constitutive relationships describing influence of damage and temperature upon material intrinsic permeability at high temperature were determined. In this paper the effects of various formulations of damage-permeability coupling on results of computer simulations are analysed and compared with the results obtained by means of the previously proposed approach, that does not take into account the thermo-chemical concrete damage directly. Numerical solutions are obtained using the recently developed fully coupled model of hygro-thermal and damage phenomena in concrete at elevated temperatures. High temperature effects are considered by means of temperature and pressure dependence of several material parameters. Based on the mathematical model, the computer code HITECOSP was developed. Material parameters of the model were measured by several European laboratories, which participated in the "HITECO" research project. A model problem, concerning hygro-thermal behaviour and degradation of a HPC structure during fire, is solved. The influence of two different constitutive descriptions of the concrete permeability changes at high temperature, including thermo-chemical and mechanical damage effects, upon the results of computer simulations is analysed and discussed.

• KIEAE Journal
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• v.5 no.3
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• pp.11-16
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• 2005

The recent trends of high-density and high-rise in apartment housing have caused the problems of decrease in ventilation rates and increase of indoor pollutant contaminants. SHS(Sick House Syndrome) has now become a major issue and threats the health of residents. To solve these indoor air problems, increase in ventilation rate is considered as one of the most efficient approach. Thus, the recent housing development is pursuing improvement in the site design and the layout of apartment building blocks to promote natural ventilation is now investigated as one of the fundamental solutions. This study was focused on the air flow characteristics of outdoor environment in an apartment complex to keep the pollutants out of the site. Age of air and pressure difference have been used as indices of the outdoor air quality. Four different types of apartment building layouts have been analyzed by CFD simulation. This study again selected a real apartment housing complex as a case study model. By analyzing the pressure differences between the front and rear of an apartment building block, the ventilation performance in each individual unit was evaluated, and its impact on ventilation performance is investigated by analyzing the stagnant air around the apartment building blocks. During this process, existing patterns of apartment housing layout have been evaluated, and the most appropriate site layout has been chosen to analyze the outdoor airflow patterns. Based on the analysis of airflow patterns of site layout, the possibilities of improving ventilation performance of an individual apartment housing is proposed.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.593-605
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• 2023

This work presents a comparison between analytical and finite element analysis for bending of porous sandwich functionally graded material (FGM) plates. The plate is rectangular and simply supported under static sinusoidal loading. Material properties of FGM are assumed to vary continuously across the face sheets thickness according to a power-law function in terms of the volume fractions of the constituents while the core is homogeneous. Four types of porosity are considered. A refined higher-order shear with normal deformation theory is used. The number of unknowns in this theory is five, as against six or more in other shear and normal deformation theories. This theory assumes the nonlinear variation of transverse shear stresses and satisfies its nullity in the top and bottom surfaces of the plate without the use of a shear correction factor. The governing equations of equilibrium are derived from the virtual work principle. The Navier approach is used to solve equilibrium equations. The constitutive law of the porous FGM sandwich plate is implemented for a 3D finite element through a subroutine in FORTRAN (UMAT) in Abaqus software. Results show good agreement between the finite element model and the analytical method for some results, but the analytical method keeps giving symmetric results even with the thickness stretching effect and load applied to the top surface of the sandwich.

• Biomedical Science Letters
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• v.28 no.4
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• pp.298-306
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• 2022

Pathological tissue fixation using formalin has been widely used for histological samples in many hospitals and institutions. In general, formalin fixatives were either manufactured in laboratories or purchased commercially because of the risks and environmental concerns of handling organic compounds. In this study, the efficacy of three kinds of commercially purchased and one laboratory-made formalin fixative was compared in the PCR-based molecular diagnosis using the extracted DNA from formalin-fixed paraffin-embedded (FFPE) tissues. The quality of extracted DNA from FFPE tonsil tissues with four kinds of formalin solutions was evaluated, and PCR for beta-globin gene and microsatellite instabilities (MSI) tests for pentaplex panel markers were performed using the extracted DNA. There was no difference in PCR and MSI tests as molecular diagnoses regardless of the types of formalin used in this study. However, the total amount and average length of double-stranded DNA extracted from FFPE tonsil tissue showed significant differences according to the type of formalin fixative. Optimized formalin fixatives and methods for DNA extraction might be sophisticated to extract good quality DNA from the small size of specific tissue samples. Further studies are needed to select the most effective formalin fixative for histology and molecular pathology using human FFPE tissues.

• The Korean Journal of Archival Studies
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• no.54
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• pp.211-248
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• 2017

This study examined ways to improve records management by using the new technology of the Fourth Industrial Revolution. To do this, we selected four technologies that have a huge impact on the production and management of records such as cloud, big data, artificial intelligence, and the Internet of Things. We tested these technologies and summarized their concepts, characteristics, and applications. The characteristics of the changed production records were analyzed by each technology. Because of new technology, the production of records has rapidly increased and the types of records have become diverse. With this, there is also a need for solutions to explain the quality of data and the context of production. To effectively introduce each technology into records management, a roadmap should be designed by classifying which technology should be applied immediately and which should be applied later depending on the maturity of the technology. To cope with changes in the characteristics of production records, a flexible data structure must be produced in a standardized format. Public authorities should also be able to procure Software as a Service (SaaS) products and use digital technology to improve the quality of public services.