• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.94-103
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• 2020

This study investigated the effects of ultrasonic nanocrystal surface modification (UNSM) on the deteriorated surface of AISI SUS316L additively manufactured (AM) using the powder bed fusion (PBF) technique. Specifically, the effects of UNSM conditions on surface topology, hardness, and anti-corrosion were examined. Before UNSM treatment, the stainless steel 316L powder was processed via the PBF machine to prepare a substrate. We observed surface changes due to UNSM treatments in PBF SUS316L substrates and examined the correlation between topology changes, roughness, hardness, and anti-corrosion. After UNSM treatment, the coarse as-built surface was refined, and a regular micro-profile was implemented. Compared to the non-treated PBF sample, the waviness and roughness of the surfaces after UNSM treatment decreased by up to 56.0% and 94.5%, respectively, and decreased further as the interval decreased. The hardness improved by up to 63.0% at a maximum depth of 500 ㎛ from top surface by the UNSM treatment. The results of the corrosion test showed that the corrosion resistance of the UNSM specimens was moderately improved compared to that of the untreated surface. This study confirmed that UNSM is an effective post-processing technique for additively manufactured parts.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.653-658
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• 2021

Convergence of ICT technology and various industry have been proliferated. It makes human life affluent pulling existing industry paradigm down while they do not realize. Also, it impacts on personal life and becomes a driving force which strengthen the state level and its competitiveness. Complexity is increasing, knowledge is expanding and ICT technology is evolving in the present industrial society. Thus, new business model is being created, established business without competitiveness is eliminated and new ecosystem is constructed for industry change or creation. The new business and its competitive order driving in current convergence environment is apt to be exposed to uncertainty risk. These changes promote the collapse of existing industry or create new business models. There are digital transformation and ICT convergence in the center of the changes. The change of society and industry caused by this phenomenon will be analyzed. Also, development direction, strategy and execution method for securing industry competitiveness of ICT convergence will be researched.

• Laser Solutions
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• v.14 no.4
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• pp.21-27
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• 2011

In this work, we have studied on time-resolved transient reflective image of single crystalline Si surface after single-shot fs-laser irradiation with varying the laser fluence under two different laser spot sizes. The temporal profiles of transient reflectivity changes as well as its maximum values at the early delay time were found to be strongly dependent on both the laser beam spot size and laser fluence. We have interpreted the dependence of transient reflectivity changes on the laser spot size in terms of a relaxation of the generated free carriers to the bulk silicon, which should be interacted with the plasma.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.159-159
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• 2022

Soil represents a substantial component within the global carbon cycle and small changes in the SOC stock may result in large changes of atmospheric CO₂ particularly over tens to hundreds of years. In this study, we aim to (i) evaluate the SOC stock in the topsoil 0 - 15 cm from soil physical and chemical characteristics and (ii) find the correlation of SOC and soil organic matter (SOM) for national-scale in South Korea. First of all, based on the characteristics of the soil to calculate the soil hydraulic properties, SOC stock is the SOC mass per unit area for a given depth. It depends on bulk density (BD-g/cm³), SOC content (%), the depth of topsoil (cm), and gravel content (%). Due to insufficient data on BD observation, we establish a correlation between BD and SOC content, sand content, clay content parameter. Next, we present linear and non-linear regression models of BD and the interrelationship between SOC and SOM using a linear regression model and determine the conversion factor for them, comparing with Van Bemmelen 1890's factor value for the country scale. The results obtained, helps managers come up with suitable solutions to conserve land resources.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.332-341
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• 2023

Notable trends in the restaurant start-up market after the lifting of social distancing include increasing interest in start-ups, emphasizing the importance of food quality and diversity, decreasing the relative importance of delivery services, and increasing interest in certain industries. The data collection period is three years from April 2021 to May 2023, including before and after social distancing, and texts extracted from blogs, news, cafes, web documents, and intellectuals provided by Naver, Daum, and Google were collected. For the collected data, the top 30 words were derived through a refining process. In addition, based on April 2021, the application period of social distancing, data from April 2021 to April 2022, and data from May 2022 to May 2023, Through these changes in trends, founders can capture new opportunities in the market and develop start-up strategies. In conclusion, this paper provides important insights for founders in accurately understanding the changes in food service start-up trends and in developing strategies appropriate to the current market situation.

• Korean Journal of Social Welfare
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• v.59 no.4
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• pp.5-34
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• 2007

This study explores the effects of philanthropy education for elementary school students by using a mixed method. To examine the effects of philanthropy education, two different approaches in research methods are conducted with different data collected from different target groups on the same phenomenon: a) experimental designs to analyze students' change(prosocial behaviors) by philanthropy education program performed in a summer camp(43 participants) and elementary schools(162 students); and b) qualitative analysis on students' changes in perceptual, attitudinal, and behavioral aspects by students' diary and memorandum(66 participants) and intensive interviews with teachers(5 teachers) and parents(4 mothers). The analysis of both quantitative and qualitative results shows that philanthropy education has effects on students' changes in diverse aspects including prosocial behavior. First, the results of quantitative analysis show that in every component of the prosocial behavior such as helping, being kind, empathizing, sharing, protecting, and cooperating, students have positive changes after philanthropy education. Such changes are statistically significant as well. Second, the results of qualitative analysis show that students after having philanthropy education display positive changes in diverse aspects. Particularly, the quantitative results are converged with the qualitative results from students, parents, and teachers. On the other hand, unique finding from qualitative analysis is that students after having philanthropy education can have fundamental changes in their personality. Such a change is commonly confirmed by students, parents, and teachers. This study makes it possible to compare results or to validate, confirm, or corroborate quantitative results with qualitative findings on the effects of philanthropy education for students.

• Journal of Plant Biotechnology
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• v.47 no.3
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• pp.209-217
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• 2020

The presence of high amounts of seed storage proteins (SSPs) improves the overall quality of soybean seeds. However, these SSPs pose a major limitation due to their high abundance in soybean seeds. Although various technical advancements including mass-spectrometry and bioinformatics resources were reported, only limited information has been derived to date on soybean seeds at proteome level. Here, we applied a tandem mass tags (TMT)-based quantitative proteomic analysis to identify the significantly modulated proteins in the seeds of two soybean cultivars showing varying protein contents. This approach led to the identification of 5,678 proteins of which 13 and 1,133 proteins showed significant changes in Daewon (low-protein content cultivar) and Saedanbaek (high-protein content cultivar) respectively. Functional annotation revealed that proteins with increased abundance in Saedanbaek were mainly associated with the amino acid and protein metabolism involved in protein synthesis, folding, targeting, and degradation. Taken together, the results presented here provide a pipeline for soybean seed proteome analysis and contribute a better understanding of proteomic changes that may lead to alteration in the protein contents in soybean seeds.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.123-129
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• 2017

This study has been conducted to see influence of fibroid hepatic tissue on alpha-tocopherol and its histologic changes. Experimental groups were divided into 3 groups, one where fibrosis was caused by carbon tetrachloride and the other where alpha-tocopherol and carbon tetrachloride were administered together and another normal group. Results of test showed fibrosis reaction is weak compared to the group administered with carbon tetrachloride in the group administered with alpha-tocopherol. In conclusion, we could observe proliferation of collagen fibers through Hematoxylin&Eosin and Massom trichrom dye and increase in ALT, AST, ALP in fibroid hepatic tissues, indicating convergence anti-oxidation reaction by changes of alpha-tocopherol intake. Thus, it is considered that we can expect to utilize alpha-tocopherol as secondary treatment and find clinical meanings of diagnosis on hepatic diseases through results of this study.

• Parasites, Hosts and Diseases
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• v.62 no.3
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• pp.302-312
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• 2024

Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a major candidate for the blood-stage malaria vaccine. Genetic polymorphisms of global pfama-1suggest that the genetic diversity of the gene can disturb effective vaccine development targeting this antigen. This study was conducted to explore the genetic diversity and gene structure of pfama-1 among P. falciparum isolates collected in the Khyber Pakhtunkhwa (KP) province of Pakistan. A total of 19 full-length pfama-1 sequences were obtained from KP-Pakistan P. falciparum isolates, and genetic polymorphism and natural selection were investigated. KP-Pakistan pfama-1 exhibited genetic diversity, wherein 58 amino acid changes were identified, most of which were located in ectodomains, and domains I, II, and III. The amino acid changes commonly found in the ectodomain of global pfama-1 were also detected in KP-Pakistan pfama-1. Interestingly, 13 novel amino acid changes not reported in the global population were identified in KP-Pakistan pfama-1. KP-Pakistan pfama-1 shared similar levels of genetic diversity with global pfama-1. Evidence of natural selection and recombination events were also detected in KP-Pakistan pfama-1.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.23-33
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• 2012

This paper is a study on precise point positioning using global navigation satellite system. This paper studies inherent barriers of global navigation satellite system such as increase in shadowed areas and positioning errors when signals cannot be received due to various environmental factors. It analyzes performance of various receivers, changes in number of satellite and DOP(Dilution of Precision) following changes in environment such as center of a road, side of a road, residential area, high building, and alleys. It also studies changes in positioning error. The objective of this study lies on understanding the range of positioning error following changes in environment and the cause of error, and enhancing the reliability and safety of the global navigation satellite system.