• Journal of Information Technology Services
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• v.19 no.3
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• pp.117-137
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• 2020

The development of information technology leads to changes in various industries. In particular, the health care industry is more influenced so that it is focused on. With the widening of the health care market, the market of smart device based personal health care also draws attention. Since a variety of fitness applications for smartphone based exercise were introduced, more interest has been in the health care industry. But although an amount of use of mobile fitness applications increase, it fails to lead to a sustained use. It is necessary to find and understand what matters for mobile fitness application users. Therefore, this study analyze the reviews of mobile fitness application users, to draw key factors, and thereby to propose detailed strategies for promoting mobile fitness applications. We utilize text mining techniques - LDA topic modeling, term frequency analysis, and keyword extraction - to draw and analyze the issues related to mobile fitness applications. In particular, the key factors drawn by text mining techniques are explained through the concept of user experience. This study is academically meaningful in the point that the key factors of mobile fitness applications are drawn by the user experience based text mining techniques, and practically this study proposes detailed strategies for promoting mobile fitness applications in the health care area.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1600-1610
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• 2017

We propose maximum power extraction from a rooftop solar photovoltaic (PV) array during partial shading conditions. Partial shading is unavoidable during power extraction from rooftop PV systems due to nearby tall buildings (construction of additional floors) and trees (growth of trees). Many reconfiguration techniques can be used to extract maximum power in partial shading conditions, but in several cases, the real maximum power output is not achieved. In this study, a new switched PV technique is proposed to enhance the power output. The proposed technique is simple to use and more cost effective than other reconfiguration techniques. Therefore, it is suitable for rooftop applications. The power output of the proposed technique is compared with that of existing techniques with similar shading patterns. Eight panels with ratings of 250 watts (2 kW) each are used for testing. MATLAB simulation and hardware verification are done for the proposed and existing techniques. The proposed technique is implemented on a $4{\times}2$ PV array, although it can be extended to a number of arrays.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.1
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• pp.61-69
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• 2021

Background: Inferior alveolar nerve block (IANB) using lidocaine 2% is commonly used for anesthetizing primary mandibular molars; however, this technique has the highest level of patient discomfort compared to other local anesthesia techniques. Therefore, alternative anesthesia techniques are necessary. The aim of this study was to evaluate the efficacy of a single buccal infiltration of 4% articaine with IANB using 2% lidocaine, for the bilateral extraction of primary mandibular molars. Methods: The present study was conducted on 30 patients aged between 6 and 9 years, who required the extraction of bilateral primary mandibular molars. The patients were randomly divided into two groups as follows: In the first session, Group A received IANB with lidocaine 2% and group B received infiltration with articaine 4%. In the second session, another injection method was performed on the opposite side. The Wong-Baker Facial Pain scale (WBFPS), Face Leg Activity Cry, and Consolability (FLACC), and physiologic parameters were used to assess pain perception. Results: The independent t-test showed no statistically significant difference in blood pressure and heart rate before and after extraction (P > 0.05). The mean FLACC index in the lidocaine and articaine groups was 0.89 and 1.36, respectively; there was no statistically significant difference between them (P > 0.05). According to the results of the chi-square test, there was no statistically significant difference between the groups for WBFPS (P > 0.05). Conclusion: The articaine infiltration technique may be an alternative to the IANB for the extraction of primary mandibular molars.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.197-201
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• 2020

In order to enhance the extraction efficiency of flavonoid from Saururus chinensis, carbohydrate-hydrolyzing enzyme Viscozyme L aided extraction techniques have been studied. Then flavonoid composition, as well as quercetin, were also identified using UV/Vis, HPLC/MS, and ¹H-NMR. The results showed that favorable extraction conditions were Viscozyme L concentration of 0.25 mg/g, pH 4.2, reaction at 45 ℃ for 12 h. Under the favorable extraction condition, total flavonoid yield (37.9 mg/g) and quercetin yield (0.86 mg/g) increased by about 2.0 and 9.6 times, respectively, compared to control group. Interestingly, as a significant flavonoid of S. chinensis, flavonoid glycones rutin was hydrolyzed to aglycones quercetin by Viscozyme L. These findings provide scientific and theoretical support for the development quercetin-rich products, which was quickly absorbed by the human body than rutin.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.1
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• pp.45-56
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• 2020

Despite extensive research, performance enhancement of keyphrase (KP) extraction remains a challenging problem in modern informatics. Recently, deep learning-based supervised approaches have exhibited state-of-the-art accuracies with respect to this problem, and several of the previously proposed methods utilize Bidirectional Encoder Representations from Transformers (BERT)-based language models. However, few studies have investigated the effective application of BERT-based fine-tuning techniques to the problem of KP extraction. In this paper, we consider the aforementioned problem in the context of scientific articles by investigating the fine-tuning characteristics of two distinct BERT models - BERT (i.e., base BERT model by Google) and SciBERT (i.e., a BERT model trained on scientific text). Three different datasets (WWW, KDD, and Inspec) comprising data obtained from the computer science domain are used to compare the results obtained by fine-tuning BERT and SciBERT in terms of KP extraction.

• Journal of Korean Dental Science
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• v.9 no.2
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• pp.55-62
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• 2016

Purpose: Alveolar bone develops with tooth eruption and is absorbed following tooth extraction. Various ridge preservation techniques have sought to prevent ridge atrophy, with no superior technique evident. Collagen has a long history as a biocompatible material. Its usefulness and safety have been amply verified. The related compound, atelocollagen, is also safe and displays reduced antigenicity since telopeptides are not present. Materials and Methods: The current study evaluated whether the $Rapiderm^{(R)}$ atelocollagen plug (Dalim Tissen, Seoul, Korea) improves tissue healing of extraction sockets and assessed the sequential pattern of bone regeneration using histology and microcomputed tomography in six beagle dogs. To assess the change of extraction socket, hard tissues were examined 2, 4, 6, and 8 weeks after tooth extraction. Result: The experimental groups showed better bone fill with slow remodeling process compared to the control groups although there was no statistical difference between groups. Conclusion: The atelocollagen seems to have a tendency to slow bone remodeling in the early phase of healing period and maintain remodeling capacity until late phase of remodeling. Also, use of atelocollagen increased the bone-to-tissue ratio compared to healing of untreated extraction socket.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.636-647
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• 2016

Magnetite nanoparticles ($Fe_3O_4$ NPs) were synthesized by co-precipitating method under optimized condition. The $Fe_3O_4$ NPs coated with sodium dodecyl sulfate-thenoyltrifluoroacetone ($Fe_3O_4$ NPs-SDS-TTFA) were then exerted as the magnetic solid phase extraction (MSPE) adsorbent for the extraction process prior to introducing to a flame atomic adsorption spectrometry (FAAS). The synthesized $Fe_3O_4$ NPs-SDS-TTFA were applied for the extraction of Pb(II) ions from different water samples. The characterization studies of nanoparticles were performed via scanning electron microscopy-energy dispersive micro-analysis (SEM-EDAX), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) techniques. The substantial parameters affecting the extraction efficiency were surveyed and optimized. A dynamic linear range (DLR) of $10-400{\mu}g\;L^{-1}$ was obtained and the limit of detection (LOD, n=7) and relative standard deviation (RSD%, n= 6, $C=20{\mu}g\;L^{-1}$) were found to be $2.3{\mu}g\;L^{-1}$ and 1.9%, respectively. According to the results, the proposed method successfully applied for the extraction of Pb(II) ions from different environmental water samples and satisfactory results achieved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1403-1408
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• 2010

Korean information retrieval uses noun as index terms or keywords of representing the document. and noun and keyword extraction is to find all nouns presented in the document, In this paper, we proposes the method of keyword extraction using pre-built dictionary. This method reduces the execution time by reducing unnecessary operations. And noun, even large documents without affecting significantly the accuracy, can be extracted. This paper proposed noun extraction method using the appearance characteristics of the noun and keyword extraction method using unsupervised learning techniques.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.165-166
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• 2010

Noun extraction is to find all nouns presented in the document, Korean information retrieval uses noun as index terms or keywords of representing the document. In this paper, we proposes the method of keyword extraction using pre-built dictionary. This method reduces the execution time by reducing unnecessary operations. And noun, even large documents without affecting significantly the accuracy, can be extracted. This paper proposed noun extraction method using the appearance characteristics of the noun and keyword extraction method using unsupervised learning techniques.

• Journal of Powder Materials
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• v.28 no.2
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• pp.91-96
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• 2021

Rare earth magnets with excellent magnetic properties are indispensable in the electric device, wind turbine, and e-mobility industries. The demand for the development of eco-friendly recycling techniques has increased to realize sustainable green technology, and the supply of rare earth resources, which are critical for the production of permanent magnets, are limited. Liquid metal extraction (LME), which is a type of pyrometallurgical recycling, is known to selectively extract the metal forms of rare earth elements. Although several studies have been carried out on the formation of intermetallic compounds and oxides, the effect of oxide formation on the extraction efficiency in the LME process remains unknown. In this study, microstructural and phase analyses are conducted to confirm the oxidation behavior of magnets pulverized by a jaw crusher. The LME process is performed with pulverized scrap, and extraction percentages are calculated to confirm the effect of the oxide phases on the extraction of Dy during the reaction. During the L ME process, Nd is completely extracted after 6 h, while Dy remains as Dy₂Fe₁₇ and Dy-oxide. Because the decomposition rate of Dy₂Fe₁₇ is faster than the reduction rate of Dy-oxide, the importance of controlling Dy-oxide on Dy extraction is confirmed.