• Title/Summary/Keyword: Jeon Chang-geun

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Development of Parameters for Diagnosing Laryngeal Diseases

  • Kim, Yong-Ju;Wang, Soo-Geun;Kim, Gi-Ryun;Kwon, Soon-Bok;Jeon, Kye-Rok;Back, Moo-Jin;Yang, Byung-Gon;Jo, Cheol-Woo;Kim, Hyung-Soon
    • Speech Sciences
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    • v.10 no.1
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    • pp.117-129
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    • 2003
  • Many people suffer from various laryngeal diseases. Since we can notice voice change easily, acoustic analysis can be helpful to diagnose the diseases. Several attempts have been made to clarify the relation between the parameters and the state of sick vocal folds but any decisive parameters are not found yet. The purpose of this study was to select and develop those parameters useful for diagnosing and differentiating laryngeal diseases. We examined eight MDVP parameters, and two additional MFCC and LPC parameters obtained from the production of an open vowel by 252 subjects with or without laryngeal diseases. Using a statistical procedure through the artificial neural networks, we attempted to differentiate laryngeal disease groups. Results showed that the LPC parameters indicated the highest differentiating rate by the networks followed by the MFCC and the MDVP parameters. In addition, Jita, Shim and NHR among the MDVP parameters came out better parameters in diagnosing laryngeal diseases.

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First Report of Gray Mold Disease on Endangered Species Cypripedium japonicum

  • Jeon, Chang-Wook;Kim, Da-Ran;Gang, Geun Hye;Kim, Byung-Bu;Kim, Nam Ho;Nam, Seong-Yeol;Kwak, Youn-Sig
    • Mycobiology
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    • v.48 no.5
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    • pp.423-426
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    • 2020
  • Cypripedium japonicum is known to be the indigenous plant to Korea, Japan, and China. However, C. japonicum represents the most critically endangered plant species in South Korea. The plant is esthetically pleasing due to its flower, which is larger than any other orchidaceous species. Disease symptoms relating to gray mold were observed on C. japonicum in May 2019. The suspected pathogen was successfully isolated from the symptomatic leaf tissue and conducted a pure culture of the fungi. The conidia formed consisted of a colorless or light brown single cell, which was either egg or oval-shaped with a size of 7.1 to 13.4 × 5.2 to 8.6 ㎛. Molecular phylogenetic relationship analysis was also confirmed that the pathogen concerned belonging to the family of Botrytis cinerea. Therefore, the findings confirmed that the pathogen isolated from C. japonicum was consistent with the unique properties of B. cinerea.

The Effects of Natural Disinfectants Naringin on Corneal Epithelium and Endothelium of Rabbit - By Scanning Electron Microscopy (천연보존제 나린진이 가토안의 각막 상피와 내피에 미치는 영향 - 주사전자현미경을 통한 고찰)

  • Kim, In-Suk;Yoo, Geun-Chang;Chae, Soo-Chul;Jeon, Chang-Jin
    • Journal of Korean Ophthalmic Optics Society
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    • v.10 no.1
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    • pp.63-69
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    • 2005
  • The effects of R products of B company and natural disinfectant naringin, well-known chemical disinfectant on Corneal endothelium and epithelium of rabbit were observed by scanning electron microscope. The main component of naringin is extract of grapefruit seed, which is one of the flavonoid widely recognized as natural antioxidants and used as preservative agent of food and cosmetics. The chemical disinfectants cytotoxicity in cell cultures were announced by MIT assay and LDH leakage assay. But there has been no study about that chemical disinfectants and natural disinfectants is inserted drops on rabbit's cornea directly. In this test R products B company and natural disinfectants has been dropped on the cornea of rabbits for one weeks and observed cytotoxiciy by light camera after rose bengal staining. Also, we analysed the damage of corneal epithelium and endothelium morphologically after enucleating the cornea by scanning electron microscope.

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Dunaliella salina as a Microalgal Biomass for Biogas Production (바이오 가스 생산을 위한 미세조류 바이오매스로서의 Dunaliella salina)

  • Jeon, Nayeong;Kim, Daehee;An, Junyeong;Kim, Taeyoung;Gim, Geun Ho;Kang, Chang Min;Kim, Duk Jin;Kim, Si Wouk;Chang, In Seop
    • Microbiology and Biotechnology Letters
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    • v.40 no.3
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    • pp.282-285
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    • 2012
  • In this study, the ability of Chlorella vulgaris and Dunaliella salina to use biomass resources for anaerobic digestive biogas production was examined. The differences in cell wall structure pretreatments affecting the yield of soluble products showed that D. salina is a better candidate for biogas production than C. vulgaris. There was no significant difference between pretreated and non-pretreated D. salina in terms of methane production yield by inocula obtained from anaerobic digestion systems. Therefore, D. salina is a suitable algal biomass for biogas production due to its high biomass productivity, simple pretreatment needs, and easy conversion to biogas.

The Analysis of Inquiry Activity in the Material Domain of the Elementary Science Textbook by Science and Engineering Practices (과학 공학적 실천에 의한 초등학교 과학 교과서 물질 영역의 탐구 활동 분석)

  • Cho, Seongho;Lim, Jiyeong;Lee, Junga;Choi, GeunChang;Jeon, Kyungmoon
    • Journal of Korean Elementary Science Education
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    • v.35 no.2
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    • pp.181-193
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    • 2016
  • We examined the inquiry activities in the material domain of the elementary science textbooks and experimental workbooks based on 2009 revised curriculum. The analysis framework was SEP (Science and Engineering Practices) - 'Asking questions and defining problems', 'developing and using models', 'planning and carrying out investigations', 'analyzing and interpreting data', 'using mathematics and computational thinking', 'constructing explanations and designing solutions', 'engaging in argument from evidence', and 'obtaining, evaluating, and communicating information'. Sub-SEP of each grade band were also used. The results showed that the $3^{rd}{\sim}5^{th}$ grade science textbooks and workbooks mainly emphasized 'make observations and/or measurements', 'represent data in tables and/or various graphical displays', or 'use evidence to construct or support an explanation or design a solution to a problem' among around 40 sub-SEP. In the case of the inquiry activities for $6^{th}$ grade, majority of sub-SEP included were also only 'collect data to produce data to serve as the basis for evidence to answer scientific questions or test design solutions', 'analyze and interpret data to provide evidence for phenomena' or 'construct a scientific explanation based on valid and reliable evidence obtained from sources'. The type of 'asking questions and defining problems', 'using mathematics and computational thinking' or 'obtaining, evaluating, and communicating information' were little found out of 8 SEP. Educational implications were discussed.

Rosai-Dorfman Disease as a Solitary Lesion of the Tibia (경골에 단독으로 발생한 Rosai-Dorfman병)

  • Kong, Chang-Bae;Lee, Jung-Wook;Cho, Sang-Hyun;Song, Won-Seok;Cho, Wan-Hyeong;Koh, Jae-Soo;Jeon, Dae-Geun;Lee, Soo-Yong
    • The Journal of the Korean bone and joint tumor society
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    • v.20 no.1
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    • pp.32-35
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    • 2014
  • Rosai-Dorfman disease (RDD) is an idiopathic histioproliferative disorder of lymph node and extranodal site. Bone involvement is very rare. We report a case of extranodal RDD of the tibia in 32-year old male. The patient presented with pain with no evidence of lymphadenopathy. Clinico-radiologic diagnosis was metastatic carcinoma or Langerhans cell histiocytosis, but, histopathologic examination confirmed the diagnosis with RDD. We performed curettage on the osteolytic lesion of tibia. In South Korea, there was no report about RDD of the extremity and we want to report this case with review of the literature.

Performance Analysis of Channel Compensation and Channel Coding Techniques based on Measured Maritime Wireless Channel in VHF-band Ship Ad-hoc Network (VHF 대역 선박 간 애드혹 네트워크에서 실측 해상채널에 기반한 채널 보상과 채널 부호화 기법의 성능분석)

  • Jeon, Kwang-Hyun;Hui, Bing;Chang, Kyung-Hi;Kim, Seung-Geun;Kim, Sea-Moon;Lim, Yong-Kon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.5B
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    • pp.517-529
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    • 2011
  • In this paper, the parameters of the RTT (Radio Transmission Techniques) for SANET (Ship Ad-hoc NETwork), which is considered for the next generation maritime communication systems, are set up. A channel model has been analyzed based on the practical measured maritime wireless channel in VHF (Very-High Frequency) for SANET system. Also, by considering the frame structure including preamble, guard time and pilots for both single and multi-carrier systems, the BER (Bit Error Rate) performances are evaluated and analyzed in the aspects of channel compensation and channel coding techniques. Based on the simulation results, optimal modulation & coding schemes are suggested for SANET. That is, in single-carrier system by using differential modulation schemes, channel compensation is not necessary. However, channel coding is helpful to achieve additional gain. On the other hand, when 16-QAM modulation is employed in multi-carrier system, the implementation of both channel compensation and channel coding techniques show huge performance gain for various of K values, which are related to different maritime environments, and the rolling effects of wave.

Effects of Glass Frit Size on the Sintering Behavior of Cu Termination Paste in MLCC (Glass Frit의 입도가 MLCC 외부전극 Paste의 소결거동에 미치는 영향)

  • Lee, Kyu-Ha;Jeon, Byung-Jun;Kim, Chang-Hoon;Kwon, Young-Geun;Park, Myung-Jun;Gu, Hyun-Hee;Uhm, Ji-Won;Kim, Young-Tae;Hur, Kang-Heon
    • Journal of the Korean Ceramic Society
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    • v.46 no.2
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    • pp.175-180
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    • 2009
  • Multilayer ceramic capacitors (MLCCs) have continually been made smaller in size and larger in capacity in resent years. However, the end termination electrode is still thick in many MLCCs. In this study, we used small grain glass frit to embody thin film and highly densification in the end termination by improve sintering driving force with well-dispersion and rising surface energy. Pastes were fabricated using size changed glass frit, such as 0.1 ${\mu}m$, 0.5 ${\mu}m$, 1.0 ${\mu}m$, 4.0 ${\mu}m$. Fabricated pastes were applied 05A475KQ5 chip and fired various sintering temperatures to analyze sintering behavior of pastes. Consequently, small glass frit used pastes have many merits than larger, such as well-dispersion, improve cornercoverage and surface roughness, possibility of low temperature sintering. However, we confirmed that small glass frit used pastes have narrow sintering window by rapid completion of sintering densification.

Synthesis and Luminescent Characteristics of Anthracene Fluoroionophores (안트라센 형광 단위를 가지는 Fluoroionophore의 합성 및 발광특성)

  • Jeon Young-Min;Kim Jong-Gyu;Jang Ji-Geun;Chang Ho-Jung;Kim Yung-Sup;Gong Myoung-Seon
    • Polymer(Korea)
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    • v.30 no.5
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    • pp.426-431
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    • 2006
  • Novel azacrown ether containing blue -light emitting anthracene fluorophore, 9,10-bis [p-(1-aza-18-crown-6)methylphenyl] anthracene (3) and N,N-bis [9-(p-methylphenyl) anthracenyl-methyl] -1,6-diaza-18-crown-6 (4) were prepared by reacting anthracene derivatives 1 and 2 with mono- and diaza-18-crown-6, respectively Also, crown ether containing fluorophore copolymer (5) were prepared by reacting 1,6-diaza-18-crown-6 with 1. Their fluorescence emission spectral studies were investigated by binding group I, group II and various metal cations. The fluorophores showed an absorption at ${\lambda}_{max}$= 372 nm and an emission at ${\lambda}_{max}$= 430 nm. pH Dependency of fluorescence emission intensity were examined to determine the optimum pH for the fluorophores.

Estimation Formula for Shear Strength of RCS Beam-Column Joint (RCS 보-기둥 접합부의 전단강도 산정식 평가)

  • Chang, Kug-Kwan;Jeon, Choong-Geun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.1-9
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    • 2015
  • This study is on the shear strength of the internal joints of RCS composite structure consisting of reinforced concrete column and steel beam. As a newly structure system, the composite system has been developed to fully utilize the advantages of reinforced concrete column and steel beam, which also include economic and practical joint detail. Nevertheless stress transfer mechanism and structural behavior of the joints had not been still clearly revealed and shown much difference from the proposed equation. In this study, by observing the crossing of reinforced concrete column through steel beam to the RCS structure beam type, thirty seven shear failure specimens were selected and applied to the 5 major equations which is used to calculate the shear strength of RCS joint. Through the regression analysis, modified equation which is more reliable and approximate results for shear strength of RCS joints was proposed.