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A Study on the Enhancement of Voice Match Based on Spectral-Contents Analysis
Hangil Kim,Kiman Jang,Hoe-Kyung Jung 한국정보통신학회 2015 2016 INTERNATIONAL CONFERENCE Vol.7 No.1
Researches on voice analysis have been in progress to verify the integrity of the original audio data. However, the spectrogram currently used or the technique for analyzing the frequency waveform has a problem of low accuracy in determining the voice match. In this paper, through voice analysis methods using the spectral content, we propose a method that can be performed and prove it by analyzing each individual’s unique audio-frequency shape and determining whether the voice is matched. Results for voice analysis and matching determination are to present a solution to voice-related disputes and crimes. In the IT industry, they are considered to have a wide range of applications in technology using a speech recognition device or a smart security device.
Scanning Photoemission Microscopy of Graphene Sheets on SiO<sub>2</sub>
Kim, Ki-jeong,Lee, Hangil,Choi, Jae-Hyun,Youn, Young-Sang,Choi, Junghun,Lee, Hankoo,Kang, Tai-Hee,Jung, M. C.,Shin, H. J.,Lee, Hu-Jong,Kim, Sehun,Kim, Bongsoo WILEY-VCH Verlag 2008 Advanced materials Vol.20 No.19
<B>Graphic Abstract</B> <P>Scanning photoemission microscopy (SPEM) images of a graphene flake as well as the C 1s core level spectra for the mono- and multilayer graphene are measured. The samples with lateral dimensions on the micrometer scale are prepared on a SiO<SUB>2</SUB> surface by direct exfoliation of crystalline graphite. Monolayer graphene is distinguished from the multilayer graphens through the chemical contrast images of SPEM. <img src='wiley_img/09359648-2008-20-19-ADMA200800742-content.gif' alt='wiley_img/09359648-2008-20-19-ADMA200800742-content'> </P>
Problem Posing in the Instruction of Proof: Bridging Everyday Lesson and Proof
( Hangil Kim ) 한국수학교육학회 2021 수학교육연구 Vol.24 No.3
Proof serves a critical role in mathematical practices as well as in fostering student’s mathematical understanding. However, the research literature accumulates results that there are not many opportunities available for students to engage with proving-related activities and that students’ understanding about proof is not promising. This unpromising state of instruction of proof calls for a novel approach to address the aforementioned issues. This study investigated an instruction of proof to explore a pedagogy to teach how to prove. The teacher utilized the way of problem posing to make proving a routine part of everyday lesson and changed the classroom culture to support student proving. The study identified the teacher’s support for student proving, the key pedagogical changes that embraced proving as part of everyday lesson, and what changes the teacher made to cultivate the classroom culture to be better suited for establishing a supportive community for student proving. The results indicate that problem posing has a potential to embrace proof into everyday lesson.
Surface property change of graphene using nitrogen ion
Kim, Ki-Jeong,Lee, Hangil,Choi, Junghun,Lee, Hankoo,Jung, Min Cherl,Shin, H J,Kang, T-H,Kim, B,Kim, Sehun IOP Pub 2010 Journal of Physics, Condensed Matter Vol.22 No.4
<P>We introduced nitrogen ions to modify the graphene surface and its property changes were investigated. A graphene layer grown on 6H-SiC(0001) was irradiated with 100 eV nitrogen ions. Surface property changes were studied using photoemission spectroscopy (PES), near edge x-ray adsorption spectroscopy (NEXAFS), and atomic force microscopy(AFM). N 1s core level spectra show that three kinds of nitrogen species, nitrogen gas, graphite-like and pyridine-like nitrogen were induced on the nitrogen ion implanted graphene surface. </P>
Secondary Teachers’ Views about Proof and Judgements on Mathematical Arguments
Hangil Kim 한국수학교육학회 2022 수학교육연구 Vol.25 No.1
Despite its recognition in the field of mathematics education and mathematics, students’ understanding about proof and performance on proof tasks have been far from promising. Research has documented that teachers tend to accept empirical arguments as proofs. In this study, an online survey was administered to examine how Korean secondary mathematic teachers make judgements on mathematical arguments varied along representations. The results indicate that, when asked to judge how convincing to their students the given arguments would be, the teachers tended to consider how likely students understand the given arguments and this surfaces as a controversial matter with the algebraic argument being both most and least convincing for their students. The teachers’ judgements on the algebraic argument were shown to have statistically significant difference with respect to convincingness to them, convincingness to their students, and validity as mathematical proof.
Annealing Effects after Nitrogen Ion Casting on Monolayer and Multilayer Graphene
Kim, Ki-jeong,Yang, Sena,Park, Youngchan,Lee, Myungjin,Kim, BongSoo,Lee, Hangil American Chemical Society 2013 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.117 No.5
<P>The modification of the electronic properties of a coverage-dependent graphene layer by nitrogen ions irradiation was investigated using core-level photoemission spectroscopy (CLPES). Here we describe preparation of monolayer and multilayer epitaxial graphene (EG) functionalized by nitrogen ions irradiation with 100 eV to minimize the damage of graphene layer as we annealed up to 1300 K to track the surface property changes using CLPES. As a result, on the monolayer EG, we found that pyridinic nitrogen mainly existed on the surface. On the multilayer EG, we observed the formation of graphitic nitrogen remaining as a major species confirmed using N 1s core-level spectra. Through a work function change (ΔΦ) measurement, both systems indicated p-type doping properties with 4.71 (monolayer EG) and 4.87 eV (multilayer EG) of work function values after N<SUB>2</SUB> ion irradiation. Interestingly, we observed that monolayer EG maintained its p-type doping character, whereas multilayer EG changed the doping character from p-type to n-type as we annealed both systems up to 1300 K due to the discrepancy of the electron charge transfer. We will systematically demonstrate these variations of electronic properties for both monolayer and multilayer EG.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2013/jpccck.2013.117.issue-5/jp309964m/production/images/medium/jp-2012-09964m_0006.gif'></P>
Kim, Hangil,Cho, Won Kyong,Lian, Sen,Kim, Kook-Hyung Elsevier 2017 Virus research Vol.235 No.-
<P><B>Abstract</B></P> <P>Rice stripe virus (RSV) is an important pathogen of rice. The RSV genome consists of four single-stranded RNA segments that encode seven viral proteins. A previous report found that NS3 is a viral suppressor of RNA silencing and self interacts. Using a model that predicts protein structure, we identified amino acid residues or motifs, including four α-helix motifs, required for NS3 self-interaction. We then used yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays to study the interactions between full-length NS3 and its truncated and alanine substitution mutants. Y2H and BiFC results showed that the N-terminal region of NS3 is essential for self-interaction. All α-helix deletion mutants and substitution mutants lost the ability to self-interact. To identify the relationship between NS3 self-interaction and silencing suppressor activity, we used a GFP silencing system in <I>Nicotiana benthamiana</I> with <I>Agrobacterium</I>-mediated transient overexpression of each mutated NS3 protein. All of the deletion and the α-helix substitution mutants that had lost the ability to self-interact also lost their silencing suppressor ability. The substitution of amino acids with alanine at positions 70–75, 76–83, and 173–177, however, resulted in mutants that were able to self-interact but were unable to function as silencing suppressors. These results suggest that RSV requires NS3 self-interaction to suppress RNA silencing and to thereby counter host defenses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We used a computer program to predict the structure of RSV NS3. </LI> <LI> We identified the aa residues or motif(s) required for RSV NS3 self-interaction. </LI> <LI> The N-terminal region (aa 1–108) of the NS3 is important for NS3 self-interaction. </LI> <LI> NS3 self-interaction is essential for the suppressor function of RSV NS3. </LI> </UL> </P>