예비 초등영어 교사의 교수유형의 변화 및 교수유형과 학습유형의 관계 분석

김재혁,Kim Jaehyuk 한국초등영어교육학회 2015 초등영어교육 Vol.21 No.2

The purpose of this study is to suggest ways to diversify the teaching styles of pre-service elementary English teachers by investigating their teaching and learning styles. Specifically, this study intends to examine a) how the teaching styles of pre-service elementary English teachers change during their practicum and, b) how their learning styles are related to their teaching styles. Two teaching styles questionnaires (one before the practicum and another after the practicum) and a learning styles questionnaire were designed and distributed to a sample of 34 pre-service English teachers at a university in Korea who took their teaching practicum in their senior year. The analysis of the data revealed that before the practicum, the facilitator style, a learner-centered approach that views the teacher’s role as a facilitator of student learning, was the dominant, preferred teaching style. However, after the practicum, the subjects developed a more positive attitude toward the personal model style, a teacher-centered approach that views the teacher’s role as more of an authority in presenting information. The data also revealed that some of their learning styles were significantly related to their teaching styles. Those with individual, dependent and collaborative learning styles were found to prefer the facilitator teaching style, but those with group, independent and competitive learning styles tended to use the personal model style. These findings suggest that pre-service teachers try teaching in the styles they are reluctant to use in order to diversify their teaching styles in the classroom. Pedagogical implications for teacher education are also discussed.

Curet과 Ultrasonic Scaler를 이용한 치주치료후 SEM과 EPMA를 이용한 잔존치근면에 대한 연구

김재혁,김종여,임성빈,정진형,Kim, Jae-Hyuk,Kim, Chong-Yeo,Lim, Sung-Bin,Chung, Chin-Hyung 대한치주과학회 1999 Journal of Periodontal & Implant Science Vol.29 No.2

One of the fundamental causes of periodontal disease is accumulation of bacterial plaque and calculus and most effective method of removing these plaque and calculus are scaling and root planning using hand curet and ultrasonic scaler. Many studies concerning residual degenerated mineral content after periodontal therapies have been carried out, but some problems about these studies were also known. This research studies mineral concents and distribution of residual root surfaces after perfoming hand curet and ultrasonic scaler on root surfaces of single rooted teeth which were extracted for periodontal reasons. EPMA were used to avoid errors from chemical quantative analysis and in addition SEM observation was also performed. The results were as follows. 1. No differences were found between curet group andultrasonic scaler group in Ca, P, Mg and Na level. 2. Concentration level was decreased in the sequence of Ca, P, Mg and Na. 3. Ca and P level were decreased as going to apical portion at curet group and ultrasonic scaler group. 4. More cementum was removed at cervical portion compared to other portion at curet group and ultrasonic scaler group. 5. Ca, P, Mg level was higher in dentin compared to cememtum. There was no difference in mineral level for Ca, P, Mg and Na between root surfaces treated with hand curet and ultrasonic scaler.

Li₂O-Bi₂O₃ 첨가가 Pb(Mg_1/3Nb_2/3)_0.65Ti_0.35O₃ 세라믹의 압전 특성에 미치는 영향

김재혁,김시연,최정식,여동훈,신효순,남산,Kim, Jae Hyuk,Kim, Shi Yeon,Choi, Jeoung Sik,Yeo, Dong-Hun,Shin, Hyo-Soon,Nahm, Sahn 한국분말야금학회 2019 한국분말재료학회지 (KPMI) Vol.26 No.5

Piezoelectric ceramic specimens with the $Pb(Mg_{1/3}Nb_{2/3})_{0.65}Ti_{0.35}O_3$ (PMN-PT) composition are prepared by the solid state reaction method known as the "columbite precursor" method. Moreover, the effects of the $Li_2O-Bi_2O_3$ additive on the microstructure, crystal structure, and piezoelectric properties of sintered PMN-PT ceramic samples are investigated. The addition of $Li_2O-Bi_2O_3$ lowers the sintering temperature from $1,200^{\circ}C$ to $950^{\circ}C$. Moreover, with the addition of >5 wt.% additive, the crystal structure changes from tetragonal to rhombohedral. Notably, the sample with 3 wt.% additive exhibits excellent piezoelectric properties ($d_{33}=596pC/N$ and Kp = 57%) and a sintered density of $7.92g/cm^3$ after sintering at $950^{\circ}C$. In addition, the sample exhibits a curie temperature of $138.6^{\circ}C$ at 1 kHz. Finally, the compatibility of the sample with a Cu electrode is examined, because the energy-dispersive X-ray spectroscopy data indicate the absence of interdiffusion between Cu and the ceramic material.

궤도상 위성의 광학관측가능성 해석을 위한 궤도전파 시뮬레이터 개발

김재혁,조중현,박찬덕,박상영,문홍규,임홍서,최영준,최진,박장현,Kim, Jae-Hyeok,Jo, Jung-Hyeon,Park, Chan-Deok,Park, Sang-Yeong,Mun, Hong-Gyu,Im, Hong-Seo,Choe, Yeong-Jun,Choe, Jin,Park, Jang-Hyeon 한국천문학회 2012 天文學會報 Vol.37 No.2

이 연구는 우주물체에 대한 광학감시 및 추적을 수행하기 위한 선행연구로, 궤도전파 시뮬레이터를 개발하여 궤도상 위성의 광학관측가능성을 분석하고 광학관측 여부를 판단하는 것을 목표로 한다. 연구의 주 내용은 주어진 궤도정보를 바탕으로 하는 태양동기궤도(Sun-Synchronous Orbit; SSO) 위성, Dawn-dusk 위성, 저궤도(Low Earth Orbit; LEO) 위성, 정지궤도(Geostationary Orbit; GEO) 위성 등 궤도상 위성의 추정궤도 전파와 자국위성의 광학관측가능성 분석으로 구성된다. 각각의 궤도전파 정밀도 및 광학관측가능성 분석성능을 확인하기 위해 AGI(Analytical Graphics Incorporated)사의 STK(Satellite Tool Kit) 시뮬레이션 프로그램을 사용하여 개발된 궤도전파 시뮬레이터와 비교하였다. 시뮬레이션 과정에서 광학관측의 제한조건을, 지구반영(penumbra)과 태양직사광(direct sun)에서만 관측하며, 고도(elevation angle)의 최소값은 20도, 태양고도(Sun elevation angle)의 최대값은 -10도로 설정하였다. 광학관측이 이루어지는 가상의 관측소는 임의로 선정하였으며, 기본적인 관측시간은 1년으로 잡고, 계절의 변화에 따른 광학관측가능성 궤적의 변화를 보기위해 춘하추동에 대해서 각각 3일이내의 기간 동안 시뮬레이션을 수행하였다. 결과적으로, 우주물체 광학감시 및 추적을 수행하기 위한 광학관측가능성 분석성능은 궤도전파 시뮬레이터 및 초기궤도요소 정밀도, 좌표변환과정 오차 등의 영향을 받으며, 설정된 제한조건에 따라 광학관측 지속시간의 차이가 발생한다. 연구결과를 통해 궤도상 위성의 궤도를 추정하기 위한 위성의 궤도전파 시뮬레이터를 개발하고, 자국위성의 관측가능성 분석을 통해 광학감시 및 추적시스템의 운영이 원활히 이루어질 수 있도록 한다.

매식체 표면처리에 따른 생물학적 특성에 대한 연구

김재혁,정진형,임성빈,홍기석,Kim, Jae-Hyuk,Chung, Chin-Hyung,Lim, Sung-Bin,Hong, Ki-Seok 대한치주과학회 2008 Journal of Periodontal & Implant Science Vol.38 No.3

Purpose: The purpose of this research is to study about initial adhesion, proliferation and activation of osteoblast to titanium surface treated with machined, hydroxyapatite coating, resorbable blast material blasting and anodizing method. Material and Methods: After treating the titanium surface of each block with machined, impurities were removed and sterilized. The number of cells attached from cultured osteoblast of respective experimental groups were measured at 1, 4, 7, and 14day and alkaline phosphatase, calcium, and inorganic phosphate concentration of cultured solution was measured. Result: Anodizing group showed the highest rate of cell attachment and proliferation activity. RBM treated group showed the highest increasing on their alkaline phosphatase activity, on the calcium apposition, on inorganic phosphate apposition of 1 and 4 days in cultured osteoblast to compare with other groups. Conclusion: On the basis of these findings, we conclude that surface modification of titanium was profoundly effected on the attachment, proliferation and activation of osteoblast in initial stage osseointegration.

그리드포밍 제어 방식을 적용한 MMC HVDC 시스템의 전력 진동 감쇠 성능 분석

김재혁(Jae-hyuk Kim),김형승(Hyung-seung Kim),김현준(Hyun-jun Kim),이준철(Jun-chol Lee),정홍주(Hong-ju Jung) 전력전자학회 2023 전력전자학술대회 논문집 Vol.2023 No.7

저녹스버너 보급사업에 따른 오염물질 저감효과 분석 및 발전방안

김재혁(Jae Hyuck, Kim),김장원(Jang Won, Kim),김형석(Hyung Seok, Kim),이광호(Kwang Ho, Lee),유경선(Kyung Seun, Yoo) 한국환경정책학회 2014 環境政策 Vol.22 No.1

DDS에서 효율적 데이터전송을 위한 네트워크전송기술

김경태(Kyeong Tae Kim),이수형(Soo Hyung Lee),전형국(Hyung-Kook Jeon),김재혁(Jae Hyun Kim),김용연(Yong Yeon Kim),김원태(Won-Tae Kim),박승민(Seung-Min Park) 제어로봇시스템학회 2011 제어로봇시스템학회 합동학술대회 논문집 Vol.1 No.1

최근 네트워크 중심전(NCW)으로 발전하는 국방기술분야에 대규모 실시간 데이터 통신을 위해 미들웨어 표준기술인 DDS(Data Distribution Service)가 적용되고 있다. 하지만 기존 DDS 기술은 국방체계통신객체를 탐색하는 시간이 오래 걸리고, 실시간성을 보장하는 대규모 고신뢰 통신에 한계를 나타내며, 모빌리티가 발생하는 무선통신환경을 고려하지 않고 있다. 따라서 본 논문에서는 DDS에서 보다 효율적인 데이터 전송을 위한 네트워크전송 기술을 제안하였다. 제안된 기술은 DDS 상호운영성을 위반하지 않으면서도 1) 통신객체고속탐색, 2) 실시간 고신뢰성을 위한 하이브리드 멀티캐스팅, 3) 무선통신환경에서 모빌리티 지원을 위한 네트워크통신을 지원한다.

문학 속의 유토피아: 릴케와 백석과 윤동주 - 시적 주체와 공간의식의 관점에서

김재혁 ( Kim Jae Hyeok ) 한국헤세학회 2011 헤세연구 Vol. No.

Im Mittelpunkt dieser Untersuchung steht eine ausführliche Analyse des Phänomens, dass sich in den Gedichten „An der weißgestrichenen Wand“ von Baek Shuk (1912-1995) und „Eine Sterne aufzählende Nacht“ von Yoon Dong Ju (1917-1945) seltsamerweise die Namen von Francis Jammes und Rainer Maria Rilke jeweils in einer Zeile nebeneinander finden. Bis zum jetzigen Zeitpunkt war dieses erstaunliche Phänomen nie Gegenstand einer wissenschaftlichen Untersuchung gewesen. Ausgangspunkt der vorliegenden Untersuchung bilden die dichterischen Identitäten der beiden koreanischen Dichter. Am Ende steht eine Analyse des Ziels, das sie in ihren Werken verfolgt haben. Im Vordergrund dieser Studie stehen die lyrischen Aspekte, die man in den Gedichten der beiden koreanischen Dichter feststellen kann, und das wahre Wesen der Utopie, die die beiden anstrebten. Wir analysieren die beiden Gedichte unter Zuhilfenahme der Konzepte ‚Erinnerung‘ und ‚Lyrisches‘ von Emil Staiger und ‚Poetik des Raumes‘ von Gaston Bachelard und Friedrich Bollnow. Nachdem geklärt worden ist, warum die Namen Francis Jammes und Rainer Maria Rilke in den beiden Gedichten gleichzeitig erscheinen, wendet sich die vorliegende Studie der Frage zu, welche Funktion Begriffe wie ‚Erinnerung‘ und ‚Lyrisches‘ unter der Rahmenbedingung der Heimat oder des Hauses haben und in welchem Zusammenhang diese Begriffe mit der literarischen Utopie stehen, die die beiden koreanischen Dichter angestrebt haben. Als Ergebnis lässt sich festhalten, dass Baek Shuk und Yoon Dong Ju von der idyllischen Stelle in Rilkes „Die Aufzeichnungen des Malte Laurids Brigge“ in japanischer Fassung, die ihrerseits einen großen Einfluss Francis Jammes‘ aufweist, stark beeinflusst sind. Da sich das Subjekt der oben genannten vier Dichter allesamt im utopisch eingebildeten Raum befindet, wird das Konzept von Gaston Bachelard und Friedrich Bollnow bezüglich des Raums als Werkzeug der weiteren Analyse eingesetzt. Die Gedichte von Baek und Yoon lassen sich problemlos unter die Kategorie der Lyrik im Sinne von Emil Staiger einzuordnen, weil in ihnen der seelische Abstand des Subjekts von dem lyrischen Objekt deutlich ausgeschlossen ist, und rhythmische Kontrolle durch lautliche Wiederholung und der in ihr innenwohnende Atmung lyrische Atmosphäre hervorruft. Die Grundform der Lyrik hat die Struktur der Erinnerung und diese Struktur ermöglicht dem Dichter eine tiefgreifende Reflexion über sich selbst. Indem der Dichter in den Raum der Erinnerung seine Bilder einer idealen Welt hineinwirft, baut er sich eine literarische Utopie. Diesen Umstand kann man nicht nur bei Baek Shuk und Yoon Dong Ju, sondern auch bei Francis Jammes und Rainer Maria Rilke finden. Wenn die Namen Francis Jammes und Rainer Maria Rilke gleichzeitig in Gedichten bei Baek Shuks und Yoon Dong Jus auftauchen, kann man dieses seltsame Phänomen dadurch erklären, dass die beiden in dem Werk des deutschen Dichters Rainer Maria Rilke, der seine Wesensverwandtschaft mit dem französischen Dichter Francis Jammes in einem Brief an Lou Salome bekannt hat, Vorstellungen und Ideen formuliert fanden, die ähnlich ihrer eigenen waren. Für die beiden koreanischen Dichter stellt das lyrische Schreiben einen träumenden und zugleich eigene Erinnerungen idealisierenden Akt dar. Der utopische Raum ist bei den beiden koreanischen Dichtern ein psychologischer und literarisch realisierbarer Raum im Innern des Dichters.

세탁시설 VOCs 관리현황 고찰 및 정책제언

김재혁(Jae Hyuck, Kim),유경선(Kyung Seun, Yoo) 한국환경정책학회 2015 한국환경정책학회 학술대회논문집 Vol.2015 No.10