Determination of Carrier Concentration in Ga1-xMnxAs Using Raman Spectrocopy

명제 성,A Mascarenhas,Cheongy Cheongy,N Samarth,S. H. Chunz 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III

Ga$_{1-x}$Mn$_{x}$As with Curie temperatures ($T_c$) as high as 110 K has recently emerged as an important spintronic semiconductor material. The ferromagnetism in this material arises from the exchange interaction between the free carriers (holes) generated by Mn doping and the Mn$^{2+}$ ions. However, the accurate determination of the carrier concentration in Ga$_{1-x}$Mn$_{x}$As using standard transport techniques is extremely difficult because of the dominant anomalous Hall effect. We have performed spectroscopic measurements of the hole density in four Ga$_{1-x}$Mn$_{x}$As samples ($x = 0, 0.038, 0.061, 0.083$) using Raman scattering intensity analysis of the coupled plasmon-LO-phonon mode and the unscreened LO phonon. The unscreened LO phonon frequency linearly decreases as the Mn concentration increases up to 8.3 \%. The hole density determined from the Raman scattering exhibits a direct correlation to the observed $T_c$, providing an unambiguous means of determining the hole density in this important new class of ferromagnetic semiconductors.

Human Reasoning and Judgmental Errors

Cheongi Kim 경성대학교 산업개발연구소 2004 산업혁신연구 Vol.1 No.-

서로 다른 3차원 장면으로의 3차원 사람 동작 시퀀스 매핑

정천기(Cheongi Jeong),김영민(Youngmin Kim) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.6

전복과 광기의 담론: 『원더랜드에서의 앨리스의 모험』 읽기

윤천기 ( Yun Cheongie ) 대한영어영문학회 2011 영어영문학연구 Vol.37 No.1

Many critics have read Alice’s adventures in Wonderland as popular fantasies or fairy tales. This reading could be reached the nonsensical world of Alice’s world. But actually the Alice’s world is not nonsense at all because its underlying meanings are more complicated than fantasies or fairy tales show. Carroll questioned the value of order and principles in the world and explored their sophisticated meanings through ‘the satiric destruction of the common sense.’ By using both ‘episodic dream structures’ and ‘symbolic nonsenses,’ he deconstructed the boundaries of dream and real world, and reversed the order of the world. For Carroll, this was an effective narrative strategy. In fact, it is worth pointing out that the motifs of the reverse and madness in the Alice’s Adventures in Wonderland are almost dramatically composed. Carroll embodies them to create the sensical world beyond the reach of nonsense. ‘What he creates is a cosmic joke but it is more than a good joke’. Carroll shows us moral and philosophical insight into the world, which is based on Victorian society which have a disordered and disoriented world without God. (Seonam University)

대학 입학사정관전형의 편향성: 서울대 입학전형에서의 잠재력, 환경, 다양성 교육의 의미 구성

김천기(Kim Cheongie) 한국교육사회학회 2019 교육사회학연구 Vol.29 No.3

이 연구는 한국 대학에서 실시하는 입학사정관전형이 공정성이 확보된 전형인가 하는 문제의식에서 출발하였다. 특히 우리가 관심을 가지는 것은 서울대 입학사정관전형의 공정성 여부이다. 한국사회에서 서울대가 대학입시에서 차지하는 위상이 절대적이며, 서울대의 입시 공정성은 계층이동 사다리와 직접 연계되기 때문이다. 이 연구에서는 서울대 입학사정관전형에서 중시하는 학생 개인의 잠재력과 환경, 다양한 교육의 의미가 입학전형의 맥락에서 무엇인가를 밝히고자 하였다. 이 세 가지 요소의 의미 구성에 관심을 가지는 것은 이 의미 구성 속에 잠재력 등에 대한 인식의 편향성이 내재되어 있다고 판단되었기 때문이다. 본 연구결과, 비교과영역(수상경력 등)을 중시하기 시작했던 서울대의 2002학년도 입학전형방식은 입학사정관제의 원형이었으며, 입학사정관제가 도입된 이후에도 그 성격이 크게 달라지지 않았다. 입학사정관전형은 특목고 출신 학생에게 유리한 ‘특기자 전형’(전공 특기 전형)에서도 사용되었으며, 그 맥락 속에서 입학전형의 핵심적 요소인 ‘잠재력’ ‘의지’ ‘다양한 교육’에 대한 의미가 이항대립적인 구조 속에서 구성되었다. 그 이항 대립적 구조는 다음과 같았다. (1) 내신성적: 잠재력의 대립항 (2) 환경: 의지(적극적, 진취적 대처능력) 대립항 (3) 다양하고 창의적인 학교교육: 획일적인 학교교육 대립항이다. 입학사정관전형의 맥락에서 잠재력, 환경, 다양한 교육의 특정한 의미화는 학생 배경의 영향을 차단하고 순수한 잠재력과 의지를 평가할 가능성보다는 오히려 소득수준이 높은 가정과 ‘특수고’(특목고와 자사고 등) 배경을 가진 학생에게 유리한 편향성을 내포하고 있었다. The purpose of this study is to clarify the meanings of student’ potential and environment, and the meaning of diverse and creative education which are key elements that characterize the admission admissions system, in the context of admissions officer system. For this purpose, this study examines the characteristics of the admissions officer system of Seoul National University(SNU) and explores how the meanings of the key elements of admissions officer system are defined and used according to the type and purpose of admissions officer system. The semantics of the key elements in admissions are directly related to the admissions officer s evaluation of the student and can be beneficial or disadvantageous for a certain group of students. As a result of this study, the key elements that characterize the admission admissions system have been specifically defined in the context of the admission screening process. The actual meaning of the key elements used in the context of SNU s admission screening process has been embodied in the following binary relational structures. (a) potential: school records(scholastic achievement) (b) willingness (active, progressive coping ability): environment (c) various and creative school education: uniform school education. In the context of admissions officer system, the specific semantics of potential, environment (or will) and diverse education implies a bias favorable to families with higher income levels and students with ‘special school’ backgrounds rather than the possibility of blocking the influence of the student background and evaluating the pure potential and willingness.

『주홍색 연구』: 낭만적 범죄자의 불법화와 추리소설의 탄생

강관수(Kang, Kwansoo),윤천기(Yun, Cheongie) 신영어영문학회 2020 신영어영문학 Vol.77 No.-

Before a detective novel appeared, the voices of criminals were allowed. In the folktales and literary works, romantic offenders were praised as the heroes who rose against the ruthless rulers. However, they began to be perceived as a threat to a society as capitalism and the private property system were established. With the development of the capitalist society, they became criminals, and simultaneously a detective fiction was born. The important thing in the birth of a detective novel is that the public’s feeling of empathy goes not to transgressing romantic criminals, but to the detectives. This article focuses on the process of romantic criminals becoming illegal in A Study in Scarlet. In this work, a detective’s search for the murderer is seen as an act of practicing justice and a revenge for a lover’s death is a crime who violates the law. In doing so, a legal order is established and a criminal voice is oppressed and illegalized.

유튜브(Youtube) 크리에이터 초등학교 교사들의 정체성과 역할 구성에 대한 생애사 연구

최원준 ( Choi Wonjune ),김천기 ( Kim Cheongie ),이동성 ( Lee Dongsung ) 인하대학교 교육연구소 2021 교육문화연구 Vol.27 No.3

1인 미디어 시대의 도래로 미디어 플랫폼을 통한 초등학교 교사들의 콘텐츠 크리에이터 활동이 새로운 교육적 현상으로 나타나고 있다. 이 연구의 목적은 초등학교 교사의 유튜브 크리레이터 활동에 대한 생애사 연구를 통해 1인 미디어 활동 참여교사들의 정체성과 역할 구성을 사회문화적 관점에서 이해하는 데 있다. 이를 위해 연구자는 두 교사들을 대상으로 내러티브 인터뷰를 하였으며, 수집한 자료를 ‘실용적 절충주의에 의한 포괄적 분석 기법’을 통해 분석했다. 연구결과 그들은 두 가지 정체성과 그에 따른 역할을 구성하였다. 첫째, 연구 참여자들은 교육과정의 전달자에서 실행의 주체로 거듭났다. 이와 관련된 역할로 두 교사는 예술 장르를 활용해 교가 및 생활지도 교육 콘텐츠를 개발하였고, 학생의 주체성과 의미형성을 중심으로 교수·학습을 실천했다. 또한, 그들은 자신들의 교육과정 문해력을 통해 반성적 성찰을 시도했다. 둘째, 연구 참여자들은 교육 주체의 성장과 발달을 위한 구심점으로서 정체성을 구성하였다. 이와 관련한 역할로서 그들은 시·공간 확장 기반의 관계 형성으로 교육 인플루언서(influencer)가 되고자 하였고, 교육공동체의 발전을 위한 사회적·전문적 자본을 형성하였다. 1인 미디어 활동 참여교사는 의사표현의 자율성 강화, 학습자의 교육선택권 존중, 광범위한 관계 형성이라는 시대적 특성을 반영함으로써, 학교라는 제도적 환경에 안주하기보다 새로운 역할과 정체성을 끊임없이 탐색했다. With the advent of the one-person media era, the content creator activities of teachers through media platforms have become a new phenomenon. The purpose of this study is to understand the identity and role of teachers participating in one-person media activities from a social and cultural perspective through life history research of the two elementary school teachers' Youtube creator activities. To this end, the researcher conducted narrative interview with each of the two teachers, and analyzed the collected data through thematic analysis based on practical eclecticism. Firstly, the participants had been reborn as subjects of execution from the messengers of the curriculum. As a related role, the two teachers had developed teaching and life guidance education contents using the art genre, and practiced teaching and learning centering on the student's subjectivity and meaning construction. In addition, the two teachers had reflected on their curriculum literacy. Secondly, the two teachers had become the focal point for the growth and development of the educational subject. As a related role, they had become educational influencers by forming relationships based on time-space expansion, and had formed social and professional capital for the development of the educational community. Through this, the two teachers constantly searching for new roles and meanings rather than settling down in the institutional environment of schools, reflecting on the characteristics of the times, such as strengthening autonomy in expression of opinion, respecting consumers' right to choose, and establishing wide-ranging relationships.

비지도 학습을 이용한 3차원 관절형 대상의 핵심점 추출

배진석(Jinseok Bae),민철희(Cheol-Hui Min),정천기(Cheongi Jeong),김영민(Young Min Kim) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6

With the spread of commercialized depth cameras, it is becoming easier to obtain 3D data in everyday life. Thus, in recent years, massive works have been dedicated to find effective methods to embed 3D data into low-dimensional latent space with the help of state-of-the-art deep learning frameworks. In this paper, we introduce a method to express a sequence of 3D data with a sparse keypoint-based representation. The proposed network robustly extracts keypoints from given observations via discovering an optimal set of points that encodes both shapes and motions in sequence. Also, our method does not require any supervision, and allows frames of raw point cloud data as input. We evaluate our model by qualitive assessment of tracking and conditional generation task on DFAUST dataset.