패널 자료의 인과 추론을 위한 비볼록 벌점화 행렬 완성 방법

학위논문(박사) -- 서울대학교대학원 : 자연과학대학 통계학과, 2023. 8. 김용대.Low-rank matrix completion is a widely used approach for imputing missing entries of a matrix. The nuclear norm penalty, which shrinks the singular values of a matrix, is often employed due to its computational convenience. However, it introduces bias in the estimation. To address this issue, nonconvex penalties such as SCAD are utilized, which provide sparse and unbiased estimators. In this thesis, we study the nonconvex penalized matrix completion methods for estimating causal effects in panel data with time-dependent treatment adoption. We first derive an upper bound for the estimation error of our proposed estimator for the potential control outcomes, which improves upon existing methods that rely on the nuclear norm penalty. Remarkably, this upper bound matches the one obtained by the oracle estimator, under an additional condition on the magnitudes of true singular values. Furthermore, we establish the asymptotic normality of the corresponding estimator for the treatment effect, which exhibits a smaller asymptotic variance compared to an existing method. We perform numerical studies to assess the recovery of the potential control outcomes and the estimation of the average treatment effect. Simulations validate our theoretical results, and experiments using real data further demonstrate the promising performance of our proposed method.Low-rank 행렬 완성은 행렬의 누락된 성분을 채우기 위해 널리 사용되는 방법이다. 행렬의 특이값 크기를 축소하는 nuclear norm 벌점화는 계산 편의성 때문에 일반적으로 사용되나, 추정에 편향을 발생시킨다. 이 문제를 해결하기 위해 SCAD와 같은 비볼록 벌점화가 사용되며, 이는 성기고 편향되지 않은 추정량을 제공한다. 본 학위 논문은 시간 의존적 처리 (치료) 채택 구조를 갖는 패널 자료에서 인과 효과를 추정하기 위해 비볼록 벌점화 행렬 완성 방법을 연구한다. 우리는 먼저 nuclear norm 벌점화에 의존하는 기존 방법을 개선하는 잠재 제어 행렬에 대해 제안된 추정량의 추정 오류에 대한 상한을 도출한다. 놀랍게도, 이 상한은 참 특이값의 크기에 대한 추가 조건이 주어졌을 때 오라클 추정량이 얻는 상한과 일치한다. 또한 치료 효과에 대한 추정량의 점근적 정규성과, 이 추정량이 기존 방법에 비해 더 작은 점근 분산을 갖는다는 것을 증명한다. 우리는 잠재 제어 행렬의 복구와 평균 치료 효과의 추정을 평가하기 위해 수치 연구를 수행한다. 시뮬레이션은 우리의 이론적 결과를 검증하고, 실제 자료를 사용한 실험은 제안 방법의 유망한 성능을 입증한다.Abstract i 1 Introduction 1 2 Review: low-rank matrix completion 5 2.1 Introduction 5 2.2 Setup and notation 7 2.3 Low-rank matrix approximation 9 2.4 Low-rank matrix completion 10 2.4.1 Rank constraint 10 2.4.2 Nuclear norm penalty 11 2.4.3 Nonconvex penalty 13 2.5 Theoretical studies for low-rank matrix completion 15 2.5.1 Assumption 1: Coherence 15 2.5.2 Assumption 2: Spikiness 16 2.5.3 Review of existing studies 18 2.6 Algorithms for low-rank matrix completion 20 2.6.1 SOFT-IMPUTE algorithm 20 2.6.2 PGH algorithm 21 3 Nonconvex penalized matrix completion for causal inference in panel data 26 3.1 Introduction 26 3.2 Setup and notation 28 3.3 Review of existing matrix completion methods 30 3.3.1 Nuclear norm penalized estimator for the potential control outcomes 30 3.3.2 De-biased estimator for the average treatment effect 33 3.4 The proposed estimator 35 3.5 Theoretical results 37 3.5.1 Recovery of the potential control outcomes 37 3.5.2 Estimation of the average treatment effect 44 3.6 Numerical studies 47 3.6.1 Recovery of the potential control outcomes 47 3.6.2 Estimation of the average treatment effect 54 4 Conclusions 59 Bibliography 61 A Appendix A. 70 A.1 Computation of the PGH algorithm 70 B Appendix B. 72 B.1 Proof of Theorems 72 B.1.1 Proof of Theorem 3.5.1 72 B.1.2 Proof of Theorem 3.5.2 77 B.1.3 Proof of Theorem 3.5.3 83 B.1.4 Proof of Theorem 3.5.4 83 B.1.5 Proof of Theorem 3.5.5 85 B.2 Proof of Lemmas and Proposition 88 B.2.1 Proof of Lemma B.1.2 88 B.2.2 Proof of Lemma B.1.5 93 B.2.3 Proof of Proposition 3.5.6 96 C Appendix C. 98 C.1 Comparison with the Synthetic control method 98 Abstract (in Korean) 106박

루돌프 라반의 합무단에서 현대적 커뮤니티 댄스로의 이행을 중심으로

학위논문 (석사) -- 서울대학교 대학원 : 인문대학 협동과정 공연예술학전공, 2021. 2. 신혜경.This study analyzes community dance as a practice that reflects the community nature of the respective society. To this end, it sheds light on Rudolph Laban's Movement Choir, which is the beginning of community dance, and analyzes the changes in community and practice that are found in the process of transition to modern community dance. Furthermore, this study examines the social role that contemporary community dance practice aims to perform. In terms of contemporary practice, community dance can be defined as "participatory dance activities by non-experts under the guidance or cooperation of dance professionals." Community dance participants can communicate with community members through these activities to inspire individual achievement or to achieve healing effects. Community dance is distinguished from professional dance in terms of dancing subjects, the purpose of movement, and evaluation, and is distinctive from folk dance and ballroom dance as it does not require conventionally defined skills or steps. Community dance can be seen as a dance practice that emerged in the 20th century, based on Laban's theory, which originated in Germany and was synthesized in the UK under the influence of American post-modern dance. Laban, who founded the Non-Professional Dance movement in the early 20th century, expanded the dancing body to non-expert students and workers, unlike previous dances, and embodied the ideal community through formation and choreography. In particular, the format of Movement Choir, which connects improvisation and free dancing to the collective movement, Reigen, can be seen as a unique structure in which Laban's thoughts about individuals and communities are expressed. What he emphasized was the interaction between community members, and for this reason, Movement Choir was used in areas such as education and industry and unlike works of artists, it entered the public domain where anyone could participate, not the works of artists, and acquired characteristics of a community practice. However, the fact that Movement Choir was used as a means of policy for the Nazis and Laban's history of contributing to it are pointed out as reasons why Movement Choir cannot be reproduced today. It is undeniable that the Nazis used Movement Choir format and formalized it as a community dance, and that Laban cooperated with it. However, the community that Laban and the Nazis wanted to implement through Movement Choir was different from the Nazis. If the Nazis wanted to worship the ruler through the unified movement of the group and boast the image of a strong Germany to the outside, Laban wanted to share the integrated experience of the people by having the German people dancing together. In particular, the connection between Movement Choir and modern community dance can be found in that Laban respects the unique movements of individuals and pursues communities that are created through interaction between participants rather than subordination to society. Indeed, Movement Choir promoted individuals to follow leaders and melt into the whole rather than pursue complete individuality, and limited participants to healthy young people centered around the notion of the nation as a community. Such facts can be seen as the limitation of Movement Choir. The modern community dance has evolved to reflect on and overcome this. Community dance, which succeeded Movement Choir, has developed to reflect changes in the concept of community shared by society, encompassing various members of society that have been excluded by expanding the concept of community based on diversity beyond nationality, gender, race and age. As a result, the purpose of community dance has expanded to not only enhance the sense of belonging but also to select and create communities on their own. Community dance is widely used in various areas of society in that it aims to achieve individual transformation and further change the community in which the individual belongs. As a result, the social role of community dance is gradually emphasized, which is used for remedial activities and for mental healing and physical therapy, and the practical nature is strengthened, for example communicating with the disabled through dance or trying to overcome generational differences. In line with this trend, consideration of the political characteristics of community dance is required. As Movement Choir, collective movement of citizens can be a powerful means of delivering messages, so delicate consideration and review of political and social characteristics are needed not only for practitioners but also for participants in community dance practice. Today, community dance is presented for various purposes and forms, including experiments and performances by famous artists, state-funded welfare policies, and means of treatment and self-development. This study sought to identify the nature of community dance and discover values that run thorough community dance practices in various aspects and factors that current practices should overlook. By examining changes in the notion of community and analyzing aspects of practice in community dance, we will be able to reason how it should develop in the future, and further produce critical reflections both in domains of research and practice.본 논문은 커뮤니티 댄스를 해당 사회의 공동체성을 반영한 실천으로서 분석한다. 이를 위해 커뮤니티 댄스의 시초라 할 수 있는 루돌프 라반의 합무단을 조명하고, 현대적 커뮤니티 댄스로 이행되는 과정에서 발견되는 공동체성과 실천 방향의 변화를 분석한다. 나아가 동시대 커뮤니티 댄스 실천이 지향하는 사회적 역할을 검토한다. 동시대 실천 경향을 종합해 보면, 커뮤니티 댄스란 ‘무용 전문가의 지도 혹은 협력 하에 이루어지는 비전문가들의 참여적 춤 활동’으로 규정할 수 있다. 참여자들은 이러한 활동을 통해 개인적 성취감을 고취시키거나 치유의 효과를 얻고, 공동체 구성원과 소통하게 된다. 커뮤니티 댄스는 춤추는 주체와 움직임의 목적, 평가에 이르기까지 전문 무용과 구별되며, 관습적으로 규정된 기술이나 스텝이 없다는 면에서 민속춤, 사교춤과도 구별되는 특성을 지닌다. 즉, 커뮤니티 댄스는 20세기에 출현한 고유한 무용 실천으로 볼 수 있으며, 이는 라반의 이론을 바탕으로 독일에서 발생해 미국 포스트모던 댄스의 영향을 받아 영국에서 종합되었다. 20세기 초 비전문가 무용 운동을 창시한 라반은 춤추는 주체를 비전문가인 학생과 노동자들로 확장시켰고, 대형과 안무를 통해 이상적인 공동체의 모습을 구현했다. 특히 즉흥과 프리댄스에서 라이겐 대형의 집단 움직임으로 연결되는 합무단의 형식은 라반이 가진 개인과 공동체에 대한 이상이 표현된 구조로 볼 수 있다. 그가 강조한 것은 공동체 구성원 간의 상호작용이었으며, 이러한 이유로 합무단은 교육, 산업 등의 영역에 활용되며 예술가의 작품이 아닌 누구나 참여할 수 있는 공공의 영역으로 진입하며 공동체 실천으로서의 특성을 획득할 수 있었다. 그러나 합무단이 나치의 정책 수단으로 이용되었다는 사실과 이에 기여한 라반의 이력은 합무단이 동시대에 그대로 재현될 수 없는 이유로 지적된다. 이 같은 역사를 부정할 수는 없지만, 라반과 나치가 합무단을 통해 구현하고자 한 공동체의 모습은 상이했다. 나치가 집단의 통일된 움직임을 통해 지배자를 경배하고 강한 독일을 외부에 과시하고자 했다면, 라반은 독일인들이 함께 춤을 추는 행위를 통해 민족의 통합된 경험을 공유하고자 했다. 특히 라반이 개인의 고유한 움직임을 존중하고 참여자들 간의 상호작용을 통해 만들어가는 공동체를 추구했다는 점에서 합무단과 현대적 커뮤니티 댄스의 연결성을 발견할 수 있다. 물론 완전한 개성보다 지도자를 따라 전체 안에 녹아드는 개인을 표현했고, 국가 공동체를 중심으로 신체 건강한 청년으로 참여자를 한정시킨 점은 합무단의 한계로 볼 수 있으며, 현대적 커뮤니티 댄스는 합무단을 계승하는 동시에 반성하고 극복하는 방향으로 발전되어 왔다. 커뮤니티 댄스는 시대에 따른 공동체 개념의 변화를 반영해 발전해 왔는데, 동시대 커뮤니티 댄스는 20세기 초의 제한된 공동체 개념을 확장해 다양성을 기반으로 그동안 배제해 왔던 구성원을 포섭하고 있다. 이에 따라 커뮤니티 댄스의 목적은 소속감을 높이는 것은 물론 스스로 공동체를 선택하고 만들어가는 것으로 확장되었다. 커뮤니티 댄스는 개인의 변화를 이루고 나아가 그 개인이 속한 공동체의 변화를 목표로 삼는다는 점에서 사회의 여러 영역에서 폭넓게 활용되고 있다. 이에 따라 커뮤니티 댄스의 사회적 역할은 점차 강조되고 있으며, 교정은 물론 정신적 치유나 육체적 치료 차원에서도 활용되고, 춤을 통해 장애인과 소통하거나 세대차이 극복을 시도하는 등 실천적 성격이 강화되고 있다. 이런 경향과 맞물려 커뮤니티 댄스가 필연적으로 가지는 정치적 특성에 대한 고려가 요구되는데, 합무단이 그랬듯 시민의 집단 움직임은 메시지를 전달하는 강력한 수단이 될 수 있으므로, 커뮤니티 댄스 실천에 있어 실행가는 물론 참여자들에게도 정치적·사회적 특성에 대한 섬세한 배려와 검토가 필요하다 하겠다. 오늘날 커뮤니티 댄스는 유명 예술가의 실험과 공연, 국가의 지원을 받는 복지 정책, 치료와 자아 개발 수단 등 다양한 목적과 형태로 선보이고 있다. 본 논문은 커뮤니티 댄스의 본성을 파악해 커뮤니티 댄스 실천을 관통하는 가치를 발견하고자 했다. 이를 통해 커뮤니티 댄스가 앞으로 어떻게 발전해야 하는지를 사유하고, 나아가 연구와 실천 양쪽에 있어서 비판적으로 성찰할 수 있을 것이다.서론 1 Ⅰ. 예비적 고찰 : 커뮤니티 댄스에 대한 이해 9 Ⅰ.1. 20세기 이후의 커뮤니티 댄스 개념 9 Ⅰ.2. 서구 사회의 커뮤니티 댄스 실천 14 Ⅰ.2.1. 독일의 커뮤니티 댄스 발생과 단절 14 Ⅰ.2.2. 미국의 공동체 기반 포스트모던 댄스 19 Ⅰ.2.3. 영국의 커뮤니티 댄스 계승과 종합 23 Ⅰ.3. 국내 커뮤니티 댄스 도입과 실천 양상 27 Ⅱ. 라반의 커뮤니티 댄스 개념과 공동체성 33 Ⅱ. 1. 공동체 춤으로서의 합무단 33 Ⅱ.1.1. 라반의 커뮤니티 댄스 개념 33 Ⅱ.1.2. 합무단 형식에 구현된 공동체의 모습 40 Ⅱ.2. 합무단의 사회적 이용 43 Ⅱ.2.1. 사회 문제 해결을 위한 합무단 이용 43 Ⅱ.2.2. 라반과 나치의 커뮤니티 댄스 개념 비교 48 Ⅲ. 동시대 커뮤니티 댄스의 변화와 확장 56 Ⅲ.1. 공동체를 조성하는 춤으로서의 커뮤니티 댄스 56 Ⅲ.1.1. 합무단의 계승과 교육무용의 대두 56 Ⅲ.1.2. 공동체 개념의 변화와 확장 61 Ⅲ.2. 동시대 커뮤니티 댄스의 지향성 66 Ⅲ.2.1. 커뮤니티 댄스의 사회적 역할 66 Ⅲ.2.2. 커뮤니티 댄스 형식의 정치사회적 특성 76 결론 81 참고문헌 86 Abstract 94Maste

Dilemma and Breakthrough in the Port ODA of Korea

In accordance with the globalization age, countries in the world try to dedicate to collaboration between them through ODA(Official Development Assistance) in order to solve the-rich-get-richer and the poop-get-poorer among countries, to develop the developing countries' economy and to improve their level of social welfare. Korea is also active in ODA as the member of OECD/DAC and recently importance of ODA in the field of ports has been brought into relief and it in the initial process. However, if the giving countries' assistance repeats unconditionally, the developing countries become to expect and believe that the developed countries would help them again in case of problems and have no inspirations or motivation to make their efforts in order to solve the problems or to develop economy by themselves. In this case, the 'system' play an important role to provide motivations to their action. These ODA situation can be explained by the model of 'Samaritan's Dilemma' by Buchanan. The model is deal with in the perspective of game theory and previous literatures discussed just issue of motivation of ODA under the one-shot game. However, substantial ODA situations occur very repeatedly and issue of information as well as that of motivation can affect occurrence of dilemma. Therefore, through model of dilemma including both repeated game situations and information problem, occurrence structure of dilemma of ODA may be understood. Accordingly, the study analyze dilemma structure of ODA in the field of ports applying point of view of new institutionalism and game structure of Samaritan's dilemma and seeks improvements of system to create effective results based on it. As the results, first, regarding to information system, the system to acquire information on the assisted countries is not well organized. And without any specific agencies with assignment,there is lack of specific information and it takes longer time to prepare contractions and its execution. And because collaboration between governmental ministries are weak, there may be overlapping in assignments. The field inquiry system is consideratively poor and there is limit to acquire accurate information in the field, as well. And then there is no system to observe corruptions due to invisible activities by the assisted countries. So systematic management by professionals and institutional arrangement for professionalism and efficiency are required and system to acquire information including seminars between related countries and related commissions should be consolidated. In regard to the field inquiry, it should enhance the assistance system focusing on the field and if necessary, it may be considered to assign right of the field inquiry to multilateral assistance organizations. The system to observe corruptions in the assisted countries should be introduced, too. Second, concerning pay-off system, Korea can be compensated by mutual assistance with the assisted country, economical compensation, human right compensation and higher image in international society. The assisted country can get economic compensation from construction of harbors. In case of construction of harbors, it cannot be executed by the government only and it requires assistance by professional construction companies or public organizations. Accordingly, there has been a transitional stage to prepare legal and policy systems to lead collaboration with them. And there are no legal and official policy and unofficial systems to require the assisted countries' efforts. So it is necessary to reorganize and establish related legal and policy systems in order to collaborate related companies and public organizations in Korea. And in order to induce collaboration with the assisted country, it needs to introduce systems of providing obligation including participation in project of inviting trainees after concluding contract on constructing harbors, adjusting property compensation of the assisted countries or giving compensation according to their efforts. Third, in regard to choice systems, even though officials in charge of assistance in both Korea and the assisted countries can choose various strategies(actions) about ODA, they tend to continue to conclude ODA repeatedly. Accordingly, the assisted countries become to expect future assistance and as assistance is repeated, they tend to request assistances from the giving country. Therefore, in order to induce the assisted country's self-efforts, it needs to establish systems to minimize the assistance or to provide bigger compensation in case of efforts by the assisted country. And if the assisted country shows no will to create effective results of the project or its attitude is negligent in the process of the project, it may be considered to introduce the system to stop the project and not to provide assistance in the future. Hence, the study has its own significance in restructuring, suggesting and analyzing the dilemma model of ODA and based on the results, it will contribute to theoretical development of ODA. And it analyzes the system of Korean ODA in the field of ports and makes suggestions to improve it, it is expected to contribute to create efficient results of ODA in the field of ports.제 1 장 서론 1 제 1 절 연구의 배경 및 목적 1 1. 연구의 배경 1 2. 연구의 목적 2 제 2 절 연구의 범위 및 방법 3 제 2 장 이론적 논의 및 연구의 분석틀 4 제 1 절 공적개발원조(ODA)의 정의 4 1. 국제사회(OEDC/DAC)에서 ODA의 정의 4 2. 우리나라에서 ODA의 정의 6 제 2 절 ODA 운영상 비효과성의 문제 10 1. 정보 문제 11 2. 동기부여 문제 14 3. 선행연구의 검토 및 최근 연구동향 22 제 3 절 사마리아인의 딜레마 24 1. 개념적 고찰 24 2. 게임이론 관점에서의 사마리아인의 딜레마 25 3. 선행연구의 검토 및 최근 연구동향 31 제 4 절 연구의 분석틀 32 1. 접근 방법 32 2. 게임의 맥락으로서의 제도 33 3. 분석틀 39 제 3 장 우리나라 ODA의 특성과 항만분야 ODA 현황 40 제 1 절 우리나라 ODA의 특수성 40 1. 수원국으로서의 대한민국 41 2. 공여국으로서의 대한민국 42 3. 우리나라 ODA의 문제점 46 제 2 절 우리나라의 항만분야 ODA 현황 52 1. 우리나라의 항만분야 ODA 수원 현황 52 2. 우리나라의 항만분야 ODA 공여 현황 54 제 4 장 항만분야 ODA의 딜레마 발생구조 62 제 1 절 정보 제도 62 1. 우리나라의 정보문제 62 2. 수원국의 정보문제 66 제 2 절 보상 제도 67 1. 협력으로 인한 보상 67 2. 현행 보상제도 68 제 3 절 선택 제도 73 제 4 절 딜레마 발생구조 76 1. 게임구조 자체적 특성 76 2. 제도적 맥락 76 제 5 장 항만분야 ODA의 효과성 제고를 위한 제도개선 방향 78 제 1 절 정보제도의 개선방안 79 1. 정보획득 체계 정비 79 2. 현지조사체제 강화 81 3. 수원국의 부패 감시체제 수립 82 제 2 절 보상제도의 개선방안 82 1. 국내기업 및 공공기관에의 보상제도 정비 83 2. 수원국의 협력 유도를 위한 보상체제 확립 83 제 3 절 선택제도의 개선방안 84 1. 수원국의 자구노력을 위한 제도 마련 84 2. 신뢰할 수 있는 협박 85 제 6 장 결론 87 제 1 절 연구의 요약 87 제 2 절 연구의 한계 및 향후연구과제 89 참 고 문 헌 9

The study of helping behaviors in coworker relationship

학위논문 (박사)-- 서울대학교 대학원 : 경영학과, 2011.2. 박오수.Docto

한국 영어학습자의 모국어 배경과 영어능력이 영작문 헤징 표현 사용 양상에 미치는 영향

학위논문 (석사)-- 서울대학교 대학원 인문대학 영어영문학과, 2017. 8. 이용원.Ever since first defined by Lakoff (1973) as words whose job is to make things fuzzier or less fuzzy (p. 471), the concept of hedges has consequently widened in a way to modify the speaker/writers commitment to the truth-value of a whole proposition (Markkanen & Schröder, 1997) and eventually to realize an interactional and communicative strategy called hedging, a product of social forces. In the latter approach where hedges are treated as purposive imprecise language, hedging signals distance, unobtrusively injects an authors personal view into his communication (Dubois, 1987, p. 539), and protects the writers reputation by avoiding absolute statements. Such tentativeness eludes personal responsibility for statements, reducing the authors degree of liability (Hübler, 1983, p. 18). Hedges have crucially been concerned with academics whose claims are inevitably framed as tentative. They enable writers to present unproven claims with caution and to enter a dialogue with their audience (Hyland, 1998a, p. 6). With the growing interest in interlanguage pragmatics and the inseparability of language and culture (Roberts, 1998, p. 109), intercultural communicative awareness and the ability to use pragmatic knowledge strategically have further been highlighted in second language learning scene. Despite its significant status in academic society, however, interpreting and using hedges appropriately have repeatedly been reported to be difficult for learners, especially in academic writing where EFL writers tend to unfold a collection of facts in a direct and impersonal manner (Bloor & Bloor, 1991Dudley-Evans, 1991Hyland, 2000aKamimura & Oi, 2006Oh, 2007Skelton, 1988). The present study was motivated in search of diagnostic analysis on the problematic areas of hedges for Korean EFL learners and thus aims to provide suggestions for ways to guide them toward the skillful use of hedging. The data used for the research were extracted from the International Corpus Network of Asian Learners of English (ICNALE). From a total of 1,300 participants, 2,600 essays were collected and examined. The participants were composed of four language groups: The Korean learner group along with two other learner groups with East Asian native language backgrounds, and the native speaker group from five different English-speaking countries. All the participants of the study were classified into one of the four English proficiency levels (or score bands) defined in this study, which has enabled the analysis of the effect of proficiency factor as well as language factor on the pattern of hedging usage. The results resonate with findings from previous studies that native speakers employ hedging markers at a higher frequency than ESL/EFL learner writers do (Aijmer, 2002Baumgarten & House, 2010Hyland, 1995Skelton, 1988). The findings direct attention to three aspects of EFL writing with regard to their usage and pattern of hedging expressions. The EFL learners were found to be dependent on a restricted number of hedging devices than the native speakers for the very nature of the target language itself, including the semantic, pragmatic, form complexity, and saliency. The rise in EFL proficiency was accompanied by the broader range of hedging devices available to the learners, although it did not prove to affect the frequency in a consistent manner. Finally, the Korean learners, whom we refer to as the learner group in focus, were observed to be strong and assertive in tone, which points to their lack of experience in manipulation of expressing tentativeness in their claims. Another problem in the area of stylistic aspects was diagnosed in terms of mixed use of written and spoken registers. Several theoretical and pedagogical implications for EFL teaching and assessment can be drawn from the present study. First, the present study provides a piece of evidence that supports the proficiency impact on the use of two lexical pairs. Second, the correlation of proficiency with the lexical pairs can possibly contribute to the development of automated writing evaluation system, particularly to the identification of the features of styles that can be quantified and used in automated scoring. Third, explicit instruction on hedging is needed in EFL settings, an aspect which has largely been neglected in Korean English classrooms. Lastly, regular English writing practice sessions should take place in order to familiarize the learners with the stylistic features present in academic genres of discourse.Chapter 1 Introduction 1 1.1 Motivation of the Study 1 1.2 Research Questions 3 1.3 Organization of the Study 4 Chapter 2 Literature Review 5 2.1 The Concept of Hedging and Its Categorization 5 2.1.1 Hedging: From Semantics to Pragmatics 5 2.1.2 Linguistic Realizations of Hedging 10 2.1.3 Classification of Epistemic Hedges 14 2.2 Hedging in Second Language Writing 18 2.3 Learner Corpus and Corpus-Based Study 25 Chapter 3 Method 32 3.1 Corpora and Participants 32 3.2 The Selection/Classification Scheme for Hedges 34 3.3 Procedure and Method of Data Analysis 36 Chapter 4 Results 39 4.1 Overall Frequency of Hedging Devices 39 4.2 Distributional Patterns across Grammatical Categories 42 4.2.1 Hedging in the Use of Modal Verbs 43 4.2.2 Hedging in the Use of Lexical Verbs 47 4.2.3 Hedging in the Use of Adverbials, Nouns, and Adjectives 49 4.3 Distributional Patterns across Proficiency Levels 54 4.4 The Lexical Pairs and EFL Language Proficiency 59 4.5 Hedging as a Stylistic Feature in EFL Student Writings 65 Chapter 5 Discussions 69 5.1 Hedging Patterns of NS and Korean Learners 69 5.2 The Impact of English Proficiency on Hedging 71 5.3 The Stylistic Features of Hedging in Korean Learners 75 Chapter 6 Conclusions and Implications 80 6.1 Implications for EFL Writing Assessment 81 6.2 Implications for EFL Teaching 83 References 88 APPENDIX A 109 APPENDIX B 113 국문초록 114Maste

중국의 부상이 멕시코 수출성장에 미치는 영향 분석

학위논문 (석사)-- 서울대학교 국제대학원 : 국제학과, 2015. 2. 김종섭.The impact of the emergence of China on Latin American states has intrigued many researchers. Mexico, among others, has the most similar export structure to that of Chinas compared to other Latin American countries and, at the same time, suffered a downfall in manufacturing industries, especially in maquiladora industries. Given this background, the aim of this study is to find out whether there has been a change in the competitive composition between China and Mexico in recent years (2000-2013) and to identify which Mexican industries have been affected by Chinese exports using Weighted Least Squares regression method and Revealed Comparative Advantage index. The results indicate that there has been a negative China impact on Mexican textile industries and positive China impact on medium-tech and high-tech machinery manufacturing industries both in short term and long term. In other words, China still has a high level of comparative advantage in textile industries, which led Mexican exports to suffer in those fields until recent years. Meanwhile, Mexican exports on medium-tech and high-tech machinery manufacturing industries are enhancing its competitiveness. To explain such result, it is more likely that both countries are on their way of reinforcing comparative advantages and expanding market than that Chinese export growth has derived Mexican export growth.1. Introduction 1.1 The Emergence of China 1.2 China and Mexico: Complementary or Competitive Partner? 1.3 Research question 2. Literature Review 2.1 Non-empirical Analysis 2.2 Empirical Analysis 3. Analytical Framework 3.1 Methodology 3.2 Hypothesis 4. Empirical Analysis 4.1 Regression results 4.2 Further Analysis 5. Conclusion and Policy Implication References Appendix Abstract (Korean)Maste

외부 디스크 파티션 이용과 I/O 감소를 통한 Defragmentation 성능 개선

학위논문 (석사)-- 서울대학교 대학원 : 전기. 컴퓨터공학부, 2011.2. 엄현상.Maste

A Study on Chinese Ditransitive Construction: A View from Construction Grammar

학위논문 (석사)-- 서울대학교 대학원 : 중어중문학과, 2012. 8. 이강재.이중타동구문은 논항구조 구문(argument structure construction)의 하나로서 동작주(agent), 피동작주(patient), 수용자(recipient)의 세 논항을 필요로 한다. 지금까지 중국어 이중타동구문에 대한 연구는 주로 동사 뒤에 두 개의 명사성 성분이 오는 이중목적어라는 통사적 관점에서 다루어졌고, 대부분 이중목적어문에 사용되는 동사를 분류하거나 간접 목적어와 직접 목적어 간의 통사⋅의미 관계를 분석하는 경우가 많았다. 이에 따라 본 연구는 Goldberg(1995)의 구문문법 이론을 통해 중국어 이중타동구문의 전체적인 특징을 조망하고, 나아가 동사와 별개로 구문 자체가 지닌 독립적인 고유한 의미를 고찰하고자 하였다. 2장에서는 구문문법 이론에 대한 소개를 다루었다. 먼저 이 이론의 토대가 되는 Fillmore(1982)의 틀 의미론과 Lakoff(1987)의 이상적 인지모델(ICM), 그리고 Langacker(1987)의 바탕(Base) 개념을 언급하였으며, Goldberg(1995)가 서술한 구문의 개념과 정의도 살펴보았다. 또한 이중타동구문이 각 문장 성분의 합으로 이루어지는 것이 아니라 동사의 참여자역과 구문의 논항역이 일대일로 대응하는 일련의 융합관계를 통해 구성되는 원리를 설명하였다. 3장에서는 중국어 이중타동구문이 나타내는 수여 의미와 획득 의미의 개념을 정의하고 구문의 중심의미로서의 적합성을 살펴보았다. 또한 중국어 모어 화자를 대상으로 한 인지 실험 결과를 통해서 중국인들은 수여 의미와 획득 의미를 독립적인 의미로 사용하고 있음을 알 수 있었다. 이를 토대로 본고는 중국어 이중타동구문의 중심 의미를 양방향으로의 성공적인 전달(a successful bidirectional transfer)이라고 주장하였다. 4장에서는 중국어 이중타동구문의 중심 의미에서 예시 연결(instance links)된 수여 구문과 획득 구문이 다의성 연결(polysemy links)을 통해 다양한 의미로 확장되는 과정을 살펴보았다. 이를 위해 孟琮(1999) 《汉语动词用法词典》의 1223개 동사 중에서 이중타동구문을 구성하는 동사 175개를 추출하여 이 동사들이 구성하는 중국어 이중타동구문의 다양한 의미들을 분류하였다. 그 결과, 수여 구문은 동작주가 수용자에게 정보를 전달하거나 허가나 동의 혹은 호칭을 전달하는 의미로 확장이 이루어지며, 획득 구문은 동작주가 수용자에게 피해를 입게 하는 의미와 동작주가 수용자에게 대가를 지불하거나 상호간의 동의를 바탕으로 수용자에게서 피동작주를 전달받는 의미, 그리고 요청을 통해 수용자에게서 피동작주를 얻길 바라는 의미로 확장이 이루어짐을 확인할 수 있었다. 결론에서는 본 논의의 결과와 함께 연구의 성과와 한계를 지적하고 앞으로의 과제를 제시하였다.The ditransitive construction, one of the argument structure constructions, has three arguments - agent, recipient, and patient. Earlier studies on Chinese ditransitives were conducted at a syntactic level which researched double object whose verb is followed by two noun properties. And many of them focused on classifying the verbs in ditransitive sentences or analyzing the syntactic and semantic relationships between direct and indirect objects. The present thesis explores the overall characteristics of the Chinese ditransitive construction and further investigates the meaning of constructions, independently of that of verbs, within the framework of the Construction Grammar (Goldberg 1995). The Construction Grammar is introduced in chapter 2. First, the theoretical foundations are presented: the Frame Semantics (Fillmore 1982), the Idealized Cognitive Model (Lakoff 1987), and the concept of Base (Langacker 1987). The concept of construction described by Goldberg and its definition are reviewed next. Following that, the principle is explained that a ditransitive construction is not just a sum of sentence constituents but a fusion of one-to-one correspondence of the participant in the verb and the argument. In Chapter 3, the concepts of giving and taking in Chinese ditransitives are defined and whether they are appropriate as the central senses of the constructions is studied. The cognitive test for Chinese native speakers showed that Chinese recognize and use the meanings of giving and taking independently. Based on this result, the present study argues that the central sense of Chinese ditransitives as a successful bidirectional transfer. In Chapter 4 is researched how the constructions of giving and taking which are instance linked from the central sense of Chinese ditransitives, are extended to have various meanings through polysemy links. I collected 175 verbs among the total of 1223 from 《Hanyu dongci yongfa cidian》(Chinese Verb Usage Dictionary) of Meng Cong(1999) and classified the Chinese ditransitive constructions into different meanings according to the verbs. Based on the findings, the giving constructions are extended to the meanings of delivering information, giving permission, and expressing agreement to the recipient or designating him or her. On the other hand, the taking shows the meaning extension of causing the recipient harm, getting something from him or her by paying the price or on a consensus basis, and hoping to get it by request. In conclusion, the result of this study is summed up with its contributions and limitations. Finally, the suggestions for further research are provided at the end of the paper.【국문초록】 ⅰ 1. 서론 1 1.1 문제 제기 및 연구목적 1 1.2 연구범위 및 방법 4 1.3 선행연구 검토 6 1.3.1 동사의 분류에 관한 연구 7 1.3.2 구문의미에 관한 연구 9 1.3.3 개사 구문의 변환관계에 관한 연구 10 2. 구문문법의 기본 개념 12 2.1 이론의 토대: 틀 의미론적 의미항목 12 2.1.1 Fillmore(1982)의 틀 의미론(Frame Semantics) 12 2.1.2 Lakoff(1987)의 이상적 인지모델(ICM)과 Langacker(1987)의 바탕(Base) 개념 13 2.2 구문의 개념 14 2.3 동사와 구문의 융합 16 3. 중국어 이중타동구문의 중심 의미 21 3.1 상반된 주장 24 3.1.1 수여 의미 25 3.1.2 획득 의미 26 3.2 인지실험 분석 27 3.3 소결 31 4. 중국어 이중타동구문의 확장 35 4.1 동사에 따른 중국어 이중타동구문의 의미 분류 35 4.2 수여 의미의 확장 38 4.3 획득 의미의 확장 43 4.4 소결 50 5. 결론 52 【참고문헌】 54 【부 록】 57 【Abstract】 64Maste

Mutation characterization of ATP7B gene in Korean patient with Wilson Disease

의과학과/석사[한글]ATP7B 유전자의 돌연변이로 P형 ATPase의 결함이 생겨 간과 뇌에 구리가 축적되는 윌슨병은 전 세계적으로 3-10만 명에 한 명 꼴로 발생되는 상염색체 열성 유전질환이다. 본 연구에서는 우리나라 윌슨병 환자들에서ATP7B 유전자의 돌연변이를 검색하고 이를 통해 한국인 윌슨병 환자에서의 분자유전학적 기전의 특성을 알아보고자 하였다. 17명의 환자를 대상으로 혈액으로부터 phenol chloroform 추출법으로 DNA를 분리하였으며 21개 exon 및 exon-intron border를 PCR direct sequencing 방법을 이용하여 분석하였다. 17명의 환자에서 10개의 돌연변이를 발견하였다. 이 중 7개 돌연변이 Arg778Leu, Ala874Val, Thr1029Ile, Val1216Met, Asn1270Ser, Leu1083Phe, c.2697_2723del27bp 는 기존에 보고된 돌연변이이며 3개 돌연변이는 Gln717Term, Lys1010Glu, IVS13+5G>C 는 novel mutation 이다. 또한 9개 polymorphism 을 발견하였다. Arg778Leu 돌연변이는 대립유전자 빈도 50%로 가장 흔한 돌연변이이며 Arg778Leu (50%), Asn1270Ser (9%), Ala874Val (6%) 은 한국인 환자에서 가장 흔히 발견되는 돌연변이이다. missense mutation은 10개의 돌연변이 중 7개로 우세한 돌연변이 type 이다. ATP7B 유전자의 돌연변이 호발부위는 exon 8-18 로 본 연구에서는 exon 8, 11, 13, 14, 15, 17, 18 에서 돌연변이가 발견됐다. 대부분 윌슨병 환자에서 돌연변이 type이나 호발부위는 비슷한 특징을 나타냈고, Arg778Leu의 대립유전자 빈도와 주요한 3개의 돌연변이는 한국인 환자만의 특징이며 이를 통해 분자유전학적 진단에 있어 신속한 조기 진단에 많은 도움을 줄 것이며, 한국인만의 돌연변이 database 구축에 활용 될 수 있을 것이다. [영문]Wilson disease, an autosomal recessive disorder of copper transport, is characterized by accumulation of excessive copper in the liver and brain. It occur one in 30,000-100,000 individuals in most populations. The gene for Wilson disease, ATP7B, is located on chromosome 13q14.3-q21.1. It produces a copper transporting P type ATPase. Mutation spectrum of the ATP7B gene was investigated in this study to characterize molecular pathogenesis of the disease in Korean patients. The 21 exons and exon-intron borders were analyzed by PCR direct sequencing in 17 patients. Ten different mutations were identified. Seven of those have been previously described: Arg778Leu, Ala874Val, Thr1029Ile, Val1216Met, Asn1270Ser, Leu1083Phe, c.2697_2723del27bp. Three among ten mutations were novel: Gln717Term, Lys1010Glu, IVS13+5G>C. Nine polymorphisms were found in the coding region. The Arg778Leu mutation is the most common mutation in Korean patients with allele frequency of 50%. Arg778Leu (50%), Asn1270Ser (9%), Ala874Val (6%), were three major mutations in Korean patients with Wilson disease. Seven mutations are missense mutation. Mutation hot spot region is exon 8-18. In this study, all pathologic mutations were identified in exons 8, 11, 13, 14, 15, 17 and 18. These findings can be helpful for molecular diagnosis of the disease and better understanding of molecular mechanisms in Korean patient with Wilson disease.prohibitio