프레임과 페데스탈에 관한 고찰 및 작업

학위논문(석사) -- 서울대학교대학원 : 미술대학 조소과, 2021.8. 오귀원.이 글은 내가 2018년 초에서 2019년 말까지 행한 작업을 중심으로 그 저변을 밝히고, 관련 연구 사례를 정리하는 한편, 작업의 과정 을 기록하는 데 의의를 두고 작성된 이야기이다. 프레임과 페데스 탈은 내 작업 속에 혼잡하게 얽혀있는 다양한 소재들을 일관되게 묶어주는 틀이기도 하고, 나로 하여금 미술사, 그리고 오늘의 미술 을 환기된 시선으로 재고해 보도록 한 촉매제이기도 하다. 프레임과 페데스탈에 관한 선행연구 조사는 대부분 2020년, 작업 을 진행한 뒤에 이루어졌다. 의식의 흐름에 맡긴 채 내 신변과 일 상에 집중하며 시도한 작업을 수습하는 과정이 되었다. 이야기의 전반부는 프레임에 관한 다양한 연구와 해석에 이어 프레임을 다 룬 작가들의 사례, 그리고 페데스탈에 관한 고찰로 구성했다. 작업 과정과 경험담은 후반부에서 다루었으며, 오늘날 작업하는 일에 관한 생각들로 이야기를 마무리했다. 20세기 이후, 미술작품에서 프레임과 페데스탈이 생략되기 시작하 면서, 미술의 장은 급진적인 확장을 거듭해온 것으로 보인다. 하지 만 오늘날 작업을 지속하는 방법을 모색하는 내게는, 더 이상의 양식적 확장이 가능한 것인지, 의미가 있는 것인지 의문스럽다. 순 환적 의식으로 역사를 바라볼 때, 과거의 요소들은 새로운 의미와 가치로 우리에게 다가올 수 있다.This is a story about the background, related cases of research, and the process surrounding my work from early 2018 to late 2019. Frames and pedestals serve as a binder that tie the clutter of various ingredients present in my work, and a catalyst for a refreshed perspective on Art history and the Art of today. The study on existing research materials on frames and pedestals began after the works were completed, mostly in 2020. This provided an opportunity to sort through my work, which reflect my stream of consciousness grounded in my surroundings and daily life. The first half of the story consists of a brief overview of the various research and interpretations regarding frames, followed by some examples of related works by artists, and a contemplation on pedestals. The recounting of my work process and experience comes in the second half, and the story concludes with reflections on Art-making today. Since the 20th century, beginning with the omission of frames and pedestals in the work of Art, the field of Art seems to have experienced a series of radical expansions. As an artist seeking ways to sustain his practice today however, the prospect and efficacy of further expansions are in question. Employing a cyclical perspective on history, elements of the past can be examined with a renewed appreciation and significance today.제 1 장 서론 1 제 2 장 프레임(frames)과 페데스탈(pedestals) 4 제 1 절 프레이머(framers), 딜러(dealers), 미술사가 6 제 2 절 작가 9 제 3 절 페데스탈(pedestals) 13 제 3 장 작품설명 19 제 1 절 “When in Rome" 19 제 2 절 "When in Doubt" 22 제 3 절 "19-S" 24 제 4 절 "19-W" 27 제 5 절 재연(reprise) 29 제 4 장 결론 34 참고문헌 36 Abstract 39석

Study on the internal structure of ferroelectric Hf1-xZrxO2 thin film systems

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2018. 2. 황철성.Ferroelectric (FE) property of HfO2 thin films was first reported in 2011 NaMLab in Dresden, Germany, which had a fluorite structure, doped with a few amounts of Si. It was a very intriguing issue on the FE community because the fluorite-type film has only ~ 10 nm thickness, whereas the conventional perovskite type ferroelectrics have > 100 nm thickness. It has merit for fabrication of 3-dimensional structure due to its small thickness. Also, the band gap of the HfO2 thin film is 5.5 eV which is high enough to prevent leakage currents flowing through devices. Having titanium nitride as a metal electrode, combined with an excellent compatibility with Si, HfO2 as a thin film could be the representative industrial-friendly materials for the adoption of memory production technology. It has been widely accepted that the emergence of unexpected ferroelectricity in HfO2 thin films is due to the formation of non-centrosymmetric orthorhombic Pca21 phase. However, it still lacks researches on the emergence of ferroelectricity in this material systems. Therefore, this dissertation aims to resolve the ambiguity of the origin of the emergence of ferroelectricity in thin films through researches on the internal structure of the FE HfO2 thin films. For its robust ferroelectricity, many dopants were induced. (Si, Zr, Y, Al, Gd, Sr, La, etc.) Among these dopants, Zr doped HfO2 has its wide composition range for emerging various electrical characteristics and lower processing temperature for crystallization of films. Therefore, Hf1-xZrxO2 thin films are up-and-coming FE materials for analyzing the mechanism of emerging ferroelectricity. As the first step, the degradation of the FE properties of atomic layer deposited Hf0.5Zr0.5O2 films with increasing thickness was examined. When the thickness of the film increases over 20 nm, the FE properties of the films start to degrade whereas the 10 nm-thick film shows robust FE properties in previous reports. The origin of the degradation was elucidated by phase transition of non-FE monoclinic phase. According to general thin film growth theory, meanwhile, the grain size of the film increases with increasing film thickness. The grain size is the critical factor to get FE properties of Hf0.5Zr0.5O2 films because the surface energy and volumetric energy are affected by the grain size. Therefore, control of the grain size of films is key point to interrupt degradation of FE properties despite of increasing film thickness. In this dissertation, the grain size is successfully controlled by inserting 1nm-thick Al2O3 interlayer at the middle position of the thickness of the FE film. The Al2O3 interlayer could hinder the continual growth of Hf0.5Zr0.5O2 films, and the resulting decrease of grain size prevented the formation of the non-FE monoclinic phase. The Al2O3 interlayer also principally decreased the leakage current of the Hf0.5Zr0.5O2 films. As the next step, a wake-up effect on the FE Hf0.5Zr0.5O2 films was examined which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of fatigue effect. In this work, the wakeup effect from the Hf0.5Zr0.5O2 was carefully examined by the pulse-switching experiment. At the pristine state, the Hf0.5Zr0.5O2 film mostly showed the FE-like behavior with a small contribution of antiferroelectric(AFE)-like distortion, which could be ascribed to the involvement of AFE phase. The field cycling of only 100 cycles almost wholly transformed the AFE phase into FE phase by depinning the pinned domains. The influence of field cycling on the interfacial layer was also examined through the pulse-switching experiments. In addition to that, the broken FE hysteresis loops achieved from a Hf0.4Zr0.6O2 film was interpreted based on the first order phase transition theory. The two-step polarization switching, which was expected from the theory, could be observed by dynamic pulse switching measurement. The variations in the interfacial capacitance values along with switching time and number of switching cycles could also be estimated from the pulse switching test. Being different from the one-step polarization switching in other FE films, two-step polarization switching produced two slanted plateau regions where the estimated interfacial capacitance values were different from each other. This could be understood based on the quantitative model of the two-step polarization switching with the involvement of an intermediate nonpolar phase. The Hf0.4Zr0.6O2 film changed from AFE-like to FE-like with increasing number of electric field cycling, which could be induced by the field driven phase change. Finally, this thesis presents a new strategy for extending conventional scaling trend in dynamic random access memory (DRAM) by utilizing newly found morphotropic phase boundary (MPB) of solid solution of the HfO2-ZrO2 system. For the purpose, the schematic phase diagram of HZO films with various thickness and Hf:Zr ratio was presented based on the previous works, and the MPB of tetragonal and orthorhombic phase for an abnormal increase in dielectric constant (r) was found. From the C-V characterizations, the extraordinary r values could be observed in the MPB, and it could be confirmed that the composition of films changes with changing film thickness. The Zr contents for MPB decreased with decreasing film thickness owing to the relative decrease of the free energy of o-phase compared to that of t-phase. The minimum tox of 0.59nm could be achieved for 8.1 nm-thick Hf0.5Zr0.5O2 films.1. Introduction 1 1.1. Overview and Issues on ferroelectrics 1 1.2. Objective and Chapter Overview 6 1.3. References 8 2. Literature 10 2.1. Conventional FE materials 10 2.2. HfO2 based FE materials 13 2. 2. 1. Identification of FE phase 13 2. 2. 2. The effect of film thickness and grain size 16 2. 2. 3. The effects of asymmetric stress 22 2. 2. 4. The effect of TiN capping and annealing 26 2. 2. 5. The effects of dopants 31 2.3. References 38 3. Grain size engineering for ferroelectric Hf0.5Zr0.5O2 films by an insertion of Al2O3 interlayer [1] 44 3.1. Introduction 44 3.2. Experimental 48 3.3. Results and Discussions 50 3.4. Conclusion 69 3.5. References 70 4. A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2 films by pulse-switching measurement [2] 73 4.1. Introduction 73 4.2. Experimental 77 4.3. Results and Discussions 79 4.4. Conclusion 101 4.5. References 102 5. Two-step polarization switching mediated by nonpolar intermediate phase in Hf0.4Zr0.6O2 thin films [3] 105 5.1. Introduction 105 5.2. Experimental 110 5.3. Results and Discussions 112 5. 3. 1. Theoretical model for phase transitions 112 5. 3. 2. Pulse switching measurement for dynamic evolution of polar and non-polar phases 122 5.4. Conclusion 143 5.5. References 145 6. Hf1-xZrxO2 films for capacitive layers in dynamic random access memory [4] 149 6.1. Introduction 149 6.2. Experimental 154 6.3. Results and Discussions 155 6.4. Conclusions 168 6.5. References 169 7. Conclusion 172 Curriculum Vitae 176 List of publications 179 Abstract (in Korean) 201Docto

- 일선관료제 이론을 중심으로 -

학위논문(석사) -- 서울대학교대학원 : 행정대학원 공기업정책학과, 2023. 8. 엄석진.일선관료제 이론은 일선관료들이 일반 시민과 직접 대면하며 공공정책의 편익 처분 및 공공재 할당 관련 업무를 수행한다. 일반 시민은 정부의 구성원인 공무원과의 대면을 통해 공공서비스를 제공받고 정부에 대한 만족도를 평가하며, 이러한 만족도는 행정의 한 지표라고 할 수 있다. 실제로 일반 시민들이 정부에 대하여 가지는 인상의 대부분은 일선에서 근무하는 일선관료에 의해 형성된다. 기존 연구는 공무원에 한정된 경향이 있어 일선관료의 범위를 공공기관의 일선근무자로 확대하였다. 실제로 공공기관의 일선근무자는 일반시민과 대면하며, 상당한 재량을 가지고 공공정책의 편익 처분 등의 업무를 수행하고 있으므로 일선관료제 이론을 적용이 가능한 것으로 보았다. 본 연구는 일선관료제 이론의 관점에서 공공기관 일선근무자의 고객대응 유형에 영향을 주는 요인이 무엇인지 살펴보고자 하였다. 일선관료제 이론을 주창한 Ripsky는 일선관료들은 제한된 자원으로 인해 개별 사건 처리에 어려움을 겪는다고 지적하였다. 이러한 상황하에서 일선관료는 효율적 업무처리를 위해 다양한 전략을 도입한다고 보았는데, 이러한 전략에는 루틴 설정, 고객 분류, 규칙 개발 등이 포함된다. Ripsky의 일선관료제 이론을 기반으로 공공기관 일선근무자의 고객대응 유형을 결정하는 요인이 무엇인지 분석하기 위해 기존 연구들을 검토하였다. 이를 바탕으로 고객대응유형을 종속변수로 하여 고객지향적 대응과 관료지향적 대응으로 분류하였다. 고객지향적 대응은 추가시간 투입, 우선권 설정, 시간관리로 세분하였으며, 관료지향적 대응은 루틴화, 할당관행, 고객공격이라는 세부항목을 설정하였다. 이러한 대응유형에 영향을 미치는 독립변수를 크게 개인요인과 직무요인으로 구분하여 분석하였다. 개인요인은 고정관념, 자기효능감, 전문가주의를 설정하였으며, 직무요인은 목표모호성, 재량권행사, 직무순환을 설정하였다. 이렇게 설정된 변수들의 측정을 위해 경기주택도시공사 소속 직원 중 보상 및 주거복지업무 수행자 163명을 대상으로 설문조사를 배포하여, 총 109명의 유효한 설문지를 받아 분석에 활용하였다. 설문 문항을 바탕으로 응답자의 기초통계 및 설문 문항에 대한 신뢰도 분석을 실시하였다. 공공기관 일선근무자의 고객대응유형 결정요인에 대한 가설을 설정하고 각 가설에 대해 이분형 로지스틱 회귀분석을 실시하였다. 결과가 미흡한 부분에 대해서는 면접조사를 실시하여 양적조사의 한계를 극복하고자 하였다. 본 연구의 분석결과를 정리하면 다음과 같다. 첫째, 고정관념은 고객지향적 대응에 음(-)의 영향을 미치는 것으로 나타났으나, 통계적으로 유의미하지 않았다. 둘째, 자기효능감은 고객지향적 대응에 양(+)의 영향을 미치는 것으로 나타났으나, 통계적으로 유의미하지 않았다. 셋째, 전문가주의는 고객지향적 대응에 양(+)의 영향을 미친다는 결과를 얻었다. 넷째, 목표모호성은 고객지향적 대응에 음(-)의 영향을 미치는 것으로 나타났으나, 통계적으로 유의미하지 않았다. 다섯째, 재량권행사는 설정한 가설과는 달리 고객지향적 대응에 음(-)의 영향을 미치는 것으로 나타났으나, 통계적으로 유의미하지 않았다. 마지막으로 직무순환은 고객지향적 대응에 음(-)의 영향을 미치는 것으로 나타났으나, 통계적으로 유의미하지 않았다. 통계적 유의성이 미흡한 일정 독립변수를 대상으로 추가적인 면접조사를 실시하였다. 그 결과 고정관념이 일선 현장에서 고객지향적 대응에 부정적 영향을 미친다는 것을 확인할 수 있었다. 또한 일선근무자는 재량권을 스스로 축소함에 따라 고객지향적 대응에 소극적이라는 결과도 얻을 수 있었다. 직무순환에 대해서는 일률적인 순환보직을 채택하기보다 직무 특성을 고려한 순환보직 설계가 필요하다는 결과를 얻었다. 본 연구의 시사점은 다음과 같다. 첫째, 일선근무자의 전문성 강화를 위한 지원 중 직무교육의 중요성이 부각된다. 직무교육은 일선근무자의 개개인 수준에 맞게 정기적으로 실시되어야 한다. 둘째, 직무순환 제도에 대한 재설계가 필요하다. 직무순환제도는 직종별, 직무별 특성을 고려하고 직원들이 장기적인 관점에서 스스로 자기개발계획을 수립할 수 있도록 설계가 되어야 한다.The theory of Street-Level bureaucrats suggests that Street-Level bureaucrats directly face and interact with the general public to carry out tasks related to the allocation of public policy benefits and public goods. The general public receives public services through face-to-face encounters with government officials, who are members of the government, and evaluates their satisfaction with the government. This satisfaction can be considered an indicator of administrative performance. In reality, the impressions that the general public has of the government are largely formed by Street-Level bureaucrats who work on the front lines. Existing research has tended to focus on civil servants, leading to an expansion of the scope of Street-Level bureaucrats to include Street-Level workers in public institutions. As these Street-Level public workers directly face the general public and exercise considerable discretion in tasks related to the allocation of public policy benefits, the application of the theory of Street-Level bureaucrats appears feasible. This study aims to examine the factors influencing the customer response types of Street-Level public workers from the perspective of the theory of Street-Level bureaucrats. Ripsky, who advocates the theory of Street-Level bureaucrats, points out that Street-Level bureaucrats face difficulties in handling individual cases due to limited resources. In such situations, Street-Level bureaucrats adopt various strategies for efficient task processing, including routine setting, customer classification, and rule development. Based on Ripsky's theory of Street-Level bureaucrats, this study categorizes customer response types as customer-oriented responses and bureaucracy-oriented responses and analyzes the factors influencing these response types by reviewing existing studies. Customer-oriented responses are further divided into subcategories such as additional time input, priority setting, and time management, while bureaucracy-oriented responses include subcategories such as routinization, allocation practices, and customer attacks. The independent variables affecting these response types are divided into personal factors and job-related factors for analysis. Personal factors include fixed ideas, self-efficacy, and professionalism, while job-related factors include goal ambiguity, discretionary power exercise, and job rotation. To measure these variables, a survey was distributed to 163 employees of the Gyeonggi Housing and Urban Development Corporation, who were engaged in compensation and residential welfare tasks, and a total of 109 valid questionnaires were utilized for analysis. Basic statistics and reliability analysis of the questionnaire items were conducted based on the survey responses. Hypotheses regarding the factors determining Street-Level public workers' customer response types were established, and binary logistic regression analysis was conducted for each hypothesis. Additional interviews were conducted for parts where the results were insufficient to overcome the limitations of quantitative research. The summarized results of this study are as follows: 1. Fixed ideas were found to have a negative impact on customer-oriented responses, but statistically not significant. 2. Self-efficacy was found to have a positive impact on customer-oriented responses, but statistically not significant. 3. Professionalism was found to have a positive impact on customer-oriented responses and was statistically significant. 4. Goal ambiguity was found to have a negative impact on customer-oriented responses, but statistically not significant. 5. Discretionary power exercise was found to have a negative impact on customer-oriented responses, contrary to the hypothesis, but statistically not significant. 6. Job rotation was found to have a negative impact on customer-oriented responses, but statistically not significant. For certain independent variables with insufficient statistical significance, additional interviews were conducted. As a result, it was confirmed that fixed ideas negatively influence customer-oriented responses in Street-Level settings. Additionally, Street-Level workers' reduced discretion leads to a passive customer-oriented response. Regarding job rotation, the results suggested the need for job rotation design considering job characteristics rather than adopting a uniform rotation policy. The implications of this study are as follows: 1. The importance of job education is emphasized as support for enhancing Street-Level workers' expertise. Job education should be conducted regularly, tailored to the individual level of Street-Level workers. 2. A redesign of the job rotation system is necessary. The job rotation system should consider the characteristics of job types and positions, enabling employees to develop self-development plans from a long-term perspective.목 차 제 1 장 서론 1 제 1 절 연구배경 및 목적 1 제 2 절 연구대상과 방법 3 1. 연구의 대상과 범위 3 2. 연구의 방법 4 제 2 장 이론적 배경과 선행연구 6 제 1 절 이론적 배경 6 1. 일선관료제 이론 6 2. 고객 대응방식 12 제 2 절 선행연구 검토 21 1. 일선관료제이론 관련연구 21 2. 공공기관 고객 대응방식 관련연구 23 3. 비판적 검토 24 제 3 장 연구설계 26 제 1 절 연구가설 및 분석틀 26 1. 분석틀 26 2. 연구가설 27 제 2 절 변수설정 및 측정도구 31 1. 독립변수 31 2. 종속변수 35 3. 통제변수 40 제 3 절 분석방법 40 1. 연구대상 범위 40 2. 자료의 수집 및 분석방법 42 제 4 장 분석 결과 44 제 1 절 기초통계 분석 44 1. 인구통계적 특성 분석 44 2. 통계량 분석 46 3. 상관관계 분석 51 제 2 절 가설의 검증 51 1. 측정문항 신뢰도 검증 51 2. 요인분석(CFA) 결과 56 3. 로지스틱 회귀분석 결과 59 4. 가설검증 결과 63 제 3 절 결과 분석 64 1. 결과 요약 64 2. 결과 논의 65 제 5 장 결론 68 제 1 절 연구결과 요약 및 시사점 68 1. 연구결과 요약 68 2. 연구의 시사점 68 제 2 절 연구의 한계 69 참고문헌 71 부록(설문지) 73석

Automatic speculative DOALL for clusters

1

Single-stranded DNA binding protein 2 expression is associated with patient survival in hepatocellular carcinoma

BackgroundSSBP2, single-stranded DNA binding protein 2, is a subunit of the ssDNA-binding complex that is involved in the maintenance of genome stability. The majority of previous studies have suggested a tumor-suppressive role of SSBP2, which is silenced by promoter hypermethylation in several human malignancies, such as hematologic malignancies, prostate cancer, esophageal squamous cell carcinoma, ovarian cancer, and gallbladder cancer. However, an oncogenic role of SSBP2 has been suggested in glioblastoma patients. We investigated the clinicopathologic significance of SSBP2 expression in hepatocellular carcinoma.MethodsWe constructed tissue microarrays consisting of 21 normal liver parenchyma and 213 hepatocellular carcinoma tissues with corresponding adjacent non-neoplastic tissues. SSBP2 expression was investigated by immunohistochemistry, and positive expression was defined as more than 10% of the tumor cells to show nuclear staining. We then analyzed the correlations between SSBP2 expression and various clinicopathologic characteristics, and further studied the role of SSBP2 in cell growth and migration.ResultsHepatocytes were negative for SSBP2 immunohistochemistry in all normal liver samples, whereas the nuclei of normal bile duct epithelium and sinusoidal endothelium were immunoreactive. Positive immunoreactivity was found in one (0.6%) out of 180 non-neoplastic liver tissue samples adjacent to the tumor and in 16 (8.5%) out of 189 hepatocellular carcinomas. Positive SSBP2 expression was significantly correlated with tumor multifocality (P=0.027, chi-square test), high histologic grade (P=0.003, chi-square test), and frequent vascular invasion (P=0.001, chi-square test). Kaplan-Meier survival curves revealed that patients with SSBP2 expression had poor prognosis in both disease-free and overall survival (P=0.004 and P=0.026, respectively, log-rank test). SSBP2-positive tumors also had a higher Ki-67 proliferation index (P<0.001, t-test). Furthermore, downregulation of SSBP2 in the Huh7 cell line inhibited cell migration (P=0.022, t-test) with altered expression of epithelial-mesenchymal transition markers.ConclusionsThe minority of hepatocellular carcinomas expressed SSBP2 by immunohistochemistry, whereas normal hepatocytes were negative. SSBP2-positive hepatocellular carcinomas were significantly associated with aggressive phenotypes and poor clinical outcome.This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science, ICT & Future Planning) (NRF-2015R1C1A1A01056091) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1D1A1B07048798)

해양천부지층탐사를 이용한 지진활동도 조사

22othe

CFD Code Development for Open Water Performance Evaluation of a Pump-Jet Propulsor

학위논문(석사) -- 서울대학교 대학원 : 공과대학 조선해양공학과, 2024. 8. 이신형.최근 잠수함 및 어뢰의 추진 장치로 펌프젯 추진기를 적용하고자 하는 연구가 증가하고 있다. 펌프젯 추진기는 회전부인 로터와 고정부인 스테이터 그리고 이들을 감싸는 덕트로 구성된 추진기로 기존 프로펠러 추진 방식에 비해 소음 성능 및 캐비테이션 성능이 우수하다고 알려져 있다. 본 연구에서는 전산유체역학(computational fluid dynamics, CFD)을 이용하여 펌프젯 추진기의 단독성능을 추정하는 코드를 개발하였다. 펌프젯 추진기 로터의 회전운동을 모사하기 위해 단일 날개 경로 기법을 도입하였다. 단일 날개 경로 기법은 로터의 단일 날개와 그 주위 격자만을 회전시키는 기법이다. 단일 날개 경로 기법은 단일 날개 경로 기법 및 수치 기법을 검증하기 위해, KP505 프로펠러의 단독성능을 추정하였다. KP505의 단독성능 추정 결과 및 프로펠러 표면에서의 압력 분포를 통해 단일 날개 경로 기법이 회전 운동을 유효하게 모사함을 확인하였다. 선박해양플랜트연구소(KRISO)에서 설계된 펌프젯 추진기의 단독성능을 해석하였다. 펌프젯 추진기의 각 구성 요소에서 발생하는 유체력을 추정하였으며, 단독성능시험 결과 및 sliding mesh 기법의 결과와 비교하였다. 펌프젯 추진기 설계 전진비 조건에서의 펌프젯 추진기 내부의 압력 분포를 비교하고 펌프젯 추진기 후류에서 속도, 압력 및 와도 분포를 확인하였다. 주요어 : 펌프젯 추진기, 전산유체역학, 수치해석, 유체역학적 성능 학 번 : 2022-26607Recent research into the application of pumpjet propulsors as propulsion systems for submarines and torpedoes has been increasing. A pumpjet propulsor consists of a rotor (rotating part), a stator (stationary part), and a duct that encompasses both. It is known to exhibit superior noise and avitation performance compared to conventional propeller propulsion methods. This research presents a numerical investigation of the open water performance of a pumpjet propulsor. The Single Blade Passage method was employed to simulate the rotational motion of the pumpjet's rotor, effectively capturing the rotational dynamics by directly rotating the area around a single blade and its surrounding grid, this method is cost-effective. To validate this method, an analysis of the open water performance of the KP505 propeller was conducted. The results of the open water performance estimation and the pressure distribution on the propeller surface confirmed that the Single Blade Passage method effectively simulates rotational motion. The study applied this method to a pumpjet propulsor designed by KRISO. The numerical results were validated against the open water test results from the large cavitation tunnel at KRISO and sliding mesh method. Changes in the thrust and torque of the pumpjet propulsor according to the advance ratio were analyzed using SNUFOAM, an open-source CFD toolkit based on OpenFOAM. Additionally, the flow around the pumpjet propulsor was compared with previous studies and sliding mesh method. Keywords : Pumpjet propulsor, Computational Fluid Dynamics, Numerical Analysis, Hydrodynamic Performance Student Number : 2022-26607제 1 장 서 론 1 제 1 절 연구의 배경 1 제 2 절 연구 목표 및 내용 6 제 2 장 코드 개발 7 제 1 절 해석 솔버 7 제 2 절 단일 날개 경로 기법 9 제 3 장 솔버 검증 12 제 1 절 KP505 프로펠러 12 제 2 절 KP505 프로펠러 단독성능 추정 16 제 4 장 솔버 적용 19 제 1 절 펌프젯 추진기 19 제 2 절 펌프젯 추진기 단독성능 추정 25 제 3 절 펌프젯 추진기 주위 유동 해석 30 제 5 장 결 론 38석

Rifting to spreading at the Korean margin

While diverse opening models of the East Sea (Japan Sea) have been proposed so far, the structural evolution of the eastern Korean margin has not been investigated where back-arc rifting and breakup leading to the separation of the Japan Arc from the Korean Peninsula took place. We interpreted marine seismic profiles in conjunction with swath bathymetry and magnetic data to address rifting to breakup processes at the Korean margin. Changes in rift structure are recognized between the northern and southern parts of the margin. In the northern part, rifting occurred in the Korea Plateau, a continental fragment extended and partially segmented from the Korean Peninsula, that provided a relatively broader zone of extension resulting in a number of rifts. Two distinguished rift basins (Onnuri and Bandal Basins) in the Korea Plateau are bounded by major synthetic and smaller antithetic faults, creating wide and symmetric profiles. The large-offset border fault zones of these basins have convex dip slopes and demonstrate a zig-zag arrangement along strike. In contrast, the southern margin is engraved along its length with a single narrow rift basin (Hupo Basin) that is an elongated asymmetric half-graben. The rifting architecture at the Korean margin exhibits fundamental elements comprizing a seaward succession of a rift basin and an uplifted rift flank passing into the slope. Breakup is interpreted to have occurred along the base of the slope. Rifting was primarily controlled by normal faulting resulting from extension orthogonal to the line of breakup. Although rifting involved no significant volcanism, the inception of sea floor spreading documents a pronounced volcanic phase which seems to reflect slab-induced asthenospheric upwelling as well as rift-induced convection. We suggest that structural and igneous evolution of the Korean margin can be explained by the processes occurring at the passive continental margin with magmatism intensified by asthenospheric upwelling2