TRANSIENT SIMULATION OF ELASTIC WAVES USING MIXED PERFECTLY-MATCHED-LAYERS

Kim, Bo Young 홍익대학교 대학원 2016 국내석사

The author wishes to express her deepest gratitude and appreciation to Dr. Kang, Jun Won for his guidance and support during author's pursuit of the Master Degree. The author also wishes to acknowledge the invaluable comments and suggestions provided by the members of his reading committee, Drs. Yoon, Chongyul and Yoon, Soon-Jong. Special thanks go to her colleagues in structural laboratory, Ms. Kim, Sun-Hee, Mr. Lee, Hong-Gyu, Mr. Yoo, Jong-Ho, Mr. Lim, Hyun-Kyu, Mr. Pak, Hong-rak, and Mr. Joh, Namho. Without their invaluable assistance, this thesis could not have been completed. The author must express her deepest thanks to her parents, Kim, Eui-Soo, and Yoon, Geumsun, her older sister, Kim, Hye-Young, and her younger brother, Kim, Young-Wook. Additionally, the author wishes to express her deepest thanks to her friends Shin, Sunmi, Lim, Eunhee, Kim, Gunjo, Dai, WangQiu, Choi, Youn-Young, and the rest of people who give an encouragement and affection to the author. 무한 또는 반무한 영역에서 탄성파의 전파 거동을 해석하기 위해서는 반사파의 영향을 제거할 수 있는 수치적 기법이 필요하다. 이를 위해 이 논문에서는 해석 대상 유한영역의 경계에 파동흡수 경계조건인 Perfectly-Matched-Layers (PML)을 도입하여 2차원 및 3차원 반무한 영역에서 탄성파의 전파거동을 계산하는 수치적 기법을 제시하였다. 복소좌표변환과 푸리에 변환 기법을 적용하여 주파수 영역에서 PML을 경계로 하는 탄성거동을 하는 파동방정식을 유도하고, 시간 영역으로 역푸리에 변환 기법을 적용하므로서 변위(와 응력()이 혼합된 편미분 방정식 시스템으로 표현할 수 있다. 유도한 변분식에 Galerkin법을 기반으로 혼합유한요소법을 적용하여 선형운동방정식 시스템을 얻을 수 있으며, 이에 대해 시간적분을 수행하여 PML을 경계로 하는 탄성영역에서 변위와 응력의 수치해를 계산할 수 있다. 제안한 PML 기법을 적용하여 2차원 및 3차원 영역에 대해 탄성파의 거동을 수치 해석한 결과, 탄성파에 대해 우수한 파동흡수 성능을 보이며 무한영역에서의 파동전파 해석에 효과적으로 적용될 수 있음을 확인하였다. 또한, 대규모 3차원 문제의 계산시간과 메모리 문제를 해결하기 위해 MPI (Message Passing Interface)를 기반으로 병렬 컴퓨팅을 수행하였다. 수치해를 계산할 때 반복해법인 GMRES (Generalized Minimal Residual)법을 사용하였으며, 병렬 프로그래밍에서 중요한 성능 척도가 되는 확장성(scalability)을 분석하였다. 이 연구는 지반-구조물 상호작용 해석, 탄성파를 이용한 구조건전성 평가 등의 적용을 목적으로 한다.

(The) Preparation and Characterization of Master-Batch for Greenhouse Films with Functional Nanoparticles

Chun, Young-Won 부경대학교 대학원 2001 국내석사

Comparison of oral microbiota in patients with medication-related osteonecrosis of the jaw through oral microbiome analysis

김헌영 Graduate School, Yonsei University 2023 국내박사

ABSTRACT Comparison of oral microbiota in patients with medication-related osteonecrosis of the jaw through oral microbiome analysis Heon-Young Kim Department of Dentistry The Graduate School, Yonsei University (Directed by Professor Young-Soo Jung) Medication-related osteonecrosis of the jaw (MRONJ), which occurs due to drugs like antiresorptive agents, was first introduced in 2003 and is one of the most severe complications reported over the past 20 years. The prevalence of MRONJ has increased due to an increase in the number of patients receiving oral or intravenous bisphosphonates, receptor activator of nuclear factors κB ligand inhibitors, or drugs with antiangiogenic effects. However, the etiology of MRONJ has not been fully understood. No disease-causing markers have been identified, and a single model that explains the macroscopic and microscopic morphological changes in MRONJ has not been possible. Recently, oral bacteria have been suggested to play an important role in the pathogenesis of MRONJ. The purpose of this study was to identify the oral microbiome in MRONJ. Fifteen patients who had confirmed MRONJ and visited the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital between 2021 and 2022 were recruited for this experiment. Samples from the affected and non-affected sides of patients diagnosed with MRONJ were collected. The composition and enumeration of the microbial community were analyzed, and diversity was compared to verity the ecological changes in groups using a next-generation sequencing-based 16S metagenomic analysis. The following results were obtained. 1. Although there was no significant difference in bacterial types between the non-affected and affected areas, we observed variations in the composition and coefficient in the microbiome analysis, which was performed at the phylum, genus, and species levels. 2. The identified microorganisms included many species known to cause periodontitis, gingival disease, and root canal infections. It can be inferred that MRONJ may occur due to various factors rather than being solely attributed to specific microorganisms. Understanding the interactions and functional aspects among these microorganisms may contribute to our comprehending of the etiology of MRONJ. 3. Addressing these limitations through larger-scale studies will further clarify the importance of oral bacteria in the pathogenesis of MRONJ and facilitate the development of effective therapeutic interventions for patients with MRONJ.

(An) effective load balancing scheme for multi-agent system

Lee, Young Joon Sungkyunkwan University 2012 국내석사

최근에, 다중 에이전트 시스템은 확장성 및 유연성 있는 소프트웨어 시스템을 개발하는데 광범위하게 사용된다. 분산 시스템에서 노드들간에 작업을 분산하여 부하를 균등하게 하기위해 사용되는 로드 밸런싱 기법은 중요한 이슈들 중에 하나이다. 반면에, 다중 에이전트 플랫폼은 시스템의 전체적인 관리를 수행하기 위한 과부하가 발생할 수 있다. 그러므로, 전체 시스템의 성능을 향상시키기 위해서 부하는 노드들 사이에 적절하게 분산되어야 한다. 본 논문에서는 다중 에이전트 플랫폼에서 과부하를 최소화 하기 위한 기법을 제안한다. 이를 위해서, 에이전트들이 실행되는 노드의 하드웨어 자원을 체크하기 위해 제안된 시스템에서는 하드웨어 자원 관리 에이전트를 사용한다. 또한 과부하를 최소화하고 자원들의 이용률을 높이기 위해서 노드들간에 동적 로드 밸런싱 기법을 사용한다. 제안되는 기법은 성능평가를 통하여 기존에 존재하는 기법에 비해 전체 시스템의 과부하 상당히 감소 시켜주는 것을 보여준다.

고령의 류마티스관절염 환자에서 급성관상동맥증후군에 대한 경피적 관상동맥중재술의 예후

Kim, Bo Young Soonchunhyang University Graduate School 2023 국내박사

ABSTRACT Outcomes of percutaneous coronary intvervention for acute coronary syndrome in elderly patients with rheumatoid arthritis Bo Young Kim, M.D. Department of Internal Medicine Graduate School of Medicine, Soonchunhyang University Asan, Korea Supervised by professor Hyun-Sook Kim, M.D., Ph.D. Objective This study aimed to evaluate the clinical outcomes of elderly patients with and without rheumatoid arthritis (RA) who were diagnosed with acute coronary syndrome and underwent percutaneous coronary intervention (PCI). Methods The Korean National Health Insurance Service claims database was used to extract data on 74,623 (14,074 with RA and 60,549 without RA) aged ≥65 years who were diagnosed with acute coronary syndrome and underwent PCI between 2008 and 2019. The primary outcome was survival between elderly patients with and without RA. The secondary outcome was survival in the RA subgroup. Results During a 10-year follow-up, the all-cause mortality rate was lower in patients with RA than that in patients without (53.7% vs. 58.3%, respectively, log-rank: p < 0.001). In the all-cause mortality RA subgroup, patients with elderly-onset RA had poor survival outcomes, whereas patients with young-onset RA have good survival outcomes compared with that in patients without RA (48.1% vs. 73.7% vs. 58.3%, respectively, log-rank: p < 0.001). The major clinical factors associated with mortality were chronic obstructive pulmonary disease, moderate-to-severe chronic kidney disease, and ST-elevation myocardial infarction diagnosis at PCI index date, in addition to the traditional cardiovascular risk factors. Conclusion Elderly patients with RA who were diagnosed with acute coronary syndrome and underwent PCI had an increased mortality risk, particularly those with elderly-onset RA than young-onset RA. Patient characteristics and clinical factors associated with the survival outcomes need to be considered during the treatment of elderly paitents with RA for a better prognosis of cardiovascular diseases.

Effect of curcumin on paclitaxel induced neuropathic pain in rats

Hwang, Boo Young 부산대학교 대학원 2015 국내박사

서론: 파클리탁셀 유발 신경병성통증 모델의 기전을 연구하고 신경병성통증에 효과를 보이는 여러 약물에 대한 많은 연구 결과가 있다. 하지만 파클리탁셀 유발 신경병성통증에 대한 커큐민의 효과와 그 기전에 대한 연구는 없다. 본 연구를 통하여 백서에 파클리탁셀 주입 후 신경병성통증 발생을 연구하고 커큐민의 진통, 예방 효과에 대하여 알아보고자 하였다. 대상 및 방법: 150-250 그람의 수컷 Sprague-Dawley 계 흰쥐 48마리를 사용하였다. 4% isoflurane으로 마취 후 이틀에 한번씩 4회 파클리탁셀(2 mg/kg i.p.)을 주입하여 신경병성통증을 유발시켰고 신경병성통증의 정도는 von Frey 필라멘트로 뒷발바닥을 자극하여 기계적 자극에 대한 반응역치를 측정하였다. 첫 번째 실험은 파클리탁셀 모델이 만들어진 후 DMSO, 커큐민 25 mg/kg, 커큐민 50 mg/kg을 각각 투여하여 반응역치를 측정하였다. 두 번 째 실험으로 파클리탁셀 모델에서 커큐민을 투여했을 때의 24시간 이내의 급성 진통 효과를 같은 방법으로 관찰하였고, 세 번째 실험을 통해 파클리탁셀과 커큐민을 같이 투여한 군과 파클리탁셀 투여 직 후 커큐민을 투여한 군의 예방적 효과를 비교하였다. 실험 종료 후 전자현미경으로 좌골신경을 관찰하고, 척수조직의 GLT-1, GLAST, 및 GFAP의 실시간 중합효소연쇄반응을 시행하였다. 결과: 파클리탁셀을 투여한 군에서 초기 21일간 반응역치가 급격히 감소하였고 모든 쥐에서 신경병성통증이 발생하였다. 파클리탁셀 유발 신경병성통증 모델이 생성된 이후 커큐민 50 mg/kg에서 진통 효과를 보였고, 신경병성통증 발생 이전 파클리탁셀과 커큐민을 동시 투여 한 군에서 신경병성통증의 발생을 예방하는 것을 알 수 있었다. 파클리탁셀 유발 신경병성통증 모델에서 GFAP mRNA의 발현이 유의하게 증가하였으며, 커큐민 투여는 GFAP의 증가를 유의하게 감소시켰다. 결론: Sprague-Dawley 쥐에서 파클리탁셀 투여 후 신경병성통증이 발생하였으며 커큐민이 그 용량과 투여시기에 따라 신경병성통증의 진통, 예방에 효과가 있을 것으로 사료되며, 척수에서 GFAP 발현을 억제하는 것이 기전의 하나로 생각된다.

The effect of thermocycling on physical properties and biocompatibility of various CAD/CAM restorative materials

김세영 Graduate school of dankook university 2023 국내박사

Statement of problem The properties of different dental computer-aided design and computer-aided manufacturing (CAD/CAM) materials can vary depending on the clinical situation. Studies on the physical properties and biocompatibility of dental restorations using various CAD/CAM materials for long-term use are lacking. Purpose The purpose of this study is to evaluate the change in physical properties and biocompatibility of CAD/CAM restorative materials after thermocycling aging. Materials and methods As CAD/CAM restorative materials, a total of 225 specimens in plate form (12.0×14.0×1.5 mm) were prepared from lithium disilicate glass ceramic (M; IPS e.max CAD), zirconia-reinforced lithium silicate glass ceramic (C; Celtra Duo), polymer-infiltrated ceramic network (E; Vita Enamic), resin-nanoceramic (S; Cerasmart), high translucency zirconia (Z; Lava Plus Zirconia). Each type was randomly divided into three subgroups (n=25; each) according to the thermal cycling procedure: (1) stored in distilled water at 37°C for 24 h (control group), (2) 10,000 cycles in distilled water at 5–55 ℃(first aged group), (3) 22,000 cycles in distilled water at 5–55℃(second aged group). The nanoindentation hardness and Young's modulus (nanoindenter), surface roughness (atomic force microscopy (AFM)), surface texture (scanning electron microscopy (FE-SEM)), and elemental concentrations (energy dispersive spectroscopy (EDS)) were evaluated. Contact angle was evaluated. The cultured human gingival fibroblasts (HGFs) morphology, proliferation and adhesion were analyzed; cell metabolic activity/viability by CCK-8 assay and ratio of live/dead cells by fluorescence microscopy. HGF’s cell adhesion ability was measured by using immunofluorescence of adhesion-related proteins. All data were submitted to the Shapiro-Wilk test to check the assumption of normality. One-way ANOVA (p =.05) with Tukey HSD post hoc test and independent samples t-tests were performed to compare the nanoindentation hardness, Young’s modulus, cell viability, F-actin intensity, Talin-1 intensity before and after thermocycling aging. Kruskal-Wallis tests with Mann-Whitney U test were performed for AFM and EDS to compare the surface roughness and composition of the materials before and after thermocycling aging. Result Nanoindentation hardness and young’s modulus of CAD/CAM materials are lower than that of ceramic materials and decreased after thermocycling aging. Among all the materials, Cerasmart exhibited the lowest values of nanoindentation hardness and elastic modulus. All materials showed altered surface microstructures and ratios of element compositions after aging except for Cerasmart. Surface roughness showed a significant increase in all materials after aging procedure, and Cerasmart exhibited the highest Ra value, while Lava Plus zirconia had the lowest Ra value. In terms of contact angle, Lava Plus zirconia had the highest value, while Vita Enamic and Cerasmart exhibited similar contact angle patterns. The cell viability of HGFs was high for all materials and showed a decrease with aging for the remaining material except for Lava Plus zirconia. Zirconia-reinforced lithium silicate exhibited significantly lower cell viability compared to other materials. With aging, there was a decrease in the immunofluorescence intensity of F-actin, except for the Vita Enamic group. Additionally, in all materials, the extent of cell spreading increased when cells were cultured for 24 hours compared to the 4-hour culture period. In terms of cell adhesion, Cerasmart, Vita Enamic, and Lava Plus Zirconia showed an increase in cell adhesion after aging. Conclusion The results of this study demonstrated the accelerated aging procedure induced the change of physical properties of CAD/CAM materials. The nanoindentation hardness and young’s modulus were decreased after thermocycling aging. The physical properties of the materials exhibited differences before and after aging. Cell viability and proliferation of the material decreased with aging except for high translucent zirconia materials. Significant differences in cell viability of HGFs on CAD/CAM materials were observed. Zirconia-reinforced lithium silicate exhibited significantly lower cell viability compared to other materials. The surface roughness increased with aging in all groups, and resin nanoceramic showed the highest roughness, while high translucent zirconia exhibited the smoothest surface among the materials. After aging, changes in the surface microstructure, composition and hydrophilicity were observed. Cell adhesion and growth on a material surface are influenced by various factors such as surface chemical composition, hydrophilicity, roughness, and topography.

Longitudinal-mode controlled lasers and application to imaging system : 레이저의 종파 모드 제어 및 이미징 시스템 응용

Young Bo Shim Hanyang University 2017 국내박사

In this thesis, control techniques of operation wavelength and longitudinal-mode of fiber laser were proposed. Various wavelength filtering techniques and single-longitudinal-mode operation techniques were investigated. A swept-source optical coherence tomography (SS-OCT) based on the longitudinal-mode controlled laser was demonstrated. In addition, to overcome previous limitation, time-multiplexed multifocal multiphoton microscopy technique based on a fiber bundle was proposed. Wavelength control technique for the laser is investigated. For control of the operation wavelength of the laser, techniques with wavelength switching, interleaving, wavelength spacing tuning, and sweeping were demonstrated. Transmission of the filtering wavelength can be switched based on a hybrid Sagnac interferometer incorporating a sampled fiber Bragg grating. In addition, a resonance peak wavelength of Sagnac interferometer based on polarization maintaining fiber can be controlled. The transmission wavelength can be interleaved by cascading the Sagnac interferometer with the sampled fiber Bragg grating. The longitudinal-mode of the fiber laser cannot be controlled sufficiently because the longitudinal-modes of the laser cavity is very dense. The transmission wavelength of the wavelength filter generally contains multi-longitudinal-modes. To suppress the multi-longitudinal mode, the performance of a sub-ring cavity was enhanced based on microfiber technique. For extremely wide free spectral range (FSR), a microfiber knot resonator (MKR) was proposed. The FSR was measured to be 365 GHz. The wavelength filtering techniques were applied to fiber lasers. A single-wavelength fiber laser was fabricated and applied for simultaneous measurement of radiation dose and strain. The multiwavelength laser was fabricated with wavelength switching, interleaving, and wavelength spacing tuning. A nonlinear polarization rotation technique was exploited for stable operation and wavelength switching. The multiwavelength laser based on polarization-differential delay line was utilized for the continuous tunable microwave filter. The swept laser based on a Fourier-domain mode-locking (FDML) was investigated. A novel single-longitudinal-mode FDML laser based on the MKR was proposed and experimentally demonstrated for the SS-OCT system. Axial resolution was 10 μm due to the wavelength swept range of 116.2 nm. The sensitivity roll-off of point-spread function was well matched with a theoretical value. In addition, a time-multiplexing multifocal multiphoton microscope based on a fiber bundle was proposed. Previous limitation was overcome by maximizing temporal separation between the multiple foci. The axial resolution was the same with a confocal microscope based on a single fiber. In addition, an illumination system for ophthalmic microscope was fabricated based on the multifocal configuration. The performance of the system was compared to the conventional system by animal test and clinical trial.

Spirits and other signs : the practice of divination in Seoul, Republic of Korea

Young U.M.I. 1980 국내박사

Appropriateness of Korean EFL Learners' Refusals via Open Role-Plays

Yoon, Hyeon-Kyeong University of seoul 2010 국내박사

Appropriateness of Korean EFL Learners' Refusals via Open Role-Plays by Hyeon-Kyeong Yoon Department of English Language and Literature Graduate School, University of Seoul Supervised by Professor Young-in Moon ABSTRACT In the field of interlanguage pragmatics (ILP), speech act performance has attracted researchers' attentions over three decades. Of the ILP research, to investigate the speech act behaviors of nonnative speakers of English (NNSs), refusals have interested many researchers. Refusals are face-threatening acts because mutual interlocutors' positive and negative faces can be threatened by refusing interlocutors' requests, invitations, offers, or suggestions. Therefore, even advanced ESL/EFL learners had difficulty in performing refusal speech acts appropriately. Since learners do not know what, how, and who to say in which situation, they are less likely to perform speech acts successfully. This stems from lack of pragmatic competence and the knowledge of sociocultural norms to target language. The purposes of the present study are to investigate the followings: first, what are the semantic formulas employed by the Korean adult EFL learners (KEFLs) when they perform refusals via open role-plays? Second, what are appropriate or inappropriate speech act behaviors of the Korean adult EFL learners identified by English native speakers (ENSs)? Third, what criteria do the English native speakers use when they rate and comment on the refusal performances by the Korean adult EFL learners? To examine the research questions, the present study adopted open role-plays to investigate KEFLs' verbal and nonverbal performances simultaneously. Since most studies adopted the written discourse completion tests (DCTs), real-like performances have rarely been examined. To collect the data, the 54 KEFL-ENS pairs were asked to verbally act out in the four given refusal situations. Over 78 percent of the KEFLs were advanced and high-intermediate level of TOEIC and the rest were intermediate. Their performances were video-taped and transcribed. The ENSs, who were 3 Americans and one British-English speaker, were then asked to rate the learners' refusal performances on a-5 Likert scale, which was from very inappropriate to very appropriate. They were further asked to comment on the appropriateness or inappropriateness of the learners' verbal and nonverbal behaviors from the ENSs' intuition. Analyzing the data, the semantic formulas the KEFLs used in the present study were direct, indirect, and adjunct strategies. In direct strategy, non-performative 'no' and negative ability were used. Of the indirect strategies, reason strategy was used most, but slightly more than regret strategy. Compared to previous studies which employed the written DCTs, avoidance or alternative strategy was the third most used. However, attempt to dissuade interlocutor strategy was preferred the third in the present study. When the interlocutor was in higher status, the KEFLs used regret strategy more than reason strategy. However, when the interlocutor was in equal status, they employed reason strategy more, which showed that Koreans were sensitive to higher social status. Most interesting finding was that the KEFLs used pause fillers a lot as adjunct strategy, which was contrast with other studies using the written DCTs. Since the participants acted out open role-plays, which made real-like situations for the KEFLs and had them speak naturally, the KEFLs used pause fillers almost half of the overall verbal performances. It was noticeable that When people speak, up to 50 percent of their speaking time may be up to pauses. Examining the appropriateness of the KEFLs' refusal performances, 10 things were considered when the ENSs judged and rated them: When the interlocutor in higher status requested a help from or invited the KEFLs, absence of gratitude, informal language use, not suggesting help, direct refusal without hesitating, nonverbal laughter, and verbosity were considered impolite. When the interlocutor in equal status requested a help from and invited the KEFLs, the reasons/excuses sounding dishonest, not suggesting help, verbosity and not showing familiarity were pointed out as inappropriateness. The appropriate and polite things the ENSs pointed out included future acceptance and suggesting alternative for invitations. Especially, one of the features of oral role-plays was nonverbal side. In the present study, most KEFLs laughed or giggled, which all the ENSs considered rude, insincere, and unprofessional, no matter how nervous the KEFLs were. Therefore, the KEFLs seemed to feel difficult when they refused the requests and invitations, especially in higher status, or sometimes they were confused with higher status and equal status. Since some of them employed the same language to the different status, this can lead to miscommunications or misunderstanding of mutual interlocutors in real situations. The overall appropriateness of the KEFLs' refusal performances was 2.9 of the 5 points. This means their responses were not rude or polite but acceptable. The mean score of the each situation was a little different. 2.9 points in situation 1, 3.3 points in situation 2, 2.6 points in situation 3, and 3.5 points in situation 4. The four ENSs rated and made comments on the KEFLs' performances by the ENSs' sociocultural norms and conversational conventions. Each ENS had their own criteria. The ENS rater 1 and 4 focused on whether the overall performances were plausible or not. Especially, they considered lame excuses very inappropriate and impolite. They considered helping others attitudes very appropriate. The ENS rater 2 and 3 weighed correct forms of address, greetings to the level of status and distance. Especially, ENS rater 3 pointed out incorrect language use. The ENSs rated 1 or 2 points at improper language use most in higher status, and bad excuses. They rated 3 points at rather complex values, such as using proper language but not plausible reasons, or using plausible reasons but improper language. They rated 4 or 5 points when the overall interactions were natural enough, and when the 10 things pointed out above kept well. However, total mean score of the KEFLs' performances was 2.9 points. This means that the English education in Korea should concentrate on four things suggested in the present study to improve cross-cultural differences as well as KEFLs' linguistic proficiency. To this, teacher training should turn its way to cultural importance, teachers should make more efforts to improve themselves, social variables such as status, and distance should be dealt, and more opportunities should be made by practicing orally. Highlighting the culture differences, teaching should focus on how and who to speak in which situations more than on how correctly to speak.