(단색수차 보정에 대한 수학적 접근

학위논문(박사)--서울대학교 대학원 :자연과학대학 수리과학부,2020. 2. 강명주.This thesis introduces efficient and effective methods for solving monochromatic aberration correction problems. The proposed methods are based on Forward-Backward proximal splitting method, which solves the optimization problem by iteratively solving two sub parts for each step: 1. gradient descent and 2. noise removal. Since the gradient descent part has high computational cost, we develop a low-cost implementation of computing aberration operator and its transpose. Then, we propose 6 different methods, which are based on 6 types of different regularization in the noise removal part. In this thesis, we perform experiments on the proposed image restoration methods. In the experiments, we use synthetic images generated by point spread functions (PSFs), which emulate the effects of monochromatic aberration in modern digital cameras.이 연구는 단색 수차 보정 문제를 풀기 위한 효율적이고 효과적인 방법들을 소개한다. 제안된 방법들은 Forward-Backward proximal splitting 방법에 기반한 것으로 이 방법은 최적화 문제를 경사하강법과 노이즈 제거의 두 문제로 나누어 반복 방법을 통해 푼다. 단색 수차 문제에 있어서 경사하강법은 큰 계산 비용을 요구하기 때문에 수차 연산자의 저비용 구현 방법을 개발한다. 이어서 6가지의 서로 다른 정칙 연산자에 기반한 노이즈 제거 방법을 적용한 영상 복원 방법을 제안한다. 이 연구에서는 제안된 영상 복원 방법들에 대한 실험을 수행한다. 실험에서는 점확산함수 (Point Spread Function)을 이용해 합성된 수차 영상을 이용하는데, 해당 점확산함수는 현대 디지털 카메라의 단색 수차 효과를 모방한 것이다.1 Introduction 1 2 Related Works 5 2.1 Approximation Methods 5 2.1.1 Methods 5 2.1.2 Methods Comparison and Conclusion 7 2.2 Basic Fourier Optics 8 2.2.1 Wavefront Optical Path Difference, W (x, y) 8 2.2.2 Pupil and Amplitude Transfer Functions 11 2.2.3 Point Spread Functions 12 2.3 Mathematical Preliminaries 14 2.3.1 Basic Properties of svcOperators 14 2.3.2 Regularizations in Inverse Problems 16 2.3.3 Convex Optimization Theory 21 3 Proposed Methods 30 3.1 Low Cost Implementation Using Small Support Assumption 31 3.1.1 Vectorization Techniques 33 3.2 Proposed Algorithm 34 3.2.1 Forward Backward Splitting Algorithm 35 3.2.2 Split Bregman Method 38 3.2.3 Algorithms 42 4 Experiments 47 4.1 Implementation Details 47 4.1.1 Generation of synthetic blurry images 47 4.2 Numerical Results 49 4.2.1 Synthetically Blurred Images 50 4.2.2 Image Restoration 52 5 Conclusion and Future Work 65 5.1 Conclusion 65 5.2 Future Work 66 Abstract (in Korean) 71Docto

Micro-computed tomographic evaluation of bone healing following dental extraction in beagle dogs treated with zoledronic acid

Dept. of Dentistry/박사Medication-related osteonecrosis of the jaws (MRONJ) is a rare but potentially severe side effect of long-term use of antiresorptive and antiangiogenic agents. However, the etiopathology of this condition is still not fully understood. In order to establish the pathogenesis of this disease, a reliable and reproducible animal model is required. The purpose of this study was to induce clinical features of MRONJ after tooth extraction in zoledronate treated beagle dogs, and analyze bone healing using micro-CT. The results are as follows; 1. In the experimental animal, extraction sites showed exposed bone with impaired wound healing at both post-extraction 1 month and 2 months. 2. Extraction sockets of the experimental animal showed significantly lower values of bone volume fraction, trabecular number, and trabecular thickness than those of the control animal at both post-extraction 1 month and 2 months. 3. Septal bone of the experimental animal showed significantly lower values of bone volume fraction than those of the control animal at both post-extraction 1 month and 2 months. 4. Cortical bone of the experimental animal showed significantly lower values of cortical area fraction, higher values of cortical porosity and average pore volume than those of the control animal at both post-extraction 1 month and 2 months. 5. In the experimental animal, new bone formation was noted outside buccal and lingual cortex at both post-extraction 1 month and 2 months. Although the sample size of this study is limited, this study introduces beagle dog as a promising large animal model for MRONJ. From this model, microarchitectural morphometric changes of bone healing after tooth extraction were evaluated. This animal model can be used for further research in the fields of MRONJ etiopathology and treatment. 약제 관련 턱뼈 괴사(Medication-related osteonecrosis of the jaw, MRONJ)는 비스포스포네이트, RANKL antibody 계열의 골흡수억제제 및 혈관신생억제제의 장기간 사용과 관련되어 드물게 발생하지만 때로는 심각하게 나타날 수 있는 합병증이다. 턱뼈에서만 특이적으로 괴사가 나타나는 이유에 대하여 다양한 가설이 제시되고 있으나 아직까지 명확한 발병 기전은 밝혀지지 않은 상태이다. MRONJ의 발병 기전을 밝히고 치료 방법을 개발하기 위해 소형 동물모델에 대한 여러 연구들이 보고되어 왔으나, 아직까지 만족할만한 대형 동물모델은 개발되지 않은 상태이다. 이번 연구에서는 비스포스포네이트가 투여된 비글견에서 발치 후 MRONJ를 유도하고, 골 치유 양상을 micro-CT를 이용하여 분석하여 다음과 같은 결과를 얻었다 1. 대조군에서는 발치 후 1개월, 2개월에서 발치와 주변의 정상적인 연조직 치유가 관찰되었으나, 실험군에서는 발치 후 1개월, 2개월에서 모두 발치와 주변의 골노출이 관찰되었다. 2. 실험군에서는 대조군에 비해 발치 후 1개월, 2개월에서 발치와의 bone volume fraction, trabecular number, 그리고 trabecular thickness가 유의하게 낮게 나타났다. 3. 실험군에서는 대조군에 비해 발치 후 1개월, 2개월에서 치간 해면골의 bone volume fraction이 유의하게 낮게 나타났다. 4. 실험군에서는 대조군에 비해 발치 후 1개월, 2개월에서 피질골의 cortical area fraction이 유의하게 낮게, cortical porosity와 average pore volume은 유의하게 높게 나타났다. 5. 실험군에서는 발치 후 1개월, 2개월에서 협설측 피질골 외측에 신생골 형성이 관찰되었다. 이번 연구를 통해 Zoledronic acid가 투여된 비글견에서 발치 후 1개월부터 임상적으로 MRONJ의 정의에 부합하는 결과를 얻을 수 있었으며, 미세구조학적으로 심하게 손상된 발치와 주변 해면골 및 피질골의 골 구조를 확인하였다. 이 모델이 MRONJ의 병태생리 규명 및 치료 개발을 위한 연구에 사용될 수 있을 것으로 평가된다.ope

Full thickness skin grafts from the groin: donor site morbidity and graft survival rate from 50 cases

OBJECTIVES: Full thickness skin grafts (FTSG) offer several advantages; they are esthetically superb, have less postoperative shrinkage, and offer minimal postoperative pain and scar formation at the donor site. As a donor site of FTSG, the groin offers a relatively large area of skin with high elasticity. The aim of this study was to evaluate FTSG from the groin for reconstruction in oral and maxillofacial surgery. MATERIALS AND METHODS: In a retrospective study, 50 patients (27 males, 23 females) who received FTSG from the groin were evaluated for their operation records, clinical photography, and medical records. RESULTS: The width of skin from the groin was distributed from 2-8 cm (mean: 5.1 cm) at the donor site, while the long axis length was distributed from 3-13 cm (mean: 7.4 cm). A high number of patients, 47 patients (94%) out of 50, showed good healing at the donor site. Wound impairment was seen in 3 patients (6%), minor wound dehiscence in 2 patients, and severe wound dehiscence in 1 patient. In the recipient site, delayed healing was observed in 2 patients (4%). CONCLUSION: FTSG from the groin to repair soft tissue defects in reconstruction surgery is a good method due to the relatively big size of the graft, decreasing morbidity at the donor site, and higher graft survival rates.ope

NORMAL ERUPTION GUIDANCE OF UNERUPTED PERMANENT TEETH ASSOCIATED WITH DENTIGEROUS CYST BY DECOMPRESSION : 5 CASES REPORT

The purpose of this report is to describe a treatment method of dentigerous cyst associated with unerupted permanent teeth in mixed dentition patients. In our cases, extraction of infected primary teeth was followed by decompression of the cyst. At the same time, parts of the cystic walls were sent for histopathological examination. Decompression was performed by inserting a rubber tube into the cystic cavity through the extraction socket. The cystic cavity was kept open by means of vigorous use of a syringe by patient. Postoperative panoramic radiograph was taken bimonthly. After $5{\sim}12$ months, the impacted permanent teeth were erupted on the desired position. All cases presented favorable result. By extracting the infected primary teeth, and opening the cyst for continuous drainage, it was possible to achieve spontaneous eruption of the involved permanent teeth into the proper position. In all our cases, there was no sign or symptom of recurrence of the cyst up to postoperative 18 months.ope

SELECTIVE DEEP LOBE PAROTIDECTOMY FOR PRESERVATION OF PAROTID FUNCTION: A CASE REPORT

Tumors of the deep lobe of parotid gland are rare. These benign tumors have usually been treated by total parotidectomy, which has functional and esthetic side effects. Recently, there has been a trend for operations of parotid gland benign tumors to be less radical and selective deep lobe parotidectomy has been introduced. This technique preserves the superficial lobe and facial nerve when tumor is located in the deep lobe. Selective deep lobe parotidectomy preserves parotid salivary function, minimizes the incidence of facial nerve damage and gustatory sweating (Frey's syndrome) and improves cosmetic outcome. We report a case of pleomorphic adenoma of the deep lobe that was successfully treated by selective deep lobe parotidectomy with satisfactory result.ope

Comparative analysis of the amount of postoperative drainage after intraoral vertical ramus osteotomy and sagittal split ramus osteotomy

Objectives: The purpose of this retrospective study was to compare the amount of postoperative drainage via closed suction drainage system after intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO). Materials and Methods: We planned a retrospective cohort study of 40 patients selected from a larger group who underwent orthognathic surgery from 2007 to 2013. Mean age (range) was 23.95 (16 to 35) years. Patients who underwent bilateral IVRO or SSRO were categorized into group I or group II, respectively, and each group consisted of 20 patients. Closed suction drainage system was inserted in mandibular osteotomy sites to decrease swelling and dead space, and records of drainage amount were collected. The data were compared and analyzed with independent t-test. Results: The closed suction drainage system was removed at 32 hours postoperatively, and the amount of drainage was recorded every 8 hours. In group I, the mean amount of drainage was 79.42 mL in total, with 31.20 mL, 19.90 mL, 13.90 mL, 9.47 mL, and 4.95 mL measured at 0, 8, 16, 24, and 32 hours postoperatively, respectively. In group II, the mean total amount of drainage was 90.11 mL, with 30.25 mL, 25.75 mL, 19.70 mL, 8.50 mL, and 5.91 mL measured at 0, 8, 16, 24, and 32 hours postoperatively, respectively. Total amount of drainage from group I was less than group II, but there was no statistically significant difference between the two groups (P=0.338). There was a significant difference in drainage between group I and group II only at 16 hours postoperatively (P=0.029). Conclusion: IVRO and SSRO have different osteotomy design and different extent of medullary exposure; however, our results reveal that there is no remarkable difference in postoperative drainage of blood and exudate.ope

DNA-단일벽탄소나노튜브 복합체의 형성과 특성 규명에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2011.8. 이정훈.Docto

Chinas anti-monopoly law : enactment process, contents, implications

Thesis(masters) --서울대학교 대학원 :국제학과(국제지역학전공),2008. 8.Maste

On global financial reporting issues : fair value measurement

Thesis(masters) --서울대학교 경영전문대학원 :경영학과(SNUGlobal MBA전공),2010.8.Maste

Determinants of patients' intent to revisit at national university hospitals in Korea

보건행정학과/석사[한글] 국립대 병원 입원환자들의 재이용 의사 결정요인을 알아보기 위하여 11개 국립대 병원의 환자들을 대상으로 자기기입식 또는 면접조사를 실시하였다. 설문내용은 전반적 만족도와 재이용 의사에 영향을 미치는 요인을 외래 8가지, 입원 9가지로 정하고, 다시 요인별로 세부적인 특성 변수를 측정하였다. 외래 환자의 재이용 의사 결정에 가장 큰 효과를 미치는 변수는 건강회복정도(.242)로 나타났고 전반적 만족(.231), 의사 요인(.185), 직원 요인(.158) 순으로 유의한 영향을 미치는 것으로 나타났다. 또한, 입원 환자의 경우는 건강회복정도(.241), 간호사 요인(.193), 의사 요인(.144), 전반적 만족도(.120), 입원절차 요인(.102)의 순으로 유의한 영향을 미치는 것으로 나타났다. 한편 재이용 의사에 총효과로는 유의하게 나타나지 않았으나 절차 요인, 직원 요인, 시설 편의성 요인, 입원생활의 질 요인 등도 전반적 만족도를 통해서 재이용의사에 영향을 미칠 수 있음을 알 수 있었다. 따라서 환자들의 건강회복에 대한 기대에 부응하기 위하여 우수한 의료진과 장비를 갖추는 노력과 더불어 진료과정의 표준화, 의료서비스 질 관리 등 양질의 의료서비스를 제공할 수 있도록 의사 및 간호사뿐만 아니라 전 직원의 체계적인 교육과 보상이 필요하다고 하겠다. 또한 장기간 병원에서 생활하는 입원환자들을 위한 사생활 보장 및 시설 환경면에서도 세심한 배려가 요구된다. 본 연구는 국내 최초로 전국 국립대 병원 환자를 대상으로 병원 재이용 의사에 영향을 미치는 다양한 요인들을 규명하고자 시도하였다는 데 큰 의의가 있다. 그러나 연구 자료가 일회의 설문조사를 통해 수집한 단면자료이고, 또한 국립대 병원 환자만을 대상으로 하였으므로 본 연구 결과를 전체 병원의 환자들에게 일반화하는 데에는 신중을 기할 필요가 있다. 비록 국립대 병원이 수익성을 최고 목표로 하는 민간병원과는 조금 다른 성격을 가지고 있기는 하지만, 최근 환자 중심의 병원과 운영 효율성을 강조하는 사회 전반적인 흐름을 인식할 때, 관료적 틀에 안주해 오던 국립대 병원 역시 독자생존 할 수 있기 위해서는 여러 차원에서 환자 만족도를 향상시키고 나아가 병원 재이용 의사를 제고하기 위한 경쟁력 강화 전략이 필요할 것으로 판단된다. [영문]This study purports to investigate the determinants of patients'' intent to revisit at 11 national university hospitals in Korea. A total of 8 independent variables for outpatients, 9 independent variables for inpatients, and an intervening variable of overall patient satisfaction were selected from literature review. The independent variables for outpatients contain the level of satisfaction with physicians, nurses, ancillary staff, administrative procedure, medical cost, physical environment, facility convenience. and health recovery. With regard to the independent variables for inpatients, the quality of ward services was added to the those of outpatients. Each variable contains 3 to 8 items measuring the level of satisfaction with various aspects of the variable. The sample used in this study consisted of 879 outpatients and 821 inpatients. Data were collected with interview survey and analyzed using path analysis. The major findings of the study are as follows: 1) The following variables, listed in order of size, have significant positive effect on the intent to revisit of outpatients : health recovery, overall satisfaction, satisfaction with physicians, and ancillary staff. 2) The following variables, listed in order of size, have significant positive effect on the intent to revisit of inpatients : health recovery, satisfaction with nurses and physicians, overall satisfaction, and administrative procedure. 3) The following variables of admission procedure, satisfaction with ancillary staff, facility convenience, quality of ward services were found to have significant positive effect only on the level of overall satisfaction, even though they do not have significant total effect on the intent to revisit. The results of the study indicate that Korean national university hospitals should make an effort to improve the satisfactory level of patients with clinical outcome, services provided by physicians, nurses, and ancillary staff, and the quality of administrative procedure for enhancing the intent to revisit of patients.ope