A Design for Hybrid Underwater Glider and The Estimation of Field Performance Using Model Test

The hybrid underwater glider (HUG) is an improved version of autonomous underwater glider which glide under the water by controlling their buoyancy and additional thruster. By the aid of the thruster, the maneuverability and performance of reaching to a target area can be improved. In this thesis, the structure of the HUG is designed through analyses on the hydrodynamics of the ship and empirical formula for the ship design. The ship hull design of the HUG was performed, using this, the drag of the HUG was analysed. The structure and capacity of the buoyancy engine were designed through the analysis on the HUG. Also, a mass transfer system was designed for attitude control of the HUG. And an hull pressure analysis was performed for 200m depth operation of the HUG using FEM analysis. Also, computer simulations on the hydrodynamics of the HUG were performed through estimation of the hydrodynamic coefficients. To test the performance of the actuator and to get hull coefficients, water tank tests were performed using the developed HUG. The results of the performance tests are presented and its results are discussed.1. 서 론 1.1 연구배경 및 목적 1 1.2 하이브리드 수중 글라이더 개념설계 2 2. 하이브리드 수중 글라이더 모델링 2.1 좌표계 및 정상상태 모델링 6 2.2 내부장치 구성 8 3. 선체 설계 및 해석 3.1 선체 설계 10 3.1.1 선형 설계 10 3.1.2 선체 저항 해석 11 3.1.3 최대 속도 추정 13 3.1.4 선체 구조 18 3.2 부력제어기 설계 21 3.2.1 부력제어기 구동 메커니즘 21 3.2.2 부력제어기 용량 해석 23 3.2.3 부력제어기 소비전력 24 3.2.4 부력제어기 구조 설계 26 3.3 자세제어기 설계 27 3.3.1 자세제어기 구동 메커니즘 27 3.3.2 자세제어기 용량 해석 27 3.3.3 자세제어기 구조 설계 29 3.4 추진기 설계 31 3.4.1 추진 성능 해석 31 3.4.2 추진기 구조 설계 32 3.4.3 추진기 성능시험 32 3.5 고정익 설계 34 3.6 방향타 설계 34 3.7 구성 종합 35 4. 구동 성능 시험 4.1 자항속도 측정 39 4.2 조종 성능 시험 40 4.3 수중 자세 유지 시험 41 5. 동역학 시뮬레이션 5.1 유체력 계수 추정 42 5.1.1 좌표계 및 외력성분 정의 42 5.1.2 유체정역학적 작용력 44 5.1.3 점성감쇠유체력 45 5.1.4 관성유체력 46 5.1.5 제어유체력 48 5.1.6 유체력 종합 50 5.2 시뮬레이션 51 5.2.1 활강각에 따른 최고속도 및 구간거리 53 5.2.2 부력제어량에 따른 최고속도 및 소모전력량 55 6. 결론 참고문헌 5

가족성 모야모야병 환자의 TIMP 유전자 단일 뉴클레오티드 다형성 분석

Thesis(doctor`s)--서울대학교 대학원 :의학과 신경외과학전공, 2005.Docto

Urologic outcome after surgery of lumbosacral lipoma 요천추 지방종 수술 후 비뇨기과적 결과

Thesis (master`s)--서울대학교 대학원 :의학과 신경외과학 전공,1999.Maste

The clinical outcomes of surgical management of anterior chamber migration of a dexamethasone implant (Ozurdex®)

PURPOSE: Our purpose was to describe the clinical course, and individualized management approaches, of patients with migration of a dexamethasone implant into the anterior chamber. METHODS: This was a retrospective review of four patients with seven episodes of anterior chamber migration of a dexamethasone implant. RESULTS: After 924 intravitreal dexamethasone injections, anterior migration of the implant occurred in four eyes of four patients (0.43%). All four eyes were pseudophakic: one eye had a posterior chamber intraocular lens in the capsular bag but in a post-laser posterior capsulotomy state, two eyes had a sulcus intraocular lens (IOL), and one eye had an iris-fixated retropupillary IOL. All eyes had a prior vitrectomy and no lens capsule. The time interval from injection to detection of the implant migration ranged from 2 to 6 weeks. Of the four eyes with corneal edema, only one eye required a corneal transplantation, although it was unclear whether the implant migration was the direct cause of the corneal decompensation because the patient had a history of bullous keratopathy resulting from an extended history of uveitis. All patients underwent surgical intervention: two patients with a repositioning procedure, and the other two patients with removal due to repeated episodes, although surgical removal was not always necessary to reverse the corneal complications. CONCLUSIONS: In our study, not all patients required surgical removal of the implants. Repositioning the implant back into the vitreous cavity may be considered as an option in cases involving the first episode with no significant corneal endothelial decompensation. Considering potential anterior segment complications and the loss of drug effectiveness together, an individualized approach is recommended to obtain the best treatment outcomes and to minimize the risk of corneal complications.restrictio

COMBINING EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY WITH STRUCTURAL OPTICAL COHERENCE TOMOGRAPHY AND BLOOD FLOW ANALYSIS FOR DETECTING CHOROIDAL NEOVASCULAR COMPLEXES IN PIGMENT EPITHELIAL DETACHMENTS

PURPOSE: This work aimed to describe the morphology of pigment epithelial detachment (PED) using optical coherence tomography angiography and to investigate its potential to detect choroidal neovascularization in various types of PEDs. METHODS: In this retrospective study, 53 patients diagnosed with PED after undergoing both optical coherence tomography angiography (AngioPlex, CIRRUS HD-OCT) and spectral domain optical coherence tomography (Spectralis SD-OCT) were included. RESULTS: Among the 53 eyes, flat vascularized PED (vPED) affected 21 eyes (40%), peaked vPED affected 10 eyes (19%), serous PED affected 12 eyes (23%), drusenoid PED affected 6 eyes (11%), and 4 eyes (7%) had multiple PED subtypes. The main underlying etiologies were pachychoroid spectrum disorder (30.2%), wet age-related macular degeneration (28.3%), central serous chorioretinopathy (18.9%), dry age-related macular degeneration (11.3%), and polypoidal choroidal vasculopathy (11.3%). Optical coherence tomography angiography identified neovascularization in 29 (94%) of the vPED eyes, 2 (17%) of the serous PED eyes, and all 4 (100%) mixed PED eyes. CONCLUSION: Optical coherence tomography angiography successfully identified neovascularization in both vPEDs and PEDs previously considered to be nonneovascular. However, structural OCT and blood flow analysis should be combined to interpret PED-associated neovascularization accurately in the clinic.restrictio

Long-term visual outcomes for treatment of submacular haemorrhage secondary to polypoidal choroidal vasculopathy

IMPORTANCE: There is no consensus on the optimal management of submacular haemorrhage (SMH) secondary to polypoidal choroidal vasculopathy (PCV). BACKGROUND: To compare the long-term outcome of three treatment strategies for PCV with SMH. DESIGN: Retrospective case series at two tertiary hospitals. SAMPLES: A total of 48 consecutive eyes treated between July 2006 and March 2016. METHODS: Patients were grouped according to the treatment received: 22 eyes with intravitreal bevacizumab (IVB), 14 with a combination of IVB and pneumatic displacement (PD) and 12 with IVB and vitrectomy (TPPV). MAIN OUTCOME MEASURES: Change in best-corrected visual acuity (BCVA) at onset and up to 24 months. Secondary measures included demographic data, imaging data and complications. RESULTS: Comparing the mean BCVAs of the groups revealed significant differences only at month 1 (P = 0.005). Changes in the mean BCVA over time revealed no significance in the resulting final BCVA (P = 0.062), which was 20 out of 155 (logMAR 0.89 ± 0.64) for IVB monotherapy, 20 out of 174 (0.94 ± 1.04) for combined IVB + PD, and 20 out of 195 (0.99 ± 0.90) for combined IVB + TPPV eyes. Sustained long-term improvement of over three Snellen lines was found in seven (31.82%) IVB monotherapy, 10 (71.43%) combined IVB + PD, and seven (58.33%) combined IVB + TPPV eyes (P = 0.043). SMH recurrence was observed in two eyes after IVB monotherapy and one eye after combined IVB + PD (P = 0.786). CONCLUSIONS AND RELEVANCE: IVB monotherapy appears to be as effective as combination therapies for treating SMH secondary to PCV with regards to BCVA at 24 months, and may be a cost-effective strategy for long-term management.restrictio

Guidelines for the Management of Unruptured Intracranial Aneurysm

Intracranial aneurysmal rupture causes subarachnoid hemorrhage which usually leads to fatality or severe disability. Treatment of unruptured intracranial aneurysms (UIAs) can substantially reduce the risk of rupture and prevent the grave consequences, but the risk of prophylactic treatment cannot be ignored. UIAs have diverse characteristics and management strategy needs to be tailored according to their location, size and clinical status. In the absence of level I evidence, the treatment guidance often relied on experts opinions and experience. Knowledge of the natural course and management risks of individual aneurysms can help to guide treatment decision, but the natural history is still controversial and risks are not clearly defined. The Korean Society of Cerebrovascular Surgeons (KSCVS) decided to issue a Korean version of UIA management guideline as a framework for the treatment decision and as a basis for future studies, following Guideline Development Manual of the Clinical Research Center for Stroke (CRCS). The organized committee systematically reviewed relevant literature and major guidelines published between January 2000 and July 2010 and took a developmental strategy of adaptation rather than de novo methods. On the basis of interpretation of the published evidences, recommendations were synthesized, and the level of evidence and the grade of recommendation were determined using the methods adapted from those of the US Agency for Healthcare Policy and Research and CRCS. The current guideline focuses on three domains of natural history, diagnosis and treatment of UIAs. The hierarchy of evidence and the recommendation grading indicate the current level by the literature and do not indicate the necessity or the prohibition of a certain clinical practice. Accordingly, this guideline cannot provide the answer for every clinical situation and should not take precedence over the clinical judgment of responsible physicians for individual patients. The final judgment regarding the care of a particular patient must be made by the physician and patient in light of circumstances specific to that patient. This is the first version of the UIA management guideline in Korea and new evidences will be timely and continuously updated in the future guidelines.N

Management of Asymptomatic Carotid Stenosis for Primary Stroke Prevention: 2012 Focused Update of Korean Clinical Practice Guidelines for Stroke

Extracranial carotid stenosis is a well-established, modifiable risk factor for stroke. Asymptomatic extracranial carotid stenosis is increasingly being detected due to the introduction of less-invasive and more-sensitive advanced diagnostic technologies. For severe asymptomatic stenosis, earlier pivotal clinical trials demonstrated the benefit of carotid endarterectomy over the best medical therapy. Since then, great advances have been made in interventional and medical therapies as well as surgical techniques. The first edition of the Korean Stroke Clinical Practice Guidelines for primary stroke prevention for the management of asymptomatic carotid stenosis reflected evidences published before June 2007. After the publication of the first edition, several major clinical trials and observational studies have been published, and major guidelines updated their recommendation. Accordingly, the writing group of Korean Stroke Clinical Practice Guidelines (CPG) decided to provide timely updated evidence-based recommendations. The Korean Stroke CPG writing committee has searched and reviewed literatures related to the management of asymptomatic carotid stenosis including published guidelines, meta-analyses, randomized clinical trials, and nonrandomized studies published between June 2007 and Feb 2011. We summarized the new evidences and revised our recommendations. Key changes in the updated guidelines are the benefit of intensive medical therapy and further evidence of carotid artery stenting as an alternative to carotid endarterectomy. The current updated guidelines underwent extensive peer review by experts from the Korean Stroke Society, Korean Society of Intravascular Neurosurgery, Korean Society of Interventional Neuroradiology, Korean Society of Cerebrovascular Surgery, and Korean Neurological Association. New evidences will be continuously reflected in future updated guidelines.N