Experimental Study on the Motion of Floating Structure for Design of Wave Energy Generation Systems

In this paper, a measurement technique which can measure simultaneously the motions of a free-floating structure and the flows around it is introduced. To investigate the flow field and the motion of the floater, we constructed a measurement system with which analysis on the results of the interactions between fluid flows and structures motions was carried out. The measurement system consists of four cameras, a laser, and a host computer. The laser was used to illuminate the tracer particles. The particles' images were used to reconstruct the 3D measurement volume. The study focuses on the influences of the fluid viscosity onto the motion of the floating structure. A cylindrical structure (d=30mm, L=100mm) was put over the water surface. The motions of the floating structure was produced by the wave generated in the water channel. The floating structure is made of acrylic and the waves were generated by a DC servo motor which was installed at the top of the channel. 4 wave conditions were generated by the motor rotation speed with 40rpm, 46rpm, 53rpm and 59rpm. The wave height and frequency were measured by a ultrasound-based level sensor(UltraLab ULS 20130). After confirming the wave generated with the motor speed 40rpm to be optimal to the actual sea condition, the floating model was installed in the water channel. Simultaneous measurement was performed for the structure's motion and the flow motion around it. For the measurement of the structure's motions, ‘Bidirectional Motion Tracking Algorithm’ was adopted as target tracking method. On the other hand, For the measurement of the flow motion, tomographic flow visualization technique in which MART algorithm was used. The structure's motions and the flow motions were quantitatively measured by the constructed measurement system, and the their feasibility for the study of viscosity effects of the waves was confirmed.제1장 서 론 1 1.1 연구의 필요성 및 배경 1 1.2 연구의 목적 2 1.3 파력발전시스템의 개요 3 1.4 파력발전시스템의 분류 6 제2장 파랑에 따른 부유체 운동 측정 해석 14 2.1 실험장치 및 방법 14 2.2 파 발생 실험 및 결과 29 2.3 부유체 운동 측정 원리 및 측정 결과 34 2.4 부유체 주위 유동장 측정 원리 및 측정 결과 47 제3장 결론 77 참고문헌 7

통신용 소프트웨어의 사용자 인터페이스 디자인에 관한 연구 : GUI를 중심으로

학위논문(석사)--서울대학교 대학원 :산업디자인과 시각디자인전공,1995.Maste

Incidence and risk of osteoporotic refractures in cancer survivors compared to controls - a nationwide claims study in Korea

학위논문 (석사) -- 서울대학교 대학원 : 보건대학원 보건학과(보건학전공), 2020. 8. 성주헌.Background: Osteoporosis is the most common bone disorder and especially occurred on hip and vertebrae and frequently worsened to osteoporotic fracture. Osteoporotic fracture causes high mortality by disabling the physical activities. Incidence of cancer is a substantial risk factor on osteoporotic fracture and especially breast and prostate cancer contribute to incidence of refractures. Furthermore, relative risk of mortality of refracture patient is 1.4 to fracture patients who had no relapse. Recently, Fracture Liaison Service (FLS) and high adherence rate of Bisphosphonate have reduced refracture rate on cancer patients. Although there are prior studies researching the association of refracture and cancer diagnosis, few studies with larger subjects and long-term time series study observed the refracture rate on cancer patients. The study purpose is to comprehend the overall incidence rate and survival rate of osteoporotic fracture and relapse on cancer patients and primary risk factors of osteoporotic fracture following the appropriate policy making which includes persistent monitoring on high-risk group. Methods: Using patients tailored claim data of National Health Insurance Services (NHIS) from 2006 to 2018, osteoporotic fracture patients who have history of breast or prostate cancer was set to exposure group and no history of cancer as controls to make the retrospective nested cohort study. To ascertain the fracture code as osteoporotic fracture, patients older than 50 years old were only included and subjects who had history of osteoporotic fracture in 2006 were excluded in the analysis. Hip, vertebra, radius and humerus fractures were defined by main or sub disorder with ICD-10 codes and operational codes. Refracture was defined as secondary fracture more or equal than 180 days after primary fracture index date. 1:1 Propensity score matching with age, sex, level of insurance payment, residence, Charlsons comorbidity index excluding breast and prostate cancer were conducted. Baseline demographic characteristics of exposure and control group will be analyzed by Pearsons chi-square test to categorical variable and student t-test to continuous variable. Primary endpoint is the incidence rate of osteoporotic refracture. Secondary endpoint will be two types of cancer and cumulative incidence ratio of osteoporotic fractures in each fracture type and total fracture Survival rate will be calculated by cox-proportional hazards model with covariates including age, sex, location, CCI score. Results: 1,179,400 patients were diagnosed as having primary osteoporotic fracture and 23,202 patients are cancer patients comorbid with osteoporotic fracture. Compared to both control group before and after propensity score matching, patients with cancer history were statistically lower survival rate. Odds ratio of refracture comorbid with cancer was higher in overall fractures while stratification of OR showed that cancer comorbidity had lower odds ratio than patients who had no cancer history. Vertebral fractures cumulative refracture rate was the highest in each group and refracture of radius, hip, humerus followed in sequence. Except for hip fracture, there is statistically different in trend of refracture incidence and older age was the most powerful covariate of mortality (HR = 1.941, CI = 1.892, 1.991) Conclusion: Cancer patients have higher incidence and mortality of most types of osteoporotic refracture than patients who have no history on cancer except for vertebral cancer. Longitudinal follow-up cares and adding medication and chemotherapy records are required to monitor cancer patients to prevent relapse of fracture.연구배경 및 목적: 골다공증은 가장 흔한 골질환 중 하나로 고관절 및 척추에서 가장 많이 발생하며, 골다공증성 골절로 자주 악화된다. 골다공증성 골절은 신체 거동을 어렵게 하여 욕창, 요로감염 등 내과적 합병증 및 사망률을 높이며 암의 발생도 골다공증성 골절 발생의 유의한 요인이 된다. 거의 모든 종류의 암은 항암요법 및 면역 반응 등으로 골다공증성 골절을 유발시키는 위험요인이 되며, 상대적으로 암의 병력이 없는 사람들보다 골다공증성 골절을 호발시킬 수 있다. 골다공증성 골절은 재골절의 예방이 중요한데, 골다공증성 골절이 한 번만 일어난 환자에 비하여 재골절이 발생한 환자는 사망의 상대 위험도가 1.4배 높아지는 것으로 알려져 있다. 골절 예방 프로그램 및 높은 복약 순응도가 암 환자의 골절 예방에 도움이 된다고 외국에서 연구된 바가 있으나 암 환자 및 골절 환자의 재골절 발생에 대하여 비교적 대규모의 연구나 장기 추적 관찰 연구는 부족한 실정이다. 본 연구를 통하여 전체적인 주요 암 환자에서의 골다공증성 골절 및 재골절의 발생율을 파악하고 골다공증성 골절 발생의 위험 요인을 분석하여 골다공증성 골절의 고위군을 파악하고, 골절 예방을 적극적으로 도입할 필요성을 검토하고자 한다. 연구방법: 본 연구는 건강보험공단의 맞춤형 청구자료를 신청하여 2006년부터 2018년 안에 유방암 및 전립선암, 골다공증성 기록이 있는 환자군을 추출하였다. 골다공증성 골절의 병력이 있는 환자 중 골절보다 먼저 유방암, 전립선암 병력이 있는 경우를 노출군으로 설정하였고, 암 병력이 없는 골절 환자를 대조군으로 설정하였다. 골절의 진단 코드를 골다공증성 골절로 설정하기 위하여 50세 이상의 환자만 연구에 포함하였고 2006년에 골절 관련 기록이 있는 환자는 연구 대상에서 재외하였다. 골절의 범위는 고관절, 척추, 원위요골 및 근위상완골이며 재골절의 정의는 첫 번째 골절이 일어난 이후 최소 180일 이후로 설정하였으며, 척추 골절을 제외한 나머지 골절은 첫 번째 재골절만 재골절로 인정하였다. 1:1 성향 점수 매칭을 통하여 연령, 성별, 보험지불 등급, 거주지역, 노출에 해당하는 암을 제외한 찰슨동반질환지수를 공변량으로 설정하였다. 일차 평가 변수는 골다공증성 재골절의 군별 발생률이며 층화 콕스 비례위험모형을 이용하여 생존율을 이차 평가 변수로 설정하였다. 연구결과: 1,179,400 명의 환자들이 골다공증성 골절의 병력이 있는 것으로 나타났고 23,202명의 전립선 및 유방암 환자들이 골다공증성 골절을 경험하였다. 골다공증성 골절과 재골절은 연도별로 단조증가하였으며, 암 환자와 암의 병력이 없는 환자 모두 척추 골절의 발생률이 가장 높은 것으로 나타났고, 80세에서 89세의 발생률이 가장 높았으며, 원위요골 골절의 경우는 60 – 69세의 발생률이 모든 연도에서 가장 높은 것으로 나타났다. 성향점수 매칭 전후로 비교하였을 때에 척추 골절의 경우만 제외하고 모든 골절에서 암의 병력이 있는 골절 환자들의 생존율이 더 낮았으며, 전체적인 암 환자의 골다공증성 재골절의 승산비는 암이 없는 환자들보다 더 높게 나타났지만 골절 종류별로 층화하였을 때 근위상완골의 경우는 오즈비 차이가 유의하지 않았고 고관절, 척추, 원위요골의 경우는 승산비가 암이 있는 경우에 더 낮은 것으로 나타났으며 골절별 사망률은 고관절이 가장 높았고 척추 골절, 근위 상완골, 원위 요골 순이었다. 거주 지역을 제외하고 사망 위험비에 높은 연령, 남성, 낮은 보험 지불 등급 및 높은 CCI score가 통계적으로 유의한 영향을 미쳤으며, 높은 연령의 기여 위험도가 가장 높은 것으로 나타났다 (HR = 1.941, CI = 1.892, 1.991). 결론: 암 환자들은 암 병력이 없는 환자들보다 높은 재골절의 발생과 전체적으로 낮은 생존율을 보였으나 골절별로 층화하였을 때 승산비는 암의 병력이 없는 골절 종류별 환자들보다 일부 낮은 것으로 나타났다. 암 환자에게 사용된 화학 요법의 종류 및 골다공증성 골절 특이적 약물 소지율에 따른 추가적인 종단 연구가 암의 병력과 골다공증성 재골절 발생의 인과성 분석을 위하여 필요할 것으로 생각된다.Chapter 1. Introduction 1 Chapter 2. Methods 6 2.1 Study data and participants 6 2.2 Inclusion and exclusion criteria 6 2.3 Study variables 7 2.4 Statistical analysis 8 Chapter 3. Results 10 Chapter 4. Discussion 26 4.1 Discussion 26 4.2 Conclusion 28 References 29 Appendix 33 Abstract (Korean) 38Maste

Authentic leadership of nursing managers, Psychological safety in work teams and Intention to medication error reporting of nurses

투약오류보고는 투약오류를 감소시키기 위한 개선 활동 중 하나로 투약오류보고율을 예측할 수 있는 투약오류 보고의도를 향상시키는 것은 환자안전사고를 예방하고 재발을 방지하기 위한 방안 중 하나이다. 이에 본 연구에서는 간호사가 인식하는 간호관리자의 진성리더십, 팀 내 심리적 안전감과 투약오류 보고의도와의 관계를 파악하기 위한 서술적 조사연구를 시행하였다. 본 연구는 간호사 167명을 대상으로 구조화된 설문지를 이용하여 연구를 진행하였으며, 자료 분석은 SPSS statistics 26.0과 SPSS Process macro ver 3.4.1 프로그램을 이용하여 빈도분석, 기술통계, independent t-test, ANOVA, Pearson’s correlation coefficient, 다중회귀분석, 부트스트랩을 이용한 Process macro model 4로 분석하였다. 연구결과 진성리더십 3.41±.56점, 심리적 안전감 3.50±.52점, 투약오류 보고의도 71.06±19.13점으로 나타났고, 투약오류 보고의도에 영향을 미치는 요인으로는 3회 이상의 투약오류 관련 교육참여(β=.28, p=.003), 팀 내 심리적 안전감(β=.21, p=.004), 투약 근접오류경험(β=-.17, p=.041)으로 나타났다. 진성리더십이 투약오류 보고의도에 미치는 영향에서 심리적 안전감을 통한 간접효과가 검증되어(β=.2042, CI=.0025~.4892) 간호관리자의 진성리더십과 간호사의 투약오류 보고의도 사이에서 팀 내 심리적 안전감은 매개 역할을 하는 것으로 검증되었다. 이상의 연구결과를 종합하면, 투약오류 보고의도를 높이기 위해서는 투약오류에 관한 정의, 사례, 투약오류보고 체계, 오류 보고의 중요성이 포함된 체계적이고 반복적인 투약오류 관련 교육 프로그램을 구축하는 것이 필요하고, 투약오류보고로 겪은 간호사의 부정적인 경험을 극복하고, 심리적 안전감을 증진시키기 위한 조직적 접근 전략과 간호관리자의 진성리더십 개발을 위한 노력이 필요하다. The medication error report is one of the improvement activities to reduce medication error, and improving the intention of reporting medication error that can predict medication error rate is one of the measures to prevent patient safety accidents. Thus, in this study, a descriptive investigation study was conducted to identify the relationship between the authentic leadership of the nurse's perceived nursing manager, the psychological safety in work team, and the intent to report the medication error. This study was conducted on 167 nurses using structured questionnaires. The collected data were analyzed by the SPSS WIN 26.0 and SPSS　process macro ver 3.4.1 software program and descriptive statistics, such as independent t-test, ANOVA, Pearson/s correlation coedfficient, multiple linear regressionanlysis, Scheff test, and mediation analysis. Mediation alalysis was conducted using SPSS macro process model 4 to examine mediationi effect of psychological safety in work team on the relationship between authentic leadership of nursing managers and intention to medication error reporting of nurses. The study found that authentic leadership was 3.41±.56 points, psychological safety was 3.50±.52 points, and intention to medication error reporting was 71.06±19.13 points, and factors affecting the intention to medication error reporting of nurses were participation in education related to medication error (β =.28, p=.003), psychological safety in work team( =.21, p=.β 004), experience of near miss related medication error(β=-.17 and p=.041). The specific indirect effect through psychological safety in work team was β=.2042(CI=.0025-4892). Between the authentic leadership of nursing manager and the intention of the nurse to report an error in medication, psychological safety in the team has been verified to play a mediating role. These results showed that it is necessary to establish a systematic and repetitive medication error-related education program that includes the definition of medication error, cases, medication error reporting system, and the importance of error reporting, and to overcome the negative experiences of nurses who have experienced medication error reporting, and to make efforts to develop authentic leadership of nursing managers and to enhance psychological safety in work team.open석

Inhibitory effects of Artemisia asiatica on osteoclast formation induced by periodontopathogens

Bone resorption surrounding tooth root causes tooth loss in periodontitis patients. Osteoclast has bone resorption activity. Effects of Artemisia asiatica on bone resorption induced by periodontopathogens, Porphyromonas gingivalis and Treponema denticola, were examined using co-culture systems of mouse osteoblasts and bone marrow cells. Addition of A. asiatica ethanol extract to bacterial sonicate abolished bacteria-induced osteoclastogenesis. To determine inhibitory mechanism of A. asiatica against osteoclastogenesis, effects of A. asiatica on expressions of osteoclastogenesis-inducing factors such as receptor activator of NF-κB ligand (RANKL), prostaglandin E2 (PGE2), interleukin (IL)-1, and tumor necrosis factor (TNF)-α, in osteoblasts were examined. A. asiatica suppressed expressions of RANKL, PGE2, IL-1β, and TNF-α increased by each bacterial sonicate. These results suggest inhibitory action of A. asiatica against osteoclastogenesis is associated with downregulations of RANKL, PGE2, IL-1β, and TNF-α expressions.restrictio

Prostaglandin E2 Is a Main Mediator in Receptor Activator of Nuclear Factor-κB Ligand-Dependent Osteoclastogenesis Induced by Porphyromonas gingivalis, Treponema denticola, and Treponema socranskii

BACKGROUND: Periodontitis is an inflammatory disease that often leads to destruction of alveolar bone; a number of bacteria in subgingival plaque are associated with bone destruction in periodontitis. To understand the mechanism of how periodontopathogens induce osteoclastogenesis, we determined which mediators are involved in the osteoclastogenesis. METHODS: We investigated effects of sonicates from three periodontopathic bacteria, Porphyromonas gingivalis, Treponema denticola, and Treponema socranskii, on osteoclast formation in a co-culture system of mouse calvaria-derived osteoblasts and bone marrow cells. The osteoclast formation was determined by tartrate resistant acid phosphatase (TRAP) staining. The expression of the receptor activator of nuclear factor-kappa B ligand (RANKL), prostaglandin E(2) (PGE(2)) and osteoprotegerin (OPG) in mouse calvaria-derived osteoblasts was determined by immunoassay. RESULTS: Each bacterial sonicate induced the osteoclast formation in the co-culture system. These bacterial sonicates increased the expression of RANKL and PGE(2), and decreased the expression of OPG in osteoblasts. The addition of OPG, an inhibitor of RANKL, in the co-culture completely suppressed the osteoclastogenesis that was stimulated by each bacterial sonicate. Indomethacin, which is an inhibitor of PGE(2) synthesis, reduced more than 88% of the osteoclast formation induced by each bacterial sonicate. Indomethacin inhibited more than 80% of RANKL expression in osteoblasts induced by T. denticola and T. socranskii, and 59% by P. gingivalis. Indomethacin completely recovered the depression of OPG expression in osteoblasts by T. denticola and T. socranskii to the level of the untreated osteoblasts. Indomethacin recovered the reduction of OPG expression by P. gingivalis to 67%. CONCLUSION: These findings suggest that the osteoclastogenesis by P. gingivalis, T. denticola, and T. socranskii is mediated by a RANKL-dependent pathway and that PGE(2) is a main factor in the pathway by the enhancing of RANKL expression and the depression of osteoprotegerin, a RANKL inhibitor.restrictio

Effect of Treponema lecithinolyticum lipopolysaccharide on matrix metalloproteinase-9 expression

Bone resorption involves sequential stages of osteoclast precursor migration and differen-tiation of osteoclast precursors into multinucleated osteoclasts. Stromal cell derived factor (SDF)-1 is a chemotactic factor for osteoclast precursor migration. Matrix metalloproteinase (MMP)-9 is involved in migration of osteoclast precursors and activation of interleukin(IL)-1beta. Alveolar bone destruction is a characteristic feature of periodontal disease. Treponema lecithinolyticum is a oral spirochete isolated from the periodontal lesions. The effect of lipopolysaccharide(LPS) from T. lecithinolyticum on expression of SDF-1 and MMP-9 was examined in cocultures of bone marrow cells and osteblasts derived from mouse calvariae. T. lecithinolyticum LPS increased expression of MMP-9 in the coculture. Polymyxin B, an inhibitor of LPS, abolished the increase of MMP-9 mRNA expression by LPS. LPS did not increase the expression of SDF-1, IL-1beta and tumor necrosis factor(TNF)-alpha mRNA in cocultures. Prostaglandin E2(PGE2) up-regulated the expression of MMP-9 and NS398, an inhibitor of PGE2 synthesis, down-regulated the induction of MMP-9 expression by T. lecithinolyticm LPS. These results suggest that T. lecithinolytium LPS increases MMP-9 expression in bone cells via PGE2 and that the induction of MMP-9 expression by T. lecithinolyticum LPS is involved in alveolar bone destruction of periodontitis patients by the increase of osteoclast precursor migration and the activation of bone resorption-inducing cytokine.ope