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조민준,Seoung-Hwan Moon,Ji-Ho Lee,Jae Hyup Lee 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.5
Study Design: A nationwide, observational, and cross-sectional study targeting postmenopausal patients from 62 orthopedic outpatient clinics in Korea between October 2010 and February 2011. Purpose: This study was carried out to investigate comorbidity, trauma history, and the status of osteoporotic fracture treatment in Korean postmenopausal women. Overview of Literature: There has been little reports on the comorbidity, family history, trauma history, and treatment status of osteoporotic fractures in patients visiting the orthopedic outpatient clinics in Korea. Methods: A total of 1,255 postmenopausal women between the ages of 50 and 80 years were enrolled in the study and the population distribution was reflected by region. Comorbidity, familial history of osteoporosis, familial history of osteoporotic fracture, history of falls, and status of osteoporotic fracture management were evaluated using an interview and questionnaire. The relationship between family history of osteoporosis and bone mineral density was analyzed. Results: A number of patients (23%) had a family history of osteoporosis and 16.5% had a family history of fractures. Most (64.7%) of the patients had one or more comorbidities, including 58.8% exhibiting a chronic disease and 16.4% suffering from diseases that restrict exercise or walking. The results of the questionnaire indicated that 21.8% of these fracture patients had experienced a fracture previously and that the most common type of fracture was that of the spine. Lumbar spine bone mineral density was found to be lower in the presence of family history of osteoporosis. Conclusions: Postmenopausal women are liable to have osteoporotic fractures due to the high prevalence of osteoporosis, a history of falling, and the comorbidity with diseases that restrict ambulation. A better understanding of postmenopausal women in the orthopedic outpatient settings is important to the management of osteoporotic fractures.
폐암 환자의 정위적 체부 방사선 치료 시 양압지속유지기와 복부 압박기 적용에 따른 Intra Fractional Motion 차이에 대한 비교분석
조민준,유현종,조강철,박효국,윤종원,조정희,Cho, MinJun,Yoo, HyunJong,Cho, KangChul,Park, HyoKuk,Yoon, JongWon,Cho, JungHee 대한방사선치료학회 2021 대한방사선치료학회지 Vol.33 No.-
목적: 폐암 환자의 정위적 체부 방사선 치료 시 양압지속유지기(continuous positive airway pressure; CPAP)와 복부 압박기(abdominal compressor; AC)를 각각 독립된 표본에 적용하였을 때, 치료 중 표적의 위치변화값을 분석하여 표적 움직임 최소화에 보다 더 유용한 device 선별을 목표하였다. 대상 및 방법: 본원에서 시행한 폐암 정위적 체부 방사선 치료 시 CPAP과 AC를 사용한 환자 중 치료 Arc가 2개로 구성된 환자 26명을 후향적으로 분석하였다. 치료 중(2nd arc) CBCT를 사용하여 영상을 획득하고 발생한 치료 중 자세 변화(Intra Fractional Motion; IFM)를 비교분석하였다. 결과: 방향성을 통합한 102개의 관측수로 Welch's t-test를 수행하여 CPAP과 AC 간 IFM의 평균 차가 크게 유의미하지 않다는 사실을 확인할 수 있었다(p>0.05). 치료 중(2nd arc) CPAP에서 Translation(x, y, z) 이동값과 AC에서 Translation(x, y, z) 이동값을 3차원 공간상에서의 분포도로 확인했을 때 AC의 경우 중심점 부근에 집중적으로 분포되어있는 것을 확인할 수 있는 반면, CPAP의 경우 이상치 값들이 외각에 분포되어있는 것을 관찰할 수 있다. 세 개의 방향성 통합 비교분석에서 CPAP에서 평균, 표준편차 그리고 최대 오차 값은 0.13±0.15 cm, 0.70 cm로 나타났으며, AC에서 평균, 표준편차 그리고 최대 오차 값은 0.11±0.10 cm, 0.50 cm로 나타났다. CPAP에서 0.7 cm, 0.5 cm, -0.5 cm, -0.6 cm, -0.7 cm의 이상치가 보이지만 AC에서는 0.5 cm 이상치 값만이 존재했다. 결론: IFM 측면에서 AC가 CPAP에 비해 random error의 발생 빈도가 적었다. 하지만, CPAP과 AC 모두 각각의 고유한 장, 단점 및 적응증이 존재하며, CPAP과 AC 간 IFM의 평균 차가 크게 유의미하지 않으므로 임상적 상황에 맞는 device를 환자에게 적용함으로써 치료의 효율성을 증대시킬 수 있을 것으로 사료된다. Purpose: When applying continuous positive airway pressure (CPAP) and abdominal compressor (AC) to independent specimens in stereotactic body radiation therapy in lung cancer patients, the value of how much the target's position changed during treatment. By analyzing the target movement, we aimed to select a more useful device for minimizing the movement of the target. Materials and Methods: We retrospectively analyzed 26 patients with two treatment arcs among patients with CPAP and AC in stereotactic body radiotherapy for lung cancer. Images were acquired using CBCT during treatment (2<sup>nd</sup> arc), and intra-fractional motion (IFM) was compared and analyzed. Result: Welch's t-test was performed with 102 observations integrating three directions, and it was confirmed that the mean difference in IFM between CPAP and AC was not significantly significant (p→0.05). When the translation (x, y, z) shift value in CPAP during treatment (2nd arc) and the translation (x, y, z) shift value in AC were confirmed as a distribution in 3D space, in the case of AC, intensively near the center point. While it can be confirmed that they are distributed, in the case of CPAP, outlier values can be observed to be distributed outside. In the three directional integrated comparative analysis, the mean, standard deviation, and maximum error values in CPAP were 0.13±0.15 cm and 0.70 cm, and in AC, the mean, standard deviation, and maximum error values were 0.11±0.10 cm and 0.50 cm. In CPAP, outliers of 0.7 cm, 0.5 cm, -0.5 cm, -0.6 cm, and -0.7 cm were seen, whereas in AC, there were 0.5 cm outliers. Conclusion: In terms of IFM, AC had fewer random errors than CPAP. However, both CPAP and AC have their own advantages, disadvantages, and indications, and since the average difference in IFM between CPAP and AC is not significant, it is possible to increase the efficiency of treatment by applying a device suitable for the clinical situation to the patient.
가공 조건에 따른 CNC 공작기계의 스핀들 모터 전류 부하 예측 모델 개발
조민준,정양언,김유경,강호정,김태진 대한기계학회 2023 大韓機械學會論文集A Vol.47 No.7
A CNC machine is a production equipment used for precise processing and plays a key role in automation and flexible production. CNC machines have advantages of complex and sophisticated machining, but disadvantages of quality and productivity degradation owing to tool wear and frequent tool replacement. Tool wear is significantly affected by the tool load according to cutting conditions. Tool wear can be alleviated by relaxing the machining conditions, but this results in a decrease in productivity. Therefore, determining a balance between tool wear and machining time by setting appropriate machining conditions is important. Hence, in this study, a machine learning technique is used to develop a spindle motor current load model according to machining conditions. The current load of the CNC spindle motor is a factor correlated with the tool load and wear. Therefore, the developed model can be used to improve future machining conditions. CNC 공작기계는 소재의 정밀 가공을 위해 사용되는 생산 장비로 생산자동화 및 유연생산에 있어 핵심적 역할을 수행한다. CNC 공작기계는 복잡하고 정교한 가공에 장점이 있으나 공구의 마모로 인한 품질저하 및 잦은 공구 교체로 인한 생산성 저하가 문제가 된다. 공구의 마모는 절삭조건에 따른 공구 부하에 크게 영향을 받는다. 절삭조건을 완화하여 공구부하를 감소시키면 마모를 줄일 수 있으나 이는 생산속도의 저하를 초래한다. 따라서 적절한 가공 조건을 설정하여 공구 마모와 가공시간 간의 균형을 찾는 것이 중요하다. 이를 위해 본 연구에서는 머신러닝 기법을 이용하여 가공 조건에 따른 스핀들 모터의 전류 부하 예측 모델을 개발한다. CNC 스핀들 모터의 전류 부하는 공구 부하 및 마모와 상관성을 가지는 인자로 개발된 모델은 추후 가공조건을 결정하는 데 활용될 수 있다.