http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
항공엔진 열화데이터 기반 잔여수명 예측력 향상을 위한 데이터 전처리 방법 연구
윤연아,정진형,임준형,장태우,김용수 한국산업경영시스템학회 2020 한국산업경영시스템학회지 Vol.43 No.2
Recently, a study of prognosis and health management (PHM) was conducted to diagnose failure and predict the life of air craft engine parts using sensor data. PHM is a framework that provides individualized solutions for managing system health. This study predicted the remaining useful life (RUL) of aeroengine using degradation data collected by sensors provided by the IEEE 2008 PHM Conference Challenge. There are 218 engine sensor data that has initial wear and production deviations. It was difficult to determine the characteristics of the engine parts since the system and domain-specific information was not provided. Each engine has a different cycle, making it difficult to use time series models. Therefore, this analysis was performed using machine learning algorithms rather than statistical time series models. The machine learning algorithms used were a random forest, gradient boost tree analysis and XG boost. A sliding window was applied to develop RUL predictions. We compared model performance before and after applying the sliding window, and proposed a data preprocessing method to develop RUL predictions. The model was evaluated by R-square scores and root mean squares error (RMSE). It was shown that the XG boost model of the random split method using the sliding window preprocessing approach has the best predictive performance.
윤연이,홍유진,김형관,김정아,나진오,양동현,김영진,최의영 대한영상의학회 2014 Korean Journal of Radiology Vol.15 No.6
Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.
캐비닛 엑스선 검색장비 이미지품질평가 고도화 방안 연구
윤연아 ( Yeon Ah Yoon ),정진형 ( Jin Hyeong Jung ),김용수 ( Yong Soo Kim ) 한국품질경영학회 2021 품질경영학회지 Vol.49 No.1
Purpose: This study proposes methods and procedures for evaluating imaging security systems quality of cabinet x-ray screening system to enhance performance certification technology. Also, conducted a comparative analysis of the literature of test-kit for imaging security quality evaluation. Methods: Comparative analysis of the test-kits and related documents for image quality assessment of cabinet x-ray screening equipment. This allows assessment items were selected and the methods for each assessment item were proposed. In addition, the configuration method of the assessment team was established by applying the technology readiness assessment(TRA). Results: Four of the assessment items were selected when estimate image quality by a comparative analysis of literature. For each assessment item, the evaluation method and minimum level of availability were determined. Finally, this paper proposes an imaging quality assessment of cabinet X-ray imaging security systems. Conclusion: Development of imaging security systems evaluation procedures for cabinet X-ray screening systems can be help improve performance certification of aviation security equipment.
윤연이,홍유진,김형관,김정아,나진오,양동현,김영진,최의영 대한심장학회 2014 Korean Circulation Journal Vol.44 No.6
Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technicaldevelopments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guidelinewhich is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilizationof CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline isa joint report of the Korean Society of Cardiology and the Korean Society of Radiology. Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technicaldevelopments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guidelinewhich is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilizationof CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline isa joint report of the Korean Society of Cardiology and the Korean Society of Radiology.
SHAP를 활용한 중요변수 파악 및 선택에 따른 잔여유효수명 예측 성능 변동에 대한 연구
윤연아(Yeon Ah Yoon),이승훈(Lee Seung Hoon),김용수(Yong Soo Kim) 한국산업경영시스템학회 2021 한국산업경영시스템학회지 Vol.44 No.4
Recently, the importance of preventive maintenance has been emerging since failures in a complex system are automatically detected due to the development of artificial intelligence techniques and sensor technology. Therefore, prognostic and health manage-ment (PHM) is being actively studied, and prediction of the remaining useful life (RUL) of the system is being one of the most important tasks. A lot of researches has been conducted to predict the RUL. Deep learning models have been developed to improve prediction performance, but studies on identifying the importance of features are not carried out. It is very meaningful to extract and interpret features that affect failures while improving the predictive accuracy of RUL is important. In this paper, a total of six popular deep learning models were employed to predict the RUL, and identified important variables for each model through SHAP (Shapley Additive explanations) that one of the explainable artificial intelligence (XAI). Moreover, the fluctuations and trends of prediction performance according to the number of variables were identified. This paper can suggest the possibility of explainability of various deep learning models, and the application of XAI can be demonstrated. Also, through this proposed method, it is expected that the possibility of utilizing SHAP as a feature selection method.
Left Atrial Mechanical Function and Stiffness in Patients with Paroxysmal Atrial Fibrillation
윤연이,김현진,김성애,김성환,박재형,박경하,최성훈,김민규,김현숙,조구영 한국심초음파학회 2012 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.20 No.3
Background: Abnormalities in the left atrial (LA) structure and function may develop in patients with paroxysmal atrial fibrillation (AF). We sought to determine the contribution of LA mechanical function, including LA stiffness, to AF by comparing patients with paroxysmal AF with normal control subjects, and to evaluate whether LA mechanical function and stiffness are related with the structural changes of LA. Methods: Sixty-four paroxysmal AF patients (57 ± 13 years, 59% male) were studied, using a speckle tracking echocardiography,and were compared with 34 age-, gender-, and left ventricular (LV) mass-matched controls (53 ± 14 years, 61% male). LA volume indices, expansion index for reservoir function, active emptying fraction for contractile function, mitral annular velocities,and global longitudinal LA strain were measured. The ratio of E/e’ to LA strain was used as an index of LA stiffness. Results: Patients with paroxysmal AF had similar LV volume indices, ejection fraction, and diastolic function, when compared with that of the normal controls. However, paroxysmal AF patients showed increased LA volume indices and decreased LA reservoir function, but similar contractile function. LA stiffness was increased in patients with paroxysmal AF than in the control subjects (0.40 ± 0.25 vs. 0.29 ± 0.10, p = 0.002), and was related with LA volume indices and reservoir function. Conclusion: Patients with paroxysmal AF have decreased LA reservoir function and increased stiffness, in comparison with that of the control subjects. LA stiffness was significantly related with LA volume indices and reservoir function. LA stiffness can be used for the assessment of LA function in patients with paroxysmal AF.
해외파견 병원근로자의 문화적응 스트레스와 직무만족이 조직몰입에 미치는 영향 -아랍에미리트 중심으로-
윤연서,Yun, Yeon-Seo 한국융합학회 2021 한국융합학회논문지 Vol.12 No.4
본 연구는 해외파견 병원근로자를 대상으로 문화적응 스트레스와 직무만족이 조직몰입에 미치는 영향을 파악하기 위해 시행되었다. 이를 위해 아랍에미리트에 파견된 병원근로자 107명을 설문조사하여 SPSS 25.0을 이용하여 분석하였다. 연구결과는 첫째, 문화적응 스트레스는 평균 83.01점, 직무만족은 평균 26.61점, 조직몰입은 평균 20.85점으로 나타났다. 둘째, 문화적응 스트레스가 낮을수록 직무만족도와 조직몰입은 높게 나타났으며, 직무만족도가 높을수록 조직몰입은 높게 나타났다. 셋째, 조직몰입에 영향을 미치는 요인으로는 직무만족도가 가장 높게 예측되었으며 72%의 설명력을 나타내었다. 그 밖의 요인으로는 가족동반, 해외체류경험, 사전교육, 문화적응 스트레스가 조직몰입에 영향을 미치는 것으로 나타났다. 그러므로, 해외파견 병원근로자의 조직몰입향상을 위해서 문화적응 스트레스를 줄이고 직무만족도를 높이는 다양한 프로그램 개발 및 방안이 마련되어야 하겠다. This study was examined the impact of acculturation stress and job satisfaction on the organizational commitment among dispatched hospital-workers in UAE. Data were collected with a convenience sample of 107 from March 1 to August 30, 2016. Analysis was conducted using t-test, ANOVA, Spearman rank-order correlation coefficient and Hierarchical regression analysis. The results of the study showed that first, the lower the acculturation stress, the higher the job satisfaction and organizational commitment, and the higher the job satisfaction, the higher the organizational commitment. Second, job satisfaction was significant to predict the level of organizational commitment among dispatched hospital-workers in UAE. Therefore, it is important not only to enhance the job satisfaction but also to reduce the acculturation stress before dispatch in order to improve the organizational commitment of dispatched hospital-workers, and various programs need to be developed for such education.