• Advances in aircraft and spacecraft science
• /
• 제3권4호
• /
• pp.503-521
• /
• 2016

Variances in turbomachinery blades caused by manufacturing, operation or regeneration can result in modified structural behavior. In this work, the scatter of geometrical and material properties of a turbine blade and its influence on structure performance is discussed. In particular, the vibration characteristics and the lifetime of a turbine blade are evaluated. Geometrical variances of the surface of the blades are described using the principal component analysis. The scatter in material properties is considered by 16 varying material parameters. Maximum vibration amplitudes and the number of load cycles the turbine blade can withstand are analyzed by finite element simulations incorporating probabilistic principles. The probabilistic simulations demonstrate that both geometrical and material variances have a significant influence on the scatter of vibration amplitude and lifetime. Dependencies are quantified and correlations between varied input parameters and the structural performance of the blade are detected.

• 말소리와 음성과학
• /
• 제4권1호
• /
• pp.111-118
• /
• 2012

The purpose of this study was to characterize and determine variances of speaking fundamental frequency and vocal intensity depending on gender and three utterance conditions (spontaneous speech, reading, and counting). A total of 65 undergraduate students (32 male students, 33 female students) attending universities in Daegu, South Korea participated in this study. The subjects were all in their 20s. This study used KayPENTAX's Visi-Pitch IV (Model 3950) to measure the variances of speaking fundamental frequency (SFF0) and vocal intensity (VI). As a result, this study came to the following conclusions. First, it was found that both males and females showed no significant difference in SFF0 and vocal intensity among three utterance conditions. Second, this study sought to analyze differences in the variances of SFF0 between males and females. As a result, it was found that females showed significantly higher levels of four measured variances (SFF0 $SD^{**}$, SFF0 $range^{***}$, Min $SFF0^{***}$ and Max $SFF0^{***}$) than males on spontaneous speech. However, it was found that there was no significant difference between males and females in SFF0 range on reading or in SFF0 SD and SFF0 range on counting. It was found that there was no significant difference between males and females in the level of measured variances of vocal intensity depending on utterance conditions. Finally, this study made a comparison and analysis on differences in the variances of SFF0 and vocal intensity among utterance conditions. As a result, it was found that all the measured variances of SFF0 in males were most significantly reduced depending upon spontaneous speech which was followed by reading and counting respectively (SFF0 SD: p<.001, SFF0 range: p<.05, Max SFF0: p<.05). Females however, show no significant difference in the measured variances of SFF0 depending upon three utterance conditions. It was also found that the measured variances of vocal intensity in females were most significantly reduced depending on spontaneous speech that was followed by reading and counting (VI SD: p<.001, VI range: p<.001, Min VI: p<.01 Max VI: p<.05), while males showed no significant difference in the measured variances of vocal intensity depending on three utterance conditions. In sum, these findings suggest that variances of SFF0 in males are affected by three utterance conditions, while variances of vocal intensity in females are affected by three utterance conditions.

• Industrial Engineering and Management Systems
• /
• 제10권4호
• /
• pp.255-263
• /
• 2011

During the design process of a terminal, the handling capacity of a container yard needs to be evaluated in advance. This study suggests formulas for estimating the expectations and the variances of cycle times for various types of operations of a yard crane. Statistical analysis is used to estimate the expectations and variances. The main focus of this study is to show the impact of interdependencies among handling time elements on the expectation and variance of the cycle times; these interdependencies have not been considered in previous studies. Numerical experiments are done for evaluating the difference in the variance of cycle times and the waiting of trucks between the cases with and without the consideration of interdependencies.

• Journal of the Korean Data and Information Science Society
• /
• 제18권1호
• /
• pp.219-228
• /
• 2007

In this paper, we consider a decision-theoretic oriented, objective Bayesian inference for the ratio of two normal variances. Specifically we derive the Bayesian reference criterion as well as the intrinsic estimator and the credible region which correspond to the intrinsic discrepancy loss and the reference prior. We illustrate our results using real data analysis and simulation study.

• 한국측량학회지
• /
• 제17권3호
• /
• pp.225-231
• /
• 1999

위성영상의 통계적 분석에서는 트레이닝을 통하여 추정된 각 클래스의 평균과 분산을 통계적 유사성 결정의 근거로 사용한다. 따라서, 트레이닝 작업의 결과는 전체적인 분류정확도에 큰 영향을 주게 된다. 이상적인 위성영상 데이터의 분포는 정규분포에 근사한 것으로 가정되고 있으나, 실제로는 약간의 밀집도와 편의를 보이며 이러한 분포의 이상이 트레이닝 결과 추정되는 분산뿐만 아니라 분류 결과 자체에도 많은 영향을 준다. 본 연구에서는 트레이닝을 통해 추정된 분산의 특성과 이러한 특성이 화소값의 분포와 어떤 관련이 있는지를 규명하고, 그에 따른 분류결과의 변화에 대해 검토하였고, 분산 과소추정의 영향을 최소화할 수 있는 트레이닝 기법을 제시하였다.

• 한국데이터정보과학회:학술대회논문집
• /
• 한국데이터정보과학회 2003년도 춘계학술대회
• /
• pp.1-14
• /
• 2003

In man cases, the measurement error variances may be functions of the unknown true values or related covariate. In some cases, the measurement error variances increase in proportion to the value of predictor. This paper develops estimators of the parameters of a linear measurement error variance function under stratified multistage random sampling design and additional conditions. Also, this paper evaluates and compares the power of an asymptotically unbiased test with that of an asymptotically biased test. The proposed method are applied to blood sample measurements from the U.S. Third National Health and Nutrition Examination Survey(NHANES III)

• 대한가정학회지
• /
• 제44권4호
• /
• pp.49-63
• /
• 2006

The purpose of this study was to understand the character of career attitude according to the group type which was identified and measured by Q methodology. The subjects were 38 junior students attending hotel & food service culinary management at Kyungnam College of Information & Technology. For the study, 88 variances of Lee's career attitude were used. In the career attitude items, 26 variances of career attitude were selected by factor analysis. The 26 variances explained 70.44% of all variances. Twenty-six variances were used on Q sorting from which 9 group types were identified by SPSS window program, and these 9 occupied 75.627%n of all variance. The groups were classified into two parts extroversion and introversion. Four groups(1, 3, 6, and 9) were identified as extroversion, and 5 groups(2, 4, 5, 7, and 8) as introversion. Group 1 was explained 10.270% of all groups, group 2(14.352%), group 3(10.270%), group 4(7.527%), group 5(6.314%), group 6(5.726%), group 7(5.469%), group 8(5.006%), and group 9(4.145%). Group 1 was named as "active challenge type", group 2 as "passive consideration type", group 3 as "realistic leader type", group 4 as "conservative challenge oriented type", group 5 as "conservative harmony type", group 6 as "arbitrary plan oriented type", group 7 as "realistic stability type", group 8 as "conservative creation type" and group 9 as "conservative reality type".

• 한국전문물리치료학회지
• /
• 제22권3호
• /
• pp.23-32
• /
• 2015

The purpose of this study was to identify the effects of mechanical traction applied to the knee joint on pain, knee range of motion (ROM), timed up and go (TUG) and Western Ontario and MacMaster Universities Osteoarthritis (WOMAC) in patients with knee osteoarthritis (KOA) of Kellgren-Lawrence radiological rating scale II or III. Twenty three patients participated in the experiment for a period of four weeks. After baseline assessment, the patients with KOA were randomized into two groups: the traction group ($n_1=12$), which received traction with general physical therapy; and the control group ($n_2=11$), which received general physical therapy only on unilateral knee joints. Patients received interventions once a day, three times a week, for four weeks. Wilcoxon signed-rank test was used to analyze the change of dependent variances within the group during pre and post intervention. Mann-Whitney U test was used to analyze the change of dependent variances as TUG and passive ROM between the two groups. Analysis of covariance was used to analyze the change of dependent variances as numeric pain rating scale (NPRS) and WOMAC score between the two groups. In Wilcoxon signed-rank test, the traction group improved significantly with regard to NPRS (p<.01), passive knee flexion ROM (p<.01), passive knee extension (p<.05), TUG (p<.01) and WOMAC scores (p<.01) after intervention for four weeks, but not for the control group. In the Mann-Whitney U test and analysis of covariance, no significant difference was seen among all the dependent variances after intervention for four weeks between the two groups. These outcomes suggest that further studies should be carried out to determine the effects of mechanical traction prior to using it for the treatment of patients with knee osteoarthritis.

• 종양간호연구
• /
• 제12권3호
• /
• pp.204-212
• /
• 2012

Purpose: To investigate the effectiveness and variance of a critical pathway (CP) for laparoscopic colon resection in colon cancer patients, and nurses'satisfaction with the CP. Methods: A CP for laparoscopic colon resection was applied to the CP-group that included 50 patients, who underwent elective colon resection between March and May, 2011. The non-CP group included 51 patients who had the same operation without the CP applied from March to May, 2010. Results: The means of length of hospital stay were 11.7 and 7.3 days (p<.001) and the lengths of postoperative hospital stay were 8.6 and 5.1 days (p<.001) in the non-CP group and CP group, respectively. There was no significant difference between two groups for total healthcare costs, pain score, complications, or emergency room visits within 30 days after discharge. By examining variances of the CP, there were 162 variances and the most frequent cause was patient's condition. Nurses'satisfaction with the use of CP was favorable and the mean score of satisfaction was 3.76 on the 5 point Likert scale. Conclusion: There are clear benefits to use of CP, resulting in standardized and effective patient care. In conclusion, analysis of variance data can assist in evaluating and revising CP for optimal care and reducing variances.

• Nuclear Engineering and Technology
• /
• 제55권11호
• /
• pp.4228-4237
• /
• 2023

The Improved Deterministic Truncation of Monte Carlo (iDTMC) is a powerful acceleration and variance reduction scheme in the Monte Carlo analysis. The concept of the iDTMC method and correlated sampling-based real variance estimation are briefly introduced. Moreover, the application of the iterative scheme to the correlated sampling is discussed. The iDTMC method is utilized in a 3-dimensional small modular reactor (SMR) model problem. The real variances of burnup-dependent criticality and power distribution are evaluated and compared with the ones obtained from 30 independent iDTMC calculations. The impact of the inactive cycles on the correlated sampling is also evaluated to investigate the consistency of the correlated sample scheme. In addition, numerical performances and sensitivity analysis on the real variance estimation are performed in view of the figure of merit of the iDTMC method. The numerical results show that the correlated sampling accurately estimates the real variances with high computational efficiencies.