For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve th...For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve the precision of the system reliability assessment. If the multi-level pass/fail data are overlapping,one challenging problem for the Bayesian analysis is to develop a likelihood function. Since the computation burden of the existing methods makes them infeasible for multi-component systems, this paper proposes an improved Bayesian approach for the system reliability assessment in light of overlapping data. This approach includes three steps： fristly searching for feasible paths based on the binary decision diagram, then screening feasible points based on space partition and constraint decomposition, and finally simplifying the likelihood function. An example of a satellite rolling control system demonstrates the feasibility and the efficiency of the proposed approach.展开更多
This article provides a snapshot of pass/fail and discretionary grading approaches, highlighting the advantages and disadvantages of each. Norm-referenced and criterion-referenced grading practices and their associati...This article provides a snapshot of pass/fail and discretionary grading approaches, highlighting the advantages and disadvantages of each. Norm-referenced and criterion-referenced grading practices and their associations with learning are identified. A brief historical backdrop illustrates how grading practices have evolved. The inherent subjectivity of grading is emphasized. Pass/fail grading supports intrinsic motivation and self-direction, but limits opportunities for recognizing excelling students. Discretionary grading, which includes letter (F- to A+) and numeric (0% to 100%) representations, supports extrinsic motivation and self-improvement, but promotes unhealthy competition. Both approaches have merit and can effectively measure student achievement in nursing education programs.展开更多
设有成败型元件A_i(i=1,2,…,K)组成的并联系统M,设第i个元件可靠性P_i,P_i未知(i=1,2,…,K)。系统可靠性R=1-sum from i=1 to K (1-P_i)亦未知。 设对第i个元件进行了n_i次独立试验,但对其每次试验结果是成功还是失败要先通过某检测仪...设有成败型元件A_i(i=1,2,…,K)组成的并联系统M,设第i个元件可靠性P_i,P_i未知(i=1,2,…,K)。系统可靠性R=1-sum from i=1 to K (1-P_i)亦未知。 设对第i个元件进行了n_i次独立试验,但对其每次试验结果是成功还是失败要先通过某检测仪器检测判断,设检测正确率为r_i,r_i为已知,且设ri>1/2。设对第i个元件,试验R_i次,试验结果经检测被判为成功的次数是s_i(真正的成功数并不知道)(i=1,2,…,K),本文讨论基于诸元件的数组(n_i,s_i,r_i)(i=1,2,…,K),求原并联系统M的可靠性R=1-sum from i=1 to K(1-P_i)的Bootstrap置信下限的问题。展开更多
基金supported by the National Natural Science Foundation of China(61304218)
文摘For high reliability and long life systems, system pass/fail data are often rare. Integrating lower-level data, such as data drawn from the subsystem or component pass/fail testing,the Bayesian analysis can improve the precision of the system reliability assessment. If the multi-level pass/fail data are overlapping,one challenging problem for the Bayesian analysis is to develop a likelihood function. Since the computation burden of the existing methods makes them infeasible for multi-component systems, this paper proposes an improved Bayesian approach for the system reliability assessment in light of overlapping data. This approach includes three steps： fristly searching for feasible paths based on the binary decision diagram, then screening feasible points based on space partition and constraint decomposition, and finally simplifying the likelihood function. An example of a satellite rolling control system demonstrates the feasibility and the efficiency of the proposed approach.
文摘This article provides a snapshot of pass/fail and discretionary grading approaches, highlighting the advantages and disadvantages of each. Norm-referenced and criterion-referenced grading practices and their associations with learning are identified. A brief historical backdrop illustrates how grading practices have evolved. The inherent subjectivity of grading is emphasized. Pass/fail grading supports intrinsic motivation and self-direction, but limits opportunities for recognizing excelling students. Discretionary grading, which includes letter (F- to A+) and numeric (0% to 100%) representations, supports extrinsic motivation and self-improvement, but promotes unhealthy competition. Both approaches have merit and can effectively measure student achievement in nursing education programs.
文摘设有成败型元件A_i(i=1,2,…,K)组成的并联系统M,设第i个元件可靠性P_i,P_i未知(i=1,2,…,K)。系统可靠性R=1-sum from i=1 to K (1-P_i)亦未知。 设对第i个元件进行了n_i次独立试验,但对其每次试验结果是成功还是失败要先通过某检测仪器检测判断,设检测正确率为r_i,r_i为已知,且设ri>1/2。设对第i个元件,试验R_i次,试验结果经检测被判为成功的次数是s_i(真正的成功数并不知道)(i=1,2,…,K),本文讨论基于诸元件的数组(n_i,s_i,r_i)(i=1,2,…,K),求原并联系统M的可靠性R=1-sum from i=1 to K(1-P_i)的Bootstrap置信下限的问题。
