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In this study, system maintenance and production scheduling are jointly decided to solve the problems of resource idleness and time cost increase due to system maintenance in the processing of production scheduling. For the multi-component system with economic dependence, a joint strategy of condition-based maintenance and production scheduling is formulated, which includes opportunistic maintenance, preventive maintenance, and corrective maintenance. On this basis, a joint decision model is established to minimise the total weighted expected completion time. Subsequently, all possible maintenance requirements and their corresponding probabilities for the multi-component system in the entire production scheduling process are deduced via the deterioration state space partition modelling method. Furthermore, the stationary probability density function of the joint state of the system is derived, and its numerical solution method is provided. Finally, taking the KS5 adjustable multi-axis tapping machine as an example, numerical experiments are conducted to verify the efficacy of the proposed strategy and the established model. Comparisons with previous strategies using different numbers of components and scheduling job scales indicate that the joint decision model yields better results. [ABSTRACT FROM AUTHOR]

The joint optimization of condition-based opportunistic maintenance and (0,1)-type spare part inventory policy is investigated for a two-component system. Deterioration state-space partitioning (DSSP) of the observed state and the spare part inventory state is developed to analyze all the possible maintenance requirements of the system and calculate the probabilities of the actual maintenance activities with the restriction of the inventory state, as well as the probabilities of ordering and holding of spare parts. An expression of the stationary law of the joint state and its numeric solution are deduced based on an analysis of all the possible transitions of the joint state during an inspection cycle. Further, an expected long-run cost rate model of the operation of the system under the proposed policy was developed to determine the optimal joint strategy which involved a semi-regenerative process theory. Finally, numerical experiments were performed. [ABSTRACT FROM AUTHOR]

Background: Low-dose aspirin can reduce the incidence of preeclampsia and intrauterine growth restriction (IUGR). However, the effects of ethnicity upon low-dose aspirin's efficacy has not been analyzed. Here, we comparatively evaluated the efficacy of low-dose aspirin in preventing preeclampsia and related fetal complications in East Asian and non-East Asian pregnant women at risk for preeclampsia.Methods: Several databases were searched for randomized controlled trials (RCTs) comparing low-dose aspirin with either placebo or no treatment in pregnant women at risk for preeclampsia. Odds ratios (ORs) and associated 95% confidence intervals (CIs) for preeclampsia and related fetal outcomes were tabulated.Results: Low-dose aspirin significantly reduced preeclampsia risk in both East Asians (OR = 0.20, 95% CI: 0.11-0.35) and non-East Asians (OR = 0.84, 95% CI: 0.77-0.92). Low-dose aspirin significantly reduced IUGR risk in East Asians (OR = 0.36, 95% CI: 0.20-0.67) but not in non-East Asians (OR = 0.85, 95% CI: 0.41-1.77). Low-dose aspirin did not significantly reduce the risk of cesarean section in either East Asians (OR = 0.67, 95% CI: 0.14-3.22) or non-East Asians (OR = 1.01, 95% CI: 0.86-1.19).Conclusions: Low-dose aspirin is effective in reducing preeclampsia risk in both East Asians and non-East Asians and has differential effects in East Asians and non-East Asians with respect to IUGR. [ABSTRACT FROM AUTHOR]