No abstract

No abstract

No abstract

Selective maintenance is widely used as a reliability-centered maintenance strategy due to the limited maintenance resources. However, existing selective maintenance studies only consider basic reliability, which cannot systematically describe the operating mechanism of a multistate system, thereby resulting in the inability to obtain an optimal maintenance strategy. Moreover, intelligent manufacturing systems are highly representative of typical multistate industrial systems. In this study, a mission reliability-oriented selective maintenance optimization model for intelligent manufacturing systems that considers the uncertain maintenance effect was proposed. First, a new connotation and modeling method for mission reliability based on multistate system theory was presented to comprehensively characterize the operating mechanism of intelligent manufacturing systems. Second, a quantitative model between maintenance resources and quality based on real-time data was established to reflect the uncertain characteristics caused by repairmen and tools. Third, a selective maintenance decision model of a multistate manufacturing system was developed under the constraints of maintenance cost and time. This constraint combination optimization problem was solved using the particle swarm optimization algorithm. Finally, a case study of selective maintenance optimization for a cylinder head manufacturing system was presented to verify the proposed method.

Aim To evaluate the clinical efficacy of Human Urinary kallidinogenase ( HUK ) in the treatment of acute ischemic stroke ( AIS ) patients with level 3 hypertension. Methods In this retrospective study, from January 2015 to June 2016, 150 consecutive AIS patients were registered in our database. Among them, 47 with level 3 hypertension received either HUK treatment ( HUK group, 22 cases) or basic treatment (control group, 25 cases). Basic treatment was administrated on all patients. 0.15 PNA unit of HUK injection plus 100 ml saline in intravenous infusion was performed in the HUK group, with once a day for 14 consecutive days. The modified Rankin Scale ( mRS ) scores in two groups were analyzed 3 months after the treatment. Results No difference was found in the NIHSS scores, age, gender, and comorbidities between two groups before treatment ( p > .05). While after treatment, 3‐month mRS score was significantly lower in the HUK group (2.1 ± 1.4 vs. 3.1 ± 1.3, p = .012) and good recovery rate (3‐month mRS score ≤2) in the HUK group was significantly higher than that in the control group ( p < .05). Conclusion HUK is able to promote long‐term recovery for AIS patients with level 3 hypertension remarkably.