This paper proposes a joint inspection-based maintenance and spare ordering optimization policy that considers the problem of integrated inspection,preventive maintenance,spare ordering,and quality control for a four-...This paper proposes a joint inspection-based maintenance and spare ordering optimization policy that considers the problem of integrated inspection,preventive maintenance,spare ordering,and quality control for a four-state single-unit manufacturing system.When an inspection detects a minor defect,a second phase inspection is initiated and a regular order is placed.Product quality begins to deteriorate when the system undergoes a severe defect.To counter this,an advanced replacement of the minor defective system is carried out at the Jth second phase inspection.If a severe defect is recognized prior to the Jth inspection,or if system failure occurs,preventive or corrective replacement is executed.The timeliness of replacement depends on the availability of spare.We adopt two modes of ordering:a regular order and an emergency order.Meanwhile,a threshold level is introduced to determine whether an emergency order is preferred even when the regular order is already ordered but has not yet arrived.The optimal joint inspection-based maintenance and spare ordering policy is formulated by minimizing the expected cost per unit time.A simulation algorithm is proposed to obtain the optimal two-phase inspection interval,threshold level and advanced replacement interval.Results from several numerical examples demonstrate that,in terms of the expected cost per unit time,our proposed model is superior to some existing models.展开更多
Background:Parkinson’s disease is a progressive neurodegenerative disease,and is usually treated with levodopa combined with dopa decarboxylase inhibitor like Madopar.In order to improve the efficacy and reduce adver...Background:Parkinson’s disease is a progressive neurodegenerative disease,and is usually treated with levodopa combined with dopa decarboxylase inhibitor like Madopar.In order to improve the efficacy and reduce adverse reactions,Chinese herbal medicines are usually applied with Madopar to treat Parkinson’s disease in clinic.According to the results of certain randomized controlled trials,levodopa drugs combined with Chinese herbal medicines could achieve better effects like the improvement of clinical symptoms,the reduced incidence of adverse reactions,and the reduced dose of levodopa drugs(especially in the maintenance phase).However,not all the randomized controlled trials showed favorable effect on Parkinson’s disease.Therefore,it is necessary to find out how to effectively combine Chinese herbal medicines with Madopar.In order to evaluate the effects of Chinese herbal medicines on Madopar dose and adverse reaction during the maintenance phase of Parkinson’s disease,a meta-analysis was conducted.Methods:A systematic research was carried out for randomized controlled trials of combined Chinese herbal medicines and Madopar treatment for Parkinson’s disease during the maintenance phase published till August 2019.The primary outcome was the Madopar dose and secondary outcome was the incidence of adverse reaction.Data were pooled and analyzed with RevMan 5.3.Results:A total of 18 studies were included with 1,169 cases.However,study quality evaluation showed low methodological quality.Meta-analyses showed that the dose of Madopar in the treatment group was significantly lower than that in the control group,and the incidence of adverse reactions in the treatment group was also significantly lower than that in the control group.However,the correlation analysis showed that the reduction of Madopar dose was not related to the reduction of incidence of adverse reactions(P>0.05).There existed publication bias on the primary outcome and secondary outcome.Conclusions:Chinese herbal medicines could reduce the Madop展开更多
基金This work was supported by the National Natural Science Foundation of China(71471015)the Social Science Fund Base Project of Beijing(19JDGLA001).
文摘This paper proposes a joint inspection-based maintenance and spare ordering optimization policy that considers the problem of integrated inspection,preventive maintenance,spare ordering,and quality control for a four-state single-unit manufacturing system.When an inspection detects a minor defect,a second phase inspection is initiated and a regular order is placed.Product quality begins to deteriorate when the system undergoes a severe defect.To counter this,an advanced replacement of the minor defective system is carried out at the Jth second phase inspection.If a severe defect is recognized prior to the Jth inspection,or if system failure occurs,preventive or corrective replacement is executed.The timeliness of replacement depends on the availability of spare.We adopt two modes of ordering:a regular order and an emergency order.Meanwhile,a threshold level is introduced to determine whether an emergency order is preferred even when the regular order is already ordered but has not yet arrived.The optimal joint inspection-based maintenance and spare ordering policy is formulated by minimizing the expected cost per unit time.A simulation algorithm is proposed to obtain the optimal two-phase inspection interval,threshold level and advanced replacement interval.Results from several numerical examples demonstrate that,in terms of the expected cost per unit time,our proposed model is superior to some existing models.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2019A1515010644)Major Research and Development Program of Shandong Province,China(2018GSF118149)Project of Traditional Chinese Medicine Bureau of Guangdong Province(No.20201073).
文摘Background:Parkinson’s disease is a progressive neurodegenerative disease,and is usually treated with levodopa combined with dopa decarboxylase inhibitor like Madopar.In order to improve the efficacy and reduce adverse reactions,Chinese herbal medicines are usually applied with Madopar to treat Parkinson’s disease in clinic.According to the results of certain randomized controlled trials,levodopa drugs combined with Chinese herbal medicines could achieve better effects like the improvement of clinical symptoms,the reduced incidence of adverse reactions,and the reduced dose of levodopa drugs(especially in the maintenance phase).However,not all the randomized controlled trials showed favorable effect on Parkinson’s disease.Therefore,it is necessary to find out how to effectively combine Chinese herbal medicines with Madopar.In order to evaluate the effects of Chinese herbal medicines on Madopar dose and adverse reaction during the maintenance phase of Parkinson’s disease,a meta-analysis was conducted.Methods:A systematic research was carried out for randomized controlled trials of combined Chinese herbal medicines and Madopar treatment for Parkinson’s disease during the maintenance phase published till August 2019.The primary outcome was the Madopar dose and secondary outcome was the incidence of adverse reaction.Data were pooled and analyzed with RevMan 5.3.Results:A total of 18 studies were included with 1,169 cases.However,study quality evaluation showed low methodological quality.Meta-analyses showed that the dose of Madopar in the treatment group was significantly lower than that in the control group,and the incidence of adverse reactions in the treatment group was also significantly lower than that in the control group.However,the correlation analysis showed that the reduction of Madopar dose was not related to the reduction of incidence of adverse reactions(P>0.05).There existed publication bias on the primary outcome and secondary outcome.Conclusions:Chinese herbal medicines could reduce the Madop
