研究了航班地面等待模型中延误成本的计算问题。建立了单元受限地面等待问题的数学模型,分析了航班延误成本的构成,给出了航班延误显性成本的计算方法,并将其应用于数学模型中目标函数的计算。最后,用分段排序和定步长排序对模型进行了...研究了航班地面等待模型中延误成本的计算问题。建立了单元受限地面等待问题的数学模型,分析了航班延误成本的构成,给出了航班延误显性成本的计算方法,并将其应用于数学模型中目标函数的计算。最后,用分段排序和定步长排序对模型进行了仿真,并与先到先服务(F irst com e,first served,FCFS)排序进行了比较。仿真结果表明,对航班延误成本进行定量分析,能够更有效地控制航班延误的地面等待成本。展开更多
Background The socio-economic burden of acute exacerbation of chronic obstructive pulmonary disease （AECOPD） in Beijing is not fully understood. The study investigated the hospitalization cost in patients with AECOP...Background The socio-economic burden of acute exacerbation of chronic obstructive pulmonary disease （AECOPD） in Beijing is not fully understood. The study investigated the hospitalization cost in patients with AECOPD and the associated factors. Methods A multi-center, retrospective study was conducted in the four hospitals in Beijing including two level III hospitals and two level II hospitals. Patients with AECOPD admitted to the hospitals between January and December in 2006 were enrolled. The hospitalization cost and its relationship with disease severity and treatment were analyzed. Results Totally 439 patients were enrolled with 294 men （67.0%） and a mean age 73.4 years. The mean hospital stay was 20.7 days. A total of 204 patients （46.5%） had respiratory failure, 153 （34.9%） with cor pulmonale, 123 （28.0%） with coronary artery disease, 231 （52.6%） with hypertension, 70 （15.9%） with cerebrovascular disease and 32 （7.3%） with renal failure. The percentage of drug cost to total cost was the highest （71.2%）, followed by laboratory cost （16.7%）, therapy cost （9.7%）, oxygen cost （7.3%）, radiology cost （4.5%）, examination cost （4.5%）, bed cost （4.1%）. Correlation analysis showed that cost was positively correlated with age, hospitalization days, co-morbidities such as respiratory failure and cor pulmonale, hypertension. Three hundred and twenty-one patients were further analyzed. The hospitalization cost increased in patients with non-invasive ventilation （P〈0.01）, invasive mechanical ventilation （P〈0.01）, ICU stay （P〈0.01）, antibiotics （P〈0.05）, systemic steroids （P〈0.01）, and poor prognosis （P〈0.05）. Correlation analysis showed that the hospitalization cost was negatively correlated with percentage forced expiratory volume in 1 second （FEV1%） （r=-0.149, P〈0.05）, pH （r=-0.258, P〈0.01）, and PaO2 （r=-0.131, P〈0.05）, positively correlated with PaCO2 （r=0.319, P〈0.01）, non-invasive positive pres展开更多
文摘研究了航班地面等待模型中延误成本的计算问题。建立了单元受限地面等待问题的数学模型,分析了航班延误成本的构成,给出了航班延误显性成本的计算方法,并将其应用于数学模型中目标函数的计算。最后,用分段排序和定步长排序对模型进行了仿真,并与先到先服务(F irst com e,first served,FCFS)排序进行了比较。仿真结果表明,对航班延误成本进行定量分析,能够更有效地控制航班延误的地面等待成本。
文摘Background The socio-economic burden of acute exacerbation of chronic obstructive pulmonary disease （AECOPD） in Beijing is not fully understood. The study investigated the hospitalization cost in patients with AECOPD and the associated factors. Methods A multi-center, retrospective study was conducted in the four hospitals in Beijing including two level III hospitals and two level II hospitals. Patients with AECOPD admitted to the hospitals between January and December in 2006 were enrolled. The hospitalization cost and its relationship with disease severity and treatment were analyzed. Results Totally 439 patients were enrolled with 294 men （67.0%） and a mean age 73.4 years. The mean hospital stay was 20.7 days. A total of 204 patients （46.5%） had respiratory failure, 153 （34.9%） with cor pulmonale, 123 （28.0%） with coronary artery disease, 231 （52.6%） with hypertension, 70 （15.9%） with cerebrovascular disease and 32 （7.3%） with renal failure. The percentage of drug cost to total cost was the highest （71.2%）, followed by laboratory cost （16.7%）, therapy cost （9.7%）, oxygen cost （7.3%）, radiology cost （4.5%）, examination cost （4.5%）, bed cost （4.1%）. Correlation analysis showed that cost was positively correlated with age, hospitalization days, co-morbidities such as respiratory failure and cor pulmonale, hypertension. Three hundred and twenty-one patients were further analyzed. The hospitalization cost increased in patients with non-invasive ventilation （P〈0.01）, invasive mechanical ventilation （P〈0.01）, ICU stay （P〈0.01）, antibiotics （P〈0.05）, systemic steroids （P〈0.01）, and poor prognosis （P〈0.05）. Correlation analysis showed that the hospitalization cost was negatively correlated with percentage forced expiratory volume in 1 second （FEV1%） （r=-0.149, P〈0.05）, pH （r=-0.258, P〈0.01）, and PaO2 （r=-0.131, P〈0.05）, positively correlated with PaCO2 （r=0.319, P〈0.01）, non-invasive positive pres
