How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is ...How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.展开更多
<strong>Background:</strong> <span style="font-family:Verdana;">In-hospital mortality is high in low-income countries. Currently, little is known in Cameroon concerning the characteristics ...<strong>Background:</strong> <span style="font-family:Verdana;">In-hospital mortality is high in low-income countries. Currently, little is known in Cameroon concerning the characteristics of patients who die in cardiology units. Our objectives were to determine the in-hospital mortality rate;describe </span><span style="font-family:Verdana;">th</span><span style="font-family:;" "=""><span style="font-family:Verdana;">e general characteristics of death patients, and factors associated with mortality. </span><b><span style="font-family:Verdana;">Material and Methods: </span></b><span style="font-family:Verdana;">We conducted a retrospective cross-sectional study by reviewing the medical records of all patients admitted to the cardiology unit of the Yaoundé Central Hospital (CHY) between January 2018 </span></span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;">January 2019. The files of all death patients were studied for socio-demographical, clinical and therapeutical variables. Bivariate analysis was conducted to order to check the association between independents variables and time of death. A p-value <</span><span style="font-family:Verdana;"> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">0.05 was considered statistically significant. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">A total number of 860 patients were admitted in the cardiology unit of CHY during the study period. Amongst the 860 patients admitted 78 had a fatal outcome, hence, an in-hospital mortality rate of 9.06%. The male gender was predominant amongst the deceased patients (n = 45). The mean age at death was 69 ± 15.19 years. The median time before death was 6 days and they ranged between 1 to 25 days. Hypertension was the most frequent comorbidity (65.4%). Stroke was the principal cause of admission (40.3%), whereas the main presenting complaint was dyspnea (26.9%). Before being admitted to the cardiology department, the majority of the deceased patients were from the emergency department. The major clinical sign of death was respiratory distress (39.74%). Shock on admission was the sole factor found to be associated with the mean time of death (p = 0.012). The patient</span></span><span style="font-family:Verdana;">s</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> with deep venous thrombosis compared to other diagnoses were less like to die early (r = 16, p = 0.016). </span><b><span style="font-family:Verdana;">Conclusion: </span></b><span style="font-family:Verdana;">The patient admitted in the cardiology unit of Yaoundé Central Hospital died mainly from stroke and the death is earlier when the patient has signs of shock on admission. These results emphasize the need for a good primary evaluation at the emergency room, to better manage patients with cardiovascular diseases in the cardiology ward.</span></span>展开更多
基金supported by the National Natural Science Foundation of China(51075060)
文摘How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.
文摘<strong>Background:</strong> <span style="font-family:Verdana;">In-hospital mortality is high in low-income countries. Currently, little is known in Cameroon concerning the characteristics of patients who die in cardiology units. Our objectives were to determine the in-hospital mortality rate;describe </span><span style="font-family:Verdana;">th</span><span style="font-family:;" "=""><span style="font-family:Verdana;">e general characteristics of death patients, and factors associated with mortality. </span><b><span style="font-family:Verdana;">Material and Methods: </span></b><span style="font-family:Verdana;">We conducted a retrospective cross-sectional study by reviewing the medical records of all patients admitted to the cardiology unit of the Yaoundé Central Hospital (CHY) between January 2018 </span></span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;">January 2019. The files of all death patients were studied for socio-demographical, clinical and therapeutical variables. Bivariate analysis was conducted to order to check the association between independents variables and time of death. A p-value <</span><span style="font-family:Verdana;"> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">0.05 was considered statistically significant. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">A total number of 860 patients were admitted in the cardiology unit of CHY during the study period. Amongst the 860 patients admitted 78 had a fatal outcome, hence, an in-hospital mortality rate of 9.06%. The male gender was predominant amongst the deceased patients (n = 45). The mean age at death was 69 ± 15.19 years. The median time before death was 6 days and they ranged between 1 to 25 days. Hypertension was the most frequent comorbidity (65.4%). Stroke was the principal cause of admission (40.3%), whereas the main presenting complaint was dyspnea (26.9%). Before being admitted to the cardiology department, the majority of the deceased patients were from the emergency department. The major clinical sign of death was respiratory distress (39.74%). Shock on admission was the sole factor found to be associated with the mean time of death (p = 0.012). The patient</span></span><span style="font-family:Verdana;">s</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> with deep venous thrombosis compared to other diagnoses were less like to die early (r = 16, p = 0.016). </span><b><span style="font-family:Verdana;">Conclusion: </span></b><span style="font-family:Verdana;">The patient admitted in the cardiology unit of Yaoundé Central Hospital died mainly from stroke and the death is earlier when the patient has signs of shock on admission. These results emphasize the need for a good primary evaluation at the emergency room, to better manage patients with cardiovascular diseases in the cardiology ward.</span></span>
