Objective: The aim of this study was to explore the modified physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) scoring system and the relationship between predicted dat...Objective: The aim of this study was to explore the modified physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) scoring system and the relationship between predicted data and actual data of complication and surgical mortality of lung cancer radical surgery made by such score system. Methods: Retrospective analysis on the 86 cases of the clinical materials of patients with primary lung cancer radical surgery for thoracic surgery of line lung cancer in the 81st Hospital of PLA from October 2010 to October 2011 and using the POSSUM scoring system to predict the cases of postoperative complication and death toll, then making a comparison with the actual cases. Results: The POSSUM scoring system predicting 29 cases of postoperative complications, but 32 cases of practical complications, the difference between them has no statistical significance (P﹥0.05), 8 cases of predicted postoperative deaths, 2 cases of practical deaths, by comparison, there was statistical significance (P﹤0.05). Conclusion: The modified POSSUM scoring system can be used to predict the postoperative complication of lung surgery patients, but sometimes overestimates the postoperative death cases.展开更多
This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical propertie...This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical properties are examined and a comprehensive set of diagnostic checks are made on the two decades of AAPL daily stock returns. Combing the Extreme Value Approach together with a statistical analysis, it is learnt that the lowest VaR occurs on Fridays and Mondays typically. Moreover, high Q4 and Q3 VaR are observed during the test period. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in AAPL. Moreover, this methodology, which is applicable to any other stocks or portfolios, is more realistic and comprehensive than the standard normal distribution based VaR model that is commonly used.展开更多
A microgrid is a combination of distributed energy resources and controllable loads. The main objective of this research is to optimize energy flow within a microgrid with regards to reliability in grid connected mode...A microgrid is a combination of distributed energy resources and controllable loads. The main objective of this research is to optimize energy flow within a microgrid with regards to reliability in grid connected mode. A microgrid with combined heat and power, natural gas generator, diesel generator, solar energy, wind energy, and battery energy storage along with a critical load is considered in this research. An event oriented analytical method called FTA （fault trees analysis） is implemented for reliability optimization using PTC Windchill Solutions software in a microgrid. The reliability of each component in each energy source of the microgrid is calculated using FTA. The reliability of the critical load is evaluated. The quantitative and qualitative results of FTA are evaluated in order to interpret the results of fault tree. The sensitivity and uncertainty of the fault tree results for critical load is deduced by calculating the importance measures such as risk achievement worth, risk reduction worth, criticality importance and Fussel-Vesely importance. Finally from the results the components that are sensitive and at high risk are deduced.展开更多
This paper aims to propose ERT （Expected Reaching Time）, a new risk adverse evaluation criterion of finite multiplication processes, and to examine its properties in relation to the dominance criterion. The ERT mean...This paper aims to propose ERT （Expected Reaching Time）, a new risk adverse evaluation criterion of finite multiplication processes, and to examine its properties in relation to the dominance criterion. The ERT means the expected time that takes for an objective valiable to reach a target value. To deal with the environmental risk involved in the process, the expectation maximizing strategy may be the most well known. However, for many cases the dominance strategy rather than the expectation maximizing strategy is adopted and works very well. In this paper we first prove rigorously that minimization of the ERT is equivalent to the dominance criterion in the infinite period. Then we demonstrate by simulation that the ERT gives almost equal evaluation as the dominance criterion even for the finite multiplications, after showing that it is approximately proportional to the logarithm of the target value.展开更多
文摘Objective: The aim of this study was to explore the modified physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) scoring system and the relationship between predicted data and actual data of complication and surgical mortality of lung cancer radical surgery made by such score system. Methods: Retrospective analysis on the 86 cases of the clinical materials of patients with primary lung cancer radical surgery for thoracic surgery of line lung cancer in the 81st Hospital of PLA from October 2010 to October 2011 and using the POSSUM scoring system to predict the cases of postoperative complication and death toll, then making a comparison with the actual cases. Results: The POSSUM scoring system predicting 29 cases of postoperative complications, but 32 cases of practical complications, the difference between them has no statistical significance (P﹥0.05), 8 cases of predicted postoperative deaths, 2 cases of practical deaths, by comparison, there was statistical significance (P﹤0.05). Conclusion: The modified POSSUM scoring system can be used to predict the postoperative complication of lung surgery patients, but sometimes overestimates the postoperative death cases.
文摘This study investigates calendar anomalies： day-of-the-week effect and seasonal effect in the Value-at-Risk （VaR） analysis of stock returns for AAPL during the period of 1995 through 2015. The statistical properties are examined and a comprehensive set of diagnostic checks are made on the two decades of AAPL daily stock returns. Combing the Extreme Value Approach together with a statistical analysis, it is learnt that the lowest VaR occurs on Fridays and Mondays typically. Moreover, high Q4 and Q3 VaR are observed during the test period. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in AAPL. Moreover, this methodology, which is applicable to any other stocks or portfolios, is more realistic and comprehensive than the standard normal distribution based VaR model that is commonly used.
文摘A microgrid is a combination of distributed energy resources and controllable loads. The main objective of this research is to optimize energy flow within a microgrid with regards to reliability in grid connected mode. A microgrid with combined heat and power, natural gas generator, diesel generator, solar energy, wind energy, and battery energy storage along with a critical load is considered in this research. An event oriented analytical method called FTA （fault trees analysis） is implemented for reliability optimization using PTC Windchill Solutions software in a microgrid. The reliability of each component in each energy source of the microgrid is calculated using FTA. The reliability of the critical load is evaluated. The quantitative and qualitative results of FTA are evaluated in order to interpret the results of fault tree. The sensitivity and uncertainty of the fault tree results for critical load is deduced by calculating the importance measures such as risk achievement worth, risk reduction worth, criticality importance and Fussel-Vesely importance. Finally from the results the components that are sensitive and at high risk are deduced.
文摘This paper aims to propose ERT （Expected Reaching Time）, a new risk adverse evaluation criterion of finite multiplication processes, and to examine its properties in relation to the dominance criterion. The ERT means the expected time that takes for an objective valiable to reach a target value. To deal with the environmental risk involved in the process, the expectation maximizing strategy may be the most well known. However, for many cases the dominance strategy rather than the expectation maximizing strategy is adopted and works very well. In this paper we first prove rigorously that minimization of the ERT is equivalent to the dominance criterion in the infinite period. Then we demonstrate by simulation that the ERT gives almost equal evaluation as the dominance criterion even for the finite multiplications, after showing that it is approximately proportional to the logarithm of the target value.
