Background: Patients with generalized anxiety disorder (GAD) are among the highest users of healthcare resources. The broadening of the DSM-IV criteria for GAD has been a subject of controversy in the literature, but ...Background: Patients with generalized anxiety disorder (GAD) are among the highest users of healthcare resources. The broadening of the DSM-IV criteria for GAD has been a subject of controversy in the literature, but its consequences have not been analyzed to date. Objective: The purpose of this study was to analyze how the broadening of the DSM-IV criteria affects healthcare resource utilization and related costs. Methods: A multicentre, prospective, observational study was conducted in randomly selected outpatient psychiatric clinics between October 2007 and April 2008. Patients diagnosed according to DSM-IV or broader criteria (1 month of excessive or non-excessive worry and only 2 associated DSM-IV symptoms) for the first time were consecutively enrolled. Socio-demographic data, healthcare resources and corresponding costs were collected over a 6-month period. Results: A total of 3549 patients were systematically recruited, 1815 in the DSM-IV criteria group (DG) and1264 inthe broad criteria group (BG). Treatments prescribed were similar for antidepressants in both groups (77.0% in the DG vs. 75.3% in the BG, p = 0.284), and slightly higher in the DG for benzodiazepines (71.5% vs. 67.2% respectively, p = 0.011) and anticonvulsants (72.1% vs. 67.0% respectively, p = 0.002). Healthcare resource utilization was statistically reduced to a similar extent in both groups as a consequence of treatment, yielding a reduction in the cost of illness of €1196 (SD = 1158) and €1112 (SD = 874) respectively;p = 0.304, over a 6-month period. Conclusion: The broadening of the GAD criteria could lead to earlier diagnosis not necessarily associated with an increase in healthcare resource utilization or costs to the National Health System in the six-month follow-up.展开更多
According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is es...According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is established and a new adaptive robust guaranteed cost controller （AGCC） is proposed in this paper. First, the uncertain parameters of the system are estimated by using the adaptive method, then the estimated uncertain parameters and robust guaranteed cost control method are used to design a state feedback controller. The controller s feedback gain is obtained by solving a set of linear matrix inequality （LMI） constraints, such that the controller can meet a quadratic performance evaluation criterion. The simulation results show that we can realize the goal of maximum wind energy capture in low wind speed by the optimal torque control and constant power control in high wind speed by variable pitch control with good dynamic characteristics, robustness and the ability of suppressing disturbance.展开更多
In this present paper, an inventory model with a generalised exponential decreasing demand is considered. A numerical example is used to illustrate the application of the model. Sensitivity analysis of the optimal sol...In this present paper, an inventory model with a generalised exponential decreasing demand is considered. A numerical example is used to illustrate the application of the model. Sensitivity analysis of the optimal solution with respect to various parameters is carried out to see the effect of parameter changes on the solution.展开更多
This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programmin...This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programming and convex theory,the generalized directional derivative of the general multicommodity minimal cost flow problems is derived.The global convergence and superlinear convergence rate of the proposed algorithm are established under some mild conditions.展开更多
The maintenance model of simple repairable system is studied.We assume that there are two types of failure,namely type Ⅰ failure(repairable failure)and type Ⅱ failure(irrepairable failure).As long as the type Ⅰ fai...The maintenance model of simple repairable system is studied.We assume that there are two types of failure,namely type Ⅰ failure(repairable failure)and type Ⅱ failure(irrepairable failure).As long as the type Ⅰ failure occurs,the system will be repaired immediately,which is failure repair(FR).Between the(n-1)th and the nth FR,the system is supposed to be preventively repaired(PR)as the consecutive working time of the system reaches λ^(n-1) T,where λ and T are specified values.Further,we assume that the system will go on working when the repair is finished and will be replaced at the occurrence of the Nth type Ⅰ failure or the occurrence of the first type Ⅱ failure,whichever occurs first.In practice,the system will degrade with the increasing number of repairs.That is,the consecutive working time of the system forms a decreasing generalized geometric process(GGP)whereas the successive repair time forms an increasing GGP.A simple bivariate policy(T,N)repairable model is introduced based on GGP.The alternative searching method is used to minimize the cost rate function C(N,T),and the optimal(T,N)^(*) is obtained.Finally,numerical cases are applied to demonstrate the reasonability of this model.展开更多
The study of the development cost of general aviation aircraft is limited by small samples with many cost-driven factors. This paper investigates a parametric modeling method for prediction of the development cost of ...The study of the development cost of general aviation aircraft is limited by small samples with many cost-driven factors. This paper investigates a parametric modeling method for prediction of the development cost of general aviation aircraft. The proposed technique depends on some principal components, acquired by utilizing P value analysis and gray correlation analysis. According to these principal components, the corresponding linear regression and BP neural network models are established respectively. The feasibility and accuracy of the P value analysis are verified by comparing results of model fitting and prediction. A sensitivity analysis related to model precision and suitability is discussed in detail. Results obtained in this study show that the proposed method not only has a certain degree of versatility, but also provides a preliminary prediction of the development cost of general aviation aircraft.展开更多
Background: Serum level of cholesterol is one of the most vital risk factors for cardiovascular diseases (CVD). Statins are highly effective drugs for reducing serum cholesterol;hence, preventing coronary heart diseas...Background: Serum level of cholesterol is one of the most vital risk factors for cardiovascular diseases (CVD). Statins are highly effective drugs for reducing serum cholesterol;hence, preventing coronary heart disease (CHD). Rosuvastatin (Crestor) is one of the most potent and widely prescribed statins. Even though generic statins have been approved based on their bioequivalence with brand-name drugs, there remains considerable concern as regards their effectiveness and safety. Most clinicians and patients welcome the generic drug decreased costs;however, it is indispensable for them that effectiveness and safety are not compromised. Thus, the rationale intended for this study is to compare brand rosuvastatin and generic rosuvastatin as regard their economic impact using a cost-minimization analysis. Methods: This cost-minimization model estimates potential impact of rosuvastatin brand versus generic on the healthcare resource utilization for one-year frame from the payer perspective. The model conforms to real practice of management of hyperlipidemia in Egypt and was validated by experts. Results: The drug costs in the rosuvastatin brand group were 3,155,250 EGP while in the generic group were 2,299,030 EGP. The costs of CVD events in the rosuvastatin brand group were 5,863,558 EGP, while in the generic group were 6,810,180 EGP. The total costs in the rosuvastatin brand group were 9,018,808 EGP, while in the generic group were 9,109,210 EGP with a difference of −100,047 EGP. Conclusions: In conclusion, the real cost of generic treatment is more than that of the brand statin when taking into consideration the cardiovascular events.展开更多
文摘Background: Patients with generalized anxiety disorder (GAD) are among the highest users of healthcare resources. The broadening of the DSM-IV criteria for GAD has been a subject of controversy in the literature, but its consequences have not been analyzed to date. Objective: The purpose of this study was to analyze how the broadening of the DSM-IV criteria affects healthcare resource utilization and related costs. Methods: A multicentre, prospective, observational study was conducted in randomly selected outpatient psychiatric clinics between October 2007 and April 2008. Patients diagnosed according to DSM-IV or broader criteria (1 month of excessive or non-excessive worry and only 2 associated DSM-IV symptoms) for the first time were consecutively enrolled. Socio-demographic data, healthcare resources and corresponding costs were collected over a 6-month period. Results: A total of 3549 patients were systematically recruited, 1815 in the DSM-IV criteria group (DG) and1264 inthe broad criteria group (BG). Treatments prescribed were similar for antidepressants in both groups (77.0% in the DG vs. 75.3% in the BG, p = 0.284), and slightly higher in the DG for benzodiazepines (71.5% vs. 67.2% respectively, p = 0.011) and anticonvulsants (72.1% vs. 67.0% respectively, p = 0.002). Healthcare resource utilization was statistically reduced to a similar extent in both groups as a consequence of treatment, yielding a reduction in the cost of illness of €1196 (SD = 1158) and €1112 (SD = 874) respectively;p = 0.304, over a 6-month period. Conclusion: The broadening of the GAD criteria could lead to earlier diagnosis not necessarily associated with an increase in healthcare resource utilization or costs to the National Health System in the six-month follow-up.
基金supported by Natural Science Foundation of Hebei Province(No. F2012203088)
文摘According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is established and a new adaptive robust guaranteed cost controller （AGCC） is proposed in this paper. First, the uncertain parameters of the system are estimated by using the adaptive method, then the estimated uncertain parameters and robust guaranteed cost control method are used to design a state feedback controller. The controller s feedback gain is obtained by solving a set of linear matrix inequality （LMI） constraints, such that the controller can meet a quadratic performance evaluation criterion. The simulation results show that we can realize the goal of maximum wind energy capture in low wind speed by the optimal torque control and constant power control in high wind speed by variable pitch control with good dynamic characteristics, robustness and the ability of suppressing disturbance.
文摘In this present paper, an inventory model with a generalised exponential decreasing demand is considered. A numerical example is used to illustrate the application of the model. Sensitivity analysis of the optimal solution with respect to various parameters is carried out to see the effect of parameter changes on the solution.
基金the National Natural Science Foundation of China ( 1 0 4 71 0 94) ,the ScienceFoundation of Shanghai Technical Sciences Committee ( 0 2 ZA1 40 70 ) and the Science Foundation ofShanghai Education Committee( 0 2 DK0 6)
文摘This paper proposes a nonmonotonic backtracking trust region algorithm via bilevel linear programming for solving the general multicommodity minimal cost flow problems.Using the duality theory of the linear programming and convex theory,the generalized directional derivative of the general multicommodity minimal cost flow problems is derived.The global convergence and superlinear convergence rate of the proposed algorithm are established under some mild conditions.
基金supported by the National Natural Science Foundation of China(61573014)the Fundamental Research Funds for the Central Universities(JB180702).
文摘The maintenance model of simple repairable system is studied.We assume that there are two types of failure,namely type Ⅰ failure(repairable failure)and type Ⅱ failure(irrepairable failure).As long as the type Ⅰ failure occurs,the system will be repaired immediately,which is failure repair(FR).Between the(n-1)th and the nth FR,the system is supposed to be preventively repaired(PR)as the consecutive working time of the system reaches λ^(n-1) T,where λ and T are specified values.Further,we assume that the system will go on working when the repair is finished and will be replaced at the occurrence of the Nth type Ⅰ failure or the occurrence of the first type Ⅱ failure,whichever occurs first.In practice,the system will degrade with the increasing number of repairs.That is,the consecutive working time of the system forms a decreasing generalized geometric process(GGP)whereas the successive repair time forms an increasing GGP.A simple bivariate policy(T,N)repairable model is introduced based on GGP.The alternative searching method is used to minimize the cost rate function C(N,T),and the optimal(T,N)^(*) is obtained.Finally,numerical cases are applied to demonstrate the reasonability of this model.
基金supported by the National Postdoctoral Program for Innovative Talents, Postdoctoral Science Foundation of China (No. 2017M610740)supports from Hefei General Aviation Research Institute, Beihang University
文摘The study of the development cost of general aviation aircraft is limited by small samples with many cost-driven factors. This paper investigates a parametric modeling method for prediction of the development cost of general aviation aircraft. The proposed technique depends on some principal components, acquired by utilizing P value analysis and gray correlation analysis. According to these principal components, the corresponding linear regression and BP neural network models are established respectively. The feasibility and accuracy of the P value analysis are verified by comparing results of model fitting and prediction. A sensitivity analysis related to model precision and suitability is discussed in detail. Results obtained in this study show that the proposed method not only has a certain degree of versatility, but also provides a preliminary prediction of the development cost of general aviation aircraft.
文摘Background: Serum level of cholesterol is one of the most vital risk factors for cardiovascular diseases (CVD). Statins are highly effective drugs for reducing serum cholesterol;hence, preventing coronary heart disease (CHD). Rosuvastatin (Crestor) is one of the most potent and widely prescribed statins. Even though generic statins have been approved based on their bioequivalence with brand-name drugs, there remains considerable concern as regards their effectiveness and safety. Most clinicians and patients welcome the generic drug decreased costs;however, it is indispensable for them that effectiveness and safety are not compromised. Thus, the rationale intended for this study is to compare brand rosuvastatin and generic rosuvastatin as regard their economic impact using a cost-minimization analysis. Methods: This cost-minimization model estimates potential impact of rosuvastatin brand versus generic on the healthcare resource utilization for one-year frame from the payer perspective. The model conforms to real practice of management of hyperlipidemia in Egypt and was validated by experts. Results: The drug costs in the rosuvastatin brand group were 3,155,250 EGP while in the generic group were 2,299,030 EGP. The costs of CVD events in the rosuvastatin brand group were 5,863,558 EGP, while in the generic group were 6,810,180 EGP. The total costs in the rosuvastatin brand group were 9,018,808 EGP, while in the generic group were 9,109,210 EGP with a difference of −100,047 EGP. Conclusions: In conclusion, the real cost of generic treatment is more than that of the brand statin when taking into consideration the cardiovascular events.
