Based on the current studies,a reasonable evaluation index system was established by the development coordination of analysis systems.Furthermore,taking grassland resources in Nagchu Tibet as an example and according ...Based on the current studies,a reasonable evaluation index system was established by the development coordination of analysis systems.Furthermore,taking grassland resources in Nagchu Tibet as an example and according to the coordination degree evaluation model of the environmental economy system,a coordination degree evaluation index system of environmental economy was set up,and the coordination conditions of 11 counties in Nagchu district were analyzed by coordination function.展开更多
For the rapidly developing unmanned aerial vehicle(UAV)swarm,the system-of-systems(SoS)oriented design is a prospective conceptual design methodology due to the competence for complex mission requirements and subsyste...For the rapidly developing unmanned aerial vehicle(UAV)swarm,the system-of-systems(SoS)oriented design is a prospective conceptual design methodology due to the competence for complex mission requirements and subsystems interactions.In the SoS oriented design,the subsystems performance trade-off is the basis of design decisions.In the trade-off for surveillance missions,most previous works do not consider track reporting and mainly focus on the design of platforms.An improved method for the subsystems performance trade-off in the SoS oriented UAV swarm design is proposed.Within an improved design framework with subsystems disaggregation,this method is characterized by treating platforms,sensors,and communications as equally important subsystems,integrating operational strategies into the trade-off,and enabling the trade-off for track reporting.Those advantages are achieved by a behavior-based modular model structure for agent-based operational modeling and simulation.In addition,a method of analyzing the bounds of the communication range is also presented.Simulation experiments are conducted by using precision-based simulation replication rules and surrogate modeling methods.The results demonstrate the effectiveness of the proposed method,and show that the configuration of area partitioning changes the trade space of subsystems performances,indicating the necessity of integrating operational strategies into the conceptual design.展开更多
The intense application of Voltage Source Converter based HVDC interconnections and grids will result in a hybrid AC-HVDC-system. The operation of such a system becomes complex regarding system security and system ope...The intense application of Voltage Source Converter based HVDC interconnections and grids will result in a hybrid AC-HVDC-system. The operation of such a system becomes complex regarding system security and system operation. This paper describes major challenges and proposes potential solutions, including a combined security assessment, preventive optimization and curative actions. A coordination of both systems enables an efficient application of existing transport capacity.展开更多
Nonalcoholic fatty liver disease(NAFLD) is the most common cause of chronic liver disease. NAFLD includes a wide spectrum of liver conditions ranging from simple steatosis to nonalcoholic steatohepatitis and advanced ...Nonalcoholic fatty liver disease(NAFLD) is the most common cause of chronic liver disease. NAFLD includes a wide spectrum of liver conditions ranging from simple steatosis to nonalcoholic steatohepatitis and advanced hepatic fibrosis. NAFLD has been recognized as a hepatic manifestation of metabolic syndrome linked with insulin resistance. NAFLD should be considered not only a liver specific disease but also an early mediator of systemic diseases. Therefore, NAFLD is usually associated with cardiovascular disease, chronic kidney disease, type 2 diabetes, obesity, and dyslipidemia. NAFLD is highly prevalent in the general population and is associated with increased cardiovascular morbidity and mortality. The underlying mechanisms and pathogenesis of NAFLD with regard to other medical disorders are not yet fully understood. This review focuses on pathogenesis of NAFLD and its relation with other systemic diseases.展开更多
To makesystem-of-systems combat simulation models easy to be developed and reused, simulation model formal specification and representation are researched. According to the view of system-of-systems combat simulation,...To makesystem-of-systems combat simulation models easy to be developed and reused, simulation model formal specification and representation are researched. According to the view of system-of-systems combat simulation, and based on DEVS, the simulation model＇s fundamental formalisms are explored. It includes entity model, system-of-systems model and experiment model. It also presents rigorous formal specification. XML data exchange standard is combined to design the XML based language, SCSL, to support simulation model representation. The corresponding relationship between SCSL and simulation model formalism is discussed and the syntax and semantics of elements in SCSL are detailed. Based on simulation model formal specification, the abstract simulation algorithm is given and SCSL virtual machine, which is capable of automatically interpreting and executing simulation model represented by SCSL, is designed. Finally an application case is presented, which can show the validation of the theory and verification of SCSL.展开更多
Partial linearization method is proposed for controlling Lü-system.Through partially cancelling the nonlinear cross-coupling terms the stabilization of the resulting system was realized.This method can be easily ...Partial linearization method is proposed for controlling Lü-system.Through partially cancelling the nonlinear cross-coupling terms the stabilization of the resulting system was realized.This method can be easily realized.The robust behavior was proved with respect to an uncertain system.Numerical simulation are provided to show the effectiveness and feasibility of the method.展开更多
AIM:To present a dedicated series of transjugular intrahepatic porto-systemic shunts(TIPS) in the elderly since data is sparse on this population group.METHODS:A retrospective review was performed of patients at least...AIM:To present a dedicated series of transjugular intrahepatic porto-systemic shunts(TIPS) in the elderly since data is sparse on this population group.METHODS:A retrospective review was performed of patients at least 65 years of age who underwent TIPS at our institutions between 1997 and 2010.Twentyfive patients were referred for TIPS.We deemed that 2 patients were not considered appropriate candidates due to their markedly advanced liver disease.Of the 23 patients suitable for TIPS,the indications for TIPS placement was portal hypertension complicated by refractory ascites alone(n = 9),hepatic hydrothorax alone(n = 2),refractory ascites and hydrothorax(n = 1),gastrointestinal bleeding alone(n = 8),gastrointestinal bleeding and ascites(n = 3).RESULTS:Of these 23 attempted TIPS procedure patients,21 patients had technically successful TIPS procedures.A total of 29 out of 32 TIPS procedures including revisions were successful in 21 patients with a mean age of 72.1 years(range 65-82 years).Three of the procedures were unsuccessful attempts at TIPS and 8 procedures were successful revisions of our existing TIPS.Sixteen of 21 patients who underwent successful TIPS(excluding 5 patients lost to follow-up) were followed for a mean of 14.7 mo.Ascites and/or hydrothorax was controlled following technically successful procedures in 12 of 13 patients.Bleeding was controlled following technically successful procedures in 10 out of 11 patients.CONCLUSION:We have demonstrated that TIPS is an effective procedure to control refractory complications of portal hypertension in elderly patients.展开更多
An initial-boundary values problem in the half space （0, ∞ ） for p-system with artificial viscosity is investigated. It is shown that there exists a boundary layer solution. It is further proved that the boundary l...An initial-boundary values problem in the half space （0, ∞ ） for p-system with artificial viscosity is investigated. It is shown that there exists a boundary layer solution. It is further proved that the boundary layer solution is nonlinear stable with arbitrarily large perturbation. The proof is given by an elementary energy method.展开更多
基金Supported by National Soft Science Program (2006GXS2B029)
文摘Based on the current studies,a reasonable evaluation index system was established by the development coordination of analysis systems.Furthermore,taking grassland resources in Nagchu Tibet as an example and according to the coordination degree evaluation model of the environmental economy system,a coordination degree evaluation index system of environmental economy was set up,and the coordination conditions of 11 counties in Nagchu district were analyzed by coordination function.
基金supported by the National Natural Science Foundation of China(11872314)the National Key Research and Development Program of China(2017YFB1300102)
文摘For the rapidly developing unmanned aerial vehicle(UAV)swarm,the system-of-systems(SoS)oriented design is a prospective conceptual design methodology due to the competence for complex mission requirements and subsystems interactions.In the SoS oriented design,the subsystems performance trade-off is the basis of design decisions.In the trade-off for surveillance missions,most previous works do not consider track reporting and mainly focus on the design of platforms.An improved method for the subsystems performance trade-off in the SoS oriented UAV swarm design is proposed.Within an improved design framework with subsystems disaggregation,this method is characterized by treating platforms,sensors,and communications as equally important subsystems,integrating operational strategies into the trade-off,and enabling the trade-off for track reporting.Those advantages are achieved by a behavior-based modular model structure for agent-based operational modeling and simulation.In addition,a method of analyzing the bounds of the communication range is also presented.Simulation experiments are conducted by using precision-based simulation replication rules and surrogate modeling methods.The results demonstrate the effectiveness of the proposed method,and show that the configuration of area partitioning changes the trade space of subsystems performances,indicating the necessity of integrating operational strategies into the conceptual design.
文摘The intense application of Voltage Source Converter based HVDC interconnections and grids will result in a hybrid AC-HVDC-system. The operation of such a system becomes complex regarding system security and system operation. This paper describes major challenges and proposes potential solutions, including a combined security assessment, preventive optimization and curative actions. A coordination of both systems enables an efficient application of existing transport capacity.
文摘Nonalcoholic fatty liver disease(NAFLD) is the most common cause of chronic liver disease. NAFLD includes a wide spectrum of liver conditions ranging from simple steatosis to nonalcoholic steatohepatitis and advanced hepatic fibrosis. NAFLD has been recognized as a hepatic manifestation of metabolic syndrome linked with insulin resistance. NAFLD should be considered not only a liver specific disease but also an early mediator of systemic diseases. Therefore, NAFLD is usually associated with cardiovascular disease, chronic kidney disease, type 2 diabetes, obesity, and dyslipidemia. NAFLD is highly prevalent in the general population and is associated with increased cardiovascular morbidity and mortality. The underlying mechanisms and pathogenesis of NAFLD with regard to other medical disorders are not yet fully understood. This review focuses on pathogenesis of NAFLD and its relation with other systemic diseases.
文摘To makesystem-of-systems combat simulation models easy to be developed and reused, simulation model formal specification and representation are researched. According to the view of system-of-systems combat simulation, and based on DEVS, the simulation model＇s fundamental formalisms are explored. It includes entity model, system-of-systems model and experiment model. It also presents rigorous formal specification. XML data exchange standard is combined to design the XML based language, SCSL, to support simulation model representation. The corresponding relationship between SCSL and simulation model formalism is discussed and the syntax and semantics of elements in SCSL are detailed. Based on simulation model formal specification, the abstract simulation algorithm is given and SCSL virtual machine, which is capable of automatically interpreting and executing simulation model represented by SCSL, is designed. Finally an application case is presented, which can show the validation of the theory and verification of SCSL.
文摘Partial linearization method is proposed for controlling Lü-system.Through partially cancelling the nonlinear cross-coupling terms the stabilization of the resulting system was realized.This method can be easily realized.The robust behavior was proved with respect to an uncertain system.Numerical simulation are provided to show the effectiveness and feasibility of the method.
文摘AIM:To present a dedicated series of transjugular intrahepatic porto-systemic shunts(TIPS) in the elderly since data is sparse on this population group.METHODS:A retrospective review was performed of patients at least 65 years of age who underwent TIPS at our institutions between 1997 and 2010.Twentyfive patients were referred for TIPS.We deemed that 2 patients were not considered appropriate candidates due to their markedly advanced liver disease.Of the 23 patients suitable for TIPS,the indications for TIPS placement was portal hypertension complicated by refractory ascites alone(n = 9),hepatic hydrothorax alone(n = 2),refractory ascites and hydrothorax(n = 1),gastrointestinal bleeding alone(n = 8),gastrointestinal bleeding and ascites(n = 3).RESULTS:Of these 23 attempted TIPS procedure patients,21 patients had technically successful TIPS procedures.A total of 29 out of 32 TIPS procedures including revisions were successful in 21 patients with a mean age of 72.1 years(range 65-82 years).Three of the procedures were unsuccessful attempts at TIPS and 8 procedures were successful revisions of our existing TIPS.Sixteen of 21 patients who underwent successful TIPS(excluding 5 patients lost to follow-up) were followed for a mean of 14.7 mo.Ascites and/or hydrothorax was controlled following technically successful procedures in 12 of 13 patients.Bleeding was controlled following technically successful procedures in 10 out of 11 patients.CONCLUSION:We have demonstrated that TIPS is an effective procedure to control refractory complications of portal hypertension in elderly patients.
基金Partially supported by NSFC-NSAF (10676037) and NUST
文摘An initial-boundary values problem in the half space （0, ∞ ） for p-system with artificial viscosity is investigated. It is shown that there exists a boundary layer solution. It is further proved that the boundary layer solution is nonlinear stable with arbitrarily large perturbation. The proof is given by an elementary energy method.
