Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source(NPS)pollution.In this paper,the main policies that influence agricultural NPS pollution are c...Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source(NPS)pollution.In this paper,the main policies that influence agricultural NPS pollution are chosen,and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward.According to this,the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.展开更多
China has proposed that it will strive to achieve the carbon neutrality target by 2060,providing strategic guidance for China to accelerate the transformation of its development mode and economic restructuring.But it ...China has proposed that it will strive to achieve the carbon neutrality target by 2060,providing strategic guidance for China to accelerate the transformation of its development mode and economic restructuring.But it is very challenging to achieve the target.It requires systematic top design as well as scientific formulation of long-term planning,while multiple institutional policies and institutional mechanism reforms need to be strengthened,such as rule of law,administration and economy,to form a systematic and effective incentive and constraint mechanism.Through the exploration and improvement of its three five-year plans,China has formed a low-carbon policy guarantee system led by binding targets,highlighting key industries and regions,and comprising planning,laws,administrative orders,pilot projects,markets,finance and taxation,and other aspects.However,there are still many problems,including the lack of clear policy paths in the near,medium and long term,the absence of key systems such as total carbon emission control system and climate legislation,poor inter-departmental communication and coordination mechanisms,and inadequate systems such as carbon markets and climate investment and financing.Finally,taking into account the current opportunities and challenges,we propose a low-carbon development policy guarantee system for China to move towards carbon neutrality.展开更多
From theories and cases,this paper analyzed current situation of subsidy policy system for agricultural natural disasters in China.Improvement and perfection of subsidy policies for agricultural natural disasters need...From theories and cases,this paper analyzed current situation of subsidy policy system for agricultural natural disasters in China.Improvement and perfection of subsidy policies for agricultural natural disasters need clear classification and additional special subsidy plan.It is recommended to improve and perfect subsidy policy system for agricultural natural disasters through attaching importance to scientific studies on reduction and prevention of agricultural disasters and gradually supplementing agricultural disaster reduction and prevention system.展开更多
Objective To analyze the current situation of drug regulation after introducing the new policy for China’s online pharmacy,and to provide reference for the regulation of online pharmacy based on the international exp...Objective To analyze the current situation of drug regulation after introducing the new policy for China’s online pharmacy,and to provide reference for the regulation of online pharmacy based on the international experience.Methods Through literature research and comparative analysis,the history of policies for online pharmacy in China was investigated,and the current situation and problems of regulation for online pharmacy were explored.Results and Conclusion It is found that the body,basis and behavior of online prescription drug supervision in China should be improved.Combining experience in regulating online prescription drug at home and abroad,we provide some suggestions for the implementation of China’s online prescription drug policy by establishing a government-led multiple regulatory mechanism,standardizing the access qualifications for enterprises with business in online prescription drugs,improving the prescription inquiry and review system,and paying attention to consumer needs.展开更多
On May 6,2019,the CPC Central Committee and State Council released the Opinions Concerning Establishing and Improving the Institution,Mechanism,and Policy System for Urban and Rural Integrated Development(shortened in...On May 6,2019,the CPC Central Committee and State Council released the Opinions Concerning Establishing and Improving the Institution,Mechanism,and Policy System for Urban and Rural Integrated Development(shortened into the Opinions in the following part).The Opinions suggests that by 2022,a primary urban-rural integrated development mechanism should be established.An institutional channel for free flowing of urban and rural elements should be basically opened up,the restrictions on urban permanent household registration should be gradually eliminated,the unified urban and rural construction land use market should be set up,the capacity of finance serving for countryside revitalization should be apparently promoted.展开更多
Investigators are attracted by the complexity and significance of preventive maintenance problem,and there are hundreds of maintenance models and methods to solve the maintenance problems of companies and army,going w...Investigators are attracted by the complexity and significance of preventive maintenance problem,and there are hundreds of maintenance models and methods to solve the maintenance problems of companies and army,going with a lot of investigative harvests. However,one-component system or series system is focused by most of the literature.The problem of preventive maintenance（PM） on cold standby repairable system does not attach importance despite the fact that the cold standby repairable system is ubiquitous in engineering systems.In this paper,an optimal replacement model for gamma deteriorating system is studied.This methodology presented uses a gamma distribution to model the material degradation,and the impact of imperfect maintenance actions on system reliability is investigated.After an imperfect maintenance action,the state of a degrading system is assumed as a random variable and the maintenance time follows a geometric process.A maintenance policy（N）is applied by which the system will be repaired whenever it experiences the Nth PM,and an optimal policy（N~＊） could be determined numerically or analytically for minimizing the long-run average cost per unit time.A numerical example about how to confirm the optimal maintenance time by the inspecting information of liquid coupling device is given to demonstrate the use of this policy.This paper presents a condition-based replacement policy for cold standby repairable system under continuous monitoring.Its contribution embody in two aspects,relaxing the restrictions of hypothesis and investigating the condition-based maintenance policy of the cold standby repairable system which is ignored by others.展开更多
This work studies the robust deadlock control of automated manufacturing systems with multiple unreliable resources. Our goal is to ensure the continuous production of the jobs that only require reliable resources. To...This work studies the robust deadlock control of automated manufacturing systems with multiple unreliable resources. Our goal is to ensure the continuous production of the jobs that only require reliable resources. To reach this goal, we propose a new modified Banker's algorithm(MBA) to ensure that all resources required by these jobs can be freed. Moreover,a Petri net based deadlock avoidance policy(DAP) is introduced to ensure that all jobs remaining in the system after executing the new MBA can complete their processing smoothly when their required unreliable resources are operational. The new MBA together with the DAP forms a new DAP that is robust to the failures of unreliable resources. Owing to the high permissiveness of the new MBA and the optimality of the DAP, it is tested to be more permissive than state-of-the-art control policies.展开更多
In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting op...In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.展开更多
The libration control problem of space tether system(STS)for post-capture of payload is studied.The process of payload capture will cause tether swing and deviation from the nominal position,resulting in the failure o...The libration control problem of space tether system(STS)for post-capture of payload is studied.The process of payload capture will cause tether swing and deviation from the nominal position,resulting in the failure of capture mission.Due to unknown inertial parameters after capturing the payload,an adaptive optimal control based on policy iteration is developed to stabilize the uncertain dynamic system in the post-capture phase.By introducing integral reinforcement learning(IRL)scheme,the algebraic Riccati equation(ARE)can be online solved without known dynamics.To avoid computational burden from iteration equations,the online implementation of policy iteration algorithm is provided by the least-squares solution method.Finally,the effectiveness of the algorithm is validated by numerical simulations.展开更多
Background:Despite the well-established health benefits of physical activity(PA)for young people(aged 419 years),most do not meet PA guidelines.Policies that support PA in schools may be promising,but their impact on ...Background:Despite the well-established health benefits of physical activity(PA)for young people(aged 419 years),most do not meet PA guidelines.Policies that support PA in schools may be promising,but their impact on PA behavior is poorly understood.The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.Methods:This systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.Six databases were searched using key concepts of policy,school,evaluation,and PA.Following title and abstract screening of 2323 studies,25 progressed to data synthesis.Methodological quality was assessed using standardized tools,and the strength of the evidence of policy impact was described based on pre-determined codes:positive,negative,inconclusive,or untested statistically.Results:Evidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting.These were whole school PA policy,physical education,sport/extracurricular PA,classroom-based PA,active breaks/recess,physical environment,shared use agreements,active school transport,and surveillance.The bulk of the evidence was significantly positive(54%),27%was inconclusive,9%was significantly negative,and 11%was untested(due to rounding,some numbers add to 99%or 101%).Frequency of evidence was highest in the primary setting(41%),34%in the secondary setting,and 24%in primary/secondary combined school settings.By policy area,frequency of evidence was highest for sport/extracurricular PA(35%),17%for physical education,and 12%for whole school PA policy,with evidence for shared use agreements between schools and local communities rarely reported(2%).Comparing relative strength of evidence,the evidence for shared use agreements,though sparse,was 100%positive,while 60%of the evidence for whole school PA policy,59%of the evidence for sport/extracurricular PA,57%of the evidence for physical education,50%of the evidence for PA in classroom,and 50%of the evidence for active breaks/recess were positive.Conclusion:The current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a“one-sizefits-all”approach and emphasizes the need to examine policy implementation to maximize translation into practice.Greater clarity regarding terminology,measurement,and methods for evaluation of policy interventions is needed.展开更多
As a carrier to develop various marine resources, sea area is regulated as a kind of important resources through legislation by many coastal countries with a management system for the paid use of sea area. Since the e...As a carrier to develop various marine resources, sea area is regulated as a kind of important resources through legislation by many coastal countries with a management system for the paid use of sea area. Since the early 1990s, China has begun to implement the paid use and formed an institutional system comprised of three levels after developing it for more than two decades. From 2002 to 2015, the Chinese Government transferred the use right of sea area of 33,910 km2 by paid use and levied a total of 75.89 billion CNY (11.328 billion US dollars) of sea area use payment. Apart from this, the Government has gained rich experience in operating and managing the compensable use of sea area. After retrospectively analyzing the development history of paid use of China’s sea area, the research presents an institutional structure and the implementation of the management system for the paid use of sea area and the main problems therein. On this basis, management policies and feasible policy suggestions are proposed. Research results from this study can provide available references for other developing countries and emerging economies to apply and improve native management system for the paid use of sea area.展开更多
Aimed at infinite horizon optimal control problems of discrete time-varying nonlinear systems,in this paper,a new iterative adaptive dynamic programming algorithm,which is the discrete-time time-varying policy iterati...Aimed at infinite horizon optimal control problems of discrete time-varying nonlinear systems,in this paper,a new iterative adaptive dynamic programming algorithm,which is the discrete-time time-varying policy iteration(DTTV)algorithm,is developed.The iterative control law is designed to update the iterative value function which approximates the index function of optimal performance.The admissibility of the iterative control law is analyzed.The results show that the iterative value function is non-increasingly convergent to the Bellman-equation optimal solution.To implement the algorithm,neural networks are employed and a new implementation structure is established,which avoids solving the generalized Bellman equation in each iteration.Finally,the optimal control laws for torsional pendulum and inverted pendulum systems are obtained by using the DTTV policy iteration algorithm,where the mass and pendulum bar length are permitted to be time-varying parameters.The effectiveness of the developed method is illustrated by numerical results and comparisons.展开更多
The mobile Intemet industry has exp- erienced dramatic changes as plenty of new applications and business models emerged. This study conducts a qualitative review on the changes through adopting business ecosystem app...The mobile Intemet industry has exp- erienced dramatic changes as plenty of new applications and business models emerged. This study conducts a qualitative review on the changes through adopting business ecosystem approaches. An analytical framework is estab- lished for reviewing the structure of mobile Internet business ecosystem. Then the core value, key actors, and inter-firm relationships of the mobile Internet ecosystem in the past and in the present are compared. It is found that the ecosystem structure has shifted from an MNO-centric model to a polycentric one with highly expanded value sources and di- versified keystone players. Accordingly some suggestions for regulatory policy makers are provided in terms of the roles of mobile Inter- net in social welfare improvement, the call for a convergent regulatory system, and chal- lenges for information security regulation.展开更多
This paper aims to improve the performance of a class of distributed parameter systems for the optimal switching of actuators and controllers based on event-driven control. It is assumed that in the available multiple...This paper aims to improve the performance of a class of distributed parameter systems for the optimal switching of actuators and controllers based on event-driven control. It is assumed that in the available multiple actuators, only one actuator can receive the control signal and be activated over an unfixed time interval, and the other actuators keep dormant. After incorporating a state observer into the event generator, the event-driven control loop and the minimum inter-event time are ultimately bounded. Based on the event-driven state feedback control, the time intervals of unfixed length can be obtained. The optimal switching policy is based on finite horizon linear quadratic optimal control at the beginning of each time subinterval. A simulation example demonstrate the effectiveness of the proposed policy.展开更多
AIM To determine whether recent evidence-based United States polices on male circumcision(MC)apply to comparable Anglophone countries,Australia and New Zealand.METHODS Articles in 2005 through 2015 were retrieved from...AIM To determine whether recent evidence-based United States polices on male circumcision(MC)apply to comparable Anglophone countries,Australia and New Zealand.METHODS Articles in 2005 through 2015 were retrieved from PubM ed using the keyword"circumcision"together with 36 relevant subtopics.A further PubM ed search was performed for articles published in 2016.Searches of the EMBASE and Cochrane databases did not yield additional citable articles.Articles were assessed for quality and those rated 2+and above according to the Scottish Intercollegiate Grading System were studied further.The most relevant andrepresentative of the topic were included.Bibliographies were examined to retrieve further key references.Randomized controlled trials,recent high quality systematic reviews or meta-analyses(level 1++or 1+evidence)were prioritized for inclusion.A risk-benefit analysis of articles rated for quality was performed.For efficiency and reliability,recent randomized controlled trials,metaanalyses,high quality systematic reviews and large welldesigned studies were used if available.Internet searches were conducted for other relevant information,including policies and Australian data on claims under Medicare for MC.RESULTS Evidence-based policy statements by the American Academy of Pediatrics(AAP)and the Centers for Disease Control and Prevention(CDC)support infant and later age male circumcision(MC)as a desirable public health measure.Our systematic review of relevant literature over the past decade yielded 140 journal articles that met our inclusion criteria.Together,these showed that early infant MC confers immediate and lifelong benefits by protecting against urinary tract infections having potential adverse long-term renal effects,phimosis that causes difficult and painful erections and"ballooning"during urination,inflammatory skin conditions,inferior penile hygiene,candidiasis,various sexually transmissible infections in both sexes,genital ulcers,and penile,prostate and cervical cancer.Our risk-benefit analysis showed that benefits exceeded procedural risks,which are predominantly minor,by up to 200 to 1.We estimated that more than 1 in 2 uncircumcised males will experience an adverse foreskin-related medical condition over their lifetime.Wide-ranging evidence from surveys,physiological measurements,and the anatomical location of penile sensory receptors responsible for sexual sensation strongly and consistently suggested that MC has no detrimental effect on sexual function,sensitivity or pleasure.United States studies showed that early infant MC is cost saving.The evidence supporting early infant MC has further strengthened since the positive AAP and CDC reviews.CONCLUSION Affirmative MC policies are needed in Australia and New Zealand.Routine provision of accurate,unbiased education,and access in public hospitals,will maximize health and financial benefits.展开更多
The study empirically assesses how macroprudential policy interacts with systemic risk,industrial production,and monetary intervention on a global level from January 2006 to December 2018.We adopt the aggregate proxie...The study empirically assesses how macroprudential policy interacts with systemic risk,industrial production,and monetary intervention on a global level from January 2006 to December 2018.We adopt the aggregate proxies of these variables,capturing their global effects,and use a novel econometric technique,namely,smooth local projections.The study finds that global macroprudential policy leads the monetary policy,exhibiting a countercyclical pattern concerning industrial production.The latter has an inverse bidirectional linkage with systemic risk.Thus,an ex-ante tight macroprudential policy can indirectly mitigate global systemic risk through its pro-growth effect on industrial production,although no convincing evidence exists for the direct impact of a macroprudential intervention on systemic risk.The study results endure several extensions and a robustness check,which builds on alternative measures of global systemic stress and real economic activity,thereby legitimizing the increased importance attached to the macroprudential policy since the 2007–2009 global financial crisis.展开更多
At present stage,active exploration and healthy development of China’s policy-oriented financial system is hindered by such problems as unclear understanding of policy finance,dislocation of the functions of policy b...At present stage,active exploration and healthy development of China’s policy-oriented financial system is hindered by such problems as unclear understanding of policy finance,dislocation of the functions of policy banks and so on.While sticking to pushing forward the reforms of market-oriented financial system and fully improving the efficiency of the financial system,we must correctly handle the relationship between policy finance and commercial finance,re-examine the position and role of policy finance in the entire financial system of the country,take the policy-oriented financial system as one of the important parts of financing of the social funds,make up and fill in reasonably the"intermediate zone"between the direct fiscal expenditures and commercial financing,pursue the transition of the mechanism relying on government financial resources,realize the multiplexing effect of efficiency promotion,serve the comprehensive,coordinated,sustainable and unified development required by the concept of scientific development and catching-up and breakthrough at some strategic focuses.展开更多
A two-stage method is developed to solve a new class of multi-storage tank multi-source (MTMS) systems. In the first stage, the optimal storage policy of each tank is determined according to the electricity tariff, an...A two-stage method is developed to solve a new class of multi-storage tank multi-source (MTMS) systems. In the first stage, the optimal storage policy of each tank is determined according to the electricity tariff, and the ground-level storage tank is modeled as a node. In the second stage, the genetic algorithm, combined with a repairing scheme, is applied to solve the pump scheduling problem. The objective of the pump scheduling problem is to ensure that the required volume is adequately provided by the pumps while minimizing the operation cost (energy cost and treatment cost). The decision variables are the settings of the pumps and speed ratio of variable-speed pumps at time steps of the total operational time horizon. A mixed coding methodology is developed according to the characteristics of the decision variables. Daily operation cost savings of approximately 11% are obtained by application of the proposed method to a pressure zone of S. Y. water distribution system (WDS), China.展开更多
This paper studies the optimal policy for joint control of admission, routing, service, and jockeying in a queueing system consisting of two exponential servers in parallel.Jobs arrive according to a Poisson process.U...This paper studies the optimal policy for joint control of admission, routing, service, and jockeying in a queueing system consisting of two exponential servers in parallel.Jobs arrive according to a Poisson process.Upon each arrival, an admission/routing decision is made, and the accepted job is routed to one of the two servers with each being associated with a queue.After each service completion, the servers have an option of serving a job from its own queue, serving a jockeying job from another queue, or staying idle.The system performance is inclusive of the revenues from accepted jobs, the costs of holding jobs in queues, the service costs and the job jockeying costs.To maximize the total expected discounted return, we formulate a Markov decision process(MDP) model for this system.The value iteration method is employed to characterize the optimal policy as a hedging point policy.Numerical studies verify the structure of the hedging point policy which is convenient for implementing control actions in practice.展开更多
基金supported by TheResearch Fund for the Doctoral Program of Higher Education(No.20050027014)Program for New Century ExcellentTalents in University(No.NCET-06-0130).
文摘Agricultural and rural economic policy system is one main driving force for the evolvement of agricultural Non-Point Source(NPS)pollution.In this paper,the main policies that influence agricultural NPS pollution are chosen,and a method to evaluate the impacts of agricultural and rural economic policy system on agricultural NPS pollution is brought forward.According to this,the questions about how and to what degree the policy system influence on agricultural NPS pollution are discussed.
文摘China has proposed that it will strive to achieve the carbon neutrality target by 2060,providing strategic guidance for China to accelerate the transformation of its development mode and economic restructuring.But it is very challenging to achieve the target.It requires systematic top design as well as scientific formulation of long-term planning,while multiple institutional policies and institutional mechanism reforms need to be strengthened,such as rule of law,administration and economy,to form a systematic and effective incentive and constraint mechanism.Through the exploration and improvement of its three five-year plans,China has formed a low-carbon policy guarantee system led by binding targets,highlighting key industries and regions,and comprising planning,laws,administrative orders,pilot projects,markets,finance and taxation,and other aspects.However,there are still many problems,including the lack of clear policy paths in the near,medium and long term,the absence of key systems such as total carbon emission control system and climate legislation,poor inter-departmental communication and coordination mechanisms,and inadequate systems such as carbon markets and climate investment and financing.Finally,taking into account the current opportunities and challenges,we propose a low-carbon development policy guarantee system for China to move towards carbon neutrality.
文摘From theories and cases,this paper analyzed current situation of subsidy policy system for agricultural natural disasters in China.Improvement and perfection of subsidy policies for agricultural natural disasters need clear classification and additional special subsidy plan.It is recommended to improve and perfect subsidy policy system for agricultural natural disasters through attaching importance to scientific studies on reduction and prevention of agricultural disasters and gradually supplementing agricultural disaster reduction and prevention system.
文摘Objective To analyze the current situation of drug regulation after introducing the new policy for China’s online pharmacy,and to provide reference for the regulation of online pharmacy based on the international experience.Methods Through literature research and comparative analysis,the history of policies for online pharmacy in China was investigated,and the current situation and problems of regulation for online pharmacy were explored.Results and Conclusion It is found that the body,basis and behavior of online prescription drug supervision in China should be improved.Combining experience in regulating online prescription drug at home and abroad,we provide some suggestions for the implementation of China’s online prescription drug policy by establishing a government-led multiple regulatory mechanism,standardizing the access qualifications for enterprises with business in online prescription drugs,improving the prescription inquiry and review system,and paying attention to consumer needs.
文摘On May 6,2019,the CPC Central Committee and State Council released the Opinions Concerning Establishing and Improving the Institution,Mechanism,and Policy System for Urban and Rural Integrated Development(shortened into the Opinions in the following part).The Opinions suggests that by 2022,a primary urban-rural integrated development mechanism should be established.An institutional channel for free flowing of urban and rural elements should be basically opened up,the restrictions on urban permanent household registration should be gradually eliminated,the unified urban and rural construction land use market should be set up,the capacity of finance serving for countryside revitalization should be apparently promoted.
基金supported by National Natural Science Foundation of China(Grant No.60904002)
文摘Investigators are attracted by the complexity and significance of preventive maintenance problem,and there are hundreds of maintenance models and methods to solve the maintenance problems of companies and army,going with a lot of investigative harvests. However,one-component system or series system is focused by most of the literature.The problem of preventive maintenance（PM） on cold standby repairable system does not attach importance despite the fact that the cold standby repairable system is ubiquitous in engineering systems.In this paper,an optimal replacement model for gamma deteriorating system is studied.This methodology presented uses a gamma distribution to model the material degradation,and the impact of imperfect maintenance actions on system reliability is investigated.After an imperfect maintenance action,the state of a degrading system is assumed as a random variable and the maintenance time follows a geometric process.A maintenance policy（N）is applied by which the system will be repaired whenever it experiences the Nth PM,and an optimal policy（N~＊） could be determined numerically or analytically for minimizing the long-run average cost per unit time.A numerical example about how to confirm the optimal maintenance time by the inspecting information of liquid coupling device is given to demonstrate the use of this policy.This paper presents a condition-based replacement policy for cold standby repairable system under continuous monitoring.Its contribution embody in two aspects,relaxing the restrictions of hypothesis and investigating the condition-based maintenance policy of the cold standby repairable system which is ignored by others.
基金supported in part by the Fundamental Research Funds for the Central Universities(3102017OQD110)the Natural Science Basic Research Plan in Shaanxi Province of China(2019JQ-435)+3 种基金the Project Funded by China Postdoctoral Science Foundation(2019M663818)the National Key Research and Development Program of China(2019YFB1703800)Guangdong Basic and Applied Basic Research Foundation(2019A1515111076)the National Natural Science Foundation of China(71931007)。
文摘This work studies the robust deadlock control of automated manufacturing systems with multiple unreliable resources. Our goal is to ensure the continuous production of the jobs that only require reliable resources. To reach this goal, we propose a new modified Banker's algorithm(MBA) to ensure that all resources required by these jobs can be freed. Moreover,a Petri net based deadlock avoidance policy(DAP) is introduced to ensure that all jobs remaining in the system after executing the new MBA can complete their processing smoothly when their required unreliable resources are operational. The new MBA together with the DAP forms a new DAP that is robust to the failures of unreliable resources. Owing to the high permissiveness of the new MBA and the optimality of the DAP, it is tested to be more permissive than state-of-the-art control policies.
基金supported by the National Natural Science Foundation of China(7170120971771216)+1 种基金Shaanxi Natural Science Foundation(2019JQ-250)China Post-doctoral Fund(2019M653962)
文摘In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.
基金supported by the National Natural Science Foundation of China(No.62111530051)the Fundamental Research Funds for the Central Universities(No.3102017JC06002)the Shaanxi Science and Technology Program,China(No.2017KW-ZD-04).
文摘The libration control problem of space tether system(STS)for post-capture of payload is studied.The process of payload capture will cause tether swing and deviation from the nominal position,resulting in the failure of capture mission.Due to unknown inertial parameters after capturing the payload,an adaptive optimal control based on policy iteration is developed to stabilize the uncertain dynamic system in the post-capture phase.By introducing integral reinforcement learning(IRL)scheme,the algebraic Riccati equation(ARE)can be online solved without known dynamics.To avoid computational burden from iteration equations,the online implementation of policy iteration algorithm is provided by the least-squares solution method.Finally,the effectiveness of the algorithm is validated by numerical simulations.
文摘Background:Despite the well-established health benefits of physical activity(PA)for young people(aged 419 years),most do not meet PA guidelines.Policies that support PA in schools may be promising,but their impact on PA behavior is poorly understood.The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.Methods:This systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.Six databases were searched using key concepts of policy,school,evaluation,and PA.Following title and abstract screening of 2323 studies,25 progressed to data synthesis.Methodological quality was assessed using standardized tools,and the strength of the evidence of policy impact was described based on pre-determined codes:positive,negative,inconclusive,or untested statistically.Results:Evidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting.These were whole school PA policy,physical education,sport/extracurricular PA,classroom-based PA,active breaks/recess,physical environment,shared use agreements,active school transport,and surveillance.The bulk of the evidence was significantly positive(54%),27%was inconclusive,9%was significantly negative,and 11%was untested(due to rounding,some numbers add to 99%or 101%).Frequency of evidence was highest in the primary setting(41%),34%in the secondary setting,and 24%in primary/secondary combined school settings.By policy area,frequency of evidence was highest for sport/extracurricular PA(35%),17%for physical education,and 12%for whole school PA policy,with evidence for shared use agreements between schools and local communities rarely reported(2%).Comparing relative strength of evidence,the evidence for shared use agreements,though sparse,was 100%positive,while 60%of the evidence for whole school PA policy,59%of the evidence for sport/extracurricular PA,57%of the evidence for physical education,50%of the evidence for PA in classroom,and 50%of the evidence for active breaks/recess were positive.Conclusion:The current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a“one-sizefits-all”approach and emphasizes the need to examine policy implementation to maximize translation into practice.Greater clarity regarding terminology,measurement,and methods for evaluation of policy interventions is needed.
文摘As a carrier to develop various marine resources, sea area is regulated as a kind of important resources through legislation by many coastal countries with a management system for the paid use of sea area. Since the early 1990s, China has begun to implement the paid use and formed an institutional system comprised of three levels after developing it for more than two decades. From 2002 to 2015, the Chinese Government transferred the use right of sea area of 33,910 km2 by paid use and levied a total of 75.89 billion CNY (11.328 billion US dollars) of sea area use payment. Apart from this, the Government has gained rich experience in operating and managing the compensable use of sea area. After retrospectively analyzing the development history of paid use of China’s sea area, the research presents an institutional structure and the implementation of the management system for the paid use of sea area and the main problems therein. On this basis, management policies and feasible policy suggestions are proposed. Research results from this study can provide available references for other developing countries and emerging economies to apply and improve native management system for the paid use of sea area.
基金supported in part by Fundamental Research Funds for the Central Universities(2022JBZX024)in part by the National Natural Science Foundation of China(61872037,61273167)。
文摘Aimed at infinite horizon optimal control problems of discrete time-varying nonlinear systems,in this paper,a new iterative adaptive dynamic programming algorithm,which is the discrete-time time-varying policy iteration(DTTV)algorithm,is developed.The iterative control law is designed to update the iterative value function which approximates the index function of optimal performance.The admissibility of the iterative control law is analyzed.The results show that the iterative value function is non-increasingly convergent to the Bellman-equation optimal solution.To implement the algorithm,neural networks are employed and a new implementation structure is established,which avoids solving the generalized Bellman equation in each iteration.Finally,the optimal control laws for torsional pendulum and inverted pendulum systems are obtained by using the DTTV policy iteration algorithm,where the mass and pendulum bar length are permitted to be time-varying parameters.The effectiveness of the developed method is illustrated by numerical results and comparisons.
基金supported by the China Fundamental Research Funds for the Central Universities under Grant No.BUPT2012RC1011
文摘The mobile Intemet industry has exp- erienced dramatic changes as plenty of new applications and business models emerged. This study conducts a qualitative review on the changes through adopting business ecosystem approaches. An analytical framework is estab- lished for reviewing the structure of mobile Internet business ecosystem. Then the core value, key actors, and inter-firm relationships of the mobile Internet ecosystem in the past and in the present are compared. It is found that the ecosystem structure has shifted from an MNO-centric model to a polycentric one with highly expanded value sources and di- versified keystone players. Accordingly some suggestions for regulatory policy makers are provided in terms of the roles of mobile Inter- net in social welfare improvement, the call for a convergent regulatory system, and chal- lenges for information security regulation.
基金supported by the National Natural Science Foundation of China(Grant Nos.61174021 and 61104155)the Fundamental Research Funds for theCentral Universities,China(Grant Nos.JUDCF13037 and JUSRP51322B)+1 种基金the Programme of Introducing Talents of Discipline to Universities,China(GrantNo.B12018)the Jiangsu Innovation Program for Graduates,China(Grant No.CXZZ13-0740)
文摘This paper aims to improve the performance of a class of distributed parameter systems for the optimal switching of actuators and controllers based on event-driven control. It is assumed that in the available multiple actuators, only one actuator can receive the control signal and be activated over an unfixed time interval, and the other actuators keep dormant. After incorporating a state observer into the event generator, the event-driven control loop and the minimum inter-event time are ultimately bounded. Based on the event-driven state feedback control, the time intervals of unfixed length can be obtained. The optimal switching policy is based on finite horizon linear quadratic optimal control at the beginning of each time subinterval. A simulation example demonstrate the effectiveness of the proposed policy.
文摘AIM To determine whether recent evidence-based United States polices on male circumcision(MC)apply to comparable Anglophone countries,Australia and New Zealand.METHODS Articles in 2005 through 2015 were retrieved from PubM ed using the keyword"circumcision"together with 36 relevant subtopics.A further PubM ed search was performed for articles published in 2016.Searches of the EMBASE and Cochrane databases did not yield additional citable articles.Articles were assessed for quality and those rated 2+and above according to the Scottish Intercollegiate Grading System were studied further.The most relevant andrepresentative of the topic were included.Bibliographies were examined to retrieve further key references.Randomized controlled trials,recent high quality systematic reviews or meta-analyses(level 1++or 1+evidence)were prioritized for inclusion.A risk-benefit analysis of articles rated for quality was performed.For efficiency and reliability,recent randomized controlled trials,metaanalyses,high quality systematic reviews and large welldesigned studies were used if available.Internet searches were conducted for other relevant information,including policies and Australian data on claims under Medicare for MC.RESULTS Evidence-based policy statements by the American Academy of Pediatrics(AAP)and the Centers for Disease Control and Prevention(CDC)support infant and later age male circumcision(MC)as a desirable public health measure.Our systematic review of relevant literature over the past decade yielded 140 journal articles that met our inclusion criteria.Together,these showed that early infant MC confers immediate and lifelong benefits by protecting against urinary tract infections having potential adverse long-term renal effects,phimosis that causes difficult and painful erections and"ballooning"during urination,inflammatory skin conditions,inferior penile hygiene,candidiasis,various sexually transmissible infections in both sexes,genital ulcers,and penile,prostate and cervical cancer.Our risk-benefit analysis showed that benefits exceeded procedural risks,which are predominantly minor,by up to 200 to 1.We estimated that more than 1 in 2 uncircumcised males will experience an adverse foreskin-related medical condition over their lifetime.Wide-ranging evidence from surveys,physiological measurements,and the anatomical location of penile sensory receptors responsible for sexual sensation strongly and consistently suggested that MC has no detrimental effect on sexual function,sensitivity or pleasure.United States studies showed that early infant MC is cost saving.The evidence supporting early infant MC has further strengthened since the positive AAP and CDC reviews.CONCLUSION Affirmative MC policies are needed in Australia and New Zealand.Routine provision of accurate,unbiased education,and access in public hospitals,will maximize health and financial benefits.
文摘The study empirically assesses how macroprudential policy interacts with systemic risk,industrial production,and monetary intervention on a global level from January 2006 to December 2018.We adopt the aggregate proxies of these variables,capturing their global effects,and use a novel econometric technique,namely,smooth local projections.The study finds that global macroprudential policy leads the monetary policy,exhibiting a countercyclical pattern concerning industrial production.The latter has an inverse bidirectional linkage with systemic risk.Thus,an ex-ante tight macroprudential policy can indirectly mitigate global systemic risk through its pro-growth effect on industrial production,although no convincing evidence exists for the direct impact of a macroprudential intervention on systemic risk.The study results endure several extensions and a robustness check,which builds on alternative measures of global systemic stress and real economic activity,thereby legitimizing the increased importance attached to the macroprudential policy since the 2007–2009 global financial crisis.
文摘At present stage,active exploration and healthy development of China’s policy-oriented financial system is hindered by such problems as unclear understanding of policy finance,dislocation of the functions of policy banks and so on.While sticking to pushing forward the reforms of market-oriented financial system and fully improving the efficiency of the financial system,we must correctly handle the relationship between policy finance and commercial finance,re-examine the position and role of policy finance in the entire financial system of the country,take the policy-oriented financial system as one of the important parts of financing of the social funds,make up and fill in reasonably the"intermediate zone"between the direct fiscal expenditures and commercial financing,pursue the transition of the mechanism relying on government financial resources,realize the multiplexing effect of efficiency promotion,serve the comprehensive,coordinated,sustainable and unified development required by the concept of scientific development and catching-up and breakthrough at some strategic focuses.
基金Project supported by the National Science & Technology Pillar Program during the Eleventh Five-year Plan Period (No. 2006BAJ08B03), China
文摘A two-stage method is developed to solve a new class of multi-storage tank multi-source (MTMS) systems. In the first stage, the optimal storage policy of each tank is determined according to the electricity tariff, and the ground-level storage tank is modeled as a node. In the second stage, the genetic algorithm, combined with a repairing scheme, is applied to solve the pump scheduling problem. The objective of the pump scheduling problem is to ensure that the required volume is adequately provided by the pumps while minimizing the operation cost (energy cost and treatment cost). The decision variables are the settings of the pumps and speed ratio of variable-speed pumps at time steps of the total operational time horizon. A mixed coding methodology is developed according to the characteristics of the decision variables. Daily operation cost savings of approximately 11% are obtained by application of the proposed method to a pressure zone of S. Y. water distribution system (WDS), China.
基金supported by the National Social Science Fund of China (19BGL100)。
文摘This paper studies the optimal policy for joint control of admission, routing, service, and jockeying in a queueing system consisting of two exponential servers in parallel.Jobs arrive according to a Poisson process.Upon each arrival, an admission/routing decision is made, and the accepted job is routed to one of the two servers with each being associated with a queue.After each service completion, the servers have an option of serving a job from its own queue, serving a jockeying job from another queue, or staying idle.The system performance is inclusive of the revenues from accepted jobs, the costs of holding jobs in queues, the service costs and the job jockeying costs.To maximize the total expected discounted return, we formulate a Markov decision process(MDP) model for this system.The value iteration method is employed to characterize the optimal policy as a hedging point policy.Numerical studies verify the structure of the hedging point policy which is convenient for implementing control actions in practice.
