By studying the behavioral psychology and needs of children,this paper analyzes the essence of child-friendly parks from the perspective of children,and discusses the design principles and key points of child-friendly...By studying the behavioral psychology and needs of children,this paper analyzes the essence of child-friendly parks from the perspective of children,and discusses the design principles and key points of child-friendly parks,so as to provide a practical basis for the construction of child-friendly cities.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
At present,in the world the development of space is undergoing profound changes brought by commercial space,from the traditional government-driven development to the joint government and market promotion.This paper an...At present,in the world the development of space is undergoing profound changes brought by commercial space,from the traditional government-driven development to the joint government and market promotion.This paper analyzes the current status of both foreign and domestic commercial space markets and policies,and then put forward the ideas and inspirations for the development of China’s commercial space market.展开更多
India,despite being a leading space-faring nation,and operating one of the six largest space programmes in the world,has developed little in terms of expressly documented national space policy over its 58-year history...India,despite being a leading space-faring nation,and operating one of the six largest space programmes in the world,has developed little in terms of expressly documented national space policy over its 58-year history of space activity-besides two standalone policy documents primarily designed to address some operational policy issues pertaining to satellite communication services and use of remote sensing data.However,the Indian space programme,given its phenomenal technological advancements and operational maturity achieved over the decades,clearly exhibits evidence of having been continually and consistently guided,since its very inception,by a cohesive and consistent policy so far as its directional and strategic policy aspects are concerned.In other words,there does exist an apparent undeclared policy embedded in the Indian space establishment that has continued to inform and guide its strategic decisions and actions.The objective of the present case-study is to systematically describe the evolution of the national space policy of India,predominantly as implicit policy,as reflected by the key decisions and actions of the Indian national space establishment since beginning of the Indian space programme.This analysis strives to identify the directional and the strategic elements of policy as reflected by the decisions and actions of the space establishment,and the socio-economic,technological,political and institutional factors that have influenced such policies.展开更多
文摘By studying the behavioral psychology and needs of children,this paper analyzes the essence of child-friendly parks from the perspective of children,and discusses the design principles and key points of child-friendly parks,so as to provide a practical basis for the construction of child-friendly cities.
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At present,in the world the development of space is undergoing profound changes brought by commercial space,from the traditional government-driven development to the joint government and market promotion.This paper analyzes the current status of both foreign and domestic commercial space markets and policies,and then put forward the ideas and inspirations for the development of China’s commercial space market.
文摘India,despite being a leading space-faring nation,and operating one of the six largest space programmes in the world,has developed little in terms of expressly documented national space policy over its 58-year history of space activity-besides two standalone policy documents primarily designed to address some operational policy issues pertaining to satellite communication services and use of remote sensing data.However,the Indian space programme,given its phenomenal technological advancements and operational maturity achieved over the decades,clearly exhibits evidence of having been continually and consistently guided,since its very inception,by a cohesive and consistent policy so far as its directional and strategic policy aspects are concerned.In other words,there does exist an apparent undeclared policy embedded in the Indian space establishment that has continued to inform and guide its strategic decisions and actions.The objective of the present case-study is to systematically describe the evolution of the national space policy of India,predominantly as implicit policy,as reflected by the key decisions and actions of the Indian national space establishment since beginning of the Indian space programme.This analysis strives to identify the directional and the strategic elements of policy as reflected by the decisions and actions of the space establishment,and the socio-economic,technological,political and institutional factors that have influenced such policies.
