In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use th...In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use the idea of changing variables to transform the model into a uniform dispersal one.Then the existence and uniqueness of positive stationary solution to the model can be verified by the squeezing argument,where the solution plays a crucial role in later analyses.Moreover,the asymptotic behavior of solutions to the model is obtained by the upper-lower solutions method.The result indicates that the solutions of the model converge to the corresponding positive stationary solution locally uniformly in one dimension as time goes to infinity.展开更多
After 1995, Tibet entered the stage of accelerated urbanization. The large floating population fi＇om outside Tibet has become the driving force for urban expansion and the rising of urbanization rate. After analyzing...After 1995, Tibet entered the stage of accelerated urbanization. The large floating population fi＇om outside Tibet has become the driving force for urban expansion and the rising of urbanization rate. After analyzing the changes of urban functions and spatial structure of urban system in Tibet, this paper argues that before 1995 the urbanization in Tibet was mainly driven by administrative function, resulting in certain population migration, whereas in the past decade economic function has become the key factor accelerating urban expansion with the market mechanism creating large-scale inflow of population. The floating population-based urbanization and high population growth in the agricultural and pastoral areas of Tibet has promoted the regional economic prosperity, but exerted resources and environmental pressure and brought some problems for Tibetan culture protection at the same time. The conflicts and contradictions between urbanization and the sustainability of natural resources, environment and social development have been intensified. Addressing these problems, this paper proposes some countermeasures for improving the sustainability of Tibetan urbanization.展开更多
Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regener...Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model including considered silvicultural effort, tax subsidies, risk dynamic management, and forest regeneration factors are made in more detailed explanations. This article concludes with the future further research directions of forest economics, including the design of dynamic models that includes considered uneven-aged forest management, non-timber goods and services, dynamic forest models. The research reflects the general trend of interdisciplinary and cross-border.展开更多
Cloud computing is a new vision about the needs of information technology （IT）. It provides a comprehensive concept for building a homogeneous environment through services offered in the cloud Software-as-a-Service ...Cloud computing is a new vision about the needs of information technology （IT）. It provides a comprehensive concept for building a homogeneous environment through services offered in the cloud Software-as-a-Service （SaaS）, Platform-as-a-Service （PaaS）, and Infrastructure-as-a-Service （IaaS）. Cloud computing is location-independent computing, whereby shared servers provide resources, software, and data to computers and other devices on demand, as with the electricity grid. Cloud computing is computing paradigm that is driven by economies of scale, in which a set of dynamically-scalable resources such as servers, storages, platforms, and services are delivered on demand to the customers over the interuet. ＂Cloud computing is a continuation of the direction the industry has been going for the last several years in terms of using shared and elastically scalable computing resources,＂ says Rex Wang1, VP of Product Marketing at Oracle, who spoke at the Gartner Data Center Conference, in January 2011. Cloud computing refers to dynamic provision of virtual distributed computational resources on demand via a computer network. Cloud computing is a new high technology industry that possesses a number of advantages over existing business practices： a reduction of expenses, technical staff, and efforts of the end users.展开更多
In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P stre...In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P streaming system,a peer priority based scheduling algorithm is proposed.The algorithm calculates neighbors' priority based on peers' historical service evaluation as well as how many wanted data that the neighbor has.The data request allocated to each neighbor is adjusted dynamically according to the priority when scheduling.Peers with high priority are preferred to allocate more data request.Experiment shows the algorithm can make full use of neighbors' bandwidth resources to transmit data to reduce server pressure effectively and improve system scalability.展开更多
The economic regionalization practice led by China local governments has gradually evolved into chaos. Local governments compete to declare for higher-leveled and large-scaled economic regions to obtain more economic ...The economic regionalization practice led by China local governments has gradually evolved into chaos. Local governments compete to declare for higher-leveled and large-scaled economic regions to obtain more economic resources and policy support in the way of policy game. The author argues that the regionalization chaos is attributed to the reason that the present theoretical support for economic regionalization overemphasizes the economic growth brought about by the economic regionalization but ignores the effect of transaction cost, which leads to constraint loss on the economic regionalization theory analysis framework. Then, the introduction of economic regionalization analysis framework based on the conflicts between scale expansion and transaction costs would establish equilibrium conditions to set up a moderate scale development for economic regions. The author hopes that the acceptance of this framework into the economic regionalization decision-making system would give guidance for making more appropriate regionalization decisions.展开更多
基金supported by the National Natural Science Foundation of China (Nos.12301101,12101121)the Guangdong Basic and Applied Basic Research Foundation (Nos.2022A1515110019,2020A1515110585)。
文摘In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use the idea of changing variables to transform the model into a uniform dispersal one.Then the existence and uniqueness of positive stationary solution to the model can be verified by the squeezing argument,where the solution plays a crucial role in later analyses.Moreover,the asymptotic behavior of solutions to the model is obtained by the upper-lower solutions method.The result indicates that the solutions of the model converge to the corresponding positive stationary solution locally uniformly in one dimension as time goes to infinity.
基金Under the auspices of Key Program of National Natural Science Foundation of China (No. 40830741)
文摘After 1995, Tibet entered the stage of accelerated urbanization. The large floating population fi＇om outside Tibet has become the driving force for urban expansion and the rising of urbanization rate. After analyzing the changes of urban functions and spatial structure of urban system in Tibet, this paper argues that before 1995 the urbanization in Tibet was mainly driven by administrative function, resulting in certain population migration, whereas in the past decade economic function has become the key factor accelerating urban expansion with the market mechanism creating large-scale inflow of population. The floating population-based urbanization and high population growth in the agricultural and pastoral areas of Tibet has promoted the regional economic prosperity, but exerted resources and environmental pressure and brought some problems for Tibetan culture protection at the same time. The conflicts and contradictions between urbanization and the sustainability of natural resources, environment and social development have been intensified. Addressing these problems, this paper proposes some countermeasures for improving the sustainability of Tibetan urbanization.
基金funded by the Humanities and So-cial Sciences Youth Fund Program under Ministry of Education and the program name is "The research about risk avoidance behavior in the production process of Chinese farmers" (Grant no.09YJC790214)
文摘Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model including considered silvicultural effort, tax subsidies, risk dynamic management, and forest regeneration factors are made in more detailed explanations. This article concludes with the future further research directions of forest economics, including the design of dynamic models that includes considered uneven-aged forest management, non-timber goods and services, dynamic forest models. The research reflects the general trend of interdisciplinary and cross-border.
文摘Cloud computing is a new vision about the needs of information technology （IT）. It provides a comprehensive concept for building a homogeneous environment through services offered in the cloud Software-as-a-Service （SaaS）, Platform-as-a-Service （PaaS）, and Infrastructure-as-a-Service （IaaS）. Cloud computing is location-independent computing, whereby shared servers provide resources, software, and data to computers and other devices on demand, as with the electricity grid. Cloud computing is computing paradigm that is driven by economies of scale, in which a set of dynamically-scalable resources such as servers, storages, platforms, and services are delivered on demand to the customers over the interuet. ＂Cloud computing is a continuation of the direction the industry has been going for the last several years in terms of using shared and elastically scalable computing resources,＂ says Rex Wang1, VP of Product Marketing at Oracle, who spoke at the Gartner Data Center Conference, in January 2011. Cloud computing refers to dynamic provision of virtual distributed computational resources on demand via a computer network. Cloud computing is a new high technology industry that possesses a number of advantages over existing business practices： a reduction of expenses, technical staff, and efforts of the end users.
基金Supported by the National High Technology Research and Development Program of China(No.2009AA01A339,2008AA01A317)the National Natural Science Foundation of China for Distinguished Young Scholars(No.60903218F0208)the Science and Technology Support Plan of China(No.2008BAH28B04)
文摘In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P streaming system,a peer priority based scheduling algorithm is proposed.The algorithm calculates neighbors' priority based on peers' historical service evaluation as well as how many wanted data that the neighbor has.The data request allocated to each neighbor is adjusted dynamically according to the priority when scheduling.Peers with high priority are preferred to allocate more data request.Experiment shows the algorithm can make full use of neighbors' bandwidth resources to transmit data to reduce server pressure effectively and improve system scalability.
文摘The economic regionalization practice led by China local governments has gradually evolved into chaos. Local governments compete to declare for higher-leveled and large-scaled economic regions to obtain more economic resources and policy support in the way of policy game. The author argues that the regionalization chaos is attributed to the reason that the present theoretical support for economic regionalization overemphasizes the economic growth brought about by the economic regionalization but ignores the effect of transaction cost, which leads to constraint loss on the economic regionalization theory analysis framework. Then, the introduction of economic regionalization analysis framework based on the conflicts between scale expansion and transaction costs would establish equilibrium conditions to set up a moderate scale development for economic regions. The author hopes that the acceptance of this framework into the economic regionalization decision-making system would give guidance for making more appropriate regionalization decisions.
