The purposes of this paper are to bring land factor into the general fame of national product and develop a new modified‘IS-LM equilibrium model',aiming to find out the impacts of land factor on the effective all...The purposes of this paper are to bring land factor into the general fame of national product and develop a new modified‘IS-LM equilibrium model',aiming to find out the impacts of land factor on the effective allocation of capital between total supply and total demand constituting gross national product,to analyze the relation mechanism among land factor and macroeconomic variables,and to discuss the theoretical mechanism under which land,fiscal and monetary policy are integrated. Methods employed include econometrics and model analysis. The results indicate that:( i) on the conditions that the equilibrium of supply and demand in land market,the modified IS-LM model taking into account land factor successfully performs transmission mechanism of land policy participation in macroeconomic-control by means of money capital regulation;( ii) the direction and intensity of land policy control are effected by elasticity of land supply and land price,meanwhile different characteristics of land supply elasticity exit in different stages of economic development;( iii) the realization of IS-LM equilibrium requires the aggregate effects of fiscal,monetary and land policy. It is concluded that land policies for macroeconomic-control drives land price higher,and land supply regulation would diminish financial effect. During the economic expansion or recovery period,the effect of expansionary land policy would be counteracted by high land price. During the economic transition or recession period,the government could control economical operation better through tightening land policy.展开更多
For most firms,especially the small-and medium-sized ones,the operational decisions are affected by their internal capital and ability to obtain external capital.However,the majority of the current studies on dynamic ...For most firms,especially the small-and medium-sized ones,the operational decisions are affected by their internal capital and ability to obtain external capital.However,the majority of the current studies on dynamic inventory control ignore the firm’s financial status and financing issues completely.An important question that arises is:what are the dynamic optimal inventory and financing policies for firms with limited capital and limited access to external capital?In this paper,we review some of the latest developments in this area.After a brief review of single period models,we focus on multi-period dynamic control of the firm who aims to optimize its xpected terminal wealth.Two cases are discussed in detail:self-finance and short term finance.In the first case,the firm has to rely on its own capital for all ordering decisions,while in the second,the firm can borrow short term loan from lenders.A detailed characterization of the optimal policy is presented and its managerial insights are discussed.Several possible extensions are suggested.展开更多
访问控制是应用系统中的重要问题之一。传统的基于角色的访问控制(RBAC)方案需要预先定义和同步用户-角色赋值关系,这会带来管理成本和同步开销,并且限制了应用系统的灵活性和动态性。文章提出一种基于策略的动态角色分配模型(Policy-ba...访问控制是应用系统中的重要问题之一。传统的基于角色的访问控制(RBAC)方案需要预先定义和同步用户-角色赋值关系,这会带来管理成本和同步开销,并且限制了应用系统的灵活性和动态性。文章提出一种基于策略的动态角色分配模型(Policy-based Dynamic Role Assignment Model——PDRA),它无需同步用户就可以自定义角色,并通过策略匹配的方式实现动态分配。模型完全兼容RBAC,可以成为RBAC良好的扩展机制。文章给出了模型的定义和算法,评估了模型的性能,并在华东师范大学的数据治理平台中进行了应用,验证了该方案的可行性和有效性。展开更多
To develop a sound ozone(O_3) pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the "Sh...To develop a sound ozone(O_3) pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the "Shunde" city as a pilot summer case study,we apply an innovative response surface modeling(RSM) methodology based on the Community Multi-Scale Air Quality(CMAQ) modeling simulations to identify the O_3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O_3 impacts of volatile organic compound(VOC) control strategy.Our results show that Shunde is a typical VOC-limited urban O_3 polluted city.The "Jiangmen" city,as the main upper wind area during July 2014,its VOCs and nitrogen oxides(NO_x) emissions make up the largest contribution(9.06%).On the contrary,the contribution from local(Shunde) emission is lowest(6.35%) among the seven neighbor regions.The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde.The results of dynamic source contribution analysis further show that the local NO_x control could slightly increase the ground O_3 under low(10.00%) and medium(40.00%)reduction ratios,while it could start to turn positive to decrease ground O_3 under the high NO_x abatement ratio(75.00%).The real-time assessment of O_3 impacts from VOCs control strategies in Pearl River Delta(PRD) shows that the joint regional VOCs emission control policy will effectively reduce the ground O_3 concentration in Shunde.展开更多
基金Supported by the National Social Science Foundation of China Youth Project(13CJL064)Beijing Philosophy and Social Science Planning Project(13JGC097)
文摘The purposes of this paper are to bring land factor into the general fame of national product and develop a new modified‘IS-LM equilibrium model',aiming to find out the impacts of land factor on the effective allocation of capital between total supply and total demand constituting gross national product,to analyze the relation mechanism among land factor and macroeconomic variables,and to discuss the theoretical mechanism under which land,fiscal and monetary policy are integrated. Methods employed include econometrics and model analysis. The results indicate that:( i) on the conditions that the equilibrium of supply and demand in land market,the modified IS-LM model taking into account land factor successfully performs transmission mechanism of land policy participation in macroeconomic-control by means of money capital regulation;( ii) the direction and intensity of land policy control are effected by elasticity of land supply and land price,meanwhile different characteristics of land supply elasticity exit in different stages of economic development;( iii) the realization of IS-LM equilibrium requires the aggregate effects of fiscal,monetary and land policy. It is concluded that land policies for macroeconomic-control drives land price higher,and land supply regulation would diminish financial effect. During the economic expansion or recovery period,the effect of expansionary land policy would be counteracted by high land price. During the economic transition or recession period,the government could control economical operation better through tightening land policy.
基金Supported by National Natural Science Foundation of China(Grant No.71390330)
文摘For most firms,especially the small-and medium-sized ones,the operational decisions are affected by their internal capital and ability to obtain external capital.However,the majority of the current studies on dynamic inventory control ignore the firm’s financial status and financing issues completely.An important question that arises is:what are the dynamic optimal inventory and financing policies for firms with limited capital and limited access to external capital?In this paper,we review some of the latest developments in this area.After a brief review of single period models,we focus on multi-period dynamic control of the firm who aims to optimize its xpected terminal wealth.Two cases are discussed in detail:self-finance and short term finance.In the first case,the firm has to rely on its own capital for all ordering decisions,while in the second,the firm can borrow short term loan from lenders.A detailed characterization of the optimal policy is presented and its managerial insights are discussed.Several possible extensions are suggested.
文摘访问控制是应用系统中的重要问题之一。传统的基于角色的访问控制(RBAC)方案需要预先定义和同步用户-角色赋值关系,这会带来管理成本和同步开销,并且限制了应用系统的灵活性和动态性。文章提出一种基于策略的动态角色分配模型(Policy-based Dynamic Role Assignment Model——PDRA),它无需同步用户就可以自定义角色,并通过策略匹配的方式实现动态分配。模型完全兼容RBAC,可以成为RBAC良好的扩展机制。文章给出了模型的定义和算法,评估了模型的性能,并在华东师范大学的数据治理平台中进行了应用,验证了该方案的可行性和有效性。
基金Financial support for this work is provided by the Shunde Environment ProtectionTransportation and Urban Administration Bureau(no.0851-1361FS02CL51)+5 种基金the Guangdong Provincial Science and Technology Plan Projects(no.2014A050503019)Guangzhou Environmental Protection Bureau(no.x2hjB2150020)supported by the funding of State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complexthe project of Atmospheric Haze Collaboration Control Technology Design(no.XDB05030400)from Chinese Academy of Sciencesthe Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(U1501501)(the second phase)the Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal(no.b2152120)
文摘To develop a sound ozone(O_3) pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the "Shunde" city as a pilot summer case study,we apply an innovative response surface modeling(RSM) methodology based on the Community Multi-Scale Air Quality(CMAQ) modeling simulations to identify the O_3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O_3 impacts of volatile organic compound(VOC) control strategy.Our results show that Shunde is a typical VOC-limited urban O_3 polluted city.The "Jiangmen" city,as the main upper wind area during July 2014,its VOCs and nitrogen oxides(NO_x) emissions make up the largest contribution(9.06%).On the contrary,the contribution from local(Shunde) emission is lowest(6.35%) among the seven neighbor regions.The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde.The results of dynamic source contribution analysis further show that the local NO_x control could slightly increase the ground O_3 under low(10.00%) and medium(40.00%)reduction ratios,while it could start to turn positive to decrease ground O_3 under the high NO_x abatement ratio(75.00%).The real-time assessment of O_3 impacts from VOCs control strategies in Pearl River Delta(PRD) shows that the joint regional VOCs emission control policy will effectively reduce the ground O_3 concentration in Shunde.