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1.
COMPLEX ECO-ECONOMY SYSTEM   总被引:4,自引:0,他引:4  
In the past there were a lot of researches on the topic of economic growth. Nevertheless, the environment has been a bit abstracted by standard economics. Scarce natural resources and our choices to protect them or exploit them jointly determine the economic and environmental systems. In this paper we describe a model with a particular focus on the relationship among income, pollution, and non-renewable resources. We want to combine both economic and environmental sectors. The system dynamics approach is used in analyzing these complex relationships. This paper gives an insight into the possibilities for replacing non-renewable resources with more renewable ones. Next, we present the simulation runs of the model that are conducted with the help of existing system dynamics modeling tools. Only the relationships simulated so far between the variables ought to be put under yet more cautious examination.  相似文献   

2.
BOTTLENECKS IN PRODUCTION NETWORKS: AN OVERVIEW   总被引:1,自引:0,他引:1  
1. Introduction Performances of a production system, such as the throughput, the circle time and the average delay, etc., are affected by the capacities of machines and resources available in the system. Some of them may affect the system performances more than others. Usually, the limitation of a system can be traced to the limitation of one or two machines or one or two kinds of resources, commonly called bottlenecks. From system point of view, bottlenecks are the congestion points of the sy…  相似文献   

3.
A kind of networked control system is studied; the networked control system with noise disturbance is modeled based on information scheduling and control co-design. Augmented state matrix analysis method is introduced, and robust fault-tolerant control problem of networked control systems with noise disturbance under actuator failures is studied. The parametric expression of the controller under actuator failures is given. Furthermore, the result is analyzed by simulation tests, which not only satisfies the networked control systems stability, but also decreases the data information number in network channel and makes full use of the network resources.  相似文献   

4.
The problem of stochastically allocating redundant com- ponents to increase the system lifetime is an important topic of reliability. An optimal redundancy allocation is proposed, which maximizes the expected lifetime of a reliability system with sub- systems consisting of components in parallel. The constraints are minimizing the total resources and the sizes of subsystems. In this system, each switching is independent with each other and works with probability p. Two optimization problems are studied by an incremental algorithm and dynamic programming technique respectively. The incremental algorithm proposed could obtain an approximate optimal solution, and the dynamic programming method could generate the optimal solution,  相似文献   

5.
Networked control systems(NCSs) are facing a great challenge from the limitation of network communication resources. Event-triggered control(ETC) is often used to reduce the amount of communication while still keeping a satisfactory performance of the system, by transmitting the measurements only when an event-triggered condition is satisfied. However, some network-induced problems would happen inevitably, such as communication delay and packet loss, which can degrade the control performance significantly and can even lead to instability. In this paper, a periodic eventtriggered NCS considering both time-varying delay and packet loss is studied. The system is discretized into a piecewise linear system with uncertainty. Then the model is handled by a polytopic overapproximation method to be more suitable for stability analysis. Finally, stability conditions are obtained and presented in terms of linear matrix inequalities(LMIs). The result is illustrated by a numerical example.  相似文献   

6.
This paper is devoted to studying the uniqueness and existence of the system dynamic solution by using Co-semigroup theory and discussing its exponential stability by analyzing the spectral distribution of system operator and its quasi-compactness.Some primary reliability indices are discussed with the eigenfunction of system operator and the optimal vacation time to get the maximum system profit is analyzed at the end of paper.  相似文献   

7.
A robust adaptive trajectory linearization control (RATLC) algorithm for a class of nonlinear systems with uncertainty and disturbance based on the T-S fuzzy system is presented. The unknown disturbance and uncertainty are estimated by the T-S fuzzy system, and a robust adaptive control law is designed by the Lyapunov theory. Irrespective of whether the dimensions of the system and the rules of the fuzzy system are large or small, there is only one parameter adjusting on line. Uniformly ultimately boundedness of all signals of the composite closed-loop system are proved by theory analysis. Finally, a numerical example is studied based on the proposed method. The simulation results demonstrate the effectiveness and robustness of the control scheme.  相似文献   

8.
1. INTRODUCTION Decision Support System(DSS) was presented by Scott Morton in his paper entitled as “Management Decision Systems” in the early 1970’s. Until the 1980’s, DSS had become a new interdiscipline involved computer science, operational research and managerial science. The definition for DSS presented by Gorry and Scott Morton is that DSS combines personal resources with computer’s abilities so as to improve the quality of decisions. And it is an assistant system bas…  相似文献   

9.
On Fixed Points of Linguistic Dynamic Systems   总被引:4,自引:0,他引:4  
1 Introduction1 Humans employ mostly words in computing and reasoning arriving at conclusions expressed as words from premises expressed in a natural language. When we deal with a special type of dynamic system that modeled by 搘ords? we use the theory of linguistic dynamic systems (LDS) by Wang[17, 18]. This is true especially when we deal with social or economic, rather than engineering or physical systems. For many large complex systems, however, due to the complexity involved and the in…  相似文献   

10.
The hesitant fuzzy set(HFS) is an important tool to deal with uncertain and vague information.In equipment system portfolio selection, the index attribute of the equipment system may not be expressed by precise data;it is usually described by qualitative information and expressed as multiple possible values.We propose a method of equipment system portfolio selection under hesitant fuzzy environment.The hesitant fuzzy element(HFE) is used to describe the index and attribute values of the equipment system.The hesitation degree of HFEs measures the uncertainty of the criterion data of the equipment system.The hesitant fuzzy grey relational analysis(GRA) method is used to evaluate the score of the equipment system, and the improved HFE distance measure is used to fully consider the influence of hesitation degree on the grey correlation degree.Based on the score and hesitation degree of the equipment system,two portfolio selection models of the equipment system and an equipment system portfolio selection case is given to illustrate the application process and effectiveness of the method.  相似文献   

11.
土地资源是经济发展的基础,随着社会经济的不断发展,土地问题已成为影响农业乃至整个国民经济发展的重要因素。以甘肃省定西市为研究区域,采用二元相关分析法与一元线性回归相结合的方法,对1996-2005年间的社会经济发展与土地利用变化进行相关性分析。研究表明土地利用与社会经济间存在一种必然的逻辑关系,社会经济发展是定西市土地利用变化的主要驱动因素;同时提出对策,有助于加强土地在宏观调控中的作用。  相似文献   

12.
河南省耕地集约利用时空分异及驱动因素研究   总被引:6,自引:1,他引:5  
通过建立耕地集约利用评价模型和采用灰色关联分析与多元回归分析方法,对河南省耕地集约利用时空分异及其驱动因素进行了分析。结果表明河南省耕地集约利用水平自2000年以来呈不断增长趋势,省域范围内耕地集约利用差异较大,差异原因主要是由于区域农业投入产出差异所致;政策、政府、农民和科技是河南省耕地集约利用水平的主要驱动力;农业从业人口与耕地集约利用呈负相关关系,主要是科技水平和农业机械化水平的提高,大批农业劳动力被解放出来的原因。图1,表5,参7。  相似文献   

13.
且末绿洲耕地变化与驱动力研究   总被引:1,自引:0,他引:1  
利用且末绿洲多年的调查资料和统计资料,对该地区耕地资源利用和变化的基本特征、数量变化的基本过程、空间差异以及耕地变化主要驱动因子进行了分析.结果表明:近20年来,且末绿洲耕地面积呈不断扩大趋势,由于人口的持续增长造成人均耕地面积呈现下降的态势;且末绿洲耕地变化的主要因素是社会经济的发展,从单一因子考虑主要是由于人口数量增加的驱动.对于且末绿洲的可持续发展,认为应该进一步做好农业产业结构优化,加快城市化进程,加强生态环境的建设工作.图1,表4,参17.  相似文献   

14.
基于熵权TOPSIS模型的天水市土地利用结构合理性评判   总被引:2,自引:0,他引:2  
利用天水市1996—2007年土地利用变化调查数据,采用熵权TOPSIS方法对天水市土地利用结构的合理性进行了综合评价。结果表明:①1996—2007年期间天水市土地利用结构合理度总体上较高,均在90%以上,在时间上的变化呈波动趋势,并且可以明显地分为3个变化阶段。②不同土地利用类型的变化对土地利用结构的合理性影响不同,居民点及工矿用地、牧草地、交通用地与土地利用结构合理度的关联度最高。③控制交通用地和居民点及工矿用地的过快增长,严格保护水域,调整牧草地的比例,对优化天水市土地利用结构具有决定性的作用。④该方法计算简便,思路清晰,结果令人满意。适合于土地利用结构合理度评价。图2,表4,参9。  相似文献   

15.
以广西平果铝土矿区为研究对象,分析矿区的土地利用结构现状及存在的主要问题,提出土地利用结构调整方案;在此基础上构建了耕地总量动态平衡综合指数,并对矿区的耕地总量情况进行了定量评价。结果表明:矿区的耕地总量已从1995、2002年的极不平衡状态提高到了2008的不平衡状态。随后分析了影响矿区耕地总量变化的因素及矿区实现耕地总量动态平衡的可行性与潜力,最后提出了实现矿区耕地总量动态平衡的对策。土地利用结构调整方案及耕地总量动态平衡的定量评价结果可为地方政府制定耕地总量动态平衡实施措施提供科学依据,并有利于平果铝矿区土地资源的可持续开发与利用。表6,参22。  相似文献   

16.
主成分分析与系统聚类法在农业用地优先度评价中的应用   总被引:3,自引:0,他引:3  
农业用地在土地利用中占了主导地位,是进行农业各部门生产的基本生产资料,因此合理开发农业土地资源,提高土地的利用率,实现农业的可持续发展,具有极其重要的意义。利用主成分分析和系统聚类法对山东省农业用地的影响因素进行分析,找出在农业用地上起主导作用的因素,为农业用地的合理利用提供一个理论依据,并从中分析出农业用地比较合理的城市,为其他城市农业用地的改革与发展提供一些较好的例子。两种方法的综合利用能更好更科学地反映山东省农业用地的真实情况,为理论的发展和决策的实现提供了很好的理论工具。图1,表4,参7。  相似文献   

17.
基于分形理论的北京市土地利用空间格局变化研究   总被引:20,自引:0,他引:20  
为了增进对土地利用空间格局变化理解,以分形理论为指导,在遥感和地理信息技术的支持下,对北京市土地利用空间格局的变化进行了研究.首先对来自遥感影像建立起的北京市土地利用空间数据库进行提取,然后运用土地利用空间格局的分形模型,获得了1995年和2000年两个时期各个土地类型的分形维数和不稳定性指数,并且参照了常用的景观指数——多样性指数、破碎度指数和分离度指数,对土地利用空间格局变化进行了定量分析,为区域土地资源合理利用以及区域景观格局的持续发展提供了若干参考.  相似文献   

18.
长江三角洲土地资源利用与农业持续发展研究   总被引:5,自引:1,他引:4  
长江三角洲土地资源紧缺,经济快速发展过程中土地的非农化速度很快。作为我国历史上的重点农业区,尤其是我国难得的大面积粮食高产区,保护耕地与建设占地之间的矛盾随着人口、经济高速增长将日益尖锐,不解决这个问题就无从谈土地的可持续利用,就可能有农业的可持续发展,在认清土地资源开发利用的现状及其严峻态势基础上,对土地资源利用与农业发展中存在的问题进行了深入分析,阐述了21世纪持续发展的途径与对策。表2,参4。  相似文献   

19.
张掖市统筹土地利用分区研究   总被引:1,自引:0,他引:1  
土地分区是实现统筹区域土地利用的重要手段,利用主成分分析法对张掖市各乡镇的土地利用程度进行综合评价,采用空间聚类法进行综合分区,利用GIS空间分析方法进行管制分区,将张掖市划分为4个土地利用区和7个管制区。在此基础上,提出各分区内土地利用方的方向、战略对策和管制措施,为区域土地利用规划、生态环境保护与建设规划的编制提供科学依据。图5,表2,参5。  相似文献   

20.
产业结构的演变是经济和非经济的因素综合作用的结果,区域产业结构和土地利用变化之间存在着内在的联系。采用灰色关联分析方法,以德州市产业结构与土地利用之间的互动关系为例,对产业结构与土地利用关系的方法进行了探索。结果表明,产业结构与土地利用之间的关系在一定经济发展阶段可以定量测度。德州市工业化进入了中期阶段,第一产业对未利用地和耕地影响最显著,第二产业对交通用地影响最强烈,第三产业对交通用地和居民用地及工矿用地面积影响最明显;土地总体利用对产业结构的影响程度排序为第三产业、第二产业、第一产业。并相应地提出了土地合理利用建议。  相似文献   

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