ON THE SUSTAINABLE GROWTH IN AN ECONOMY WITH PERFECTLY SUBSTITUTABLE EXHAUSTIBLE RESOURCES

Abstract A model of sustainable economic growth in an economy with two types of exhaustible resources is analyzed. The resources are assumed to be perfect substitutes with marginal rate of substitution varying over time. The optimal control framework is used to characterize the optimal paths under the maximin criterion. It is shown that the resource with increasing productivity is not used before the constant productivity resource is depleted. Afterwards the resource with an increasing productivity is asymptotically depleted as well. The results are based on an assumption that transversality conditions hold. A new sufficient condition for the transversality conditions is derived. Finally, an analogue of Hartwick’s rule for this non‐autonomous case is established.     

Technical change and the von Neumann coefficient of uniform expansion

We study technical change for multi-product technologies to examine its effect on economic growth for 27 OECD (Organization for Economic Cooperation and Development) countries during 1951–2014. We review the Malmquist index and reexamine von Neumann’s model of an expanding economy. We estimate the coefficient of uniform expansion via DEA (Data Envelopment Analysis) and use it to measure technical change via a Solow residual and an alternative von Neumann technical change index which equals the difference between the growth rates of the slowest growing output and the fastest growing input. We also exploit a property of constant returns to scale in order to examine technical change of the average technology. During 2005–2014 the Solow residual shows relatively fast technical change. In contrast, the Malmquist, average technology and alternative von Neumann technical change indexes show negative or stagnant technical change.     

基于Douglas生产函数的广西经济增长因素分析

基于柯布-道格拉斯(Douglas)生产函数,建立1995年至2012年广西经济发展模型,利用R统计软件求出资本和劳动力的产出弹性系数分别为0.81和0.19,再利用索洛增长速度方程求出资本投入、劳力投入和技术进步对广西经济增长的贡献率分别为141.8%、1.5%、-43.3%,这三个因素分别拉动经济增长15.8百分点、0.2百分点和-4.8百分点.表明了资本投入是广西近十几年来经济增长的决定性因素,劳动投入和技术进步对经济增长的贡献比较有限,广西的经济还是处于粗放投入型的增长模式.     

劳动力供给带弹性的Solow模型

本文给出了在劳动力供给带弹性条件下的Ｓｏ１ｏｗ增长模型，给出了经济增长的黄金律和均衡处资本稳定性的证明，并且与不带弹性的Ｓｏｌｏｗ模型作了比较．     

DEGREE OF ECONOMIC UNSUSTAINABILITY IN THE MANAGEMENT OF RENEWABLE RESOURCES

A criterion commonly used to determine economic sustainability posits that the discounted welfare should not decrease over time. Resource management problems involving fluctuating stocks may be exacerbated by a lack of sustainable policies unless some violations of this condition are accepted. Moreover, sustainable policies may lead to the minimal welfare levels. To alleviate these problems, a new notion of sustainability is suggested. In this new form of sustainability, violations of nondecreasing welfare are accepted to a certain degree. The policies that maximize the discounted welfare under the constraint for the largest accepted violation for sustainability satisfy a dynamic programming type of fixed‐point condition that can be effectively utilized for finding optimal policies. The new notion of sustainability can also be utilized in defining an index for measuring the degree of overall unsustainability of resource management problems and different harvesting policies.     

具有生产性与福利性公共支出的随机内生增长模型

文章建立一个随机内生增长模型来阐明主要政策参数对经济增长与社会福利的影响.若对生产函数、效用函数、偏好及随机干扰作一些特殊的假设,我们证明了主要政策参数的均衡值能被模型参数唯一决定.进一步我们还得到了期望增长率与储蓄的清晰解.文章的最后,我们证明了政府支出直接影响个体决策者的决策:即提高经济增长率将减少福利;反之,增加福利将减少增长率.     

资产组合,随机经济增长和政府政策的影响

本文在一个连续时间的经济增长模型中考虑政府政策、投资策略和个体福利 .在给定的生产技术 ,偏好和随机冲击的假设下 ,本文得到了持有资产税后期望回报、随机经济增长率、消费财富比、资产组合份额和各种资产实际回报率的显式解 .     

OPTIMAL HARVEST FEEDBACK RULE ACCOUNTING FOR THE FISHING‐UP EFFECT AND SIZE‐DEPENDENT PRICING

Abstract Fishing leads to truncation of a population's age and size structure. However, large‐sized fish are usually more valuable per unit weight than small ones. Nevertheless, these size‐related factors have mostly been ignored in bioeconomic modeling. Here, we present a simple extension to the Gordon–Schaefer model that accounts for variations in mean individual catch weight, and derive the feedback rule for optimal harvest in this setting. As the Gordon–Schaefer model has no population structure, size effects have to be accounted for indirectly. Here we assume a simple negative relationship between fishing effort and mean individual weight, and a positive relationship between mean catch weight and price. The aim is to emulate alterations of size structure in fish populations due to fishing and the influence of size on price per weight unit and eventually, net revenues. This demonstrates, on a general level, how such size‐dependent effects change the patterns of optimal harvest paths and sustainable revenue in single fish stocks. The model shows clear shifts toward lower levels of optimal effort and yield compared to classical models without size effects. This suggests that ignoring body size could lead to misleading assumptions and policies, potentially causing rent dissipation and suboptimal utilization of renewable resources.     

On the asymptotics of fault probability in least‐recently‐used caching with Zipf‐type request distribution

We consider the least‐recently‐used cache replacement rule with a Zipf‐type page request distribution and investigate an asymptotic property of the fault probability with respect to an increase of cache size. We first derive the asymptotics of the fault probability for the independent‐request model and then extend this derivation to a general dependent‐request model, where our result shows that under some weak assumptions the fault probability is asymptotically invariant with regard to dependence in the page request process. In a previous study, a similar result was derived by applying a Poisson embedding technique, where a continuous‐time proof was given through some assumptions based on a continuous‐time modeling. The Poisson embedding, however, is just a technique used for the proof and the problem is essentially on a discrete‐time basis; thus, it is preferable to make assumptions, if any, directly in the discrete‐time setting. We consider a general dependent‐request model and give a direct discrete‐time proof under different assumptions. A key to the proof is that the numbers of requests for respective pages represent conditionally negatively associated random variables. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006     

Numerical methods for Hamilton Jacobi functional differential equations

Initial and initial boundary value problems for first order partial functional differential equations are considered. Explicit difference schemes of the Euler type and implicit difference methods are investigated. The following theoretical aspects of the methods are presented. Sufficient conditions for the convergence of approximate solutions are given and comparisons of the methods are presented. It is proved that assumptions on the regularity of given functions are the same for both the methods. It is shown that conditions on the mesh for explicit difference schemes are more restrictive than suitable assumptions for implicit methods. There are implicit difference schemes which are convergent and corresponding explicit difference methods are not convergent. Error estimates for both the methods are construted.     

Global attractors of quasi-linear non-autonomous difference equations: A growth model with endogenous population growth

We study the global attractors of quasi-linear non-autonomous difference equations and we apply the reached results to an economic growth model of Solow type while assuming that the population growth rate is endogenous and described by the logistic equation.     

Calibration and solutions of macro-models of technology in North-South development

A model representing the economic interactions within and between regions is described which, unlike many other models concerned with aspects of global development, includes endogenous treatment of internal income distribution and international trade.¹ Following earlier analytic work, a preliminary calibration of the model is carried out and simulation experiments performed with it. Results are presented to illustrate the internal and external effects of trade, changes in technology and capital accumulation. It is suggested that some results from orthodox theory concerning, for example, the benefits of trade or of capital accumulation, are dependent on unstated assumptions which may hold only under certain economic and technical conditions.     

Efficiency and welfare implications of managed public sector hospital waiting lists

A queuing model for public health service waiting lists is developed, and the implications for patient welfare of different systems for managing the waiting list are analysed. If patients are admitted to hospital on a first-come-first-served basis, a welfare gain is achieved by moving from a system of implicit to one of explicit rationing of access to the waiting list. If individual waiting times and hospital admissions are dependent on clinical priority, a further welfare gain is achievable without the use of explicit rationing, by reallocating the total waiting time from the more towards the less seriously ill. On efficiency and welfare criteria, a maximum waiting time guarantee does not appear to be a desirable development.     

Interpretability assessment of fuzzy knowledge bases: A cointension based approach

Computing with words (CWW) relies on linguistic representation of knowledge that is processed by operating at the semantical level defined through fuzzy sets. Linguistic representation of knowledge is a major issue when fuzzy rule based models are acquired from data by some form of empirical learning. Indeed, these models are often requested to exhibit interpretability, which is normally evaluated in terms of structural features, such as rule complexity, properties on fuzzy sets and partitions. In this paper we propose a different approach for evaluating interpretability that is based on the notion of cointension. The interpretability of a fuzzy rule-based model is measured in terms of cointension degree between the explicit semantics, defined by the formal parameter settings of the model, and the implicit semantics conveyed to the reader by the linguistic representation of knowledge. Implicit semantics calls for a representation of user’s knowledge which is difficult to externalise. Nevertheless, we identify a set of properties - which we call “logical view” - that is expected to hold in the implicit semantics and is used in our approach to evaluate the cointension between explicit and implicit semantics. In practice, a new fuzzy rule base is obtained by minimising the fuzzy rule base through logical properties. Semantic comparison is made by evaluating the performances of the two rule bases, which are supposed to be similar when the two semantics are almost equivalent. If this is the case, we deduce that the logical view is applicable to the model, which can be tagged as interpretable from the cointension viewpoint. These ideas are then used to define a strategy for assessing interpretability of fuzzy rule-based classifiers (FRBCs). The strategy has been evaluated on a set of pre-existent FRBCs, acquired by different learning processes from a well-known benchmark dataset. Our analysis highlighted that some of them are not cointensive with user’s knowledge, hence their linguistic representation is not appropriate, even though they can be tagged as interpretable from a structural point of view.     

集对分析在我国经济增长模糊规则提取中的应用

针对粗糙集和模糊聚类方法提取我国经济增长模糊规则算法复杂的问题,把集对分析用于我国31个省市经济增长模糊规则提取。结果显示,不仅算法简明,而且能同时提取宏观层次上的经济增长规则—固定资产投资对GDP的拉动效果要大于人力资源对GDP的拉动效果,而且还从微观层次上揭示出各省的经济增长规则,为我国十二五经济发展规划的实施提供决策参考。     

Growth and long-run stability

This paper analyses the implications of persistent growth upon the stability properties of dynamic models. Besides the traditional concept of asymptotic stability, new stability criteria-strong/weak absolute, strong/weak relative, strong/weak logarithmic stability-are introduced, and global stability conditions for satisfying these criteria are stated for general first-order autonomous differential equations. The conflict between rapidity of growth and the degree of stability is demonstrated. Economic applications of the stability theorems are illustrated within the growth models of Harrod and Solow.     

随机变延迟微分方程平衡方法的均方收敛性与稳定性

针对一类变延迟微分方程,应用全隐式方法—平衡方法,研究了其收敛性和稳定性.结果表明平衡方法以$\frac{1}{2}\gamma,\gamma\in（0,1]$阶收敛到精确解;并且强平衡方法和弱平衡方法都能保持解析解的均方稳定性;进一步数值实验验证了算法理论分析的正确性,并且表明全隐式的平衡方法比显式方法—Euler方法具有更好的稳定性.     

管理有效性与管理贡献率的测算

生产单元的管理有效性具体体现在优化配置所有参与生产过程的物质资源和人力资源,适时调整生产规模.在这一含义之下,利用等效益面生产函数可将一个生产单元的经济增长分解为三个要素的代数和.他们分别是投入要素的贡献、技术进步和管理效应.其中管理贡献反映的是技术效率的改善,其本质就是偏要素生产率的变化和规模效应即资源配置效率.在其离散型分解式的基础上,可以根据这些要素的不同变化情况,进一步测算管理贡献率.基于等效益面生产函数上的管理贡献率测算方法同时考虑了管理有效性概念的内涵和外延,具有明确的经济意义和几何意义.     

随机Solow经济增长模型及其解的性质

１９８７年诺贝尔（Ｎｏｂｅｌ）经济学奖获得者Ｓｏｌｏｗ教授，建立了确定性的经济增长模型（１９５６年）．它比较真实地描述了现实世界申的确定性的经济增长状况，然而对不确定性的现象，往往误差较大，甚至失效．本文把Ｓｏｌｏｗ模型扩展到随机情形，扩展了Ｂａｎａｃｈ压缩映像原理和不动点定理，获得了随机Ｓｏｌｏｗ模型主要方程和随机解的一些性质．     

教育和健康对区域经济收敛的影响研究——以浙江省为例

本文基于扩展的Solow模型框架,研究了教育和健康人力资本对区域经济收敛性的影响。计量结果表明浙江区域经济在1997-2005年具有显著的条件收敛和俱乐部收敛特征,教育和健康人力资本均有利于经济收敛,且是影响区域经济收敛的一个显著要素。由于以往的研究多以教育来代理人力资本指标,本文分析表明健康对经济增长具有直接影响效应,因此人力资本指标如果仅以教育指标来代理计量,将会低估人力资本对经济增长的贡献力。