Uncertain Climate Change in an Intergenerational Planning Model

A three-generation planning model incorporating uncertain climate change is developed. Each generation features a production activity based on capital and an exhaustible resource. An irreversible climate change may occur in period two or three, reducing the productivity for this and the remaining generation. The model is solved by stochastic dynamic programming. If the climate impact and climate change probability is constant, the optimal period one (and two) resource extraction is larger than for the reference case of climate stability. If, however, climate impact and climate change probability increases with increased aggregate resource use, this result is reversed.     

20世纪90年代以来中国经济的动态效率

本文借助于西方宏观经济学中的索洛经济增长模型和拉姆齐 卡斯 库普曼斯模型 ,讨论了宏观经济中最优消费和储蓄的确定机制 ,并得出判断宏观经济运行动态效率的黄金定律以及修正黄金定律标准。同时 ,借助代际交叠模型从理论上探讨了自由竞争经济出现动态无效的可能性。在此基础上 ,我们利用黄金定律规则对中国实际经济运行的动态效率进行了考察 ,认为 2 0世纪 90年代初起中国经济运行处于一种动态无效状态 ,进而我们深入分析了造成中国经济出现动态无效的原因。根据中国经济处于动态无效的事实 ,并结合原因探索 ,我们最后提出了摆脱动态无效困境的若干政策建议。     

城市生态学视野下的动态适度人口规模——兼论上海人口发展的基本态势

提出城市适度人口规模不是一个静态的数值,而是动态的过程。不是一个先验的数值,而是系统决定的综合结果。建立了一个适度人口规模的概念性框架,即EFL模型,就是说合理和适度的人口规模是与之相联系的资源环境因素、功能和经济方式、空间区位状态共同决定的结果。生态系统的变动,综合决定了一定时期、一定标准下的城市人口适度规模,并决定了这一适度规模的变化趋势。基于这一思路,讨论了影响上海人口规模变动的积极因素和阻碍因素,从资源环境变化、城市功能变化和城市空间变化三个方面对上海适度人口规模的变动趋势作了基本判断,提出上海人口规模将出现先上升再下降的趋势。根据动态适度人口规模的观点,对城市人口综合调控和城市管理的有关问题提出了一些建议。     

产业结构软化及其对世界经济发展的影响

产业结构的状态总是随着经济发展的变化而处于不断变动之中。20世纪中期以来，以信息技术革命为核心的新技术革命的兴起加速了世界产业结构的全方位变革，出现了产业结构软化的趋势。产业结构软化趋势主要表现为产业结构服务化、高技术化、融合化和国际化，它是世界经济发展的必然结果，同时又对世界经济发展产生了重要的影响。     

我国上市公司再融资与财务业绩动态变化研究

本文对上市公司再融资的3种形式及对财务业绩在时间上的变化进行了分析，提出了无论配股、增发新股、发行可转换债3种方式对财务指标的影响是下滑的，而对企业的核心业务是增强的，但不显著。发行可转债优于配股和增发。     

美国GE公司CEO继任规划的启示

继任规划在企业追求长期战略和持久业绩的过程中起着关键作用。而CEO继任规划则是企业最重大的战略决策。美国GE公司由于建立了一套行之有效的CEO继任规划程序，从而保证企业能够培养合适的CEO候选人。公司CEO继任规划包括内部接班继任、内部竞争继任、突然政变继任和广泛选择继任等4种方式。每一种继任方式都有其优势和劣势。不存在适用于所有公司的继任方式。不同的公司如何选择适合的继任方式取决于公司本身的条件。目前，我国企业正在进入经营者大换班高峰期，可以借鉴美国GE公司CEO继任规划的成功经验，进一步完善继任机制。     

新围海涂土地利用结构优化模型及其应用

为了进一步探讨数学规划模型在新围海涂土地利用结构优化中的应用,在模型分析与实例应用相结合的基础上,选择浙江沿海新围海涂作为典型研究区,根据当地滩涂开发利用总体规划要求,结合实际开发需要,应用数学规划方法构建土地利用结构优化决策模型,对规划范围内新围海涂的土地利用结构进行优化配置。研究结论:应用数学模型对研究区内土地利用结构优化配置是可行的。但是今后需要进一步研究空间优化配置方法,实现定性、定量和定位三者的统一。     

Portfolio Optimization under Lower Partial Risk Measures

Portfolio management using lower partial risk (downside risk) measures is attracting more attention of practitioners in recent years. The purpose of this paper is to review important characteristics of these riskmeasures and conduct simulation using four alternative measures, lower semi-variance, lower semi-absolute deviation, first order below targetrisk and conditional value-at-risk.We will show that these risk measures are useful to control downside risk whenthe distribution of assets is non-symmetric. Further, we will propose a computational scheme to resolve the difficultyassociated with solving a large dense linear programming problems resulting from these models. We will demonstrate that this method can in fact solve problems consisting of10⁴ assets and 10⁵ scenarios within a practical amount of CPU time.     

Experimental Economics and the Theory of Decision Making Under Risk and Uncertainty

Following a brief review of the main experimental work into the economics of risk and uncertainty, both static and dynamic, this paper reports the results of an experiment testing one of the key assumptions of the theory of dynamic economic behaviour—that people have a plan and implement it. Using a unique design which enables the plan (if one exists) to be revealed by the first move, the experiment was implemented via the Internet on a subset of the University of Tilburg's ongoing family expenditure survey panel. The advantages of using such a set of subjects for the experiment are twofold: the demographic characteristics of the set are known and therefore demographic inferences can be made; the representativeness of the set is known and therefore inferences about populations can be made. The results suggest that at least 36% of the subjects had behaviour inconsistent with the hypothesis under test: that people formulate plans and then implement them. Interestingly demographic variables are unable to explain the consistency or inconsistency of individuals. One conclusion is that subjects simply make errors. An alternative conclusion, consistent with previous experimental research, is that people are unable to predict their own future decisions. The implications for dynamic theory (particularly relating to savings and pensions decisions) are important.     

Planning Your Own Debt

We model the Danish market for mortgage backed securities with a two-factor interest rate model and use a stochastic programming approach to analyse how an individual home-owner should initially compose and subsequently readjust his mortgage in an optimal way. Results show that the 'rules of thumb' used by financial institutions are reasonable, although best suited for more aggressive mortgagors, for whom the delivery option is of some value. More risk-averse investors should also re-adjust frequently, but use more diversified portfolios. Results are insensitive to whether a one- or two-factor model is used, provided the former is suitably calibrated.