Computation of non-linear continuous optimal growth models: experiments with optimal control algorithms and computer programs

In this paper we discuss the use of optimal control methods for computing non-linear continuous optimal growth models. We have discussed various recently developed algorithms for computing optimal control, involving step-function approximations, Runge–Kutta solutions of differential equations, and we suggest that the discretization approach is preferable to methods which solve first-order optimality conditions. We have surveyed some powerful computer programs by : , and for computing such models numerically. These programs have no substantial optimal growth modelling applications yet, although they have numerous engineering and scientific applications. A computer program named by is developed in this study. Results are reported for computing the Kendrick–Taylor optimal growth model using and programs based on the discretization approach. References are made to the computational experiments with and . The results are used to compare and evaluate mathematical and economic properties, and computing criteria. While several computer packages are available for optimal control problems, they are not always suitable for particular classes of control problems, including some economic growth models. The -based and , however, offer good opportunities for computing continuous optimal growth models. It is argued in this paper, that optimal growth modellers may find that these recently developed algorithms and computer programs are relatively preferable for a large variety of optimal growth modelling studies.     

From pond to plate: Towards a twin-driven commodity chain in Bangladesh shrimp aquaculture

Globalization of the agro-food system has led developing nations to orient their production to meet global markets. Consequently, local agricultural systems are increasingly linked to global commodity networks, and generate complex intersections and sometimes tensions. Cultured shrimp in Bangladesh is such a global commodity that connects the local producers with the global consumers starting from pond to plate via a network of diverse actors in a complex manner. Field research in Bangladesh shows that shrimp aquaculture in Bangladesh is moving towards a twin-driven commodity chain in which lead firms govern supply network, while the Shrimp Seal of Quality Organization (SSOQ), a recently emerged third-party certifier, as well as other environmental NGOs define regulatory aspects of the industry. While governance in twin-driven commodity chain offers opportunities for a sustainable aquaculture, it also poses many questions which have significant policy implications for different stakeholders involved in the chain.     

构建和谐社会视角下的新疆居民收入差距探析

改革开放以来,新疆居民收入普遍大幅度增加,各个阶层群众都获得了改革开放带来的实惠。同时,收入格局也发生了深刻的变化,居民收入差距尤其是城乡之间、地区之间、行业之间的居民收入差距急剧扩大。本文对新疆居民收入差距的现状及产生的原因进行了分析,在此基础上提出了缩小地区收入差距,构建社会主义和谐新疆的对策建议。     

Wealth inequality,democracy and economic freedom

Using a novel panel data set from the Credit Suisse on the top wealth shares for 46 sample countries spanning 2000–2014, this paper empirically investigates to what extent wealth inequality influences economic freedom and whether this relationship is affected by the level of democracy. Economic freedom is measured by the Fraser Institute's economic freedom summary index as well as its five major sub-indices, such as government size, property rights, access to sound money, freedom to trade, and regulations. Wealth inequality is measured by the top wealth shares. Trade union density is used as an instrument for wealth inequality. Empirical results suggest that the rising wealth inequality significantly hampers overall economic freedom, property rights protection, freedom to trade, soundness of money and regulatory environment. Furthermore, this negative effect of wealth inequality is reinforced at a lower level of democracy. These findings are robust to alternative measures of wealth inequality, economic freedom, treatment for endogeneity, and model specification.     

Financial market development and the importance of internal cash: Evidence from international data

We examine the impact of financial market development on the extent to which firms have to rely on internal capital for making investments. Using international data from 31 countries for the 1987–1997 period, we find evidence of a negative relationship between financial market development and the importance of internal capital. The evidence is consistent across different estimation procedures, alternative measures of financial constraints and cash flow, and the use of bootstrapped standard errors. Finally, we find that the distortionary effect of negative cash flow observations reported earlier for US data extends to international data as well.     

Japanese Banks—A Risk Factor for the Japanese Economy

Original Papers

Japanese Banks—A Risk Factor for the Japanese Economy     

Modelling the dependence between the times to international adoption of two related technologies

The structure of the dependence between the times to adoption by a country of two related innovations, the fax and the cellular telephone, is modelled in two stages. The first stage is the choice of density function for the time to adoption. The second stage is describing the dependence relation. For the first stage, a Weibull density function is used with its scale factor adapted to account for the economic and technological environments in different countries. Environmental data are collected from several sources. Copulas are used to model the dependence relation, three single parameter copulas are considered, those due to Farlie-Gumbel-Morgenstern (FGM), Frank and Plackett. Their properties are described and a combined estimation of the copula and density function parameters carried out. The limitations of the FGM copula rule it out from further consideration. The other copulas coupled with the Weibull, using eight environmental variables, are shown to provide valuable insights into the effects of environmental variables on adoption times. Given that a country has adopted one technology, the model of the dependence relation is used to provide the conditional density of the time to adoption of the other technology.