EMPIRICAL PERFORMANCE OF GARCH MODELS WITH HEAVY‐TAILED INNOVATIONS

We introduce a new type of heavy‐tailed distribution, the normal reciprocal inverse Gaussian distribution (NRIG), to the GARCH and Glosten‐Jagannathan‐Runkle (1993) GARCH models, and compare its empirical performance with two other popular types of heavy‐tailed distribution, the Student's t distribution and the normal inverse Gaussian distribution (NIG), using a variety of asset return series. Our results illustrate that there is no overwhelmingly dominant distribution in fitting the data under the GARCH framework, although the NRIG distribution performs slightly better than the other two types of distribution. For market indexes series, it is important to introduce both GJR‐terms and the NRIG distribution to improve the models’ performance, but it is ambiguous for individual stock prices series. Our results also show the GJR‐GARCH NRIG model has practical advantages in quantitative risk management. Finally, the convergence of numerical solutions in maximum‐likelihood estimation of GARCH and GJR‐GARCH models with the three types of heavy‐tailed distribution is investigated.     

Markets and pro-poor agricultural growth: insights from livelihood and informal rural economy models in Malawi

This article presents the development of a set of programming models describing the major features of different rural livelihoods and of the informal rural economy they together make up in Malawi. The models allow for differentiated responses by different household types to change and for the partial equilibrium effects of consequent supply, demand, and price adjustments in labor and grain markets. The models provide insights into the relations between own‐farm and nonown‐farm activities in different households' livelihoods and in the informal rural economy as a whole, and are used to investigate possible impacts of increasing cash crop prices and of a more open rural economy. Impacts of these changes on the poor are found to be critically dependent upon supply and demand elasticities in labor and grain markets, but the poor could potentially suffer significant losses from increased openness of the local economy leading to increased expenditure by less poor households on imported goods and services.     

The dynamics of moonlighting in Russia1

This paper uses the Russian Longitudinal Monitoring Survey (RLMS) to analyse the dynamics of moonlighting by the working‐age population. We find that moonlighting is transitory and that a desire to switch jobs expressed in the past is positively related to moonlighting in the present and to actual job changes in the future. We also find that workers who moonlighted as self‐employed in the past represent 26.5 percent of the new self‐employed. These results suggest that moonlighting in Russia can be seen as an effective incubator for setting up new self‐employed businesses, thereby providing long‐term benefits for the economy.     

英国养老保险制度浅析

英国是世界上最早建立社会保障制度的国家之一。英国建立的多层次养老体系以及一直贯彻的“普遍性”原则、“最低”原则和“个人责任”原则，值得我们这样一个发展中的经济转型国家研究和借鉴。     

REVISITING INFORMAL EMPLOYMENT AND SEGMENTATION IN THE SOUTH AFRICAN LABOUR MARKET

This study revisits the definition of informal employment, and it investigates the puzzle of high open unemployment co‐existing with relatively limited informal employment in South Africa. We estimate earnings equations using data from the September 2004 Labour Force Survey and present evidence of persistent earnings differentials not only between formal and informal employment, but also between types of informal employment. These persistent earnings differentials are suggestive of complex segmentation in the South African labour market and challenge the presentation of informal employment as an undifferentiated residual with no barriers to entry or mobility.     

Decentralizing antipoverty program delivery in developing countries

We study the effects on accountability in government service delivery of decentralizing administration of an antipoverty program. While governments at both central and local levels are vulnerable to antipoor policy biases owing to political capture, centralized delivery systems are additionally prone to bureaucratic corruption, owing to problems in monitoring bureaucratic performance. Decentralizing the delivery system promotes cost-effectiveness and improves intraregional targeting at low program scales. But interregional targeting may deteriorate, as central grants to high-poverty regions shrink, owing to high capture of local governments by local elites in such regions.     

Welfare effects of 1992: A general equilibrium assessment for EC and EFTA countries

In this paper production, trade and welfare effects of European integration are discussed, with particular emphasis on the effects for the EC and EFTA. Insights from previous partial and general equilibrium analyses of the internal market are reviewed, and new model simulations are presented. In addition to the standard experiments of 1992 — as reduced trade costs and as full market integration — for the EC alone, and for the European Economic Area (EEA), an intermediate case, with full integration in the EC but only lower trade costs between the EC and EFTA, is analysed. All cases show that EFTA will benefit significantly from freer trade and closer integration with the EC. With regard to non-European regions, the simulations of European integration show some degree of trade diversion, but stylized model experiments indicate that a successful outcome of the Uruguay-round may more than offset the trade-diverting effects of 1992.     

无刷直流电机控制系统的建模及仿真

简要介绍了无刷直流电机的工作原理,建立了BLDCM数学模型及simulink仿真模型.仿真结果表明波形符合理论分析,系统具有良好的静、动态特性.     

电动搬运车辆斩波器的应用分析

介绍以蓄电池和串励直流电动机为动力的电动搬动车辆用斩波器的种类，型号，参数，电路原理和应用情况。     

模糊自动控制理论在高速公路机电设备中的应用

文章介绍了在直流并励电动机控制中引进模糊自动控制,可以实现电动机恒流起动、恒速运行,降低电机的故障率,保障它的运行。