Statistical efficiency in the linear combination of forecasts

In seeking an efficient combination of forecasts which minimises the forecast error variance, many methods have been suggested. Through analysis, simulation and case studies, this paper seeks to develop insights into the statistical circumstances which influence the relative accuracy of six of these methods. The six methods chosen have all been advocated in various publications and consist of ‘equal weighting’ (i.e., pooled average), ‘optimal’ (i.e., error variance minimising), ‘optimal with independence assumption’ (i.e., error variance minimising assuming zero correlation between individual forecast errors) and three variations on the formulation of a Bayesian combination based upon posterior probabilities. The statistical circumstances reflected varying conditions of relative forecast errors, error correlations and outliers.     

基于两型社会要求的武汉绿色物流发展研究

纵观国内外经济发达的地区和国家,无一例外,都是把高效环保的现代化物流作为经济发展的生命线。作为中部最为重要的城市圈之一:武汉城市圈也应基于两型社会要求向绿色物流进军。     

European financial market dependence: An industry analysis

This paper uses a copula model to investigate the degree and determinants of European market dependence across 10 industries in 12 Euro zone and 8 non-Euro zone stock markets during the period 1992–2011. Most of the industries in Euro countries show a dependence increase with the Euro-area after the introduction of the Euro. The effects are strongest in countries with larger market capitalization and in the Financials, Industrials, Consumer Goods, Utilities, Technology and Telecommunications industries. Overall, the export intensity, interest rate sensitivity and competitiveness of an industry and the financial development and economic openness of a country are the most important determinants of changes in equity market dependence. The period around the Lehman collapse also shows higher equity market dependence between European countries, while the lower dependence increase during the period of the recent European sovereign debt crisis suggests that country-specific factors may matter more than before.     

China in transition: institutional change at work in inland waterway transport on the Yangtze River

Chinese national fiscal reforms and the transfer of power from the central government to local governments impact the governance of inland waterway transport (IWT). In this paper we argue that the development of IWT on the Yangtze River is strongly influenced by institutional changes at different levels of government in line with the path dependent transformation of the Chinese centrally planned economy. This paper deduces how institutional change of IWT on the Yangtze fails to fulfil its purposes because of institutional legacies and conflicts of interests among the various levels of government and the persistent interwovenness of the state with private enterprises (via SOEs). In order to further stimulate IWT on the Yangtze more institutional changes are on the cards, in particular a need for more (foreign) private involvement and more independent SOEs, but these changes will not necessarily break out of the development path.     

Analysis of ruin measures for the classical compound Poisson risk model with dependence

In this paper, we consider an extension to the classical compound Poisson risk model. Historically, it has been assumed that the claim amounts and claim inter-arrival times are independent. In this contribution, a dependence structure between the claim amount and the interclaim time is introduced through a Farlie–Gumbel–Morgenstern copula. In this framework, we derive the integro-differential equation and the Laplace transform (LT) of the Gerber–Shiu discounted penalty function. An explicit expression for the LT of the discounted value of a general function of the deficit at ruin is obtained for claim amounts having an exponential distribution.     

Co-evolution of trust and dependence in customer–supplier relationships

The relational and dynamic aspects of interfirm trust and dependence produce a crucial, but insufficiently addressed, challenge for successful relationship coordination. In this paper we concentrate on this issue by examining how trust and dependence co-evolve in customer–supplier relationships. Building on a case study, we develop propositions and a model that illustrates how interorganizational trust and dependence co-evolve through the different phases of customer–supplier relationships and how we may distinguish cooperative and trustworthy actors from those who will behave opportunistically. Theoretical and practical implications are offered.     

Forest incomes and rural livelihoods in Chiradzulu District, Malawi

This paper examines forest income among rural dwellers in one of Malawi's most densely populated districts, Chiradzulu. 160 households were interviewed in two sites, only 20 km apart, purposely selected on the basis of access to a forest reserve. People are extremely poor, with 97% having incomes of less than 1 USD/day. Forest income constitutes around 15% of total income; only non-farm income (47%) and agriculture (28%) rank higher. The poorest segment depends more on forest income than the least poor group, but the medium income group exhibits the highest dependence. Fuelwood constitutes the major source of such income followed by fodder. The incomes mainly support current consumption. People with better access to the forest reserve have higher total income, forest income, and relative forest income. As revealed through a Gini-coefficient analysis, forest resources have an important income equalizing effect across rural households. A particular group of resource poor farmers (8.1% of sample), with little access to agricultural land and a high representation of female heads, derives an average of 65% of their income from the forest. An important policy lesson is that restricting people's access to forest resources can have substantial effects on household livelihoods and welfare, and would serve to increase income inequalities in the area. Livelihood researchers should now recognize the substantial income from forest resources.     

Multivariate models for operational risk

Böcker and Klüppelberg [Risk Mag., 2005, December, 90–93] presented a simple approximation of OpVaR of a single operational risk cell. The present paper derives approximations of similar quality and simplicity for the multivariate problem. Our approach is based on the modelling of the dependence structure of different cells via the new concept of a Lévy copula.     

相互依赖、信任对企业关系导向合作的影响分析

关系导向合作主要是基于效率动机、稳定动机和互惠的动机。关系导向合作是企业之间相互依赖和信任的结果;信任与企业关系导向合作之间的关系受到依赖程度的调节影响,信任对关系导向合作的影响因不同的依赖水平而不同;相互依赖程度和关系导向合作之间的关系受到信任水平的调节影响,当信任水平较低时,依赖不对称程度对关系导向合作的影响是反向的;当信任水平较高时,依赖不对称程度对关系导向合作的反向影响就会变得不明显或者甚至是正向的影响;对称的相互依赖和信任之间的互动,有利于企业长期的关系导向合作。