Three Corrected Score Tests for Generalized Linear Models with Dispersion Covariates

We develop three corrected score tests for generalized linear models with dispersion covariates, thus generalizing the results of Cordeiro , Ferrari and Paula (1993) and Cribari-Neto and Ferrari (1995) . We present, in matrix notation, general formulae for the coefficients which define the corrected statistics. The formulae only require simple operations on matrices and can be used to obtain analytically closed-form corrections for score test statistics in a variety of special generalized linear models with dispersion covariates. They also have advantages for numerical purposes since our formulae are readily computable using a language supporting numerical linear algebra. Two examples, namely, iid sampling without covariates on the mean or dispersion parameter oand one-way classification models, are given. We also present some simulations where the three corrected tests perform better than the usual score test, the likelihood ratio test and its Bartlett corrected version. Finally, we present a numerical example for a data set discussed by Simonoff and Tsai (1994) .     

基于最短路的配送中心选址决策与应用

物流作为“第三利润源泉”,对现代的经济活动影响日益明显,越来越引起人们的重视。配送是物流的核心问题,研究如何选择合理的配送中心和配送路线来降低配送运输成本,对物流总成本的节约具有十分重要的意义。论文从配送运输成本最小化目标出发,对单一配送中心选址以及一对一配送路线优化问题进行分析,并分别建立重心法选址模型和最短路算法模型,进行实例分析。     

公众期望与会计信息真实性的关联分析

公众对会计的期望与对会计行为的认识之间存在期望差距,基于不同期望水平对会计信息失真现象所作的分类揭示了会计信息真实性的内涵。通过公众期望与会计信息真实性的关联分析可以发现,加强公众与会计界的沟通理解以及强化会计信息失真的治理,是解决会计信息真实性问题的有效途径。     

Money, Sex and Happiness: An Empirical Study

The links between income, sexual behavior and reported happiness are studied using recent data on a sample of 16,000 adult Americans. The paper finds that sexual activity enters strongly positively in happiness equations. Higher income does not buy more sex or more sexual partners. Married people have more sex than those who are single, divorced, widowed or separated. The happiness‐maximizing number of sexual partners in the previous year is calculated to be 1. Highly educated females tend to have fewer sexual partners. Homosexuality has no statistically significant effect on happiness.     

Human Capital and Growth Cycles

This paper studies the dynamic interaction between human capital accumulation and economic growth. Capital market imperfections and an indivisibility in human capital investment prevent poor agents from accumulating skills, the acquisition of which positively affects technological progress. More productive technologies in turn require more sophisticated qualification and involve higher training costs. The equilibrium dynamics can be characterized by the joint evolution of productivity growth, the schooling costs, and the income distribution. Under our assumptions, individual incomes follow a non-linear Markov chain. This non-linearity generates endogenous fluctuations of schooling activities and the rate at which productivity improvements occur. We thank an anonymous referee for many helpful suggestions. Support from the German Research Foundation (DFG) under grant KA1519/2-2 is gratefully acknowledged.     

基于时间约束的多源多品种随机配送系统模型

在基于时间竞争的随机需求环境下,配送系统设计除了使系统总费用的期望值最小外,还要考虑系统稳定性和服务水平等方面的要求。在说明了建模的假设条件后,建立了考虑随机需求和时间约束的多源配送系统随机模型。通过等价变换,将随机模型转化为确定性等价问题,从而方便了问题的求解。     

考虑违约距离的上市公司危机预警模型研究

在上市公司财务危机预警中,违约距离起着重要的不可替代的作用,仅考虑财务指标并不足以完全解释企业财务危机发生的原因.文章应用Merton模型对2002～2004年ST公司和相应配对公司的危机发生之前的违约距离进行了研究,发现危机公司违约距离在危机发生前第三年明显低于正常公司的相应值,违约距离比传统财务指标能更早地预警到企业财务危机的发生.结合违约距离因素的危机预警模型能更明显地提高模型的危机判断正确率.     

Distributional aspects of the divisibility of money: an example

Summary. I highlight the importance of the distributional aspects of moneys divisibility by comparing a search-theoretic model with random transfers of indivisible money balances, to one with deterministic transfers of partially divisible balances. Randomization allows price flexibility, as if money were fully divisible. Partial divisibility does not, but allows money redistributions. An example of the relevance of such extensive margin aspects of divisibility is provided.JEL Classification Numbers: D30, D83, E40.I thank Dean Corbae and seminars participants at the Federal Reserve Bank of Richmond, University of Texas at Austin, Purdue University, the Midwest Macroeconomics Meetings, the Central Bank Institute of the Federal Reserve Bank of Cleveland, and the meetings of the Society for the Advancement of Economic Theory, where this work has been presented during the years 2002 and 2003.     

Bioenergy Crop Production in the United States: Potential Quantities, Land Use Changes, and Economic Impacts on the Agricultural Sector

The U.S. Departments of Agriculture and Energyjointly analyzed the economic potential for,and impacts of, large-scale bioenergy cropproduction in the United States. Anagricultural sector model (POLYSYS) wasmodified to include three potential bioenergycrops (switchgrass, hybrid poplar, and willow). At farmgate prices of US $2.44/GJ, anestimated 17 million hectares of bioenergycrops, annually yielding 171 million dry Mg ofbiomass, could potentially be produced at aprofit greater than existing agricultural usesfor the land. The estimate assumes highproductivity management practices are permittedon Conservation Reserve Program lands. Traditional crops prices are estimated toincrease 9 to 14 percent above baseline pricesand farm income increases annually by US $6.0billion above baseline.At farmgate prices of US $1.83/GJ, anestimated 7.9 million hectares of bioenergycrops, annually yielding 55 million dry Mg ofbiomass, could potentially be produced at aprofit greater than existing agricultural usesfor the land. The estimate assumes managementpractices intended to achieve highenvironmental benefits on Conservation ReserveProgram lands. Traditional crops prices areestimated to increase 4 to 9 percent abovebaseline prices and farm income increasesannually by US $2.8 billion above baseline.     

也谈价值、分配等问题--与程恩富、汪桂进两位先生商榷

现实中的价值分配与价值创造相关,主张价值分配与价值创造无关是不正确的;社会主义市场经济中劳动者的资本收入具有劳动收入的性质,以为资本创造价值或者资本收入是非劳收入是不正确的;现阶段的按要素分配只是分配的表现形式,其实质则是按劳分配。