采用边界元法研究槽形波导的色散特性

本文提出了用边界元法分析槽形波导的方法。推导出了有关表达式,并对一典型例子进行了研究,计算了其色散特性;得到的数据均与其它方法的结果相吻合。由于本文方法推导简单,计算省时,所以是研究此类问题的有效途径。     

振荡器非线性器件的特性对振荡解的影响的Volterra级数研究

本文应用Volterra级数分析非线性振荡器中非线性器件的特性对振荡稳态解的影响。     

Inheritance and inequality when wealth enters the utility function

The distribution of wealth and its dynamic development are analyzed within a non-overlapping generations model. All individuals have identical preferences and abilities. Wealth is represented by land, which is available in fixed aggregate supply. Utility depends on a perishable consumption good and—due to a bequest and/or a prestige motive—in addition on land owned. Two configurations can occur as long run equilbrium: equality and two class dichotomy. All Two Class Equilibria are unstable. The Equality Equilibrium is unstable if and only if land is sufficiently productive. In the case of instability there is a process towards maximal concentration of wealth.For helpful discussions I am indebted to G. Clemenz, S. Krasa, and M. Winkler.     

Overcoming the socialist aftereffects in East Europe

East Europe has inherited from the collapsed socialist systems a web of interlocking practices such as allocation mentality, bribery, dependism, and leveraged bonus, which will take many years to untangle before a free market system can effectively operate. Simplistic solutions will backfire. Reorganization must proceed with contextual knowledge of the interlocking patterns. A causal loop analysis is presented.     

The serial correlation structure for a random process with steps

Summary We derive the detailed correlation structure for the simple “staircase model”: a process where white noise is superimposed on a deterministic step function that has equal rises and equal treads. It turns out that this structure is an immediate generalisation of that for a linear trend (which, for discrete data, can be alternatively considered as a step function with equal rises and unit treads). We compare the structure obtained with that for a random walk, and those for a subset of other ARIMA(p, 1,q) models, and those of general ARIMA(p, d, q) processes withd>1.