DYNAMIC SUPPLY FROM COMMON PROPERTY RESOURCE: WATER DIVERSIONS FROM THE GREAT LAKES

For many purposes, the five Great Lakes can be classified as an open access resource since there is no well-defined system of property rights governing these water uses in the lakes. Yet the Great Lakes Charter and the Water Resources Act of 1966 establish regulations concerning the diversion of water out of the basin. Thus, for interbasin water diversions the Great Lakes is more like a common property resource with rules governing such transfers. Moreover, water diversion decisions are interconnected since withdrawing water from one point may affect water levels in the entire lake system. This, in turn, can adversely affect hydropower production and commercial navigation. Contributing to the complexity of the problem are the eight U.S. states, two Canadian provinces and two federal governments which are involved in Great Lakes management. Game theory is used to describe this situation. Several games are constructed to describe different market structures. Of particular interest is the number of players who participate in the game, as well as the expectations they hold. Open-loop (where players commit themselves to future actions) and closed-loop (where players do not commit themselves to future actions) are compared for the ten players game (eight states and two provinces), two players game (U.S. and Canada) and one player game (a social planner's solution). The open-loop game is shown to ignore part of the externalities involved, and thus can underestimate the social loss caused by diversions from the lakes.     

NONMALLEABLE CAPITAL AND EFFICIENT ALLOCATION OF A NONRENEWABLE RESOURCE

Using a discrete-time model with nonmallable and durable capital embodied in a two-period recovery profile, we determine the efficient allocation of a nonrenewable resource and compare it with the corresponding Hotelling allocation for which capital is malleable. Depending on the recovery profile, efficient prices can rise strictly monotonically over time, rise in a stairwise fashion or rise in a sawtooth fashion around a rising price trend. Except for the sawtooth rise, this price behavior requires faster exhaustion than when capital is malleable, implying that the nonmalleability and durability of capital should not be ignored in nonrenewable resource models.     

LAND DEVELOPMENT AND WILDERNESS CONSERVATION POLICIES UNDER UNCERTAINTY: A SYNTHESIS

The effects of uncertainty and irreversibility on land management are examined in an infinite horizon Arrow-Fisher-Henry conservation model with non-linear land-use welfare function which accounts for the possible role of breakthrough benefits stemming from the genetic resources of wilderness. The effects of uncertainty on optimality and certainty-equivalent development strategies are examined. Crucially, “jump” decision rules are shown to be generally non-optimal for managing wilderness areas.     

Dynamic models relating processing parameters and melt track width during laser marking of clay tiles

This paper describes two dynamic models relating processing parameters and melt pool width during laser marking/engraving of clay tiles using a high-power diode laser. The models were determined by process identification techniques and were validated with a PI algorithm. The output variable considered for the laser clay tile marking process was melt pool width, measured by using a fast CCD recording system and analysed with an image-processing software. The input quantities investigated were laser power and traverse speed. Reasonable agreements between the measured data and the model outputs were achieved. Errors less than 1.3 μm of the melt pool width for the operating points were found. On the basis of these models a simple PI-controller was designed and tuned to guarantee zero steady-state error in case of an absorptivity disturbance.     

度量空间中反交换映射的公共不动点

本文讨论了度量空间中映射在反交换条件下的公共不动点的存在性问题,给出了映射对在满足一定条件时公共不动点的存在性与唯一性结论.并指出了文献[5]中的几处错误.     

Banach空间有限个极大单调算子公共零点的迭代注记

令E为实光滑、一致凸Banach空间,E*为其对偶空间.令AiE×E*,i=1,2,…,m,为极大单调算子且∩mi=1Ai-10≠φ.将给出一种计算量较小的新迭代算法,并利用Lyapunov泛函与广义投影算子等技巧,证明迭代序列弱收敛于A的公共零点,i=1,2,…,m.     

Cycles of fear: Periodic bloodsucking rates for vampires

In this paper, we present a new approach for modelling the dynamic intertemporal confrontation between vampires and humans. It is assumed that the change of the vampiristic consumption rate induces costs and that the vampire community also derives some utility from possessing humans and not only from consuming them. Using the Hopf bifurcation theorem, it can be shown that cyclical bloodsucking strategies are optimal. These results are in accordance with empirical evidence.     

Feedback Nash equilibria in a problem of optimal fishery management

The paper deals with a problem of optimal management of a common-property fishery, modelled as a two-player differential game. Under nonclassical assumptions on harvest rates and utilities, a feedback Nash equilibrium is determined, using a bionomic equilibrium concept. Later on, this assumption is relaxed and a feedback Nash equilibrium is established under minimal hypotheses.     

和田河流域资源开发利用与可持续发展

主要分析了田河流域的水，土资源概况及存在的问题，在研究流域人口，经济，资源，环境诸因素之间相互关系的基础上，用系统动力学模型动态定量模拟了流域人口，资源和经济发展的规模，并为流域今后的可持续发展提供了原则与对策。     

Inadmissibility of the uncombined two-stage estimator when additional samples are available

Consider the problem of constructing an estimator with a preassigned bound on the risk for a mean of a normal distribution. The paper shows that the usual two-stage estimator is improved on by combined estimators when additional samples taken from distributions with the same mean and different variances are available.