Regulation of Stochastic Fisheries: A Comparison of Alternative Methods in the Pacific Halibut Fishery

This article considers the relative merits of ad valorem taxation, season controls, and entry limitation as methods the government may use to deal with the externality problem in the Pacific halibut fishery. This is accomplished by simulating a stochastic dynamic program that uses parameters obtained from empirical analysis of this fishery. Although we find taxation to be the preferred regulatory instrument, the efficiency gains from regulation are minor when compared with the losses associated with the demand, output, and stock uncertainty in the fishery.Environmental Economics and Policy, Resource /Energy Economics and Policy, Risk and Uncertainty,

A System of Subroutines For Iteratively Reweighted Least Squares Computations

A description of a system of subroutines to compute solutions to the iteratively reweighted least squares problem is presented. The weights are determined from the data and linear fit and are computed as functions of the scaled residuals. Iteratively reweighted least squares is a part of robust statistics where "robustness" means relative insensitivity to moderate departures from assumptions. The software for iteratively reweighted least squares is cast as semi-portable Fortran code whose performance is unaffected (in the sense that performance will not be degraded) by the computer or operating-system environment in which it is used. An [ell sub1] start and an [ell sub2] start are provided. Eight weight functions, a numerical rank determination, convergence criterion, and a stem-and-leaf display are included.

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

A method of modelling a system consisting of a cylindrical coil with its axis perpendicular to a metal plate of finite thickness, and a simple electrical circuit for producing a transient current in the coil, is discussed in the context of using such a system for de-icing aircraft surfaces. A transmission line model of the coil and metal plate is developed as the heart of the system model. It is shown that this transmission model is central to calculation of the coil impedance, the coil current, the magnetic fields established on the surfaces of the metal plate, and the resultant total force between the coil and the plate. FORTRAN algorithms were developed for numerical calculation of each of these quantities, and the algorithms were applied to an experimental prototype system in which these quantities had been measured. Good agreement is seen to exist between the predicted and measured results

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured