Monetary policy and economic performance, Summer 1976-November 1980 : an overview

An abstract for this article is not available.Monetary policy

Inside the Economist's Mind: The History of Modern Economic Thought, as Explained by Those Who Produced It

This is the front matter from a book of interviews to be published by Blackwell. The book is coedited by W. A. Barnett and P. A. Samuelson. The front matter includes the Table of Contents, Coeditor Preface by W. A. Barnett, Coeditor Foreword by Paul A. Samuelson, and History of Thought Introduction by E. Roy Weintraub. The front matter highlights some of the more startling and controversial statements contained in the interviews and puts the interviews into context relative to the history of modern economic thought. The interviews reprinted in this book include: (1) Wassily Leontief interviewed by Duncan Foley. (2) David Cass interviewed jointly by Steven Spear and Randall Wright. (3) Robert E. Lucas interviewed by Bennett T. McCallum. (4) Janos Kornai interviewed by Olivier Blanchard. (5) Franco Modigliani interviewed by William Barnett and Robert Solow. (6) Milton Friedman interviewed by John Taylor. (7) Paul A. Samuelson interviewed by William A. Barnett. (8) Paul Volcker interviewed by Perry Mehrling. (9) Martin Feldstein interviewed by James Poterba. (10) Christopher Sims interviewed by Lars Peter Hansen. (11) Robert Shiller interviewed by John Campbell. (12) Stanley Fischer interviewed by Olivier Blanchard. (13) Jacques Drèze interviewed by Pierre Dehez and Omar Licandro. (14) Tom Sargent interviewed by George Evans and Seppo Honkapohja. (15) Robert Aumann interviewed by Sergiu Hart. (16) James Tobin and Robert Shiller interviewed by David Colander.history of economic thought, Samuelson, macroeconomics, microeconomics, policy, interviews

On the Synthesis of Optimal Control Laws

In this paper we advocate for Isaacs\u27 method for the solution of differential games to be applied to the solution of optimal control problems. To make the argument, the vehicle employed is Pontryagin\u27s canonical optimal control example, which entails a double integrator plant. However, rather than controlling the state to the origin, we correctly require the end state to reach a terminal set that contains the origin in its interior. Indeed, in practice, it is required to control to a prescribed tolerance rather than reach a desired end state; achieving tight tolerances is expensive, and from a theoretical point of view, constraining the end state to a terminal manifold of co-dimension n-1 renders the optimal control problem well-posed. Thus, the correct solution of the optimal control problem is obtained. In this respect, two target sets are considered: a smooth circular target and a square target with corners; obviously, the size of the target sets can be shrunk to become very small. Closed-loop state-feedback control laws are developed which drive the double integrator plant from an arbitrary initial state to the target set in minimum time. This is accomplished using Isaacs\u27 method for the solution of differential games, which entails Dynamic Programming (DP), working backward from the Usable Part (UP) of the target set, as opposed to obtaining the optimal trajectories using the necessary conditions provided by Pontryagin\u27s Maximum Principle (PMP). Special attention is given to the critical UP of the target set in the process of obtaining the global solution of the optimal control problem at hand. In this paper, Isaacs\u27 method for the solution of differential games is applied to the solution of optimal control problems and the juxtaposition of the PMP and DP is undertaken

Determining Follower Aircraft's Optimal Trajectory in Relation to a Dynamic Formation Ring

The specific objective of this paper is to develop a tool that calculates the optimal trajectory of the follower aircraft as it completes a formation rejoin, and then maintains the formation position, defined as a ring of points, until a fixed final time. The tool is designed to produce optimal trajectories for a variety of initial conditions and leader trajectories. Triple integrator dynamics are used to model the follower aircraft in three dimensions. Control is applied directly to the rate of acceleration. Both the follower's and leader's velocities and accelerations are bounded, as dictated by the aircraft's performance envelope. Lastly, a path constraint is used to ensure the follower avoids the leader's jet wash region. This optimal control problem is solved through numerical analysis using the direct orthogonal collocation solver GPOPS-II. Two leader trajectories are investigated, including a descending spiral and continuous vertical loops. Additionally, a study of the effect of various initial guesses is performed. All trajectories displayed a direct capture of the formation position, however changes in solver initial conditions demonstrate various behaviors in how the follower maintains the formation position. The developed tool has proven adequate to support future research in crafting real-time controllers capable of determining near-optimal trajectories.Comment: 11 pages, 20 figures, 2 table

Közgazdasági tudományháborúk

Nem újdonság, hogy a közgazdaságtan elmélettörténetét a legtöbb közgazdász lenézi. Szinte évente rendeznek szakmai vitákat az eszmetörténet intézményi szerepéről; mi több, egy 2001-es konferencián a terület ingatag állapotát dokumentálták Észak-Amerikában és még veszélyeztetettebb helyzetét az Egyesült Királyságban és Ausztráliában (Weintraub 2002b). A Duke Egyetem kivételével Észak-Amerika egyetlen „elit” egyetemén sincs köz- gazdaságtan-elmélettörténetből nemhogy rendszeres kurzus, de még program sem (Gayer 2002)