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Hysteresis is one of the main concepts used in Layard, Nickell and Jackman′s book, Unemployment: Macroeconomic Performance and the Labour Market. Attempts to clarify the concept of hysteresis, from its formal representation to its empirical applications. Emphasizes the idea that hysteresis refers back to a given set of formal properties, independently of the phenomenologies within which it is liable to be encountered. In economics, the fields concerned may indeed vary a lot (labour market, foreign trade, etc.). By highlighting all the formal properties of hysteresis, shows how the assimilation of phenomena characterized by a zero eigenvalue for linear systems (or unit‐root systems for discrete‐time processes) is wrong and, moreover, how the imprecise use of the concepts can lead to the particular constraints affecting unit‐root econometrics being overlooked.

The archives of François Perroux deposited at IMEC bear witness to the fact that he has devoted, beyond his scientific production, great energy to the most material aspects of research: setting up and maintaining networks to publicize his work and that of other economists, either directly or through the institutes and the journals he headed; organize seminars and symposiums; take care of relations with colleagues and the press; create collections and journals; and so on.

In this chapter, we concentrate our attention on the archives relating to the management of the institutes, those attesting to the lines and themes of the producer’s research, and those concerning his important correspondence.

Thanks to the archives deposited at IMEC, it is possible to follow the development of the theoretical work of François Perroux by contextualizing it. They also show the itinerary of a Christian intellectual, whose attachment to social Catholicism constitutes a guiding thread and is reflected in all his activities. Finally, the archives illuminate his substantial role in the institutionalization of research in economics in the France of the twentieth century.

Mean breaks in the Franco-German interest rate differential prior to European Monetary Union can have an economic interpretation, namely gains or losses in credibility of the corresponding ERM central exchange rate. A variety of tests are used to detect such breaks, on daily data covering the 1990s. The analysis paints a broadly consistent picture of these breaks and how expectations evolved before EMU. Results suggest that credibility was characterised by gains as well as setbacks; however an effective convergence is found from 1996 onwards, suggesting a major increase of the credibility of the French participation to EMU around that date.

A group of Computer Scientists recently asked for an explanation of the term text processing as it relates to work in Information Science. An interpretation of the term as used in the author's research was given and illustrated how that definition differed from the one usually applied in Computing, if not Computer Science.

The purpose of this paper is to present a method for determining the safe flight boundaries of the asymmetrically loaded airplane in the terminal flight phases. The method is applicable to both, the inherent airplane asymmetries and those asymmetries resulting from the airplane use irregularities, asymmetric stores under the wing being one of the examples. The method is aimed to be used in the airplane design and combat airplane service life support.

The analysis method is based on the comparison of demanded and structurally available flight control displacements. Control surface aerodynamic properties, structurally available flight control displacements and dynamic pressure define control surface authority as the capability of control surfaces to generate the forces and moments needed by the airplane to perform required maneuvers. Demanded flight control displacements are those related to the maneuvering requirements and to those needed to compensate lateral wind and any type of the asymmetric airplane load.

The method results are given in the form of the speed and lateral wind component and are a subset of the total set of airplane safe flight boundaries. The key objective is the improvement of flight safety of the asymmetrically loaded airplane.

The method supplements the safe flight boundaries of the symmetrically loaded airplane, the minimal landing speed being the dominant limitation. This boundary positions method analysis in the domain of linear lift coefficient variation, as the function of the angle of attack permits the addition of control surface displacements required to perform the maneuvers and compensate the asymmetrical loads.

The method combines a simple roll dynamics model, stationary equations of the airplane lateral-directional motion and several numeric analysis procedures to obtain the results. This new combination possesses synergy properties and is implemented as the computer program.

This paper compares the predictive power of linear econometric and non-linear computational models for forecasting the inflation rate in the European Monetary Union (EMU). Various models of both types are developed using different monetary and real activity indicators. They are compared according to a battery of parametric and non-parametric test statistics to measure their performance in one- and four-step ahead forecasts of quarterly data. Using genetic-neural fuzzy systems we find the computational approach superior to some degree and show how to combine both techniques successfully.