March 16th, 2017

Today, the development costs of high confidence systems explode with their size. We are far away from the solution of the so-called, software crisis. In fact, the latter hides another much bigger: the system crisis. n my talk I will discuss rigorous system design as a formal and accountable process leading from requirements to correct-by-construction implementations. I will also discuss current limitations of the state of the art and advocate a coherent scientific foundation for system design based on four principles: 1) separation of concerns; 2) component-based construction; 3) semantic coherency; 4) correctness-by-construction. The combined application of these principles allows the definition of a methodology clearly identifying where human intervention and ingenuity are needed to resolve design choices, as well as activities that can be supported by tools to automate tedious and error-prone tasks. The presented view for rigorous system design has been amply implemented in the BIP (Behavior, Interaction, Priority) component framework and substantiated by numerous experimental results showing both its relevance and feasibility. I will conclude with a discussion advocating a system-centric vision for computing, and a deeper interaction and cross-fertilization with other more mature scientific disciplines

La "méthode Monnet", unification monétaire européenne et globalisation financière

17 p.L'objectif de cette étude est double. Le premier enjeu est de mener une analyse critique du modèle du "déséquilibre créateur" ("méthode Monnet") concernant la dynamique du projet d'unification monétaire européenne. Cette étude fait apparaître que l'unification monétaire européenne n'est pas le produit d'une dynamique institutionnelle initiée par la Commission et déclenchée par la réalisation des réformes de l'Acte unique. En fait, ce modèle a servi d'""alibi"" théorique d'une décision stratégique, reflet de compromis entre les deux états européens les plus puissants. Le second objectif de l'étude est de montrer que les réformes de l'Acte unique, et notamment la libéralisation complète des mouvements des capitaux, ont fortement contribué à l'intégration du continent européen au processus de globalisation financière. La libéralisation des mouvements de capitaux ne concernait pas seulement les résidents de l'Union européenne mais également le capital non-européen - sans que la réciprocité soit exigée - alors que seule la libéralisation des mouvements de capitaux européens était nécessaire pour la mise en place de l'espace financier européen, complément du Marché unique. C'est pour obtenir des concessions quant au projet d'unification monétaire qu'ils soutiennent activement, que certains pays (dont la France), acceptent la libéralisation complète des mouvements des capitaux à laquelle ils se sont jusqu'alors fermement opposés. Le revirement français et la perspective de tirer bénéfice des fonds structurels et régionaux mis en place par l'Acte unique contribuent à vaincre l'opposition manifestée jusqu'alors à cette mesure par des pays moins développés de l'Union

EU institutional framework and euro zone crisis

15 p.This paper explores the impact of Europe's existing institutional framework on the degree of macroeconomic disparity in the Eurozone. It draws son analysis of the costs of this framework as well as of the benefits of European economic and monetary unification. It also highlights how these costs and benefits are distributed geographically. There is a fundamental difference between the economic advantages of European economic and monetary unification, and the costs and risks associated with the system set up to promote unification. Many of the benefits of economic and monetary unification will only really be felt in the medium or even long term. In contrast the impact of the costs incurred by EMU operation is increasingly apparent - and more so as time passes - mainly penalizing the least developed European countries. The thrust of this study is that in its current form the EMU's institutional framework is not viable. It encourages the accumulation of lasting imbalances at the expense of Europe's least developed nations. While giving rise to substantial costs and risks for these countries, it jeopardizes the institutions and mechanisms which would enable them to cope. Imbalances associated with the operation of the EU give rise to negative externalities for the Union as a whole. The emergence of global finance - to which the Single European Act contributed - eveals and accentuates the Community's structural imbalance. To maintain consistent operation of the EMU, the burden of these costs and risks must be shouldered collectively through the coordination and centralization of economic policies and the development of budgetary federalism. But such conditions are extremely difficult to achieve and involve significant costs - some monetary, others not - that should be borne by the most prosperous European countries. These costs give rise to an uncooperative attitude, compromising the EMU as a viable system. One solution which me its consideration would be a reappraisal - on a negotiated and collectively approved basis - of certain aspects of Europe's existing institutional framework

L’influence de la taille sur l’endettement des entreprises industrielles grecques

Cet article analyse les résultats d’une étude empirique sur l’effet de la taille sur la structure financière des entreprises industrielles grecques. Il fait également une comparaison systématique des résultats obtenus avec ceux d’autres études réalisées sur le même thème en Grèce et à l’étranger. On démontre que la structure financière des entreprises industrielles grecques de grande taille présente certaines caractéristiques stables qui les différencient nettement des grandes entreprises de pays d’un niveau de développement supérieur. Ces caractéristiques sont les taux d’endettement très élevés, sensiblement plus élevés que ceux des entreprises des autres tailles, en particulier vis-à-vis des institutions de crédit. Les déterminants de ces particularités sont recherchés dans l’influence simultanée de deux facteurs : du caractère familial de la majorité d’entre elles et des structures bancaires. Le premier facteur influe au niveau de la structure financière des entreprises en augmentant le coût de financement par émission d’actions et en encourageant une politique de distribution de bénéfices. Les structures bancaires grecques déterminent des pratiques au niveau de la politique de crédit, qui encouragent le surendettement des entreprises de grande taille en diminuant le risque d’endettement.This article analyses results of an empirical study on the effect of size on financial structure of Greek industrial firms. It also makes systematical comparison of the obtained results with those of other studies on the same subject in Greece and abroad. It provides evidence that financial structure of large-sized Greek firms presents some stable characteristics which differenciate them from large firms in countries of superior level of development. These characteristics are the high debt ratios, considerably higher than those of firms of other sizes, in particular as regards financial institutions. The determinants of characteristics of the financial structure of large Greek firms have been saught in the simultaneous influence of two factors: the family-owned character of the majority of them and the banking structures. The former has an influence on the financial structure of firms by raising the cost of equity and by encouraging withdrawal of corporate funds and diversification towards other presumably less risky activities. The Greek banking structures, on the other hand, determine a credit policy which encourages the over-indebtedness of large-sized firms

Modelling Timeouts without Timelocks

We address the issue of modelling a simple timeout in timed automata. We argue that expression of the timeout in the UPPAAL timed automata model is unsatisfactory since when composed with a component behaviour, the timeout can generate timelocks. In response we consider an alternative timed automata framework - timed automata with deadlines. This framework has the property that timelocks cannot be created when composing automata in parallel. We explore a number of different options for reformulating the timeout in this framework and then we relate them

L’influence de la taille sur l’endettement des entreprises industrielles grecques

This article analyses results of an empirical study on the effect of size on financial structure of Greek industrial firms. It also makes systematical comparison of the obtained results with those of other studies on the same subject in Greece and abroad. It provides evidence that financial structure of large-sized Greek firms presents some stable characteristics which differenciate them from large firms in countries of superior level of development. These characteristics are the high debt ratios, considerably higher than those of firms of other sizes, in particular as regards financial institutions. The determinants of characteristics of the financial structure of large Greek firms have been saught in the simultaneous influence of two factors: the family-owned character of the majority of them and the banking structures. The former has an influence on the financial structure of firms by raising the cost of equity and by encouraging withdrawal of corporate funds and diversification towards other presumably less risky activities. The Greek banking structures, on the other hand, determine a credit policy which encourages the over-indebtedness of large-sized firms. Cet article analyse les résultats d’une étude empirique sur l’effet de la taille sur la structure financière des entreprises industrielles grecques. Il fait également une comparaison systématique des résultats obtenus avec ceux d’autres études réalisées sur le même thème en Grèce et à l’étranger. On démontre que la structure financière des entreprises industrielles grecques de grande taille présente certaines caractéristiques stables qui les différencient nettement des grandes entreprises de pays d’un niveau de développement supérieur. Ces caractéristiques sont les taux d’endettement très élevés, sensiblement plus élevés que ceux des entreprises des autres tailles, en particulier vis-à-vis des institutions de crédit. Les déterminants de ces particularités sont recherchés dans l’influence simultanée de deux facteurs : du caractère familial de la majorité d’entre elles et des structures bancaires. Le premier facteur influe au niveau de la structure financière des entreprises en augmentant le coût de financement par émission d’actions et en encourageant une politique de distribution de bénéfices. Les structures bancaires grecques déterminent des pratiques au niveau de la politique de crédit, qui encouragent le surendettement des entreprises de grande taille en diminuant le risque d’endettement.

Architecture Diagrams: A Graphical Language for Architecture Style Specification

Architecture styles characterise families of architectures sharing common characteristics. We have recently proposed configuration logics for architecture style specification. In this paper, we study a graphical notation to enhance readability and easiness of expression. We study simple architecture diagrams and a more expressive extension, interval architecture diagrams. For each type of diagrams, we present its semantics, a set of necessary and sufficient consistency conditions and a method that allows to characterise compositionally the specified architectures. We provide several examples illustrating the application of the results. We also present a polynomial-time algorithm for checking that a given architecture conforms to the architecture style specified by a diagram.Comment: In Proceedings ICE 2016, arXiv:1608.0313

Macroeconomic asymmetry and imbalances in the euro zone

15 p.The recent sovereign debt crisis in Europe, now a Eurozone crisis, has prompted a growing awareness of the disparities in the economic conditions and competitive positions of Eurozone countries. Such disparities are reflected in the accumulation of imbalances to the disadvantage of countries in Southern Europe, with the Eurozone tending to split into two groups, north and south. The present study explores the impact of Europe's existing institutional framework on the degree of macroeconomic disparity in the Eurozone. It draws on analysis of the costs and benefits of this framework, and how they are distributed geographically. There is a fundamental difference between the economic advantages of European economic and monetary union, and the costs and risks associated with the system set up to promote union. Many of the benefits of economic and monetary union will only really be felt in the medium or even long term. In contrast the impact of the costs incurred by EMU operation is increasingly apparent - and more so as time passes - mainly penalizing the least developed European countries. The thrust of this study is that in its current form the EMU's institutional framework is not viable. It encourages the accumulation of lasting imbalances at the expense of Europe's least developed nations. While giving rise to substantial costs and risks for these countries, it jeopardizes the institutions and mechanisms which would enable them to cope. An increasingly global market - to which the Treaty on the Single European Act contributed - reveals and accentuates the Community's structural imbalance. The growing imbalance fuelled by the way the Eurozone currently operates is undermining the EMU itself. It is also exacerbating tension between member states and the growing disaffection of public opinion with regard to the single currency. To maintain consistent operation of the EMU, the burden of these costs and risks must be shouldered collectively, through the coordination and centralization of economic policies and the development of budgetary federalism. But such conditions are extremely difficult to achieve and involve significant costs - some monetary, others not - borne by the most prosperous countries in the European Union. These costs give rise to an uncooperative attitude, compromising the EMU as a viable system. One solution which merits consideration would be a reappraisal - on a negotiated and collectively approved basis - of certain aspects of Europe's existing institutional framework