Application of Decomposition and Generic Instantiation

It is believed that reusability in formal development should reduce the time and cost of formal modelling within a production environment. Event-B is a formal method that allows modelling and refinement of systems. Generic instantiation and decomposition are techniques that simplify formal developments by reusing existing models and avoiding re-proofs. We apply these techniques in Event-B for the development of a metro system case study based on safety properties. This work aims to be give some guidelines of a practical way to develop large systems by instantiation of generic models and (shared event) decompose components into smaller sub-components

Event-B model decomposition

Two methods have been identified in the DEPLOY project for Event-B model decomposition: the shared variable decomposition (called A-style decomposition), and the shared event decomposition (or B-style decomposition). Both allow the decomposition of a (concrete) model into several independent sub-models which may then be refined separately. The purpose of this paper is to introduce the Event-B model decomposition, from theory (A-style vs. B-style, differences and similarities) to practice (decomposition plug-in of the Rodin [1] platform)

Shared Event Composition/Decomposition in Event-B

The construction of specifications is often a combination of smaller sub-components. Composition and decomposition are techniques that support reuse and allow us to formally combine sub-components through refinement steps while reusing their properties. Sub-components can result from a design or architectural goal and a refinement framework should allow further parallel development over the sub-components. We propose the definition of composition and decomposition in the Event-B formalism following a shared event approach where sub-components interact via synchronisation over shared events and shared states are not allow. We define the necessary proof obligations to ensure a valid composition or decomposition. We also show that shared event composition preserves refinement proofs for sub-components, that is, in order to maintain refinement of compositions, it is sufficient to prove refinement between corresponding subcomponents. A case study applying these two techniques is illustrated using Rodin, the Event-B toolset

Hybrid Petri net model of a traffic intersection in an urban network

Control in urban traffic networks constitutes an important and challenging research topic nowadays. In the literature, a lot of work can be found devoted to improving the performance of the traffic flow in such systems, by means of controlling the red-to-green switching times of traffic signals. Different techniques have been proposed and commercially implemented, ranging from heuristic methods to model-based optimization. However, given the complexity of the dynamics and the scale of urban traffic networks, there is still a lot of scope for improvement. In this work, a new hybrid model for the traffic behavior at an intersection is introduced. It captures important aspects of the flow dynamics in urban networks. It is shown how this model can be used in order to obtain control strategies that improve the flow of traffic at intersections, leading to the future possibility of controlling several connected intersections in a distributed way

Messianisme et image dialectique au cinéma

[Résumé] Messianisme et Image Dialectique au Cinéma Le caractère éminemment historique de l’image, où l’expérience historique se fait par des images qui sont à son tour chargées d’histoire nous amène à une vision messianique de l’image cinématographique de Guy Debord à Godard (Agamben, 1998). Ce cinéma s’oriente vers une révélation finale qu’est la Révolution, la transformation sociale. Glauber Rocha autre cinéaste de l’image dialectique, partage également cette perpective messianique, ses films sont révèlateurs à la fois de l’oscillation entre le marxisme existentiel, le messianisme vécu et la perte de la vision rédemptrice. On développera autour de ce théme, à l’aide de la sémiotique, quelques considérations sur la création des signes par le cinéma et à partir de la question de l’intelligibilité dialectique de l’homme chez Sartre, pour que l’agir de l’homme, sa praxis, s’inscrit dans un but, tenter ainsi de comprendre l’image dialectique. D’après Sartre, l’homme est créateur des signes qu’on ne peut saisir qu’à partir de la compréhension du « dépassement », car toute action humaine est chargée et de présent et d’avenir (Theodor Schwarz,1990). Quel est donc le statut de l’image dans la création de ce dépassement? L’image dialectique rend-il visible l’invisible Salut Révolutionaire? On mettra en examen le caractére messianique de l’image cinematographiqu

Southwest airlines Co.: consistency for the future

This Work Project consists of an Equity Research report of Southwest Airlines Co., forecasting the future company’s performance. Currently, the company is one of the market leaders and has a higher operating margin than the industry. However, the arising of low-cost and ultra-low-cost airlines will increase the industry’s price pressure. Moreover, the company will face operating costs management challenges in the future, mainly related to labor and fuel, which will affect its operating margin, enhancing the company’s concerns regarding increasing operational measures. Hence, it was issued a “Hold” recommendation, estimating a price target of $58.76, as of December 2020

“Every human action is anthropophagic”: Oswald's Cultural Anthropophagy and Theoretical Psychology

The Freudian theory and the era of acceleration announced by the Futurist Manifesto arrived in Brazil in 1899 and 1909, respectively. Afterwards the concrete reception of these two significant events became more than the symptomatic revelation of the shocks provoked by industrial modernity and its powerful undercurrent of anxieties. The poet, „clown“, writer and major figure of the Brazilian modernist avant-garde, Oswald de Andrade (1890-1954) absorbed Freud and the Futurist Manifesto at once, re-pragmatized and re-semantized them. Oswald's concept of Cultural Anthropophagy (1928) as a central interpretative strategy, to be exact, an hermeneutic approach is defined by Haroldo de Campos aptly: “Oswald's ‘Anthropophagy’ [...] is the thought of critical devoration of the universal cultural heritage” (Campos,1986). The introduction of the anthropophagic trope inspired by Native Americans’ metaphysics leads the poet to a subversion of the Gestalt/Behavior psychological theories: “The anthropophagic function of the psychological behavior is reduced to two parts: 1) totemiser the external taboos; 2) create a new taboo in exogamic function” (Andrade,1929). From 1928 to 1950 the Anthropophagy approach on the interaction between the individual and the environment gained philosophical consistency. Oswald's thesis is a conceptual alternative that attempted to bring answers through the amplification of our ethical becoming. As an epistemological perspective attentive to the different modes of existence, the proposition of Oswald is a field of transformative practices having the power to overcome the techno-industrial paradigms. I will examine the contribution of Oswald de Andrade to theoretical psychology and to the issues that arise in an “Era of Acceleration” where the symbolic field is replaced by a cybernetic field