In the 1980s and 1990s, Joyal and Street developed a graphical notation for various flavours of monoidal category using graphs drawn in the plane, commonly known as string diagrams. In particular, their work comprised a rigorous topological foundation of the notation. In 2007, Harmer, Hyland and Melliès gave a formal mathematical foundation for game semantics using a notions they called ⊸-schedules, ⊗-schedules and heaps. Schedules described interleavings of plays in games formed using ⊸ and ⊗, and heaps provided pointers used for backtracking. Their definitions were combinatorial in nature, but researchers often draw certain pictures when working in practice. In this thesis, we extend the framework of Joyal and Street to give a formal account of the graphical methods already informally employed by researchers in game semantics. We give a geometric formulation of ⊸-schedules and ⊗-schedules, and prove that the games they describe are isomorphic to those described in Harmer et al.’s terms, and also those given by a more general graphical representation of interleaving across games of multiple components. We further illustrate the value of the geometric methods by demonstrating that several proofs of key properties (such as that the composition of ⊸-schedules is associative) can be made straightforward, reflecting the geometry of the plane, and overstepping some of the cumbersome combinatorial detail of proofs in Harmer et al.’s terms. We further extend the framework of formal plane diagrams to account for the heaps and pointer structures used in the backtracking functors for O and P.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Risk management is a set of principles and pratices which aims to identify, analyse and treat events that could happen in the development of software projects with the objective of reducing surprises and increasing the success rate of the projects. Although collaboration is important to the execution of those tasks, there has been little attention to the interaction steps of dialogues, or argumentation, which occur when those participants develop risk management discussions. This work presents a new approach, based on the argumentation theory, to the development of collaborative tasks of risk management. With grounds on "dialogue games", this approach proposes a new communication protocol tailored to the risk management needs. In particular, this protocol is defined by its locution acts and combination rules between those locutions. This way, this protocol allows the structuring and controlling of risk discussions being developed by participants in a debate. Based on the proposed protocol, this work also presents a web system - Risk Discussion System (RD system) - built to present a collaborative environment for risk discussions. Since those discussions are structured by the dialogue game, the system is responsible for the organization and the recording of those risk discussion on a memory, allowing the analysis and reuse of those discussions on future ones. Aiming to evaluate the proposed approach, together with the protocol and the system presented, two experiments were conducted in this project. Results of those experiments present positive evidence for the acceptance and applicability of the approach in risk discussions, and the increment of the quality of information that is usually managed by other kinds of strategies for risk and project management. / O gerenciamento de riscos é um conjunto de princípios e práticas que visa identificar, analisar e tratar eventos que possam vir a acontecer no desenvolvimento de projetos de software com o intuito de reduzir as surpresas e aumentar as chances de sucesso de um projeto. Apesar de a colaboração ser importante para a execução dessas atividades, pouca atenção tem sido dada aos passos de interação de diálogo, ou argumentação, que ocorrem quando esses participantes realizam discussões de gerenciamento de riscos. Este trabalho apresenta uma nova abordagem, baseada na teoria da argumentação, para o desenvolvimento de tarefas colaborativas de gerenciamento de riscos. Com sua fundamentação em jogos de diálogo , esta abordagem propõe um novo protocolo de comunicação adaptado às necessidades do gerenciamento de riscos. Em particular, este protocolo é definido por atos de locução e regras de combinação entre estas locuções, assim permitindo estruturar e controlar discussões de riscos realizadas por participantes de um debate. Baseado no protocolo proposto, este trabalho apresenta um sistema web - Risk Discussion System (RD System) - construído para fornecer um ambiente colaborativo para discussões de risco. Uma vez que tais discussões de riscos estejam estruturadas, o sistema é responsável por organizar e registrar tais discussões de riscos em uma memória, possibilitando que elas sejam analisadas e reutilizadas em discussões de riscos futuras. Com o intuito de avaliar a abordagem proposta, bem como o protocolo e o sistema apresentados, dois experimentos foram realizados neste projeto. Resultados desses experimentos apresentam evidência positiva para a aceitação e a aplicabilidade da abordagem em discussões de riscos, assim como incremento de qualidade das informações normalmente gerenciadas por meio de outras estratégias de gerenciamento de riscos e projetos.