Reasoning with contextual graphs - Leitura de Artigos

Reasoning with contextual graphs
Patrick Brezillon *, Laurent Pasquier, Jean-Charles Pomerol
Received 15 December 1999; accepted 15 October 2000

Abstract

... model highly contextual reasoning ... introduce the notion of contextual graph to take into account temporal and context-based reasoning. This model relies on observed reasoning modes in which the context and its dynamics are essential.

Introduction

[SART e incidentes de controle de tráfego]

... three types of context, namely, the external context, the contextual knowledge and the proceduralized context. These three types of context allow to model the various information needed at each step of the incident resolution.

[Divisão em três tipos: contexto do conhecimento (a ser usado para a tomada de decisão), contexto externo (parte não utilizada mas ainda assim necessária para contextualizar completamente a resposta) e contexto procedural (parte do contexto do conhecimento que está sendo usado em um ponto específico da tomada de decisão)]

Context and reasoning

... we defined contextual knowledge as the part of the context that is relevant in a given situation for a given operator .... This may be seen as the subset of the context in which the operator can find every chunk of knowledge for reasoning about or interpreting and explaining the situation. The complementary part in the context is called external context.

[Contexto do conhecimento é a parte do contexto que o usuário levará em consideração para avaliar a validade e a utilidade das afirmações contextualizadas recuperadas. Este contexto pode ou não ter sido especificado na consulta. Se não foi especificado e foi usado um contexto default, este será explícito na resposta. As outras dimensões contextuais seriam contexto externo. Mas a melhor resposta possível irá recuperar todo o contexto associado representado e explicitamente modelado no KG, independente de ser externo ou não.]

... the proceduralized context as the proceduralized part of the contextual knowledge, which is considered explicitly, with causal and consequential links, at a given step of the problem solving. Indeed, the operators do not consider at each moment all the contextual pieces of knowledge during an incident solving. The proceduralized context is the part of the contextual knowledge on which the operators are focusing on at a given step of the incident solving ...

[Parte do contexto do conhecimento. Contexto é composto de contexto do conhecimento e contexto externo e o contexto do conhecimento é subdividido em contexto procedural, ou seja, o que está sendo usado no momento para a tomada de decisão.]

Decision tree representation of the reasoning

In some cases, especially at the beginning of the tree, making decision under uncertainty is probably interesting, but by trying to gather relevant information the operators endeavor to make decision under certainty.

[A certeza aumenta a medida que se desloca para a folha da árvore]

Contextual graph representation of the reasoning

The contextual graph is intended to represent the part of the context that we have denoted proceduralized context, i.e., context chunks ready to be used for action.

[Este contexto é o da tarefa, da tomada de decisão]

The proceduralization of the contextual knowledge is a process that makes explicit the links, especially the causal and consequential links, between contextual knowledge chunks and as such the links become a part of the proceduralized context.

Validation and implementation

At the beginning, we tried to represent the operators' knowledge by decision trees, but a further study quickly shown that the problem was not really a problem of decision under uncertainty but a problem of diagnosing, as soon as possible, the real state of nature.

Conclusion