Luís A. Lima Silva

PetroGrapher: managing petrographic data and knowledge using an intelligent database application

This paper describes the PetroGrapher system, an intelligent database application to support petrographic analysis, interpretation of oil reservoir rocks, and management of relevant data using resources from both knowledge-based system technology and database technology. In this project, the visual tacit knowledge applied in petrographic analysis was rendered explicit through the collection of cases (rock descriptions), which were then used in the development of a domain ontology organized in a partonomy. Expert-level basic features, which we call ‘visual chunks’, were identified. The cases were further compared against the ontology to elucidate the relations between features in descriptions of rocks, visual chunks and expert interpretations. The domain knowledge was represented through a set of frames and knowledge graphs. The knowledge graphs are applied to recognize the visual chunks in the user data and retrieved the related interpretation. The system was developed as a structure tightly coupled with a relational database system, which acts as a repository for the knowledge base and the user data, and an object-oriented component, which preserves the semantics of data and develops inferences. The system was validated by three groups of users with different levels of expertise. q 2003 Elsevier Ltd. All rights reserved.

How to Model Visual Knowledge: A Study of Expertise in Oil-Reservoir Evaluation

This work presents a study of the nature of expertise in geology, which demands visual recognition methods to describe and interpret petroleum reservoir rocks. In an experiment using rock ima ges we noted and analyzed how geologists with distinct levels of expertise described them. The study demonstrated that experts develop a wide variety of representations and hierarchies, which differ from those found in the domain literature. They also reta in a large number of symbolic abstractions for images. These abstractions (which we call visual chunks) play an important role in guiding the inference process and integrating collections of tacit knowledge of the geological experts. We infer from our experience that the knowledge acquisition process in this domain should consider that inference and domain objects are parts of distinct ontologies. A special representation formalism, kgraphs+, is proposed as a tool to model the objects that support the infer ence and how they are related to the domain ontology.

Semi-Autonomous Navigation for Virtual Tactical Simulations in the Military Domain.

Integrated constructive and virtual simulations are becoming popular for tactical training in the military domain. An important aspect concerning the integration of these simulation models in the construction of virtual tactical simulations is the modelling and implementation of different kinds of semi-autonomous agents. A fundamental feature of these agents is the capability of intelligently and realistically modelling task-oriented navigation activities in large virtual terrain simulation environments, while following underlying military doctrine and tactics. This paper reviews important navigation issues that emerge in such simulation systems and prominent Artificial Intelligence (AI) techniques that have been explored to solve them. From this analysis, a hybrid, semi-autonomous navigation framework is proposed aiming to fulfil the needs of virtual tactical training simulations, more specifically, in the military domain. As implemented in a system for the virtual tactical simulation of artillery battery tasks, the framework shows how to overcome the challenges of implementing realistic global and local navigation behaviours for military units and, at the same time, it shows that the semi-autonomous behaviours implemented are of primary importance to allow interaction with users for learning purposes in the simulation exercises.

A Knowledge Engineering Process for the Development of Argumentation Schemes for Risk Management in Software Projects.

The engagement of project stakeholders in collaborative debates of risk management has an important contribution to software projects. To promote the identification, (re)use and critical analysis of stakeholders’ arguments in these debates, this paper lays out a knowledge engineering process for the development of “argumentation schemes” for risk management. This process covers activities of identification, interpretation and causal-and-effect analysis of typical risk statements. From such risk management information and reusing generalized argumentation templates from argumentation catalogues discussed in the field of Artificial Intelligence, the process leads to the specification, generalization, validation and indexing of the developed schemes. As implemented in our project, a web-based system to support the execution of these development activities allows the recording of these schemes in a semi-structured representation format. An argumentation scheme for risks of non-stable requirements is presented so as to show the reusable argumentation artifacts that can be produced when our development process is followed. Keywords-component: Risk Management; Argumentation Schemes; Argumentation.

Argumentation Schemes for the Collaborative Debate of Requirement Risks in Software Projects.

Managing risks in real-world software projects is of paramount importance. A significant class of such risks is related to the engineering of requirements, commonly involving the presentation and analysis of risk management arguments from both software engineers and clients involved in collaborative debates. In this work, drawing inspiration from argumentation theory in Artificial Intelligence, we introduce a number of “argumentation schemes” and associated “critical questions” to support such discussions. In doing so, we propose schemes related to risks due to excessive numbers of requirements; inadequate client representatives and poor understanding of client needs; incorrect, incomplete and conflicting requirements, and complex and non-traceable requirements. We also present a case study where the developed schemes were used to support the discussion of requirement risks in the context of a research and prototyping software project for the Brazilian Army. Keywords-component: Argumentation Schemes; Requirement Risks; Risk Management; Argumentation.

A task-oriented and parameterized (semi) autonomous navigation framework for the development of simulation systems

Abstract Agent behaviors in simulation systems are related to fundamental capabilities of realistically developing (semi) autonomous navigation actions. This is particularly important when dealing with the implementation of Computer Generated Forces (CGFs) for simulation systems in tactical military training applications. Moreover, these systems take into consideration the particularities of the domain-specific simulation tasks and the numerous heterogeneous CGFs inserted on them in order to generate better knowledge and learning experience to simulation system users. Based on these reasons, this paper reviews recurrent navigation problems as to propose a task-oriented and parameterized (semi) autonomous navigation framework to deal with CGF navigation needs in military simulation. Combining global and local navigation techniques, and controlled transition between alternative degrees of navigation autonomy, the framework aims to overcome the challenges of implementing customizable CGF navigation behaviors and, at the same time, to allow interaction with both users and other simulation systems in distributed simulation settings. A case study is presented in which the proposed techniques are analyzed in a domain-specific simulation problem providing evidence of their suitability to address the studied military simulation problems.

Argumentation Schemes for Collaborative Debate of Requirement Risks in Software Projects

Managing risks in real-world software projects is of paramount importance. A significant class of such risks is related to the engineering of requirements, commonly involving the presentation and analysis of risk management arguments from both software engineers and clients involved in collaborative debates. In this work, drawing inspiration from argumentation theory in Artificial Intelligence, we introduce a number of “argumentation schemes” and associated “critical questions” to support such discussions. In doing so, we propose schemes related to risks due to excessive numbers of requirements; inadequate client representatives and poor understanding of client needs; incorrect, incomplete and conflicting requirements; complex and non-traceable requirements; non-stable requirements; and low quality requirements. We also discuss a case study and two experiments where the developed schemes supported the discussion of requirement risks in software projects. The overall results of these experiments indicate t...

Uma Ontologia para Apoiar Discussões de Riscos em Projetos de Software

Um gerenciamento de riscos efetivo em projetos de software e importante para garantir que os fatores que podem impactar no sucesso e na qualidade de um sistema desenvolvido estao sob controle. Alem disso, melhorar a comunicacao entre participantes de um projeto, bem como integrar suas diferentes experiencias e perspectivas sobre este dominio de problema e imprescindivel. O objetivo deste trabalho e demonstrar como explorar a representacao de um dominio de conhecimento por meio de ontologias para suportar a identificacao e analise colaborativa de riscos em projetos de software. Para isso, a ontologia proposta foi criada para apoiar o desenvolvimento de atividades de gerenciamento de riscos tipicamente envolvidas nestas discussoes colaborativas de riscos.