Elio Toppano

Functional and teleological knowledge in the multimodeling approach for reasoning about physical systems: a case study in diagnosis

The basic concepts of the multimodeling approach to the representation of physical systems are presented. Emphasis is placed on the exploitation of many, diverse models of a system for the execution of complex problem solving tasks, such as interpretation, diagnosis, design, simulation, etc. The considered models are based on different ontologies, representational assumptions, epistemological types, and aggregation levels. After a brief survey of the techniques adopted for representing structural and behavioral knowledge, attention is focused on function and teleology. A novel approach is proposed for defining, representing, and using these two types of knowledge which play a fundamental role both from the representation and reasoning perspectives. The fundamental claim is that while teleological knowledge concerns the specific purposes for which the system has been designed, functional knowledge is devoted to bridge the gap between such abstract purposes and the actual structure and behavior of the system, through the concepts of phenomena, processes, and functional roles. A clear definition is provided of all the various epistemological and ontological links existing between the different models. >

PUTTING FUNCTIONAL KNOWLEDGE ON FIRMER GROUND

Abstract In this paper we focus on the concept and representation of function in the context of the multi-modeling approach. The main contribution of the paper is to discuss the nature of functional knowledge and to disambiguate this type of knowledge from other types, such as teleology, behavior, and structure. Moreover, a general and theoretically sound framework for integration of these types of knowledge into a coherent system is proposed. Existing approaches to the definition and the representation of function are compared and their major limitations are highlighted. The concept of function and its representation in the multimodeling approach are illustrated. An example of functional representation concerning a household electric buzzer is discussed and the relations between functional knowledge and teleological, behavioral and structural knowledge are presented. The main contributions of our approach in the domain of diagnostic reasoning are summarized, and the paper concludes by mentioning current ...

Ontology engineering: reuse and integration

Reuse and integration are major steps in the ontology development process, often unavoidable to lower the costs of a new application. We address the two issues with an engineering approach, and provide a comprehensive account of the state of the art. The domain of e-learning is chosen as a test-bed to verify the feasibility of methods. Reuse and integration are shown to be effective in constructing domain representations with larger coverage and enhanced reasoning capabilities, which significantly extend the expressiveness of semantic software. Problems emerge from the lack of explicit representations of the assumptions taken: when reusing an ontology, one implicitly commits to the underlying context. We conclude that a new methodology should be put forward that views the development as a collaborative work within a community of stakeholders.

Representation and Use of Teleological Knowledge in the Multi-Modeling Approach

Artifacts are intentionally designed to serve some purpose. These purposes provide important information for understanding and reasoning about their behavior. The teleological analysis of an artifact is aimed at identifying the purposes associated to it by the designer and at explicitly representing their organization. Although teleological knowledge plays a fundamental role in understanding and reasoning about physical systems, the problem of how to represent and use it for activities such as diagnosis, design, simulation, etc. has been faced so far only in a partial and inadequate way. Past work on Qualitative Physics has mostly focused on how the behavior of a system can be derived from its structure using first principles (Bobrow, 1984); therefore, it does not deal with teleology. An exception is represented by the teleological analysis proposed by De Kleer (1984) within the electrical domain. More recently, Downing (1990) has investigated the role of teleological knowledge for the evaluation and explanation of physiological systems in satisfying purposes such as oxygen transport, carbon-dioxide dissipation, and heat conservation in diverse environments. Finally, some attention has been devoted to teleology by researchers focusing on functional representations. Sembugamoorthy and Chandrasekaran (1986), for example, propose a functional representation which is based on the assumption that understanding how a device works can be achieved by showing how an intended function is accomplished through a series of behavioral states. Keuneke (1989) enhances this functional representation including the specification of a taxonomy of function types, or purposes, such as: achieving a state, maintaining a state, preventing an undesirable state, and controlling state change.

Rational model selection in large engineering knowledge bases

It is generally admitted that several models differing along various dimensions are needed for executing complex engineering tasks such as diagnosis and monitoring. A key problem is thus to decide what model to use in a particular situation in front of a specified problem-solving task and reasoning objectives. We address this problem within the Multimodeling framework for reasoning about physical systems that we proposed in a previous work. After having characterized the space of possible models in the Multimodeling approach, we formulate the selection problem using the conceptual tools offered by the economic theory of rationality. In this frame we illustrate a preference-based model selection method that is used to navigate in the universe of available models of a system searching for the model that best matches a given task and reasoning objectives. The method exploits the use of a model map that is a metalevel concept representing the ontology and teleology of each model and the transformational relat...

Semiotic Design of a Hypermedia for Cultural Heritage

The paper proposes a semiotic model inspired to the narrative, structural framework by A.J.Greimas, and applied to the design and analysis of a hypermedia. The framework is structured into four levels of signification and allows for a constructive process of semantic aggregation. We follow such a process in order to explore the conceptual organization of the model. We construct a hypermedia regarding a collection of ancient mosaics from a roman villa. Our results indicate that the proposed approach opens novel perspectives, and looks promising towards the definition of semiotic methodologies of hypermedia design.

Prototype-based Conceptual Design: The SECS System

The paper investigates the problem of design synthesis with prototypes i.e., exemplary solutions in a given field which are obtained by generalization from a set of specific design cases. A framework for organizing prototypical knowledge using multiple models at different abstraction and generalization levels is described. Design synthesis with prototypes is modelled as a recoursive cycle consisting of recalling relevant prototypes, selecting most promising ones and adapting them to current situation. The approach is experimented using SECS a prototype-based system developed for supporting electronic engineers in the high level task of conceptual design of electronic circuits.

Semiotic design and analysis of hypermedia

The paper proposes a semiotic framework inspired to the Generative Trajectory of Meaning by A.J. Greimas to the design and analysis of hypermedia. The framework is structured into four levels of signification and allows the designer to control the semantic coherence and optimize the communication during the hypermedia development. We investigate its practical feasibility by constructing an instructional hypermedia regarding a collection of ancient mosaics from a roman villa. Our results indicate that the proposed approach opens novel perspectives, and looks promising towards the definition of semiotic methodologies of hypermedia design.

Semiotic-based Conceptual Modelling of Hypermedia

We address the conceptual modelling of hypermedia regarded as semiotic texts, whose meanings are conceived by a designer, transferred through the artifact and interpreted by users within their context. We outline the communication framework, with the artifact embedding the images of the designer and user. The full model is represented in terms of four interrelated modules: story, discourse, text and social-relational ontologies. The first and second one account for the narrative structures underlying the hypermedia content, which is externalized through sensorial qualities that, in turn, evoke impressions into the user. The model addresses issues that are poorly covered by the description standard MPEG-7. It can be used for analysis, evaluation, indexing of existing hypermedia as well as the design of new ones.

MM for TED: A Cognitive Tool Fostering the Acquisition of Conceptual Knowledge about Design Products.

The work described in this paper deals with conceptual understanding of design products. A working hypothesis is that the comprehension of something by someone is strongly related to the capability of the subject to build and use multiple representations of the thing under consideration and to explicitly consider their characteristics and their reciprocal dependencies in explanation and problem solving. A cognitive tool called MMforTED has been developed to foster the acquisition of several conceptualisations (ontologies) that can be used to represent and inquiry about artefacts from different perspectives. The system exploits an instructional environment implemented by an electronic hypertext, that enables users to browse through a network of models of several devices. Browsing through the network of models is accompanied by a simultaneous change of perspective. Because of the particular organisation of domain knowledge we have adopted, this amounts to exercising a well defined knowledge transmutation (e.g. conceptual abstraction, generalisation, reduction, approximation and aggregation or their inverses). The ability to explore a situation from different conceptual perspectives is considered fundamental for problem setting and design development.