The Cognitive Dimensions of Notations framework has been created to assist the designers of notational systems and information artifacts to evaluate their designs with respect to the impact that they will have on the users of those designs. The framework emphasizes the design choices available to such designers, including characterization of the user's activity, and the inevitable tradeoffs that will occur between potential design options. The resulting framework has been under development for over 10 years, and now has an active community of researchers devoted to it. This paper first introduces Cognitive Dimensions. It then summarizes the current activity, especially the results of a one-day workshop devoted to Cognitive Dimensions in December 2000, and reviews the ways in which it applies to the field of Cognitive Technology.

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Abstract. Rejecting the temptation to make up a list of necessary and sufficient conditions for diagrammatic and sentential systems, we present an important distinction which arises from sentential and diagrammatic features of systems. Importantly, the distinction we will explore in the paper lies at a meta-level. That is, we argue for a major difference in metatheory between diagrammatic and sentential systems, by showing the necessity of a more fine-grained syntax for a diagrammatic system than for a sentential system. Unlike with sentential systems, a diagrammatic system requires two levels of syntax—token and type. Token-syntax is about particular diagrams instantiated on some physical medium, and type-syntax provides a formal definition with which a concrete representation of a diagram must comply. While these two levels of syntax are closely related, the domains of type-syntax and token-syntax are distinct from each other. Euler diagrams are chosen as a case study to illustrate the following major points of the paper: (i) What kinds of diagrammatic features (as opposed to sentential features) require two different levels of syntax? (ii) What is the relation between these two levels of syntax? (iii) What is the advantage of having a two-tiered syntax? 1

Abstract: Domain-Specific Visual Modeling Languages should provide notations and abstractions that suitably support problem solving in well-defined application domains. From their user’s perspective, the language’s modeling primitives must be intuitive and expressive enough in capturing all intended aspects of domain conceptualizations. Over the years formal and explicit representations of domain conceptualizations have been developed as domain ontologies. In this paper, we show how the design of these languages can benefit from conceptual tools developed by the ontology engineering community. 1.

The study of systems of communication may be divided into three parts: syntax, semantics and pragmatics. Accounts of the embedding of text-based languages in the computational processes of reasoners and communicators are relatively well developed; with accounts available for a spectrum of languages which ranges from the highly formalised and constrained, such as formal logics, to the highly informal and unconstrained natural languages used in everyday conversations. Analogies between diagrams and such textual representations of information are quite revealing about both similarities and differences and can provide a useful starting point for exploring the issues in a theory of diagrammatic communication. This paper sketches out a theory of diagrammatic communication, based upon recent studies of the syntactic, semantic and pragmatic component issues which such a theory must accommodate. In the context of this theory an exploration is made of the issues involved in answering...

The effective control of attentional focus is an essential requirement in mental reasoning based on mental models and mental images, as well as in the interaction with external diagrams. In this paper, we argue for spatial organization principles common to various mental subsystems that entail a noncentralistic control of focus. We give a brief overview of mental spatial reasoning and present a review of psychological findings related to cognitive control. We review existing modeling approaches that realize control of focus in imagery, scene recognition, and mental animation. Based on these foundations, we identify basic spatial organizing principles that are shared by the diverse subsystems collaborating in mental spatial reasoning. We discuss the implications of these principles in the framework of a computational modeling approach and give an outline of the conception of control of focus in our computational architecture Casimir.

Diagrammatic specification, modelling and programming languages are increasingly prevalent in software engineering and, it is often claimed, provide natural representations which permit of intuitive reasoning. A desirable goal of software engineering is the rigorous justification of such reasoning, yet many formal accounts of diagrammatic languages confuse or destroy any natural reading of the diagrams. Hence they cannot be said to be intuitive. The answer, we feel, is to examine seriously the meaning and accuracy of the terms "natural" and "intuitive" in this context. This paper highlights, and illustrates by means of examples taken from industrial practice, an ongoing research theme of the authors. We take a deeper and more cognitively informed consideration of diagrams which leads us to a more natural formal underpinning that permits (i) the formal justification of informal intuitive arguments, without placing the onus of formality upon the engineer constructing the argument; and (i...

In previous work we presented a diagrammatic syntax for logic programming which clearly `resembles' the semantics of predicates as relations, i.e. sets of tuples in the Universe of Discourse. This paper shows diagrams as an alternative formal notation for pure logic programming which not only emphasizes some structural features of logical statements, but could also be useful to conduct visual inferences and to communicate them. This paper describes the current state of our research on a visual inference system for answering visually posed queries by means of diagram transformations. Although the transformations are shown by example we point to their correctness and formal character.

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This paper addresses a spatio-temporal configuration problem that consists of integrating a set of interdependent constraints. The problem’s scenario is set to a day at a trade fair during which meetings need be dynamically scheduled and assigned respective spatial locations on a map. For this type of configuration problem, mental problem solving is model-based, i.e. the problem is mentally solved by instantiation of constraints; where multiple instantiations are possible, typically only few get constructed. As a result, the performance of a corresponding planning assistance system does not only depend on its use of computational resources but also on the user’s cognitive effort required to understand the current state of the system and to guide the planning process. Corollary, cognitive processing models have to be integrated into the assistance system to allow for better predicting current cognitive efforts and reasoning preferences. We analyze the scenario with respect to modelbased problem solving strategies and propose first ideas towards an assistance system that presents itself through different media in a ubiquitous computing environment.