Björn Gottfried

Reasoning about intervals in two dimensions

Qualitative reasoning approaches take on the challenge of dealing with commonsense knowledge in machines. This is important both to provide a means of efficient automatic reasoning and to overcome the differences between man and machine. This paper proposes a new qualitative representation of spatial knowledge based on interval relations. The representation complements existing approaches by providing a new set of spatial relations. This allows qualitative reasoning about rigid objects, for example, in spatial configuration problems or in the context of spatio-temporal interactions between objects. The qualitative nature of this representation assists the engineering process and makes the behaviour of systems more easily comprehensible.

Behaviour Monitoring and Interpretation

Behaviour Monitoring and Interpretation is a new field that developed gradually and inconspicuously over the last decades. With technological advances made at the sensory level and the introduction of ubiquitous computing technologies in the nineties this field has been pushed to a new level. A common methodology of many different research projects and applications can be identified. This methodology is outlined as a framework in this paper and supported by recent work. As a result it shows how BMI automates ethology. Moreover, by bringing in sophisticated AI techniques, it shows how BMI replaces a simple behaviour-interpretation mapping through computational levels between observed behaviours and their interpretations. This is similar to the way of how functionalism and cognitive sciences enabled new explanation models and provided an alternative approach to behaviourism in the early days of AI. First research results can be finally given which back up the usefulness of BMI.

Tripartite Line Tracks: Qualitative Curvature Information

We present a qualitative shape description which has previously been proven to be useful for object categorisation. The description is based on a set of shape primitives which we will restrict to a new subset of relations representing stylised curvature information. In contrast to other qualitative shape theories, this description enables us to distinguish different convex shapes. This is especially interesting from a cognitive point of view since these shapes show salient visual differences. It turns out that the distinction between two sides of a line together with the distinction between acute and obtuse angles make up a powerful concept of orientation information for shapes in two dimensions.

Qualitative similarity measures-The case of two-dimensional outlines

In this paper qualitative similarity measures are introduced. Depending on the underlying representation such similarity measures are based on specific qualitative distinctions which are frequently motivated by perceptual clear distinctions. Here, we discuss one such representation and show how it applies to different domains. In particular, qualitative methods are useful as soon as specific qualitative features can be defined for the purpose of characterising specific objects. Accordingly, we set two examples, namely for a domain of historical objects and for the geographic domain. Afterwards, however, we also demonstrate that our qualitative representation performs quite well when applied to a well-known test data set, without specifying any specific features. Instead, frequencies of qualitative relations are taken into account. The results indicate that qualitative measures not only relate to distinctions which can be easily comprehended by vision but that they are especially efficient in terms of runtime complexity, both issues being of particular importance in the case of image databases.

Representing short-term observations of moving objects by a simple visual language

In a variety of dynamical systems, formations of motion patterns occur. Observing colonies of animals, for instance, for the scientist it is not only of interest which kinds of formations these animals show, but also how they altogether move around. In order to analyse motion patterns for the purpose of making predictions, to describe the behaviour of systems, or to index databases of moving objects, methods are required for dealing with them. This becomes increasingly important since a number of technologies have been devised which allow objects precisely to get traced. However, the indeterminacy of spatial information in real world environments also requires techniques to approximate reasoning, for example, in order to compensate for small and unimportant distinctions which are due to noisy measurements. As a consequence, precise as well as coarse motion patterns have to be dealt with. A set of 16 atomic motion patterns is proposed. On the one hand, a relation algebra is defined on them. On the other hand, these 16 relations form the basis of a visual language using which motion patterns can easily be dealt with in a diagrammatic way. The relations are coarse but crisp and they allow imprecise knowledge about motion patterns to be dealt with, while their diagrammatic realisation also allow precise patterns to get handled. While almost all approaches consider motion patterns along arbitrary time intervals, this paper in particular focuses on short-term motion patterns as we permanently observe them in our everyday life. The bottom line of the current work, however, is yet more general. While it has been widely argued that it makes sense to use both sentential and diagrammatic representations in order to represent different things in the same system adequately (and hence differently), we argue that it makes even sense to represent the same things differently in order to grasp different aspects of one and the same object of interest from different viewpoints. We demonstrate this by providing both a sentential and a diagrammatic representation for the purpose of grasping different aspects of motion patterns. It shows that both representations complement each other.

Interpreting motion events of pairs of moving objects

When accumulating large quantities of positional data with ubiquitous positioning techniques, methods are required that can efficiently make use of these data. This work proposes a representation that approximates motion events of pairs of objects. It is shown how the employment of formal grammars enables the interpretation of such motion events. This is accomplished by composing motion patterns into specific qualitative features. In particular, the change of relative directions defines characteristic motion events.

Representing Spatial Activities by Spatially Contextualised Motion Patterns

The interpretation of spatial activities plays a fundamental role in several areas, ranging from the analysis of animal behaviour to location-based assistance applications. One important aspect when interpreting spatial activities consists in relating them to their environment. A problem arises insofar propositional representations lack an appropriate attention mechanism to comprehend the spatiotemporal development of spatial activities. Therefore, we propose a diagrammatic formalism which allows spatial activities to get classified depending on their spatial context and provide a link to propositional formalisms. It shows that RoboCup soccer is particularly suitable for investigating these issues. In fact, alone the spatial activity of the ball teaches us to a considerable degree much about a game.

Accessing Libraries of Media Art through Metadata

Being faced with digital libraries containing images and video content, means are required that characterize the content for efficient access. In addition, the confluence of media content which is distributed over a number of content providers requires a common and standardized way for searching the content. The usual solution consists in the employment of metadata which describes media content. Among others, issues that arise concern the kind of metadata to be used, how it is to be represented, and how it is to be integrated into the architecture of a portal for accessing the distributed digital archives. The methods presented in this paper have been implemented in the context of the project Gateway to Archives of Media Art (GAMA for short). The objective of this project is to establish a portal for online access to some of the most important digital archives and libraries on media art in Europe.

Set space diagrams

This paper introduces set space diagrams and defines their formal syntax and semantics. Conventional region based diagrams, like Euler circles and Venn diagrams, represent sets and their intersections by means of overlapping regions. By contrast, set space diagrams provide a certain layout that avoids overlapping geometrical entities. This enables the representation of a good deal of sets without getting diagrams which are cluttered due to overlapping regions. In particular, these diagrams can be employed for illustration purposes, e.g., for showing the laws of Boolean algebras. Additionally, cardinalities are represented and can be easily compared; inferences can be drawn to derive unknown cardinalities from a given knowledge base. The soundness of set space diagrams is shown with respect to their set-theoretic interpretation.

Spatial Health Systems

In this paper it is suggested to draw a dichotomy among health applications: on the one hand there are health information systems which provide means for dealing with health information, on the other hand there are spatial health applications which provide technical support for the elderly and disabled people. While the former enables health organisations to interchange information and provide patients information about health care, the latter directly supports patients in managing their everyday life. Discussing issues about spatial health applications from the computational point of view a problem is identified. Being grounded on measurements of the spatiotemporal change Of objects and especially of people, i. e. their locomotion, spatial health applications are in need of formalisms which are capable of dealing with imprecise spatial information. A computational framework shows how imprecise spatial information can be dealt with so that the locomotion problem gets tractable. Moreover, this framework aids in analysing and designing spatial health applications.