Christoph Schlieder

Designing location-based mobile games with a purpose: collecting geospatial data with CityExplorer

The games with a purpose paradigm proposed by Luis von Ahn [9] is a new approach for game design where useful but boring tasks, like labeling a random image found in the web, are packed within a game to make them entertaining. But there are not only large numbers of internet users that can be used as voluntary data producers but legions of mobile device owners, too. In this paper we describe the design of a location-based mobile game with a purpose: CityExplorer. The purpose of this game is to produce geospatial data that is useful for non-gaming applications like a location-based service. From the analysis of four use case studies of CityExplorer we report that such a purposeful game is entertaining and can produce rich geospatial data collections.

Preferred and Alternative Mental Models in Spatial Reasoning

The mental model theory postulates that spatial reasoning relies on the construction, inspection, and the variation of mental models. Experiment 1 shows that in reasoning problems with multiple solutions, reasoners construct only a single model that is preferred over others. Experiment 2 shows that inferences conforming to these preferred mental models (PMM) are easier than inferences that are valid for alternatives. Experiments 3 and 4 support the idea that model variation consists of a model revision process. The process usually starts with the PMM and then constructs alternative models by local transformations. Models which are difficult to reach are more likely to be neglected than models which are only minor revisions of the PMM.

Qualitative Spatial Representation for Information Retrieval by Gazetteers

Intelligent and efficient information retrieval becomes increasingly important. Analogous to thesauri in the realm of spatial concepts, gazetteers offer a controlled vocabulary that can be used for spatial queries. Gazetteers use geographic footprints to link place names to geographic locations. Which geographic footprint representation is chosen has a strong impact on the quality of spatial queries. However, the footprint representations currently used in standard gazetteers such as points, lines, grid cell representations, and bounding boxes do not offer enough topological information to support refined spatial queries. We propose a new type of spatial footprint that can be described as a qualitative representation of the spatial decomposition of geographic entities. It holds enough topological and ordinal information enable refined spatial queries without being subject to the constraints of exact polygon representations. The proposed spatial representation was developed to be combined with terminological reasoning techniques used in systems for intelligent information integration.

Photographing a City: An Analysis of Place Concepts Based on Spatial Choices

Abstract We ask whether the photographs published in web-based image collections do represent different conceptualizations of a city and present a method for gathering and analyzing a data set of more than 12,000 images from Amsterdam, Bamberg, Cardiff, and Dublin. We then propose a measure for the popularity of a location in a city. The analysis of the data set reveals that the popularity follows a power law with very few highly popular locations and a long tail of places in a city that are visited only occasionally. The most popular locations can be identified with the semantic core of the conceptualization of the city in terms of images. This raises the issue of individual differences. We propose another measure that permits to identify users with similar conceptualizations of a city.

Winspect: a case study for wearable computing-supported inspection tasks

Introduces the Winspect project-an application of wearable computing in an industrial inspection process-with focus on its user interface. We present a case study to demonstrate the benefit of wearable input devices and the use of implicit interaction as a complementary technique. Two almost independent tasks from the application domain are addressed: the input of findings for inspected components in a harsh environment, and a technique to overcome the display resolution when browsing a hypertext-like documentation.

TeDUB: A System for Presenting and Exploring Technical Drawings for Blind People

Blind people can access and use textual information effectively in a variety of ways - through Braille, audiotape or computer-based systems. Access and use of graphic information is much more problematic, with tactile versions both time-consuming and difficult to make and textual descriptions failing to provide independent access to the material. The TeDUB Project is developing a system which will automatically generate descriptions of certain classes of graphics (electronic circuit diagrams, UML diagrams and architectural plans) and allow blind people to explore them independently. This system has great potential in work, education and leisure domains to open up independent access to graphic materials for blind people.

Pixel-Oriented Visualization of Change in Social Networks

We propose a new approach to visualize social networks. Most common network visualizations rely on graph drawing. While without doubt useful, graphs suffer from limitations like cluttering and important patterns may not be realized especially when networks change over time. Our approach adapts pixel-oriented visualization techniques to social networks as an addition to traditional graph visualizations. The visualization is exemplified using social networks based on corporate wikis.

The psychological validity of qualitative spatial reasoning in one dimension

One of the central questions of spatial reasoning research is whether the underlying processes are inherently visual, spatial, or logical. We applied the dual task interference paradigm to spatial reasoning problems in one dimension, using Allens interval calculus, in order to make progress towards resolving this argument. Our results indicate that spatial reasoning with interval relations is largely based on the construction and inspection of qualitative spatial representations, or mental models, while no evidence for logical proofs of derivations or the involvement of visual representations and processes was found.

Representing the meaning of spatial behavior by spatially grounded intentional systems

The problem of interpreting the trajectories of a person (user) moving in a spatial environment is fundamental for the design of any location-based application. We argue that in order to correctly assign a meaning to the spatial behavior encoded by the trajectory, it is necessary to express the meaning in terms of the users intentions, more specifically, the goals that the user intends to achieve. Along the trajectory, these intentions will change frequently because the users initial goal is decomposed into sequences of subgoals. The paper proposes a representational formalism and a reasoning mechanism for knowledge about an agent who acts according to changing intentions: spatially grounded intentional systems. An objective consists in making the representation as expressive as possible without running into a behavior interpretation problem that is computationally intractable. The approach is shown to be sufficiently expressive to model the interaction between intentions and behavior in a location-based game, CityPoker.

Intuitive Modelling of Place Name Regions for Spatial Information Retrieval

Reasoning about spatial relevance is important for intelligent spatial information retrieval. In heterogeneous and distributed systems like the Semantic Web, spatial reasoning has to be based on light-weight, interoperable and easy-to-use spatial metadata.