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Dr.-Ing. Christoph Stahl
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Address:
Saarland University
Building E 1 1
, Room 1.06
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Since 2011, I am managing research activities in the BAALL living lab at the DFKI Bremen / Safe and Secure Cognitive Systems group, i.e. european projects in the scope of FP7, EIT, and AAL Joint Programme.
In 2010, my job was to develop an in-car demonstrator for the M2CI Cluster of Excellence that integrated components from several projects, including multimodal interaction with the car's comfort systems and a driving simulator with front projection. In 2009, I have received a Dr.-Ing. from Saarland Unviersity for my thesis on the topic of spatial modeling of activity and user assistance in instrumented environments. My work describes the GOAL methodology for the design and development of assistance systems that integrate support for multiple activities and make intelligent use of ubicomp technologies and environments. Another result has been the Yamamoto toolkit that allows to model indoor environments with multiple levels and stairs and includes a route finding component. My previous work in the RENA project has been focused on pedestrian assistance in intelligent environments. For example, consider the combination of shopping and navigation tasks in an airport scenario. In the former project REAL, we have investigated how a system can assist its user in solving different tasks in an instrumented environment. The idea is to observe and recognize implicit user interaction and to let assistance applications infer about a user‘s plans and intentions and to proactively present situated information, adapted to user and context. I have designed and set up the overall architecture of our SUPIE environment, and participated in the development of its infrastructure, such as the positioning service, presentation service and navigation assistance. Previously, in the second period of REAL, I have implemented the automatic generation of graphical route descriptions for mobile devices in the indoor navigation system IRREAL. I have also developed the hybrid indoor- and outdoor navigation system COREAL, which has been exhibited at the CeBIT fair in 2002. At the DFKI (Deutsches Forschungszentrum für Künstliche Intelligenz), I have been working as a researcher in industry projects with Deutsche Telekom Innovation Center and BMW (BMW Personal Navigator). I have also been teaching student seminars on Ambient Intelligence, Location-Based Services and Intelligent User Interfaces at Saarland University. Please visit my personal homepage for more details on my projects, and you will also find my CV there. In 2007 I have co-organized a workshop on modelling and designing user assistance in intelligent environments (MODIE). Reviewing activity: IE05, MODIE Workshop 2006, MobileHCI 2008, CHI 2009, MobileHCI 2009, HSI09, HSI10, TEI'10, IPIN 2010, TEI'11, TSMPAD Workshop, MobileHCI 2011/2012, AAL Kongress 2012 PC Member: 2nd Workshop on Spatial Awareness and Geographic Knowledge Acquisition with Small Mobile Devices (You Are Here 2), 3rd Int. Workshop on Web Intelligence & Communities (WI&C'11, WI&C'12), TSMPAD Workshop If you'd like to take a tour in a venetian gondola near Munich, please visit my father's website :) |
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Projects |
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- RENA 2005-01-01 – 2007-12-31
- REAL-p2 1999-01-01 – 2001-12-31
- REAL-p3 2002-01-01 – 2004-12-31
- UbisWorld 2001-01-31 – 2011-01-31
Publications |
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2011
Synchronized Realities
Christoph Stahl, Jochen Frey, Jan Alexandersson, Boris Brandherm
Journal of Ambient Intelligence and Smart Environments, Vol. 3, Nr. 1/2011, pp. 13-25, IOS Press.
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Ambient Intelligence (AmI) promises future environments that support the well-being of their inhabitants through comfort and assistive environments. For the elderly users, Ambient Assisted Living (AAL) scenarios are targeting safe and independent living at home. Especially the integration of home automation components, such as intelligent light, window, and climate controls seem promising for such scenarios. In this paper, we present a new development method that is based on a detailed three-dimensional model and show how the model can be used for designing and evaluating assistive environments. Such a system has been developed and deployed. We present an architectural foundation of how Universal Remote Console technology can be applied to synchronize the virtual environment model with the real world. Furthermore, we extend previous work on Dual Reality by introducing the concept of Synchronized Realities that includes the synchronization between remote AmI environments. We will discuss application scenarios and show two demonstrators that we have implemented based on the proposed development method.
2010
The DFKI Competence Center for Ambient Assisted Living
Jochen Frey, Christoph Stahl, Thomas Röfer, Bernd Krieg-Brückner, and Jan
Alexandersson
Ambient Intelligence 2010
show abstract
The DFKI Competence Center for Ambient Assisted Living
(CCAAL) is a cross-project and cross-department virtual organization
within the German Research Center for Artificial Intelligence coordinating
and conducting research and development in the area of Ambient
Assisted Living (AAL). Our demonstrators range from multimodal
speech dialog systems to fully instrumented environments allowing the
development of intelligent assistant systems, for instance an autonomous
wheelchair, or the recognition and processing of everyday activities in a
smart home. These innovative technologies are then tested, evaluated,
and demonstrated in DFKI’s living labs.
UbiSpot – A User Trained Always Best Positioned Engine for Mobile Phones
Tim Schwartz, Christoph Stahl, Christian Müller, Hao Ji, Valentin Dimitrov
Proceedings of Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS 2010), IEEE, ISBN 978-1-4244-7878-1
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We implemented a positioning engine for mobile phones that can be trained by the users to recognize places as personal landmarks by their wireless communication fingerprint. Our always-best-positioned approach integrates heterogeneous sensor data, such as Bluetooth (BT) device addresses, WLAN MACs, GSM cell ids and GPS coordinates, if available. As an alternative to measuring the signal strength of wireless access points, our positioning engine measures the relative frequency of their appearance and disappearance over time, which closely correlates to their distance. The user can add new places as symbolic names to a hierarchical location model at any time using their mobile phone. For each place, the wireless sensor fingerprint can be trained by the user to define a landmark. Once landmarks have been trained, the positioning engine continuously matches the current sensor profile against the database of learned fingerprints and chooses the most likely place. In case that no BT or WLAN APs are visible, the hierarchical data model can at least derive a higher-level description of the current region based on GSM or GPS as fallback strategy in the sense of being always best positioned. We evaluated the positioning accuracy in our university’s lab environment in terms of hits and misses and investigated the effect of various time window sizes for the frequency measurement of the fingerprint. The symbolic location model can be applied for example to adapt the mobile device to different contexts, e.g. automatically mute the ringtone in meeting rooms, trigger location-dependent rules and events, or disclose the current location to friends.
Modeling of Multi‐level Indoor Environments: Wayfinding Support and Empirical Studies
Christoph Stahl and Stefan Münzer
Tutorial, held in conjunction with the International Conference on Spatial Cognition 2010, Mt. Hood / Portland, Oregon
[link]
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In this half-day tutorial, we introduce the YAMAMOTO modeling toolkit that has been developed for the rapid modeling and visualization of multi-level buildings in 3-D, including the furnishing and landmark objects. YAMAMOTO provides a route finding component that automatically generates visual route descriptions to support indoor navigation and wayfinding tasks in complex buildings. The tool can be of interest for researchers, architects, and teachers concerned with indoor wayfinding, visualization, and spatial learning. We will show how to apply the tool for the modeling of real or fictive buildings and demonstrate how to explore such a building model from different perspectives and viewpoints in desktop virtual environments. We will explain how to use the toolkit’s dedicated features to create visual route descriptions for wayfinding. We further report on how we have utilized YAMAMOTO models for empirical studies on wayfinding and spatial learning.
Modeling and Simulating Ambient Assisted Living Environments - A Case Study
Tim Laue and Christoph Stahl
In Proceedings: Ambient Intelligence and Future Trends-International Symposium on Ambient Intelligence (ISAmI 2010), Advances in Soft Computing, Vol.72, pp. 217-200. Berlin: Springer. Http://www.springerlink.com/content/e4247wl8g5377230/?p=06a9ebf68e744432a0d65189f6a013d5
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Modeling the layout of an apartment -- including different furniture configurations and several moving elements -- is a non-trivial task, especially if accessibility has to be assured e.g. for wheelchairs.
In this paper, we describe a two-staged example for such a task by connecting two different applications: In the first step, the Yamamoto toolkit is used to efficiently model the building structure and to plan the furnishing of the environment in 3D. Afterwards, the desired configuration becomes exported to SimRobot, a robot simulator based on rigid body dynamics. Thereby, a realistic evaluation of the physical configuration becomes possible by interactively driving an electrical wheelchair through the environment.
Seamless Resource Adaptive Navigation
Tim Schwartz, Christoph Stahl, Jörg Baus, and Wolfgang Wahlster
In: Matthew Crocker and Joerg Siekmann (eds). Resource-Adaptive Cognitive Processes. Cognitive Technologies Series. Springer Verlag, Berlin, 2010, pp. 239-265
Local Danger Warnings for Drivers: The Effect of Modality and Level of Assistance on Driver Reaction
Yujia Cao, Angela Mahr, Sandro Castronovo, Mariet Theune, Christoph Stahl, and Christian Müller
IUI 2010 (to appear)
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Local danger warning is an important function of Advanced
Driver Assistance Systems (ADAS) to improve the safety
of driving. The user interface (the warning presentation) is
particularly crucial to a successful danger avoidance. We
present a user study investigating various warning presentations
using a scenario of emergent road obstacles. Two
presentation factors were selected: modality and level of assistance.
The modality factor had 4 variants: speech warning,
visual and speech warning, visual warning with blinking
cue, and visual warning with sound cue. The level of assistance
varied between with or without action suggestions
(AS). In accordance with the ISO usability model, a total
of 6 measurements were derived to assess the effectiveness
and efficiency of the warnings and the drivers’ satisfaction.
Results indicate that the combination of speech and visual
modality leads to the best performance as well as the highest
satisfaction. In contrast, purely auditory and purely visual
modalities were both insufficient for presenting high-priority
warnings. AS generally improved the usability of the warnings
especially when they were accompanied by supporting
information so that drivers could validate the suggestions.
2009
Spatial Modeling of Activity and User Assistance in Instrumented Environments
Christoph Stahl
Dissertation, Saarland University, 2009
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This dissertation presents a design method for proactive user assistance systems in instrumented environments. The method addresses typical design issues, such as the modeling of users’ needs and the choice and placement of sensors and actuators for human-environment interaction. The design process is supported through the combination of a geometric environment model and a situational semantic activity model. The geometric model is used to visualize the spatial context, in which the activities that are to be supported take place. The activity model is derived from Activity Theory and hierarchically represents tasks and activities in their situational context. Both models are linked by an ontology and form a hybrid location model. To support the method, we implemented a map modeling toolkit that allows to geometrically represent built environments in 3-D, and to model their furnishing and instrumentation with sensors and actuators. Of particular importance was the development and integration of an ontology-based activity editor. Furthermore, the toolkit facilitates the development of navigational aid through a route finding algorithm. The work concludes with five use cases that describe how the method and modeling toolkit have been applied for the design and development of intelligent environments and navigational aid for indoor and outdoor spaces. It also highlights how Dual Reality settings have contributed to the simulation of the developed assistance systems.
UbisWorld 3.0: a Semantic Tool Set for Ubiquitous User Modeling
Dominikus Heckmann, Matthias Loskyll, Rafael Math,
Pascal Recktenwald, Christoph Stahl
Demonstration description in online proceedings of First International Conference on User Modeling, Adaptation, and Personalization (UMAP 2009)
[ DOWNLOAD NOTE ]
show abstract
Ubiquitous User Modeling looks at personalization within
smart environments, tries to resolve problems of diversity of user modeling
techniques and representations by mediation of user models, and
bases on semantic standardization of user modeling enabling user modeling
data exchange and sharing by using a common user modeling ontology
and language. This paper describes the initial work done in the
UbisWorld 3.0 project, a tool set of semantic web and Web 2.0-like services
with the distributed management of scrutable user models, as well
as the foundations for a distributed user model ontology development.
This demonstration description previews only selected aspects of the new
data types, implementation issues and the user interfaces. The complete
system can be tested online as registered user at www.ubisworld.org.
2008
An Activity-Based Approach to the Design of User Assistance in Intelligent Environments
Christoph Stahl, Dominikus Heckmann, Michael Schneider, Alexander Kröner
Capturing Ambient Assisted Living Needs, International Workshop at AmI 2008 Conference, November 19th 2008, Nürnberg.
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Designing user assistance systems in intelligent environments poses many challenges. The system has to provide useful support for its user in everyday situations, while keeping the user interface as simple as possible. This requires a well-founded understanding of the user’s needs, and deep knowledge of pervasive human-computer technology, such as RFID sensors and computer vision. In this paper, we present a new design method, based on Activity Theory, and a toolkit that supports the designer of ambient intelligence systems. The toolkit integrates a geometric location model with a symbolic activity model, so that the typical activities of the user can be analyzed with respect to the environment in order to identify useful assistance features. Furthermore, the system supports the designer to make the necessary decisions for the instrumentation of the environment, i.e. which sensors to use and where to place them.
Learning of Visual Route Instructions for Indoor Wayfinding
Stefan Münzer and Christoph Stahl
Hölscher, C. (Ed.) Spatial Cognition 2008 Poster Proceedings. International Conference on Spatial Cognition, Sept. 15-19, 2008, Freiburg, Germany. SFB/TR8 Report No. 016-08/2008. Universität Bremen / Universität Freiburg.
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Visitors of complex buildings might be presented with individual visual route instructions shown on ambient displays. Such route instructions can automatically be generated by a modelling software. It was investigated which route instruction format would foster human wayfinding most effectively in a naturalistic wayfinding scenario in a real building. Egocentric, view-based formats (animated virtual walk of the route, sequence of pictures of decision points) were compared to maps with route indication. In each of the three conditions, 16 participants were tested individually. Participants watched the route instruction passively and then walked the route through the real building. Critical wayfinding errors showed a clear advantage of the animated “virtual walk” instruction format. This advantage is explained by the accordance of the virtual walk with the real wayfinding experience. This includes the “analogous” trans-mission of turning information in the form of movements of the virtual camera.
New Perspectives on Built Environment Models for Pedestrian Navigation
Christoph Stahl
Hölscher, C. (Ed.) Spatial Cognition 2008 Poster Proceedings. International Conference on Spatial Cognition, Sept. 15-19, 2008, Freiburg, Germany. SFB/TR8 Report No. 016-08/2008. Universität Bremen / Universität Freiburg.
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We present a map modelling toolkit that meets the special requirements of pedestrian navigation in intelligent environments. Its central component is a graphical editor, which supports the geometric modelling and visualization of built environments in 3D. Multiple levels and their interconnections, such as ramps and staircases, can be represented through layers. The toolkit also integrates a route finding module for pedestrian navigation applications. The model and the route can be shown as an orthogonal (map-like) projection or from different perspective viewpoints; the allocentric viewpoint shows the model from outside (bird’s view), the egocentric viewpoint shows the model from the user’s perspective inside the building. Landmark objects can be included and the visibility of signage or public displays can be virtually evaluated using the avatar. Various animations can be created to visualize the route, including transitions between the perspectives.
2007
Räumliches Lernen mit Navigationssystemen
Stefan Münzer, Hubert Zimmer, Jörg Baus and Christoph Stahl
magazin forschung, Universität des Saarlandes, 2/2007, S. 2-7
Providing Individual Route Instructions for Indoor Wayfinding in Complex, Multi-Level Buildings
Stefan Münzer, Christoph Stahl
GI-Days 2007 Young Researchers Forum, Sept. 10-12, Münster, ifgi Prints series - to appear
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The present paper describes an interdisciplinary approach to personalized indoor wayfinding in complex multi-level buildings. Users are presented with individual visual route instructions on ambient displays in the environment. These instructions are provided by a modelling software which calculates individual paths through a virtual model of the building. Since users should be able to comprehend and learn such route instructions easily and quickly, the question arises which instructional format will foster human wayfinding in this scenario most effectively. An empirical study was therefore designed. Egocentric, view-based visual instruction formats are compared to a map-based, allocentric format. Currently, data on route learn-ing and wayfinding success after being presented with route instructions in different formats are collected in a complex, multi-level building. The results of this study will contribute to the development of design guidelines for cognitively adaequate indoor route instructions, in particular for egocentric and animated visual formats.
The Roaring Navigator: A Group Guide for the Zoo with Shared Auditory Landmark Display
Christoph Stahl
In: Proceedings of the 9th International Conference on Human Computer Interaction with Mobile Devices and Services (MobileHCI '07). ACM (SIGCHI), New Nork. pp. 219-222
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In this paper, we introduce a shared auditory landmark display which conveys spatial survey knowledge and navigational aid to multiple users. Our guide is situated in a zoo environment, so we use recordings of animal voices to indicate the location of the animal enclosures. Spatial audio manipulates the volume and stereo balance of the sound clips, so that the listener can identify their distance and direction. The system also proactively presents audio clips with detailed information about each animal. To avoid the typical effect of social isolation through audio guides, we use shared audio so that the same sounds will be presented to each user at the same time. We have conducted an initial user study of paired visitors in the zoo to evaluate the usability of the system with positive results. The participants reported that the system is easy to use and has a stimulating influence on the communication between the visitors. As a further result, the study indicates that ‘lightweight’ navigational aid can be sufficient for wayfinding tasks in certain environments, which provides only the linear distance and direction of the destination.
Here and Now: A User-Adaptive and Location-Aware Task Planner
Christoph Stahl, Dominik Heckmann, Tim Schwartz, Oliver Fickert
International Workshop on Ubiquitous and Decentralized User Modeling (UbiDeUM'2007), pp. 52-63
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In this paper, we present a ubiquitous location-based task planner
that integrates a to-do list and a schedule/calendar with route knowledge and
adapts both its view and alarms to the user’s current situation. The task planner
is hosted on a web server and can be accessed from everywhere via a mobile
Web terminal, such as a mobile phone or notebook, or a public display
infrastructure which recognizes the user by their Bluetooth-device. Tasks can
be localized by specifying a certain location where the task can be
accomplished, such as an office or a store. Alternatively, a category can be
chosen from an ontology that includes activities like shopping, sports or
traveling by airplane. Since the task planner is likely to include dozens of tasks
for the near future, it is too large to be browsed on the go. Therefore the planner
implements a ‘here-and-now’ view, which adapts to the current time/date and
location of the user. Based on knowledge about the purpose, address and
opening hours of locations and routes, the task planner is able to filter for tasks
that can be accomplished nearby, considering the time to reach the location and
other deadlines. A second feature is an adaptive reminder, which considers the
time that is needed to travel to the specified location of a task.
2006
Sharing Control of Dispersed Situated Displays between Nomadic and Residential Users
Christian Kray, Keith Cheverst, Daniel Fitton, Mark Rouncefield, Corina Sas, Christoph Stahl
In Proceedings of the 8th International Conference on Human Computer Interaction with Mobile Devices and Services (MobileHCI 2006), ACM Press, 2006, pp. 61-68
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As the number of public displays in the environment increases,
new opportunities open up to improve situated interaction
and to enable new kinds of applications. In order
to make distributed display resources available to nomadic
users, a key issue to address is how control can be dynamically
shared between display users. It is important to study
how control over a shared display can be acquired, released
or shared by nomadic and residential users given their competing
demands for display resources.
In this paper, we present a system and a user study investigating
these issues in the context of two applications
both competing for display resources provided by a deployment
of interactive office doorplates. The first application
(Hermes II) provides situated note leaving and messaging
services whereas the second one (GAUDI) supports user
navigating a university department. Office occupants (i. e.
residential users) can control whether the navigation application
may (temporarily) use their doorplate display (thus
giving priority to the navigation needs of nomadic users to
the department). We report on findings from a user study,
and discuss interface design implications for specifying display
control.
Modelling and Designing User Assistance in Intelligent Environments (MODIE 2006)
Thomas Pederson, Helder Pinto, Michael Schmitz, Christoph Stahl, Lucia Terrenghi (Eds.)
SFB 378 - Resource-Adaptive Cognitive Processes, Memo Nr. 86: Modelling and Designing User Assistance in Intelligent Environments (MODIE 2006) Workshop in Conjunction with the 8th International Conference on Human Computer Interaction with Mobile Devices and Services (MobileHCI 2006), ISSN 0944-7822, Saarland University
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Ubicomp research continually develops novel interaction techniques, sensing technologies, and new ways of presenting personalized information to the user. Gradually, companies operating in environments such as airports, museums or even shopping malls are becoming aware of the potential benefits in letting such technologies assist their users and customers. Intelligent environments are predicted to aid their users in pursuing their activities, such as wayfinding or shopping, through the situated presentation of personalized information. However, due to the large design space that ranges from wearable computing to public displays, the conceptual and technological choices pose new challenges to the designer of such user-assistance systems.
The MODIE workshop aims towards models, principles and methodologies, which guide the designer of an intelligent environment in the early stages of the development process, such as task and requirements analysis and conceptual design.
Simulating and Evaluating Public Situated Displays in Virtual Environment Models
Christoph Stahl, Jens Haupert
International Workshop on Modelling and Designing User Assistance in Intelligent Environments (MODIE 2006). In:
SFB 378 - Resource-Adaptive Cognitive Processes, Memo Nr. 86: Thomas Pederson, Helder Pinto, Michael Schmitz, Christoph Stahl, Lucia Terrenghi (Eds.): MODIE 2006, ISSN 0944-7822, pp. 32-35, 2006. Saarland University
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In this position paper, we address the problems that arise during the design phase of intelligent environments that make use of public situated displays for user assistance. We propose a new design process, which is based on an architectural model of the environment. It employs a toolkit that allows the designer of an intelligent environment to verify the visibility of displays from various virtual viewpoints before they are actually acquired and deployed. Our approach furthermore allows the early evaluation of application prototypes. We mirror the screens of real machines to the virtual displays and use an avatar as a positioning loopback device in order to test the behavior of context-aware presentations.
Taking Location Modelling to new Levels: A Map Modelling Toolkit for Intelligent Environments
Christoph Stahl and Jens Haupert
2nd International Workshop on
Location- and Context-Awareness. In:
M. Hazas, J. Krumm, and T. Strang (Eds.): LoCA 2006, LNCS 3987, pp. 74 – 85, 2006. Springer-Verlag Berlin Heidelberg.
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[BibTeX]
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We present a map modelling toolkit that meets the special requirements of pedestrian navigation in intelligent environments. Its central component is a graphical editor, which supports geometric modelling of architectural ground plans through polygon meshes. Multiple levels and their interconnections, such as ramps and staircases, can be represented through the aid of layers. In order to support a full range of activities, from travelling to interacting with pervasive user interfaces, coarse models on an outdoor scale can be hierarchically refined by submodels on building and room scales. The XML-encoded models can be useful for positioning systems, referencing spatial context and for route finding through multi-story buildings. Besides the editor, the toolkit provides a routing module for pedestrian navigation.
Towards a Notation for the Modeling of User Activities and Interactions Within Intelligent Environments
Christoph Stahl
3rd International Workshop on the Tangible Space Initiative (TSI 2006). In: Thomas Strang, Vinny Cahill, Aaron Quigley (Editors). Pervasive 2006 Workshop Proceedings, Deutsches Zentrum für Luft- und Raumfahrt, pages 441-452. ISBN 978-3-00-018411-6
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The design of ubiquitous computing systems for pedestrian assistance in large and complex environments, such as airports, museums or conferences, poses new challenges to existing development processes. The designer of such a system has to specify typical activities within the environment and how the system supports them, and decide which sensors and devices will be used for interaction. We propose a new design process, which extends the scenario-based design approach through the use of a more structured model of user activities and human-computer interaction in intelligent environments.
2005
Navigational- and Shopping Assistance on the Basis of User Interactions in Intelligent Environments
C. Stahl, J. Baus, B. Brandherm, M. Schmitz and T. Schwartz
Proceedings of the IEE International Workshop on Intelligent Environments (IE 2005), University of Essex, Colchester, UK, 2005
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[BibTeX]
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This paper presents an overview about ongoing work in the project REAL, where we have set up the Saarland University Pervasive Instrumented Environment (SUPIE). In particular we introduce the intelligent environment’s architecture, which serves as the basis for different services and applications running in the environment and supporting their users in different tasks. On the basis of this information we outline our user and location-modeling component needed to establish the navigational– and shopping-assistants developed so far. Both assistants support their users with especially customized presentations. These presentations will be automatically scheduled and presented on public displays in the environment, as explained in the remarks about the presentation manager. Finally, we provide a short outlook on planned future work in the project.
Managing Presentations in an Intelligent Environment
Christoph Stahl, Michael Schmitz, Antonio Krüger, Jörg Baus
MU3I Workshop at IUI 2005, San Diego, USA.
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Intelligent environments enable users to receive information
from a variety of sources, i.e. from a range of displays
embedded in those environments. From a services
perspective delivering presentations to users in such an
environment is not a trivial task. While designing a service
it is, for example, not clear at all which displays will be
present in the specific presentation situation and which of
those displays might be locked by other services. It is
further unclear if other users are able to see the
presentation, which could cause problems for the presentation
of private information in a public space. In this paper
we propose a solution to this problem by introducing the
concept of a presentation service that provides an
abstraction of the available displays. The service is able to
detect conflicts that arise when several users and services
try to access the same display space and provide strategies
to solve these conflicts by distributing presentations in
space and time. The service also notifies the user by a alarm
signal on a personal device each time a presentation is
shown on a public display in order to disambiguate content
between multiple users.
Resource-Adaptive Personal Navigation
Jörg Baus, Antonio Krüger, Christoph Stahl
Chapter in: O. Stock and M. Zancanaro (eds.), Multimodal Intelligent Information Presentation, pages 71-93, Springer, 2005, ISBN: 1-4020-3049-5.
2004
Using Semantic Web Technology for Ubiquitous Location and Situation Modeling.
Christoph Stahl, Dominik Heckmann
The Journal of Geographic Information Sciences, CPGIS: Berkeley, Vol. 10, No. 2., December 2004, pages 157-165.
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[BibTeX]
[ACM ref]
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We use semantic web technology to utilize the world wide web for a large-scale ubiquitous (qualitative and geometric) location model, in order to achieve shareability and extensibility at low operational cost. Our intention is to model location and user characteristics, in order to realize location aware applications with a focus on pedestrian navigation in buildings and situated user interaction. We present the ubiquitous symbolic location and situational context model UbisWorld and the tool Yamamoto for the modeling of hierarchical geometrical maps.
Using Semantic Web Technology for Ubiquitous Hybrid Location Modelling
Christoph Stahl, Dominik Heckmann
1st Workshop on Ubiquitous GIS, in conjunction with 12th International Conference on Geoinformatics, 7-9 June 2004 - Gävle, Sweden.
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[BibTeX]
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We use semantic web technology to utilize the world wide web for a large-scale ubiquitous hybrid location model, in order to achieve shareability and extensibility. Our intention is to model location and user characteristics, in order to realize location aware applications with focus on situated user interaction and pedestrian navigation. We present the ubiquitous symbolic location model UbisWorld and the tool Yamamoto for the modeling of hierarchical geometrical maps.
REAL: Situated Dialogues in Instrumented Environments
C. Stahl, J. Baus, A. Krüger, D. Heckmann, R. Wasinger, M. Schneider
Workshop on Invisible and Transparent Interfaces at AVI 2004, Gallipoli, Italy, 2004, pp. 10-15.
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We give a survey of the research project REAL, where we investigate how a system can proactively assist its user in solving different tasks in an instrumented environment by sensing implicit interaction and utilising distributed presentation media. First we introduce
the architecture of our instrumented environment, which uses a blackboard to coordinate the components of the environment, such as the sensing and positioning services and interaction devices. A ubiquitous user model provides contextual information on the users
characteristics, actions and locations. The user may access and control their profile via a web interface. In the following, we present two mobile applications to employ the environmental support for situated dialogues, a shopping assistant and a pedestrian navigation system. Both applications allow for multi-modal interaction through a combination of speech, gesture and sensed actions such as motion.
The Connected User Interface: Realizing a Personal Situated Navigation Service
Antonio Krüger, Andreas Butz, Christian Müller, Christoph Stahl, Rainer Wasinger, Karl-Ernst Steinberg, Andreas Dirschl
In Proceedings of the 9th International Conference on Intelligent User Interfaces (IUI 2004), ACM Press, 2004, pp. 161-168.
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[BibTeX]
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Navigation services can be found in different situations and contexts: while using the web with a desktop PC, in cars, and more recently also when being a pedestrian on PDAs. These services are usually well designed for their specific purpose, but fail to work in other situations. In this paper we present an approach that connects a variety of specialized user interfaces to achieve a personal navigation service spanning different situations. We describe the concepts behind the BPN (BMW Personal Navigator), an entirely implemented
system that combines a desktop event and route planner, a car navigation system, and a multi-modal, in- and outdoor pedestrian navigation system for a PDA. Rather than designing for one unified UI, we focus on connecting specialized UIs for desktop, in-car and on-foot use.
2003
Adapting Spoken and Visual Output for a Pedestrian Navigation System, based on given Situational Statements
Rainer Wasinger, Dominika Oliver, Dominik Heckmann, Bettina Braun, Boris Brandherm, Christoph Stahl
11th GI-Workshop on Adaptivity and User Modeling in Interactive Software Systems (ABIS-2003), Karlsruhe, 2003, pp. 343-346.
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As mobile devices become more and more complex, there is an increasing desire for these devices to adapt to their users. This paper identifies parameters for different input
sources (user, device and environment), and the parameters of media output (speech, graphics, sound and text), that may be modified to tailor user presentation in a pedestrian navigation system. We also provide an initial insight into some of the causal relationships between our input and output parameters, with a specific focus on the effects that speech can contribute to the presentation of media output.
M3I in a Pedestrian Navigation & Exploration System
Rainer Wasinger, Christoph Stahl, Antonio Krüger
5th International Symposium on Human Computer Interaction with Mobile Devices (Mobile HCI 2003), Udine, Italy, September 8-11, 2003, Springer: Lecture Notes in Computer Science, Vol. 2795, Chittaro, Luca (Ed.), ISBN: 3-540-40821-5, pp. 481-485.
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In this paper, we describe a near-complete Pocket PC implementation of a mobile multi-modal interaction (M3I) platform for pedestrian navigation. The platform is designed to easily support indoor and outdoor navigation tasks, and uses several modalities for the presentation and user input. Whereas 2D/3D-graphics and synthesized speech are used to present useful information on routes and places, embedded speech and gesture recognition allow for situated user interaction.
Robust speech interaction in a mobile environment through the use of multiple and different media types
Rainer Wasinger, Christoph Stahl, Antonio Krüger
8th European Conference on Speech Communication and Technology (EUROSPEECH 2003 - INTERSPEECH 2003), Geneva, Switzerland, September 1-4, 2003, ISCA Archive, pp. 1049-1052.
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Mobile and outdoor environments have long been out of
reach for speech engines due to the performance limitations
that were associated with portable devices, and the
difficulties of processing speech in high-noise areas. This
paper outlines an architecture for increasing speech
recognition rates in a mobile pedestrian indoor/outdoor
navigation environment, through the use of a media fusion
knowledge component.
2002
A Framework for Intelligent Instrumented Environments
Christoph Stahl
Two-page abstract in the UBICOMP 2002 doctoral consortium notes.
Location Dependent Generation of Sketches for Mobile Indoor Route Descriptions
Christoph Stahl, Antonio Krüger, Jörg Baus
ECAI 2002 Workshop notes on Artificial Intelligence in Mobile Systems (AIMS).
Positionsabhängige Kartengenerierung für mobile Fußgängernavigationssyteme
A. Krüger, C. Stahl, J. Baus
Simulation und Visualisierung, Magdeburg 28.Feb.-1. März 2002. SCS-Verlag, ISBN 1-56555-234-2, ISBN 3-936150-15-x.
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Navigationssysteme werden in Zukunft den Sprung vom Auto in die Westentasche
schaffen und so auch Fußgänger in den Genuß der personalisierten Wegbeschreibung
kommen lassen. Dabei wird neben der verbalen Beschreibung der Route insbesondere
geeignete Graphiken zum Einsatz kommen. Diese Graphiken müssen in Abhängigkeit
einer Vielzahl von Parametern erstellt werden, so daß eine dynamische Generierung der
Graphiken an dieser Stelle sehr sinnvoll ist. Der vorliegende Artikel befaßt sich daher
mit der Frage wie inkrementelle 2D-Wegbeschreibungen aus einem 3D-Modell, auf
den jeweilgen Beutzerkontext zugeschnitten, generiert werden können.
2001
VAI: Ein System zur intelligenten Navigation durch VRML Welten mittels graphischer Abstraktion
Christoph Stahl
Diplomarbeit an der Universität des Saarlandes
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Heute wird der Betrachter von VRML Welten bei der Navigation vor verschiedene
Probleme gestellt. Der Wunsch nach einer realitätsnahen Darstellung fordert auf der
einen Seite hohe Rechenleistung zur Bildgenerierung. Auf der anderen Seite wird der Betrachter durch die Darstellung zuvieler Details von seinem Navigationsziel abgelenkt. Desweiteren führt gerade ein Hauptvorteil von VRML, die einfache Interaktion mit Objekten, häufig zu einem Problem bei der Navigation. Dies liegt daran, daß die Interaktionsmöglichkeiten für den Betrachter nicht klar erkennbar sind, sondern nur durch Probieren herausgefunden werden können. Ausgehend von diesen Schwierigkeiten wurde in dieser Arbeit das Hilfssystem VAI entwickelt. Das System verwendet erstmalig die Technik der graphischen Abstraktion, die im Prozess der Bilderzeugung sowohl auf der Modell- als auch auf der Generierungsebene
eingesetzt wird. Der Betrachter der Welt bekommt durch VAI eine Konsole zur Verfügung gestellt, mit der er interaktiv den Abstraktionsgrad der einzelnen Objekte direkt manipulieren kann. Ergänzend sind funktionale Sichten auf dieWelt abrufbar, um interaktive Elemente und Hyperlinks graphisch besonders hervorzuheben. Die Arbeit beschreibt Architektur und Implementation zweier Varianten des VAI Systems
und demonstriert dessen Möglichkeiten anhand von Anwendungsbeispielen.
1998
Graphical Abstraction and 3D-Hypergraphics: Exploring Large Geometrical 3D-Models.
Antonio Krüger, Christoph Stahl
Combining AI and Graphics for the Interface of the Future (ECAI 1998), Brighton, UK, August 1998.
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The navigation of complex 3D-models is complicated because of two circumstances. First the huge amount of 3D-data slows down the interaction and second the variety of details is likely to overload the cognitive capacities of the viewer. In such a situation relevant details are often difficult to find. This paper describes an interactive version of the level-of-detail concept (LOD) to speed up the visualization process and to reduce irrelevant details at the same time.
Intelligente Navigation in 3D-Welten: Zur Rolle graphischer Abstraktion
Antonio Krüger, Christoph Stahl
Simulation und Visualisierung, SCS-Verlag, Magdeburg, 5.-6. März 1998.
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Das Navigieren in komplexen 3D-Welten wird durch zwei Faktoren erheblich erschwert:
Zum einen stellt die enorme Datenmenge große Anforderungen an die Hardware
der Visualisierungsplattform, zum anderen wirkt der Detaillreichtum, der diesen
Aufwand erforderlich macht, oft ablenkend und kann im Extremfall dazu führen, daß
der Benutzer den Überblick verliert und die Navigation von einem bekannten Startpunkt
aus neu starten muß. Dieser Beitrag diskutiert einen Lösungsvorschlag, der versucht, beiden Problemen gerecht zu werden. Durch die graphische Abstraktion von Modellteilen und der damit einhergehenden Vereinfachung des 3D-Modells werden Rechnerressourcen gespart und dem Navigierenden wird gleichzeitig ein Überblick ermöglicht, da potentiell ablenkende Details unterdrückt werden. Während der Navigation wird der Detaillierungsgrad automatisch durch das System oder interaktiv durch den Navigierenden angepaßt. Ziel dieser semi-automatischen graphischen Abstraktion ist ein auf das Navigationsziel und auf die Leistung des visualisierenden Rechners möglichst optimal zugeschnittener Abstraktionsgrad.
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Einführung in die Methoden der Künstlichen Intelligenz (Methods of A.I.)
(SS 2010)
Einführung in die Methoden der Künstlichen Intelligenz (Methods of A.I.)
(SS 2010)
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