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Design and Implementation Issues for Explorative Location-based Applications:
The NexusRallye
Daniela Nicklas, Nicola Hönle, Michael Moltenbrey, Bernhard Mitschang
GeoInfo 2004, 22. November 2004
Universität Stuttgart, Germany
Center of Excellence 627:Spatial World Models for Mobile Context-Aware Applications
University of StuttgartCenter of Excellence 627
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Overview
Motivation
A task-oriented approach
Sample application: the NexusRallye Requirements
Data Model
Context management: the Nexus platform Platform architecture
Access patterns
Lessons learned
University of StuttgartCenter of Excellence 627
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Campus Universität Stuttgart, Germany
Scenario
University of StuttgartCenter of Excellence 627
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A freshmen at the University
libraryCS building
cafeteria
examinationoffice
University of StuttgartCenter of Excellence 627
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Welcome days for CS freshmen
First day: Guided tours experienced students show the campus to the freshmen
explain the most important things for "survival"
welcome party
Second day: the Campus rally morning: freshmen teams get sheets of paper with tasks, e.g.:
"How many steps are in the math building from first to eigth level?"
"What is the registration number of the examination on databases?"
"Who is Fabiola and what is she doing in the students lab?"
"Write a short poem on the food offered today in the cafeteria."
afternoon: teams return, jury assesses the answers
winner team gets prize, another party
University of StuttgartCenter of Excellence 627
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Features of the rally game
tasks get the players to move around require location knowledge
require communication with people
reuse of tasks from last year, add new ones
general & specific tasks (university & computer science)
possible benefits of electronic version: use of existing information spaces (maps, web sites, ...)
easy reuse of tasks
dependency of tasks
case study for location-based applications (research goal)
University of StuttgartCenter of Excellence 627
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A task-oriented approach
what types of tasks to support?
task
questiontask
actiontask
multiplechoice free
textvalue
...find/goTo
taskbringTo
task...
target:• specific/general• stationary/moving
University of StuttgartCenter of Excellence 627
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Overview
Motivation
A task-oriented approach
Sample application: the NexusRallye Requirements
Data Model
Context management: the Nexus platform Platform architecture
Access patterns
Lessons learned
University of StuttgartCenter of Excellence 627
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Requirements for NexusRallye
get benefits: use of existing information spaces (maps, web sites, ...)
easy reuse of tasks
dependency of tasks
support different types of tasks
support different rallies sharing tasks
automatic scoring (if applicable), else: sending results to the jury (e-mail)
multiplayer game
University of StuttgartCenter of Excellence 627
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Use Case
player searches for rallies in her surrounding
player (or team of players) signs up for a rally
player gets initial tasks
dependencies between tasks lead player to (multiple) paths through the rally
after solving enough tasks or a time-out occured, the game ends
player gets result
University of StuttgartCenter of Excellence 627
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Association of tasks and rallies
tasks can have more than one location
for different rallies, a task can be relevant at different locations
Solution: concept of Virtual Task Container (VTC) a rally consists of VTCs
each VTC has a certain visibility area
VTC references tasks to that area, which get available for player if she enters it
University of StuttgartCenter of Excellence 627
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Sample Rallye Scenario
Campus University of Stuttgart
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24
1
playervirtual taskcontainer withvisibility area
rallye area
?
?
?
?
?
?
?
?
?
?
task
reference
University of StuttgartCenter of Excellence 627
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Tasks can lead to each other
Campus University of Stuttgart
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24
1
playervirtual taskcontainer withvisibility area
rallye area
find Nexuslab
?
?
?
?
?
go to cafeteria
?
?
?
task
reference
cafeteria
Nexus Lab
University of StuttgartCenter of Excellence 627
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Designing a rally
choose tasks: use goTo/bringTo tasks to let users go to certain
locations
choose tasks more or less connected
enable different paths through the rally
model VTCs: associate appropriate tasks
ensure that players always have "something to do"
Easter eggs: VTCs with no prior hint (e.g. moveTo tasks)
University of StuttgartCenter of Excellence 627
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Data Model of NexusRallye
Task
VTC
pos: Pointvisibility: Polygon
references…
ActionTask
QuestionTask
Rallye
name: Stringextent: Polygon
Playername: Stringpos: Point
?
takes part
contains
+ library, street,copy machine,cafeteria, ... context model
University of StuttgartCenter of Excellence 627
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Overview
Motivation
A task-oriented approach
Sample application: the NexusRallye Requirements
Data Model
Context management: the Nexus platform Platform architecture
Access patterns
Lessons learned
University of StuttgartCenter of Excellence 627
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Context Management
Context model: map data (buildings, streets, POIs, ...)
user positions (moving objects)
tasks and game related objects (for BringTo-tasks)
Access: queries and events
Design alternatives: local (on the client)
server-side (one specialized server)
shared (among several servers)
multiplayer game, common model necessary
no reuse of existingcontext data
Nexus platform
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The Nexus Vision: Federated World Models
sensordata
WWWDigital Libraries
Federation
...
LocalContextModels
DigitalInformation Spaces
Context-awareApplications
GlobalContext Model
…MultimodalNavigation
SmartFactory
MobileCity Guide
NexusRallye
University of StuttgartCenter of Excellence 627
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Federation
The Nexus Platform: Architecture
NavigationServiceArea
ServiceRegister
ContextServer
HoardingQuery
Component
ContextServer
ContextServer
register
applicationtier
federationtier
servicetier
EventService GeoCast
Application A Application B
Federation Federation
context models: map data,user positions, tasks, ...
University of StuttgartCenter of Excellence 627
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Federation
NavigationService
Map ServiceQuery
Component
EventService GeoCast
The Nexus Platform: Access Patterns
AreaServiceRegister
ContextServer
Application A
ContextServer
ContextServer
applicationtier
federationtier
servicetier
Application B
QueryComponent
Queries
notification
EventService
notificationregister
Events Value-added Services
NavigationService
MapService
GeoCast
Federation Federation
XML interfaces (over SOAP)
simple spatial query language (AWQL)
spatial model exchange language (AWML)
event registration and notification languages(ERL, ENL)
Navigation routes (NRL), Map (MapPL)...
University of StuttgartCenter of Excellence 627
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Federation
NexusRallye and Nexus Platform
NavigationServiceArea
ServiceRegister
ContextServer 3:
Moving Objects(Players)
HoardingQuery
Component
ContextServer 2:
VTCs, Rallye-Objects
ContextServer 1:CampusModel
register
applicationtier
federationtier
servicetier
EventService GeoCast
NexusRallye Application B
Queries: get rallies,get VTC, get tasks
Events: OnEnter VTC area, solved moveTo/bringTo
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Lessons learned
NexusRallye: good sample application to prove the openess of the
Nexus platform
explorative location-based applications: demand actions from the user by tasks
assumption: user need time and have to see clear advantage
games can do this (advantage: edutainment)
still pending: user studies to prove acceptability and learning success
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www.nexus.uni-stuttgart.de
Obrigada!
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