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

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Campus Universität Stuttgart, Germany

Scenario

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A freshmen at the University

libraryCS building

cafeteria

examinationoffice

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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

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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)

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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

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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

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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

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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

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Sample Rallye Scenario

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1

playervirtual taskcontainer withvisibility area

rallye area

?

?

?

?

?

?

?

?

?

?task

reference

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Tasks can lead to each other

Campus University of Stuttgart

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1

playervirtual taskcontainer withvisibility area

rallye area

find Nexuslab

?

?

?

?

?

go to cafeteria

?

?

?task

reference

cafeteria

Nexus Lab

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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)

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Data Model of NexusRallye

Task

VTCpos: Pointvisibility: Polygon

references …

ActionTask

QuestionTask

Rallyename: 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

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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

WWW Digital Libraries

Federation

...

LocalContextModels

DigitalInformation Spaces

Context-awareApplications

GlobalContext Model

…MultimodalNavigation

SmartFactory

MobileCity Guide

NexusRallye

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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, ...

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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)...

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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!