MNISIKLIS: Indoor LBS for All

Vassilis Papataxiarhis, V.Riga, V. Nomikos, O.Sekkas, K.Kolomvatsos, V.Tsetsos, P. Papageorgas, S.Vourakis,

S.Hadjiefthymiades, and G. Kouroupetroglou

vpap@di.uoa.gr

Department of Informatics and TelecommunicationsUniversity of Athens – Greece

LBS-2008, 26-28 Nov. 2008, SalzburgLBS-2008, 26-28 Nov. 2008, Salzburg

Introduction MNISIKLIS - Project details

• National Project (July ’06 – December ‘07)

Consortium

Main Goal• Provide universal indoor LBSs focusing on navigation

Unisystems S.A.

National and Kapodistrian University of Athens (NKUA)

Technological Educational Institute of Piraeus

Architecture

Loca

tion

Fus

ion

Sensors and positioningtechniques

Positioning Interface

Usermodel

Spatialmodel

UserDevice

Location ServiceAlgorithms

User InteractionAlgorithms

Middleware

Content description

model GIS

SCMSDevicemodel

Positioning Subsystem

ApplicationModels

Peripheral Systems

Input/Output Equipment

LBS

Content RepresentationInterfaces

InteractionSoftware

User Interaction Subsystem

Pos

ition

ing

Equ

ipm

ent

Services

Static Navigation

Dynamic Navigation

Where-Am-I Service

Exploration Service

Nearest Points-Of-Interest (POI)

Positioning Subsystem Sensing technologies

• UHF RFIDs (i.e tags and reader)

• WiFi access points (RSSI)

• dead reckoning for pedestrian users

• 3-axis electronic compass

• 3-axis accelerometer

Fusion techniques

• two levels of data fusion in the Location Server

• 1rst level: RFID tags and WLAN measurements

• 2nd level: 1rst level output + DR estimation

Sensing Components Sensor unit attached to the user’s belt data transfer through Bluetooth to the PDA

Dead reckoning filter raw accelerometer data step detection step length estimation predicted walking distance of m steps

Data collector (PDA) executes the DR algorithm collects RFID and RSSI measurements data transfer through WLAN to the Location Server

Location Server (1/3)

N symbolic locations Li

bidirectional communication with the data collector

two levels of fusion

final estimation of user’s position

Location Server (2/3) Communication component: communication with the data collector validation of received data quantization of the WLAN RSSI values received vector’s format:

<userId,IE_Idi=valuei,X=x1,Y=y1,Z=z1,Orientation>

1rst level fusion engine: Dynamic Bayesian Network (DBN) based on previous estimation of user's position probability distributions - XMLBIF file Output: <Pb1,Pb2,…,PbN>

Location Server (3/3)

DR data converter: 2D Euclidean distance (di) definition of threshold dt probability reversely proportional to di

2

Output: <Pc1,Pc2,…,PcN >

2nd level fusion engine: weights wb+wc=1 combination formula: Pi=wb*Pbi+wc*Pci Output: location with the highest probability feedback for the DR and DBN update database

Metadata

Flo o r M a p

C o rrid o rs

Na vig a tio n Po ints

Ro om Entra nc es

Sta irwa ys

...

SpatialDatabase

Instances Creation

Algorithm

Ontology Instances

Expressed in terms of OWL ontologies Spatial model instantiation through GIS metadata

Core Navigation Algorithm

Hybrid rule-based algorithm. Takes into account :• Route complexity• Euclidean route distance• User profile (capabilities and preferences)

Steps:• Create “user compatible” building graph based on user profile and application of access rules (in terms of SWRL)

E.g. WheelChaired_User(?x) ^ Stairway(?y) isObstacleFor(?y,?x)• Find the k-simplest paths• Assign the total cost of each path as a function of rewards and penalties of the total path distance, preferences and perceptual rules

User Interaction Subsystem

Main user groups• Non-disabled• Elderly• With vision loss• Locomotive disabled

Multimodal Interfaces• Visual, Audio and Haptic Modality

Devices• PDA, Tablet PC, Smart Phone, Mobile Phone• Head-mounted screen, braille display, earphones

Functionality of UI subsystem Turn-by-turn algorithm

• Left/right turns

• Distances

• Info about near doors

SVG map capabilitiesE.g., zooming, turning,

moving

Related photo 3 levels of detail

User Evaluation 20 users (5 per user group) 3 predefined scenarios Evaluation through questionnaires Positive Comments

• Dynamic Navigation• Menu• Sufficient instructions

Negative Comments• Delay in the delivery of instructions

Implementation Details ESRI ArcGIS software

PostGIS spatial DB

Batik SVG Toolkit (Apache Foundation)

Protégé Ontology Editor

Knowledge Representation Languages• Ontology models in OWL-DL

• SWRL rules

Jess for reasoning over SWRL

Mascopt Library for graph creation and path search

Contributions and Future Work

Main Contributions• UHF RFID for proximity sensing

• Multi-sensor fusion process

• Multimodal user interfaces

• Human centered service logic

Future Work• Landmark-based navigation

• Kalman filtering for DR

• Path prediction techniques

QUESTIONS?

Thank you!

http://speech.di.uoa.gr/mnisiklis