an ontology based recommendation system an ontology based recommendation system for elderly and...

An Ontology Based Recommendation System

An Ontology Based Recommendation An Ontology Based Recommendation System for Elderly and Disabled PersonsSystem for Elderly and Disabled Persons

Ingo Zinnikus, Anton Bogdanovich, Ralph Schäfer


Structure of the talkStructure of the talk

• SAID: Project Overview– Objectives– General System Description

• Information Service– Agent based personalised access to

the web– Basic features of the recommendation

system: concept representation, probability calculation


Introduction: SAID Introduction: SAID Project DataProject Data

• Contract Number: IST-2000-25024• Started: 1st January 2001.• Duration: 30 months.• Participants:

– EPTRON SA. Spain. (Project Coordinator)– VIA DIGITAL. Spain.– Ayuntamiento de Madrid. Spain.– VESTIA Housing. Netherlands.– CASEMA. Netherlands.– City of The Hague. Netherlands.– DFKI. Germany.– University of Edinburgh. UK.


Introduction: Objectives. Introduction: Objectives.

Objectives:• Improve the Quality of life of the Disabled & Elderly by

contributing to their independent living.• Integrate the Disabled & Elderly in the IST.• Improve and optimise processes and methods for Service

providers.• Advance the state of the art in the field of Digital TV

Interactive services: interfaces, communications, MHP, etc.• Advance the state of the art in the field of personalised

assistants based on Intelligent Agents.As a consequence:• Develop an Integrated Platform able to provide remote

services for the Disabled & Elderly.• Develop innovative Tools for the Service Providers.


Introduction: Innovation. Introduction: Innovation.

• Digital TV: MHP• Active system: Autonomous Agents.• Simplified Interfaces.• Mobile phones.• Complete integrated Service.• Massive Audience.• Viable technologies in an emerging Sector.• Proposed Advantages:

– Reduce Costs.– Extend the number and scope of users.– Extend the Catalogue of Services.– Offer Added Value Services


Introduction: EnvironmentsIntroduction: Environments

Which is the Environment of the End-Users?• Domestic Users at Home.• Mobility Restrictions.• Health Problems.• Accessibility Problems.• Isolation.• Loneliness.• No computer skills.Which is the Environment of the Service Providers ?• Personnel shortage.• Continuous increase of Demand.• Long Waiting Lists.• High costs.• 24h attention. Not possible.• Lack of technical resources.• Lack of technical skills.• Only basic demands are covered.


Introduction: Project DescriptionIntroduction: Project Description

Which is our Proposal ?• Increase the quality of life by promoting independent living.• Increase processes automation and cost reduction.• Extend the catalogue of services.• Offer educational possibilities.• Increase opportunities for personal communication. • Use already existing technical infrastructure.• Strong emphasis on personalisation.How can we do it ?• Personalised attention through remote services.• The TV set as the only interface to the user: DTV.• User Interfaces specifically designed for the Disabled & Elderly.• Active System: Intelligent Software Agents maintain separate personal user profiles

for each user.• Tools to automate and ease the job of social assitants: medical histories, planning,

user profiles, agenda, WAP.• Central Facility able to provide 24h Attention: Videoconferencing, alarms,

supervision, advisers, etc.


Introduction: System diagramIntroduction: System diagram


User environmentUser environment

• OpenTV technology.• 2nd generation STB.• Oversimplified user

interface.• Modem link with server

subsystem.• Information:

– Active mode.– Interactive mode.

• Reminders:– Five reminder types.

• Alarms:– Confirmation.– Reception & Attention

feedback.• Other:

– Services menus.– Entertainment.

Data line Set-Top Box

Remote control

Digital TV input

TV set


Client Platform. Services MenuClient Platform. Services Menu

Options:• Information• Videoconference• Education• Shopping• Household• Back (to TV)• Entertainment

Characteristics:• Clean Design.• Few Concepts.• Two keys• Few Key Strokes.• Few Levels.• “Intelligent .”• Graphics & Sound.


SAID Information Service: Two modesSAID Information Service: Two modes

Interactive Mode:• Information explicitly requested by the user.• Simple user interface.• Personalised list of topics.• Search trees automatically pruned by Intelligent Agents based on

user profile.

Active Mode:• Information automatically searched by the intelligent agents

based on user profile.• Use while watching TV.• Non Disturbing: Flashing Icon -> Summary -> Complete

information


Sources for Information ServicesSources for Information Services

• World Wide Web (WWW)– Direct access of Web pages– Search Bots

• Databases– Internal: SAID database– External: Service providers


Motivation: Why not using a browser?Motivation: Why not using a browser?

• Elderly and disabled people often are reluctant to use the internet because of technophobia.

• The advantage of a browser is a disadvantage for elderly people!

• The user receives not only information s/he looks for but also advertising, “spam” etc.

• Hyperlinks are confusing and lead to information overflow.


Solution: Pre-Selected web pagesSolution: Pre-Selected web pages

• Only a limited set of web pages is selected in order to correspond the needs of elderly and disabled people.

• Web pages are analysed and categorised in advance. Each web page we use has an associated node in an “ontology tree”.

• There is no need to spend time at searching a web page for interesting information


OntologyOntology

TV

Gardening

Wellness

Movie

Sport

Plants

Tips

Seniors

Health

Diseases

All

Simple Ontology

The ontology in SAID serves not only as a knowledge storage but also has a functional constituent.

Each of the tree nodes serves as a container for additional data that points to a specific web page and helps to extract only desirable information from it using predefined rules


Hierarchical StructureHierarchical Structure

Browsing by iterated selection of concepts All

TV Wellness Gardening

MoviesSport Soap Operas

Comedy Action ScienceFiction

Ontology tree

Action


Dynamical InformationDynamical Information

Parsing the web page

ActionURL

RULES

Snatch Gladiator


Ontology: The “Configurator” tool.Ontology: The “Configurator” tool.

• Consists of a tree of predefined topics

• Additional fields for web sites and rules to extract information which can be changed and modified e.g. by a social worker

• Gives the ability to add/rename/delete the concepts of ontology.

• Allows to keep in touch with rapidly changing internet environment and quickly react to it’s changes without any modification of the program’s code.


From an Ontology to User PreferencesFrom an Ontology to User Preferences

• The ontology tree is more a general representation of interesting topics for a type of user than a representation of a specific user’s preferences.

• In order to generate user preferences, we annotate every concept with a supplementary index which represents the user’s interest in this topic.

• Question: how to adapt this index to the user’s preferences?


User Preferences are part of user profileUser Preferences are part of user profile

namesurnameid...preferences

...

PreferencesUser Profile


Steps towards a recommendationSteps towards a recommendation::

• Adapting to the real preferences according to the decisions of the user– Individual estimates of the user’s interests

– The more interactions, the better the estimates

• Predicting possible user interest for a specific object

(web site, text, image, etc.) on the basis of previous decisions


Unobtrusive monitoring of the user’s actionsUnobtrusive monitoring of the user’s actions

• Observation: An object is presented to the user. The user accepts or

rejects the object.

• Meaning: If the user accepts (rejects) the object, her overall evaluation

of the object is probably very high (low).


Counting acceptances and occurrences of topicsCounting acceptances and occurrences of topics

Sport

Football

Racing

Basketball

6/30

2/30

12/30

4/30

6/31

2/31

12/31

4/31

6/31

2/31

13/31

5/31

Itemspresented

RacingRacing


Bayesian Reasoning for tree-like User PreferencesBayesian Reasoning for tree-like User Preferences

)(

)()|(

BP

BAPBAP

)(

)()|(

SportP

SportRacingPSportRacingP

)(

)()|(

SportP

RacingPSportRacingP

)()( RacingPSportRacingP

385.03113

315)|( SportRacingP

For conditional probabilities we have

This means for the example

Since in the case of our ontology we have

We can therefore conclude

which gives us in our example


Shortcoming of this solutionShortcoming of this solution

• Calculation only with expected value, but no probability distribution and variance

• Variance would allow a better estimation of the reliability of a suggestion

use of full Bayesian networks to model more differentiated behaviour !?


Bayesian Networks Bayesian Networks

• Probabilistic inference mechanism• Off-the-shelf tools available for reasoning• Technical properties

– Nodes correspond to random variables: uncertainty is represented in form of probability distribution.

– Edges represent uncertain relations, represented as conditional probability tables.

– Standard algorithms to evaluate networks.


Combining Hierarchy with Bayesian netsCombining Hierarchy with Bayesian nets

A subtree represents a Bayesian net only if the concepts within this subtree are independent of each other.(E.g. ‚TV‘ is a media and therefore not independent of e.g. ‚Wellness‘)

All

Wellness TV

Movie Sport Politics

Action

Preferences

Bayesian net

[0.0,0.1][0.1,0.2][0.2,0.3][0.3,0.4][0.4,1.0]

[0.0,0.1][0.1,0.2][0.2,0.3][0.3,0.4][0.4,1.0]

(3 times)


Crossing link between branches in the hierarchyCrossing link between branches in the hierarchy

Identical or synonymous concepts can be linked together and ...

All

TV Wellness Gardening

EmissionSport Soap Operas

Travelling Gardening Politics

Preferences


Concept is incorporated into the Bayesian netConcept is incorporated into the Bayesian net

... are integrated into a larger Bayesian net

Gardening

Emission

Travelling Gardening Politics

[0.0,0.1][0.1,0.2][0.2,0.3][0.3,0.4][0.4,1.0]

(3 times)

[0,1][1,2][2,3][3,4][4,10]


The Recommendation functionalityThe Recommendation functionality

• On each level an additional node ‘Recommendation’ is offered to the user

• After choosing ‘Recommendation’ concepts in the current subtree with a probability higher than a specific threshold are presented

Browsing the ontology tree is facilitated


ConclusionConclusion

• We presented the SAID system which provides support for elderly and disabled persons

• Information service replaces traditional web Browser by browsing through an ontology tree

• Tree-like ontology allows Bayesian calculation of conditional probabilities as a basis for a recommendation system

an ontology based recommendation system an ontology based recommendation system for elderly and...

Documents

disabled elderly

user interfaces

recommendation system

remote services

catalogue of services

mhpactive system

service providers

services menus