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Enabling Reputation Interoperability through Semantic Technologies

Rehab Alnemr

HPI Research School Chair “Internet Technologies and Systems” of Prof. Dr. Christoph Meinel

Approaches?

Trust models

■ serve as a decision criterion for an agent to engage in activities

One of the approaches

■ Reputation-based approach

□ use reputation as a base for trust

□ closed domains: each has its own method to query, store, aggregate, infer, interpret and represent reputation

□ Used in: – Web communities (e-Markets, blogs, social networks)– Services– Software agents

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Reputation.Interoperability (Semantic Technologies);

Trust Management

Concepts?

■ Reputation Targetusers, movies, products, blog posts, tags, companies, services, software agents, and IP addresses

■ Reputation Model all of the reputation statements, events, and processes for a particular context

■ Reputation Contextthe relevant category for a specific reputation

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Reputation Approach

Concepts?

■ Reputation Targetusers, movies, products, blog posts, tags, companies, services, software agents, and IP addresses

■ Reputation Model all of the reputation statements, events, and processes for a particular context

■ Reputation Contextthe relevant category for a specific reputation

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Reputation Approach

Computation Function

Communication Model

Participants

Resources

Representation Model

Storage

Functionalities and Applications

Where…

5Rep. Approach

Reputation of users

Reputation of services

Reputation of business domains

Reputation of service providers

In Service-oriented Arch.

Social/entertainmentSlashdot

News Online Reputation Systems

Opinion & Activities

Business/Jobs network

E-Markets

…a typical buying decision

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7


8


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Ratings and Reviews

■ After buying, the consumer is asked to give his feedback in two ways:

a) stars ratings

b) by answering a seller-feedback questions with an option of leaving a comment.

■ No obvious distinction -at the rating page- of what exactly being rated or reviewed.

■ In one of our user studies:

Online Markets

65%

35%

Differentiate between 5 Stars and reviews

Did not know, thought maybe product quality

Customer Service


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Ratings in Online Markets

■ Only at the description page (policies)

□ stars rating is an overall rating of the product

□ detailed review page is for the buying experience = reviewing the seller (order fulfillment, customer service, correct item description)

”If your comments include any of the following, your feedback is subject to removal: Product reviews: It is more appropriate to review product on the product detail page....Customers reviews are for products”.§

■ Three reputation attributes:

□ product quality

□ seller reputation

□ customer service

Online Markets


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Our User Studies

■ test

□ how users perceive reputation

□ how many of reputation attributes the users consider

□ which of them the users focus on

□ used in the decision process with each other or separately?

□ their relation to the overall rating


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Online Survey + interviews:

200 users, different countries

Online Chocolate Store + detailed ratings

User Survey:

http://www.kwiksurveys.com?s=ILNING_865460b6

Study 113

http://www.kwiksurveys.com/?s=ILNING_865460b6

User Survey:

http://www.kwiksurveys.com?s=ILNING_865460b6

Study 114

http://www.kwiksurveys.com/?s=ILNING_865460b6

Results

40%

60%

eBay (number, Gold stars)Stars and detailed Reviews

65%

21%

14%

Rating Frequency

Sometimes

Never

other

80%

20%

No. of Reviews

High-Value Stars

40%

60%

No. of Reviews

Detailed rat-ings


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Results

40%

60%

eBay (number, Gold stars)Stars and detailed Reviews

65%

21%

14%

Rating Frequency

Sometimes

Never

other

80%

20%

No. of Reviews

High-Value Stars

40%

60%

No. of Reviews

Detailed rat-ings

50%39%

11%

high seller reputation

conjoint mea-sure of price & quality

Good Customer Service

other


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Results: comparison bet. Rating styles


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Results: comparison bet. Rating styles

no ”reviews” option available users explicitly asked for it to be added stating that this is the only way to gather more information on a provider before selecting him


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What does this mean?Analysis

■ Confusion in interpreting the meaning of

□ rating styles

□ reputation values

■ Reputation of a seller or a product means more than one attribute

□ combination of attributes: neither represented nor clear from current rating methods

■ Detailed ratings were preferred over stars ratings and high number-of-

reviews

■ Users tend to read reviews (comments and feedback) in order to decide on

a product or a seller


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ChocStoreStudy 2

■ Online Chocolate Store

■ For our institution personal

■ Normal Online store functionalities

■ 2 choices of payments

■ 3 choices of delivery

■ prices were changed

significantly compared to

the procurement cost

(underpriced, overpriced)


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Online Chocolate StoreObjectives

■ How many attributes are suitable for a review

■ What is the important aspect of each user’s rating

■ Based on the previous study, we show that several attributes - delivery time

for instance- affects rating

■ To examine categorized ratings with multiple attributes vs. overall ratings


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Online Chocolate StoreResults

■ The overall rating does not always relate to the same attribute (i.e.

delivery, quality, price) -> overall rating does not convey or show the

meaning behind it

■ Delivery time affects delivery rating and sometimes overall rating

■ Prices always affect overall rating

■ Pick one attribute that is most important to your overall rating:

23.00%

38.50%

38.50%

Rating AttributesDeliveryPrice Quality


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What does this mean?Analysis

■ Users gave the same overall rating for different reasons

■ Some cared more about product quality, others cared for how fast the

delivery is

■ Average 4 attributes in the form was acceptable by all users

■ Singular formats of reputation is not enough

■ ignore the reasons and information behind the ratings

■ Users use several pieces of information to decide on a service provider


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So?Discussion

■ A more aware user

■ read textual reviews to find what he/she is looking for

■ Possible -> for human users though time consuming

Not Possible -> in other domains e.g. software agents or web services,

■ text analysis: a highly expensive task that can not be performed for every

transaction

■ A user seeking a provider checks for high reputed ones

■ assuming that the high reputation interprets into his own attribute of

selection


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User

Relying PartyBusiness

Owner/Seller/Factory

E-Shop

Why Rating is not enough? No context

Bad Review

Delivery Service

Delayed Package

Context excluded from the reputation value

□ reputation query is too general

□ 3 different contexts

□ delivery, quality, price


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Single Rating

Why Rating is not enough?

■ Rating “used books”

□ is the rating for the book itself -> the user liked what he read

□ or the quality of the book -> was new and good printing

□ or the service provided by Amazon for example -> offering the book, price, delivery, payment method, etc.


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Different representations, interaction styles and trust rating scales

Different perceptions



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Different representations, interaction styles and trust rating scales

Different perceptions


Isolated reputation communities that have different:

□ perception of reputation

□ calculation of reputation

□ interpretation of reputation

□ overall reputation – not context related


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No portability



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No portability


□ Starting from scratch for each domain□ Cold start problem

□ No reputation information exchange


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No portability


□ Starting from scratch for each domain□ Cold start problem

□ No reputation information exchangeSolutionUnify the representation not the calculation

Define a generic reputation OntologyEmbed more information- relating semanticsFacilitate knowledge exchange


Ontologies

33Why Ontologies?

Ontologies

Concepts & relationships used to describe & represent an area of

knowledge

■ creates a common understanding

■ specifies the factors -their explicit semantics - involved in computing

reputation

■ separates the definition of reputation from how it is calculated

■ enables the mapping between reputation concepts in different models

■ facilitates the use of existing mapping & integration techniques in IS for

reusing reputation info

■ reputation interoperability & cross community sharing of reputation

information


Competency Questions

Q1 Reputation definition define the notion of reputation within the domain?

Q2 Reputation Identity entities? reputation roles such as source, target, evaluator, etc.?

Q3 Reputation representation in a single format? is it enough to express its meaning? how reputation will be represented, communicated?

Q4 Reputation statementa reputation statement? what information does a reputation transaction hold?

Q5 Reputation computation mechanismis there a property that defines and describes the computation mechanism?

34Reputation Requirements


Cont. Competency Questions

35Reputation Requirements

Q6 Reputation contexta property that expresses the relation between a reputation value and the context of its creation? combine its reputation in different contexts?

Q7 Reputation factorsfactors affecting reputation? does the source’s reputation affect reputation calculation?

Q8 Reputation dynamics and temporal effect change through time? properties that reflect the change in reputation values? time validity? is the new value time-stamped?

Q9 Reputation history can we maintain the history of reputation values that an entity owned?

Q10 Reputation expressivenesscan we define and describe the semantics of the involved factors, contexts, relations, and concepts? is there a way to communicate the semantics of a reputation context?


Reputation Object Model

The RO model

■ Uses more information about the domain

□ the contexts and/or relevant quality criteria

■ Using this information, reputation is represented differently

□ as a developed object

■ The Reputation Object profiles an entity’s performance and has knowledge about

□ contexts

□ ratings values/reviews/feedback

□ computation functions

□ collecting method

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Reputation Objecta profile of an entity’s performance

Representation


Reputation Object Ontology

37RO Ontology



38RO Ontology



39RO Ontology



40RO Ontology


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Which Technology?

Semantic Technologies

■ Developing interoperable reputation objects requires

■ structure and standardize reputation info and its relevant data

■ enable data integration

■ provide ways to relate the data to its explicit semantics

Used Technology

■ provide common data representation framework in order

to facilitate the integration of multiple sources to draw new

conclusions


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What is Semantic Web?

■ extension of the current web in which information is given well-defined

meaning, better enabling computers and people to work in cooperation

■ collection of standard technologies to realize a Web of Data where they are

linked & are understandable by machines

■ provide common data representation framework in order to facilitate the

integration of multiple sources to draw new conclusions


■ Goals

■ Standard Representation

■ Linkability and Integration

■ Automation

■ Reuse across applications

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…define and structure Semantic Technologies

Data IntegrationPhases

Define

■Ontologies

Concepts &relationships used to

describe & represent an area of

knowledge

Structure

■RDF

■RDFa, microformats

■OWL

■…

RO Ontology: OWL

44■ Developed using Protégé 3.4.4 OWL-DL

■ Vocabulary of RO Ontology:

■ to represent an entity's (foaf:Agent) reputation

■ an object (ReputationObject) has one or multiple instances of class Criterion or QualityAttribute

■ each criterion instance has a ReputationValue (currentValue and historyList) that has a set of PossibleValues (as literals or resources URI)

■ a criterion is collected by a CollectingAlgorithm & computed using a ComputationAlgorithm

■ Employing also known vocabulary OWL, RDFS, FOAF, XSD, RDF Review, ..

RO Ontology


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Implementation: LibraryRO Ontology

Using Semantic Technologies

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enabling reputation information exchange

facilitate the integration of multiple sources to draw new conclusions,

connecting data to its definitions and to its context

achieving reputation interoperability

Context-aware reputation

ensuring understandability and reusability of the embedded information

Goals



A seller RO in e-Markets

47■ Using GoodRelations ontologies to describe a seller and RO ontology to

describe its reputation

Criterion 1

Applications

Criterion 2


Usage Control in E-Markets

48■ Using ROs for decisions during runtime allows revoking participants due to

their former behavior

■ Security settings is one of the RO criteria

Applications


Rule-based Reputation Systems

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■ Using Rule Responder (Multi Agent Reasoning system) to deploy distributed rule inference services

■ Agents/services communicate reputation objects or specific measures in them

■ Reputation values used in the agent’s rule logic,

o e.g. deciding on a seller based on delivery method and review

Applications


Cloud Provider Selection

50■ Selecting cloud providers based on their reputation & a consumer preference

list

■ Reducing the risks by selecting reputable SPs

From the detailed reputation profile,

□ cross reference the quality parameters requested by the consumer and the performance parameters extracted from the providers’ reputation objects.


Applications

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Personalized News Network

■ Real Experience We want to stay informed with real trusted news Online Social Network was the answer

■ 2 motivating facts: Delayed news in the mainstream media Fabricated news


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Personalized News Network

■ Real Experience We want to stay informed with real trusted news Online Social Network was the answer

■ 2 motivating facts: Delayed news in the mainstream media Fabricated news

■ Filtered□ Trends□ Trusted networks


Thank You

Rehab Alnemr

([email protected])

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Business

real cognitive

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ratings style

ratings style

software agents