Facets Berkeley

8/8/2019 Facets Berkeley

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Semi-Automated Creation of

Facet Hierarchies

Marti HearstSchool of Information, UC Berkeley

Joint work with Dr. Emilia Stoica


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Marti Hearst, Taxonomy Bootcamp 06

Outline

Faceted Metadata Definition

Advantages

Flamenco:

Search Interface Design using Faceted Metadata

Castanet: (Semi) Automated Tool for Creation of Category Systems

Comparison to State-of-the-Art Alternatives

Conclusions


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Focus: Search and Navigationof Large Collections

Image

Collections

E-Government

Sites

Shopping Sites

Digital Libraries


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Study by Vividence in 2001 on 69 Sites 70% eCommerce

31% Service

21% Content

2% Community

Poorly organized search results Frustration and wasted time

Poor information architecture Confusion

Dead ends

"back and forthing"

Forced to search

Problems with Site Search


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What we want to Achieve

Integrate browsing and searching seamlessly

Support exploration and learning

Avoid dead-ends, pogoing, and lostness


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Main Idea

Use hierarchical faceted metadata Design the interface to:

Allow flexible navigation

Provide previews of next steps

Organize results in a meaningful way

Support both expanding and refining the search


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The Problem With Hierarchy

Most things can be classified in more than one way.

Most organizational systems do not handle this well.

Example: Animal Classification

otter

penguin

robin

salmon

wolf

cobra

bat

Skin

Covering

Locomotion

Diet

robin

bat wolf

penguin

otter, sealsalmon

robin

bat

salmon

wolf

cobra

otter

penguin

seal

robin

penguinsalmon

cobra

bat

otter

wolf


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Inflexible Force the user to start with a particular category

What if I dont know the animals diet, but theinterface makes me start with that category?

Wasteful Have to repeat combinations of categories

Makes for extra clicking and extra coding

Difficult to modify To add a new category type, must duplicate it

everywhere or change things everywhere

The Problem with Hierarchy


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The Problem With Hierarchy

start

fur scales feathers

swim fly run slither

fur scales feathers fur scales feathers

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

fish

rodents

insects

salmon bat robin wolf


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The Idea of Facets

Facets are a way of labeling data A kind of Metadata (data about data)

Can be thought of as properties of items

Facets vs. Categories Items are placed INTO a category system

Multiple facet labels are ASSIGNED TO items


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The Idea of Facets

Create INDEPENDENT categories (facets) Each facet has labels (sometimes arranged in a hierarchy)

Assign labels from the facets to every item Example: recipe collection

Course

Main Course

Cooking

Method

Stir-fry

Cuisine

Thai

Ingredient

Bell Pepper

Curry

Chicken


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The Idea of Facets

Break out all the important concepts into theirown facets

Sometimes the facets are hierarchical Assign labels to items from any level of the hierarchy

Preparation Method

Fry

Saute

Boil

BakeBroil

Freeze

Desserts

Cakes

Cookies

Dairy

Ice CreamSorbet

Flan

Fruits

Cherries

Berries

Blueberries

StrawberriesBananas

Pineapple


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Using Facets

Now there are multiple ways to get to each item

Preparation Method

Fry

SauteBoil

Bake

Broil

Freeze

Desserts

Cakes

CookiesDairy

Ice Cream

Sherbet

Flan

Fruits

Cherries

BerriesBlueberries

Strawberries

Bananas

Pineapple

Fruit > Pineapple

Dessert > Cake

Preparation > Bake

Dessert > Dairy > Sherbet

Fruit > Berries > Strawberries

Preparation > Freeze


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Example:

Nobel Prize Winners Collection(Before and After Facets)


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Only One Way to View Laureates


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First, Choose Prize Type


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Next, view the list!

The user must first choose an

Award type (literature), then browse

through the laureates in

chronological order.

No choice is given to, say organize

by year and then award, or by

country, then decade, then award, etc.


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Flamenco Interface:Using Hierarchical Faceted Metadata

O i Vi


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Opening ViewSelect literature from PRIZE facet


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Group results by YEAR facet


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Select 1920s from YEAR facet

C t i PRIZE lit t AND


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Current query is PRIZE > literature ANDYEAR: 1920s. Now remove PRIZE > literature


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Now Group By YEAR > 1920s

Hi h T l


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Hierarchy Traversal:Group By YEAR > 1920s, and drill down to 1921


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Select an individual item


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Use Endgame to expand out


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Use Endgame to expand out


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Or use More like this to find similar items


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Start a new search using keyword California


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Note that category structure remains after the keyword search

h i k d A d i h f bhi h


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The query is now a keyword ANDed with a facet subhierarchy


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Using Facets

The system only shows the labels that correspondto the current set of items Start with all items and all facets

The user then selects a label within a facet

This reduces the set of items (only those that havebeen assigned to the subcategory label are displayed)

This also eliminates some subcategories from the view.


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Advantages of Facets

Cant end up with empty results sets (except with keyword search)

Helps avoid feelings of being lost. Easier to explore the collection.

Helps users infer what kinds of things are in thecollection. Evokes a feeling of browsing the shelves

Is preferred over standard search for collection

browsing in usability studies. (Interface must be designed properly)


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Advantages of Facets

Seamless to add new facets and subcategories Seamless to add new items.

Helps with categorization wars Dont have to agree exactly where to place something

Interaction can be implemented using a standardrelational database.

May be easier for automatic categorization


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Information previews

Use the metadata to show where to go next More flexible than canned hyperlinks

Less complex than full search

Help users see and return to previous steps

Reduces mental work Recognition over recall

Suggests alternatives

More clicks are ok only if(J. Spool) The scent of the target does not weaken

If users feel they are going towards, rather than away, from their

target.


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Facets vs. Hierarchy

Early Flamenco studies compared allowingmultiple hierarchical facets vs. just one facet.

Multiple facets was preferred and more successful.


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Limitation of Facets

Do not naturally capture MAIN THEMES

Facets do not show RELATIONS explicitly

Aquamarine

Red

Orange

Door

Doorway

Wall

Which color associated with which object?

Photo by J. Hearst, jhearst.typepad.com


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Terminology Clarification

Facets vs. Attributes Facets are shown independently in the interface Attributes just associated with individual items

E.g., ID number, Source, Affiliation

However, can always convert an attribute to a facet

Facets vs. Labels Labels are the names used within facets

These are organized into subhierarchies

Synonyms There should be alternate names for the category labels

Currently (in Flamenco) this is done with subcategories

E.g., Deer has subcategories stag, fawn, doe


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Usability Study Results


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Flamenco Usability Studies

Usability studies done on 3 collections: Recipes (epicurious): 13,000 items Architecture Images: 40,000 items Fine Arts Images: 35,000 items

Conclusions: Users like and are successful with the dynamic

faceted hierarchical metadata, especially forbrowsing tasks

Very positive results, in contrast with studies onearlier iterations.


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Most Recent Usability Study

Participants & Collection 32 Art History Students ~35,000 images from SF Fine Arts Museum

Study Design Within-subjects

Each participant sees both interfaces Balanced in terms of order and tasks

Participants assess each interface after use Afterwards they compare them directly

Data recorded in behavior logs, server logs, paper-surveys; one or

two experienced testers at each trial. Used 9 point Likert scales. Session took about 1.5 hours; pay was $15/hour


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Post-Interface Assessments

All significant at p


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Post-Test Comparison

15 16

2 30

1 29

4 28

8 23

6 24

28 3

1 31

2 29

FacetedBaseline

Overall Assessment

More useful for your tasks

Easiest to use

Most flexible

More likely to result in dead ends

Helped you learn more

Overall preference

Find images of roses

Find all works from a given period

Find pictures by 2 artists in same media

Which Interface Preferable For:


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How to Create Facet Hierarchies?

Our Approach: Castanet


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Example: Recipes (3500 docs)


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Castanet Output (shown in Flamenco)

h l


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C O ( h i Fl )


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C O ( h i Fl )


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C O ( h i Fl )


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Our Approach:


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Our Approach:Leverage the structure of WordNet

O A h


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Our Approach

Leverage the structure of WordNet

Docum

ents

WordNet

Get

hypernym

pathsSelect

terms

Build

treeCompress

tree

Divide into facets


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1. Select Terms

red blue

Select well distributed

terms from collection Documen

ts

WordNet

Get

hypernym

pathsSelectterms

Build

tree

Comp.

tree

h


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2. Get Hypernym Path

red blue

chromatic color

abstraction

property

visual property

color

red, redness

abstraction

property

visual property

color

blue, blueness

chromatic color

Documen

ts

WordNet

Get

hypernym

pathsSelectterms

Build

tree

Comp.

tree


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3. Build Tree

red blue

chromatic color

abstraction

property

visual property

color

red, redness

abstraction

property

visual property

color

blue, blueness

chromatic color

red blue

abstraction

property

visual property

color

red, redness

chromatic color

blue, blueness

Documen

ts

WordNet

Get

hypernym

pathsSelectter

ms

Build

tree

Comp.

tree

4 Compress Tree


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4. Compress Tree

Documen

ts

WordNet

Get

hypernym

pathsSelectter

ms

Build

tree

Comp.

tree

red, redness

color

red

chromatic color

blue, blueness

blue

green, greenness

greengreenred

color

chromatic color

blue

4 Compress Tree (cont )


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4. Compress Tree (cont.)

red

color

chromatic color

blue green

color

red blue green

Documen

ts

WordNet

Get

hypernym

pathsSelectter

ms

Build

tree

Comp.

tree

5 Divide into Facets


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5. Divide into Facets

Divide into facets

Disambiguation


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Disambiguation

Ambiguity in: Word senses

Paths up the hypernym tree

Sense 1 for word tuna

organism, being

=> plant, flora=> vascular plant

=> succulent

=> cactus

=> tuna

Sense 2 for word tuna

organism, being

=> fish=> food fish

=> tuna

=> bony fish

=> spiny-finned fish

=> percoid fish

=> tuna

2 paths for same word

2 paths for

same sense

How to Select the Right Senses and Paths?


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How to Select the Right Senses and Paths?

First: build core tree (1) Create paths for words with only one sense

(2) Use Domains Wordnet has 212 Domains

medicine, mathematics, biology, chemistry, linguistics, soccer, etc.

Automatically scan the collection to see which domains apply

The user selects which of the suggested domains to use or may add own

Paths for terms that match the selected domains are added to the coretree

Then: add remaining terms to the core tree.


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Castanet Evaluation

Castanet Evaluation


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Castanet Evaluation

This is a tool for information architects, so peopleof this type did the evaluation

We compared output on Recipes

Biomedical journal titles

We compared to two state-of-the-art algorithms LDA (Blei et al. 04)

Subsumption (Sanderson & Croft 99)

Subsumption Output (shown in Flamenco)


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LDA Output (shown in Flamenco)


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Evaluation Method


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Evaluation Method

Information architects assessed the categorysystems

For each of 2 systems output: Examined and commented on top-level

Examined and commented on two sub-levels

Then comment on overall properties Meaningful?

Systematic? Likely to use in your work?

Evaluation Results


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Evaluation Results

Results on recipes collection for Would you usethis system in your work? Yes in some cases or yes definitely:

Pine (Castanet): 29/34

Oak (LDA): 0/18 Birch (Subsumption): 6/16

Results on quality of categories:

Opportunities for Tagging


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Opportunities for Tagging

New opportunity: Tagging, folksonomies (flickr de.lici.ous)

People are created facets in a decentralized manner

They are assigning multiple facets to items

This is done on a massive scale This leads naturally to meaningful associations

Conclusions


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Conclusions

Flexible application of hierarchical faceted metadata is aproven approach for navigating large informationcollections.

Midway in complexity between simple hierarchies and deepknowledge representation.

Currently in use on e-commerce sites; spreading to other domains

Systems are needed to help create faceted metadatastructures

Our WordNet-based algorithm, while not perfect, seems like itwill be a useful tool for Information Architects.


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For more information:

flamenco.berkeley.edu

Thank you!

Marti Hearst & Emilia Stoica

Facets Berkeley

Documents

Transcript of Facets Berkeley