The well tempered search application

The Well-Tempered Search
Application
Variations on a Theme:
Why does my search app suck, and
what can I do about it?
Ted Sullivan – (old Phuddy Duddy)
Senior (very much so I’m afraid) Solutions (I hope) Architect (and sometime plumber)
Lucidworks Technical Services

Our Basic Premises (Premisi?)
• Lemma 1: Search Applications use algorithms that make
finding chunks of text within large datasets possible in
HTT (human-tolerable time).
• Lemma 2: These algorithms work by breaking text into
primitive components and building up a search
“experience” from that.
• Lemma 3: Lemma 2 is not sufficient to achieve Lemma 1.

The Basic Disconnect
• Text can be analyzed at the level of tokens
(syntax) and at the level of meaning
(semantics).
• We think one way (semantics), search engines
think another (syntax – i.e. token order).
• How do we bridge the gap? … More clever
algorithms!

Art and Science
• We need to be intelligent curators of these
algorithms. Craftsmen (craftswomen?) that
think of these as tools with a specific purpose.
• Like any good craftsperson – we need a wide
array of tools to get the job done (well
almost).

When is my search app done?
• Quick answer: NEVER (ain’t consultin’ great?)
• Long answer – As long as it is continues to
improve, like fine wine or bourbon, you are on
the path to enlightenment.
• How do you get there grasshopper? Add
semantic intelligence to the engine!

Search cannot be shrink-wrapped!!
What have we got for Donny behind Curtain #1 Jay?
Well Monty - Heeeeeeeeeeeerrrrrrrreeeeesssss the
Google … SEARCH Appliance!!!!

Search cannot be shrink-wrapped!!
What have we got for Donny behind Curtain #1 Jay?
Well Monty - Heeeeeeeeeeeerrrrrrrreeeeesssss the
Google … SEARCH Appliance!!!!*
Sorry Donny – It’s a ZONK!
* but Google Web Search has some Serious Mojo!

Prelude part 1– The basic problem
The inverted index and “bag-of-words” search:
The red fox jumped over the fence.
Time flies like an arrow. Fruit flies like a banana.
the 1,6
red 2
fox 3
jumped 4
over 5
fence 7
flies 2,7
like 3,8

Prelude part B – The Tried and True
• Phrase and Proximity boosting and “Slop”
• Synonyms and stop words
• Stemming or Lemmatization
• Autocomplete
• Best Bets / Landing Pages – the
sledgehammer
• Spell check – spell suggest – aka the warm
fuzzies.

Fugue - Subject or Exposition
Search engines need more ‘semantic
awareness’ or at least the illusion of this.
There is a heavy duty solution called Artificial
Intelligence – which except in the fertile
imagination of Hollywood screenwriters, is not
there yet. So we need to fake it just a bit.

Theme and Variations I
autophrasing and the red sofa
Theme: When multiple words mean just one thing.
Fuzzy way: Boosting phrases (proximity and phrase slop)
- pushes false positives down – i.e. out of the limelight
- i.e. - shoves ‘em under the rug
This encounters a problem with faceted search
Like the eye of Sauron in LOTR or Santa Claus, the faceting engine SEES
ALL (sins)!
Brake Pads example: hit on things that have ‘brake’ (like children’s stroller
brakes) and ‘pads’ – like mattress pads.

Variation I: Autophrasing
AutophrasingTokenFilter tells Lucene not to
tokenize when a noun phrase represents a single
thing - by providing a flat list of phrases.
Creates one-to-one token mapping that Lucene
prefers because it avoids the “sausagization”
problem.
https://github.com/LucidWorks/auto-phrase-tokenfilter

income tax refund
income tax
tax refund
“income tax” is not income.
A “tax refund” is not a tax.
Solution: Autophrasing + synonym mapping
income tax => tax
tax refund => refund
Autophrasing Example

Autophrasing Setup
autophrases.txt:
income tax
tax refund
tax rebate
sales tax
property tax
synonyms.txt
income_tax,property_tax,sales_tax,tax
tax_refund,refund,rebate,tax_rebate
<fieldType name="text_autophrase" class="solr.TextField" positionIncrementGap="100">
<analyzer type="index">
<tokenizer class="solr.StandardTokenizerFactory"/>
<filter class="solr.LowerCaseFilterFactory"/>
<filter class="com.lucidworks.analysis.AutoPhrasingTokenFilterFactory"
phrases="autophrases.txt"
includeTokens="true” replaceWhitespaceWith="_" />
<filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords.txt"
enablePositionIncrements="true" />
<filter class="solr.PorterStemFilterFactory"/>
</analyzer>
</fieldType>

Multi-term synonym problem
• New York, New York – it’s a HELLOVA town!
Subject was inspired by an old JIRA ticket: Lucene-1622
“if multi-word synonyms are indexed together with the
original token stream (at overlapping positions), then a query
for a partial synonym sequence (e.g., “big” in the synonym
“big apple” for “new york city”) causes the document to
match”
(or “apple” which will hit on my blog post if you crawl
lucidworks.com !)

This means certain phrase queries should match but don't (e.g.: "hotspot
is down"), and other phrase queries shouldn't match but do (e.g.: "fast
hotspot fi").
Other cases do work correctly (e.g.: "fast hotspot"). We refer to this
"lossy serialization" as sausagization, because the incoming graph is
unexpectedly turned from a correct word lattice into an incorrect
sausage.
This limitation is challenging to fix: it requires changing the index format
(and Codec APIs) to store an additional int position length per position,
and then fixing positional queries to respect this value.
Sausagization: from Mike McCandless blog Changing Bits:
Lucene's TokenStreams are actually graphs!
http://blog.mikemccandless.com/2012/04/lucenes-tokenstreams-are-actually.html

Multi-term synonym demo
new york
new york state
empire state
new york city
new york new york
big apple
ny ny
city of new york
state of new york
ny state
autophrases.txt
new_york => new_york_state,new_york_city,big_apple,
new_york_new_york,ny_ny,nyc,empire_state,ny_state,
state_of_new_york
new_york_state,empire_state,ny_state,
state_of_new_york
new_york_city,big_apple,new_york_new_york,ny_ny,nyc,
city_of_new_york
synonyms.txt

This document is about new york state.
This document is about new york city.
There is a lot going on in NYC.
I heart the big apple.
The empire state is a great state.
New York, New York is a hellova town.
I am a native of the great state of New York.
new york new york city new york state
/select /autophrase

This document is about new york state.
This document is about new york city.
There is a lot going on in NYC.
I heart the big apple.
The empire state is a great state.
New York, New York is a hellova town.
I am a native of the great state of New York.
empire state
/select /autophrase
(Even a blind squirrel finds a nut once in a while)

Variation II: The Red Sofa Problem
{
"response":{"numFound":3,"start":0,"docs":[
{
"color":"red",
”text":"This is the red sofa example. Please find with 'red sofa' query.",
{
"color":"red",
”text":"This is a red beach ball. It is red in color but is not something that you
should not sit on because you would tend to roll off.",
{
"color":"blue",
”text":"This is a blue sofa, it should only hit on sofas that are blue in color."]
}}
OOTB – q=red sofa is interpreted as text:red text:sofa (default OR)
http://localhost:8983/solr/collection1/select?q=red+sofa&wt=json

Closing the Loop:
Content Tagging and Intelligent Query Filtering
Using the search index itself as the knowledge source:

Solution for the Red Sofa problem
Query Autofiltering: Search Index driven query introspection /
query rewriting:

Lucene FieldCache Magic
Lucene FieldCache (to be renamed UninvertedIndex in Lucene 5.0)
Inverted Index:
Show all documents that have this term value in this field.
Uninverted or Forward Index:
Show all term values that have been indexed in this field.
SolrIndexSearcher searcher = rb.req.getSearcher();
SortedDocValues fieldValues = FieldCache.DEFAULT.getTermsIndex(
searcher.getAtomicReader( ), categoryField );
…
StringTokenizer strtok = new StringTokenizer ( query, " .,:;"'" );
while (strtok.hasMoreTokens( ) ) {
String tok = strtok.nextToken( ).toLowerCase( );
BytesRef key = new BytesRef( tok.getBytes() );
if (fieldValues.lookupTerm( key ) >= 0) {

Query Autofiltering
{
"response":{"numFound":1,"start":0,"docs":[
{
"id":"1",
"color":"red",
"description":"This is the red sofa example. Please find with 'red sofa' query."]
}
http://localhost:8983/solr/collection1/infer?q=red+sofa&wt=json
Now search for “red sofa” only returns ….. red sofas!
But – is this too “brute force”? The takeaway is that using
the search index AS a knowledge store can be very powerful!

Architecture: its all about Plumbing
• Pipelines for every occasion.
Indexing Pipelines – good ‘ole ETL
- Content enrichment, tagging
- Metadata cleanup
Query Pipelines
– identification, query preprocessing
- introspection
One is the “hand” the other, the “glove”

Index Pipelines
Lots of choices here:
• Internal to Solr – DIH, UpdateRequestProcessor
Pros and cons
• External – Morphlines, Open Pipeline, Flume,
Spark, Hadoop, Custom SolrJ
• Lucidworks Fusion

Entity and Fact Extraction
Entities:
Things, Locations, Dates, People, Organizations, Concepts
Entity Relationships
Company was acquired by Company
Drug cures Disease
Person likes Pizza
Annotation Pipelines (UIMA, Lucidworks Fusion):
Entity Extraction followed by Fact Extraction
Pattern method:
$Drug is used to treat $Condition
Parts of Speech (POS) analysis
Subject Predicate Object

Theme and Variations II
The Classification Wars
• Machine Learning or Taxonomy – is it a Floor
Wax or a Dessert Topping?
Answer: It’s a floor wax AND a dessert topping! Its delicious and just look at that shine!

Machine Learning
Use mathematical vector-crunching algorithms like Latent
Dirichlet Allocation (LDA), Bayesian Inference, Maximum
Entropy, log likelihood, Support Vector Machines (SVM) etc., to
find patterns and to associate those patterns with concepts.
Can be supervised (i.e. given a training set) or unsupervised (the
algorithm just finds clusters). Supervised learning are called
semi-automatic classifiers.
Check out Taming Text by Ingersoll, Morton and
Farris (Manning)

Machine Learning In
LucidworksFusion
Training Data
NLP Trainer
Stage
NLP Model
Test Data
NLP Classifier
Stage
Classified
Documents

Taxonomy or Ontology
“Knowledge graphs” that relate things and concepts to each other
either hierarchically or associatively.
Pros:
Works without large amounts of content to analyze
Encapsulates the knowledge of human subject matter experts
Cons:
Often not well designed for search (mixes semantic relationship
types / organizational logic)
Requires curation by subject matter experts whose time is costly

Taxonomies Designed for Search
Category nodes and Evidence nodes
Category Node:
A ‘parent’ node
Can have child nodes that are:
Sub Categories
Evidence Nodes
Evidence Node:
Tends to be a leaf node (no children)
Contains keyterms (synonyms)
May contain “rules” e.g. (if contains term a and term b but not term c)
Evidence Nodes can have more than one category node parent
Hits on Evidence Nodes add to the cumulative score of a Category Node.
Scores can be diluted as the accumulate up the hierarchy – so that the
nearest category gets the strongest ‘vote’.

US Corporations
Foreign Corporations
British
Chinese
French
German
Japanese
Russian
etc.
Fortune 100 Companies
Energy
Financial Services
Investment Banks
Commercial Banks
Health Care
Health Insurance
HMO
Medical Devices
Pharmaceuticals
Hospitality
Manufacturing
Aircraft
Automobiles
Electrical Equipment

Ford, GM, Chrysler
Energy
Financial Services
Investment Banks
Commercial Banks
Health Care
Health Insurance
HMO
Medical Devices
Pharmaceuticals
Hospitality
Manufacturing
Aircraft
Automobiles
US Corporations
British
Chinese
French
German
Japanese
Russian
etc.

Ford, GM, Chrysler,Toyota,BMW
Energy
Financial Services
Investment Banks
Commercial Banks
Health Care
Health Insurance
HMO
Medical Devices
Pharmaceuticals
Hospitality
Manufacturing
Aircraft
Automobiles
US Corporations
British
Chinese
French
German
Japanese
Russian
etc.

Energy
Financial Services
Investment Banks
Commercial Banks
Health Care
Health Insurance
HMO
Medical Devices
Pharmaceuticals
Hospitality
Manufacturing
Aircraft
Automobiles
GE, Boeing
US Corporations
British
Chinese
French
German
Japanese
Russian
etc.

Energy
Financial Services
Investment Banks
Commercial Banks
Health Care
Health Insurance
HMO
Medical Devices
Pharmaceuticals
Hospitality
Manufacturing
Aircraft
Automobiles
GE, Boeing
Bank of America, Hyatt
US Corporations
British
Chinese
French
German
Japanese
Russian
etc.

Query Pipelines
The ‘Wh’ Words: Who, What, When, Where
Who are they (authentication)?
What can they see (security - authorization)?
When can they see it (entitlement)?
What are they interested in (personalization / recommendation)?
Where are they now (location)?

Query Pipelines
Inferential Search
Query introspection -> Query modification.
Query Autofiltering
Are you feeling lucky today?
Topic boosting / spotlighting
Use ML to detect the topic, then boost and/or spotlight
results tagged this way.
Use a specialized collection to store ‘facet knowledge’

The Art of the Fugue:
Inferential Search
• Infer what the user is looking for and give them
that
• Clever software infers meaning aka query
“intent”
• When we do this right, it appears to be magic!

Machine Learning Drives
Query Introspection
Training Data
NLP Trainer
Stage
NLP Model
Test Data
NLP Classifier
Stage
Classified
Documents

Machine Learning models can drive
Query Introspection
NL Query
NLP Query
Stage
NLP Model
Tagged
Query
Landing
Page
Boost
Documents

Da Capo al Coda
• Killer search apps are crafted from fine
ingredients and like fine whiskey will get
better with age - if you are paying attention to
‘what’ your users are looking for.
• Putting the pieces together requires an
understanding of ‘what’ things, independent
of what words they use to describe it.

Thanks for your attention!
Ted Sullivan
Lucidworks, Technical Services
ted.sullivan@lucidworks.com
Skype: ted.sullivan5
LinkedIn
Metuchen, New Jersey
(You gotta problem with that?)

The well tempered search application

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