Social media mining hicss 46 part 2

Mining and Analyzing Social Media: Part 2Dave King

January 7, 2013

Copyright 2011 JDA Software Group, Inc. - CONFIDENTIAL

Agenda: Part 2

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• Sentiment Analysis & Opinion Mining • Defined• Business Interest & Software Packages• Levels of Analysis• Automated Classification

• Social Network Analysis• Defined• History• Basic techniques and measures• Ego and Social-Centric Analysis


Sentiment Analysis and Opinion Mining:Interchangeable Terms

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Computational study of opinions, sentiments, subjectivity, evaluations, attitudes, appraisals, affects, views, emotions, etc., expressed in text. (Lui, 2012)


Products

Issues and Focus

Sentiment Analysis and Opinion Mining:Business Interests

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Marketing

Message

Service

Response

Company


Opinion Mining and Sentiment Analysis:Some Sample Questions of Interest

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• Is the sentiment towards my X primarily positive, neutral, or negative? How does it compare to my key competitors? Has it changed overtime?

• What factors are positively and negatively influencing my X’s image?

• Are there opportunities and needs my customers are identifying for me through their conversations?


Opinion Mining and Sentiment Analysis:An Offshoot of Social CRM

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Social CRM • Social Media services,

techniques and technology for engaging customers

• Sometimes synonymous with Social Media Monitoring

• Gartner’s Magic Quadrant has a min of $10M in rev.



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Sentiment Analysis and Opinion Mining:Commercial Products – General Operation

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Sentiment Analysis and Opinion Mining:Some Examples – What do you see?

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Sentiment Analysis and Opinion Mining:

What do you see?

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• Opinion holders: persons who hold the opinions• Opinion targets: entities and their features/aspects• Sentiments: positive and negative• Time: when opinions are expressed


Sentiment Analysis and Opinion Mining:Opinion Defined

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Simply a positive or negative sentiment, view, attitude, emotion, or appraisal about an entity or an aspect of the entity from an opinion holder at a particular point in time.

• Opinion is a quintuple (ej, ajk, soijkl, hi, tl)• Sentiment orientation (“so”): +, -, or possibly neutral


Sentiment Analysis and Opinion Mining:Level of Analysis

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• Document Level: +, -, or 0*• Sentence Level: +, -, or 0*• Entity and Feature/Aspect Level: +, -, or 0*

0* ~ possibly neutral


Sentiment Analysis and Opinion Mining:Example – Document Sentiment Classification

• Basically a Text Classification Problem• Assumptions

–Each document written by single person –About single entity–Goal: discover (_,_,so,_,_)

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15

+

-

Collection of Text Docs

AutomatedClassification

??? Small Set ofPredetermined

SentimentCategories

Doc-TermMatrix*

UnsupervisedSupervised



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DocumentConsolidation

Corpus Refinement(Token, Stem, Stop…)

Establish theCorpus

Feature Selection & Weighting

Doc-TermMatrix

Real-WorldReviews with known sentiment

TestTrain Validate

Classification Algorithm??

- +

Reviews with known Classification

Training Process



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• Naïve Bayes• Support Vector Machine• Decision Trees• Nearest Neighbor (k-NN)• Neural Nets (e.g. SOM)• …

Supervised Classification Algorithms


Sentiment Analysis:Doing Simple Sentiment Analysis

P(H/D) = P(D/H) * P(H)/P(D)H is the hypothesis and D is the data

P(H) is the prior probability of H: the probability that H is correct before the data D are seen

P(D/H) is the conditional probability of seeing the data D given that the hypothesis H is true. This conditional probability is called the likelihood.

P(D) is the marginal probability of D.

P(H/D) is the posterior probability: the probability that the hypothesis is true, given the data and the previous state of belief about the hypothesis.

Thomas Bayes



Confusion Matrix

Accuracy = (TP + TN)/NRecall = TP / (TP + FN)Precision = TP / (TP + FP)Error = (FP + FN)/NF1 = 2*Recall*Precision/(Recall + Precision)

Where N = TP+FP+FN+TN

How do you know if your model works?Depends on your Goal?


Sentiment Analysis:Summary

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• From one type to the next (classification, features, comparisons), it becomes more complex to extract the information.

• Once extracted, standard text mining techniques can be used to classify and compare the opinions

• Simple techniques (like naïve Bayesian) often produce strong results (e.g. 80+% accuracy)


Sentiment Analysis:Comparing Techniques

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Baselines and Bigrams: Simple, Good Sentiment and Topic ClassificationWang and Manning


What do they have in common?

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Here’s a hint

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…and the answer is their Erdos-Bacon Number equals

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6 +5+1

3+3

4+2

=2.957

4.65


Suppose I started with this. What would you have guessed?

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6


Six Degrees of Separation

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6

John Guare

Frigyes Karinthy Stanley Milgram

Duncan Watts

1929 1967

1990 1998


Six Degrees of Separation

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A fascinating game grew out of this discussion. One of us suggested performing the following experiment to prove that the population of the Earth is closer together now than they have ever been before. We should select any person from the 1.5 billion inhabitants of the Earth—anyone, anywhere at all. He bet us that, using no more than five individuals, one of whom is a personal acquaintance, he could contact the selected individual using nothing except the network of personal acquaintances.

Frigyes Karninthy , Chains, 1929

A 1 2 3 4 5

Degrees of separation ~ average path length ~ distance


Social Network AnalysisDefinitions

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Network – Collection of things and their relationships to one another.

Social Network – Collection of humans, roles, groups, and/or institutions and their relationships with one another.

Social Network Analysis (SNA) – Application of Graph Theory or Network Science to the study of social relationships and connections.


Social Network AnalysisMain Purpose

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Detecting and interpreting patterns of social ties among actors. A pattern is meaningful if it expresses:

• Choices by social actors

• Impact of the social system on actors’ behaviors and attitudes


Social Network Analysis:Brief Highlights

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Social Network Analysis:Early Efforts

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Social Network Analysis:Visualization/Analysis Libraries

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© 1973


Social Network Analysis:Growing Interest

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“Ten years ago, the field of Social Network Analysis was a scientific backwater. We were the misfits, rejected from both mainstream sociology and mainstream computer science… The advent of the Social Internet changed everything.”



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… the availability of massive amounts of data in an online setting has given a new impetus towards a scientifically and statistically robust study of the field of social networks



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N=26 N=80

N~90KN~3.5K

N~1400

N=20M

N = 721M

Dining Table Partners World Trade US Political Blogs

Russian LiveJournal Egyptian Revolution Mobile Phones

Facebook Friends


Social Network Analysis:Types of Structural Analysis

• Social Influence Analysis• Expert Discovery• Node Classification• Link Prediction• Community, Subgroup & Clique

Detection in Social Networks• Evolution in dynamic Social Networks• Statistical Analysis and Comparison –

Small Worlds, Weak Ties, and Random Models

• Visualization

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Social Network Analysis:Introduction

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Social Network Analysis:Key Elements

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Graph or NetworkThe set of vertices/nodes, edges/links and the relationship/function connecting them.

A

B

C

D

Graph[ V,E, f ]

Vertex(Node)

Edge(Link)

Vertices or Nodes The “things”

Edges or LinksThe “relationships”


Social Network Analysis:Alternative Representations

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Graph EdgeList

AdjacencyMatrix


Social Network Analysis:Types of Edges or Links

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Undirected,Unweighted

A B

C

Facebook Friends

Undirected,Weighted

A B

C

Facebook Friends

A B

C

TwitterFollowers

Directed,Unweighted

A B

C

EmailNetwork

Directed, Weighted100

6070

20

5

10


Social Network Analysis:Alternative Representations

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Graph EdgeList

AdjacencyMatrix


Social Network Analysis:Types of Networks & Approaches

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Socio-centered Approach“Whole” Network

P6

P5P4

P1

P2 P3

Ego-Centered Approach“Ego-Network”

P5P4

P1

P2 P3

Ego Alters

Vertex (Ego), Neighbors (Alters) &all lines among the Neighbors


Social Network Analysis:Centrality – Who is key?

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Measure Definition Interpretation ReasoningDegree Number of edges or links. In

degree- links in, Out-degree - links out

How connected is a node? How many people can this person reach directly?

Higher probability of receiving and transmitting information flows in the network. Nodes considered to have influence over larger number of nodes and or are capable of communicating quickly with the nodes in their neighborhood.

Betweenness Number of times node or vertex lies on shortest path between 2 nodes divided by number of all the shortest paths

How important is a node in terms of connecting other nodes? How likely is this person to be the most direct route between two people in the network?

Degree to which node controls flow of information in the network. Those with high betweenness function as brokers. Useful where a network is vulnerable.

Closeness 1 over the average distance between a node and every other node in the network

How easily can a node reach other nodes? How fast can this person reach everyone in the network?

Measure of reach. Importance based on how close a node is located with respect to every other node in the network. Nodes able to reach most or be reached by most all other nodes in the network through geodesic paths.

Eigenvector Proporational to the sum of the eigenvector centralities of all the nodes directly connected to it.

How important, central, or influential are a node’s neighbors? How well is this person connected to other well-connected people?

Evaluates a player's popularity. Identifies centers of large cliques. Node with more connections to higher scoring nodes is more important.


Social Network Analysis:Centrality – Who is most important?

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Eigen

Deg

Close

Betw

A

B E

GD

FC

H

RI N

P

KO

J

ML

Q

S


Social Network Analysis:Cohesion – Overall structure

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Social Network Analysis:Cohesion – How well connected?

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A

B E

GD

FC

H

RI N

P

KO

J

ML

Q

S


Social Network Analysis:Ego Centered – Simple Example

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http://apps.facebook.com/touchgraph/


Social Network Analysis:Ego Centered – Another Example

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Social Network Analysis:Ego-Centered – Simple Example

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Social Network Analysis:Ego Analysis – Simple Example

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Netvizz7.0 .gdf (GUESS) file format


Social Network Analysis:Some Analytical Alternatives

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NodeXL

SocVNet

GephiGUESS NetViz

Pajek UCINet/NetDraw Visone

Visual/Analytical Packages



• igraph (R, Python, C): Creating and manipulating graphs

• libSNA (Python): Open-source library for social network analysis (2008 last update)

• NetworkX (Python): Package for complex networks• SNA (R): Social Network Analysis tools

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Visual/Analytical Libraries/Modules



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N = 67 L = 235



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PL = N(N-1)/2 = 2211 Ego Density = L/PL = 235/2211 =.11

Males=76%

FurthestDistance

PowerLaw?

Skewed

StrongWithinClusters

Weak.11Overall


Social Network Analysis:Large Scale Networks

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The emergence of online social networking services over the past decade has revolutionized how social scientists study the structure of human … previously invisible social structures are being captured at tremendous scale and with unprecedented detail.

Accessed within 28 days of May ’11At least one friend

Over 13 years of age


Social Network Analysis:Large Scale Networks

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14% for 100

Assortativity P(F|F) = .52P(F|M) = .51


Social Network Analysis:Is it a Small World after all?

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Average4.7

Average4.3

World 92% 99.6%US 96% 99.7%


Social Network Analysis:Second Example

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• Single day snapshot of a Snowball Sample of Political Blogs (N=1490)

• Manually assigned as Liberal or Conservative

• Focus on Blogrolls and front page citations

• Primary question: Cyber-balkanization?


Social Network Analysis:Balkanization (regular kind)

Process of fragmentation or division of a region or state into smaller regions or states that are often hostile or non-cooperative with each other.

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Social Network Analysis:Cyber-balkanization?

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Proliferation of specialized online news sources allows people with different political leanings to be exposed only to information in agreement with their previously held views.


Social Network Analysis:Cyber-balkanization?

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N=1490Edges = 16715

N=758Edges = 7301

N=732Edges = 7839

Liberals Conservatives


Social Network Analysis:Political Blogs – Cyberbalkanization?

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Social Networks:Political Blogs - Metrics

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Social Network Analysis:Statistical Network Models

A Statistical Network Model- Assumes that part of the structure

of an observed network is random- Mathematical description of a

collection of possible networks and a probability distribution on this set

- Informs us about which network characteristics to expect if lines assigned to pairs of vertices at random

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Social Network Analysis:Statistical Network Models

- Classic Bernouilli - Conditional Uniform- Small-World- Preferential Attachment

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Social Network Analysis:Political Blogs - Comparisons

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Social media mining hicss 46 part 2

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