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Lu Chen

Kno.e.sis CenterAmit Sheth

Wright State University

advisor of

has PhD student

is in

director of

Subjective Information Extraction, Lu Chen 2

Extracting What We Think and How We Feel from What

We Say in Social Media---- Subjective Information Extraction

Lu ChenKno.e.sis Center

Wright State University

http://cdryan.com/blog/think-feel/


Subjectivity refers to the subject and his or her perspective, feelings, beliefs, and desires. in philosophy, the term is usually contrasted with objectivity. [1]

[1] Block, Ned; Flanagan, Owen J.; & Gzeldere, Gven (Eds.) The Nature of Consciousness: Philosophical Debates. Cambridge, MA: MIT Press.

http://fineartamerica.com/featured/its-all-subjective-john-crowther.html

Extraction of subjective information:

• Extracting structured subjective information from unstructured content

• Allowing computation to be done on “what people think” and “how people feel”


Directions

• From coarse-grained to fine-grained– Document level -> sentence level -> expression level– General sentiment -> domain-dependent sentiment -> target-dependent sentiment– Sentiment Subjective information

• Sentiment (positive/negative/neutral) -> emotion (happy, sad, angry, surprise, etc.)• Other types of subjective information: Intent, suggestion/recommendation,

wish/expectation, outlook, viewpoint, etc.

• From static to dynamic– Our attitude can be changed during social communication.

• Modeling, detecting, and tracking the change of attitude• What leads to the change of attitude? E.g., persuasion campaign

static

dynamic

coarse-grainedfine-grained

subjective information


Jan, 2012Aug, 2011 May, 2012

Discovering Fine-grained Sentiment in

Suicide Notes

Extracting Sentiment Expressions from

Twitter

Electoral Prediction

Understanding and Modeling Emotions

with Tweets

Progress


Extracting a diverse and richer set of sentiment-bearing

expressions, including formal and slang words/phrases

Assessing thetarget-dependent polarity

of each sentiment expression

A novel formulation of assigning polarity to a sentiment expression

as a constrained optimization problem over the tweet corpus

Extracting Diverse Sentiment Expressions With Target-dependent Polarity from Twitter

Lu Chen, Wenbo Wang, Meenakshi Nagarajan, Shaojun Wang, and Amit P. Sheth


Challenges• Sentiment expressions in tweets can be very diverse.

Quantitative Study of 3000 Tweets: Distributions of N-grams and Part-of-speech of the Sentiment Expressions


Challenges• The polarity of a sentiment expression is sensitive to its target.

predictable

predictable movie

predictable stock

long

long river

long battery life

long time for downloading


Approach

Extracting Candidate Expressions

Identifying Inter-Expression Relations

Assessing Target-dependent Polarity


Extracting Candidate Expressions

• Root word: a word that is considered sentiment-bearing in general sense.

• Collecting root words from – General-purpose sentiment lexicons: MPQA, General Inquirer, and

SentiWordNet– Slang dictionary: Urban Dictionary

• For each tweet, selecting the “on-target” root words, and extracting all the n-grams that contain at least one selected root word as candidates


Identifying Inter-Expression Relations

• Connecting the candidate expressions via two types of inter-expression relations – consistency relation and inconsistency relation

• Basic ideas:– A sentiment expression is inconsistent with its negation; two sentiment

expressions linked by contrasting conjunctions are likely to be inconsistent.

– Two adjacent expressions are consistent if they do not overlap, and there is no extra negation applied to them or no contrasting conjunction connecting them.


An Example1. I saw The Avengers yesterday evening. It was long but it was very good!2. I do enjoy The Avengers, but it's both overrated and problematic.3. Saw the avengers last night. Mad overrated. Cheesy lines and horrible

writing. Very predictable.4. The avengers was good but the plot was just simple minded and predictable.5. The Avengers was good. I was not disappointed.


Assessing Target-dependent Polarity

• For each candidate expression , – P-Probability – the probability that indicates positive

sentiment– N-Probability – the probability that indicates negative

sentiment

• For each pair of candidate expressions and , – Consistency probability – the probability that and have the same

polarity:

– Inconsistency probability – the probability that and have different polarities:

ic)(Pr i

P c

)(Pr iN c

ic

ic

1)(Pr)(Pr iN

iP cc

ic jcic jc

)(Pr)(Pr)(Pr)(Pr),(Pr jN

iN

jP

iP

jicons cccccc

ic jc

)(Pr)(Pr)(Pr)(Pr),(Pr jP

iN

jN

iP

jiincons cccccc


An Optimization Model

• We want the consistency and inconsistency probabilities derived from the the P-Probabilities and N-Probabilities of the candidates will be closest to their expectations suggested by the relation networks.

• Objective Function:

1

1

22),(Pr1),(Pr1minimize

n

i

n

ijji

inconsinconsijji

consconsij ccwccw

where and are the weights of the edges (the frequency of the relations) between and in the consistency and inconsistency relation networks, and n is the total number of candidate expressions.

ic jcconsijw

inconsijw


The Example


Evaluation• Datasets:

– 168,005 tweets about movies– 258,655 tweets about persons

• Gold standard:– 1,500 tweets labeled with sentiment expressions and overall polarities for the

movie targets– 1,500 tweets labeled with sentiment expressions and overall polarities for the

person targets

• Baseline methods:– MPQA, GI, SWN: For each extracted root word regarding the target, simply

look up its polarity in MPQA, General Inquirer and SentiWordNet, respectively.– PROP: a propagation approach proposed by Qiu et al. (2009)– COM-const: Assign 0.5 to all the candidates as their initial P-Probabilities.– COM-gelex: Initialize the candidates’ polarities according to the root word set.Reference: Qiu, G.; Liu, B.; Bu, J.; and Chen, C. 2009. Expanding domain sentiment lexicon through double propagation. In Proc. of IJCAI.




Application


Relevance of User Groups Based on Demographics and Participation to Social Media Based Prediction

-- -- A Case Study of 2012 U.S. Republican Presidential PrimariesLu Chen, Wenbo Wang, and Amit P. Sheth

• Existing studies on predicting election result are under the assumption that all the users should be treated equally.

• How could different groups of users be different in predicting election results?

1. Providing a detailed analysis of the social media users on different dimensions

2. Estimating the “vote” of each user by analyzing his/her tweets, and predicted the results based on “vote-counting”

3. Examining the predictive power of different user groups in predicting the results of Super Tuesday races in 10 states


User Categorization

Engagement Degree

Tweet Mode

Content Type

Political Preference

Location


Electoral Prediction with Different User Groups

Revealing the challenge of identifying the vote intent of “silent majority”

Retweets may not necessarily reflect users' attitude.

Prediction of user’s vote based on more opinion tweets is not necessarily more accurate than the prediction using more information tweets

The right-leaning user group provides the most accurate prediction result. In the best case (56-day time window), it correctly predict the winners in 8 out of 10 states with an average prediction error of 0.1.

To some extent, it demonstrates the importance of identifying likely voters in electoral prediction.


Emotion• Discovering Fine-grained Sentiment in Suicide Notes: Classify each

sentence from suicide notes into 15 emotional categories, e.g., love, pride, guilt, blame, hopelessness, etc.

• Emotion Identification from Twitter Data: 7 emotion categories, including joy, sadness, anger, lover, fear, thankfulness, and surprise– Can we automatically create a large emotion dataset with high quality

labels from Twitter? How?– What features can effectively improve the performance of supervised

machine learning algorithms?– How much performance will be gained by increasing the size of the

training data?– Can the system developed on Twitter data be directly applied to identify

emotions from other datasets?


What’s next?

static

dynamic

coarse-grained fine-grained

subjective information

Detecting the change of

attitude during persuasive

communication

Discriminating other types of

subjective information from sentiment,

e.g., wish, intent


Thank you !

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