Sentiment Analysis and NLP Concepts
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Sentiment analysis, also known as ________, uses natural language processing to identify and classify emotions in text.

opinion mining

The three levels of sentiment analysis are ________, ________, and ________.

document level, sentence level, and entity and aspect level

Sentiment analysis aims to classify text into three categories: ________, ________, and ________.

positive, negative, neutral

The ________ level of sentiment analysis evaluates the overall sentiment of a document.

<p>document</p> Signup and view all the answers

One major challenge in sentiment analysis is understanding ________, such as 'not bad,' which can invert the sentiment.

<p>negation</p> Signup and view all the answers

The process of assigning a lexical class marker to each word in a corpus is called _______.

<p>Part-of-Speech Tagging</p> Signup and view all the answers

Words like 'in' and 'on' are part of the _______ class, which has a fixed membership.

<p>Closed</p> Signup and view all the answers

The _______ tagset consists of 45 tags and is widely used in NLP.

<p>Penn Treebank</p> Signup and view all the answers

Rule-based POS tagging relies on _______ crafted based on linguistic knowledge.

<p>Human</p> Signup and view all the answers

In probabilistic sequence models, _______ assumes the next state depends only on the current state.

<p>Hidden Markov Model (HMM)</p> Signup and view all the answers

Training data is typically split into _______ for model training and _______ for testing.

<p>90%, 10%</p> Signup and view all the answers

The metric that calculates the harmonic mean of precision and recall is called _______.

<p>F-measure</p> Signup and view all the answers

_______ is a problem where the contexts to be tagged do not appear in the training data.

<p>Out-of-Vocabulary (OOV)</p> Signup and view all the answers

A Markov Chain cannot represent _______ as it uniquely determines the path through states.

<p>Ambiguity</p> Signup and view all the answers

The extension of Markov Chains that includes hidden states is called _______.

<p>Hidden Markov Model (HMM)</p> Signup and view all the answers

In HMM, the probability of observing a specific output given a state is known as _______.

<p>Emission Probability</p> Signup and view all the answers

The _______ algorithm is used to compute the probability of an observation sequence.

<p>Forward</p> Signup and view all the answers

A left-to-right HMM commonly used in speech recognition is called a _______ HMM.

<p>Bakis</p> Signup and view all the answers

Probabilistic Context-Free Grammar (PCFG) is a CFG variant where each production rule has an associated _______.

<p>Probability</p> Signup and view all the answers

Treebanks are corpora annotated with _______ trees.

<p>Parse</p> Signup and view all the answers

The _______ pointers in the Viterbi algorithm trace the best path through the states.

<p>Backtracking</p> Signup and view all the answers

Statistical parsing uses a _______ model to assign probabilities to parse trees.

<p>probabilistic</p> Signup and view all the answers

A probabilistic version of CFG is called _______.

<p>Probabilistic Context-Free Grammar (PCFG)</p> Signup and view all the answers

The _______ grammar is a corpus annotated with parse trees, commonly used for supervised learning.

<p>treebank</p> Signup and view all the answers

In statistical parsing, the probability of a sentence is the _______ of the probabilities of all its derivations.

<p>sum</p> Signup and view all the answers

The _______ algorithm helps efficiently determine the most probable derivation for a sentence in PCFG.

<p>Viterbi</p> Signup and view all the answers

_______ parsing starts from the root of the parse tree and applies grammar rules to generate possible trees.

<p>Top-down</p> Signup and view all the answers

_______ parsing starts from terminal symbols and works backward to find the root.

<p>Bottom-up</p> Signup and view all the answers

The F1 score is the harmonic mean of _______ and _______.

<p>precision, recall</p> Signup and view all the answers

Sentiment analysis is often applied to sources like social media posts, ________, and ________.

<p>Product reviews, news articles</p> Signup and view all the answers

________ is an information-theoretic measure used to identify word associations or collocations in text.

<p>Pointwise Mutual Information (PMI)</p> Signup and view all the answers

________ is a Python library commonly used for implementing sentiment analysis using tools like classifiers and feature extraction.

<p>NLTK</p> Signup and view all the answers

Positive sentiment words include ________, ________, and ________.

<p>Love, amazing, helpful</p> Signup and view all the answers

Named Entity Recognition seeks to classify entities in text into predefined categories like ________, ________, and ________.

<p>Persons, locations, organizations</p> Signup and view all the answers

The ________ approach to NER uses predefined vocabulary lists to match entities in text.

<p>Dictionary-based</p> Signup and view all the answers

The spaCy command to extract named entities involves using the function ________.

<p>nlp()</p> Signup and view all the answers

________ is a Python library widely used for NER and natural language processing.

<p>spaCy</p> Signup and view all the answers

The interdisciplinary field combining Computer Science and Computational Linguistics is known as ______.

<p>Speech Recognition</p> Signup and view all the answers

Common audio formats used in speech recognition include WAV, MP3, and ______.

<p>M4A</p> Signup and view all the answers

One major challenge in speech recognition is the variability in ______.

<p>pronunciation</p> Signup and view all the answers

Python package used for offline recognition in speech processing is ______.

<p>Pocketsphinx</p> Signup and view all the answers

Voice Assistants are commonly found in phones, smart devices, and ______.

<p>cars</p> Signup and view all the answers

Speech is digitized using a microphone and an ______.

<p>analog-to-digital converter</p> Signup and view all the answers

One technique used in speech recognition involves ______ which helps in the analysis of speech signals.

<p>Neural Networks</p> Signup and view all the answers

Enhanced collaboration tools like Google ______ are a trend in the future of speech recognition.

<p>DuetAI</p> Signup and view all the answers

Study Notes

Speech Recognition

  • Interdisciplinary subfield combining computer science and computational linguistics
  • Converts human speech into text
  • Also known as automatic speech recognition (ASR) or speech-to-text
  • Replacing chat-based AI interfaces with voice input
  • Improved AI-powered voice assistants
  • Accessibility improvements (e.g., automatic captions)
  • Enhanced collaboration tools (e.g., Google DuetAI)

Speech Recognition Applications

  • Voice assistants (phones, smart devices, cars)
  • Speech-to-text tools (automated meeting transcription)
  • Accessibility tools for people with disabilities
  • Security (speaker recognition for authentication)

How Speech Recognition Works

  • Speech is digitized using a microphone and an analog-to-digital converter
  • Core techniques include neural networks, hidden Markov models (HMMs), and voice activity detectors (VADs)
  • Speech signals are analyzed at 10-millisecond intervals to generate cepstral coefficients (vectors representing signal features)

Challenges in Speech Recognition

  • Variations in pronunciation (dialects, accents)
  • Homophones ("bear" vs. "bare")
  • Impact of noise and emotion
  • Difficulty in identifying pauses or prosody

Speech Data and Formats

  • Common audio formats: WAV, MP3, M4A, WMA
  • Telephony systems use 8 kHz sampling rate
  • Human hearing range: 20 Hz–20,000 Hz

Speech Analysis Applications

  • Speaker diarization
  • Emotional classification
  • Text-to-speech (generating natural-sounding speech)

Python Packages for Speech Recognition

  • SpeechRecognition (Google Web Speech API wrapper)
  • Pocketsphinx (offline recognition)
  • Other APIs (Google Cloud Speech, IBM Speech to Text, Whisper (OpenAI))

Self-Exercise and Implementation

  • Record sentences as .wav files
  • Use Python libraries (e.g., SpeechRecognition) to recognize speech
  • Measure transcription accuracy

Statistical Parsing

  • Probabilistic Context-Free Grammar (PCFG)
  • Treebanks (corpora annotated with parse trees)
  • Treebanks for supervised learning of PCFGs
  • Parsing Techniques with PCFG (use of NLTK libraries such as InsideChartParser, ViterbiParser)
  • Probabilistic parsing: defines grammar, generates parse trees, calculates probabilities
  • Evaluation Metrics (recall, precision, F1-score in PARSEVAL)
  • Dependency Grammar (PSG): Represents syntactic structure through dependencies rather than phrases
  • Directed graphs between words, suitable for free word-order languages

Syntactic Parsing

  • Phrase Structure Grammar (PSG): Introduced by Noam Chomsky, using rewrite rules
  • Parsing as Search: Exploring all derivations for a given string
  • Top-Down Parsing: Starts with the root (start symbol)
  • Bottom-Up Parsing: Starts with terminal symbols, moving towards the root

Sentiment Analysis

  • Focuses on analyzing opinions, sentiments, and emotions in text
  • Uses NLP, statistics, and machine learning
  • Sentiment analysis known also as opinion mining
  • Key concepts include semantic orientation, polarity (e.g., positive, negative, or neutral)
  • Subjective impressions influenced by contextual polarity

Levels of Sentiment Analysis

  • Document level analyses overall sentiment
  • Sentence level identifies sentiment for each sentence
  • Entity/aspect level details sentiments concerning specific details (e.g., features of a product)

Challenges in Sentiment Analysis

  • Complexity of opinions in text
  • Issues like negation, sarcasm, and rhetorical devices

Steps in Sentiment Analysis using NLTK

  • Training classifier models on labeled data
  • Feature Extraction (e.g., Bag of Words model) to classify sentiments

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Description

This quiz tests your knowledge on sentiment analysis and related natural language processing (NLP) concepts. You will encounter questions about the levels of sentiment analysis, challenges faced, and various tagging techniques used in NLP. Enhance your understanding of how emotions are classified in text.

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