Midterm Review

POS

Tag	Part of Speech	Definition	Example
CC	Coordinating Conjunction	Connects words, phrases, or clauses of equal importance.	I like coffee and tea.
CD	Cardinal Number	Represents quantity.	She has three cats.
DT	Determiner	Introduces a noun, specifies quantity or definiteness.	The dog is barking.
EX	Existential "There"	Indicates existence.	There is a problem.
FW	Foreign Word	A word from another language.	He has a je ne sais quoi.
IN	Preposition or Subordinating Conjunction	Links nouns/pronouns or introduces dependent clauses.	The book is on the table.
JJ	Adjective	Describes a noun.	She wore a red dress.
JJR	Adjective, Comparative	Compares two things.	He is taller than me.
JJS	Adjective, Superlative	Shows the highest degree.	She is the smartest student.
LS	List Item Marker	Indicates list numbering.	1. Buy groceries.
MD	Modal Verb	Expresses necessity, possibility, or ability.	You should sleep early.
NN	Noun, Singular or Mass	A person, place, thing, or idea.	The car is fast.
NNS	Noun, Plural	More than one noun.	The dogs are barking.
NNP	Proper Noun, Singular	A specific name of a person, place, or organization.	John is my friend.
NNPS	Proper Noun, Plural	Plural proper noun.	We visited the Rocky Mountains.
PDT	Predeterminer	Appears before a determiner to specify quantity.	She spent all the money.
POS	Possessive Ending	Indicates possession.	That is John’s car.
PRP	Personal Pronoun	Replaces a noun.	She loves ice cream.
PRP$	Possessive Pronoun	Shows ownership.	This is my book.
RB	Adverb	Modifies a verb, adjective, or adverb.	She runs quickly.
RBR	Adverb, Comparative	Compares two actions.	He runs faster than me.
RBS	Adverb, Superlative	Shows the highest degree.	She arrived earliest.
RP	Particle	Forms part of a phrasal verb.	He gave up smoking.
SYM	Symbol	A special character or symbol.	Price: $100
TO	"to"	Used in infinitives or prepositions.	I like to read.
UH	Interjection	Expresses emotion.	Wow! That’s amazing!
VB	Verb, Base Form	Base form of a verb.	I want to run.
VBD	Verb, Past Tense	Action happened in the past.	She ran yesterday.
VBG	Verb, Gerund or Present Participle	"-ing" form of a verb.	He is running fast.
VBN	Verb, Past Participle	Used in perfect tenses.	He has eaten lunch.
VBP	Verb, Non-3rd Person Singular Present	Present tense (I/You/We/They).	They run every day.
VBZ	Verb, 3rd Person Singular Present	Present tense (He/She/It).	He runs fast.
WDT	Wh-Determiner	Introduces relative clauses.	This is the book that I lost.
WP	Wh-Pronoun	Used in questions.	Who is at the door?
WP$	Possessive Wh-Pronoun	Shows ownership in questions.	Whose bag is this?
WRB	Wh-Adverb	Used in questions for time, place, reason, etc.	Where is my phone?

Viterbi Algorithm

starting probabilities X emission probabilities X transition probabilities

TF-IDF

Term Frequency – number of times term t occurs in document

Inverse Document Frequency: Reciprocal of portion of large document set that contain term t, normalized with log function

IDF

Cosine Similarity

Precision, Recall, F-Measure