By Adam Anderson
What is it?
• A crowd sourced knowledgebase of common sense
Common Sense
• We have it and rely on it a lot
• Computers do not
• How am I feeling:
• I had an awful day.
• I got fired today.
• What else can be inferred by the sentences?
Common Sense Challenge
Marvin Minsky made an estimation:
‘…commonsense is knowing maybe 30 or 60
million things about the world and having them
represented so that when something happens, you
can make analogies with others’
WordNet and Cyc
• Two semantic knowledge basis that inspired ConceptNet
• Comparable in size and effort
WordNet
• Began in 1985 at Princeton University
• Words organized into discrete ‘senses’
• Words are linked by semantic relationships
• Synonym
• Is-a
• Part-of
• Great for lexical categorization and word-similarity
determination
ConceptNet vs WordNet
• ConceptNet focuses on semantic relationships between
compound concepts
• Drive car
• 20+ semantic relationships
• Contains knowledge that is defeasible
Cyc
• Started in 1984 by Doug Lenat
• A formalization of a commonsense knowledgebase into a
logical framework
• Uses its own unambiguous logical formulation language
called CycL
• All assertions and facts are entered in by knowledge
engineers of Cycorp
ConceptNet vs Cyc
• ConceptNet doesn’t use a formalized logical framework
• ConceptNet is openly available to the public
• The largest difference is how ConceptNet gets its data
• It uses crowdsourcing to retrieve data from the general public, and
not just knowledge engineers.
Open Mind Common Sense
(OMCS)
• Developed at MIT in 1999
• Inspired by the success of other collaborative projects on
the Web
• A website containing 30 activities
• Each giving a simple commonsense assertion
• Quickly gathered over 700,000 sentences from over
14,000 contributors
CRIS
• Commonsense Robust Inference System
• Earliest precursor to ConceptNet
• Tried to extract taxonomic, spatial, functional, causal, and
emotional knowledge from OMCS to populate a semantic
network
• Idea of letting users provide information in semi-structured
natural language instead of directly engineered structures
Cyc used
OMCSNet
• A semantic network built on top of CRIS
• Had a small three function API
• Used in many MIT Media Lab projects
ConceptNet
• ConceptNet was the next interation
• Added system for weighing knowledge
• How many times in OMCS corpus
• How well can it be inferred indirectly from other facts
• Multiple assertions inferred from single OMCS sentence
• Addition of NL tools like MontyLingua
ConceptNet 5
• A lot has changed since 2004
• Many structural changes have occurred in each version.
• We will discuss the current structure in a bit
• Many new data sources
• Development is currently being led by Rob Speer and
Catherine Havasi
Current Sources
• Still uses OMCS
• WordNet
• English Wikipedia
• DBPedia
• ReVerb (Removed in v5.2)
• Even games
• GWAP project’s game
Verbosity
• Japanese game
nadya.jp
• English Wiktionary
• Synonyms
• Antonyms
• Translations
• Labeled word senses
Assertions
Two concepts connected by a relation
and justified by sources
Types of Relations
• IsA
• Desires
• UsedFor
• MadeOf
• RelatedTo
• CapableOf
• AtLocation
• TranslationOf
• HasA
• InheritsFrom
• DefinedAs
• LocatedNear
• CreatedBy
• Synonym
• HasProperty
• Antonym
• DerivedFrom
• ConceptuallyRelatedTo
• MotivationOf
• EffectOf
Structure
• ConceptNet is represented as a hypergraph
• Edges in a hypergraph (hyperedges) are sets of nodes
that contain an arbitrary number of nodes
• Concept of k-uniform
Structure: Concepts & Predicates
Concepts
• Words and phrases
• Represented as nodes
Predicates
• Set of relations such as IsA or HasA
• Also represented as nodes
Structure: Assertions
• Represented by edges in the graph that connect multiple
nodes in the graph (concepts and relations)
• Justified by other assertions, knowledge sources, and
processes
• An edge is an instance of an assertion. Multiple edges
can represent the same assertion. An assertion is a
bundle of edges
• Think of each edge has being a way that assertion was learned
Structure: Sources
• Sources justify each assertion
• Each edge contains a conjunction of sources that justify
that edge
• 𝑆1 ∧ 𝑆2 ∧ 𝑆3
• The sources that justify an assertion are represented by a
disjunction of conjuctions
• 𝑆1 ∧ 𝑆2 ∧ 𝑆3 ∨ 𝑆4 ∧ 𝑆5 ∨ (𝑆6 ∧ 𝑆7)
Structure: Source Score
• Each conjunction has a score
• More positive gives more confidence that the assertion is true
• More negative gives more confidence that the assertion is false
• Negative scoring doesn’t mean that the negation of the assertion is true
• Consider “Pigs cannot fly”
• Should be represented using negated relations like NotCapableOf
• Needed to assign credit in the multi-part process to create
the assertion
Web Frontend
• http://conceptnet5.media.mit.edu/
Using ConceptNet
• JSON REST API
• Running it locally
• Can choose which data to use and add more data
• All the data is available for convenience
• Flat JSON file
• Solr JSON file
• CSV
REST
• Representational State Transfer
• Is defined by 6 constraints
• Client-server
• Stateless
• Cacheable
• Layered System
• Code on demand
• Uniform interface
REST Web API
• Has a base url: http://mysite.com/api/
• Uses an internet media type such as JSON, XML, or
YAML
• Supported by HTTP methods (GET, PUT, POST, and
DELETE)
• Hypertext Driven
REST Web API
ConceptNet only allows GET API use
JSON
• Javascript Object Notation
• Text-based open standard designed for human-readable
data interchange
JSON Edge Data
• id: the unique ID for this edge, which contains a SHA-1 hash of
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the information that makes it unique.
uri: the URI of the assertion being expressed. The uri is not
necessarily unique, because many edges can bundle together
to express the same assertion.
rel: the URI of the predicate (relation) of this assertion.
start: the URI of the first argument of the assertion.
end: the URI of the second argument of the assertion.
weight: the strength with which this edge expresses this
assertion. A typical weight is 1, but weights can be higher,
lower, or even negative.
sources: the sources that, when combined, say that this
assertion should be true (or not true, if the weight is negative).
JSON Edge Data
• license: a URI representing the Creative Commons license
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that governs this data. See Copying and sharing ConceptNet.
dataset: a URI representing the dataset, or the batch of data
from a particular source that created this edge.
context: the URI of the context in which this statement is said
to be true.
features: a list of three identifiers for features, which are
essentially assertions with one of their three components
missing. These can be useful in machine learning for inferring
missing data.
surfaceText: the original natural language text that expressed
this statement. May be null, because not every statement was
derived from natural language input. The locations of
the start and end concepts will be marked by surrounding them
with double brackets. An example of a surfaceText is "[[a cat]]
is [[an animal]]".
JSON Edge Data Example
ConceptNet Web API
• Lookups
• http://conceptnet5.media.mit.edu/data/5.1
• Search
• http://conceptnet5.media.mit.edu/data/5.1/search
• Association
• http://conceptnet5.media.mit.edu/data/5.1/assoc
Lookup Base URIs
• /a/: assertions
• /c/: concepts (words, disambiguated words, and phrases, in a
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particular language)
/ctx/: contexts in which assertions can be true, if they're
language independent.
/d/: datasets
/e/: unique, arbitrary IDs for edges. Edges that assert the same
thing combine to form assertions.
/l/: license terms for redistributing the information in an edge.
/r/: language-independent relations, such as /r/IsA
/s/: knowledge sources, which can be human contributors, Web
sites, or automated processes
Let’s Try Some Lookups
• http://conceptnet5.media.mit.edu/data/5.1/c/en/dragon
Example Search
• Searching for 10 things that are part of a car
• http://conceptnet5.media.mit.edu/data/5.1/search?rel=/r/PartOf&en
d=/c/en/car&limit=10
Association
• Finds concepts that are similar concept or term list
• Can specify the GET parameter filter to only return results
that start with the given URI
Examples
• Measure how similar dogs and cats are
• http://conceptnet5.media.mit.edu/data/5.1/assoc/c/en/cat?filter=/c/e
n/dog&limit=1
• Find terms associated with these breakfast foods
• http://conceptnet5.media.mit.edu/data/5.1/assoc/list/en/toast,cereal,
juice@0.5,egg
Conclusion
• It is just common sense
• Easy, right?
Questions?
Sources
• http://csc.media.mit.edu/conceptnet
• http://conceptnet5.media.mit.edu/
• http://en.wikipedia.org/wiki/Open_Mind_Common_Sense
• http://web.media.mit.edu/~hugo/publications/papers/BTTJ
-ConceptNet.pdf
• http://en.wikipedia.org/wiki/Representational_state_transf
er
• http://en.wikipedia.org/wiki/Hypergraph