A Semantic Frame Graph for Information Extraction
Michał Gałusza
Faculty of Cybernetics, Military University of Technology, Warsaw, Poland
Keywords:
Information Extraction, Relationship Detection, Natural Language Processing, Graphical Representation of
Text.
Abstract:
The following paper describes a graphical representation of a short text based on the semantic frames (the
Semantic Frame Graph) using Semantic Role Labeling (SRL). It can be a foundation of alternative approach
for open information extraction (OIE). The approach postprocesses the output of pretrained SRL classifier
and it does not use complex rules, training sets nor significant corpus to decompose sentences. Proposed de-
composition and representation reduces number of paths between entities dropping ones that are linguistically
unmotivated, generates sequences of frames as paths which can be controlled using dialog coherence approach
which further increases plausibility of semantic relationship between entities.
1 INTRODUCTION
Information Extraction (IE) is a process of converting
unstructured information held in text into a structured,
for example, graphical representation as in knowledge
graphs (KG). The KGs represent information as typed
relations between entities, which are fundamental for
developing methods that have the potential for sophis-
ticated reasoning (Ji, 2021).
Open Information Extraction (OIE) paradigm
aims to extract all possible semantic relationships be-
tween entities available regardless of the genre of text
(financial, medical or technical). This is achieved
without dedicated, supervised training of anticipated
relationships. OIE systems, however, are not fully
unsupervised. They use a collection of patterns,
seeding samples, predefined heuristics, scoring func-
tions and distant supervision (Fader, 2011),(Banko,
2007),(M. Schmitz, 2012) to search for relationships.
Patterns and heuristics need to be calibrated there-
fore large corpus and significant seed samples are re-
quired. However, OIE systems (Fader, 2011),(Banko,
2007),(M. Schmitz, 2012) were created to efficiently
parse large web resources and automatically detect
all existing semantic relations. Efficient OIE system
must possess following features (Niklaus, 2018):
automation: relationships must be extracted with-
out any prior training of them in unsupervised
manner;
corpus heterogeneity: relationships must be ex-
tracted in various genres of text;
efficiency: extraction shall be possible in large
web corpus.
Despite their success, current OIE systems are still
faced with ve main challenges pertaining to relation-
ship extractions (Niklaus, 2018):
overlaps: where same sentence fragment may
generate multiple triples (subject, relation, ob-
ject), for example, because of shared subject;
discontinuation: where a text spans supporting the
triples are is separated by an interval i.e. distant
direct object;
nesting: where one relation contains other relation
as in complex sentences;
distribution: where subject, relation and direct ob-
ject mentions break a sentence and they are in dif-
ferent contexts. It is natural for a human to iden-
tify such cases, however, this still posses a chal-
lenge for current extraction and classification so-
lutions;
reliability: in general they do not return meaning-
ful results on too small corpus
This paper describes a method to represent a short
texts as a Semantic Frame Graph, which will:
provide a method to limit negative impact of over-
laps, discontinuation, nesting and especially dis-
tribution in relationship extraction;
allow identifying relationships in short texts;
fulfill automation and corpus heterogeneity re-
quirement;
Gałusza, M.
A Semantic Frame Graph for Information Extraction.
DOI: 10.5220/0011729300003411
In Proceedings of the 12th International Conference on Pattern Recognition Applications and Methods (ICPRAM 2023), pages 435-442
ISBN: 978-989-758-626-2; ISSN: 2184-4313
Copyright
c
2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)
435
use Semantic Role Labeling to pre-process a text
instead of complex dependency parsing;
compare relation extraction efficiency using dia-
log coherency approach.
2 RELATED WORK
2.1 Open Information Extraction
The first solution formally introducing OIE was Tex-
tRunner (Banko, 2007). Its primary goal was to obvi-
ate manual adjustment of the extraction rules in case
of corpora or a target relation shift. TextRunner was
making a single pass over the corpus heuristically ex-
tracting relations triple centered around a verb phrase
(VP) with a specific subject and direct object. It at-
tempted to find the best arguments for that relation
applying additional heuristics e.g. neither head nor
target consist solely of a pronoun. A Naive Bayes
was used as an estimator of a confidence function that
was then trained over a set of features on the extrac-
tions so that the system could provide calibrated con-
fidence values. Comparing to the last pre OIE solu-
tion, KnowitAll, quality of extraction and its perfor-
mance significantly improved. Apart from that in Kn-
woItAll relations had to be specified upfront (Oren Et-
zioni, 2005). ReVerb (Fader, 2011) introduced addi-
tional syntactic and lexical constraints to limit inco-
herent and uninformative extractions of TextRunner
in detecting distant relationships. For example: ”The
Obama administration is offering only modest green-
house gas reduction targets at the conference.would
yield a relation ”is offering only modest greenhouse
gas reduction targets at” between ”The Obama ad-
ministration” and ”the conference”.
Fast dependency parsers and their ability to cre-
ate a sentence Dependency Tree (DT) allowed con-
struction of more sophisticated templates that further
increased precision and recall of extraction. OLLIE
(M. Schmitz, 2012) defined ”Open Relation Patterns”,
which, using a dependency tree, were mediated by
nouns and adjectives, not just verbs. OLLIE’s pro-
cessing began with seed tuples from REVERB and
used them to build a bootstrap training set. It learned
open pattern templates applied to individual sentences
at extraction time.
The latest advancement in OIE is related to the lat-
est progress in language modeling. The Transformer
architecture leads to a novel paradigm of Neural Open
Information Extraction (NOIE), (Zhou, 2022). NOIE
approaches extractions from two major directions:
Tagging and Generation.
Tagging-based solutions use annotation of tags’
sequence corresponding to facts in the input sentence.
The Generation-based ones directly decode relations
relying on Sequence2Sequence architecture. Both
tagging and generation paradigms predicts relation-
ships auto-repressively, which means the current pre-
diction relies on the previous output (Zhou, 2022). A
skewed prediction will be inherited and magnified in
the later steps. As the number of steps grows, errors
accumulate and may decrease the performance.
An exemplary graph-based approach (Yu, 2021)
breaks the auto-regressive factorization by construct-
ing a graph where nodes are text spans and edges con-
necting them indicate that they belong to the same
fact. Relationship discovery task is cast as maximal
clique detection.
2.2 Semantic Role Labeling
Frame Semantics was originally introduced by
Charles J. Fillmore (Charles, 1977) with the basic
idea that one cannot understand the meaning of a sin-
gle word without access to all the essential knowledge
related to that word, namely, its semantic frame. The
semantic frame is strictly associated with the word’s
meaning expressed in the sentence. Semantic Role
Labelling (SRL) (D.Gildea, 2000) (D.Jurafsky, 2022)
identifies and models frame’s structure. SRL takes
a sentence and identifies verbs and their arguments.
Then, it classifies the arguments by mapping them to
roles relevant to the verb in that frame, such as agent,
patient, instrument, or benefactor. In other words,
SRL tries to identify ”Who, What, Where, When,
With What, Why, How” for each frame. A state-of-
the-art deep pre-trained SRL model (Peng Shi, 2019)
detects the simplified structure of a frame where in-
stead of an agent, a patient, an instrument it detects
generic simplified arguments of a verb: ARG0, ARG1
and others. The structure of the frame highly corre-
lates with the dependency tree (DT) of the sentence
(T.Shi and O.Irsoy, 2020), where the verb and verb’s
arguments create constituencies (noun phrases NPs
and verb phrases VPs). Moreover, it is possible to
reduce the SRL task to a Dependency Parsing task
(T.Shi and O.Irsoy, 2020) . In addition, SRL offers an
efficient approach to the problem of the decomposi-
tion of complex sentences which was initially solved
by a trained, dedicated, classifier splitting a sentence
into shorter utterances (Angeli, 2019).
2.3 Knowledge Graphs
Constructing an ontology from text is challenging
due complexity of human language. Initial approach
ICPRAM 2023 - 12th International Conference on Pattern Recognition Applications and Methods
436
to construct a knowledge graph relied on syntactical
parsing for terms, synonyms, concepts, relationships
between them, their hierarchies. On top of them a set
of axioms were created (or inferred from text) to be
a set of logical implications constraining the interpre-
tation of concepts and relations therefore governing
inference (D. Maynard, 2017), (Cimiano, 2006).
A semantic frame serves two purposes: it is a
means to abstract a cognitive schemata and it is this
schemata computational counterpart (A. Gangemi,
2010). Structure of semantic frame naturally identi-
fies objects in the sentence (as they are frame’s ar-
guments) and relationship between them (as it is a
verb) (M. Alam, 2021). There are two limitations to
that approach. First, neither concepts nor their hier-
archies can be automatically detected. Second, con-
necting frames needs to be contextualized and sup-
ported by the text, meaning that connections mediated
by co-occuring terms often require additional valida-
tion to make sure they form a logical flow. For exam-
ple sentences: ”Astra Zeneca was first to develop a
Covid19 vaccine. Covid19 was a serious threat to a
global health in 2020 and 2021” may generate a rela-
tionship between Astra Zeneca and threat to a global
health through Covid19. Therefore a situation needs
to be reconstructured from original text in order to
validate the relationship (M. Alam, 2021). This pa-
per addressed this problem specifically using dialog
coherence approach to measure quality of connection
between frames.
3 SEMANTIC FRAME GRAPH
Formally, a Semantic Frame Graph is an undirected,
attributed, heterogeneous graph
G = (V, E)
where:
V is a set of nodes of following types:
Noun : nouns detected in a frame.
Argument : a span of text describing semantic
role of a frame
Frame : verb identifying a frame.
E is a set of edges that represents a specific seman-
tic role type: ARG0, ARG1, ...,. An edge ’VERB’
is used if argument is further split into a frame; an
’NOUN’ edge links nouns in the argument in case
there is no more frames.
The graph is constructed by applying SRL identifica-
tion (Peng Shi, 2019) on every sentence in the corpus.
A general structure of the graph is depicted in Figure
1.
Figure 1: Semantic Frame Graph Structure.
A Semantic Frame Graph decomposes a sentence
into a hierarchical structure of its frames.
SRL groups words per detected structure of the
frame and yields a structure that correctly segments a
sentence, solving, for example, the TextRunner’s dis-
tant relationship issue (Figure 2). It does it without
implementing any additional constraints and correctly
detects that ”conference” is a location, not a direct
object of the verb: ”offer” as in exemplary sentence:
”The Obama administration is offering only modest
greenhouse gas reduction targets at the conference.
A corresponding SFG captures the structure detected
by SRL (Figure 3).
Figure 2: Example Semantic Decomposition.
Figure 3: SFG Capturing Semantic Decomposition.
SFG decomposes complex sentences and in case
of overlaps and discontinuations properly linking re-
mote subjects and objects. Frames are always fully
defined in its direct neighborhood which means that
verbs without arguments are dropped. Comparing to
the initial attempt (Angeli, 2019), where this task was
cast as a linguistically driven search problem over a
sentence DT, SFG relies in the SRL decomposition.
For example, a sentence (Angeli, 2019): ”Born in a
small town, she took the midnight train going any-
where” is parsed to SFG (figure 4):
A Semantic Frame Graph for Information Extraction
437
Figure 4: SFG Complex Sentence Decomposition.
The direct neighborhood of verbs creates com-
plete frames, which are similar to a target shorter
utterances (Angeli, 2019). It captures directly ex-
pressed relationships as: ”she born in a small town”,
”she took the midnight train going anywhere”, ”she
going anywhere”. Although the third utterance does
make sense, it is incorrect from DT parsing perspec-
tive, I will discuss it in summary. Sentence decompo-
sition correctly identifies ”she” as a shared subject for
the first and the second utterances and skipping ”took
the midnight train” completely for the third utterance
which separates subject with the verb.
The SFG captures a hierarchy of frames as in a
sentence ”A water landing of a jetliner that lost both
engines due to hitting birds became known as the Mir-
acle on the Hudson River” (Figure 5)
Figure 5: SFG Hierarchy of Frames.
SFG allows modeling distant relationships in the
text that beyond single sentence. It allows linking
mentions in the text that are outside of defined con-
text window. The following example takes sentences
describing a specific type of jet fuel. ”An airplane
uses engines for flying. ATF is a type of aviation fuel
designed for use in aircraft powered gas-turbine en-
gines. (...) If these supercooled droplets collide with a
surface they can freeze and may result in blocked fuel
inlet pipes.
The relationship between entities (nouns) exists if
there is a path in SFG joining them. A path of seman-
tic frames joining them will create a passage that will
define a relationship that can be classified.
For example a path between water and an engine:
”water” ”supercooled water droplets collide with
a surface” ”if supercooled water droplets collide
with a surface they may result in blocked fuel inlet
pipes” ”blocked fuel inlet pipes” ”aviation fuel
designed for use in aircraft powered by gas turbine
engines” ”an airplane uses engines for flying”
”engine”
The generated path may indicate that ”water” im-
pacts ”engine” that may also impact the safety of
”flight”
4 SHORT TEXT
REPRESENTATION
In this section will compare an SFG graph with a Sen-
tence Graph (SG) which does not perform decom-
position. I will use a short text (12 sentences) de-
scribing news excerpt on Iraq War as in (D.Radev,
2004). The SG approach (D.Radev, 2004) constructs
a weighted graph of sentences where connections are
defined by co-occurring nouns and connection weight
equals the similarity between two sentences defined
by idf-modified-cosine. The threshold on the simi-
larity manages connectivity of the graphs and hence
quality of the paths.
A Table (1) summarizes structure. A sample con-
text, around noun ”Baghdad” is provided in Figures
(7) and (8). An SFG represents semantics of the text
in more compact manner and even without any thresh-
olds it can reduce number of paths almost 76 times.
In general, the problem of detecting a relationship be-
tween entities can be cast as finding a path between
them. Structure of the graph impacts the performance
of relationship extraction.
Table 1: Graphs’ structure comparison.
metric SG SFG
number of nodes 144 194
number of edges 193 219
number of noun nodes 76 76
number of verb nodes 57 60
number of paths 3901764 51040
A centrality (PageRank) of words (Table 2) shows
that 8 out of 10 top words are preserved in an SFG
representation so there is insignificant semantic drift
between both representations.
ICPRAM 2023 - 12th International Conference on Pattern Recognition Applications and Methods
438
Figure 6: SFG Distant Relationships.
4.1 Coherence of Paths and
Relationship Extraction
SFG represents frames which are singular sentences.
Therefore a path between any entities is a sequence of
generated singular sentences. Such a sequence can be
measured for its coherence.
The SFG represents a set of N frames
F : { f
1
, f
2
, ..., f
N
}
if the similarity of frames has the property that
s : f
i
, f
j
F, 0 s( f
i
, f
j
) 1 (1)
then the coherence c of a path p containing K frames
I define as the minimum similarity of the neighboring
frames in the path:
c
p
: min
0 j<K
s( f
j
, f
j+1
) (2)
There are various realizations of function (1)
available: sentence similarity (N. Reimers, 2019),
textual entailment (Poliak, 2020).
I update (B. Grosz, 1995) approach to meet re-
quirements of function (1) and I replace a direct
noun expressions to evaluate continuation retaining
and shifting with a semantic approach.
I use the fact that frame’s subject and object (cen-
ters) are decomposed into ARG0 and ARG1 roles
A Semantic Frame Graph for Information Extraction
439
Figure 7: A ”Baghdad” SG Context.
Table 2: Top 10 key words comparison.
pageranked position sentence frame
1 Iraq Iraq
2 United United
3 Nations today
4 today Baghdad
5 Prime Prime
6 Baghdad inspector
7 Minister Minister
8 inspector Nations
9 Blair year
10 Ivanov work
and I update the original centering approach using
zero-shot label classification. Instead of continua-
tion/retention/shift signals I evaluate cosine distance
between classification of backward centers of current
frame vs. previous.
The Wikipedia’s page for Teton Dam http://en.
wikipedia.org/wiki/Teton Dam is used as an example
to identity if selected object (a storage tank) posed a
risk and what kind of risk to another object (a city) in
the event of Teton Dam collapse.
Percentage of coherent path give minimal thresh-
old (Figure 9) shows that RTE immediate drop in-
dicating that frames are rather not each other entail-
ments and coherent passage will have low coherence
score making it difficult to find.
Best paths with best coherence score for each eval-
uation method (tab. 3) show that modified centering
approach on the SFG linked all related sentences from
original text to form a passage confirming that there
is a semantic relationship between a storage tank and
a city.
Table 3: Best paths for coherence types.
path c p type
Dozens of logs hit a bulk
gasoline storage tank a few
hundred yards away
When the flood waters hit
thousands of logs washed into
town
When the flood waters hit
The city of Idaho Falls even
further down on the flood
plain had time to prepare
0.52
semantic
similarity
Dozens of logs hit a bulk
gasoline storage tank a few
hundred yards away
The gasoline sent flaming
slicks adrift on the racing wa-
ter
When the flood waters hit
The city of Idaho Falls even
further down on the flood
plain had time to prepare
0.21 RTE
Dozens of logs hit a bulk
gasoline storage tank a few
hundred yards away
The gasoline sent flaming
slicks adrift on the racing wa-
ter
When the flood waters hit
thousands of logs washed into
town
The force of the logs and
cut lumber and the subsequent
fires practically destroyed the
city
0.85 centering
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Figure 8: A ”Baghdad” SFG Context.
Figure 9: Fraction of coherent paths given threshold.
5 CONCLUSION
A Semantic Frame Graph is an alternative represen-
tation of text. It uses SRL as pre-processing step
to identify the structure of frames. A whole set of
frames is loaded into a graph that is used as a foun-
dation for identifying relationships between selected
words. It links mentions distant in text, even across
sentences. It does not use a complex rule-based ap-
proach that requires bootstrapping nor significant cor-
pus to validate them as in early OIE solutions. Even
without any additional edges’ weighting and thresh-
olds on them, it shows significant reduction in number
of paths between entities so further classification of
them to proper relationships will require less compu-
tation. Modified centering approach measures over-
all coherence of paths between entities and thresholds
enables control of the quality of the connection that
can be classified for its type afterwards.
A few issues can be solved to increase text rep-
resentation quality further. Current state-of-the-art
SRL parser (Peng Shi, 2019) can be augmented with
additional post-processing steps to correct the align-
ment of SRL tags with a sentence’s dependency tree.
In exemplary sentence (Figure 5), for detected frame
”she going nowhere” a subject is ”train” which is
visible in its dependency tree. A progress in a co-
reference resolution will further increase the quality
of the graph not only because pronouns will be prop-
erly replaced by nouns they refer to, but also descrip-
tive expressions like ”this event”, ”in this case” will
properly link the frame with a noun or noun phrase
mention in the text.
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