=Paper= {{Paper |id=Vol-2673/paperDC2 |storemode=property |title=Process Extraction from Natural Language Text |pdfUrl=https://ceur-ws.org/Vol-2673/paperDC2.pdf |volume=Vol-2673 |authors=Patrizio Bellan |dblpUrl=https://dblp.org/rec/conf/bpm/Bellan20 }} ==Process Extraction from Natural Language Text== https://ceur-ws.org/Vol-2673/paperDC2.pdf
       Process Extraction from Natural Language Text

                         Patrizio Bellan 1,2 [0000-0002-2971-1872]
       1
           Process and Data Intelligence group, Fondazione Bruno Kessler, Povo (Tn), Italy
                     2
                       Free University of Bozen-Bolzano, Bolzano (Bz), Italy
                                         pbellan@fbk.eu



 1   Introduction and Problem Definition
 Public and private organizations always seek to achieve high standardization and improve
 performance of their business processes. Having control over business times, costs,
 errors and redundancy is vital to survive from continuous business revolutions [18, 31].
 Business Process Management is a discipline that aims to discover, analyze, and optimize
 business processes, typically represented in model diagrams. Unfortunately, the initial
 elicitation of a process model from documents is a time consuming and cost intensive
 operation, as argued in [15, 21]. Therefore, companies and the scientific community are
 interested in discovering novel algorithmic procedures to alleviate the initial creation of
 process models from documents.
      The extraction of a process model from documents is a complex task since the analy-
 sis of the natural language description of a process may produce multiple interpretation.
 This task is made up of three main activities. Filtering uninformative sentences of the
 process description out, because not all the sentences represent a process element. Then,
 the extraction of the process elements described in the text takes place. Finally, process
 elements discovered have to be logically organized following the semantic conveyed in
 the process description. So, defining the logical succession of process model elements
 is the last challenge to tackle. However, not only each sentence can describe multiple
 process elements, but also each word can have multiple meanings. To determine the
 correct intended meaning and to map it into the corresponding process element implies
 considering these two aspect at once. Also, there is the need to take care simultane-
 ously of the multiple linguistics levels (syntactical, semantics and pragmatics) as well
 as ambiguities due to natural language.
      The common solution found in the literature to solve the problem of process ex-
 traction from natural language text relies on a two-steps transformation approach with
 intermediate representation. Here, the model is considered as a compound function
 in which the first function fa extracts process elements from a text and populates the
 structured intermediate representation, while the second function fb builds the process
 model from the intermediate representation. However, most contributions proposed in
 this area date back to several years ago and, hypothetically, they may be considered
 outdated, given the advances of Natural Language Processing (NLP) techniques in the
 last few years [22]. Maqbool et al. argue in [21] that current approaches may be not able
 to scale up to real world scenarios, highlighting the need of research in this direction.
 The limited data publicly available and the heterogeneous approaches proposed in the
 literature highlighted a lack of a fair comparative analysis among them by making hard




Copyright © 2020 for this paper by its authors. Use permitted under Creative Commons
License Attribution 4.0 International (CC BY 4.0).
2        P. Bellan

the evaluation of their strengths and weaknesses [22]. While the maturity of Event-log
Process Mining is well established in literature [9], this research direction is still in an
early stage of development [4, 21].
    Among all the contributions, the work of Friedrich et al. [13] is still the state-of-
the-art, as emphasized in recent surveys and overviews on this topic such as the ones
presented in [4, 21]. These two papers also highlight that after almost ten years of
research, process extraction from natural language text is a task far from being resolved.
Therefore further research in this direction is needed with the purpose of improving the
quality of the process model generation.


2    Literature Analysis

Since the beginning of this line of research, the most common approach to mine processes
from documents rely on the use of lists of signal words (also called trigger words)
together with rules in the form of either patterns or templates. Important works ,selected
on the basis of their impact in terms of citations, that follow this approach are the ones
in [1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 19, 20, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33].
     There are three different approaches adopted in the literature. The one proposed by
Han et al. in [14] that aims to build a direct mapping between a process description and
its corresponding formal representation via neural transformation. A second solution,
proposed in [10], is grounded on the philosophy of learning by doing, that is, learning
a mapping of process model elements from a textual process description through user’s
feed-backs, incrementally. The third solutions, adopted in [3, 5, 8, 11, 12, 13, 16, 19],
uses a two-steps transformation with intermediate representation approach in which in
the first step, the process elements are identified in the text and memorized in a structured
representation, then in the second step the corresponding process model is generated
from the structured representation .
     Regarding the type of process model generated, these contributions can be divided
in two groups. The first group includes the solutions that generate an imperative pro-
cess model, in which each process element has a fixed relation with the other process
elements [6, 7, 8, 10, 11, 12, 13, 14, 16, 19, 24, 27]. The second group includes the
only two contributions found in the literature that aim to generate a declarative process
model in which the behavior of a process is expressed with constraints on the relation
between its process elements [5, 20].
     The comparison of all these cited contributions on the experimental evaluation level
reveals that the proposed solutions were tested on different aspects of the discovery task,
using different data sets and evaluated according to different metrics. This highlights
a lack of uniformity in the evaluation step that makes a comparison of the proposed
contributions rather difficult. An important cause of this can be found in the absence of
a common benchmark for the evaluation and in the absence of a common testing data set
to compare the works. If we focus on the metrics we can notice that the works analyzed
exploit different measures. The works proposed in [3, 5, 7, 10, 11, 12, 19, 24] adopt
information retrieval metrics to quantitatively evaluate the performance of the proposed
systems on the quality of the elements extracted from the process textual description.
                                     Process Extraction from Natural Language Text        3

In [13, 14] a graph-based measure quantitatively evaluate the quality of the process
model created by the proposed systems from the textual description of a process.


3   Limitations
The analysis of the literature reveals that this area of research is still in an early stage
of development, with many challenges still unanswered. Focusing on the research gaps
found the analysis of these contributions reveals that they present three main limitations.
L1 Limitations with the techniques adopted, because current contributions are highly
tailored to data input considered. In fact, when the state-of-the-arts (imperative and
declarative) where tested on a private data set of standard operative procedures (SOP)
they were not able to produce any diagrams.
L2 Limitations with the data. The works presented in [5, 6, 7, 8, 10, 12, 13, 19, 27]
all adopt the data set (or a subset of it) proposed by [13]. The problem with this data
set was not validated and thus it is not a representative sample of the variety of real
scenarios. A comparison of it with some SOP documents adopted in a factory revealed
that they differ greatly in: (i) the number of uninformative sentences/relative clauses,
(ii) an extensive use of abbreviations, (iii) technical words, (iv) rare words; (v) writing
styles, and (vi) formatting style.
L3 Limitations with the metrics adopted to judge the quality of the proposed systems,
because there is a lack of metrics that consider a wide range of possible errors, assigning
different weight for each type of errors, at once.


4   Research Questions
Starting from these limitations I formulate the following research questions.
RQ1 How far can the adoption of a statistical machine learning approach be superior
(in terms of error reduction) to the rule-based solutions?
In particular, RQ1.1 Can the adoption of statistical machine learning classifiers enhance
the performance in discriminating process elements described in a text?
RQ1.2 Which are the most predictive linguistics features to extract from a text that
allow to enhance the detection of process elements?
RQ2 Is it possible to use NLP models trained in other domains into this context without
re-training these models on process descriptions?
RQ3 Can I propose new bench-marking procedures with new data and new metrics
(that consider a wide range of possible errors, assigning different weight for each type
of errors) to judge the quality of process extraction from natural language text correctly?


5   Initial Research Plan
A promising possibility to investigate RQ1 in the task of process extraction from nat-
ural language text could be the adoption of the two steps transformation approach
with intermediate representation. This approach enables to tackle the linguistics chal-
lenges linked to process extraction incrementally and independently. In RQ1.1, process
4       P. Bellan

elements detection task is considered as a classification problem. The integration of
statistical classifiers in this framework could increase precision and recall of process
elements extracted, rejecting false positive. A strong limitation of rule-based approaches
is the impossibility of taking advantage of semantic embeddings vectors to represent
the meaning conveyed by a process description. Semantic embeddings together with a
statistical classifier should allow taking a possibly correct decision in those cases out
of any rules or word lists. The resulting framework should have the necessary general-
ization abilities to deal with multiple possible scenarios and different writing styles. In
RQ1.2, I would investigate the adoption of semantics embeddings as well as discover
which are the other possible important linguistic features that can increase classification
performance. The effectiveness of many linguistic features are still unexplored. Indeed,
there is a gap in the literature regarding the most predictive linguistics features to extract
to better detect (in a statistical setting) the process elements described. An example
of unconsidered liguistic features are: Multi-Words-Expressions (MWE), verb classes,
temporal expressions, and preposition super sense.
    The costly problem of creating a good resource of labeled data to train statistical
models (able to scale up in real scenarios) on, data augmentation techniques have to
be investigated in order to expand data availability. The difficulties related to this type
of data generation concern generating an artificial valid textual process description
with different words, different phrase structures, and possibly a different writing style,
without changing the semantic of the process model described in the original process
description. The study of this type of data augmentation would partially address L2.
    In RQ2, I would investigate the possibility of handling linguistics phenomena also by
leveraging models trained to solve similar tasks but in different contexts. Moreover, their
integration allows to consider a broader sets of features in process elements extraction
tasks. But, because target classes of pre-trained models (such as event classes of an event
detection system) could differ from the ones needed in these tasks, transfer learning
and domain adaptation techniques must to be considered. Together these point would
address L1.
    These research questions are all intended to solve the first sub-problem (fa ). They
have to be addressed before the investigations of better solutions to the sub-problems
of determine the logical succession of process model elements (fb ) can take place. This
is so, because it is vital that process elements are correctly extracted in the input text;
although the final diagrams will always be wrong.
    In RQ3, I would tackle the lack of a real comparison of different approaches on a
single real-world benchmark, because it should shed light on the real weaknesses and
strengths of the different research contributions. The metrics proposed in the literature
do not make a distinction between the possible kind of errors that can be generated.
For example, focusing on activities and participants only, there are no metrics that try
to quantify the amount of error if an activity is attributed to the wrong participant.
In a real-world context this kind of error can have significant negative consequences.
Thus, to fill the gap L3 and to also finally give uniformity to this research field, I would
investigate more realistic metrics able to weight for importance the different possible
errors related to process extraction from natural language text.
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