=Paper= {{Paper |id=Vol-3672/PT-paper3 |storemode=property |title=RE-Miner: Mining Mobile User Reviews with Feature Extraction and Emotion Classification |pdfUrl=https://ceur-ws.org/Vol-3672/PT-paper3.pdf |volume=Vol-3672 |authors=Quim Motger,Max Tiessler,Marc Oriol,Irene Bertolín |dblpUrl=https://dblp.org/rec/conf/refsq/MotgerTOB24 }} ==RE-Miner: Mining Mobile User Reviews with Feature Extraction and Emotion Classification== https://ceur-ws.org/Vol-3672/PT-paper3.pdf
                                RE-Miner: Mining Mobile User Reviews with Feature
                                Extraction and Emotion Classification
                                Quim Motger1 , Max Tiessler1 , Marc Oriol1 and Irene Bertolín1
                                1
                                    Department of Service and Information System Engineering, Universitat Politècnica de Catalunya


                                                                         Abstract
                                                                         In the context of app stores, user reviews are pivotal on supporting multiple requirements engineering
                                                                         tasks. Among these, feature extraction and emotion classification play a crucial role in requirements pri-
                                                                         oritization, feedback gathering and release planning. Empirical evaluation of these techniques is impeded
                                                                         by data collection complexities and a lack of reproducible methods and available tools. Furthermore,
                                                                         existing studies often focus on isolated tasks, hindering a comprehensive analysis of user perceptions.
                                                                         This paper introduces RE-Miner, a work-in-progress tool integrating multiple feature extraction and
                                                                         emotion classification innovative methods, enabling a detailed analysis of feature-oriented user feedback.
                                                                         RE-Miner comprises a web-based service for task integration and comparison, and a web application for
                                                                         persistent storage and analytical visualization of reviews. As a result, RE-Miner provides a platform for
                                                                         seamless integration, replication, and comparison of review mining techniques, fostering advancements
                                                                         in feature extraction and emotion classification understanding for requirements engineering. A demo of
                                                                         the tool is showcased here: https://youtu.be/PFNCbborPuU.

                                                                         Keywords
                                                                         mobile app reviews, feature extraction, emotion classification, natural language processing




                                1. Introduction
                                User reviews offer a wealth of information to support multiple requirements engineering
                                tasks [1]. Elicitation of feature requests [2], identification of bugs or issues [3], user feedback
                                gathering and analysis [4], and release planning or prioritization [5] are a few examples of
                                the most popular use cases for automated review processing. Among these, feature extraction
                                (i.e., extracting mentions to functional aspects of an app [6]) and emotion classification (i.e.,
                                extracting the sentiments or emotions in a text [7]) are two of the most popular techniques.
                                While they have undergone intense study [8], innovations in the landscape of natural language
                                processing triggered by deep learning and large language models are promoting accuracy
                                improvements in both feature extraction [9] and emotion classification [10]. Meanwhile, some
                                challenges like disambiguation, domain-specific adaptation and precision of negative emotion
                                detection still remain [8].

                                In: D. Mendez, A. Moreira, J. Horkoff, T. Weyer, M. Daneva, M. Unterkalmsteiner, S. Bühne, J. Hehn, B. Penzenstadler, N.
                                Condori-Fernández, O. Dieste, R. Guizzardi, K. M. Habibullah, A. Perini, A. Susi, S. Abualhaija, C. Arora, D. Dell’Anna, A.
                                Ferrari, S. Ghanavati, F. Dalpiaz, J. Steghöfer, A. Rachmann, J. Gulden, A. Müller, M. Beck, D. Birkmeier, A. Herrmann,
                                P. Mennig, K. Schneider. Joint Proceedings of REFSQ-2024 Workshops, Doctoral Symposium, Posters & Tools Track, and
                                Education and Training Track. Co-located with REFSQ 2024. Winterthur, Switzerland, April 8, 2024.
                                $ joaquim.motger@upc.edu (Q. Motger); max.tiessler@upc.edu (M. Tiessler); marc.oriol@upc.edu (M. Oriol)
                                 0000-0002-4896-7515 (Q. Motger); 0000-0003-1928-7024 (M. Oriol)
                                                                       © 2024 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
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Quim Motger et al. CEUR Workshop Proceedings                                                    1–8


   Evaluating these methods poses scientific challenges like data collection [11], replication
and deployment of resource-intensive services [12]. Additionally, from a user perspective,
comparison and selection of the most suitable approach for a given domain is problematic,
undermined or even neglected [13]. Furthermore, most research is dedicated to the isolated
use of these tasks [8]. Combining feature and emotion descriptors allows a fine-granularity
analysis on the user perception to a particular feature or a cluster of features. This knowledge
is valuable to support single-feature emotion-oriented analysis and filtering of non-relevant
content [14]. While there is some existing work proposing a combined analysis of these tasks
(see Section 6), their replication is problematic due to the lack of open source tools and reusable
frameworks [8].
   This paper introduces RE-Miner, a work-in-progress software tool designed for replication
and comparative analysis in review-based feature extraction and emotion classification. RE-
Miner consists of a web-based service for integrating and comparing multiple review mining
tasks, and a web application to support the visual analysis of user reviews, incorporating
statistical data on the features and emotions derived from these reviews. We envisage that our
contribution will assist researchers and app stakeholders in the selection, replication, integration
and comparison of review mining techniques.


2. Background
While the field of natural language processing for requirements engineering (NLP4RE) is
not novel, availability of reusable tools or even full descriptions to allow replication of such
techniques is scarce. Zhao et al. surveyed 130 NLP4RE tools [13], from which only 17 were
available for download. Furthermore, they claimed this scarcity to be particularly highlighted
in novel NLP techniques and specialized tools integrating deep learning strategies.
   Focusing on feature extraction tasks, the SAFE tool is considered one of the standard methods,
based on syntactic-based pattern matching techniques complemented with semantic similarity
for feature candidate linking [6]. However, not only its accuracy in the analysis of reviews
is limited [15], but its source code is not available and its replication requires design assump-
tions [8]. Similar approaches like GuMa [14] and ReUS [16] also focus on syntactic aspects.
Beyond this formulation of the problem, KEFE proposes a deep learning classifier designed to
sift through syntactically extracted features and exclude non-relevant expressions [17].
   On the other hand, emotion classification aims at detecting the emotion in accordance with
a specified emotional model. This contrasts to traditional sentiment analysis techniques that
just aim at measuring the positive or negative orientation of a text [18]. In our proposal, we
have adopted one of the most widely embraced emotion models, proposed by P. Ekman [19].
This model classifies the emotions as: sadness, fear, happiness, anger, surprise, and disgust.
Complementary, the neutral feeling is also used for non-specific emotions. Automatic emotion
identification methods from textual content include lexicon-based techniques, classical machine
learning models (e.g. SVM, bayes,...) or deep learning models [18]. More recently, transformer-
based models and LLMs have significantly advanced the field of emotion classification [20].




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Quim Motger et al. CEUR Workshop Proceedings                                                                  1–8




Figure 1: RE-Miner architecture. External service integration is represented: (1) as a web-service built
from source code used through API communication; (2) as a model loaded from HuggingFace for
inference; or (3) as a fine-tuned model from OpenAI used through API communication.


3. Tool description
The main goal of RE-Miner is to provide a user-friendly, easily accessible and reusable software
tool for both researchers and mobile app developers. It is designed to facilitate replication
studies and comparative analyses in the field of review-based natural language processing
tasks, with a particular emphasis on feature extraction and emotion classification. The tool
is composed of two software-based contributions: (1) RE-Miner-Hub1 , a web-based service
supporting the integration and comparison of feature extraction and emotion classification
tasks, using various NLP models and providers; and (2) RE-Miner-Dashboard2 , a web-based
application to support user management, app and review persistence, automatic processing and
analytical visualization of a batch of user reviews combining features and emotions emerged
from these reviews. Figure 1 provides a high-level overview of RE-Miner architecture.

3.1. RE-Miner-Hub
RE-Miner-Hub is a web-service system designed to empower researchers with the capability to
conduct feature extraction and emotion classification tasks using a common API syntax. RE-
Miner-Hub serves as a centralized orchestration service of heterogeneous software components
(both from a logic and physical point of view), each of them deployed as decoupled, decentralized
software resources. This architecture facilitates re-usability of third-party methods, which can
extend RE-Miner set of tasks by either replicating and embedding these techniques as a new
RE-Miner software module or simply by using available services from the web. For feature
extraction, current version of RE-Miner-Hub employs two methods based on our previous work:

       • TransFeatEx integrates a RoBERTa-based pre-trained model used to leverage syntactic
         patterns and semantic annotations (e.g., polarity score) to identify feature expressions [21].
         TransFeatEx is developed as a Python-based web-service, and it is deployed as a standalone
         web application and accessed using HTTP-based communication through an API. We use
         its default configuration, as described in the tool repository and in the original paper [21].
       • T-FREX gives access to a suite of Transformer-based models (i.e., BERT, RoBERTa and
         XLNet) fine-tuned for Named-Entity Recognition using crowdsourced feature annotations
1
    Source code and API Swagger documentation available at: https://github.com/gessi-chatbots/RE-Miner-Hub.
2
    Source code and sample dataset available at: https://github.com/gessi-chatbots/RE-Miner-Dashboard.



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Quim Motger et al. CEUR Workshop Proceedings                                                                   1–8


          generated by users in software recommendation platforms [9]. T-FREX models are
          available on HuggingFace3 , allowing their integration by simply adding these models for
          inference through an NLP pipeline using the Transformers Python module.

      For emotion classification, we developed and employed the following methods:

       • Encoder Classifier focuses on fine-tuning encoder-only LLMs (i.e., BERT, BETO) with
         a document classification layer on top [22]. These models were fine-tuned using 2,000
         annotated user-generated microblogs (e.g., tweets). This component weights each emotion
         class, based on the probability distribution of a given review to reflect said property.
       • Generative Classifier utilizes a GPT-3.5-Turbo model fine-tuned on a few-shot learning
         setting using prompt engineering to extract emotions from mobile application reviews.
         We used a reduced sample dataset of 100 internally annotated app reviews for the fine-
         tuning process4 . Contrarily to the Encoder Classifier, the outcome of this method is
         restricted to the most probable emotion for a given review.

   For each task, users have the freedom to choose models that align with their preferences (i.e.,
context, dataset, computational resources...). RE-Miner-Hub exposes simple API methods to
perform both feature extraction and/or emotion classification on a batch of reviews.
   The modular design of RE-Miner-Hub provides flexibility in the list of available models,
enabling scalable integration of new models for both sentiment analysis and feature extraction
tasks. Moreover, within the RE-Miner ecosystem, a unified data model for reviews is used. This
ensures scalability when integrating other software components that operate with the same
data model. Lastly, the Hub acts as a flexible middle-ware between the RE-Miner-Dashboard
and various third-party APIs and software components. The only requirement for integrating
a new model into the RE-Miner-Hub is that it must be accessible via API (either the Hugging
Face inference API or a traditional REST API).

3.2. RE-Miner-Dashboard
The RE-Miner-Dashboard is primarily designed as a visualization and analytical software
component. The dashboard, encompasses several key components: (1) a React front-end
application; (2) an authorization and authentication system; (3) an API Gateway responsible
for managing the access to the APIs; (4) a backend consisting of two APIs (handling reviews
and mobile apps, respectively) and a module dedicated to creating new user entities within the
database; and (5) a NoSQL document-based database.
   Upon user creation and the corresponding database entry, access permissions to the appli-
cation and associated APIs are granted. Users can upload individual applications or batches
of them, along with the reviews, which are then stored in the database. When users want to
analyze a review or a batch of reviews, the RE-Miner-Dashboard application sends a request
to the RE-Miner-Hub, specifying the task (e.g. feature extraction and/or sentiment analysis).
When receiving results from the RE-Miner-Hub system, they are stored in the database. This
3
    E.g.: https://huggingface.co/quim-motger/t-frex-bert-base-uncased (T-FREX models are referenced in model card).
4
    Prompt is available in GitHub repository. Full evaluation is yet to be conducted as depicted in Section 5.



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Quim Motger et al. CEUR Workshop Proceedings                                                     1–8




Figure 2: RE-Miner-Dashboard, including review analysis (left) and features/emotions chart (right).


seamless integration empowers users to use the analytical dashboard for engaging visual analy-
ses of their data, extracting meaningful insights from the reviews. Details on the use cases and
RE-Miner-Dashboard views are showcased in Section 4.


4. User workflow
The RE-Miner-Dashboard presents two main use cases for review analysis. These require users
to have completed the sign-up, login and upload of apps and reviews. Figure 2 illustrates a
snapshot of both use cases.
   1. Single-review analysis
        a) Users can select a review for analysis from the Reviews > View Reviews tab. Initiation
           of the analysis process can be done by clicking the Process review button.
        b) A modal wizard appears, guiding the user through the following steps:
              i. The user selects the task/s and the method used for each task (e.g., GPT-3.5 for
                 emotion classification; T-FREX BERT base for feature extraction).
             ii. The reviews are submitted to the RE-Miner-Hub to initiate the review analysis.
        c) After analysis, an icon will appear next to the processed review. By clicking it,
           the user opens the Review Analyzer view, displaying the analysis results, including
           detected emotions, emotion-marked sentences, and identified features within the
           review text.
   2. Batch-review analysis and visual analytics
        a) The user should repeat steps 1.a) and 1.b) while selecting multiple (or all) uploaded
           app reviews.
        b) By navigating to the Dashboard tab, the following analytical charts can be found:
              i. Sentiment Polar Area: aggregated sum of each emotion across all reviews.
             ii. Top Features Histogram: aggregated sum of the most frequent extracted features.
            iii. Features Over Time Chart: distribution of feature mentions over a time window.
            iv. Sentiment Histogram: distribution of emotions (displayed in a stacked layout
                 based on frequency for each emotion class) over a time window.
             v. Features/Emotions Chart: combined distribution of a set of feature mentions
                 with their associated emotions over a time window.



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Quim Motger et al. CEUR Workshop Proceedings                                                     1–8


5. Evaluation plan
Below we summarize the main steps of the planned (and ongoing) evaluation:

    • Data collection and annotation. We built on our previous work on mobile app reposi-
      tory mining to collect multiple reviews for a given domain [23], filtered and refined for the
      feature extraction task [9]. This dataset consists of 468 apps with 23,816 reviews within a 1
      year time window, each with at least 1 crowdsourced annotated feature. We used a subset
      of this data set to showcase the different use cases of RE-Miner as depicted in Section 4
      and in the video demonstration. For emotion classification, we plan on conducting an
      internal iterative annotation process of a subset of reviews through structured guidelines,
      measuring annotation agreement and establishing solid evaluation criteria.
    • Experimentation. We plan to conduct an empirical evaluation of all methods in Sec-
      tion 3.1 by combining multiple cross-validation analyses using the complete data set
      annotated with features and emotions. This entails quantitative ground-truth evaluation
      to assess and compare the effectiveness of each technique. Additionally, we intend to
      apply search-based algorithms (e.g., clustering) to infer how the aggregated analysis of
      features and emotions can support requirements engineering tasks. For assessing the
      overall software product quality of the tool, we will focus on performance efficiency and
      usability as defined in ISO/IEC 25010 [24]. For performance efficiency, we will measure the
      tool’s response time and scalability under varying workloads for data upload and feature
      and emotion extraction tasks. For usability assessment, we plan to conduct user studies
      to evaluate ease of interaction, explainability of results, and overall user satisfaction with
      potential stakeholders.


6. Related work
Da̧browski et al. recently concluded that automated combined analysis of feature extraction and
emotion classification is limited, especially in the use of innovative NLP techniques [1]. Guzman
and Maleej described a syntactic and semantic based technique combining feature extraction
with lexicon-based polarity extraction on a sentence-level [14]. This process is consolidated
through an LDA topic modelling method to infer high-level features and average sentiments
(i.e., positive vs. negative). A similar approach is depicted by Dragoni et al. [16], depicting
a pipeline for the streamlined automated collection and analysis of user reviews to extract a
normalized polarity score. Beyond methods surveyed by Da̧browski et al. [1], Gunaratman et al.
propose an automated app rating mechanism by weighting features and associated sentiments
on a feature level [25]. Finally, TransFeatEx integrates a sentiment analysis filter, whose use is
limited to filtering out extremely polarized reviews to avoid biased representation [21].
    In comparison with RE-Miner, main limitations of these approaches include: (1) unavail-
ability of full source code or distributed software; (2) limitations for full replication; (3) use of
traditional NLP techniques with respect to innovative methods; and (4) lack of data analytics
visualization beyond finer granularity analysis on a review level. To overcome these limitations,
RE-Miner software components are distributed including source code and packaged web ser-
vices. README files include instructions to install, deploy and integrate these components, as



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Quim Motger et al. CEUR Workshop Proceedings                                                   1–8


well as a sample dataset to replicate the demo depicted in Section 4. Finally, while RE-Miner
does not exclude the use of traditional NLP methods, the current version integrates multiple
Transformer-based approaches for both feature extraction and sentiment analysis tasks.


7. Conclusions and future work
RE-Miner contributions are three-fold. First, we aim at providing a reusable tool to facilitate
integration and extension of NLP4RE tasks in the context of app review mining. Second, we
distribute software components as source code and as a standalone web application to integrate
and run review mining processes to analyze the output of these methods on a fine granularity
(i.e., review and sentence level) basis. Finally, we introduce a sample of simple data analytics to
support and evolve the evolution of a dashboard to visualize statistics on review descriptors
(i.e., features and emotions), both in isolation and combined.
    As ongoing future work, we are working on extending the analytical dashboard with clustering
and topic modelling techniques to provide higher levels of abstraction of clusters of features
and emotions. This visualization will be used to support user trend analysis, involving dense
centroids associated to a particular emotion or set of features. As a next action point, we plan
to extend current tasks by including content classification of these reviews as an additional
descriptor, focused on topic modelling and type of review (e.g., feature request, bug report,
praise...). Finally, from a maintainability perspective, we plan on extending each task with new
methods in the field, to facilitate replication studies following open-science principles.


Acknowledgments
With the support from the Secretariat for Universities and Research of the Ministry of Business
and Knowledge of the Government of Catalonia and the European Social Fund. This paper has
been funded by the Spanish Ministerio de Ciencia e Innovación under project / funding scheme
PID2020-117191RB-I00 / AEI/10.13039/501100011033.


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