Rakenduste kasutajaarvustustest informatsiooni kaevandamine tarkvara arendustegevuste soodustamiseks

Kasutajate vajaduste ja ootuste hindamine on arendajate jaoks oluline oma tarkvararakenduste kvaliteedi parandamiseks. Mobiilirakenduste platvormidele sisestatud arvustused on kasulikuks infoallikaks kasutajate pidevalt muutuvate vajaduste hindamiseks. Igapäevaselt rakenduste platvormidele esitatud arvustuste suur maht nõuab aga automaatseid meetodeid neist kasuliku info leidmiseks. Arvustuste automaatseks liigitamiseks, nt veateatis või uue funktsionaalsuse küsimine, saab kasutada teksti klassifitseerimismudeleid. Rakenduse funktsioonide automaatne kaevandamine arvustustest aitab teha kokkuvõtteid kasutajate meelsusest rakenduse olemasolevate funktsioonide osas. Kõigepealt eksperimenteerime erinevate tekstiklassifitseerimise mudelitega ning võrdleme lihtsaid, leksikaalseid tunnuseid kasutavaid mudeleid keerukamatega, mis kasutavad rikkalikke lingvistilisi tunnuseid või mis põhinevad tehisnärvivõrkudel. Erinevate faktorite mõju uurimiseks funktsioonide kaevandamise meetoditele me teeme kõigepealt kindlaks erinevate meetodite baastaseme täpsuse rakendades neid samades eksperimentaalsetes tingimustes. Seejärel võrdleme neid meetodeid erinevates tingimustes, varieerides treenimiseks kasutatud annoteeritud andmestikke ning hindamismeetodeid. Kuna juhendatud masinõppel baseeruvad kaevandamismeetodid on võrreldes reeglipõhistega tundlikumad (1) andmete märgendamisel kasutatud annoteerimisjuhistele ning (2) märgendatatud andmestiku suurusele, siis uurisime nende faktorite mõju juhendatud masinõppe kontekstis ja pakkusime välja uued annoteerimisjuhised, mis võivad aidata funktsioonide kaevandamise täpsust parandada. Käesoleva doktoritöö projekti tulemusel valmis ka kontseptuaalne tööriist, mis võimaldab konkureerivaid rakendusi omavahel võrrelda. Tööriist kombineerib arvustuse tekstide klassifitseerimise ja rakenduse funktsioonide kaevandamise meetodid. Tööriista hinnanud kümme tarkvaraarendajat leidsid, et sellest võib olla kasu rakenduse kvaliteedi parandamiselFor app developers, it is important to continuously evaluate the needs and expectations of their users to improve app quality. User reviews submitted to app marketplaces are regarded as a useful information source to re-access evolving user needs. The large volume of user reviews received every day requires automatic methods to find such information in user reviews. Text classification models can be used to categorize review information into types such as feature requests and bug reports, while automatic app feature extraction from user reviews can help in summarizing users’ sentiments at the level of app features. For classifying review information, we perform experiments to compare the performance of simple models using only lexical features to models with rich linguistic features and models built on deep learning architectures, i.e., Convolutional Neural Network (CNN). To investigate factors influencing the performance of automatic app feature extraction methods, i.e. rule-based and supervised machine learning, we first establish a baseline in a single experimental setting and then compare the performances in different experimental settings (i.e., varying annotated datasets and evaluation methods). Since the performance of supervised feature extraction methods is more sensitive than rule- based methods to (1) guidelines used to annotate app features in user reviews and (2) the size of the annotated data, we investigate their impact on the performance of supervised feature extraction models and suggest new annotation guidelines that have the potential to improve feature extraction performance. To make the research results of the thesis project also applicable for non-experts, we developed a proof-of-concept tool for comparing competing apps. The tool combines review classification and app feature extraction methods and has been evaluated by ten developers from industry who perceived it useful for improving the app quality.  https://www.ester.ee/record=b529379

Mining app reviews to support software engineering

The thesis studies how mining app reviews can support software engineering. App reviews —short user reviews of an app in app stores— provide a potentially rich source of information to help software development teams maintain and evolve their products. Exploiting this information is however difficult due to the large number of reviews and the difficulty in extracting useful actionable information from short informal texts. A variety of app review mining techniques have been proposed to classify reviews and to extract information such as feature requests, bug descriptions, and user sentiments but the usefulness of these techniques in practice is still unknown. Research in this area has grown rapidly, resulting in a large number of scientific publications (at least 182 between 2010 and 2020) but nearly no independent evaluation and description of how diverse techniques fit together to support specific software engineering tasks have been performed so far. The thesis presents a series of contributions to address these limitations. We first report the findings of a systematic literature review in app review mining exposing the breadth and limitations of research in this area. Using findings from the literature review, we then present a reference model that relates features of app review mining tools to specific software engineering tasks supporting requirements engineering, software maintenance and evolution. We then present two additional contributions extending previous evaluations of app review mining techniques. We present a novel independent evaluation of opinion mining techniques using an annotated dataset created for our experiment. Our evaluation finds lower effectiveness than initially reported by the techniques authors. A final part of the thesis, evaluates approaches in searching for app reviews pertinent to a particular feature. The findings show a general purpose search technique is more effective than the state-of-the-art purpose-built app review mining techniques; and suggest their usefulness for requirements elicitation. Overall, the thesis contributes to improving the empirical evaluation of app review mining techniques and their application in software engineering practice. Researchers and developers of future app mining tools will benefit from the novel reference model, detailed experiments designs, and publicly available datasets presented in the thesis

B!SON: A Tool for Open Access Journal Recommendation

Finding a suitable open access journal to publish scientific work is a complex task: Researchers have to navigate a constantly growing number of journals, institutional agreements with publishers, funders’ conditions and the risk of Predatory Publishers. To help with these challenges, we introduce a web-based journal recommendation system called B!SON. It is developed based on a systematic requirements analysis, built on open data, gives publisher-independent recommendations and works across domains. It suggests open access journals based on title, abstract and references provided by the user. The recommendation quality has been evaluated using a large test set of 10,000 articles. Development by two German scientific libraries ensures the longevity of the project

Generation and Applications of Knowledge Graphs in Systems and Networks Biology

The acceleration in the generation of data in the biomedical domain has necessitated the use of computational approaches to assist in its interpretation. However, these approaches rely on the availability of high quality, structured, formalized biomedical knowledge. This thesis has the two goals to improve methods for curation and semantic data integration to generate high granularity biological knowledge graphs and to develop novel methods for using prior biological knowledge to propose new biological hypotheses. The first two publications describe an ecosystem for handling biological knowledge graphs encoded in the Biological Expression Language throughout the stages of curation, visualization, and analysis. Further, the second two publications describe the reproducible acquisition and integration of high-granularity knowledge with low contextual specificity from structured biological data sources on a massive scale and support the semi-automated curation of new content at high speed and precision. After building the ecosystem and acquiring content, the last three publications in this thesis demonstrate three different applications of biological knowledge graphs in modeling and simulation. The first demonstrates the use of agent-based modeling for simulation of neurodegenerative disease biomarker trajectories using biological knowledge graphs as priors. The second applies network representation learning to prioritize nodes in biological knowledge graphs based on corresponding experimental measurements to identify novel targets. Finally, the third uses biological knowledge graphs and develops algorithmics to deconvolute the mechanism of action of drugs, that could also serve to identify drug repositioning candidates. Ultimately, the this thesis lays the groundwork for production-level applications of drug repositioning algorithms and other knowledge-driven approaches to analyzing biomedical experiments

Toward Emotion Recognition From Physiological Signals in the Wild: Approaching the Methodological Issues in Real-Life Data Collection

Emotion, mood, and stress recognition (EMSR) has been studied in laboratory settings for decades. In particular, physiological signals are widely used to detect and classify affective states in lab conditions. However, physiological reactions to emotional stimuli have been found to differ in laboratory and natural settings. Thanks to recent technological progress (e.g., in wearables) the creation of EMSR systems for a large number of consumers during their everyday activities is increasingly possible. Therefore, datasets created in the wild are needed to insure the validity and the exploitability of EMSR models for real-life applications. In this paper, we initially present common techniques used in laboratory settings to induce emotions for the purpose of physiological dataset creation. Next, advantages and challenges of data collection in the wild are discussed. To assess the applicability of existing datasets to real-life applications, we propose a set of categories to guide and compare at a glance different methodologies used by researchers to collect such data. For this purpose, we also introduce a visual tool called Graphical Assessment of Real-life Application-Focused Emotional Dataset (GARAFED). In the last part of the paper, we apply the proposed tool to compare existing physiological datasets for EMSR in the wild and to show possible improvements and future directions of research. We wish for this paper and GARAFED to be used as guidelines for researchers and developers who aim at collecting affect-related data for real-life EMSR-based applications

Discovering Play Store Reviews Related to Specific Android App Issues

Mobile App reviews may contain information relevant to developers. Developers can investigate these reviews to see what users of their apps are complaining about. However, the huge volume of incoming reviews is impractical to analyze manually. Existing research that attempts to extract this information suffers from two major issues: supervised machine learning methods are usually pre-trained, and thus, does not provide the developers the freedom to define the app issue they are interested in, whereas unsupervised methods do not guarantee that a particular app issue topic will be discovered. In this thesis, we attempt to devise a framework that would allow developers to define topics related to app issues at any time, and with minimal effort, discover as many reviews related to the issue as possible. Scalable Continuous Active Learning (S-CAL) is an algorithm that can be used to quickly train a model to retrieve documents with high recall. First, we investigate whether S-CAL can be used as a tool for training models to retrieve reviews about a specific app issue. We also investigate whether a model trained to retrieve reviews about a specific issue for one app can be used to do the same for a separate app facing the same issue. We further investigate transfer learning methods to improve retrieval performance for the separate apps. Through a series of experiments, we show that S-CAL can be used to quickly train models that can to retrieve reviews about a particular issue. We show that developers can discover relevant information during the process of training the model and that the information discovered is more than the information that can be discovered using keyword search under similar time restrictions. Then, we show that models trained using S-CAL can indeed be reused for retrieving reviews for a separate app and that performing additional training using transfer learning protocols can improve performance for models that performed below expectation. Finally, we compare the performance of the models trained by S-CAL at retrieving reviews for a separate app against that of two state-of-the-art app review analysis methods one of which uses supervised learning, while the other uses unsupervised learning. We show that at the task of retrieving relevant reviews about a particular topic, models trained by S-CAL consistently outperform existing state-of-the-art methods

Understanding the behaviour and influence of automated social agents

Soft-bound submitted: Fri 23 Feb 2018 Corrections submitted: Mon 30 Jul 2018 Corrections approved: Tue 7 Aug 2018 Apollo submitted: Wed 22 Aug 2018 Hard-bound submitted: Fri 24 Aug 2018Online social networks (OSNs) have seen a remarkable rise in the presence of automated social agents, or social bots. Social bots are the new computing viral, that are surreptitious and clever. What facilitates the creation of social agents is the massive human user-base and business-supportive operating model of social networks. These automated agents are injected by agencies, brands, individuals, and corporations to serve their work and purpose; utilising them for news and emergency communication, marketing, social activism, political campaigning, and even spam and spreading malicious content. Their influence was recently substantiated by coordinated social hacking and computational political propaganda. The thesis of my dissertation argues that automated agents exercise a profound impact on OSNs that transforms into an array of influence on our society and systems. However, latent or veiled, these agents can be successfully detected through measurement, feature extraction and finely tuned supervised learning models. The various types of automated agents can be further unravelled through unsupervised machine learning and natural language processing, to formally inform the populace of their existence and impact.Sep'14-Aug'17, Marie Curie ITN METRICS, Early-Stage Researcher Sep'17, UMobile, Research Associate Oct'17-Mar'18, EPSRC Global Challenges Research Fund, Research Associat