Formalization and preliminary evaluation of a pipeline for text extraction from infographics

We propose a pipeline for text extraction from infographics that makes use of a novel combination of data mining and computer vision techniques. The pipeline defines a sequence of steps to identify characters, cluster them into text lines, determine their rotation angle, and apply state-of-the-art OCR to recognise the text. In this paper, we formally define the pipeline and present its current implementation. In addition, we have conducted preliminary evaluations over a data corpus of 121 manually annotated infographics from a broad range of illustration types such as bar charts, pie charts, and line charts, maps, and others. We assess the results of our text extraction pipeline by comparing it with two baselines. Finally, we sketch an outline for future work and possibilities for improving the pipeline

A systematic comparison of different approaches of unsupervised extraction of text from scholary figures

Different approaches have been proposed in the past to address the challenge of extracting text from scholarly figures. However, so far a comparative evaluation of the different approaches has not been conducted. Based on an extensive study, we compare the 7 most relevant approaches described in the literature as well as 25 systematic combinations of methods for extracting text from scholarly figures. To this end, we define a generic pipeline, consisting of six individual steps. We map the existing approaches to this pipeline and re-implement their methods for each pipeline step. The method-wise re-implementation allows to freely combine the different possible methods for each pipeline step. Overall, we have evaluated 32 different pipeline configurations and systematically compared the different methods and approaches. We evaluate the pipeline configurations over four datasets of scholarly figures of different origin and characteristics. The quality of the extraction results is assessed using F-measure and Levenshtein distance. In addition, we measure the runtime performance. The experimental results show that there is an approach that overall shows the best text extraction quality on all datasets. Regarding runtime, we observe huge differences from very fast approaches to those running for several weeks

Analysis and Modular Approach for Text Extraction from Scientific Figures on Limited Data

Scientific figures are widely used as compact, comprehensible representations of important information. The re-usability of these figures is however limited, as one can rarely search directly for them, since they are mostly indexing by their surrounding text (e. g., publication or website) which often does not contain the full-message of the figure. In this thesis, the focus is on making the content of scientific figures accessible by extracting the text from these figures. A modular pipeline for unsupervised text extraction from scientific figures, based on a thorough analysis of the literature, was built to address the problem. This modular pipeline was used to build several unsupervised approaches, to evaluate different methods from the literature and new methods and method combinations. Some supervised approaches were built as well for comparison. One challenge, while evaluating the approaches, was the lack of annotated data, which especially needed to be considered when building the supervised approach. Three existing datasets were used for evaluation as well as two datasets of 241 scientific figures which were manually created and annotated. Additionally, two existing datasets for text extraction from other types of images were used for pretraining the supervised approach. Several experiments showed the superiority of the unsupervised pipeline over common Optical Character Recognition engines and identified the best unsupervised approach. This unsupervised approach was compared with the best supervised approach, which, despite of the limited amount of training data available, clearly outperformed the unsupervised approach.Infografiken sind ein viel verwendetes Medium zur kompakten Darstellung von Kernaussagen. Die Nachnutzbarkeit dieser Abbildungen ist jedoch häufig limitiert, da sie schlecht auffindbar sind, da sie meist über die umschließenden Medien, wie beispielsweise Publikationen oder Webseiten, und nicht über ihren Inhalt indexiert sind. Der Fokus dieser Arbeit liegt auf der Extraktion der textuellen Inhalte aus Infografiken, um deren Inhalt zu erschließen. Ausgehend von einer umfangreichen Analyse verwandter Arbeiten, wurde ein generalisierender, modularer Ansatz für die unüberwachte Textextraktion aus wissenschaftlichen Abbildungen entwickelt. Mit diesem modularen Ansatz wurden mehrere unüberwachte Ansätze und daneben auch noch einige überwachte Ansätze umgesetzt, um diverse Methoden aus der Literatur sowie neue und bisher noch nicht genutzte Methoden zu vergleichen. Eine Herausforderung bei der Evaluation war die geringe Menge an annotierten Abbildungen, was insbesondere beim überwachten Ansatz Methoden berücksichtigt werden musste. Für die Evaluation wurden drei existierende Datensätze verwendet und zudem wurden zusätzlich zwei Datensätze mit insgesamt 241 Infografiken erstellt und mit den nötigen Informationen annotiert, sodass insgesamt 5 Datensätze für die Evaluation verwendet werden konnten. Für das Pre-Training des überwachten Ansatzes wurden zudem zwei Datensätze aus verwandten Textextraktionsbereichen verwendet. In verschiedenen Experimenten wird gezeigt, dass der unüberwachte Ansatz besser funktioniert als klassische Texterkennungsverfahren und es wird aus den verschiedenen unüberwachten Ansätzen der beste ermittelt. Dieser unüberwachte Ansatz wird mit dem überwachten Ansatz verglichen, der trotz begrenzter Trainingsdaten die besten Ergebnisse liefert

Casual Information Visualization on Exploring Spatiotemporal Data

The goal of this thesis is to study how the diverse data on the Web which are familiar to everyone can be visualized, and with a special consideration on their spatial and temporal information. We introduce novel approaches and visualization techniques dealing with different types of data contents: interactively browsing large amount of tags linking with geospace and time, navigating and locating spatiotemporal photos or videos in collections, and especially, providing visual supports for the exploration of diverse Web contents on arbitrary webpages in terms of augmented Web browsing

AI for social good: social media mining of migration discourse

The number of international migrants has steadily increased over the years, and it has become one of the pressing issues in today’s globalized world. Our bibliometric review of around 400 articles on Scopus platform indicates an increased interest in migration-related research in recent times but the extant research is scattered at best. AI-based opinion mining research has predominantly noted negative sentiments across various social media platforms. Additionally, we note that prior studies have mostly considered social media data in the context of a particular event or a specific context. These studies offered a nuanced view of the societal opinions regarding that specific event, but this approach might miss the forest for the trees. Hence, this dissertation makes an attempt to go beyond simplistic opinion mining to identify various latent themes of migrant-related social media discourse. The first essay draws insights from the social psychology literature to investigate two facets of Twitter discourse, i.e., perceptions about migrants and behaviors toward migrants. We identified two prevailing perceptions (i.e., sympathy and antipathy) and two dominant behaviors (i.e., solidarity and animosity) of social media users toward migrants. Additionally, this essay has also fine-tuned the binary hate speech detection task, specifically in the context of migrants, by highlighting the granular differences between the perceptual and behavioral aspects of hate speech. The second essay investigates the journey of migrants or refugees from their home to the host country. We draw insights from Gennep's seminal book, i.e., Les Rites de Passage, to identify four phases of their journey: Arrival of Refugees, Temporal stay at Asylums, Rehabilitation, and Integration of Refugees into the host nation. We consider multimodal tweets for this essay. We find that our proposed theoretical framework was relevant for the 2022 Ukrainian refugee crisis – as a use-case. Our third essay points out that a limited sample of annotated data does not provide insights regarding the prevailing societal-level opinions. Hence, this essay employs unsupervised approaches on large-scale societal datasets to explore the prevailing societal-level sentiments on YouTube platform. Specifically, it probes whether negative comments about migrants get endorsed by other users. If yes, does it depend on who the migrants are – especially if they are cultural others? To address these questions, we consider two datasets: YouTube comments before the 2022 Ukrainian refugee crisis, and during the crisis. Second dataset confirms the Cultural Us hypothesis, and our findings are inconclusive for the first dataset. Our final or fourth essay probes social integration of migrants. The first part of this essay probed the unheard and faint voices of migrants to understand their struggle to settle down in the host economy. The second part of this chapter explored the viability of social media platforms as a viable alternative to expensive commercial job portals for vulnerable migrants. Finally, in our concluding chapter, we elucidated the potential of explainable AI, and briefly pointed out the inherent biases of transformer-based models in the context of migrant-related discourse. To sum up, the importance of migration was recognized as one of the essential topics in the United Nation’s Sustainable Development Goals (SDGs). Thus, this dissertation has attempted to make an incremental contribution to the AI for Social Good discourse

The European electricity market over the last 10 years : Which major changes occurred in the electricity markets, in particular in the electricity production of the European Union, in the past 10 years and what are the implications for the future?

Electricity forms the backbone of modern society and is vital for powering industries, fostering innovations and guaranteeing the functioning of essential services and technologies. Throughout the last few decades, the usage of electricity has risen exponentially and is forecasted to grow for the foreseeable future. This underscores the need for functioning electricity markets all around the globe. In the European context, electricity markets have been moving towards integration and the ultimate goal is to create a common European electricity market. This thesis aims to investigate the major changes undergone by European electricity markets over the last 10 years and showcase some of the recent events that have had a major impact on the European electricity markets. Consequently, implications for the future of European electricity markets will be discussed. Both a literature review aimed at evaluating shifts in the overall market design and mechanisms as well an analysis showing the changes in price and electricity production over the last 10 years were performed. Our findings suggest that during the analysed timeframe major changes occurred in the type of electricity produced. The introduction of new market mechanisms such as flow-based market coupling and a trend towards decentralization and utilizing IT technologies to leverage data such as the smart grid have changed the face of the European electricity markets. Major increases in electricity prices, further enforced by the current Russian invasion of Ukraine have moved the focus of market actors towards security of supply and affordability. It is likely that these developments will substantially impact the current market design and the way the EU transitions to a carbon-neutral market. Avenues for further research might include: Research that goes further back in time Evaluating the ideal market design for the European electricity market Performing in-depth regression analysis of price coupling between electricity prices and other variables such as gas prices, ETS prices, …nhhma

Improving GPs' knowledge of the benefits and harms of treatment to support decision making in multimorbidity: qualitative research and co-design of a novel electronic information resource

Background General practitioners (GPs) regularly prescribe prolonged treatments for long-term conditions. However, GPs may benefit from further understanding of the absolute benefits and harms of these treatments, enhancing their ability to engage in shared decision-making and manage multimorbidity and polypharmacy. Aim To produce and evaluate a website to provide information on the benefits and harms of treatments for long-term conditions in a way that can be understood by GPs and potentially integrated into their practice. Methods The study consisted of three parts. First, a qualitative interview study and framework analysis with GPs exploring their attitudes to and understanding of the quantitative benefits and harms of treatments. Second, a participatory co-design process to design the website, coupled with a pragmatic approach to evidence collation to provide clinical content. Finally, an exploratory evaluation study of the website using online focus groups. Results The interview study reported findings on GPs’ understanding of quantitative information on the benefits and harms of treatments which informed the co-design research. The co-design research resulted in the creation of a website, www.gpevidence.org, which presents complex scientific information on treatment effect sizes and the nature and quality of the relevant clinical evidence. The evaluation study showed that participating GPs were able to understand the clinical information on GP Evidence, and that in hypothetical scenarios this might change their prescribing practice. Some participants found some information confusing. There was limited evidence that this new information could be integrated into complex decision-making for multimorbidity and polypharmacy. Conclusion The aim of producing a website able to deliver information on the benefits and harms of treatments for long-term conditions to GPs was achieved. Further research is needed to evaluate the effect of GP Evidence in real-world practice

Natural and Technological Hazards in Urban Areas

Natural hazard events and technological accidents are separate causes of environmental impacts. Natural hazards are physical phenomena active in geological times, whereas technological hazards result from actions or facilities created by humans. In our time, combined natural and man-made hazards have been induced. Overpopulation and urban development in areas prone to natural hazards increase the impact of natural disasters worldwide. Additionally, urban areas are frequently characterized by intense industrial activity and rapid, poorly planned growth that threatens the environment and degrades the quality of life. Therefore, proper urban planning is crucial to minimize fatalities and reduce the environmental and economic impacts that accompany both natural and technological hazardous events

Analysis and Concealment of Malware in an Adversarial Environment

Nowadays, users and devices are rapidly growing, and there is a massive migration of data and infrastructure from physical systems to virtual ones. Moreover, people are always connected and deeply dependent on information and communications. Thanks to the massive growth of Internet of Things applications, this phenomenon also affects everyday objects such as home appliances and vehicles. This extensive interconnection implies a significant rate of potential security threats for systems, devices, and virtual identities. For this reason, malware detection and analysis is one of the most critical security topics. The used detection strategies are well suited to analyze and respond to potential threats, but they are vulnerable and can be bypassed under specific conditions. In light of this scenario, this thesis highlights the existent detection strategies and how it is possible to deceive them using malicious contents concealment strategies, such as code obfuscation and adversarial attacks. Moreover, the ultimate goal is to explore new viable ways to detect and analyze embedded malware and study the feasibility of generating adversarial attacks. In line with these two goals, in this thesis, I present two research contributions. The first one proposes a new viable way to detect and analyze the malicious contents inside Microsoft Office documents (even when concealed). The second one proposes a study about the feasibility of generating Android malicious applications capable of bypassing a real-world detection system. Firstly, I present Oblivion, a static and dynamic system for large-scale analysis of Office documents with embedded (and most of the time concealed) malicious contents. Oblivion performs instrumentation of the code and executes the Office documents in a virtualized environment to de-obfuscate and reconstruct their behavior. In particular, Oblivion can systematically extract embedded PowerShell and non-PowerShell attacks and reconstruct the employed obfuscation strategies. This research work aims to provide a scalable system that allows analysts to go beyond simple malware detection by performing a real, in-depth inspection of macros. To evaluate the system, a large-scale analysis of more than 40,000 Office documents has been performed. The attained results show that Oblivion can efficiently de-obfuscate malicious macro-files by revealing a large corpus of PowerShell and non-PowerShell attacks in a short amount of time. Then, the focus is on presenting an Android adversarial attack framework. This research work aims to understand the feasibility of generating adversarial samples specifically through the injection of Android system API calls only. In particular, the constraints necessary to generate actual adversarial samples are discussed. To evaluate the system, I employ an interpretability technique to assess the impact of specific API calls on the evasion. It is also assessed the vulnerability of the used detection system against mimicry and random noise attacks. Finally, it is proposed a basic implementation to generate concrete and working adversarial samples. The attained results suggest that injecting system API calls could be a viable strategy for attackers to generate concrete adversarial samples. This thesis aims to improve the security landscape in both the research and industrial world by exploring a hot security topic and proposing two novel research works about embedded malware. The main conclusion of this research experience is that systems and devices can be secured with the most robust security processes. At the same time, it is fundamental to improve user awareness and education in detecting and preventing possible attempts of malicious infections