The role of geographic knowledge in sub-city level geolocation algorithms

Geolocation of microblog messages has been largely investigated in the lit- erature. Many solutions have been proposed that achieve good results at the city-level. Existing approaches are mainly data-driven (i.e., they rely on a training phase). However, the development of algorithms for geolocation at sub-city level is still an open problem also due to the absence of good training datasets. In this thesis, we investigate the role that external geographic know- ledge can play in geolocation approaches. We show how di)erent geographical data sources can be combined with a semantic layer to achieve reasonably accurate sub-city level geolocation. Moreover, we propose a knowledge-based method, called Sherloc, to accurately geolocate messages at sub-city level, by exploiting the presence in the message of toponyms possibly referring to the speci*c places in the target geographical area. Sherloc exploits the semantics associated with toponyms contained in gazetteers and embeds them into a metric space that captures the semantic distance among them. This allows toponyms to be represented as points and indexed by a spatial access method, allowing us to identify the semantically closest terms to a microblog message, that also form a cluster with respect to their spatial locations. In contrast to state-of-the-art methods, Sherloc requires no prior training, it is not limited to geolocating on a *xed spatial grid and it experimentally demonstrated its ability to infer the location at sub-city level with higher accuracy

Introduction to the second international symposium of platial information science

People ‘live’ and constitute places every day through recurrent practices and experience. Our everyday lives, however, are complex, and so are places. In contrast to abstract space, the way people experience places includes a range of aspects like physical setting, meaning, and emotional attachment. This inherent complexity requires researchers to investigate the concept of place from a variety of viewpoints. The formal representation of place – a major goal in GIScience related to place – is no exception and can only be successfully addressed if we consider geographical, psychological, anthropological, sociological, cognitive, and other perspectives. This year’s symposium brings together place-based researchers from different disciplines to discuss the current state of platial research. Therefore, this volume contains contributions from a range of fields including geography, psychology, cognitive science, linguistics, and cartography

Predicting Building Functions by Fusing Social Media and Remote Sensing Data

Die Funktionen von Gebäuden lassen sich nicht direkt messen, sondern erfordern die Interpretation von Daten. In dieser Arbeit werden drei neue Methoden zur Vorhersage von Gebäudefunktionen vorgestellt, die auf Daten aus sozialen Medien und Fernerkundungsdaten beruhen. Die Methoden basieren auf Ansätzen des maschinellen Lernens und wurden auf kulturell diversifizierten Datensätzen entwickelt und getestet. Die Vorhersage lässt sich durch die Kombination mehrerer Modelle um bis zu 6,9% erhöhen

Content-aware Location Inference and Misinformation in Online Social Networks

Location inference is of potential use in the area of cybercrime prevention and misinformation detection. Inferring locations from user texts in Online Social Networks (OSN) is a non-trivial and challenging problem with regards to public safety. This work proposes LOCINFER - a novel non-uniform grid-based approach for location inference from Twitter messages using Quadtree spatial partitions. The proposed algorithm uses natural language processing (NLP) for semantic understanding and incorporates hybrid similarity measures for feature vector extraction and dimensionality reduction. LOCINFER addresses the sparsity problem which may be associated with training data following a biased clustering approach where densely populated regions within the data are partitioned into larger grids. The clustered grids are then classi�ed using a logistic regression model. The proposed method performed better than the state-of-the art in grid-based content-only location inference by more than 150km in Average Error Distance (AED) and almost 300km in Median Error Distance (MED). It also performed better than by 24% in terms of accuracy at 161km. It was 400km better in prediction for MED and 250km better in terms of AED. Also proposed is SENTDETECT - a technique that detects and classi�es fake news messages from Twitter posts using extensive experiments with machine learning and deep learning models including those without prior knowledge of the domain. Following a text-only approach, SENTDETECT utilises an additional feature of the word sentiments alongside the original text of the messages. Incorporating these engineered features into the feature vector, provides an enrichment of the vector space prior to the deep learning classi�cation task which utilised a Hierarchical Attention Networks (HAN) in pre-trained word embedding. An emotional word ratio (EMORATIO) was deduced following the discovery of a positive relationship between negative emotional words and fake news posts. Finally, the work aimed to perform automatic detection of misinformation posts and rumors. A lot of work has been done in the area of detecting the truthfulness or veracity of posts from OSN messages. This work presents a novel feature-augmented approach using both text and sentiments in enriching features used during prediction. The end result performed better by up to 40% in Recall and F-Measure over the state of the art on benchmark misinformation PHEME dataset which relied on textual features only. The blend of location inference with misinformation detection provides an e�ective tool in the �ght against vices on social media such as curtailing hate speech propagation, cyberbullying and fake news posts

Proceedings of the Fifth Italian Conference on Computational Linguistics CLiC-it 2018 : 10-12 December 2018, Torino

On behalf of the Program Committee, a very warm welcome to the Fifth Italian Conference on Computational Linguistics (CLiC-­‐it 2018). This edition of the conference is held in Torino. The conference is locally organised by the University of Torino and hosted into its prestigious main lecture hall “Cavallerizza Reale”. The CLiC-­‐it conference series is an initiative of the Italian Association for Computational Linguistics (AILC) which, after five years of activity, has clearly established itself as the premier national forum for research and development in the fields of Computational Linguistics and Natural Language Processing, where leading researchers and practitioners from academia and industry meet to share their research results, experiences, and challenges

Information Refinement Technologies for Crisis Informatics: User Expectations and Design Implications for Social Media and Mobile Apps in Crises

In the past 20 years, mobile technologies and social media have not only been established in everyday life, but also in crises, disasters, and emergencies. Especially large-scale events, such as 2012 Hurricane Sandy or the 2013 European Floods, showed that citizens are not passive victims but active participants utilizing mobile and social information and communication technologies (ICT) for crisis response (Reuter, Hughes, et al., 2018). Accordingly, the research field of crisis informatics emerged as a multidisciplinary field which combines computing and social science knowledge of disasters and is rooted in disciplines such as human-computer interaction (HCI), computer science (CS), computer supported cooperative work (CSCW), and information systems (IS). While citizens use personal ICT to respond to a disaster to cope with uncertainty, emergency services such as fire and police departments started using available online data to increase situational awareness and improve decision making for a better crisis response (Palen & Anderson, 2016). When looking at even larger crises, such as the ongoing COVID-19 pandemic, it becomes apparent the challenges of crisis informatics are amplified (Xie et al., 2020). Notably, information is often not available in perfect shape to assist crisis response: the dissemination of high-volume, heterogeneous and highly semantic data by citizens, often referred to as big social data (Olshannikova et al., 2017), poses challenges for emergency services in terms of access, quality and quantity of information. In order to achieve situational awareness or even actionable information, meaning the right information for the right person at the right time (Zade et al., 2018), information must be refined according to event-based factors, organizational requirements, societal boundary conditions and technical feasibility. In order to research the topic of information refinement, this dissertation combines the methodological framework of design case studies (Wulf et al., 2011) with principles of design science research (Hevner et al., 2004). These extended design case studies consist of four phases, each contributing to research with distinct results. This thesis first reviews existing research on use, role, and perception patterns in crisis informatics, emphasizing the increasing potentials of public participation in crisis response using social media. Then, empirical studies conducted with the German population reveal positive attitudes and increasing use of mobile and social technologies during crises, but also highlight barriers of use and expectations towards emergency services to monitor and interact in media. The findings led to the design of innovative ICT artefacts, including visual guidelines for citizens’ use of social media in emergencies (SMG), an emergency service web interface for aggregating mobile and social data (ESI), an efficient algorithm for detecting relevant information in social media (SMO), and a mobile app for bidirectional communication between emergency services and citizens (112.social). The evaluation of artefacts involved the participation of end-users in the application field of crisis management, pointing out potentials for future improvements and research potentials. The thesis concludes with a framework on information refinement for crisis informatics, integrating event-based, organizational, societal, and technological perspectives