Andreas Hotho - Böcker

Social Tagging Systems are web applications in which users upload resources (e.g., bookmarks, videos, photos, etc.) and annotate it with a list of freely chosen keywords called tags. This is a grassroots approach to organize a site and help users to find the resources they are interested in. Social tagging systems are open and inherently social; features that have been proven to encourage participation. However, with the large popularity of these systems and the increasing amount of user-contributed content, information overload rapidly becomes an issue. Recommender Systems are well known applications for increasing the level of relevant content over the “noise” that continuously grows as more and more content becomes available online. In social tagging systems, however, we face new challenges. While in classic recommender systems the mode of recommendation is basically the resource, in social tagging systems there are three possible modes of recommendation: users, resources, or tags. Therefore suitable methods that properly exploit the different dimensions of social tagging systems data are needed. In this book, we survey the most recent and state-of-the-art work about a whole new generation of recommender systems built to serve social tagging systems. The book is divided into self-contained chapters covering the background material on social tagging systems and recommender systems to the more advanced techniques like the ones based on tensor factorization and graph-based models.

The three volume proceedings LNAI 11906 – 11908 constitutes the refereed proceedings of the European Conference on Machine Learning and Knowledge Discovery in Databases, ECML PKDD 2019, held in Würzburg, Germany, in September 2019.The total of 130 regular papers presented in these volumes was carefully reviewed and selected from 733 submissions;

The three volume proceedings LNAI 11906 – 11908 constitutes the refereed proceedings of the European Conference on Machine Learning and Knowledge Discovery in Databases, ECML PKDD 2019, held in Würzburg, Germany, in September 2019.The total of 130 regular papers presented in these volumes was carefully reviewed and selected from 733 submissions;

The three volume proceedings LNAI 11906 – 11908 constitutes the refereed proceedings of the European Conference on Machine Learning and Knowledge Discovery in Databases, ECML PKDD 2019, held in Würzburg, Germany, in September 2019.The total of 130 regular papers presented in these volumes was carefully reviewed and selected from 733 submissions;

This book constitutes the proceedings of the 20th International Semantic Web Conference, ISWC 2021, which took place in October 2021.

This book constitutes the proceedings of the 47th German Conference on AI, KI 2024, which was held in Würzburg, Germany, during September 25–27, 2024. The 19 full papers, 7 short papers and 5 other papers presented in this book were carefully reviewed and selected from 63 submissions.

This book introduces and reviews recent advances inthe field in a comprehensive and non-technical way by focusing on the potentialof emerging citizen-science and social-computation frameworks, coupled with thelatest theoretical and modeling tools developed by physicists, mathematicians,computer and social scientists to analyse, interpret and visualize complex datasets.There is overwhelming evidence that the currentorganisation of our economies and societies is seriously damaging biologicalecosystems and human living conditions in the short term, with potentiallycatastrophic effects in the long term. The need to re-organise the dailyactivities with the greatest impact – energy consumption, transport, housing –towards a more efficient and sustainable development model has recently beenraised in the public debate on several global, environmental issues. Above all,this requires the mismatch between global, societal and individual needs to beaddressed. Recent advancesin Information and Communication Technologies (ICT)can trigger important transitions at the individual and collective level toachieve this aim.Based on the findings of the collaborative researchnetwork EveryAware the following developments among the emerging ICTtechnologies are discussed in depth in this volume:• Participatory sensing – where ICT development ispushed to the level where it can supportinformed action at the hyperlocal scale, providing capabilities forenvironmental monitoring, data aggregation and mining, as well as informationpresentation and sharing.• Web gaming, social computing and internet-mediatedcollaboration – where the Web will continue to acquire the status of aninfrastructure for social computing, allowing users’ cognitive abilities to becoordinated in online communities, and steering the collective action towardspredefined goals.• Collective awareness and decision-making – where theaccess to both personal and community data, collected by users, processed withsuitable analysis tools, and re-presented in an appropriate format by usablecommunication interfaces leads to a bottom-up development of collective socialstrategies.

This book introduces and reviews recent advances inthe field in a comprehensive and non-technical way by focusing on the potentialof emerging citizen-science and social-computation frameworks, coupled with thelatest theoretical and modeling tools developed by physicists, mathematicians,computer and social scientists to analyse, interpret and visualize complex datasets.There is overwhelming evidence that the currentorganisation of our economies and societies is seriously damaging biologicalecosystems and human living conditions in the short term, with potentiallycatastrophic effects in the long term. The need to re-organise the dailyactivities with the greatest impact – energy consumption, transport, housing –towards a more efficient and sustainable development model has recently beenraised in the public debate on several global, environmental issues. Above all,this requires the mismatch between global, societal and individual needs to beaddressed. Recent advancesin Information and Communication Technologies (ICT)can trigger important transitions at the individual and collective level toachieve this aim.Based on the findings of the collaborative researchnetwork EveryAware the following developments among the emerging ICTtechnologies are discussed in depth in this volume:• Participatory sensing – where ICT development ispushed to the level where it can supportinformed action at the hyperlocal scale, providing capabilities forenvironmental monitoring, data aggregation and mining, as well as informationpresentation and sharing.• Web gaming, social computing and internet-mediatedcollaboration – where the Web will continue to acquire the status of aninfrastructure for social computing, allowing users’ cognitive abilities to becoordinated in online communities, and steering the collective action towardspredefined goals.• Collective awareness and decision-making – where theaccess to both personal and community data, collected by users, processed withsuitable analysis tools, and re-presented in an appropriate format by usablecommunication interfaces leads to a bottom-up development of collective socialstrategies.

In the last years, research on Web mining has reached maturity and has broadened in scope. Two different but interrelated research threads have emerged, based on the dual nature of the Web: – The Web is a practically in?nite collection of documents: The acquisition and - ploitation of information from these documents asks for intelligent techniques for information categorization, extraction and search, as well as for adaptivity to the interests and background of the organization or person that looks for information. – The Web is a venue for doing business electronically: It is a venue for interaction, information acquisition and service exploitation used by public authorities, n- governmental organizations, communities of interest and private persons. When observed as a venue for the achievement of business goals, a Web presence should be aligned to the objectives of its owner and the requirements of its users. This raises the demand for understandingWeb usage, combining it with other sources of knowledge inside an organization, and deriving lines of action. ThebirthoftheSemanticWebatthebeginningofthedecadeledtoacoercionofthetwo threadsintwoaspects:(i)theextractionofsemanticsfromtheWebtobuildtheSemantic Web;and(ii)theexploitationofthesesemanticstobettersupportinformationacquisition and to enhance the interaction for business and non-business purposes. Semantic Web mining encompasses both aspects from the viewpoint of knowledge discovery.

Finding knowledge – or meaning – in data is the goal of every knowledge d- covery e?ort. Subsequent goals and questions regarding this knowledge di?er amongknowledgediscovery(KD) projectsandapproaches. Onecentralquestion is whether and to what extent the meaning extracted from the data is expressed in a formal way that allows not only humans but also machines to understand and re-use it, i. e. , whether the semantics are formal semantics. Conversely, the input to KD processes di?ers between KD projects and approaches. One central questioniswhetherthebackgroundknowledge,businessunderstanding,etc. that the analyst employs to improve the results of KD is a set of natural-language statements, a theory in a formal language, or somewhere in between. Also, the data that are being mined can be more or less structured and/or accompanied by formal semantics. These questions must be asked in every KD e?ort. Nowhere may they be more pertinent, however, than in KD from Web data (“Web mining”). Thisis due especially to the vast amounts and heterogeneity of data and ba- ground knowledge available for Web mining (content, link structure, and - age), and to the re-use of background knowledge and KD results over the Web as a global knowledge repository and activity space. In addition, the (Sem- tic) Web can serve as a publishing space for the results of knowledge discovery from other resources, especially if the whole process is underpinned by common ontologies.

The World Wide Web is a rich source of information about human behavior. It containslarge amount of data organizedvia interconnected Web pages,traces of information search, user feedback on items of interest, etc. In addition to large data volumes, one of the important characteristics of the Web is its dynamics, where content,structure and usagearechanging over time. This showsup in the rise of related research areas like communities of practice, knowledge mana- ment, Web communities, and peer-to-peer. In particular the notion of colla- rative work and thus the need of its systematic analysis become more and more important. For instance, to develop e?ective Web applications, it is essential to analyze patterns hidden in the usage of Web resources, their contents and their interconnections. Machine learning and data mining methods have been used extensively to ?nd patterns in usage of the network by exploiting both contents and link structures. We have investigated these topics in a series of workshops on Semantic Web Mining (2001, 2002) at the European Conference on Machine Learning / Pr- ciples and Practice of Knowledge Discovery from Databases (ECML/PKDD) conference series, in the selection of papers for the post-proceedings of the - ropean Web Mining Forum 2003 Workshop, published as the Springer LNAI volume 3209 “Web Mining: From Web to Semantic Web” in 2004, as well as in the Knowledge Discovery and Ontologies workshop in 2004 and in the selection ofpapersfor thepost-proceedingsofthe ECML/PKDD2005jointworkshopson Web Mining (European Web Mining Forum) and on Knowledge Discovery and

This book constitutes the joint thoroughly refereed post-proceedings of The Modeling Social Media Workshop, MSM 2010 held in Toronto, Canada in June 2010 and the International Workshop on Mining Ubiquitous and Social Environments, MUSE 2010, held in Barcelona, Spain in September 2010.The eight revised full papers included were carefully reviewed and selected after two rounds of reviewing and revision. The papers address various aspects of the analysis and engineering of socio-computational systems in which social, ubiquitous and computational processes are interdependent and tightly interwoven

This book constitutes the joint thoroughly refereed post-proceedings of the Second International Workshop on Modeling Social Media, MSM 2011, held in Boston, MA, USA, in October 2011, and the Second International Workshop on Mining Ubiquitous and Social Environments, MUSE 2011, held in Athens, Greece, in September 2011. The 9 full papers included in the book are revised and significantly extended versions of papers submitted to the workshops. They cover a wide range of topics organized in three main themes: communities and networks in ubiquitous social media; mining approaches; and issues of user modeling, privacy and security.

Die neue Generation des Internets („Web 2.0“ oder „Social Web“) zeichnet sich durch eine sehr freizügige Informationsbereitstellung durch seine Nutzer aus. Vor diesem Hintergrund haben Informatiker und Juristen in enger Interaktion die Chancen und Risiken der neuen Web 2.0-Technologien erkundet und gestaltet. Nach Bestandsaufnahme werden die technischen und rechtlichen Chancen und Risiken bezogen auf typisierte Aufgaben analysiert. Generische Konzepte für die datenschutzgerechte Gestaltung einer Anwendung wie Identitätsmanagement, Vermeidung von Personenbezug, Profilbildung und Verantwortlichkeiten werden erarbeitet. Parallel dazu werden Algorithmen und Verfahren für diese Konzepte vorgestellt: Recommender-Systeme für kooperative Verschlagwortungssysteme sowie Spam-Entdeckungsverfahren für solche Systeme. Sie werden anhand realer Daten evaluiert. Alle Ergebnisse werden anhand des Social Bookmarking-Systems BibSonomy erläutert. Schließlich wird diskutiert, inwieweit Dogmatik und Auslegung des Datenschutzrechts wegen der neuen Problemlagen des Web 2.0 verändert werden müssen und eventuell gesetzgeberische Aktivitäten erforderlich oder ratsam sind.