About
35
Publications
15,985
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
901
Citations
Publications
Publications (35)
Redebeitrag für die 16. Wissenschaftliche Fachtagung der Kriminologischen Gesellschaft in Wien.
Die Kriminologie als empirische, interdisziplinäre Wissenschaft von den Entstehungsbedingungen und Umständen von Kriminalität (vgl. Schmelz 1997: 562) ist eng mit der gesellschaftlichen Entwicklung verbunden. Mit der Digitalisierung der Gesellschaft erg...
Advanced artificial intelligence models are used to solve complex real-world problems across different domains. While bringing along the expertise for their specific domain problems, users from these various application fields often do not readily understand
the underlying artificial intelligence models. The resulting opacity implicates a low level...
Ensembles of classifier models typically deliver superior performance and can outperform single classifier models given a dataset and classification task at hand. However, the gain in performance comes together with the lack of comprehensibility, posing a challenge to understand how each model affects the classification outputs and from where the e...
A fundamental task in criminal intelligence analysis is to analyze the similarity of crime cases, called comparative case analysis (CCA), to identify common crime patterns and to reason about unsolved crimes. Typically, the data are complex and high dimensional and the use of complex analytical processes would be appropriate. State-of-the-art CCA t...
The subject of predictive policing has been very virulent in Germany since 2014. Currently different approaches are running in six federal states. Despite the many approaches, there is still no scientific report that grants a corresponding overview. The reason for the lack of such an overview lies in the fact that less official reports of the diffe...
Five years after the first state-of-the-art report on Commercial Visual Analytics Systems we present a reevaluation of the Big Data Analytics field. We build on the success of the 2012 survey, which was influential even beyond the boundaries of the InfoVis and Visual Analytics (VA) community. While the field has matured significantly since the orig...
Word clouds are a widely-used technique to visualize documents or collections of documents that arranged in a space-efficient 2D layout. Today’s state of the art in 3D computer graphics and its wide availability pose the question, how a 2D word cloud layout can be transferred into 3D space. In this paper, we discuss a prototypical 3D Wordle-based w...
Ensembles of classifier models typically deliver superior performance and can outperform single classifier models given a dataset and classification task at hand. However, the gain in performance comes together with the lack in comprehensibility, posing a challenge to understand how each model affects the classification outputs and where the errors...
Mit diesem Aufsatz sollen die gängigen und häufig anzutreffenden Qualitätsmetriken im Bereich von Predictive-Policing-Umsetzungen dokumentiert, visualisiert und kritisch beleuchtet werden. Neben einer einleitenden Darstellung des methodischen Predictive-Policing-Prozesses werden vor allem die wesentlichen vorhandenen Möglichkeiten zur Trefferratenb...
Named entity recognition (NER) denotes the task to detect entities and their corresponding classes, such as person or location, in unstructured text data. For most applications, state of the art NER software is producing reasonable results. However, as a consequence of the methodological limitations and the well-known pitfalls when analyzing natura...
Diskussionen zu prädiktiven Kriminalitätsanalysen, auch unter dem Begriff Predictive Policing bekannt, prägen aktuell die kriminologische und polizeiwissenschaftliche Literatur. Hersteller entsprechender Softwarelösungen berichten von vielversprechenden Ergebnissen. Medienberichte unterschiedlichster Art setzen sich mit der operativen Umsetzung – m...
Dimensionality reduction (DR) techniques aim to reduce the amount of considered dimensions, yet preserving
as much information as possible. According to many visualization researchers, DR results lack interpretability,
in particular for domain experts not familiar with machine learning or advanced statistics. Thus, interactive
visual methods have b...
Dynamite adopts a multi-level task-driven approach to support event surveillance and time critical decision making for large premises, e.g. casinos or holiday resorts. The system integrates with a complex stream processing engine processing various heterogeneous streams using task-based aggregates. These task stream ensembles are processed in three...
Dynamite adopts a multi-level task-driven approach to support event surveillance and time critical decision making for large premises, e.g. casinos or holiday resorts. The system integrates with a complex stream processing engine processing various heterogeneous streams using task-based aggregates. These task stream ensembles are processed in three...
Visual map features like streets, rail tracks, or rivers do not provide enough space to visualize multiple attributes on them. Related approaches to solve space issues distort the map with lenses, apply distortion techniques to the map geometry, or employ three dimensional visualizations. All these techniques come at the cost of distortion or overl...
Comparative Case Analysis (CCA) is an important tool for criminal investigation and crime theory extraction. It analyzes the commonalities and differences between a collection of crime reports in order to understand crime patterns and identify abnormal cases. A big challenge of CCA is the data processing and exploration. Traditional manual approach...
Colormap design is challenging because the encoding must match the requirements of data and analysis tasks as well as the perception of the target user. A number of well-known tools exist to support the design of colormaps. ColorBrewer [HB03], for example, is a great resource to select colors for qualitative, sequential, and diverging data. PRAVDAC...
To solve the VAST Challenge 2014 MC3 we use NStreamAware, which is our real-time visual analytics system to analyze data streams. We make use of various modern technologies like Apache Spark and others to provide high scalability and incorporate new technologies and show their use within visual analytics applications. Furthermore, we developed a we...
When exploring large spatial datasets, zooming and panning interactions often lead to the loss of contextual overview. Existing overview-plus-detail approaches allow users to view context while inspecting details, but they often suffer from distortion or overplotting. In this paper, we present an off-screen visualization method called Ambient Grids...
Visual analytics enables us to analyze huge information spaces in order to support complex decision making and data exploration. Humans play a central role in generating knowledge from the snippets of evidence emerging from visual data analysis. Although prior research provides frameworks that generalize this process, their scope is often narrowly...
Today, everyone has the possibility to acquire additional information sources as supplement to articles from newspapers or online news. The limitations of classical newspaper articles and restrictions of additional materials on online newsportals often lead to the situation where the reader demands additional news sources and more detailed informat...
Commercial buildings are significant consumers of electrical power. Also, energy expenses are an increasing cost factor. Many companies therefore want to save money and reduce their power usage. Building administrators have to first understand the power consumption behavior, before they can devise strategies to save energy. Second, sudden unexpecte...
Monitoring computer networks often includes gathering vast amounts of time-series data from thousands of computer systems and network devices. Threshold alerting is easy to accomplish with state-of-the-art technologies. However, to find correlations and similar behaviors between the different devices is challenging. We developed a visual analytics...
Large manufacturing companies frequently receive thousands of web surveys every day. People share their thoughts regarding a wide range of products, their features, and the service they received. In addition, more than 190 million tweets (small text Web posts) are generated daily. Both survey feedback and tweets are underutilized as a source for un...
Colorpleth maps are commonly used to display election results, either by using one distinct color for representing the winning party in each district or by showing a proportion between two parties on a bi-polar colormap, for example, from red to blue representing Republicans vs. Democrats. Showing only the largest party may disable insights into th...
The task of the VAST 2011 Grand Challenge was to investigate potential terrorist activities and their relation to the spread of an epidemic. Three different data sets were provided as part of three Mini Challenges (MCs). MC 1 was about analyzing geo-tagged microblogging (Twitter) messages to characterize the spread of an epidemic. MC 2 required ana...