Hasso Plattner Institute Potsdam

Potsdam, Germany

Hasso Plattner Institute Potsdam

Potsdam, Germany

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Trumper J.,Hasso Plattner Institute Potsdam | Telea A.,University of Groningen | Dollner J.,Hasso Plattner Institute Potsdam
Theory and Practice of Computer Graphics 2012, TPCG 2012 - Eurographics UK Chapter Proceedings | Year: 2012

Visualization of data on structure and related temporal activity supports the analysis of correlations between the two types of data. This is typically done by linked views. This has shortcomings with respect to efficient space usage and makes mapping the effect of user input into one view into the other view difficult. We propose here a novel, space-efficient technique that 'fuses' the two information spaces - structure and activity - in one view. We base our technique on the idea that user interaction should be simple, yet easy to understand and follow. We apply our technique, implemented in a prototype tool, for the understanding of software engineering datasets, namely static structure and execution traces of the Chromium web browser. © The Eurographics Association 2012.


Thalhammer A.,University of Innsbruck | Knuth M.,Hasso Plattner Institute Potsdam | Sack H.,Hasso Plattner Institute Potsdam
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In recent years, strategies for Linked Data consumption have caught attention in Semantic Web research. For direct consumption by users, Linked Data mashups, interfaces, and visualizations have become a popular research area. Many approaches in this field aim to make Linked Data interaction more user friendly to improve its accessibility for non-technical users. A subtask for Linked Data interfaces is to present entities and their properties in a concise form. In general, these summaries take individual attributes and sometimes user contexts and preferences into account. But the objective evaluation of the quality of such summaries is an expensive task. In this paper we introduce a game-based approach aiming to establish a ground truth for the evaluation of entity summarization. We exemplify the applicability of the approach by evaluating two recent summarization approaches. © 2012 Springer-Verlag Berlin Heidelberg.


Waitelonis J.,Hasso Plattner Institute Potsdam | Sack H.,Hasso Plattner Institute Potsdam
Multimedia Tools and Applications | Year: 2012

Keyword-based search in general is particularly applicable if the searcher really knows what she is looking for and how to find it, i.e. to know the appropriate keywords to obtain the desired results. But in many cases either the objectives of the searcher are intrinsically fuzzy or she is not aware of the appropriate keywords. One way to solve this problem is to navigate and explore the search space along guided routes. In this paper we show, how Linked Open Data can be adopted to facilitate an exploratory semantic search for video data. We present a prototype implementation of exploratory video search and show how traditional keyword-based search can be augmented by the use of Linked Open Data. © Springer Science+Business Media, LLC 2011.


Wenzel M.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
2015 International Conference on Collaboration Technologies and Systems, CTS 2015 | Year: 2015

In modern computer systems, multicore processors are prevalent, even on mobile devices. Since JavaScript WebWorkers provide execution parallelism in a web browser, they can help utilize multicore CPUs more effectively. However, WebWorker limitations include a lack of access to web browser's native XML processing capabilities and related Document Object Model (DOM). We present a JavaScript DOM and XML processing implementation that adds missing APIs to WebWorkers. This way, it is possible to use JavaScript code that relies on native APIs within WebWorkers. We show and evaluate the seamless integration of an external XMPP library to enable parallel network data and user input processing in a web based real-time remote collaboration system. Evaluation shows that our XML processing solution has the same linear execution time complexity as its native API counterparts. The proposed JavaScript solution is a general approach to enable parallel XML data processing within web browser-based applications. By implementing standards compliant DOM interfaces, our implementation is useful for existing libraries and applications to leverage the processing power of multicore systems. © 2015 IEEE.


Wenzel M.,Hasso Plattner Institute Potsdam | Gericke L.,Hasso Plattner Institute Potsdam | Gumienny R.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
Proceedings of the 2013 IEEE 17th International Conference on Computer Supported Cooperative Work in Design, CSCWD 2013 | Year: 2013

Mobile devices such as smartphones and tablets play an increasing role in today's working environment. The variety of computer platforms increased in the same way, which makes the development of cross-platform applications even more challenging. Tele-Board is a real-time remote collaboration system based on the Java programming language. Therefore, it cannot be run on most mobile devices. In order to overcome this limitation, we redeveloped the system on the basis of HTML5 technology. We present an approach for combining web based networking and rendering in a single application for real-time collaboration based on SVG, HTML5 Canvas, Websockets, and Web workers. In our prototype we implemented optimization mechanisms leveraging the Canvas API's rendering flexibility. This way, our canvas based rendering performs better than a respective SVG version. Moreover, our solution integrates server communication effectively so that the rendering performance is hardly influenced by user input. © 2013 IEEE.


Gericke L.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
Proceedings of the 2013 International Conference on Collaboration Technologies and Systems, CTS 2013 | Year: 2013

In this paper, we present a concept for developing applications that allow users to work synchronously together while being able to use asynchronous features, such as work resumption from any point in time. Therefore, we formulate abstract requirements for a protocol realizing the introduced approach. Furthermore, an architecture for deployment is outlined. We show three different applications - all realizing the proposed method. An evaluation summarizes the drawbacks and advantages of the approach. The introduced concept should show up a practical solution especially to sufficiently store collaboration processes. By proving the combination of synchronous and asynchronous features into one application to fulfill basic user needs, it could be an efficient way for applications realizing two working modes, which mostly have been addressed separately in previous solutions. © 2013 IEEE.


Hewelt M.,Hasso Plattner Institute Potsdam | Weske M.,Hasso Plattner Institute Potsdam
Lecture Notes in Business Information Processing | Year: 2016

While the business process management community has concentrated on modelling and executing business processes with a known structure, support for processes with a high degree of variability performed by knowledge workers is still not satisfactory. A promising approach to overcome this deficiency is case management. Despite of the work done in the area of case management in recent years, there is no accepted case handling formalism that features a well defined semantics. This paper introduces a novel approach to case management, which is based on dynamically combining process fragments as required by knowledge workers. An operational semantics defines the meaning of case models in detail, using states of data objects and enablement conditions of process fragments. © Springer International Publishing Switzerland 2016.


Wenzel M.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
Proceedings of the 2016 IEEE 20th International Conference on Computer Supported Cooperative Work in Design, CSCWD 2016 | Year: 2016

Remote collaboration systems are a necessity for geographically dispersed teams in achieving a common goal. Real-time groupware systems frequently provide a shared workspace where users interact with shared artifacts. However, a shared workspace is often not enough for maintaining the awareness of other users. Video conferencing can create a visual context simplifying the user's communication and understanding. In addition, flexible working modes and modern communication systems allow users to work at any time at any location. It is therefore desirable that a groupware system can run on users' everyday devices, such as smartphones and tablets, in the same way as on traditional desktop hardware. We present a standards compliant, web browser-based real-time remote collaboration system that includes WebRTC-based video conferencing. It allows a full-body video setup where everyone can see what other participants are doing and where they are pointing in the shared workspace. In contrast to standard WebRTC's peer-to-peer architecture, our system implements a star topology WebRTC video conferencing. In this way, our solution improves network bandwidth efficiency from a linear to a constant network upstream consumption. © 2016 IEEE.


Gumienny R.,Hasso Plattner Institute Potsdam | Gericke L.,Hasso Plattner Institute Potsdam | Quasthoff M.,Hasso Plattner Institute Potsdam | Willems C.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
Proceedings of the 2011 15th International Conference on Computer Supported Cooperative Work in Design, CSCWD 2011 | Year: 2011

Remote collaboration among geographically dispersed team members has become standard practice for many companies and research teams. A number of computer supported collaborative work systems exist, but there still lacks acceptable support for teams working in creative settings, where traditionally numerous physical and analog tools are used. We have created an environment for teams applying creative methods that allows them to work together efficiently across distances, without having to change their working modes. We present the Tele-Board system, which combines video conferencing with a synchronous transparent whiteboard overlay. This setup enables regionally separated team members to simultaneously manipulate artifacts while seeing each other's gestures and facial expressions. Our system's flexible architecture maximizes hardware independence by supporting a diverse selection of input devices. © 2011 IEEE.


Gericke L.,Hasso Plattner Institute Potsdam | Gumienny R.,Hasso Plattner Institute Potsdam | Meinel C.,Hasso Plattner Institute Potsdam
ColiaborateCom 2011 - Proceedings of the 7th International Conference on Collaborative Computing: Networking, Applications and Worksharing | Year: 2011

We present the digital whiteboard system Tele-Board, which automatically captures all interactions made on the all-digital whiteboard and thus offers possibilities for a fast interpretation of usage characteristics. Analyzing team work at whiteboards is a time-consuming and error-prone process if manual interpretation techniques are applied. In a case study, we demonstrate how to conduct and analyze whiteboard experiments with the help of our system. The study investigates the role of video compared to an audio-only connection for distributed work settings. With the simplified analysis of communication data, we can prove that the video teams were more active than the audio teams and the distribution of whiteboard interaction between team members was more balanced. In this way, automatic analyses can not only support manual observations and codings, but also give insights that cannot be achieved with other systems. © 2011 ICST.

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