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Web-based learning environments such as the Go-Lab portal facilitate the structuring and scaffolding of inquiry processes and enable learners to create various types of knowledge artefacts (texts, concept maps, hypotheses). In this context, we have introduced semantic technologies to extract key concepts from heterogeneous learner-generated artefacts. Based on this approach, we propose an algorithm...
To conduct scientific experiments is a central aspect in science education in secondary schools. Online laboratories overcome a variety of deficits and obstacles that complicate in situ experiments, particularly regarding accessibility, availability, financial costs and preparation time. However, such a computer-supported learning approach still demands for motivating and playful scenarios to catch...
In this paper three similarity measures for scientific papers are compared: bibliographic coupling, co-citation coupling and cosine similarity. All three measures are based on the connections of papers in citation networks. The comparison is conducted both on a mathematical as well as an empirical level. The latter is performed on a real citation network as well as artificially generated networks...
Explicit visual representations of domain knowledge have the potential to support students engaged in scientific inquiry learning activities on an epistemic level. This can be facilitated using computational methods for the extraction of concepts from student generated knowledge artefacts such as hypotheses, concept maps, or wiki articles. We propose an application of this approach in the context...
Detection of influential actors in social media plays an important role for increasing the quality and efficiency of work and services in many fields such as education, marketing, etc. Thiswork aims to introduce a new approach for the characterization of influential actors in online social media, such as Twitter. We present on a model of influence of an actor that is based on the attractiveness of...
In this paper, we present a set of algorithms to compute a foresighted graph layout. We aim to produce a dynamic graph drawing that allows the users to track actors in a dynamic social network, supporting a satisfying user experience along with an efficient visual search and recognition of elements. The drawings produced by the algorithms were evaluated through a study, which combined the use of questionnaires,...
This work explores network analysis methods for the analysis of emergent themes as well as types of users in discussion forums. The paper provides both, a description of the analysis approach and its application as a case study. To that end, keywords are extracted from forum threads and then linked to the forum users resulting in a bipartite network based on their activity in discussion threads. Applying...
This work explores methods to investigate the structure of knowledge exchange in discussion forums in massive open online courses (MOOCs) explicitly taking into account changing patterns over time. Various aspects of forum analysis combining different approaches are exemplified with a case of forum discussions from a Coursera MOOC.
In this demo paper we present a new visualization technique for dynamic networks. It displays the time slices of the dynamic network using two dimensional graph layouting algorithms and stacks these in the third dimension to show the development over time. The visualization ensures that the same node always has the same position in each time slice so that it is easy to follow its development. It also...
In this paper, we propose a mathematical model to measure the visual stability of dynamic graph drawings. Our approach was validated through a study, which combined the use of questionnaires and an eye-tracking device. The participants of the study had to track members of a software development community over five periods of time in three different dynamic graph drawings. The results suggest that...
In this paper we introduce a method and implementation to detect and classify specific episodes of scientific collaboration. Our method uses co-authorship networks and creates indicators for the discovery of temporal patterns of co-authoring. We apply the concept and implementation to scientific communities of the fields collaborative systems and social network analysis, to compare our findings to...
This paper deals with the problem of identifying clusters in evolving bipartite networks over time. In bipartite networks there exist two types of nodes while ties can only occur between nodes of different types. Hence, a cluster in a bipartite network consists of two node sets for the two node types each. A major challenge regarding the evolution of those clusters over time is that the two parts...
In this paper we introduce the concept of a web-based analytics workbench to support researchers of social networks in their analytic processes. Making explicit these processes allows for sound design, re-use, and automated execution using an authoring system for visual representations of these analytic workflows. The workbench is implemented according to a flexible technical framework in which external...
This paper introduces an agglomerative method for detecting cohesive subgroups in networks based on geodesic distance. The algorithm starts with a set of nodes as "seed". Beginning with the seed nodes as initial clusters, the clusters grow by incorporating more nodes successively based on minimal average distance to the current members of the cluster as a criterion for cluster extension...
Free-hand drawing of diagrams or sketches is a natural form of expression in a variety of learning settings. It is easily supported by tablets or tablet PCs. Often such sketches are the basis of reasoning processes, also in collaborative scenarios. Sketches can indicate misconceptions. Therefore it is desirable to support a semantic interpretation of sketches integrated with other parts of a learning...
In recent years the diversity and the ownership of mobile devices steadily increased while the prices for this kind of devices decreased to a level that allows many students to own reasonably powerful devices. As mobile devices are also being used in learning scenarios, the challenge of today is the integration of multiple heterogeneous devices into existing and upcoming learning scenarios. This paper...
Today's mobile learning application development does not only require a sophisticated pedagogical design, but also faces a number of technical challenges to overcome several problems and limitations. In this paper, we present common challenges in scaling mobile learning applications for real world environments and exemplify our solutions and decisions for the collaborative and context-aware quiz playing...
Self-directed learning with learning management systems can be intelligently supported and enriched using available log data in combination with detailed competence ontologies. The approach described here implements a mechanism to adaptively generate quizzes for self-assessment in a Moodle environment. The underlying agent architecture uses a tuple space in the role of a blackboard. The approach has...
Most of the existing mobile learning environments for supporting field trip activities are limited to specific domains or contents and do not support authoring. We present a framework for planning and conducting field trips with mobile devices called LEMONADE, which provides full cycle support for authoring and conducting field trips, as well as for post-trip reporting and reflection activities. LEMONADE...
Representational flexibility can be seen as one of the essential advantages of pen based input over conventional computer tools, especially for creative and problem solving tasks. We have tried to demonstrate this benefit in the area of Sudoku solving. However, it turned out that the supposedly obvious affordances of the pen based environment were not really exploited in our exploratory studies. This...
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