Dauerbelichtung

Zwischen 2002 und 2004 hat Christoph Klute in Frankreich und Deutschland sämtliche Unités d'habitation des Architekten Le Corbusier fotografiert. Was in den 50er und 60er Jahren als eine architektonische Verheißung erschien, wirkt heute anders. Die Bilder fangen den genius loci der Orte behutsam ein, ohne Spuren des Alters oder des Gebrauchs oder zu ignorieren.

Topologically Accurate Dual Isosurfacing Using Ray Intersection

“Dual contouring” approaches provide an alternative to standard Marching Cubes (MC) method to extract and approximate an isosurface from trivariate data given on a volumetric mesh. These dual approaches solve some of the problems encountered by the MC methods. We present a simple method based on the MC method and the ray intersection technique to compute isosurface points in the cell interior. One of the advantages of our method is that it does not require us to use Hermite interpolation scheme, unlike other dual contouring methods. We perform a complete analysis of all possible configurations to generate a look-up table for all configurations. We use the look-up table to optimize the ray-intersection method to obtain minimum number of points necessarily sufficient for defining topologically correct isosurfaces in all possible configurations. Isosurface points are connected using a simple strategy.

Durch die Gänge der Fabriken läuft der Stundenzähler

Der Lehrstuhl für Transportsysteme und -logistik der Universität Duisburg-Essen befasst sich derzeit mit einem Forschungsprojekt in der Intralogistik. Es handelt sich dabei um das Themengebiet „Einsatz von Flurförderzeugen“. Ziel der Untersuchung ist es, die Ermittlung der Einsatzzeit der Fahrzeuge systematisch zu erfassen und darzustellen. Die Messung der Einsatzzeit hat eine große Bedeutung, wenn es um die Berechnung der Nutzungsdauer und damit um die Kostenabrechnung bei bestimmten Miet-, Leasing oder auch Wartungsverträgen geht. Darüber hinaus dient die Einsatzzeit auch als Berechnungsgrundlage zur Dimensionierung von Fahrzeugflotten zur Bewältigung logistischer Transportaufgaben. Die Ermittlung der Einsatzzeit der Flurförderzeuge erfolgt auf verschiedene Art und Weise – je nach Hersteller oder Vertragsform. Dieses Dokument erläutert die Ergebnisse von einem Fragebogen zur Messung der Einsatzzeit. Für die weitere Informationen und die Präsentation von den Ergebnissen, besuchen Sie bitte folgende Webseite http://www.uni-duisburg-essen.de/tul/

Logfile-Analysen zur Evaluation der didaktischen Einbettung von CSCL-Systemen

In unserem Beitrag evaluieren wir die didaktische Einbettung einer CSCL-Anwendung anhand von Logfile-Analysen. Dazu betrachten wir exemplarisch die Nutzung des webbasierten Systems CommSy in einer projektorientierten Lehrveranstaltung, die wir als offenes Seminar charakterisieren. Wir erzielen zwei Ergebnisse: (1) Wir geben Hinweise zur Gestaltung des Nutzungskontexts eines CSCL-Systems sowie zur Unterstützung seiner anfänglichen und kontinuierlichen Nutzung. (2) Wir beschreiben die Analyse von Nutzungsanlässen und -mustern sowie von NutzerInnentypen anhand von Logfiles. Dabei können Logfile-Analysen zur Validierung weiterer Evaluationsergebnisse dienen, sind selbst jedoch nur in Kombination mit zusätzlichen Informationen zum Nutzungskontext interpretierbar.

Matching Software and Context in Open Learning Scenarios

We describe the use of log file analysis to investigate whether the use of CSCL applications corresponds to its didactical purposes. Exemplarily we examine the use of the web-based system CommSy as software support for project-oriented university courses. We present two findings: (1) We suggest measures to shape the context of CSCL applications and support their initial and continuous use. (2) We show how log files can be used to analyze how, when and by whom a CSCL system is used and thus help to validate further empirical findings. However, log file analyses can only be interpreted reasonably when additional data concerning the context of use is available.

Rollout of CampusContent

CampusContent (CC) is a DFG-funded competence center for eLearning with its own portal. It links content and people who support sharing and reuse of high quality learning materials and codified pedagogical know-how, such as learning objectives, pedagogical scenarios, recommended learning activities, and learning paths. The heart of the portal is a distributed repository whose contents are linked to various other CampusContent portals. Integrated into each portal are user-friendly tools for designing reusable learning content, exercises, and templates for learning units and courses. Specialized authoring tools permit the configuration, adaption, and automatic generation of interactive Flash animations using Adobe's Flexbuilder technology. More coarse-grained content components such as complete learning units and entire courses, in which contents and materials taken from the repository are embedded, can be created with XML-based authoring tools. Open service interface allow the deep or shallow integration of the portal provider's preferred authoring and learning tools. The portal is built on top of the Enterprise Content Management System Alfresco, which comes with social networking functionality that has been adapted to accommmodate collaboration, sharing and reuse within trusted communities of practice.

Tariff-Specific Preferences and Their Influence on Price Sensitivity

For many services, consumers can choose among a range of optional tariffs that differ in their access and usage prices. Recent studies indicate that tariff-specific preferences may lead consumers to choose a tariff that does not minimize their expected billing rate. This study analyzes how tariff-specific preferences influence the responsiveness of consumers’ usage and tariff choice to changes in price. We show that consumer heterogeneity in tariff-specific preferences leads to heterogeneity in their sensitivity to price changes. Specifically, consumers with tariff-specific preferences are less sensitive to price increases of their preferred tariff than other consumers. Our results provide an additional reason why firms should offer multiple tariffs rather than a uniform nonlinear pricing plan to extract maximum consumer surplus.

GPU-based Ray Tracing of Dynamic Scenes

Interactive ray tracing of non-trivial scenes is just becoming feasible on single graphics processing units (GPU). Recent work in this area focuses on building effective acceleration structures, which work well under the constraints of current GPUs. Most approaches are targeted at static scenes and only allow navigation in the virtual scene. So far support for dynamic scenes has not been considered for GPU implementations. We have developed a GPU-based ray tracing system for dynamic scenes consisting of a set of individual objects. Each object may independently move around, but its geometry and topology are static.

Liability for Copyright Infringements on the Internet: Host Providers (Content Providers) - The Geman Approach

Copyright infringements on the Internet affect all types of media which can be used online: films, computer games, audio books, music, software, etc. For example, according to German studies, 90% of all copyright violations affecting film works take place on the Internet. This storage space is made available to such infringers, as well as to others whose intentions are legal, by hosting providers. To what extent do hosting providers have a duty of care for their contribution to the copyright infringements of third parties, i.e. their users? What duties of care can be reasonably expected of hosting providers to prevent such infringements? These questions have been heavily debated in Germany, and German courts have developed extensive case law. This article seeks to examine these questions by assessing German jurisprudence against its EU law background.

Distributed Repositories for Educational Content

As education providers increasingly integrate digital learning media into their education processes, the need for the systematic management of learning materials and learning arrangements becomes clearer. Digital repositories, often called Learning Object Repositories (LOR), promise to provide an answer to this challenge. This article is composed of two parts. In this part, we derive technological and pedagogical requirements for LORs from a concretization of information quality criteria for e-learning technology. We review the evolution of learning object repositories and discuss their core features in the context of pedagogical requirements, information quality demands, and e-learning technology standards. We conclude with an outlook in Part 2, which presents concrete technical solutions, in particular networked repository architectures.

Distributed Repositories for Educational Content

In Part 1 of this article we discussed the need for information quality and the systematic management of learning materials and learning arrangements. Digital repositories, often called Learning Object Repositories (LOR), were introduced as a promising answer to this challenge. We also derived technological and pedagogical requirements for LORs from a concretization of information quality criteria for e-learning technology. This second part presents technical solutions that particularly address the demands of open education movements, which aspire to a global reuse and sharing culture. From this viewpoint, we develop core requirements for scalable network architectures for educational content management. We then present edu-sharing, an advanced example of a network of homogeneous repositories for learning resources, and discuss related technology. We conclude with an outlook in terms of emerging developments towards open and networked system architectures in e-learning.