Abstract Transportation businesses reduce costs by optimizing the routes of their trucks. However, determining optimal truck schedules is computationally intensive, running for hours on sequential computers. This article describes experience with parallelizing SAP´s Vehicle Scheduling and Routing Optimizer on shared-memory multicore computers. Re-engineering this complex application for a 24-core machine reduced typical computation time on real data from 1.5 hours to 5 minutes. The article discusses successful and unsuccessful parallelization approaches and concludes with lessons learnt.

Abstract Traditional paper is still widely used in knowledge work due to its specific advantages. The dissertation aims at bridging the gap between paper and digital documents by advancing paper-centric user interfaces. It contributes the first theoretical model of pen-and-paper interfaces, guiding both their analysis and design. Moreover, it contributes novel interaction techniques for annotating, linking, and tagging printed and digital documents. Evaluation studies show that these techniques integrate both types of documents more closely and significantly increase efficiency and user satisfaction.

Abstract Research shows that most social network sites contain serious privacy risks for users. Many of these risks revolve around users´ inability to know exactly who the “audience” is that witnesses their online behaviours. In this article we argue that in the offline world individuals regularly use the strategy of “masking” to hide their visibility when the composition of their audience is unknown. We claim that “masking” should also be facilitated in social network sites to enhance users´ privacy-protection. However, SNSs´ platform design, focused on self-presentation, makes its implementation difficult.

Abstract In craniofacial surgery physicians are often faced with the reconstruction of massively destroyed or radically resected tissue structures caused by trauma or tumors. Also corrections of dislocated bone fragments up to the complete modeling of facial regions in cases of complex congenital malformations are common tasks of plastic and reconstructive surgeons. Such procedures have to be planned and executed thoroughly in order to achieve the best functional as well as an optimal aesthetic rehabilitation. On this account a computer assisted modeling, planning and simulation approach allows for preoperative assessment of different therapeutic strategies on basis of individual, three-dimensional patient models. Bone structures can be mobilized and relocated under consideration of anatomical and functional constraints. The resulting facial appearance can be simulated via finite-element methods on basis of a biomechanical tissue model, and visualized using high quality rendering techniques. Such an approach is not only important for preoperative mental preparation, but also for vivid patient information, documentation, quality assurance as well as for surgical education and training.

Abstract The radio frequency (RF) ablation is a promising minimally invasive form of treatment for hepatic metastases and primary tumors. Thereby a needle like applicator, which is interstitially placed into the lesion, induces an electric current that causes heating and consequent destruction of the tissue due to its Ohmic resistance. In order to be a true alternative to the standard surgical resection, RF ablation must lead to a result similar to R0 resections. Here, patient specific mathematical modeling and numerical simulation of the bio-physical processes lead to a valuable support of the therapy planning, because they allow for an a priori estimation of the success as well as an optimization of the therapy parameters. In this article we discuss a mathematical model of partial differential equations (PDEs) for the patient specific numerical simulation of RF ablation. A particular focus lies on the consideration of uncertainties in the material properties, the underlying image data as well as the computational results. We discuss a stochastic PDE model, which allows for a sensitivity analysis of the computational results with respect to perturbations in the material properties. Furthermore a method for the fast estimation of the thermal necrosis is shown, which bases on the separation of non patient specific pre-calculations and patient specific computations, leading to an interactive real-time simulation tool.

Zusammenfassung Die kontinuierliche Verringerung der Strukturgrößen führt zu einer erhöhten Fehleranfälligkeit von digitalen Schaltungen. Sowohl Produktionsfehler als auch transiente Fehler oder durch Strahlung induzierte Fehler können die Funktionsfähigkeit beeinflussen. Deshalb wird die Untersuchung der Fehlertoleranz im Entwicklungsprozess zunehmend wichtig. In dieser Arbeit wird ein formales Verfahren zur Berechnung der Fehlertoleranz bzgl. kurzzeitig auftretenden Fehlern vorgestellt. Darüber hinaus werden Erweiterungen zur Erhöhung der Genauigkeit, zur Beschleunigung und für die Behandlung von Mehrfachfehlern vorgeschlagen.

Abstract As the field of informatics matures, the range of disciplines that contribute to our understanding of information systems and their use must increase. The International Symposium on Smart Graphics is one of the pioneers of this interdisciplinary scholarship of computation. The highly interactive workshop format includes participants from cognitive and perceptual sciences, art and design, and the humanities as well as the more familiar disciplines of human-computer interaction, artificial intelligence and computer graphics. This paper describes how the new science of visual analytics has built upon the interdisciplinary conversations that events such as Smart Graphics began. This new field of research holds a great deal of promise for a variety of application areas, and serves as an example of how the Smart Graphics approach can support other emerging fields of study.