Refine
Year of publication
- 2004 (5) (remove)
Document Type
Has Fulltext
- no (5)
Is part of the Bibliography
- no (5)
Keywords
Institute
- Fakultät für Informatik (5) (remove)
The strong technical orientation of the previous multimedia evolution shows a lack of theoretical foundation. Both during the evolution and application of multimedia technology, well-founded theoretical concepts are missing. The intention of this paper is to show categories of different information representations and interaction types and their strengths in representing contents. A classification of multimedia information and interaction types is given also as an
overview of the problem fields of multimedia, especially in the field of learning theory. This classification is used to give some guidelines for using and combining multimedia contents in multimedia systems.
OBJECTIVES:
To generate a fast and robust 3-D visualization of the operation site during minimal invasive surgery.
METHODS:
Light fields are used to model and visualize the 3-D operation site during minimal invasive surgery. An endoscope positioning robot provides the position and orientation of the endoscope. The a priori un-known transformation from the endoscope plug to the endoscope tip (hand-eye transformation) can either be determined by a three-step algorithm, which includes measuring the endoscope length by hand or by using an automatic hand-eye calibration algorithm. Both methods are described in this paper and their respective computation times and accuracies are compared.
RESULTS:
Light fields were generated during real operations and in the laboratory. The comparison of the two methods to determine the unknown hand-eye transformation was done in the laboratory. The results which are being presented in this paper are: rendered images from the generated light fields, the calculated extrinsic camera parameters and their accuracies with respect to the applied hand-eye calibration method, and computation times.
CONCLUSION:
Using an endoscope positioning robot and knowing the hand-eye transformation, the fast and robust generation of light fields for minimal invasive surgery is possible.
Java Server Faces
(2004)
Creating long-lived software systems requires a technol ogy to build systems with good maintainability. One of the core ideas of the Model Driven Architecture (MDA) is to ease the change of the run-time platform by raising the level of abstraction in which just the business aspects are modelled, and by separating business aspects from techni cal issues and implementation details. This article anal yses the MDA approach with respect to maintainability. We argue that MDA systems will become even harder to maintain because the maintainability depends on the sys tem's (development) environment. MDA, UML and other base technologies are still under development, therefore the tools will change considerably. While the MDA possibly eases the change of the run-time platform, we show that it is quite difficult to exchange a link in the development tool chain. Our argumentation is based on the general proper ties of software evolution and the dependency chains in the development and run-time environments. It is backed by experiences with MDA development as well as by analo gies to general maintenance experiences.
Dieser Beitrag beschreibt, wie Referenzarchitekturen die MDA nutzbar machen. Die Referenzarchitekturen liefern dabei die konzeptionelle Unterstützung für die Konstruktion und Implementierung von Software und die MDA bietet den Rahmen für eine Werkzeugunterstützung. Die praktische Umsetzbarkeit wird mit dem OpenSource Framework AndroMDA und einer Referenzarchitektur der Firma iteratec GmbH gezeigt.