Relative periodic orbits in point vortex systems

We give a method to determine relative periodic orbits in point vortex systems: it consists mainly into perform a symplectic reduction on a fixed point submanifold in order to obtain a two-dimensional reduced phase space. The method is applied to point vortices systems on a sphere and on the plane, but works for other surfaces with isotropy (cylinder, ellipsoid, ...). The method permits also to determine some relative equilibria and heteroclinic cycles connecting these relative equilibria.Comment: 27 pages, 17 figure

ISS emergency scenarios and a virtual training simulator for Flight Controllers

The current emergency response concept for the International Space Station (ISS) includes the support of the Flight Control Team. Therefore, the team members need to be trained in emergencies and the corresponding crew procedures to ensure a smooth collaboration between crew and ground. In the case where the astronaut and ground personnel training is not collocated it is a challenging endeavor to ensure and maintain proper knowledge and skills for the Flight Control Team. Therefore, a virtual 3D simulator at the Columbus Control Center (Col-CC) is presented, which is used for ground personnel training in the on-board emergency response. The paper briefly introduces the main ISS emergency scenarios and the corresponding response strategy, details the resulting learning objectives for the Flight Controllers and elaborates on the new simulation method, which will be used in the future. The status of the 3D simulator, first experiences and further plans are discussed

Semiautomatic quality control of topographic reference datasets

The usefulness and acceptance of spatial information systems are mainly dependent on the quality of the underlying geodata. This paper describes a system for semiautomatic quality control of existing geospatial data via automatic image analysis using aerial images, high-resolution satellite imagery (IKONOS and RapidEye) and low-resolution satellite imagery (Disaster Monitoring Constellation, DMC) with mono- and multi-temporal approaches focusing on objects which cover most of the area of the topographic dataset. The goal of the developed system is to reduce the manual efforts to a minimum. We shortly review the system design and then we focus on the automatic components and their integration in a semiautomatic workflow for verification and update. A prototype of the system has been in use for several years. From the experience gained during this time we give a detailed report on the system performance in its application as well as an evaluation of the results