Compureg Plzen (Czechia)

The main challenge in the renewal and updating of the Cadastre of Real Estate of the Czech Republic is to achieve maximum efficiency but to retain the required accuracy of all points in the register. The paper discusses the possibility of using UAV photogrammetry and laser scanning for cadastral mapping in the Czech Republic. Point clouds from images and laser scans together with orthoimages were derived over twelve test areas. Control and check points were measured using geodetic methods (RTK-GNSS and total stations). The accuracy of the detailed survey based on UAV technologies was checked on hundreds of points, mainly building corners and fence foundations. The results show that the required accuracy of 0.14 m was achieved on more than 80% and 98% of points in the case of the image point clouds and orthoimages and the case of the LiDAR point cloud, respectively. Nevertheless, the methods lack completeness of the performed survey that must be supplied by geodetic measurements. The paper also provides a comparison of the costs connected to traditional and UAV-based cadastral mapping, and it addresses the necessary changes in the organisational and technological processes in order to utilise the UAV based technologies.

In this paper, we describe a fair comparison of the performance of a microscopic road traffic simulation performed on a GPU and on a CPU. The aim of our work is to determine the speedup, which can be achieved if the GPU is used for the same simulation instead of the (multi-core) CPU. A microscopic road traffic simulator capable of running on both platforms was created for this purpose with the aim to make the GPU-based and the CPU-based simulations as similar as possible. The performances of both the GPU-based and the CPU-based simulations were tested using two different road traffic models (a car-following model and a cellular automaton model), four road traffic networks (regular square grids of crossroads) of different sizes, and three different hardware configurations. The maximal achieved speedup using the GPU instead of the multi-core CPU for the cellular automaton model was 12.4. For the car-following model, the maximal achieved speedup was 10.7.

The flow in the exhaust hood of a condensing steam turbine depends to a considerable extent on the inlet swirl of the flow which changes in tandem with the volumetric flow of steam through the last stage. This study gives a description of experiments which were carried out on the exhaust hood of a 500 MW steam turbine under various conditions, e.g. when there is rated power, when there is an idle run, or when there are various pressures in the condenser. The flow in a model exhaust hood was investigated by means of CFD methods. Computations were performed with the help of the FLUENT 5 code which is based on solving the Navier-Stokes equations while taking the RSM and LES models of turbulence into consideration. The results of the computations are in full conformity with the experiments.