Vision-based human action and activity recognition has an increasing importance among the computer vision community with applications to visual surveillance, video retrieval and human-computer interaction. In recent years, more and more datasets dedicated to human action and activity recognition have been created. The use of these datasets allows us to compare different recognition systems with the same input data. The survey introduced in this paper tries to cover the lack of a complete description of the most important public datasets for video-based human activity and action recognition and to guide researchers in the election of the most suitable dataset for benchmarking their algorithms.

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Although a meanline code solves simple algebraic equations, some difficulties arise in flows near choked condition. Using simplified 0-dimensional (0D) models, it is shown which flow variable drives this phenomena (total or meridional Mach number) depending on the boundary conditions. It is commented as well how the choked condition is modified depending on the loss coefficient used. Then, a novel numerical method based on a bisection approach is proposed to solve meanline equations. A simple method to enlarge speed lines obtained by the mean-line solver is also described. Finally, the performance map of a single-stage axial compressor is computed and compared with experimental data to show the capabilities of the proposed approach.

A new, fast and reliable loosely coupled fluid-solid heat transfer method is described. The approach is based on an improvement of heat transfer coefficient Forward Temperature Backward method. The numerical analysis of the coupling process of an one-dimensional model, shows that the convergence behaviour is influenced by the physical Biot number and a virtual heat transfer coefficient. The effect of using partially converged CFD solutions has also been studied. The novelty of the method is based on the use of dynamic evaluation of the numerical parameters of the coupling, namely the virtual heat transfer coefficient. Two representative models in turbomachinery applications are applied to test the proposed method. It is shown that the computational time can be reduced by a factor of three to five relative to previous existing methods. The new approach only spends around two times the cost of stand-alone CFD simulation of the problem to obtained a coupled fluid/solid thermal analysis.

A transient aero-thermal analysis of the disk cavities of an aero-engine LPT (Low Pressure Turbine) is presented. The full simulation includes a 2D thermal model of the solid parts combined with an axisymmetric flow model of six separate cavities interconnected through inlet and outlet boundaries. Computing elapsed time is significantly reduced by using a cluster of GPUs (Graphics Processing Units) making this approach compatible with turbine design time-frames. The problem of flow reversal that takes place in some of the cavity boundaries along the transient flight cycle is addressed in detail. The fully coupled numerical solution is validated against engine data and compared as well against an uncoupled simulation. It is shown that the coupled solution outperforms the uncoupled one in terms of accuracy, since it removes some hypotheses inherent to the uncoupled approach. It is believed that this is the first time that GPUs have been used to solve a fully coupled fluid/solid thermal problem of industrial interest for the gas turbine community.