Digital systems offer computational power and instant feedback. Game designers are using these features to create scaffolding tools to reduce player frustration. However, researchers are finding some unexpected effects of scaffolding on strategy development and problem-solving behaviors. We used a digital Sudoku game named Professor Sudoku to classify built-in critical features, frustration con...

| Lagrangian stochastic models and algorithms are constructed and justi ed for solving the footprint problem, namely, the problem of calculation of the mean concentration and the ux of particles at a xed point released from a source arbitrarily situated in the space. The direct and adjoint Monte Carlo algorithms are suggested, and rigorous justi cations are given. Two di erent backward trajecto...

Reconstructing neuronal activity from MEG and EEG measurements requires the accurate calculation of the electromagnetic field inside the head. The boundary element formulation of this problem leads to a dense linear system which is too large to be solved directly. We propose to accelerate the computations via the fast multipole method. This method approximates the electromagnetic interaction be...

In this paper we present the problem of designing a three level hub center network. In our network, the top level consists of a complete network where a direct link is between all central hubs.  The second and third levels consist of star networks that connect the hubs to central hubs and the demand nodes to hubs and thus to central hubs, respectively. We model this problem in an incomplete net...