A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions, and hence have become targets of manipulation by unscrupulous vendors. We provide theoretical and empirical results demonstrating that while common...

A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions and hence have become targets of manipulation by unscrupulous vendors. We demonstrate that nearest neighbors algorithms, which are widely used in...

Resistivity ϱxx and Hall resistivity ϱxy were measured as functions of the magnetic field, temperature, and the metal volume fraction x, on a series of percolating NiSiO2 granular films. At 5 K, the data for the metallic samples were fitted to power law dependencies of the forms, ϱxx ∝...

A large, by a factor of ≈103−104, enhancement of Hall effect in cosputtered magnetic granular metals such as (NiFe)x-(SiO2)1−x near the metal-insulator transition has been termed giant Hall effect (GHE). It is associated with a high resistivity which increases slowly with decreasing...

We studied resistivity, magnetoresistivity and magnetization in granular FeSiO2 films. In the hopping region, magnetoresistance was found to be as large as −5%, and is isotropic for different measurement geometry, which is the signature of giant magnetoresistance due to a spin-dependent...