Abstract: The invention uses pair-wise relations such as dissimilarity, similarity or correlation to identify related items by translating the relations into a set of points in a geometric space, where each point in the set of points represents an item, and where the distance between any two points directly corresponds to the dissimilarity value of the two items represented by the two points. A family of graphs is computed from the Voronoï diagram for the set of points. This family of graphs may be used for a variety of applications, including recommendation systems. For some applications, clustering may be used to assist in visualizing and identifying relations among items. In the case of recommendation systems, graphs reflecting customer preferences are clustered to identify customers with similar tastes.

Abstract: We describe systems and methods that allow absolute security of the stability of screwing by screws when access to said screw is possible neither from the side nor from beneath. Said stability is achieved in a reversible way in the sense that unscrewing can easily be performed without breaking when needed. A variety of systems and methods are disclosed with these attribute, which can in particular apply to the trans-screwing of a prosthetic abutment on the crestal end of a dental implant, with many more applications.

Abstract: Dice are disclosed that detect their state, i.e., their own value once at rest, using for instance gravity, piezoelectricity, or photoelectric cells that are assigned to all faces to recognize the lower face. Said dice preferably transmit said state to a computer. Said computer may be the same that is used for the game that depends on the throw of the dice, or may be used mostly for display as for some casino games. Electricity is used in the die to let it determine its own state and transmit it. Economical protocols of transmission are used such as Bluetooth. Such dice may securely send alerts whenever deviations from a fair distribution of the outcomes is detected and can monitor small modifications of their balance to maintain their fairness. Part or all of the teaching can be realized as MEMS (micro electro-mechanical systems) or NEMS (nano electromechanical systems) modifications of usual dice.