Abstract: A restrictive e-mail system restricts the receiving of junk e-mail by limiting the validity of an e-mail address that can be used at a firewall. An arbitrary e-mail address is allocated for the e-mail directed to each recipient which is unknown to the firewall. A validity stamp is attached to each allocated arbitrary address. The validity stamp can be a recipient's identity, a recipient's e-mail address, an expiration date of the allocated random address, or an accept number of the response e-mails directed to the allocated random address. The firewall checks the validity stamp associated with each incoming e-mail and discards e-mails directed to the arbitrary addresses for which the associated validity stamps are not valid.

Abstract: An electrical alternating current power signal and a circuit and method for generating the same in which the alternating current signal is dropped once at a non-zero crossing point in every 540 plus N degrees, where N is a non-negative number. This manner of controlling power to a device enables wide ranges of power control while generating acceptable levels of power line harmonics and while conforming to existing international regulations governing voltage variations.

Abstract: When a user of a computer seeks a printer having certain capabilities among a large population of printers dispersed over a large geographical area, the user consults a substantially open database of geographical data about each of the population of printers. Relational data is used with the geographical data to determine an effective distance of each suitable printer to a predetermined location. The effective distance determination can take into account distances within a building, or among different buildings.