This paper describes research eeorts to develop eecient implementation techniques for disjunctive deductive databases. The aim is to build a database engine that produces perfect model semantics as introduced by Przymusinski. When used with positive dis-junctive databases the results would be equivalent to that of minimal model semantics. Our strategy is to build Access Clause Trees (ACTs) base...

Starting from a complete graph on n vertices, repeatedly delete the edges of a uniformly chosen triangle. This stochastic process terminates once it arrives at a triangle-free graph, and the fundamental question is to estimate the final number of edges (equivalently, the time it takes the process to finish, or how many edge-disjoint triangles are packed via the random greedy algorithm). Bollobá...

Steganography is the science of hiding a message signal in a host signal, without any perceptual distortion of the host signal. Using steganography, information can be hidden in the carrier items such as images, videos, sounds files, text files, while performing data transmission. In image steganography field, it is a major concern of the researchers how to improve the capacity of hidden data i...

background: tinea pedis is probably the commonest form of dermatophy10ses in developed countries and is one of the public heath problems. the wearing of shoes and resultant maceration of toe cleft predisposes to this condition. the aim of this survey was study of conditions and prevalence or tinea pedis in health stave of hamadan, sina hospital. methods: a quality descriptive cross sectional st...