Here we describe an approach, based upon a notion of problem similarity, that can be used when attempting to devise a heuristic for a given search problem (of a sort represented by graphs). The proposed approach relies on a change in perspective: instead of seeking a heuristic directly for a given problem PI, one seeks instead a rolp___21gm P2 easier to solve than PI and related to PI in a cert...

A problem with A* is that it fails to guarantee opt imal solutions when its heuristic, h, overestimates. Since optimal solutions are often desired and an underestimating h is not always available, we seek to remedy this. From a nonadmissible h an admissible one is generated using h's statistical properties. The new heuristic, hm, is obtained by inverting h wi th respect to its own least upper b...

In rea l -wor ld domains a concept to be learned may be unwieldy and the environment may be less than ideal. One combinat ion of difficulties occurs if the concept is probabi l ist ic and the learning si tuat ion is dynamic. In this case, the data may be noisy and biased. These difficulties arise when learning evaluation functions, which can be considered as concepts. A representative problem, ...

Client puzzles are meant to act as a defense against denial of service (DoS) attacks by requiring a client to solve some moderately hard problem before being granted access to a resource. However, recent client puzzle difficulty definitions (Stebila and Ustaoglu, 2009; Chen et al., 2009) do not ensure that solving n puzzles is n times harder than solving one puzzle. Motivated by examples of puz...

Technological breakthroughs in physics are often adapted and incorporated into the ever growing field of otolaryngology. When first discovered, “The Incredible Laser” had promised to be science’s new “Aladdin’s lamp”, it can “light up the moon”, “kill instantly”, or “perform miracle surgery” [1]. Although not quite fulfilling these roles, laser technology has been a key element in the developme...

In situations where one needs to make a sequence of decisions, it is often believed that looking ahead will help produce better decisions. However, it was shown 30 years ago that there are “pathological” situations in which looking ahead is counterproductive. Two long-standing open questions are (a) what combinations of factors have the biggest influence on whether lookahead pathology occurs, a...