Although Knowledge Representation is full of reasoning problems that have been formally proved to be both NP-hard and coNP-hard, the experimental analysis has largely focused on problems belonging to either NP or coNP. We still do not know, for example, whether well-studied phenomena such as \phase transition", which show up for many NP-complete problems (e.g., sat) happen for p 2-complete prob...

Osteoarthritis is the most common cause of disability in the developed world. One the most important features of the disease is the progressive thinning and eventual loss of articular cartilage which can be visualised using Magnetic Resonance (MR) imaging. A major goal of research in osteoarthritis is the discovery and development of drugs which preserve the articular cartilage. To guide this r...

Symmetry is one of the most prominent cues in visual perception as well as in computer vision. We have recently presented the Generalized Symmetry Transform that receives as input an edge map, and outputs a symmetry map, where every point mark the intensity and orientation of the local generalized symmetry. In the context of Computer Vision, this map emphasizes points of high symmetry, which, i...

Let Q be a nite set of generalized quantiiers. By L k (Q) we denote the k-variable fragment of FO(Q), rst order logic extended with Q. We show that for each k, there is a PFP(Q)-deenable linear pre-order whose equivalence classes in any nite structure A are the L k (Q)-types in A. For some special classes of generalized quantiiers Q, we show that such an ordering of L k (Q)-types is already dee...

The interaction between intonational marking (focus) and domain restriction in adverbial quantiication has been a matter of debate for a number of years. Most theories assume some semantic representation of focus that innuences the interpretation of quantiiers. Views on this interdependence range from a direct mapping of descriptive content between the two representations to a more indirect int...

Probabilistic expert systems based on Bayesian networks (BNs) require initial speciication of both a qualitative graphical structure and quantitative assessment of conditional probability tables. This paper considers statistical batch learning of the probability tables on the basis of incomplete data and expert knowledge. The EM algorithm with a generalized conjugate gradient acceleration metho...

We present a new method for partial order planning in the STRIPS/SNLP style. Our contribution centers on how we drop the closed world assumption while adding a useful class of universally quantiied propositions to the representation of states and actions. These quan-tiied expressions allow expression of partially closed worlds , such as \block A has no other block on it", or \F is the only Tex ...

This paper aarms that quantiication of life-critical software reliability is infeasible using statistical methods whether applied to standard software or fault-tolerant software. The key assumption of software fault tolerance|separately programmed versions fail independently|is shown to be problematic. This assumption cannot be justiied by experimentation in the ultrareliability region and subj...

We present a theorem-prover for quantiied Boolean formulae and evaluate it on random quantiied formulae and formulae that represent problems from automated planning. Even though the notion of quantiied Boolean formula is theoretically important, automated reasoning with QBF has not been thoroughly investigated. Universal quantiiers are needed in representing many computational problems that can...