Semiotics is considered fundamental to an understanding of human±computer interaction, and of all computer artifacts. Informatics should therefore be viewed as technical semiotics (or semiotics engineering). In particular, interaction between human and computer is characterized by features of communication, a sort of communication, however, that lacks decisive communicative features. It must be...

In this paper, we add a module system to supernormal default speciications (which have a circumscription-like \minimal model" semantics). Our intention is to formalize that certain rules deene certain elementary facts; we do not consider the more syntactical side of modules (such as the hiding of names). Logic programs can be naturally translated into this system by taking the head literal as t...

A l l i s C h a l m e r s M a n u f a c t u r i n g C o M a r a t h o n Oi l C o . * N a t i o n a l B a n k o f D e t r o i t . D o w C h e m i c a l C o . T H U R S . N O V . 1 9 A m e r i c a n C y a n a m i d C o . C o n t i n e n t a l I l l i no i s N a t i o n a l B a n k a n d T r u s t C o m p a n y o f C h i c a g o . C o r n i n g G l a s s Wo r ks . E s s e x I n t e r n a t i o n a...

We study here a natural situation when constraint programming can be entirely reduced to rule-based programming. To this end we explain first how one can compute on constraint satisfaction problems using rules represented by simple first-order formulas. Then we consider constraint satisfaction problems that are based on predefined, explicitly given constraints. To solve them we first derive rul...

Barrels are patterned groups of neurons in rodent somatosensory cortex that correspond one to one with the animal's facial whiskers. Dirichlet domains are a class of convex polygon found frequently in nature, often arising by nucleation from center points. Analytic and graphical methods were devised to verify the hypothesis that Dirichlet domains accurately describe the adult barrel fields of n...

The WSR-57 radar a t Sacramento provides an opportunity to observe mountain effects on precipitation and on radar echo patterns. Radar patterns representing a wide range of weather situations are described and interpreted in light of concurrent gage precipitation measurements. The frequent underestimation by radar of rainfall on windward slopes is attributed to the small drop size and low forma...

In this paper we present a calculus of temporal operators that is intended as an alternative to temporal logic in program verification. Temporal logic is a form of modal logic, designed for the description of time-dependent phenomena. Several different kinds of temporal logic have been proposed, but in the present paper only the linear time version [13] is treated. A common characteristic of al...

The modern study of perception began when Fechner published his 'Elements of Psychophysics' in 1860. This book has guided most perception research ever since. It has become increasingly clear that there are problems with Fechner's approach, which assumes that the percept is completely determined by the sensory input. Fechner's approach cannot explain the processes that allow our percepts to be ...