The basic ideas underlying the Kalman filter are outlined in this paper without direct recourse to the complex formulae normally associated with this method. The novel feature of the paper is its reliance on a new algebraic system based on the first two moments of the multivariate normal distribution. The resulting framework lends itself to an object-oriented implementation on computing machine...

Radio Doppler data from the Cassini spacecraft during its solar conjunction in June 2002 can be used to test General Relativity. In terms of the standard post-Newtonian parameter 7 , the result is y 1 = (-4.8 f 5.7) x including both random and systematic error. Einstein’s theory has survived yet another test.

Einstein's relation between the mass of a body and the energy contained in it is undoubtedly the most famous formula of the theory of relativity. It permitted a new and deeper understanding of the world that surrounds us. Its practical consequences are vast and, to a large degree, tragic. In a certain sense this formula has become the symbol of science in the 20th century. What is the need for ...

Product systems are the classifying structures for semigroups of endomorphisms of B(H), in that two E0-semigroups are cocycle conjugate iff their product systems are isomorphic. Thus it is important to know that every abstract product system is associated with an E0-semigrouop. This was first proved more than fifteen years ago by rather indirect methods. Recently, Skeide has given a more direct...

233 Last year saw the posthumous publication of Stephen Jay Gould’s last volume, The Hedgehog, the Fox and the Magister’s Pox (Gould, 2003) with the subtitle ‘Mending and minding the misconceived gap between science and the humanities’. The two protagonists were chosen to represent metaphorically a stereotypical disparity between two different ways of ‘knowing’ or looking at nature. The hedgeho...

We introduce a new way of composing proofs in rule-based proof systems that generalizes tree-like and dag-like proofs. In the new definition, proofs are directed graphs of derived formulas, in which cycles are allowed as long as every formula is derived at least as many times as it is required as a premise. We call such proofs circular. We show that, for all sets of standard inference rules, ci...

Language identification of written text has been studied for several decades. Despite this fact, most of the research is focused on a few most spoken languages, whereas the minor ones are ignored. The identification of a larger number of languages brings new difficulties that do not occur for a few languages. These difficulties are causing decreased accuracy. The objective of this paper is to i...

Changes in laws are reflected – even foreshadowed on occasion – by the field’s scholarship. In the 1980s, there were few who recognized that adults with disabilities were an important resource in the education of students with disabilities or that issues of race and culture had consequence for identifying and delivering services to these children. It is striking that this special issue of the L...

This paper describes features of a language approach for map algebra based on the use of algebraic expressions that satisfy a concise formalism. To be consistent with formal approaches such as geoalgebra and image algebra, the proposed algebraic expressions are suitable not only for the usual modeling of layers but also to describe variable neighborhoods and zones. As a compromise between langu...