Computing as compression: An overview of the SP theory and system

This article is an overview of a programme of research based on the conjecture thatall kinds of computing and formal reasoning may usefully be understood as information compression by pattern matching, unification and metrics-guided search. The research aims to develop this idea into a theory of computing to integrate and simplify diverse concepts in the field. The research also aims to develop a ‘new generation’ computing system, based on the theory, to integrate and simplify diverse kinds of computing and to achieve more flexibility and ‘intelligence’ than conventional computers. Software simulations of the proposed new system provide a concrete expression of the developing theory and a test-bed for the ideas. The background to the research is briefly reviewed including evidence that information compression is a significant element in biological information processing systems. Concepts ofinformation andredundancy are described as a basis for describing how information compression may be achieved by the comparison ormatching of patterns, the merging orunification of patterns which are the same, together withmetrics-guided search (e.g., ‘hill climbing’, ‘beam search’) to maximise compression for a given computational effort. The main elements of the SP theory and of the proposed SP system are described with a summary of developments to date. Some of the kinds of computing which be interpreted as information compression are briefly reviewed. These include: the ‘low level’ workings of conventional computers; information retrieval, pattern recognition and de-referencing of identifiers; unsupervised inductive learning (grammatical inference, data mining, automatic organisation of software and of knowledge bases); the execution of mathematical or computing functions; deductive and probabilistic inference; parsing and natural language processing; planning and problem solving. Areas of uncertainty where further work is needed are indicated at appropriate points throughout the article.     

Magnetodynamical modes in a ferrite-filled coaxial cavity

The resonance frequencies of a coaxial ferrite-filled cavity and the field distribution in the cavity are calculated. There are three different groups of modes to be distinguished: the limit-TEM mode, the EH and HE modes, and modes independent of the zco-ordinate, which are TM modes. The eigenvalue equation for all modes is derived and discussed.     

Oxygenated fatty acids of oil from sunflower seeds after prolonged storage

Chemical analysis of a number of sunflower (Helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide-reactive material. To characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from Uruguay, Turkey, and Yugoslavia that had been subjected to prolonged storage. Two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combination of column chromatography and countercurrent distribution. The epoxy acids arecis-9,10-epoxystearic acid (0.5%) andcis-9,10-epoxy-cis-12-octadecenoic (coronaric) acid (2.2%). Characterization of the dienols revealed that they are 9-hydroxy-trans-10,cis-12-octadecadienoic acid (1.2%) and 13-hydroxy-cis-9,trans-11-octadecadienoic acid (1.3%). Fresher seed of some of these introductions contained less of the oxygenated components. Oil from recently produced seed of selected high-oil Russian sunflower varieties, including some currently grown in the United States, contained no more than trace amounts of oxygenated acids. Though the relative contributions of genetic and environmental factors toward genesis of oxygenated acids are not established, increase of those acids in some sunflower lines as a result of storage has been demonstrated. Presented at the AOCS-AACC Joint Meeting, Washington, D. C., April 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Overdamped nonlinear systems

Overdamped solutions toddot{z} + KF(z, dot{z}) = 0, z(0) = z_{0}, dot{z}(0) = dot{z}_{0}, are defined to be those that are asymptotically stable to the origin and which are zero at most once for0 < t < x. The main result is a lower bound on the positive constantKto ensure that solutions to the equation are overdamped.