TOSAR – A Topological Method for the Representation of Synthetic and Analytical Relations of Concepts

In mechanized systems used for searching in literature stores there is a steadily growing necessity not only to be able to formulate concepts as a search condition but also the characteristic connections under which these concepts appear in the inquiry. In this way the precision of the mechanized literature search is considerably increased. TOSAR has been developed in order to improve computerized literature searching in this respect.     

Rapprochement of artificial intelligence and dynamics

It is proposed that continuous time is in effect discretized in the brain by dynamic pattern recognition mechanisms in neurons. Time discretization is required to support formal computations in continuous time systems consisting of a large number of components. The ability to perform formal computations is necessary if the system is to execute high level algorithms of the type used in present day artificial intelligence. The weakness of such algorithms is that they work efficiently only when the forms of patterns and objects presented to them are highly constrained. The dynamic mechanisms which discretize the brain's time line also serve to code patterns into constrained forms suitable for high level processing.     

Parallel variable metric algorithms for unconstrained optimization

We classify Straeter's ideas for parallel unconstrained optimization and apply them to Huang's class of updating formulas. Straeter's rank-one updating formula appears to be the only parallel extension within Huang's class with the property of quadratic termination. We also develop a parallel extension of Broyden's (1965) rank-one updating formula and prove quadratic termination. Finally, we present numerical results, obtained by testing the algorithms on several standard example problems.     

Guidance for accredited laboratories on the use of computers

 We review the draft international standard ISO/IEC 17025 and the EA guidelines; and present the existing National Physical Laboratory publication “Software in scientific instruments” and the new Measurement System Validation Best Practice guide. Received: 2 November 1999 / Accepted: 29 January 2000     

Qualification and validation of software and computer systems in laboratories

 Existing software and computer systems in laboratories require retrospective evaluation and validation if their initial validation was not formally documented. The key steps in this process are similar to those for the validation of new software and systems: user requirements and system specification, formal qualification, and procedures to ensure ongoing performance during routine operation. The main difference is that frequently qualification of an existing system is based primarily on reliable operation and proof of performance in the past rather than on qualification during development and installation. Received: 30 April 1998 · Accepted: 2 June 1998     

Qualification and validation of software and computer systems in laboratories

 When software and computer systems are purchased from vendors, the user is still responsible for the overall validation. Because the development validation can only be done by the developers, the user can delegate this part to the vendor. The user's firm should have a vendor qualification program in place to check for this. The type of qualification depends very much on the type and complexity of software and can go from documented evidence of ISO 9001 or equivalent certification for off-the-shelf products to direct audit for software that has been developed on a contract basis. Using a variety of practical examples, the article will help to find the optimal qualification procedure. Received: 8 August 1997 · Accepted: 12 September 1997     

Possibilities and limitations of delegated literature searches by computer

The present-day chemist is constantly on the lookout for information which may be useful to his work. If he is able to define his interests precisely enough then he can avail himself of information scientists and of specialized literature stores. However, retaining access to such information, which only he himself can subjectively judge for relevance to his work, and which most often constitutes a powerful incentive to his creative thinking, will always require his own “browsing” literature studies or personal contacts. These are the limitations of any delegated literature search.     

A Parallel Shallow Water Finite Element Solver for the Venice Lagoon

The aim of this paper is to investigate the concurrent implementation on Multiple Instruction, Multiple Data (MIMD) distributed memory multiprocessors of a shallow water finite element model built to simulate the tidal motion in the Venice lagoon. A recursive technique is used to partition the meshed computational domain into subdomains of (almost) equal number of elements, a requisite for balance the workload on parallel computers.     

Peer interactions in a computer lab: reflections on results of a case study involving web-based dynamic geometry sketches

A case study, originally set up to identify and describe some benefits and limitations of using dynamic web-based geometry sketches, provided an opportunity to examine peer interactions in a lab. Since classes were held in a computer lab, teachers and pairs faced the challenges of working and communicating in a lab environment.Research has shown that particular teacher interventions provide motivation for the consideration of new ideas, and help uncover misunderstandings that may interfere with student progress [Towers, J. (1999). In what ways do teachers interventions interact with and occasion the growth of students’ mathematical understanding. Doctoral Dissertation, University of British Columbia, Unpublished]. Examples of student discourse presented here suggest that certain peer interactions act in similar ways—helping propel students towards new understanding. On the other hand, they also show that some peer interactions, although superficially similar to teacher interventions, may hamper student progress.     

Finite element ground-water models implemented on vector computers

Finite element models, optimized for running on conventional serial computers, are not suitable to make use of the potentional high performance of today's vector or parallel computers. Also, automatic vectorization by the compiler or manual vectorization at the local level do not by far lead to the required and expected computational speed. A global change of the overall program logic or a complete redesign becomes necessary, i.e. a completely new generation of program systems has to be created, considering the new hardware characteristics and abilities. A new computer-independent programming technique for finite element problems to be implemented on vector computers is proposed and the test results of scalar and vectorized program structures on a conventional serial and on a non-conventional pipeline computer are discussed.