Showing papers in "The Computer Journal in 1974"

Numerical Inversion of Laplace Transforms: An Efficient Improvement to Dubner and Abate's Method

Abstract: An accurate method is presented for the numerical inversion of Laplace transform, which is a natural continuation to Dubner and Abate's method. (Dubner and Abate, 1968). The advantages of this modified procedure are twofold: first, the error bound on the inverse f{t) becomes independent of t, instead of being exponential in t; second, and consequently, the trigonometric series obtained for fit) in terms of F(s) is valid on the whole period 2T of the series. As it is proved, this error bound can be set arbitrarily small, and it is always possible to get good results, even in rather difficult cases. Particular implementations and numerical examples are presented.

Drawing Contours from Arbitrary Data Points

Abstract: This paper describes a computer method for drawing, on an incremental plotter, a set of contours when the height is available only for some arbitrary collection of points. The method is based on a distance-weighted, least-squares approximation technique, with the weights varying with the distance of the data points. It is suitable not only for mathematically derived data, but also for data of geographical and other non-mathematical origins, for which numerical approximations are not usually appropriate. The paper includes a comparison with other approximation techniques.

Ordered hash tables

Abstract: : Some variants of the traditional hash method, making use of the numerical or alphabetical order of the keys, lead to faster searching at the expense of a little extra work when items are inserted. The paper presents the new algorithms and analyzes their average running time. (Author)

Source Language Debugging on a Small Computer

Abstract: Conventional dynamic debugging techniques are often restricted to machine level programs, while fully conversational compilers for powerful languages are costly to develop and will not fit into small systems. This paper describes a source-language debugging system for CORAL 66 which allows a user to run his CORAL program under teletype control, and to make changes to the source program. The changes are compiled by the debugging program and immediately incorporated into the object code. This provides a useful facility which can be added to all but the smallest systems.

The Patient Medical Record as a Database

Abstract: Introduction An early real-time filing system for medical records at King's College Hospital soon demonstrated a need for planning patient-based information on a grand scale. The filing system was adequate for the early real-time applications but soon all kinds of patient-based batch systems began to appear, and even real-time applications acquired their own archive files. This fragmentation of related data sets suggests a database solution. Computerised patient records may be a 'natural' for database technology since there is so much replication of data across the information systems in the health care services. The content of a referral letter, say, from General Practitioner to Clinic, or vice versa, should largely be recorded somewhere already. There are numerous examples of this kind both within the units of health care—hospitals, health centres, etc.—and across them.

Allocation of Computer Resources through Flexible Pricing

Abstract: Flexible pricing has been suggested as a means of effectively and efficiently allocating computer resources. The flexible pricing systems that have been implemented, however, tend to arrive at pricing schedules through the intuitive abilities of those individuals responsible for administering the pricing system. This paper will present an analytical technique for determining a pricing schedule and include it within a management control system for the allocation of computer resources. An example of the control system in operation is also provided. (Received November 1973)