School of Computing - Research - Working Papers - 1987

Working Papers for 1987

Current Issues in Introducing and Managing Information Technology: The Chief Executive's Perspective,
John A. Moynihan

This paper describes fifteen chief executives' perceptions of the main issues they are currently experiencing in introducing and managing information technology in their organisations. Although many points and concerns were raised, the great majority of these revolve around five main themes: The level of integration of systems within the organisation; The level of integration of systems across operating subsidiaries; Management involvement and management training in information technology; Information technology, business strategy and the relationship with the customer; Identifying the "pay-off" of the firm's investment in information technology.

A Well-Drawn Graph is Hard to Find,
M. O'hEigeartaigh

A new heuristic for the crossing number problem is developed which calls the linear ordering algorithm as a subroutine. The integer-valued linear ordering problem is shown to be equivalent to the problem of minimising the crossing number of "generalised" bipartite graphs. This leads to the concept of a crossing coefficient which enables us to apply cluster analysis to the solution of linear ordering problems. Applications in channel routing, finding representations of acyclic digraphs and a class of scheduling problems are discussed.

The Simulation of Systems as Times Sequences of Events,
C. McAlister

This paper is an examination of the time dependent behaviour of systems and their simulation as sequences of discrete events. The simulation method is based on a timed Petri net model. A definition language is used to define the model system. A simulator executes the model, provides a display of system events and reports on system performance. Example applications include an alarm system, manufacturing work flow and data communication protocols.

On the Efficient Generation of MultiPrecision Rational Approximations,
M. Scott.

This paper introduces the concepts of a Regular Continued Fraction Generator (RCFG) and a Rational approximation Builder (RAB) and their application to the construction of MultiPrecision Rational Approximations. Three useful types of RCFGs are considered. One interesting application of the method is to efficient high precision O(n2) calculation of certain constants, in particular small square roots and e.

On the Decomposition of Sparse Systems of Linear Equations,
M. O'hEigeartaigh.