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Technique for authentication, access control and resource management in open distributed systems
(1994)
A consistent approach to authentication and access control is proposed. In this new approach, resource management is included. By combining the properties of public key encryption with cascading proxies a single mechanism ...
Optimization and automatic differentiation in Ada : some practical experience
(1994)
This paper describes an investigation into the performance of three Ada packages for automatic differentiation. Two of these implement the forward accumulation approach while the third employs reverse accumulation. Each ...
Reverse accumulation of functions containing gradients
(1993)
We extend the technique of reverse accumulation so as to allow efficient extraction of gradients of scalar valued functions which are themselves constructed by composing operations which include taking derivatives of ...
Positive fixed points of lattices under semigroups of positive linear operators
(University of Hertfordshire, 1993)
Let Z be a Banach lattice endowed with positive cone C and an order-continuous norm [...]. Let G be a semigroup of positive linear endomorphisms of Z. We seek conditions on G sufficient to ensure that the positive fixed ...
Automatic Hessians by reverse accumulation
(1992)
Let n be the number of independent variables of a function f, and let W and S respectively be the time and space bounds for the joint evaluation of {f, f} using automatic differentiation with reverse accumulation. In this ...
Reverse accumulation and accurate rounding error estimates for taylor series coefficient
(1992)
We begin by extending the technique of reverse accumulation so as to obtain gradients of univariate Taylor series coefficients. This is done by re-interpreting the same formulae used to reverse accumulategradients in the ...
Why is software development so difficult to manage?
(University of Hertfordshire, 1992)
Software is extremely complex, invisible and easy to change. Because it's so plastic, it's tempting to make lots of changes. Software is also an amazingly unforgiving medium with which to work. Changes to software frequently ...
Testing should help to insert new bugs or how to modify programs predictably?
(University of Hertfordshire, 1992)
Software maintenance is often regarded as consisting of two different activities, fixing bugs and modifying the code to adapt to changing requirements. We argue that these activities are really two faces of the same coin, ...
Relative width of sublattices
(1991)
Kendall has given a geometrical characterization of vector lattices among the vector spaces with a generating cone. The characterizing property is that the cone should have a linearly compact simplex as a base. Among the ...
Optimizing real-time transport protocols
(University of Hertfordshire, 1990)
A real-time transport protocol must trade delay against loss. Here we consider the problem of minimizing the mean transport delay subject to a given maximum acceptable loss rate. This form of the trade-off is appropriate ...