Mitsch’s natural partial order on the semigroup of binary relations has a complex relationship with the compatible partial order of inclusion. This relationship is explored by means of a sublattice of the lattice of preorders on the semigroup. The natural partial order is also characterised by equations in the theory of relation algebras. 1. Natural partial orders Having formulated a characteri...

MANET security is becoming a challenge for researchers with the time. The lack of infrastructure gives rise to authentication problems in these networks. Most of the TTP and nonTTP based schemes seem to be impractical for being adopted in MANETs. A hybrid keymanagement scheme addressed these issues effectively by pre-assigned logins on offline basis and issuing certificates on its basis using 4...

MANET security is becoming a challenge for researchers with the time. The lack of infrastructure gives rise to authentication problems in these networks. Most of the TTP and non-TTP based schemes seem to be impractical for being adopted in MANETs. A hybrid key-management scheme addressed these issues effectively by pre-assigned logins on offline basis and issuing certificates on its basis using...

This paper describes the concept of a delegation issuing service (DIS), which is a service that issues X.509 attribute certificates on behalf of an attribute authority (typically a manager). The paper defines the X.509 certificate extensions that are being proposed for the 2005 edition of X.509 in order to implement the DIS concept, as well as the additional steps that a relying party will need...

It should be noted that there are widely varying definitions of the term ̀ agent'. This document will not attempt to provide an authoritative definition, but will mention some qualities shared by most agents and raise some of the inherited problems associated to these concepts. A software agent is a piece of software which acts to accomplish tasks on behalf of its user. Many agents are based on ...

In this paper, which follows closely the talk given at the conference, I will sketch an example of a non-trivial element of K2 of a certain threefold, whose existence is related to the vanishing of an incomplete L-function of a modular form at s = 1. To explain how this fits into a general picture, we begin with a simple account, for the non-specialist, of some of the conjectures (mostly due to...

We propose some new additive Runge–Kutta methods of orders ranging from 2 to 4 that may be used for solving some nonlinear system of ODEs, especially for the temporal discretization of some nonlinear systems of PDEs with constraints. Only linear ODEs or PDEs need to be solved at each time step with these new methods. © 2005 Elsevier B.V. All rights reserved.

Sensornet protocols periodically broadcast beacons for neighborhood information advertisement, but beacon transmissions are costly when power-saving radio duty cycling mechanisms are used. We show that piggybacking multiple beacons in a single transmission significantly reduces transmission costs and argue that this shows the need for a new layer in the sensornet stack—an announcement layer—tha...