Service-oriented modeling for e-business applications components

The emerging trends for e-business engineering revolve around specialisation and cooperation. Successful companies focus on their core competences, and rely on a network of business partners for the support services required to compose a comprehensive offer for their customers. Modulariy is crucial for a flexible e-business infrastructure, but related requirements seldom reflect on the design and operational models of business information systems. Software components are widely used for the implementation of e-business applications, with proved benefits in terms of system development and maintenance. We propose a service-oriented componentisation of ebusiness systems as a way to close the gap with the business models they support. Blurring the distinction between external services and internal capabilities, we propose a homogeneous model for the definition of ebusiness applications components. After a brief discussion on the foundational aspects of the approach, we present the process-based technique we adopted for component modelling. We then present an infrastructure compliant with the model proposed that we built on top of an EJB (Enterprise Java Beans) platform

Thermalisation of inhomogeneous quantum scalar fields in 1+1D

Using an improved version of the Hartree approximation, allowing for ensembles of inhomogeneous configurations, we show in a $\lambda \phi^4$ theory, that initially the system thermalises with a Bose-Einstein distribution. For later times and larger couplings we see deviations.Comment: Presented at CAPP 2000, 4 pages including figures, typo's correcte

Using the event calculus for tracking the normative state of contracts

In this work, we have been principally concerned with the representation of contracts so that their normative state may be tracked in an automated fashion over their deployment lifetime. The normative state of a contract, at a particular time, is the aggregation of instances of normative relations that hold between contract parties at that time, plus the current values of contract variables. The effects of contract events on the normative state of a contract are specified using an XML formalisation of the Event Calculus, called ecXML. We use an example mail service agreement from the domain of web services to ground the discussion of our work. We give a characterisation of the agreement according to the normative concepts of: obligation, power and permission, and show how the ecXML representation may be used to track the state of the agreement, according to a narrative of contract events. We also give a description of a state tracking architecture, and a contract deployment tool, both of which have been implemented in the course of our work.

Damping and the Hartree Ensemble Approximation

We study a Hartree ensemble approximation for real-time dynamics in the toy model of 1+1 dimensional scalar field theory. Damping behavior seen in numerical simulations is compared with analytical predictions based on perturbation theory in the original (non-Hartree-approximated) model