Existing resource brokers for computational Grids only focus on locating a machine (computational resource) within a cluster that has the least load. Such simple brokers are ineffective in commercial and complex environments where negotiation over price, time and service-level agreements are required to establish a contract before users are authorised to use a computational resource. This paper presents a brokering system, utilising the Job Submission Description Language (JSDL) standard and extends the Unicore/GS Resource Broker, that extends brokering with scheduling (resource availability) and simple pricing policy management. The brokering system improves the effectiveness in negotiating contracts for the use of computational resources on the Grid. The architecture and implementation have developed a plug-in for Unicore/GS Resource broker and integrates an externally hosted calendaring service to support the described functionality, and demonstrates the feasibility of building systems by composing autonomous services hosted on the network.

The Web services and service-oriented architectures (SOA) vision by Helland, P. (2005) is about building large-scale distributed applications by composing coarse-grained autonomous services in a flexible architecture that can adapt to changing business requirements. These services interact by exchanging one-way messages through standardized message processing and transport protocols. This vision is being driven by economic imperatives for integration and automation across administrative and organizational boundaries. This paper presents a concise yet expressive model for service contracts to describe messaging behavior. The idea is simple: we use Boolean conditions to specify when a message can be sent and received, where the conditions refer only to other messages in the service contract - that is, conditions only refer to a service's externalized messaging state and not to internal state

This paper specifies an advance reservation and co-allocation protocol for grid computing, and a simple framework for supporting well defined charging models. The protocol supports arbitrary level of nesting, that is a reservation may be to a virtual resource (a set of resources). The work is motivated by the need for advance reservation in the RealityGrid project. However the protocol is a generic protocol that can reserve any type of resource (e.g. clusters, network, and storage) and for any grid project where users need to reserve one or more resources in advance.

One important trend in enterprise-scale IT has been the increasing use of business-business integration (B2Bi) technologies to automate business processes that cross organizational boundaries, such as the interactions between partner companies along a supply chain. It is relatively easy to describe a pattern of interaction, or choreography, in the case where everything proceeds smoothly. However, the abnormal cases, such as where a process fails or a message is lost, are much more complicated, and risk introducing data and process inconsistencies into computer-based systems. Current B2Bi technologies do not supply an infrastructure that can provide reliability without considerable sophistication from the architects and developers. As a first step towards guiding architects to the design of B2Bi systems that maintain consistency despite failures, this paper describes a variety of types of failure that can arise in practice, based on a realistic e-procurement scenario. We describe these failures in terms of the different types of state that naturally occur within the distributed system. Understanding the types of failure that need to be handled, or prevented, is essential to an architect or developer who must design and write handlers for all the exceptions that can occur in their workflows.

An important problem in designing infrastructure to support business-to-business integration (B2Bi) is how to cancel a long-running interaction (either because the user has changed their mind, or in response to an unrecoverable failure). We review the fault-handling and compensation mechanism that is now used in most workflow products and business process modeling standards. We then use an e-procurement case-study to extract a set of requirements for an effective cancellation mechanism, and we show that the standard approach using fault-handling, and compensation transactions is not adequate to meet these requirements.

Spatial information systems are employed to record the schematics of large networks for utilities and telecommunication organisations. Concurrent users access the spatial information systems to insert new designs, update designs and to record the current status of the network. Concurrency must be managed such that the data is not corrupted. This paper introduces a model for long duration transactions based on the use of integrity constraints. The model, called COLT (COnstraint-based Long Transaction), is domain-independent but is especially suitable for spatial information systems and domains where its intent naturally manifests constraints that relate data items. User-defined constraints and database integrity constraints are used both to specify the correctness criteria and to manage long duration ad-hoc transactions. The model is a generalisation of the traditional ACID transaction model. The approach enables the specification of the correctness criteria to be declarative and the user needs no knowledge of the semantics of other concurrently executing transactions. The COLT model is formally specified using the external actions of the I/O automata method and correctness is defined with respect to that method. Correctness is defined independent of implementation.

In this article, we model and verify a data manager whose algorithm is based on ARIES. The work uses the I/O automata method as the formal model and the definition of correctness is defined on the interface between the scheduler and the data manager.