Stephen Crouch

The Software Sustainability Institute: Changing Research Software Attitudes and Practices

To effect change, the Software Sustainability Institute works with researchers, developers, funders, and infrastructure providers to identify and address key issues with research software.

M-Grid: using ubiquitous web technologies to create a computational grid

There are many potential users and uses for grid computing. However, the concept of sharing computing resources excites security concerns and, whilst being powerful and flexible, at least for novices, existing systems are complex to install and use. Together these represent a significant barrier to potential users who are interested to see what grid computing can do. This paper describes M-grid, a system for building a computational grid which can accept tasks from any user with access to a web browser and distribute them to almost any machine with access to the internet and manages to do this without the installation of additional software or interfering with existing security arrangements.

Implementing hierarchical features in a graphically based formal modelling language

Many developers who could benefit from building and analysing formal models of their systems are deterred from doing so by the process algebra style input languages of formal modelling languages which they find difficult to read and understand. This barrier to the adoption of formal modelling techniques can be significantly reduced if the process algebra is replaced with a graphical notation supported by a model generation tool. However, whilst having a diagrammatic base for the language appeals to the novice modeller, the diagrams can become cluttered for larger models. In this paper we address the issues of how to add hierarchical features to a graphical language without losing the fundamental benefits and appeal of having the graphical interface to the language. We illustrate these ideas using an existing formal modelling language

DataWarp: Building Applications Which Make Progress in an Inconsistent World

The usual approach to dealing with imperfections in data is to attempt to eliminate them. However, the nature of modern systems means this is often futile. This paper describes an approach which permits applications to operate notwithstanding inconsistent data. Instead of attempting to extract a single, correct view of the world from its data, a DataWarp application constructs a collection of interpretations. It adopts one of these and continues work. Since it acts on assumptions, the DataWarp application considers its recent work to be provisional, expecting eventually most of these actions will become definitive. Should the application decide to adopt an alternative data view, it may then need to void provisional actions before resuming work. We describe the DataWarp architecture, discuss its implementation and describe an experiment in which a DataWarp application in an environment containing inconsistent data achieves better results than its conventional counterpart.

RICES: reasoning about information consistency across enterprise solutions

This is a new project presently funded for 4 years by EPSRC. The project is based at the University of Southampton working in collaboration with ICL and DERA. It is concerned with understanding and seeking solutions to the problems that accrue when large systems are integrated. The particular focus of this project is to understand how to manage inconsistent data.

Building Computational Grids Using Ubiquitous Web Technologies

Grid computing is an exciting development which promises to be the enabling technology for many users with periodic requirements for massive computing power. There are a number of Grid computing infrastructures available which are fully featured, powerful, efficient and secure. However, for novice users, these systems are not easy to setup and use which presents a significant barrier to their adoption. M grid offers an alternative approach which permits the creation of a computational grid able to accept tasks from any user with access to the web and distribute them to machines running standard a web browser without any security implications.

Towards a scalable, open-standards service for brokering cross-protocol data transfers across multiple sources and sinks

Data Transfer Service (DTS) is an open-source project that is developing a document-centric message model for describing a bulk data transfer activity, with an accompanying set of loosely coupled and platform-independent components for brokering the transfer of data between a wide range of (potentially incompatible) storage resources as scheduled, fault-tolerant batch jobs. The architecture scales from small embedded deployments on a single computer to large distributed deployments through an expandable ‘worker-node pool’ controlled through message-orientated middleware. Data access and transfer efficiency are maximized through the strategic placement of worker nodes at or between particular data sources/sinks. The design is inherently asynchronous, and, when third-party transfer is not available, it side-steps the bandwidth, concurrency and scalability limitations associated with buffering bytes directly through intermediary client applications. It aims to address geographical–topological deployment concerns by allowing service hosting to be either centralized (as part of a shared service) or confined to a single institution or domain. Established design patterns and open-source components are coupled with a proposal for a document-centric and open-standards-based messaging protocol. As part of the development of the message protocol, a bulk data copy activity document is proposed for the first time.

Utilising Located Functions to Model and Optimise Distributed Computations

With developments in grid computing and Web based data storage the task of orchestrating computations is becoming ever more difficult. Identifying which of the available computation resources and datasets to use is not trivial: it requires reasoning about the problem itself and the cost of moving data to complete the computation efficiently. This paper presents a conceptual notation and performance model that enables e-researchers to reason about their computations and make choices about the best use of resources.

Effects of introducing survival behaviours into automated negotiators specified in an environmental and behavioural framework

With the rise of distributed e-commerce in recent years, demand for automated negotiation has increased. In turn, this has engendered a demand for ever more complex algorithms to conduct these negotiations. As the complexity of these algorithms increases, our ability to reason about and predict their behaviour in an ever larger and more diverse negotiation environment decreases. In addition, with the proliferation of internet-based negotiation, any algorithm also has to contend with potential reliability issues in the underlying message-passing infrastructure. These factors can create problems for building these algorithms, which need to incorporate methods for survival as well as negotiation.This paper proposes a simple yet effective framework for integrating survivability into negotiators, so they are better able to withstand imperfections in their environment. An overview of this framework is given, with two examples of how negotiation behaviour can be specified within this framework. Results of an experiment which is based on these negotiation algorithms are provided. These results show how the stability of a negotiation community is affected by incorporating an example survival behaviour into negotiators operating in an environment developed to support this framework.

Effects of introducing survival behaviours into automated negotiators

With the rise of distributed e-commerce in recent years, demand for automated negotiation has increased. In turn, this has facilitated a demand for ever more complex algorithms to conduct these negotiations. As the complexity of these algorithms increases, our ability to reason about and predict their behaviour in an ever larger and more diverse negotiation environment decreases. In addition, with the proliferation of internet-based negotiation, any algorithm also has to contend with potential reliability issues in the underlying message-passing infrastructure. These factors can create problems for building these algorithms, which need to incorporate methods for survival as well as negotiation. This paper proposes a simple yet effective framework for integrating survivability into negotiators, so they are better able to withstand imperfections in their environment. Results of an experiment are provided which show how the stability of a negotiation community is affected by incorporating an example survival behaviour into negotiators operating in an environment developed to support this framework.