Research Professor Department of Computer Science, University of Sheffield (original appointment 1995). Chaire d’Excellence Agence Nationale de la Recherche Chaire d’Excellence at the Internet Memory Foundation, Paris, (2011-2012). Visiting Professor (2009) Universit´e Joseph Fourier, Grenoble. Visiting Scientist (2005 to 2006) Digital Enterprise Research Institute, National University of Ireland at Galway. Research Associate (1991 to 1995) Centre for Computational Linguistics, University of Manchester Institute of Science and Technology (UMIST). Lecturer (1993-4) in Computing (part-time), University College Salford. Programmer (1988-1990) with S.A.M. Systems Ltd., Manchester. Sound Engineer (1984-1985) with Woodbine Street Recording Studio, Leamington Spa.